xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision 0626367202ced4ab46410c15357eed0ad8be6d5c)
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::NoFree:
643     return bitc::ATTR_KIND_NOFREE;
644   case Attribute::NoImplicitFloat:
645     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
646   case Attribute::NoInline:
647     return bitc::ATTR_KIND_NO_INLINE;
648   case Attribute::NoRecurse:
649     return bitc::ATTR_KIND_NO_RECURSE;
650   case Attribute::NonLazyBind:
651     return bitc::ATTR_KIND_NON_LAZY_BIND;
652   case Attribute::NonNull:
653     return bitc::ATTR_KIND_NON_NULL;
654   case Attribute::Dereferenceable:
655     return bitc::ATTR_KIND_DEREFERENCEABLE;
656   case Attribute::DereferenceableOrNull:
657     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
658   case Attribute::NoRedZone:
659     return bitc::ATTR_KIND_NO_RED_ZONE;
660   case Attribute::NoReturn:
661     return bitc::ATTR_KIND_NO_RETURN;
662   case Attribute::NoSync:
663     return bitc::ATTR_KIND_NOSYNC;
664   case Attribute::NoCfCheck:
665     return bitc::ATTR_KIND_NOCF_CHECK;
666   case Attribute::NoUnwind:
667     return bitc::ATTR_KIND_NO_UNWIND;
668   case Attribute::OptForFuzzing:
669     return bitc::ATTR_KIND_OPT_FOR_FUZZING;
670   case Attribute::OptimizeForSize:
671     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
672   case Attribute::OptimizeNone:
673     return bitc::ATTR_KIND_OPTIMIZE_NONE;
674   case Attribute::ReadNone:
675     return bitc::ATTR_KIND_READ_NONE;
676   case Attribute::ReadOnly:
677     return bitc::ATTR_KIND_READ_ONLY;
678   case Attribute::Returned:
679     return bitc::ATTR_KIND_RETURNED;
680   case Attribute::ReturnsTwice:
681     return bitc::ATTR_KIND_RETURNS_TWICE;
682   case Attribute::SExt:
683     return bitc::ATTR_KIND_S_EXT;
684   case Attribute::Speculatable:
685     return bitc::ATTR_KIND_SPECULATABLE;
686   case Attribute::StackAlignment:
687     return bitc::ATTR_KIND_STACK_ALIGNMENT;
688   case Attribute::StackProtect:
689     return bitc::ATTR_KIND_STACK_PROTECT;
690   case Attribute::StackProtectReq:
691     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
692   case Attribute::StackProtectStrong:
693     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
694   case Attribute::SafeStack:
695     return bitc::ATTR_KIND_SAFESTACK;
696   case Attribute::ShadowCallStack:
697     return bitc::ATTR_KIND_SHADOWCALLSTACK;
698   case Attribute::StrictFP:
699     return bitc::ATTR_KIND_STRICT_FP;
700   case Attribute::StructRet:
701     return bitc::ATTR_KIND_STRUCT_RET;
702   case Attribute::SanitizeAddress:
703     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
704   case Attribute::SanitizeHWAddress:
705     return bitc::ATTR_KIND_SANITIZE_HWADDRESS;
706   case Attribute::SanitizeThread:
707     return bitc::ATTR_KIND_SANITIZE_THREAD;
708   case Attribute::SanitizeMemory:
709     return bitc::ATTR_KIND_SANITIZE_MEMORY;
710   case Attribute::SpeculativeLoadHardening:
711     return bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING;
712   case Attribute::SwiftError:
713     return bitc::ATTR_KIND_SWIFT_ERROR;
714   case Attribute::SwiftSelf:
715     return bitc::ATTR_KIND_SWIFT_SELF;
716   case Attribute::UWTable:
717     return bitc::ATTR_KIND_UW_TABLE;
718   case Attribute::WillReturn:
719     return bitc::ATTR_KIND_WILLRETURN;
720   case Attribute::WriteOnly:
721     return bitc::ATTR_KIND_WRITEONLY;
722   case Attribute::ZExt:
723     return bitc::ATTR_KIND_Z_EXT;
724   case Attribute::ImmArg:
725     return bitc::ATTR_KIND_IMMARG;
726   case Attribute::EndAttrKinds:
727     llvm_unreachable("Can not encode end-attribute kinds marker.");
728   case Attribute::None:
729     llvm_unreachable("Can not encode none-attribute.");
730   }
731 
732   llvm_unreachable("Trying to encode unknown attribute");
733 }
734 
735 void ModuleBitcodeWriter::writeAttributeGroupTable() {
736   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
737       VE.getAttributeGroups();
738   if (AttrGrps.empty()) return;
739 
740   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
741 
742   SmallVector<uint64_t, 64> Record;
743   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
744     unsigned AttrListIndex = Pair.first;
745     AttributeSet AS = Pair.second;
746     Record.push_back(VE.getAttributeGroupID(Pair));
747     Record.push_back(AttrListIndex);
748 
749     for (Attribute Attr : AS) {
750       if (Attr.isEnumAttribute()) {
751         Record.push_back(0);
752         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
753       } else if (Attr.isIntAttribute()) {
754         Record.push_back(1);
755         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
756         Record.push_back(Attr.getValueAsInt());
757       } else if (Attr.isStringAttribute()) {
758         StringRef Kind = Attr.getKindAsString();
759         StringRef Val = Attr.getValueAsString();
760 
761         Record.push_back(Val.empty() ? 3 : 4);
762         Record.append(Kind.begin(), Kind.end());
763         Record.push_back(0);
764         if (!Val.empty()) {
765           Record.append(Val.begin(), Val.end());
766           Record.push_back(0);
767         }
768       } else {
769         assert(Attr.isTypeAttribute());
770         Type *Ty = Attr.getValueAsType();
771         Record.push_back(Ty ? 6 : 5);
772         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
773         if (Ty)
774           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
775       }
776     }
777 
778     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
779     Record.clear();
780   }
781 
782   Stream.ExitBlock();
783 }
784 
785 void ModuleBitcodeWriter::writeAttributeTable() {
786   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
787   if (Attrs.empty()) return;
788 
789   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
790 
791   SmallVector<uint64_t, 64> Record;
792   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
793     AttributeList AL = Attrs[i];
794     for (unsigned i = AL.index_begin(), e = AL.index_end(); i != e; ++i) {
795       AttributeSet AS = AL.getAttributes(i);
796       if (AS.hasAttributes())
797         Record.push_back(VE.getAttributeGroupID({i, AS}));
798     }
799 
800     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
801     Record.clear();
802   }
803 
804   Stream.ExitBlock();
805 }
806 
807 /// WriteTypeTable - Write out the type table for a module.
808 void ModuleBitcodeWriter::writeTypeTable() {
809   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
810 
811   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
812   SmallVector<uint64_t, 64> TypeVals;
813 
814   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
815 
816   // Abbrev for TYPE_CODE_POINTER.
817   auto Abbv = std::make_shared<BitCodeAbbrev>();
818   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
819   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
820   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
821   unsigned PtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
822 
823   // Abbrev for TYPE_CODE_FUNCTION.
824   Abbv = std::make_shared<BitCodeAbbrev>();
825   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
826   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
827   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
828   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
829   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
830 
831   // Abbrev for TYPE_CODE_STRUCT_ANON.
832   Abbv = std::make_shared<BitCodeAbbrev>();
833   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
834   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
835   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
836   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
837   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
838 
839   // Abbrev for TYPE_CODE_STRUCT_NAME.
840   Abbv = std::make_shared<BitCodeAbbrev>();
841   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
842   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
843   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
844   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
845 
846   // Abbrev for TYPE_CODE_STRUCT_NAMED.
847   Abbv = std::make_shared<BitCodeAbbrev>();
848   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
849   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
850   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
851   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
852   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
853 
854   // Abbrev for TYPE_CODE_ARRAY.
855   Abbv = std::make_shared<BitCodeAbbrev>();
856   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
857   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
858   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
859   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
860 
861   // Emit an entry count so the reader can reserve space.
862   TypeVals.push_back(TypeList.size());
863   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
864   TypeVals.clear();
865 
866   // Loop over all of the types, emitting each in turn.
867   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
868     Type *T = TypeList[i];
869     int AbbrevToUse = 0;
870     unsigned Code = 0;
871 
872     switch (T->getTypeID()) {
873     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
874     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
875     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
876     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
877     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
878     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
879     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
880     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
881     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
882     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
883     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
884     case Type::IntegerTyID:
885       // INTEGER: [width]
886       Code = bitc::TYPE_CODE_INTEGER;
887       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
888       break;
889     case Type::PointerTyID: {
890       PointerType *PTy = cast<PointerType>(T);
891       // POINTER: [pointee type, address space]
892       Code = bitc::TYPE_CODE_POINTER;
893       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
894       unsigned AddressSpace = PTy->getAddressSpace();
895       TypeVals.push_back(AddressSpace);
896       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
897       break;
898     }
899     case Type::FunctionTyID: {
900       FunctionType *FT = cast<FunctionType>(T);
901       // FUNCTION: [isvararg, retty, paramty x N]
902       Code = bitc::TYPE_CODE_FUNCTION;
903       TypeVals.push_back(FT->isVarArg());
904       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
905       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
906         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
907       AbbrevToUse = FunctionAbbrev;
908       break;
909     }
910     case Type::StructTyID: {
911       StructType *ST = cast<StructType>(T);
912       // STRUCT: [ispacked, eltty x N]
913       TypeVals.push_back(ST->isPacked());
914       // Output all of the element types.
915       for (StructType::element_iterator I = ST->element_begin(),
916            E = ST->element_end(); I != E; ++I)
917         TypeVals.push_back(VE.getTypeID(*I));
918 
919       if (ST->isLiteral()) {
920         Code = bitc::TYPE_CODE_STRUCT_ANON;
921         AbbrevToUse = StructAnonAbbrev;
922       } else {
923         if (ST->isOpaque()) {
924           Code = bitc::TYPE_CODE_OPAQUE;
925         } else {
926           Code = bitc::TYPE_CODE_STRUCT_NAMED;
927           AbbrevToUse = StructNamedAbbrev;
928         }
929 
930         // Emit the name if it is present.
931         if (!ST->getName().empty())
932           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
933                             StructNameAbbrev);
934       }
935       break;
936     }
937     case Type::ArrayTyID: {
938       ArrayType *AT = cast<ArrayType>(T);
939       // ARRAY: [numelts, eltty]
940       Code = bitc::TYPE_CODE_ARRAY;
941       TypeVals.push_back(AT->getNumElements());
942       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
943       AbbrevToUse = ArrayAbbrev;
944       break;
945     }
946     case Type::VectorTyID: {
947       VectorType *VT = cast<VectorType>(T);
948       // VECTOR [numelts, eltty] or
949       //        [numelts, eltty, scalable]
950       Code = bitc::TYPE_CODE_VECTOR;
951       TypeVals.push_back(VT->getNumElements());
952       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
953       if (VT->isScalable())
954         TypeVals.push_back(VT->isScalable());
955       break;
956     }
957     }
958 
959     // Emit the finished record.
960     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
961     TypeVals.clear();
962   }
963 
964   Stream.ExitBlock();
965 }
966 
967 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
968   switch (Linkage) {
969   case GlobalValue::ExternalLinkage:
970     return 0;
971   case GlobalValue::WeakAnyLinkage:
972     return 16;
973   case GlobalValue::AppendingLinkage:
974     return 2;
975   case GlobalValue::InternalLinkage:
976     return 3;
977   case GlobalValue::LinkOnceAnyLinkage:
978     return 18;
979   case GlobalValue::ExternalWeakLinkage:
980     return 7;
981   case GlobalValue::CommonLinkage:
982     return 8;
983   case GlobalValue::PrivateLinkage:
984     return 9;
985   case GlobalValue::WeakODRLinkage:
986     return 17;
987   case GlobalValue::LinkOnceODRLinkage:
988     return 19;
989   case GlobalValue::AvailableExternallyLinkage:
990     return 12;
991   }
992   llvm_unreachable("Invalid linkage");
993 }
994 
995 static unsigned getEncodedLinkage(const GlobalValue &GV) {
996   return getEncodedLinkage(GV.getLinkage());
997 }
998 
999 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
1000   uint64_t RawFlags = 0;
1001   RawFlags |= Flags.ReadNone;
1002   RawFlags |= (Flags.ReadOnly << 1);
1003   RawFlags |= (Flags.NoRecurse << 2);
1004   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1005   RawFlags |= (Flags.NoInline << 4);
1006   return RawFlags;
1007 }
1008 
1009 // Decode the flags for GlobalValue in the summary
1010 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
1011   uint64_t RawFlags = 0;
1012 
1013   RawFlags |= Flags.NotEligibleToImport; // bool
1014   RawFlags |= (Flags.Live << 1);
1015   RawFlags |= (Flags.DSOLocal << 2);
1016   RawFlags |= (Flags.CanAutoHide << 3);
1017 
1018   // Linkage don't need to be remapped at that time for the summary. Any future
1019   // change to the getEncodedLinkage() function will need to be taken into
1020   // account here as well.
1021   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1022 
1023   return RawFlags;
1024 }
1025 
1026 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1027   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1);
1028   return RawFlags;
1029 }
1030 
1031 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1032   switch (GV.getVisibility()) {
1033   case GlobalValue::DefaultVisibility:   return 0;
1034   case GlobalValue::HiddenVisibility:    return 1;
1035   case GlobalValue::ProtectedVisibility: return 2;
1036   }
1037   llvm_unreachable("Invalid visibility");
1038 }
1039 
1040 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1041   switch (GV.getDLLStorageClass()) {
1042   case GlobalValue::DefaultStorageClass:   return 0;
1043   case GlobalValue::DLLImportStorageClass: return 1;
1044   case GlobalValue::DLLExportStorageClass: return 2;
1045   }
1046   llvm_unreachable("Invalid DLL storage class");
1047 }
1048 
1049 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1050   switch (GV.getThreadLocalMode()) {
1051     case GlobalVariable::NotThreadLocal:         return 0;
1052     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1053     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1054     case GlobalVariable::InitialExecTLSModel:    return 3;
1055     case GlobalVariable::LocalExecTLSModel:      return 4;
1056   }
1057   llvm_unreachable("Invalid TLS model");
1058 }
1059 
1060 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1061   switch (C.getSelectionKind()) {
1062   case Comdat::Any:
1063     return bitc::COMDAT_SELECTION_KIND_ANY;
1064   case Comdat::ExactMatch:
1065     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1066   case Comdat::Largest:
1067     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1068   case Comdat::NoDuplicates:
1069     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1070   case Comdat::SameSize:
1071     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1072   }
1073   llvm_unreachable("Invalid selection kind");
1074 }
1075 
1076 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1077   switch (GV.getUnnamedAddr()) {
1078   case GlobalValue::UnnamedAddr::None:   return 0;
1079   case GlobalValue::UnnamedAddr::Local:  return 2;
1080   case GlobalValue::UnnamedAddr::Global: return 1;
1081   }
1082   llvm_unreachable("Invalid unnamed_addr");
1083 }
1084 
1085 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1086   if (GenerateHash)
1087     Hasher.update(Str);
1088   return StrtabBuilder.add(Str);
1089 }
1090 
1091 void ModuleBitcodeWriter::writeComdats() {
1092   SmallVector<unsigned, 64> Vals;
1093   for (const Comdat *C : VE.getComdats()) {
1094     // COMDAT: [strtab offset, strtab size, selection_kind]
1095     Vals.push_back(addToStrtab(C->getName()));
1096     Vals.push_back(C->getName().size());
1097     Vals.push_back(getEncodedComdatSelectionKind(*C));
1098     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1099     Vals.clear();
1100   }
1101 }
1102 
1103 /// Write a record that will eventually hold the word offset of the
1104 /// module-level VST. For now the offset is 0, which will be backpatched
1105 /// after the real VST is written. Saves the bit offset to backpatch.
1106 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1107   // Write a placeholder value in for the offset of the real VST,
1108   // which is written after the function blocks so that it can include
1109   // the offset of each function. The placeholder offset will be
1110   // updated when the real VST is written.
1111   auto Abbv = std::make_shared<BitCodeAbbrev>();
1112   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1113   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1114   // hold the real VST offset. Must use fixed instead of VBR as we don't
1115   // know how many VBR chunks to reserve ahead of time.
1116   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1117   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1118 
1119   // Emit the placeholder
1120   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1121   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1122 
1123   // Compute and save the bit offset to the placeholder, which will be
1124   // patched when the real VST is written. We can simply subtract the 32-bit
1125   // fixed size from the current bit number to get the location to backpatch.
1126   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1127 }
1128 
1129 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1130 
1131 /// Determine the encoding to use for the given string name and length.
1132 static StringEncoding getStringEncoding(StringRef Str) {
1133   bool isChar6 = true;
1134   for (char C : Str) {
1135     if (isChar6)
1136       isChar6 = BitCodeAbbrevOp::isChar6(C);
1137     if ((unsigned char)C & 128)
1138       // don't bother scanning the rest.
1139       return SE_Fixed8;
1140   }
1141   if (isChar6)
1142     return SE_Char6;
1143   return SE_Fixed7;
1144 }
1145 
1146 /// Emit top-level description of module, including target triple, inline asm,
1147 /// descriptors for global variables, and function prototype info.
1148 /// Returns the bit offset to backpatch with the location of the real VST.
1149 void ModuleBitcodeWriter::writeModuleInfo() {
1150   // Emit various pieces of data attached to a module.
1151   if (!M.getTargetTriple().empty())
1152     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1153                       0 /*TODO*/);
1154   const std::string &DL = M.getDataLayoutStr();
1155   if (!DL.empty())
1156     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1157   if (!M.getModuleInlineAsm().empty())
1158     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1159                       0 /*TODO*/);
1160 
1161   // Emit information about sections and GC, computing how many there are. Also
1162   // compute the maximum alignment value.
1163   std::map<std::string, unsigned> SectionMap;
1164   std::map<std::string, unsigned> GCMap;
1165   unsigned MaxAlignment = 0;
1166   unsigned MaxGlobalType = 0;
1167   for (const GlobalValue &GV : M.globals()) {
1168     MaxAlignment = std::max(MaxAlignment, GV.getAlignment());
1169     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1170     if (GV.hasSection()) {
1171       // Give section names unique ID's.
1172       unsigned &Entry = SectionMap[GV.getSection()];
1173       if (!Entry) {
1174         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1175                           0 /*TODO*/);
1176         Entry = SectionMap.size();
1177       }
1178     }
1179   }
1180   for (const Function &F : M) {
1181     MaxAlignment = std::max(MaxAlignment, F.getAlignment());
1182     if (F.hasSection()) {
1183       // Give section names unique ID's.
1184       unsigned &Entry = SectionMap[F.getSection()];
1185       if (!Entry) {
1186         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1187                           0 /*TODO*/);
1188         Entry = SectionMap.size();
1189       }
1190     }
1191     if (F.hasGC()) {
1192       // Same for GC names.
1193       unsigned &Entry = GCMap[F.getGC()];
1194       if (!Entry) {
1195         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1196                           0 /*TODO*/);
1197         Entry = GCMap.size();
1198       }
1199     }
1200   }
1201 
1202   // Emit abbrev for globals, now that we know # sections and max alignment.
1203   unsigned SimpleGVarAbbrev = 0;
1204   if (!M.global_empty()) {
1205     // Add an abbrev for common globals with no visibility or thread localness.
1206     auto Abbv = std::make_shared<BitCodeAbbrev>();
1207     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1208     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1209     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1210     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1211                               Log2_32_Ceil(MaxGlobalType+1)));
1212     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1213                                                            //| explicitType << 1
1214                                                            //| constant
1215     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1216     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1217     if (MaxAlignment == 0)                                 // Alignment.
1218       Abbv->Add(BitCodeAbbrevOp(0));
1219     else {
1220       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
1221       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1222                                Log2_32_Ceil(MaxEncAlignment+1)));
1223     }
1224     if (SectionMap.empty())                                    // Section.
1225       Abbv->Add(BitCodeAbbrevOp(0));
1226     else
1227       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1228                                Log2_32_Ceil(SectionMap.size()+1)));
1229     // Don't bother emitting vis + thread local.
1230     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1231   }
1232 
1233   SmallVector<unsigned, 64> Vals;
1234   // Emit the module's source file name.
1235   {
1236     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1237     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1238     if (Bits == SE_Char6)
1239       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1240     else if (Bits == SE_Fixed7)
1241       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1242 
1243     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1244     auto Abbv = std::make_shared<BitCodeAbbrev>();
1245     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1246     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1247     Abbv->Add(AbbrevOpToUse);
1248     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1249 
1250     for (const auto P : M.getSourceFileName())
1251       Vals.push_back((unsigned char)P);
1252 
1253     // Emit the finished record.
1254     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1255     Vals.clear();
1256   }
1257 
1258   // Emit the global variable information.
1259   for (const GlobalVariable &GV : M.globals()) {
1260     unsigned AbbrevToUse = 0;
1261 
1262     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1263     //             linkage, alignment, section, visibility, threadlocal,
1264     //             unnamed_addr, externally_initialized, dllstorageclass,
1265     //             comdat, attributes, DSO_Local]
1266     Vals.push_back(addToStrtab(GV.getName()));
1267     Vals.push_back(GV.getName().size());
1268     Vals.push_back(VE.getTypeID(GV.getValueType()));
1269     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1270     Vals.push_back(GV.isDeclaration() ? 0 :
1271                    (VE.getValueID(GV.getInitializer()) + 1));
1272     Vals.push_back(getEncodedLinkage(GV));
1273     Vals.push_back(Log2_32(GV.getAlignment())+1);
1274     Vals.push_back(GV.hasSection() ? SectionMap[GV.getSection()] : 0);
1275     if (GV.isThreadLocal() ||
1276         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1277         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1278         GV.isExternallyInitialized() ||
1279         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1280         GV.hasComdat() ||
1281         GV.hasAttributes() ||
1282         GV.isDSOLocal() ||
1283         GV.hasPartition()) {
1284       Vals.push_back(getEncodedVisibility(GV));
1285       Vals.push_back(getEncodedThreadLocalMode(GV));
1286       Vals.push_back(getEncodedUnnamedAddr(GV));
1287       Vals.push_back(GV.isExternallyInitialized());
1288       Vals.push_back(getEncodedDLLStorageClass(GV));
1289       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1290 
1291       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1292       Vals.push_back(VE.getAttributeListID(AL));
1293 
1294       Vals.push_back(GV.isDSOLocal());
1295       Vals.push_back(addToStrtab(GV.getPartition()));
1296       Vals.push_back(GV.getPartition().size());
1297     } else {
1298       AbbrevToUse = SimpleGVarAbbrev;
1299     }
1300 
1301     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1302     Vals.clear();
1303   }
1304 
1305   // Emit the function proto information.
1306   for (const Function &F : M) {
1307     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1308     //             linkage, paramattrs, alignment, section, visibility, gc,
1309     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1310     //             prefixdata, personalityfn, DSO_Local, addrspace]
1311     Vals.push_back(addToStrtab(F.getName()));
1312     Vals.push_back(F.getName().size());
1313     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1314     Vals.push_back(F.getCallingConv());
1315     Vals.push_back(F.isDeclaration());
1316     Vals.push_back(getEncodedLinkage(F));
1317     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1318     Vals.push_back(Log2_32(F.getAlignment())+1);
1319     Vals.push_back(F.hasSection() ? SectionMap[F.getSection()] : 0);
1320     Vals.push_back(getEncodedVisibility(F));
1321     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1322     Vals.push_back(getEncodedUnnamedAddr(F));
1323     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1324                                        : 0);
1325     Vals.push_back(getEncodedDLLStorageClass(F));
1326     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1327     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1328                                      : 0);
1329     Vals.push_back(
1330         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1331 
1332     Vals.push_back(F.isDSOLocal());
1333     Vals.push_back(F.getAddressSpace());
1334     Vals.push_back(addToStrtab(F.getPartition()));
1335     Vals.push_back(F.getPartition().size());
1336 
1337     unsigned AbbrevToUse = 0;
1338     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1339     Vals.clear();
1340   }
1341 
1342   // Emit the alias information.
1343   for (const GlobalAlias &A : M.aliases()) {
1344     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1345     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1346     //         DSO_Local]
1347     Vals.push_back(addToStrtab(A.getName()));
1348     Vals.push_back(A.getName().size());
1349     Vals.push_back(VE.getTypeID(A.getValueType()));
1350     Vals.push_back(A.getType()->getAddressSpace());
1351     Vals.push_back(VE.getValueID(A.getAliasee()));
1352     Vals.push_back(getEncodedLinkage(A));
1353     Vals.push_back(getEncodedVisibility(A));
1354     Vals.push_back(getEncodedDLLStorageClass(A));
1355     Vals.push_back(getEncodedThreadLocalMode(A));
1356     Vals.push_back(getEncodedUnnamedAddr(A));
1357     Vals.push_back(A.isDSOLocal());
1358     Vals.push_back(addToStrtab(A.getPartition()));
1359     Vals.push_back(A.getPartition().size());
1360 
1361     unsigned AbbrevToUse = 0;
1362     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1363     Vals.clear();
1364   }
1365 
1366   // Emit the ifunc information.
1367   for (const GlobalIFunc &I : M.ifuncs()) {
1368     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1369     //         val#, linkage, visibility, DSO_Local]
1370     Vals.push_back(addToStrtab(I.getName()));
1371     Vals.push_back(I.getName().size());
1372     Vals.push_back(VE.getTypeID(I.getValueType()));
1373     Vals.push_back(I.getType()->getAddressSpace());
1374     Vals.push_back(VE.getValueID(I.getResolver()));
1375     Vals.push_back(getEncodedLinkage(I));
1376     Vals.push_back(getEncodedVisibility(I));
1377     Vals.push_back(I.isDSOLocal());
1378     Vals.push_back(addToStrtab(I.getPartition()));
1379     Vals.push_back(I.getPartition().size());
1380     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1381     Vals.clear();
1382   }
1383 
1384   writeValueSymbolTableForwardDecl();
1385 }
1386 
1387 static uint64_t getOptimizationFlags(const Value *V) {
1388   uint64_t Flags = 0;
1389 
1390   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1391     if (OBO->hasNoSignedWrap())
1392       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1393     if (OBO->hasNoUnsignedWrap())
1394       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1395   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1396     if (PEO->isExact())
1397       Flags |= 1 << bitc::PEO_EXACT;
1398   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1399     if (FPMO->hasAllowReassoc())
1400       Flags |= bitc::AllowReassoc;
1401     if (FPMO->hasNoNaNs())
1402       Flags |= bitc::NoNaNs;
1403     if (FPMO->hasNoInfs())
1404       Flags |= bitc::NoInfs;
1405     if (FPMO->hasNoSignedZeros())
1406       Flags |= bitc::NoSignedZeros;
1407     if (FPMO->hasAllowReciprocal())
1408       Flags |= bitc::AllowReciprocal;
1409     if (FPMO->hasAllowContract())
1410       Flags |= bitc::AllowContract;
1411     if (FPMO->hasApproxFunc())
1412       Flags |= bitc::ApproxFunc;
1413   }
1414 
1415   return Flags;
1416 }
1417 
1418 void ModuleBitcodeWriter::writeValueAsMetadata(
1419     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1420   // Mimic an MDNode with a value as one operand.
1421   Value *V = MD->getValue();
1422   Record.push_back(VE.getTypeID(V->getType()));
1423   Record.push_back(VE.getValueID(V));
1424   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1425   Record.clear();
1426 }
1427 
1428 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1429                                        SmallVectorImpl<uint64_t> &Record,
1430                                        unsigned Abbrev) {
1431   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1432     Metadata *MD = N->getOperand(i);
1433     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1434            "Unexpected function-local metadata");
1435     Record.push_back(VE.getMetadataOrNullID(MD));
1436   }
1437   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1438                                     : bitc::METADATA_NODE,
1439                     Record, Abbrev);
1440   Record.clear();
1441 }
1442 
1443 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1444   // Assume the column is usually under 128, and always output the inlined-at
1445   // location (it's never more expensive than building an array size 1).
1446   auto Abbv = std::make_shared<BitCodeAbbrev>();
1447   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1448   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1449   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1450   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1451   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1452   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1453   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1454   return Stream.EmitAbbrev(std::move(Abbv));
1455 }
1456 
1457 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1458                                           SmallVectorImpl<uint64_t> &Record,
1459                                           unsigned &Abbrev) {
1460   if (!Abbrev)
1461     Abbrev = createDILocationAbbrev();
1462 
1463   Record.push_back(N->isDistinct());
1464   Record.push_back(N->getLine());
1465   Record.push_back(N->getColumn());
1466   Record.push_back(VE.getMetadataID(N->getScope()));
1467   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1468   Record.push_back(N->isImplicitCode());
1469 
1470   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1471   Record.clear();
1472 }
1473 
1474 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1475   // Assume the column is usually under 128, and always output the inlined-at
1476   // location (it's never more expensive than building an array size 1).
1477   auto Abbv = std::make_shared<BitCodeAbbrev>();
1478   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1479   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1480   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1481   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1482   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1483   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1484   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1485   return Stream.EmitAbbrev(std::move(Abbv));
1486 }
1487 
1488 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1489                                              SmallVectorImpl<uint64_t> &Record,
1490                                              unsigned &Abbrev) {
1491   if (!Abbrev)
1492     Abbrev = createGenericDINodeAbbrev();
1493 
1494   Record.push_back(N->isDistinct());
1495   Record.push_back(N->getTag());
1496   Record.push_back(0); // Per-tag version field; unused for now.
1497 
1498   for (auto &I : N->operands())
1499     Record.push_back(VE.getMetadataOrNullID(I));
1500 
1501   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1502   Record.clear();
1503 }
1504 
1505 static uint64_t rotateSign(int64_t I) {
1506   uint64_t U = I;
1507   return I < 0 ? ~(U << 1) : U << 1;
1508 }
1509 
1510 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1511                                           SmallVectorImpl<uint64_t> &Record,
1512                                           unsigned Abbrev) {
1513   const uint64_t Version = 1 << 1;
1514   Record.push_back((uint64_t)N->isDistinct() | Version);
1515   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1516   Record.push_back(rotateSign(N->getLowerBound()));
1517 
1518   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1519   Record.clear();
1520 }
1521 
1522 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1523                                             SmallVectorImpl<uint64_t> &Record,
1524                                             unsigned Abbrev) {
1525   Record.push_back((N->isUnsigned() << 1) | N->isDistinct());
1526   Record.push_back(rotateSign(N->getValue()));
1527   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1528 
1529   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1530   Record.clear();
1531 }
1532 
1533 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1534                                            SmallVectorImpl<uint64_t> &Record,
1535                                            unsigned Abbrev) {
1536   Record.push_back(N->isDistinct());
1537   Record.push_back(N->getTag());
1538   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1539   Record.push_back(N->getSizeInBits());
1540   Record.push_back(N->getAlignInBits());
1541   Record.push_back(N->getEncoding());
1542   Record.push_back(N->getFlags());
1543 
1544   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1545   Record.clear();
1546 }
1547 
1548 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1549                                              SmallVectorImpl<uint64_t> &Record,
1550                                              unsigned Abbrev) {
1551   Record.push_back(N->isDistinct());
1552   Record.push_back(N->getTag());
1553   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1554   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1555   Record.push_back(N->getLine());
1556   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1557   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1558   Record.push_back(N->getSizeInBits());
1559   Record.push_back(N->getAlignInBits());
1560   Record.push_back(N->getOffsetInBits());
1561   Record.push_back(N->getFlags());
1562   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1563 
1564   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1565   // that there is no DWARF address space associated with DIDerivedType.
1566   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1567     Record.push_back(*DWARFAddressSpace + 1);
1568   else
1569     Record.push_back(0);
1570 
1571   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1572   Record.clear();
1573 }
1574 
1575 void ModuleBitcodeWriter::writeDICompositeType(
1576     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1577     unsigned Abbrev) {
1578   const unsigned IsNotUsedInOldTypeRef = 0x2;
1579   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1580   Record.push_back(N->getTag());
1581   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1582   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1583   Record.push_back(N->getLine());
1584   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1585   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1586   Record.push_back(N->getSizeInBits());
1587   Record.push_back(N->getAlignInBits());
1588   Record.push_back(N->getOffsetInBits());
1589   Record.push_back(N->getFlags());
1590   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1591   Record.push_back(N->getRuntimeLang());
1592   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1593   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1594   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1595   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1596 
1597   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1598   Record.clear();
1599 }
1600 
1601 void ModuleBitcodeWriter::writeDISubroutineType(
1602     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1603     unsigned Abbrev) {
1604   const unsigned HasNoOldTypeRefs = 0x2;
1605   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1606   Record.push_back(N->getFlags());
1607   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1608   Record.push_back(N->getCC());
1609 
1610   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1611   Record.clear();
1612 }
1613 
1614 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1615                                       SmallVectorImpl<uint64_t> &Record,
1616                                       unsigned Abbrev) {
1617   Record.push_back(N->isDistinct());
1618   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1619   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1620   if (N->getRawChecksum()) {
1621     Record.push_back(N->getRawChecksum()->Kind);
1622     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1623   } else {
1624     // Maintain backwards compatibility with the old internal representation of
1625     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1626     Record.push_back(0);
1627     Record.push_back(VE.getMetadataOrNullID(nullptr));
1628   }
1629   auto Source = N->getRawSource();
1630   if (Source)
1631     Record.push_back(VE.getMetadataOrNullID(*Source));
1632 
1633   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1634   Record.clear();
1635 }
1636 
1637 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1638                                              SmallVectorImpl<uint64_t> &Record,
1639                                              unsigned Abbrev) {
1640   assert(N->isDistinct() && "Expected distinct compile units");
1641   Record.push_back(/* IsDistinct */ true);
1642   Record.push_back(N->getSourceLanguage());
1643   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1644   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1645   Record.push_back(N->isOptimized());
1646   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1647   Record.push_back(N->getRuntimeVersion());
1648   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1649   Record.push_back(N->getEmissionKind());
1650   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1651   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1652   Record.push_back(/* subprograms */ 0);
1653   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1654   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1655   Record.push_back(N->getDWOId());
1656   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1657   Record.push_back(N->getSplitDebugInlining());
1658   Record.push_back(N->getDebugInfoForProfiling());
1659   Record.push_back((unsigned)N->getNameTableKind());
1660 
1661   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1662   Record.clear();
1663 }
1664 
1665 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1666                                             SmallVectorImpl<uint64_t> &Record,
1667                                             unsigned Abbrev) {
1668   const uint64_t HasUnitFlag = 1 << 1;
1669   const uint64_t HasSPFlagsFlag = 1 << 2;
1670   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
1671   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1672   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1673   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1674   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1675   Record.push_back(N->getLine());
1676   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1677   Record.push_back(N->getScopeLine());
1678   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1679   Record.push_back(N->getSPFlags());
1680   Record.push_back(N->getVirtualIndex());
1681   Record.push_back(N->getFlags());
1682   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1683   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1684   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1685   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
1686   Record.push_back(N->getThisAdjustment());
1687   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
1688 
1689   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1690   Record.clear();
1691 }
1692 
1693 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1694                                               SmallVectorImpl<uint64_t> &Record,
1695                                               unsigned Abbrev) {
1696   Record.push_back(N->isDistinct());
1697   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1698   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1699   Record.push_back(N->getLine());
1700   Record.push_back(N->getColumn());
1701 
1702   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1703   Record.clear();
1704 }
1705 
1706 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1707     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1708     unsigned Abbrev) {
1709   Record.push_back(N->isDistinct());
1710   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1711   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1712   Record.push_back(N->getDiscriminator());
1713 
1714   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1715   Record.clear();
1716 }
1717 
1718 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
1719                                              SmallVectorImpl<uint64_t> &Record,
1720                                              unsigned Abbrev) {
1721   Record.push_back(N->isDistinct());
1722   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1723   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
1724   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1725   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1726   Record.push_back(N->getLineNo());
1727 
1728   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
1729   Record.clear();
1730 }
1731 
1732 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1733                                            SmallVectorImpl<uint64_t> &Record,
1734                                            unsigned Abbrev) {
1735   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1736   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1737   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1738 
1739   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1740   Record.clear();
1741 }
1742 
1743 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1744                                        SmallVectorImpl<uint64_t> &Record,
1745                                        unsigned Abbrev) {
1746   Record.push_back(N->isDistinct());
1747   Record.push_back(N->getMacinfoType());
1748   Record.push_back(N->getLine());
1749   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1750   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1751 
1752   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1753   Record.clear();
1754 }
1755 
1756 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1757                                            SmallVectorImpl<uint64_t> &Record,
1758                                            unsigned Abbrev) {
1759   Record.push_back(N->isDistinct());
1760   Record.push_back(N->getMacinfoType());
1761   Record.push_back(N->getLine());
1762   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1763   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1764 
1765   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1766   Record.clear();
1767 }
1768 
1769 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1770                                         SmallVectorImpl<uint64_t> &Record,
1771                                         unsigned Abbrev) {
1772   Record.push_back(N->isDistinct());
1773   for (auto &I : N->operands())
1774     Record.push_back(VE.getMetadataOrNullID(I));
1775 
1776   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1777   Record.clear();
1778 }
1779 
1780 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1781     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1782     unsigned Abbrev) {
1783   Record.push_back(N->isDistinct());
1784   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1785   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1786 
1787   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1788   Record.clear();
1789 }
1790 
1791 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1792     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1793     unsigned Abbrev) {
1794   Record.push_back(N->isDistinct());
1795   Record.push_back(N->getTag());
1796   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1797   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1798   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1799 
1800   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1801   Record.clear();
1802 }
1803 
1804 void ModuleBitcodeWriter::writeDIGlobalVariable(
1805     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1806     unsigned Abbrev) {
1807   const uint64_t Version = 2 << 1;
1808   Record.push_back((uint64_t)N->isDistinct() | Version);
1809   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1810   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1811   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1812   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1813   Record.push_back(N->getLine());
1814   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1815   Record.push_back(N->isLocalToUnit());
1816   Record.push_back(N->isDefinition());
1817   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1818   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
1819   Record.push_back(N->getAlignInBits());
1820 
1821   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1822   Record.clear();
1823 }
1824 
1825 void ModuleBitcodeWriter::writeDILocalVariable(
1826     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
1827     unsigned Abbrev) {
1828   // In order to support all possible bitcode formats in BitcodeReader we need
1829   // to distinguish the following cases:
1830   // 1) Record has no artificial tag (Record[1]),
1831   //   has no obsolete inlinedAt field (Record[9]).
1832   //   In this case Record size will be 8, HasAlignment flag is false.
1833   // 2) Record has artificial tag (Record[1]),
1834   //   has no obsolete inlignedAt field (Record[9]).
1835   //   In this case Record size will be 9, HasAlignment flag is false.
1836   // 3) Record has both artificial tag (Record[1]) and
1837   //   obsolete inlignedAt field (Record[9]).
1838   //   In this case Record size will be 10, HasAlignment flag is false.
1839   // 4) Record has neither artificial tag, nor inlignedAt field, but
1840   //   HasAlignment flag is true and Record[8] contains alignment value.
1841   const uint64_t HasAlignmentFlag = 1 << 1;
1842   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
1843   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1844   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1845   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1846   Record.push_back(N->getLine());
1847   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1848   Record.push_back(N->getArg());
1849   Record.push_back(N->getFlags());
1850   Record.push_back(N->getAlignInBits());
1851 
1852   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1853   Record.clear();
1854 }
1855 
1856 void ModuleBitcodeWriter::writeDILabel(
1857     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
1858     unsigned Abbrev) {
1859   Record.push_back((uint64_t)N->isDistinct());
1860   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1861   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1862   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1863   Record.push_back(N->getLine());
1864 
1865   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
1866   Record.clear();
1867 }
1868 
1869 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
1870                                             SmallVectorImpl<uint64_t> &Record,
1871                                             unsigned Abbrev) {
1872   Record.reserve(N->getElements().size() + 1);
1873   const uint64_t Version = 3 << 1;
1874   Record.push_back((uint64_t)N->isDistinct() | Version);
1875   Record.append(N->elements_begin(), N->elements_end());
1876 
1877   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
1878   Record.clear();
1879 }
1880 
1881 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
1882     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
1883     unsigned Abbrev) {
1884   Record.push_back(N->isDistinct());
1885   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
1886   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
1887 
1888   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
1889   Record.clear();
1890 }
1891 
1892 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
1893                                               SmallVectorImpl<uint64_t> &Record,
1894                                               unsigned Abbrev) {
1895   Record.push_back(N->isDistinct());
1896   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1897   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1898   Record.push_back(N->getLine());
1899   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
1900   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
1901   Record.push_back(N->getAttributes());
1902   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1903 
1904   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
1905   Record.clear();
1906 }
1907 
1908 void ModuleBitcodeWriter::writeDIImportedEntity(
1909     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
1910     unsigned Abbrev) {
1911   Record.push_back(N->isDistinct());
1912   Record.push_back(N->getTag());
1913   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1914   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
1915   Record.push_back(N->getLine());
1916   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1917   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
1918 
1919   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
1920   Record.clear();
1921 }
1922 
1923 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
1924   auto Abbv = std::make_shared<BitCodeAbbrev>();
1925   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
1926   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1927   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1928   return Stream.EmitAbbrev(std::move(Abbv));
1929 }
1930 
1931 void ModuleBitcodeWriter::writeNamedMetadata(
1932     SmallVectorImpl<uint64_t> &Record) {
1933   if (M.named_metadata_empty())
1934     return;
1935 
1936   unsigned Abbrev = createNamedMetadataAbbrev();
1937   for (const NamedMDNode &NMD : M.named_metadata()) {
1938     // Write name.
1939     StringRef Str = NMD.getName();
1940     Record.append(Str.bytes_begin(), Str.bytes_end());
1941     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
1942     Record.clear();
1943 
1944     // Write named metadata operands.
1945     for (const MDNode *N : NMD.operands())
1946       Record.push_back(VE.getMetadataID(N));
1947     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
1948     Record.clear();
1949   }
1950 }
1951 
1952 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
1953   auto Abbv = std::make_shared<BitCodeAbbrev>();
1954   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
1955   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
1956   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
1957   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
1958   return Stream.EmitAbbrev(std::move(Abbv));
1959 }
1960 
1961 /// Write out a record for MDString.
1962 ///
1963 /// All the metadata strings in a metadata block are emitted in a single
1964 /// record.  The sizes and strings themselves are shoved into a blob.
1965 void ModuleBitcodeWriter::writeMetadataStrings(
1966     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
1967   if (Strings.empty())
1968     return;
1969 
1970   // Start the record with the number of strings.
1971   Record.push_back(bitc::METADATA_STRINGS);
1972   Record.push_back(Strings.size());
1973 
1974   // Emit the sizes of the strings in the blob.
1975   SmallString<256> Blob;
1976   {
1977     BitstreamWriter W(Blob);
1978     for (const Metadata *MD : Strings)
1979       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
1980     W.FlushToWord();
1981   }
1982 
1983   // Add the offset to the strings to the record.
1984   Record.push_back(Blob.size());
1985 
1986   // Add the strings to the blob.
1987   for (const Metadata *MD : Strings)
1988     Blob.append(cast<MDString>(MD)->getString());
1989 
1990   // Emit the final record.
1991   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
1992   Record.clear();
1993 }
1994 
1995 // Generates an enum to use as an index in the Abbrev array of Metadata record.
1996 enum MetadataAbbrev : unsigned {
1997 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
1998 #include "llvm/IR/Metadata.def"
1999   LastPlusOne
2000 };
2001 
2002 void ModuleBitcodeWriter::writeMetadataRecords(
2003     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2004     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2005   if (MDs.empty())
2006     return;
2007 
2008   // Initialize MDNode abbreviations.
2009 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2010 #include "llvm/IR/Metadata.def"
2011 
2012   for (const Metadata *MD : MDs) {
2013     if (IndexPos)
2014       IndexPos->push_back(Stream.GetCurrentBitNo());
2015     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2016       assert(N->isResolved() && "Expected forward references to be resolved");
2017 
2018       switch (N->getMetadataID()) {
2019       default:
2020         llvm_unreachable("Invalid MDNode subclass");
2021 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2022   case Metadata::CLASS##Kind:                                                  \
2023     if (MDAbbrevs)                                                             \
2024       write##CLASS(cast<CLASS>(N), Record,                                     \
2025                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2026     else                                                                       \
2027       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2028     continue;
2029 #include "llvm/IR/Metadata.def"
2030       }
2031     }
2032     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2033   }
2034 }
2035 
2036 void ModuleBitcodeWriter::writeModuleMetadata() {
2037   if (!VE.hasMDs() && M.named_metadata_empty())
2038     return;
2039 
2040   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2041   SmallVector<uint64_t, 64> Record;
2042 
2043   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2044   // block and load any metadata.
2045   std::vector<unsigned> MDAbbrevs;
2046 
2047   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2048   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2049   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2050       createGenericDINodeAbbrev();
2051 
2052   auto Abbv = std::make_shared<BitCodeAbbrev>();
2053   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2054   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2055   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2056   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2057 
2058   Abbv = std::make_shared<BitCodeAbbrev>();
2059   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2060   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2061   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2062   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2063 
2064   // Emit MDStrings together upfront.
2065   writeMetadataStrings(VE.getMDStrings(), Record);
2066 
2067   // We only emit an index for the metadata record if we have more than a given
2068   // (naive) threshold of metadatas, otherwise it is not worth it.
2069   if (VE.getNonMDStrings().size() > IndexThreshold) {
2070     // Write a placeholder value in for the offset of the metadata index,
2071     // which is written after the records, so that it can include
2072     // the offset of each entry. The placeholder offset will be
2073     // updated after all records are emitted.
2074     uint64_t Vals[] = {0, 0};
2075     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2076   }
2077 
2078   // Compute and save the bit offset to the current position, which will be
2079   // patched when we emit the index later. We can simply subtract the 64-bit
2080   // fixed size from the current bit number to get the location to backpatch.
2081   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2082 
2083   // This index will contain the bitpos for each individual record.
2084   std::vector<uint64_t> IndexPos;
2085   IndexPos.reserve(VE.getNonMDStrings().size());
2086 
2087   // Write all the records
2088   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2089 
2090   if (VE.getNonMDStrings().size() > IndexThreshold) {
2091     // Now that we have emitted all the records we will emit the index. But
2092     // first
2093     // backpatch the forward reference so that the reader can skip the records
2094     // efficiently.
2095     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2096                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2097 
2098     // Delta encode the index.
2099     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2100     for (auto &Elt : IndexPos) {
2101       auto EltDelta = Elt - PreviousValue;
2102       PreviousValue = Elt;
2103       Elt = EltDelta;
2104     }
2105     // Emit the index record.
2106     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2107     IndexPos.clear();
2108   }
2109 
2110   // Write the named metadata now.
2111   writeNamedMetadata(Record);
2112 
2113   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2114     SmallVector<uint64_t, 4> Record;
2115     Record.push_back(VE.getValueID(&GO));
2116     pushGlobalMetadataAttachment(Record, GO);
2117     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2118   };
2119   for (const Function &F : M)
2120     if (F.isDeclaration() && F.hasMetadata())
2121       AddDeclAttachedMetadata(F);
2122   // FIXME: Only store metadata for declarations here, and move data for global
2123   // variable definitions to a separate block (PR28134).
2124   for (const GlobalVariable &GV : M.globals())
2125     if (GV.hasMetadata())
2126       AddDeclAttachedMetadata(GV);
2127 
2128   Stream.ExitBlock();
2129 }
2130 
2131 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2132   if (!VE.hasMDs())
2133     return;
2134 
2135   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2136   SmallVector<uint64_t, 64> Record;
2137   writeMetadataStrings(VE.getMDStrings(), Record);
2138   writeMetadataRecords(VE.getNonMDStrings(), Record);
2139   Stream.ExitBlock();
2140 }
2141 
2142 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2143     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2144   // [n x [id, mdnode]]
2145   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2146   GO.getAllMetadata(MDs);
2147   for (const auto &I : MDs) {
2148     Record.push_back(I.first);
2149     Record.push_back(VE.getMetadataID(I.second));
2150   }
2151 }
2152 
2153 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2154   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2155 
2156   SmallVector<uint64_t, 64> Record;
2157 
2158   if (F.hasMetadata()) {
2159     pushGlobalMetadataAttachment(Record, F);
2160     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2161     Record.clear();
2162   }
2163 
2164   // Write metadata attachments
2165   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2166   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2167   for (const BasicBlock &BB : F)
2168     for (const Instruction &I : BB) {
2169       MDs.clear();
2170       I.getAllMetadataOtherThanDebugLoc(MDs);
2171 
2172       // If no metadata, ignore instruction.
2173       if (MDs.empty()) continue;
2174 
2175       Record.push_back(VE.getInstructionID(&I));
2176 
2177       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2178         Record.push_back(MDs[i].first);
2179         Record.push_back(VE.getMetadataID(MDs[i].second));
2180       }
2181       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2182       Record.clear();
2183     }
2184 
2185   Stream.ExitBlock();
2186 }
2187 
2188 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2189   SmallVector<uint64_t, 64> Record;
2190 
2191   // Write metadata kinds
2192   // METADATA_KIND - [n x [id, name]]
2193   SmallVector<StringRef, 8> Names;
2194   M.getMDKindNames(Names);
2195 
2196   if (Names.empty()) return;
2197 
2198   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2199 
2200   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2201     Record.push_back(MDKindID);
2202     StringRef KName = Names[MDKindID];
2203     Record.append(KName.begin(), KName.end());
2204 
2205     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2206     Record.clear();
2207   }
2208 
2209   Stream.ExitBlock();
2210 }
2211 
2212 void ModuleBitcodeWriter::writeOperandBundleTags() {
2213   // Write metadata kinds
2214   //
2215   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2216   //
2217   // OPERAND_BUNDLE_TAG - [strchr x N]
2218 
2219   SmallVector<StringRef, 8> Tags;
2220   M.getOperandBundleTags(Tags);
2221 
2222   if (Tags.empty())
2223     return;
2224 
2225   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2226 
2227   SmallVector<uint64_t, 64> Record;
2228 
2229   for (auto Tag : Tags) {
2230     Record.append(Tag.begin(), Tag.end());
2231 
2232     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2233     Record.clear();
2234   }
2235 
2236   Stream.ExitBlock();
2237 }
2238 
2239 void ModuleBitcodeWriter::writeSyncScopeNames() {
2240   SmallVector<StringRef, 8> SSNs;
2241   M.getContext().getSyncScopeNames(SSNs);
2242   if (SSNs.empty())
2243     return;
2244 
2245   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2246 
2247   SmallVector<uint64_t, 64> Record;
2248   for (auto SSN : SSNs) {
2249     Record.append(SSN.begin(), SSN.end());
2250     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2251     Record.clear();
2252   }
2253 
2254   Stream.ExitBlock();
2255 }
2256 
2257 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
2258   if ((int64_t)V >= 0)
2259     Vals.push_back(V << 1);
2260   else
2261     Vals.push_back((-V << 1) | 1);
2262 }
2263 
2264 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2265                                          bool isGlobal) {
2266   if (FirstVal == LastVal) return;
2267 
2268   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2269 
2270   unsigned AggregateAbbrev = 0;
2271   unsigned String8Abbrev = 0;
2272   unsigned CString7Abbrev = 0;
2273   unsigned CString6Abbrev = 0;
2274   // If this is a constant pool for the module, emit module-specific abbrevs.
2275   if (isGlobal) {
2276     // Abbrev for CST_CODE_AGGREGATE.
2277     auto Abbv = std::make_shared<BitCodeAbbrev>();
2278     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2279     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2280     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2281     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2282 
2283     // Abbrev for CST_CODE_STRING.
2284     Abbv = std::make_shared<BitCodeAbbrev>();
2285     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2286     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2287     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2288     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2289     // Abbrev for CST_CODE_CSTRING.
2290     Abbv = std::make_shared<BitCodeAbbrev>();
2291     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2292     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2293     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2294     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2295     // Abbrev for CST_CODE_CSTRING.
2296     Abbv = std::make_shared<BitCodeAbbrev>();
2297     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2298     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2299     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2300     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2301   }
2302 
2303   SmallVector<uint64_t, 64> Record;
2304 
2305   const ValueEnumerator::ValueList &Vals = VE.getValues();
2306   Type *LastTy = nullptr;
2307   for (unsigned i = FirstVal; i != LastVal; ++i) {
2308     const Value *V = Vals[i].first;
2309     // If we need to switch types, do so now.
2310     if (V->getType() != LastTy) {
2311       LastTy = V->getType();
2312       Record.push_back(VE.getTypeID(LastTy));
2313       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2314                         CONSTANTS_SETTYPE_ABBREV);
2315       Record.clear();
2316     }
2317 
2318     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2319       Record.push_back(unsigned(IA->hasSideEffects()) |
2320                        unsigned(IA->isAlignStack()) << 1 |
2321                        unsigned(IA->getDialect()&1) << 2);
2322 
2323       // Add the asm string.
2324       const std::string &AsmStr = IA->getAsmString();
2325       Record.push_back(AsmStr.size());
2326       Record.append(AsmStr.begin(), AsmStr.end());
2327 
2328       // Add the constraint string.
2329       const std::string &ConstraintStr = IA->getConstraintString();
2330       Record.push_back(ConstraintStr.size());
2331       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2332       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2333       Record.clear();
2334       continue;
2335     }
2336     const Constant *C = cast<Constant>(V);
2337     unsigned Code = -1U;
2338     unsigned AbbrevToUse = 0;
2339     if (C->isNullValue()) {
2340       Code = bitc::CST_CODE_NULL;
2341     } else if (isa<UndefValue>(C)) {
2342       Code = bitc::CST_CODE_UNDEF;
2343     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2344       if (IV->getBitWidth() <= 64) {
2345         uint64_t V = IV->getSExtValue();
2346         emitSignedInt64(Record, V);
2347         Code = bitc::CST_CODE_INTEGER;
2348         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2349       } else {                             // Wide integers, > 64 bits in size.
2350         // We have an arbitrary precision integer value to write whose
2351         // bit width is > 64. However, in canonical unsigned integer
2352         // format it is likely that the high bits are going to be zero.
2353         // So, we only write the number of active words.
2354         unsigned NWords = IV->getValue().getActiveWords();
2355         const uint64_t *RawWords = IV->getValue().getRawData();
2356         for (unsigned i = 0; i != NWords; ++i) {
2357           emitSignedInt64(Record, RawWords[i]);
2358         }
2359         Code = bitc::CST_CODE_WIDE_INTEGER;
2360       }
2361     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2362       Code = bitc::CST_CODE_FLOAT;
2363       Type *Ty = CFP->getType();
2364       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
2365         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2366       } else if (Ty->isX86_FP80Ty()) {
2367         // api needed to prevent premature destruction
2368         // bits are not in the same order as a normal i80 APInt, compensate.
2369         APInt api = CFP->getValueAPF().bitcastToAPInt();
2370         const uint64_t *p = api.getRawData();
2371         Record.push_back((p[1] << 48) | (p[0] >> 16));
2372         Record.push_back(p[0] & 0xffffLL);
2373       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2374         APInt api = CFP->getValueAPF().bitcastToAPInt();
2375         const uint64_t *p = api.getRawData();
2376         Record.push_back(p[0]);
2377         Record.push_back(p[1]);
2378       } else {
2379         assert(0 && "Unknown FP type!");
2380       }
2381     } else if (isa<ConstantDataSequential>(C) &&
2382                cast<ConstantDataSequential>(C)->isString()) {
2383       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2384       // Emit constant strings specially.
2385       unsigned NumElts = Str->getNumElements();
2386       // If this is a null-terminated string, use the denser CSTRING encoding.
2387       if (Str->isCString()) {
2388         Code = bitc::CST_CODE_CSTRING;
2389         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2390       } else {
2391         Code = bitc::CST_CODE_STRING;
2392         AbbrevToUse = String8Abbrev;
2393       }
2394       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2395       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2396       for (unsigned i = 0; i != NumElts; ++i) {
2397         unsigned char V = Str->getElementAsInteger(i);
2398         Record.push_back(V);
2399         isCStr7 &= (V & 128) == 0;
2400         if (isCStrChar6)
2401           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2402       }
2403 
2404       if (isCStrChar6)
2405         AbbrevToUse = CString6Abbrev;
2406       else if (isCStr7)
2407         AbbrevToUse = CString7Abbrev;
2408     } else if (const ConstantDataSequential *CDS =
2409                   dyn_cast<ConstantDataSequential>(C)) {
2410       Code = bitc::CST_CODE_DATA;
2411       Type *EltTy = CDS->getType()->getElementType();
2412       if (isa<IntegerType>(EltTy)) {
2413         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2414           Record.push_back(CDS->getElementAsInteger(i));
2415       } else {
2416         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2417           Record.push_back(
2418               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2419       }
2420     } else if (isa<ConstantAggregate>(C)) {
2421       Code = bitc::CST_CODE_AGGREGATE;
2422       for (const Value *Op : C->operands())
2423         Record.push_back(VE.getValueID(Op));
2424       AbbrevToUse = AggregateAbbrev;
2425     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2426       switch (CE->getOpcode()) {
2427       default:
2428         if (Instruction::isCast(CE->getOpcode())) {
2429           Code = bitc::CST_CODE_CE_CAST;
2430           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2431           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2432           Record.push_back(VE.getValueID(C->getOperand(0)));
2433           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2434         } else {
2435           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2436           Code = bitc::CST_CODE_CE_BINOP;
2437           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2438           Record.push_back(VE.getValueID(C->getOperand(0)));
2439           Record.push_back(VE.getValueID(C->getOperand(1)));
2440           uint64_t Flags = getOptimizationFlags(CE);
2441           if (Flags != 0)
2442             Record.push_back(Flags);
2443         }
2444         break;
2445       case Instruction::FNeg: {
2446         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2447         Code = bitc::CST_CODE_CE_UNOP;
2448         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2449         Record.push_back(VE.getValueID(C->getOperand(0)));
2450         uint64_t Flags = getOptimizationFlags(CE);
2451         if (Flags != 0)
2452           Record.push_back(Flags);
2453         break;
2454       }
2455       case Instruction::GetElementPtr: {
2456         Code = bitc::CST_CODE_CE_GEP;
2457         const auto *GO = cast<GEPOperator>(C);
2458         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2459         if (Optional<unsigned> Idx = GO->getInRangeIndex()) {
2460           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2461           Record.push_back((*Idx << 1) | GO->isInBounds());
2462         } else if (GO->isInBounds())
2463           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2464         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2465           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2466           Record.push_back(VE.getValueID(C->getOperand(i)));
2467         }
2468         break;
2469       }
2470       case Instruction::Select:
2471         Code = bitc::CST_CODE_CE_SELECT;
2472         Record.push_back(VE.getValueID(C->getOperand(0)));
2473         Record.push_back(VE.getValueID(C->getOperand(1)));
2474         Record.push_back(VE.getValueID(C->getOperand(2)));
2475         break;
2476       case Instruction::ExtractElement:
2477         Code = bitc::CST_CODE_CE_EXTRACTELT;
2478         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2479         Record.push_back(VE.getValueID(C->getOperand(0)));
2480         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2481         Record.push_back(VE.getValueID(C->getOperand(1)));
2482         break;
2483       case Instruction::InsertElement:
2484         Code = bitc::CST_CODE_CE_INSERTELT;
2485         Record.push_back(VE.getValueID(C->getOperand(0)));
2486         Record.push_back(VE.getValueID(C->getOperand(1)));
2487         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2488         Record.push_back(VE.getValueID(C->getOperand(2)));
2489         break;
2490       case Instruction::ShuffleVector:
2491         // If the return type and argument types are the same, this is a
2492         // standard shufflevector instruction.  If the types are different,
2493         // then the shuffle is widening or truncating the input vectors, and
2494         // the argument type must also be encoded.
2495         if (C->getType() == C->getOperand(0)->getType()) {
2496           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2497         } else {
2498           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2499           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2500         }
2501         Record.push_back(VE.getValueID(C->getOperand(0)));
2502         Record.push_back(VE.getValueID(C->getOperand(1)));
2503         Record.push_back(VE.getValueID(C->getOperand(2)));
2504         break;
2505       case Instruction::ICmp:
2506       case Instruction::FCmp:
2507         Code = bitc::CST_CODE_CE_CMP;
2508         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2509         Record.push_back(VE.getValueID(C->getOperand(0)));
2510         Record.push_back(VE.getValueID(C->getOperand(1)));
2511         Record.push_back(CE->getPredicate());
2512         break;
2513       }
2514     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2515       Code = bitc::CST_CODE_BLOCKADDRESS;
2516       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2517       Record.push_back(VE.getValueID(BA->getFunction()));
2518       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2519     } else {
2520 #ifndef NDEBUG
2521       C->dump();
2522 #endif
2523       llvm_unreachable("Unknown constant!");
2524     }
2525     Stream.EmitRecord(Code, Record, AbbrevToUse);
2526     Record.clear();
2527   }
2528 
2529   Stream.ExitBlock();
2530 }
2531 
2532 void ModuleBitcodeWriter::writeModuleConstants() {
2533   const ValueEnumerator::ValueList &Vals = VE.getValues();
2534 
2535   // Find the first constant to emit, which is the first non-globalvalue value.
2536   // We know globalvalues have been emitted by WriteModuleInfo.
2537   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2538     if (!isa<GlobalValue>(Vals[i].first)) {
2539       writeConstants(i, Vals.size(), true);
2540       return;
2541     }
2542   }
2543 }
2544 
2545 /// pushValueAndType - The file has to encode both the value and type id for
2546 /// many values, because we need to know what type to create for forward
2547 /// references.  However, most operands are not forward references, so this type
2548 /// field is not needed.
2549 ///
2550 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2551 /// instruction ID, then it is a forward reference, and it also includes the
2552 /// type ID.  The value ID that is written is encoded relative to the InstID.
2553 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2554                                            SmallVectorImpl<unsigned> &Vals) {
2555   unsigned ValID = VE.getValueID(V);
2556   // Make encoding relative to the InstID.
2557   Vals.push_back(InstID - ValID);
2558   if (ValID >= InstID) {
2559     Vals.push_back(VE.getTypeID(V->getType()));
2560     return true;
2561   }
2562   return false;
2563 }
2564 
2565 void ModuleBitcodeWriter::writeOperandBundles(ImmutableCallSite CS,
2566                                               unsigned InstID) {
2567   SmallVector<unsigned, 64> Record;
2568   LLVMContext &C = CS.getInstruction()->getContext();
2569 
2570   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2571     const auto &Bundle = CS.getOperandBundleAt(i);
2572     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2573 
2574     for (auto &Input : Bundle.Inputs)
2575       pushValueAndType(Input, InstID, Record);
2576 
2577     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2578     Record.clear();
2579   }
2580 }
2581 
2582 /// pushValue - Like pushValueAndType, but where the type of the value is
2583 /// omitted (perhaps it was already encoded in an earlier operand).
2584 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2585                                     SmallVectorImpl<unsigned> &Vals) {
2586   unsigned ValID = VE.getValueID(V);
2587   Vals.push_back(InstID - ValID);
2588 }
2589 
2590 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2591                                           SmallVectorImpl<uint64_t> &Vals) {
2592   unsigned ValID = VE.getValueID(V);
2593   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2594   emitSignedInt64(Vals, diff);
2595 }
2596 
2597 /// WriteInstruction - Emit an instruction to the specified stream.
2598 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2599                                            unsigned InstID,
2600                                            SmallVectorImpl<unsigned> &Vals) {
2601   unsigned Code = 0;
2602   unsigned AbbrevToUse = 0;
2603   VE.setInstructionID(&I);
2604   switch (I.getOpcode()) {
2605   default:
2606     if (Instruction::isCast(I.getOpcode())) {
2607       Code = bitc::FUNC_CODE_INST_CAST;
2608       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2609         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2610       Vals.push_back(VE.getTypeID(I.getType()));
2611       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2612     } else {
2613       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2614       Code = bitc::FUNC_CODE_INST_BINOP;
2615       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2616         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2617       pushValue(I.getOperand(1), InstID, Vals);
2618       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2619       uint64_t Flags = getOptimizationFlags(&I);
2620       if (Flags != 0) {
2621         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2622           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2623         Vals.push_back(Flags);
2624       }
2625     }
2626     break;
2627   case Instruction::FNeg: {
2628     Code = bitc::FUNC_CODE_INST_UNOP;
2629     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2630       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
2631     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
2632     uint64_t Flags = getOptimizationFlags(&I);
2633     if (Flags != 0) {
2634       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
2635         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
2636       Vals.push_back(Flags);
2637     }
2638     break;
2639   }
2640   case Instruction::GetElementPtr: {
2641     Code = bitc::FUNC_CODE_INST_GEP;
2642     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2643     auto &GEPInst = cast<GetElementPtrInst>(I);
2644     Vals.push_back(GEPInst.isInBounds());
2645     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2646     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2647       pushValueAndType(I.getOperand(i), InstID, Vals);
2648     break;
2649   }
2650   case Instruction::ExtractValue: {
2651     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2652     pushValueAndType(I.getOperand(0), InstID, Vals);
2653     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2654     Vals.append(EVI->idx_begin(), EVI->idx_end());
2655     break;
2656   }
2657   case Instruction::InsertValue: {
2658     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2659     pushValueAndType(I.getOperand(0), InstID, Vals);
2660     pushValueAndType(I.getOperand(1), InstID, Vals);
2661     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2662     Vals.append(IVI->idx_begin(), IVI->idx_end());
2663     break;
2664   }
2665   case Instruction::Select: {
2666     Code = bitc::FUNC_CODE_INST_VSELECT;
2667     pushValueAndType(I.getOperand(1), InstID, Vals);
2668     pushValue(I.getOperand(2), InstID, Vals);
2669     pushValueAndType(I.getOperand(0), InstID, Vals);
2670     uint64_t Flags = getOptimizationFlags(&I);
2671     if (Flags != 0)
2672       Vals.push_back(Flags);
2673     break;
2674   }
2675   case Instruction::ExtractElement:
2676     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2677     pushValueAndType(I.getOperand(0), InstID, Vals);
2678     pushValueAndType(I.getOperand(1), InstID, Vals);
2679     break;
2680   case Instruction::InsertElement:
2681     Code = bitc::FUNC_CODE_INST_INSERTELT;
2682     pushValueAndType(I.getOperand(0), InstID, Vals);
2683     pushValue(I.getOperand(1), InstID, Vals);
2684     pushValueAndType(I.getOperand(2), InstID, Vals);
2685     break;
2686   case Instruction::ShuffleVector:
2687     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2688     pushValueAndType(I.getOperand(0), InstID, Vals);
2689     pushValue(I.getOperand(1), InstID, Vals);
2690     pushValue(I.getOperand(2), InstID, Vals);
2691     break;
2692   case Instruction::ICmp:
2693   case Instruction::FCmp: {
2694     // compare returning Int1Ty or vector of Int1Ty
2695     Code = bitc::FUNC_CODE_INST_CMP2;
2696     pushValueAndType(I.getOperand(0), InstID, Vals);
2697     pushValue(I.getOperand(1), InstID, Vals);
2698     Vals.push_back(cast<CmpInst>(I).getPredicate());
2699     uint64_t Flags = getOptimizationFlags(&I);
2700     if (Flags != 0)
2701       Vals.push_back(Flags);
2702     break;
2703   }
2704 
2705   case Instruction::Ret:
2706     {
2707       Code = bitc::FUNC_CODE_INST_RET;
2708       unsigned NumOperands = I.getNumOperands();
2709       if (NumOperands == 0)
2710         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2711       else if (NumOperands == 1) {
2712         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2713           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2714       } else {
2715         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2716           pushValueAndType(I.getOperand(i), InstID, Vals);
2717       }
2718     }
2719     break;
2720   case Instruction::Br:
2721     {
2722       Code = bitc::FUNC_CODE_INST_BR;
2723       const BranchInst &II = cast<BranchInst>(I);
2724       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2725       if (II.isConditional()) {
2726         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2727         pushValue(II.getCondition(), InstID, Vals);
2728       }
2729     }
2730     break;
2731   case Instruction::Switch:
2732     {
2733       Code = bitc::FUNC_CODE_INST_SWITCH;
2734       const SwitchInst &SI = cast<SwitchInst>(I);
2735       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2736       pushValue(SI.getCondition(), InstID, Vals);
2737       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2738       for (auto Case : SI.cases()) {
2739         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2740         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2741       }
2742     }
2743     break;
2744   case Instruction::IndirectBr:
2745     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2746     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2747     // Encode the address operand as relative, but not the basic blocks.
2748     pushValue(I.getOperand(0), InstID, Vals);
2749     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2750       Vals.push_back(VE.getValueID(I.getOperand(i)));
2751     break;
2752 
2753   case Instruction::Invoke: {
2754     const InvokeInst *II = cast<InvokeInst>(&I);
2755     const Value *Callee = II->getCalledValue();
2756     FunctionType *FTy = II->getFunctionType();
2757 
2758     if (II->hasOperandBundles())
2759       writeOperandBundles(II, InstID);
2760 
2761     Code = bitc::FUNC_CODE_INST_INVOKE;
2762 
2763     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
2764     Vals.push_back(II->getCallingConv() | 1 << 13);
2765     Vals.push_back(VE.getValueID(II->getNormalDest()));
2766     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2767     Vals.push_back(VE.getTypeID(FTy));
2768     pushValueAndType(Callee, InstID, Vals);
2769 
2770     // Emit value #'s for the fixed parameters.
2771     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2772       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2773 
2774     // Emit type/value pairs for varargs params.
2775     if (FTy->isVarArg()) {
2776       for (unsigned i = FTy->getNumParams(), e = II->getNumArgOperands();
2777            i != e; ++i)
2778         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2779     }
2780     break;
2781   }
2782   case Instruction::Resume:
2783     Code = bitc::FUNC_CODE_INST_RESUME;
2784     pushValueAndType(I.getOperand(0), InstID, Vals);
2785     break;
2786   case Instruction::CleanupRet: {
2787     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2788     const auto &CRI = cast<CleanupReturnInst>(I);
2789     pushValue(CRI.getCleanupPad(), InstID, Vals);
2790     if (CRI.hasUnwindDest())
2791       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2792     break;
2793   }
2794   case Instruction::CatchRet: {
2795     Code = bitc::FUNC_CODE_INST_CATCHRET;
2796     const auto &CRI = cast<CatchReturnInst>(I);
2797     pushValue(CRI.getCatchPad(), InstID, Vals);
2798     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2799     break;
2800   }
2801   case Instruction::CleanupPad:
2802   case Instruction::CatchPad: {
2803     const auto &FuncletPad = cast<FuncletPadInst>(I);
2804     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2805                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2806     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2807 
2808     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2809     Vals.push_back(NumArgOperands);
2810     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2811       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2812     break;
2813   }
2814   case Instruction::CatchSwitch: {
2815     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2816     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2817 
2818     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2819 
2820     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2821     Vals.push_back(NumHandlers);
2822     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2823       Vals.push_back(VE.getValueID(CatchPadBB));
2824 
2825     if (CatchSwitch.hasUnwindDest())
2826       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
2827     break;
2828   }
2829   case Instruction::CallBr: {
2830     const CallBrInst *CBI = cast<CallBrInst>(&I);
2831     const Value *Callee = CBI->getCalledValue();
2832     FunctionType *FTy = CBI->getFunctionType();
2833 
2834     if (CBI->hasOperandBundles())
2835       writeOperandBundles(CBI, InstID);
2836 
2837     Code = bitc::FUNC_CODE_INST_CALLBR;
2838 
2839     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
2840 
2841     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
2842                    1 << bitc::CALL_EXPLICIT_TYPE);
2843 
2844     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
2845     Vals.push_back(CBI->getNumIndirectDests());
2846     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
2847       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
2848 
2849     Vals.push_back(VE.getTypeID(FTy));
2850     pushValueAndType(Callee, InstID, Vals);
2851 
2852     // Emit value #'s for the fixed parameters.
2853     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2854       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2855 
2856     // Emit type/value pairs for varargs params.
2857     if (FTy->isVarArg()) {
2858       for (unsigned i = FTy->getNumParams(), e = CBI->getNumArgOperands();
2859            i != e; ++i)
2860         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2861     }
2862     break;
2863   }
2864   case Instruction::Unreachable:
2865     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
2866     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
2867     break;
2868 
2869   case Instruction::PHI: {
2870     const PHINode &PN = cast<PHINode>(I);
2871     Code = bitc::FUNC_CODE_INST_PHI;
2872     // With the newer instruction encoding, forward references could give
2873     // negative valued IDs.  This is most common for PHIs, so we use
2874     // signed VBRs.
2875     SmallVector<uint64_t, 128> Vals64;
2876     Vals64.push_back(VE.getTypeID(PN.getType()));
2877     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
2878       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
2879       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
2880     }
2881     // Emit a Vals64 vector and exit.
2882     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
2883     Vals64.clear();
2884     return;
2885   }
2886 
2887   case Instruction::LandingPad: {
2888     const LandingPadInst &LP = cast<LandingPadInst>(I);
2889     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
2890     Vals.push_back(VE.getTypeID(LP.getType()));
2891     Vals.push_back(LP.isCleanup());
2892     Vals.push_back(LP.getNumClauses());
2893     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
2894       if (LP.isCatch(I))
2895         Vals.push_back(LandingPadInst::Catch);
2896       else
2897         Vals.push_back(LandingPadInst::Filter);
2898       pushValueAndType(LP.getClause(I), InstID, Vals);
2899     }
2900     break;
2901   }
2902 
2903   case Instruction::Alloca: {
2904     Code = bitc::FUNC_CODE_INST_ALLOCA;
2905     const AllocaInst &AI = cast<AllocaInst>(I);
2906     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
2907     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2908     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
2909     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
2910     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
2911            "not enough bits for maximum alignment");
2912     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
2913     AlignRecord |= AI.isUsedWithInAlloca() << 5;
2914     AlignRecord |= 1 << 6;
2915     AlignRecord |= AI.isSwiftError() << 7;
2916     Vals.push_back(AlignRecord);
2917     break;
2918   }
2919 
2920   case Instruction::Load:
2921     if (cast<LoadInst>(I).isAtomic()) {
2922       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
2923       pushValueAndType(I.getOperand(0), InstID, Vals);
2924     } else {
2925       Code = bitc::FUNC_CODE_INST_LOAD;
2926       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
2927         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
2928     }
2929     Vals.push_back(VE.getTypeID(I.getType()));
2930     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
2931     Vals.push_back(cast<LoadInst>(I).isVolatile());
2932     if (cast<LoadInst>(I).isAtomic()) {
2933       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
2934       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
2935     }
2936     break;
2937   case Instruction::Store:
2938     if (cast<StoreInst>(I).isAtomic())
2939       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
2940     else
2941       Code = bitc::FUNC_CODE_INST_STORE;
2942     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
2943     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
2944     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
2945     Vals.push_back(cast<StoreInst>(I).isVolatile());
2946     if (cast<StoreInst>(I).isAtomic()) {
2947       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
2948       Vals.push_back(
2949           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
2950     }
2951     break;
2952   case Instruction::AtomicCmpXchg:
2953     Code = bitc::FUNC_CODE_INST_CMPXCHG;
2954     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
2955     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
2956     pushValue(I.getOperand(2), InstID, Vals);        // newval.
2957     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
2958     Vals.push_back(
2959         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
2960     Vals.push_back(
2961         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
2962     Vals.push_back(
2963         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
2964     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
2965     break;
2966   case Instruction::AtomicRMW:
2967     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
2968     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
2969     pushValue(I.getOperand(1), InstID, Vals);        // val.
2970     Vals.push_back(
2971         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
2972     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
2973     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
2974     Vals.push_back(
2975         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
2976     break;
2977   case Instruction::Fence:
2978     Code = bitc::FUNC_CODE_INST_FENCE;
2979     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
2980     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
2981     break;
2982   case Instruction::Call: {
2983     const CallInst &CI = cast<CallInst>(I);
2984     FunctionType *FTy = CI.getFunctionType();
2985 
2986     if (CI.hasOperandBundles())
2987       writeOperandBundles(&CI, InstID);
2988 
2989     Code = bitc::FUNC_CODE_INST_CALL;
2990 
2991     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
2992 
2993     unsigned Flags = getOptimizationFlags(&I);
2994     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
2995                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
2996                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
2997                    1 << bitc::CALL_EXPLICIT_TYPE |
2998                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
2999                    unsigned(Flags != 0) << bitc::CALL_FMF);
3000     if (Flags != 0)
3001       Vals.push_back(Flags);
3002 
3003     Vals.push_back(VE.getTypeID(FTy));
3004     pushValueAndType(CI.getCalledValue(), InstID, Vals); // Callee
3005 
3006     // Emit value #'s for the fixed parameters.
3007     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3008       // Check for labels (can happen with asm labels).
3009       if (FTy->getParamType(i)->isLabelTy())
3010         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3011       else
3012         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3013     }
3014 
3015     // Emit type/value pairs for varargs params.
3016     if (FTy->isVarArg()) {
3017       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
3018            i != e; ++i)
3019         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3020     }
3021     break;
3022   }
3023   case Instruction::VAArg:
3024     Code = bitc::FUNC_CODE_INST_VAARG;
3025     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3026     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3027     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3028     break;
3029   }
3030 
3031   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3032   Vals.clear();
3033 }
3034 
3035 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3036 /// to allow clients to efficiently find the function body.
3037 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3038   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3039   // Get the offset of the VST we are writing, and backpatch it into
3040   // the VST forward declaration record.
3041   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3042   // The BitcodeStartBit was the stream offset of the identification block.
3043   VSTOffset -= bitcodeStartBit();
3044   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3045   // Note that we add 1 here because the offset is relative to one word
3046   // before the start of the identification block, which was historically
3047   // always the start of the regular bitcode header.
3048   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3049 
3050   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3051 
3052   auto Abbv = std::make_shared<BitCodeAbbrev>();
3053   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3054   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3055   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3056   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3057 
3058   for (const Function &F : M) {
3059     uint64_t Record[2];
3060 
3061     if (F.isDeclaration())
3062       continue;
3063 
3064     Record[0] = VE.getValueID(&F);
3065 
3066     // Save the word offset of the function (from the start of the
3067     // actual bitcode written to the stream).
3068     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3069     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3070     // Note that we add 1 here because the offset is relative to one word
3071     // before the start of the identification block, which was historically
3072     // always the start of the regular bitcode header.
3073     Record[1] = BitcodeIndex / 32 + 1;
3074 
3075     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3076   }
3077 
3078   Stream.ExitBlock();
3079 }
3080 
3081 /// Emit names for arguments, instructions and basic blocks in a function.
3082 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3083     const ValueSymbolTable &VST) {
3084   if (VST.empty())
3085     return;
3086 
3087   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3088 
3089   // FIXME: Set up the abbrev, we know how many values there are!
3090   // FIXME: We know if the type names can use 7-bit ascii.
3091   SmallVector<uint64_t, 64> NameVals;
3092 
3093   for (const ValueName &Name : VST) {
3094     // Figure out the encoding to use for the name.
3095     StringEncoding Bits = getStringEncoding(Name.getKey());
3096 
3097     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3098     NameVals.push_back(VE.getValueID(Name.getValue()));
3099 
3100     // VST_CODE_ENTRY:   [valueid, namechar x N]
3101     // VST_CODE_BBENTRY: [bbid, namechar x N]
3102     unsigned Code;
3103     if (isa<BasicBlock>(Name.getValue())) {
3104       Code = bitc::VST_CODE_BBENTRY;
3105       if (Bits == SE_Char6)
3106         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3107     } else {
3108       Code = bitc::VST_CODE_ENTRY;
3109       if (Bits == SE_Char6)
3110         AbbrevToUse = VST_ENTRY_6_ABBREV;
3111       else if (Bits == SE_Fixed7)
3112         AbbrevToUse = VST_ENTRY_7_ABBREV;
3113     }
3114 
3115     for (const auto P : Name.getKey())
3116       NameVals.push_back((unsigned char)P);
3117 
3118     // Emit the finished record.
3119     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3120     NameVals.clear();
3121   }
3122 
3123   Stream.ExitBlock();
3124 }
3125 
3126 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3127   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3128   unsigned Code;
3129   if (isa<BasicBlock>(Order.V))
3130     Code = bitc::USELIST_CODE_BB;
3131   else
3132     Code = bitc::USELIST_CODE_DEFAULT;
3133 
3134   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3135   Record.push_back(VE.getValueID(Order.V));
3136   Stream.EmitRecord(Code, Record);
3137 }
3138 
3139 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3140   assert(VE.shouldPreserveUseListOrder() &&
3141          "Expected to be preserving use-list order");
3142 
3143   auto hasMore = [&]() {
3144     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3145   };
3146   if (!hasMore())
3147     // Nothing to do.
3148     return;
3149 
3150   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3151   while (hasMore()) {
3152     writeUseList(std::move(VE.UseListOrders.back()));
3153     VE.UseListOrders.pop_back();
3154   }
3155   Stream.ExitBlock();
3156 }
3157 
3158 /// Emit a function body to the module stream.
3159 void ModuleBitcodeWriter::writeFunction(
3160     const Function &F,
3161     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3162   // Save the bitcode index of the start of this function block for recording
3163   // in the VST.
3164   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3165 
3166   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3167   VE.incorporateFunction(F);
3168 
3169   SmallVector<unsigned, 64> Vals;
3170 
3171   // Emit the number of basic blocks, so the reader can create them ahead of
3172   // time.
3173   Vals.push_back(VE.getBasicBlocks().size());
3174   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3175   Vals.clear();
3176 
3177   // If there are function-local constants, emit them now.
3178   unsigned CstStart, CstEnd;
3179   VE.getFunctionConstantRange(CstStart, CstEnd);
3180   writeConstants(CstStart, CstEnd, false);
3181 
3182   // If there is function-local metadata, emit it now.
3183   writeFunctionMetadata(F);
3184 
3185   // Keep a running idea of what the instruction ID is.
3186   unsigned InstID = CstEnd;
3187 
3188   bool NeedsMetadataAttachment = F.hasMetadata();
3189 
3190   DILocation *LastDL = nullptr;
3191   // Finally, emit all the instructions, in order.
3192   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
3193     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
3194          I != E; ++I) {
3195       writeInstruction(*I, InstID, Vals);
3196 
3197       if (!I->getType()->isVoidTy())
3198         ++InstID;
3199 
3200       // If the instruction has metadata, write a metadata attachment later.
3201       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
3202 
3203       // If the instruction has a debug location, emit it.
3204       DILocation *DL = I->getDebugLoc();
3205       if (!DL)
3206         continue;
3207 
3208       if (DL == LastDL) {
3209         // Just repeat the same debug loc as last time.
3210         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3211         continue;
3212       }
3213 
3214       Vals.push_back(DL->getLine());
3215       Vals.push_back(DL->getColumn());
3216       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3217       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3218       Vals.push_back(DL->isImplicitCode());
3219       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3220       Vals.clear();
3221 
3222       LastDL = DL;
3223     }
3224 
3225   // Emit names for all the instructions etc.
3226   if (auto *Symtab = F.getValueSymbolTable())
3227     writeFunctionLevelValueSymbolTable(*Symtab);
3228 
3229   if (NeedsMetadataAttachment)
3230     writeFunctionMetadataAttachment(F);
3231   if (VE.shouldPreserveUseListOrder())
3232     writeUseListBlock(&F);
3233   VE.purgeFunction();
3234   Stream.ExitBlock();
3235 }
3236 
3237 // Emit blockinfo, which defines the standard abbreviations etc.
3238 void ModuleBitcodeWriter::writeBlockInfo() {
3239   // We only want to emit block info records for blocks that have multiple
3240   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3241   // Other blocks can define their abbrevs inline.
3242   Stream.EnterBlockInfoBlock();
3243 
3244   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3245     auto Abbv = std::make_shared<BitCodeAbbrev>();
3246     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3247     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3248     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3249     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3250     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3251         VST_ENTRY_8_ABBREV)
3252       llvm_unreachable("Unexpected abbrev ordering!");
3253   }
3254 
3255   { // 7-bit fixed width VST_CODE_ENTRY strings.
3256     auto Abbv = std::make_shared<BitCodeAbbrev>();
3257     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3258     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3259     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3260     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3261     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3262         VST_ENTRY_7_ABBREV)
3263       llvm_unreachable("Unexpected abbrev ordering!");
3264   }
3265   { // 6-bit char6 VST_CODE_ENTRY strings.
3266     auto Abbv = std::make_shared<BitCodeAbbrev>();
3267     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3268     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3269     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3270     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3271     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3272         VST_ENTRY_6_ABBREV)
3273       llvm_unreachable("Unexpected abbrev ordering!");
3274   }
3275   { // 6-bit char6 VST_CODE_BBENTRY strings.
3276     auto Abbv = std::make_shared<BitCodeAbbrev>();
3277     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3278     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3279     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3280     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3281     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3282         VST_BBENTRY_6_ABBREV)
3283       llvm_unreachable("Unexpected abbrev ordering!");
3284   }
3285 
3286   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3287     auto Abbv = std::make_shared<BitCodeAbbrev>();
3288     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3289     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3290                               VE.computeBitsRequiredForTypeIndicies()));
3291     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3292         CONSTANTS_SETTYPE_ABBREV)
3293       llvm_unreachable("Unexpected abbrev ordering!");
3294   }
3295 
3296   { // INTEGER abbrev for CONSTANTS_BLOCK.
3297     auto Abbv = std::make_shared<BitCodeAbbrev>();
3298     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3299     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3300     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3301         CONSTANTS_INTEGER_ABBREV)
3302       llvm_unreachable("Unexpected abbrev ordering!");
3303   }
3304 
3305   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3306     auto Abbv = std::make_shared<BitCodeAbbrev>();
3307     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3308     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3309     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3310                               VE.computeBitsRequiredForTypeIndicies()));
3311     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3312 
3313     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3314         CONSTANTS_CE_CAST_Abbrev)
3315       llvm_unreachable("Unexpected abbrev ordering!");
3316   }
3317   { // NULL abbrev for CONSTANTS_BLOCK.
3318     auto Abbv = std::make_shared<BitCodeAbbrev>();
3319     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3320     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3321         CONSTANTS_NULL_Abbrev)
3322       llvm_unreachable("Unexpected abbrev ordering!");
3323   }
3324 
3325   // FIXME: This should only use space for first class types!
3326 
3327   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3328     auto Abbv = std::make_shared<BitCodeAbbrev>();
3329     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3330     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3331     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3332                               VE.computeBitsRequiredForTypeIndicies()));
3333     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3334     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3335     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3336         FUNCTION_INST_LOAD_ABBREV)
3337       llvm_unreachable("Unexpected abbrev ordering!");
3338   }
3339   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3340     auto Abbv = std::make_shared<BitCodeAbbrev>();
3341     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3342     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3343     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3344     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3345         FUNCTION_INST_UNOP_ABBREV)
3346       llvm_unreachable("Unexpected abbrev ordering!");
3347   }
3348   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3349     auto Abbv = std::make_shared<BitCodeAbbrev>();
3350     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3351     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3352     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3353     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3354     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3355         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3356       llvm_unreachable("Unexpected abbrev ordering!");
3357   }
3358   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3359     auto Abbv = std::make_shared<BitCodeAbbrev>();
3360     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3361     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3362     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3363     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3364     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3365         FUNCTION_INST_BINOP_ABBREV)
3366       llvm_unreachable("Unexpected abbrev ordering!");
3367   }
3368   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3369     auto Abbv = std::make_shared<BitCodeAbbrev>();
3370     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3371     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3372     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3373     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3374     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3375     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3376         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3377       llvm_unreachable("Unexpected abbrev ordering!");
3378   }
3379   { // INST_CAST abbrev for FUNCTION_BLOCK.
3380     auto Abbv = std::make_shared<BitCodeAbbrev>();
3381     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3382     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3383     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3384                               VE.computeBitsRequiredForTypeIndicies()));
3385     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3386     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3387         FUNCTION_INST_CAST_ABBREV)
3388       llvm_unreachable("Unexpected abbrev ordering!");
3389   }
3390 
3391   { // INST_RET abbrev for FUNCTION_BLOCK.
3392     auto Abbv = std::make_shared<BitCodeAbbrev>();
3393     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3394     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3395         FUNCTION_INST_RET_VOID_ABBREV)
3396       llvm_unreachable("Unexpected abbrev ordering!");
3397   }
3398   { // INST_RET abbrev for FUNCTION_BLOCK.
3399     auto Abbv = std::make_shared<BitCodeAbbrev>();
3400     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3401     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3402     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3403         FUNCTION_INST_RET_VAL_ABBREV)
3404       llvm_unreachable("Unexpected abbrev ordering!");
3405   }
3406   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3407     auto Abbv = std::make_shared<BitCodeAbbrev>();
3408     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3409     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3410         FUNCTION_INST_UNREACHABLE_ABBREV)
3411       llvm_unreachable("Unexpected abbrev ordering!");
3412   }
3413   {
3414     auto Abbv = std::make_shared<BitCodeAbbrev>();
3415     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3416     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3417     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3418                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3419     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3420     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3421     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3422         FUNCTION_INST_GEP_ABBREV)
3423       llvm_unreachable("Unexpected abbrev ordering!");
3424   }
3425 
3426   Stream.ExitBlock();
3427 }
3428 
3429 /// Write the module path strings, currently only used when generating
3430 /// a combined index file.
3431 void IndexBitcodeWriter::writeModStrings() {
3432   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3433 
3434   // TODO: See which abbrev sizes we actually need to emit
3435 
3436   // 8-bit fixed-width MST_ENTRY strings.
3437   auto Abbv = std::make_shared<BitCodeAbbrev>();
3438   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3439   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3440   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3441   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3442   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3443 
3444   // 7-bit fixed width MST_ENTRY strings.
3445   Abbv = std::make_shared<BitCodeAbbrev>();
3446   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3447   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3448   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3449   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3450   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3451 
3452   // 6-bit char6 MST_ENTRY strings.
3453   Abbv = std::make_shared<BitCodeAbbrev>();
3454   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3455   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3456   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3457   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3458   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3459 
3460   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3461   Abbv = std::make_shared<BitCodeAbbrev>();
3462   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3463   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3464   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3465   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3466   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3467   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3468   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3469 
3470   SmallVector<unsigned, 64> Vals;
3471   forEachModule(
3472       [&](const StringMapEntry<std::pair<uint64_t, ModuleHash>> &MPSE) {
3473         StringRef Key = MPSE.getKey();
3474         const auto &Value = MPSE.getValue();
3475         StringEncoding Bits = getStringEncoding(Key);
3476         unsigned AbbrevToUse = Abbrev8Bit;
3477         if (Bits == SE_Char6)
3478           AbbrevToUse = Abbrev6Bit;
3479         else if (Bits == SE_Fixed7)
3480           AbbrevToUse = Abbrev7Bit;
3481 
3482         Vals.push_back(Value.first);
3483         Vals.append(Key.begin(), Key.end());
3484 
3485         // Emit the finished record.
3486         Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3487 
3488         // Emit an optional hash for the module now
3489         const auto &Hash = Value.second;
3490         if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3491           Vals.assign(Hash.begin(), Hash.end());
3492           // Emit the hash record.
3493           Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3494         }
3495 
3496         Vals.clear();
3497       });
3498   Stream.ExitBlock();
3499 }
3500 
3501 /// Write the function type metadata related records that need to appear before
3502 /// a function summary entry (whether per-module or combined).
3503 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
3504                                              FunctionSummary *FS) {
3505   if (!FS->type_tests().empty())
3506     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3507 
3508   SmallVector<uint64_t, 64> Record;
3509 
3510   auto WriteVFuncIdVec = [&](uint64_t Ty,
3511                              ArrayRef<FunctionSummary::VFuncId> VFs) {
3512     if (VFs.empty())
3513       return;
3514     Record.clear();
3515     for (auto &VF : VFs) {
3516       Record.push_back(VF.GUID);
3517       Record.push_back(VF.Offset);
3518     }
3519     Stream.EmitRecord(Ty, Record);
3520   };
3521 
3522   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
3523                   FS->type_test_assume_vcalls());
3524   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
3525                   FS->type_checked_load_vcalls());
3526 
3527   auto WriteConstVCallVec = [&](uint64_t Ty,
3528                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
3529     for (auto &VC : VCs) {
3530       Record.clear();
3531       Record.push_back(VC.VFunc.GUID);
3532       Record.push_back(VC.VFunc.Offset);
3533       Record.insert(Record.end(), VC.Args.begin(), VC.Args.end());
3534       Stream.EmitRecord(Ty, Record);
3535     }
3536   };
3537 
3538   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
3539                      FS->type_test_assume_const_vcalls());
3540   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
3541                      FS->type_checked_load_const_vcalls());
3542 }
3543 
3544 /// Collect type IDs from type tests used by function.
3545 static void
3546 getReferencedTypeIds(FunctionSummary *FS,
3547                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
3548   if (!FS->type_tests().empty())
3549     for (auto &TT : FS->type_tests())
3550       ReferencedTypeIds.insert(TT);
3551 
3552   auto GetReferencedTypesFromVFuncIdVec =
3553       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
3554         for (auto &VF : VFs)
3555           ReferencedTypeIds.insert(VF.GUID);
3556       };
3557 
3558   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
3559   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
3560 
3561   auto GetReferencedTypesFromConstVCallVec =
3562       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
3563         for (auto &VC : VCs)
3564           ReferencedTypeIds.insert(VC.VFunc.GUID);
3565       };
3566 
3567   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
3568   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
3569 }
3570 
3571 static void writeWholeProgramDevirtResolutionByArg(
3572     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
3573     const WholeProgramDevirtResolution::ByArg &ByArg) {
3574   NameVals.push_back(args.size());
3575   NameVals.insert(NameVals.end(), args.begin(), args.end());
3576 
3577   NameVals.push_back(ByArg.TheKind);
3578   NameVals.push_back(ByArg.Info);
3579   NameVals.push_back(ByArg.Byte);
3580   NameVals.push_back(ByArg.Bit);
3581 }
3582 
3583 static void writeWholeProgramDevirtResolution(
3584     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3585     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
3586   NameVals.push_back(Id);
3587 
3588   NameVals.push_back(Wpd.TheKind);
3589   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
3590   NameVals.push_back(Wpd.SingleImplName.size());
3591 
3592   NameVals.push_back(Wpd.ResByArg.size());
3593   for (auto &A : Wpd.ResByArg)
3594     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
3595 }
3596 
3597 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
3598                                      StringTableBuilder &StrtabBuilder,
3599                                      const std::string &Id,
3600                                      const TypeIdSummary &Summary) {
3601   NameVals.push_back(StrtabBuilder.add(Id));
3602   NameVals.push_back(Id.size());
3603 
3604   NameVals.push_back(Summary.TTRes.TheKind);
3605   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
3606   NameVals.push_back(Summary.TTRes.AlignLog2);
3607   NameVals.push_back(Summary.TTRes.SizeM1);
3608   NameVals.push_back(Summary.TTRes.BitMask);
3609   NameVals.push_back(Summary.TTRes.InlineBits);
3610 
3611   for (auto &W : Summary.WPDRes)
3612     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
3613                                       W.second);
3614 }
3615 
3616 static void writeTypeIdCompatibleVtableSummaryRecord(
3617     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3618     const std::string &Id, const TypeIdCompatibleVtableInfo &Summary,
3619     ValueEnumerator &VE) {
3620   NameVals.push_back(StrtabBuilder.add(Id));
3621   NameVals.push_back(Id.size());
3622 
3623   for (auto &P : Summary) {
3624     NameVals.push_back(P.AddressPointOffset);
3625     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
3626   }
3627 }
3628 
3629 // Helper to emit a single function summary record.
3630 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
3631     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3632     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3633     const Function &F) {
3634   NameVals.push_back(ValueID);
3635 
3636   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3637   writeFunctionTypeMetadataRecords(Stream, FS);
3638 
3639   auto SpecialRefCnts = FS->specialRefCounts();
3640   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3641   NameVals.push_back(FS->instCount());
3642   NameVals.push_back(getEncodedFFlags(FS->fflags()));
3643   NameVals.push_back(FS->refs().size());
3644   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
3645   NameVals.push_back(SpecialRefCnts.second); // worefcnt
3646 
3647   for (auto &RI : FS->refs())
3648     NameVals.push_back(VE.getValueID(RI.getValue()));
3649 
3650   bool HasProfileData =
3651       F.hasProfileData() || ForceSummaryEdgesCold != FunctionSummary::FSHT_None;
3652   for (auto &ECI : FS->calls()) {
3653     NameVals.push_back(getValueId(ECI.first));
3654     if (HasProfileData)
3655       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
3656     else if (WriteRelBFToSummary)
3657       NameVals.push_back(ECI.second.RelBlockFreq);
3658   }
3659 
3660   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3661   unsigned Code =
3662       (HasProfileData ? bitc::FS_PERMODULE_PROFILE
3663                       : (WriteRelBFToSummary ? bitc::FS_PERMODULE_RELBF
3664                                              : bitc::FS_PERMODULE));
3665 
3666   // Emit the finished record.
3667   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3668   NameVals.clear();
3669 }
3670 
3671 // Collect the global value references in the given variable's initializer,
3672 // and emit them in a summary record.
3673 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
3674     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3675     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
3676   auto VI = Index->getValueInfo(V.getGUID());
3677   if (!VI || VI.getSummaryList().empty()) {
3678     // Only declarations should not have a summary (a declaration might however
3679     // have a summary if the def was in module level asm).
3680     assert(V.isDeclaration());
3681     return;
3682   }
3683   auto *Summary = VI.getSummaryList()[0].get();
3684   NameVals.push_back(VE.getValueID(&V));
3685   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
3686   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3687   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
3688 
3689   auto VTableFuncs = VS->vTableFuncs();
3690   if (!VTableFuncs.empty())
3691     NameVals.push_back(VS->refs().size());
3692 
3693   unsigned SizeBeforeRefs = NameVals.size();
3694   for (auto &RI : VS->refs())
3695     NameVals.push_back(VE.getValueID(RI.getValue()));
3696   // Sort the refs for determinism output, the vector returned by FS->refs() has
3697   // been initialized from a DenseSet.
3698   llvm::sort(NameVals.begin() + SizeBeforeRefs, NameVals.end());
3699 
3700   if (VTableFuncs.empty())
3701     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3702                       FSModRefsAbbrev);
3703   else {
3704     // VTableFuncs pairs should already be sorted by offset.
3705     for (auto &P : VTableFuncs) {
3706       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
3707       NameVals.push_back(P.VTableOffset);
3708     }
3709 
3710     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
3711                       FSModVTableRefsAbbrev);
3712   }
3713   NameVals.clear();
3714 }
3715 
3716 // Current version for the summary.
3717 // This is bumped whenever we introduce changes in the way some record are
3718 // interpreted, like flags for instance.
3719 static const uint64_t INDEX_VERSION = 7;
3720 
3721 /// Emit the per-module summary section alongside the rest of
3722 /// the module's bitcode.
3723 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
3724   // By default we compile with ThinLTO if the module has a summary, but the
3725   // client can request full LTO with a module flag.
3726   bool IsThinLTO = true;
3727   if (auto *MD =
3728           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
3729     IsThinLTO = MD->getZExtValue();
3730   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
3731                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
3732                        4);
3733 
3734   Stream.EmitRecord(bitc::FS_VERSION, ArrayRef<uint64_t>{INDEX_VERSION});
3735 
3736   // Write the index flags.
3737   uint64_t Flags = 0;
3738   // Bits 1-3 are set only in the combined index, skip them.
3739   if (Index->enableSplitLTOUnit())
3740     Flags |= 0x8;
3741   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
3742 
3743   if (Index->begin() == Index->end()) {
3744     Stream.ExitBlock();
3745     return;
3746   }
3747 
3748   for (const auto &GVI : valueIds()) {
3749     Stream.EmitRecord(bitc::FS_VALUE_GUID,
3750                       ArrayRef<uint64_t>{GVI.second, GVI.first});
3751   }
3752 
3753   // Abbrev for FS_PERMODULE_PROFILE.
3754   auto Abbv = std::make_shared<BitCodeAbbrev>();
3755   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
3756   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3757   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3758   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3759   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3760   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3761   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3762   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3763   // numrefs x valueid, n x (valueid, hotness)
3764   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3765   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3766   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3767 
3768   // Abbrev for FS_PERMODULE or FS_PERMODULE_RELBF.
3769   Abbv = std::make_shared<BitCodeAbbrev>();
3770   if (WriteRelBFToSummary)
3771     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
3772   else
3773     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
3774   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3775   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3776   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3777   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3778   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3779   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3780   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3781   // numrefs x valueid, n x (valueid [, rel_block_freq])
3782   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3783   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3784   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3785 
3786   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
3787   Abbv = std::make_shared<BitCodeAbbrev>();
3788   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
3789   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3790   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3791   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
3792   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3793   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3794 
3795   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
3796   Abbv = std::make_shared<BitCodeAbbrev>();
3797   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
3798   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3799   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3800   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
3801   // numrefs x valueid, n x (valueid , offset)
3802   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3803   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3804   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3805 
3806   // Abbrev for FS_ALIAS.
3807   Abbv = std::make_shared<BitCodeAbbrev>();
3808   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
3809   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3810   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3811   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3812   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3813 
3814   // Abbrev for FS_TYPE_ID_METADATA
3815   Abbv = std::make_shared<BitCodeAbbrev>();
3816   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
3817   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
3818   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
3819   // n x (valueid , offset)
3820   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3821   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3822   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3823 
3824   SmallVector<uint64_t, 64> NameVals;
3825   // Iterate over the list of functions instead of the Index to
3826   // ensure the ordering is stable.
3827   for (const Function &F : M) {
3828     // Summary emission does not support anonymous functions, they have to
3829     // renamed using the anonymous function renaming pass.
3830     if (!F.hasName())
3831       report_fatal_error("Unexpected anonymous function when writing summary");
3832 
3833     ValueInfo VI = Index->getValueInfo(F.getGUID());
3834     if (!VI || VI.getSummaryList().empty()) {
3835       // Only declarations should not have a summary (a declaration might
3836       // however have a summary if the def was in module level asm).
3837       assert(F.isDeclaration());
3838       continue;
3839     }
3840     auto *Summary = VI.getSummaryList()[0].get();
3841     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
3842                                         FSCallsAbbrev, FSCallsProfileAbbrev, F);
3843   }
3844 
3845   // Capture references from GlobalVariable initializers, which are outside
3846   // of a function scope.
3847   for (const GlobalVariable &G : M.globals())
3848     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
3849                                FSModVTableRefsAbbrev);
3850 
3851   for (const GlobalAlias &A : M.aliases()) {
3852     auto *Aliasee = A.getBaseObject();
3853     if (!Aliasee->hasName())
3854       // Nameless function don't have an entry in the summary, skip it.
3855       continue;
3856     auto AliasId = VE.getValueID(&A);
3857     auto AliaseeId = VE.getValueID(Aliasee);
3858     NameVals.push_back(AliasId);
3859     auto *Summary = Index->getGlobalValueSummary(A);
3860     AliasSummary *AS = cast<AliasSummary>(Summary);
3861     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
3862     NameVals.push_back(AliaseeId);
3863     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
3864     NameVals.clear();
3865   }
3866 
3867   for (auto &S : Index->typeIdCompatibleVtableMap()) {
3868     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
3869                                              S.second, VE);
3870     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
3871                       TypeIdCompatibleVtableAbbrev);
3872     NameVals.clear();
3873   }
3874 
3875   Stream.ExitBlock();
3876 }
3877 
3878 /// Emit the combined summary section into the combined index file.
3879 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
3880   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
3881   Stream.EmitRecord(bitc::FS_VERSION, ArrayRef<uint64_t>{INDEX_VERSION});
3882 
3883   // Write the index flags.
3884   uint64_t Flags = 0;
3885   if (Index.withGlobalValueDeadStripping())
3886     Flags |= 0x1;
3887   if (Index.skipModuleByDistributedBackend())
3888     Flags |= 0x2;
3889   if (Index.hasSyntheticEntryCounts())
3890     Flags |= 0x4;
3891   if (Index.enableSplitLTOUnit())
3892     Flags |= 0x8;
3893   if (Index.partiallySplitLTOUnits())
3894     Flags |= 0x10;
3895   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
3896 
3897   for (const auto &GVI : valueIds()) {
3898     Stream.EmitRecord(bitc::FS_VALUE_GUID,
3899                       ArrayRef<uint64_t>{GVI.second, GVI.first});
3900   }
3901 
3902   // Abbrev for FS_COMBINED.
3903   auto Abbv = std::make_shared<BitCodeAbbrev>();
3904   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
3905   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3906   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3907   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3908   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3909   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3910   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
3911   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3912   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3913   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3914   // numrefs x valueid, n x (valueid)
3915   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3916   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3917   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3918 
3919   // Abbrev for FS_COMBINED_PROFILE.
3920   Abbv = std::make_shared<BitCodeAbbrev>();
3921   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
3922   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3923   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3924   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3925   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3926   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3927   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
3928   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3929   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3930   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3931   // numrefs x valueid, n x (valueid, hotness)
3932   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3933   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3934   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3935 
3936   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
3937   Abbv = std::make_shared<BitCodeAbbrev>();
3938   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
3939   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3940   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3941   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3942   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
3943   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3944   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3945 
3946   // Abbrev for FS_COMBINED_ALIAS.
3947   Abbv = std::make_shared<BitCodeAbbrev>();
3948   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
3949   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3950   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3951   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3952   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3953   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3954 
3955   // The aliases are emitted as a post-pass, and will point to the value
3956   // id of the aliasee. Save them in a vector for post-processing.
3957   SmallVector<AliasSummary *, 64> Aliases;
3958 
3959   // Save the value id for each summary for alias emission.
3960   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
3961 
3962   SmallVector<uint64_t, 64> NameVals;
3963 
3964   // Set that will be populated during call to writeFunctionTypeMetadataRecords
3965   // with the type ids referenced by this index file.
3966   std::set<GlobalValue::GUID> ReferencedTypeIds;
3967 
3968   // For local linkage, we also emit the original name separately
3969   // immediately after the record.
3970   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
3971     if (!GlobalValue::isLocalLinkage(S.linkage()))
3972       return;
3973     NameVals.push_back(S.getOriginalName());
3974     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
3975     NameVals.clear();
3976   };
3977 
3978   std::set<GlobalValue::GUID> DefOrUseGUIDs;
3979   forEachSummary([&](GVInfo I, bool IsAliasee) {
3980     GlobalValueSummary *S = I.second;
3981     assert(S);
3982     DefOrUseGUIDs.insert(I.first);
3983     for (const ValueInfo &VI : S->refs())
3984       DefOrUseGUIDs.insert(VI.getGUID());
3985 
3986     auto ValueId = getValueId(I.first);
3987     assert(ValueId);
3988     SummaryToValueIdMap[S] = *ValueId;
3989 
3990     // If this is invoked for an aliasee, we want to record the above
3991     // mapping, but then not emit a summary entry (if the aliasee is
3992     // to be imported, we will invoke this separately with IsAliasee=false).
3993     if (IsAliasee)
3994       return;
3995 
3996     if (auto *AS = dyn_cast<AliasSummary>(S)) {
3997       // Will process aliases as a post-pass because the reader wants all
3998       // global to be loaded first.
3999       Aliases.push_back(AS);
4000       return;
4001     }
4002 
4003     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
4004       NameVals.push_back(*ValueId);
4005       NameVals.push_back(Index.getModuleId(VS->modulePath()));
4006       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4007       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4008       for (auto &RI : VS->refs()) {
4009         auto RefValueId = getValueId(RI.getGUID());
4010         if (!RefValueId)
4011           continue;
4012         NameVals.push_back(*RefValueId);
4013       }
4014 
4015       // Emit the finished record.
4016       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
4017                         FSModRefsAbbrev);
4018       NameVals.clear();
4019       MaybeEmitOriginalName(*S);
4020       return;
4021     }
4022 
4023     auto *FS = cast<FunctionSummary>(S);
4024     writeFunctionTypeMetadataRecords(Stream, FS);
4025     getReferencedTypeIds(FS, ReferencedTypeIds);
4026 
4027     NameVals.push_back(*ValueId);
4028     NameVals.push_back(Index.getModuleId(FS->modulePath()));
4029     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4030     NameVals.push_back(FS->instCount());
4031     NameVals.push_back(getEncodedFFlags(FS->fflags()));
4032     NameVals.push_back(FS->entryCount());
4033 
4034     // Fill in below
4035     NameVals.push_back(0); // numrefs
4036     NameVals.push_back(0); // rorefcnt
4037     NameVals.push_back(0); // worefcnt
4038 
4039     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
4040     for (auto &RI : FS->refs()) {
4041       auto RefValueId = getValueId(RI.getGUID());
4042       if (!RefValueId)
4043         continue;
4044       NameVals.push_back(*RefValueId);
4045       if (RI.isReadOnly())
4046         RORefCnt++;
4047       else if (RI.isWriteOnly())
4048         WORefCnt++;
4049       Count++;
4050     }
4051     NameVals[6] = Count;
4052     NameVals[7] = RORefCnt;
4053     NameVals[8] = WORefCnt;
4054 
4055     bool HasProfileData = false;
4056     for (auto &EI : FS->calls()) {
4057       HasProfileData |=
4058           EI.second.getHotness() != CalleeInfo::HotnessType::Unknown;
4059       if (HasProfileData)
4060         break;
4061     }
4062 
4063     for (auto &EI : FS->calls()) {
4064       // If this GUID doesn't have a value id, it doesn't have a function
4065       // summary and we don't need to record any calls to it.
4066       GlobalValue::GUID GUID = EI.first.getGUID();
4067       auto CallValueId = getValueId(GUID);
4068       if (!CallValueId) {
4069         // For SamplePGO, the indirect call targets for local functions will
4070         // have its original name annotated in profile. We try to find the
4071         // corresponding PGOFuncName as the GUID.
4072         GUID = Index.getGUIDFromOriginalID(GUID);
4073         if (GUID == 0)
4074           continue;
4075         CallValueId = getValueId(GUID);
4076         if (!CallValueId)
4077           continue;
4078         // The mapping from OriginalId to GUID may return a GUID
4079         // that corresponds to a static variable. Filter it out here.
4080         // This can happen when
4081         // 1) There is a call to a library function which does not have
4082         // a CallValidId;
4083         // 2) There is a static variable with the  OriginalGUID identical
4084         // to the GUID of the library function in 1);
4085         // When this happens, the logic for SamplePGO kicks in and
4086         // the static variable in 2) will be found, which needs to be
4087         // filtered out.
4088         auto *GVSum = Index.getGlobalValueSummary(GUID, false);
4089         if (GVSum &&
4090             GVSum->getSummaryKind() == GlobalValueSummary::GlobalVarKind)
4091           continue;
4092       }
4093       NameVals.push_back(*CallValueId);
4094       if (HasProfileData)
4095         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
4096     }
4097 
4098     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
4099     unsigned Code =
4100         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
4101 
4102     // Emit the finished record.
4103     Stream.EmitRecord(Code, NameVals, FSAbbrev);
4104     NameVals.clear();
4105     MaybeEmitOriginalName(*S);
4106   });
4107 
4108   for (auto *AS : Aliases) {
4109     auto AliasValueId = SummaryToValueIdMap[AS];
4110     assert(AliasValueId);
4111     NameVals.push_back(AliasValueId);
4112     NameVals.push_back(Index.getModuleId(AS->modulePath()));
4113     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4114     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4115     assert(AliaseeValueId);
4116     NameVals.push_back(AliaseeValueId);
4117 
4118     // Emit the finished record.
4119     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4120     NameVals.clear();
4121     MaybeEmitOriginalName(*AS);
4122 
4123     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4124       getReferencedTypeIds(FS, ReferencedTypeIds);
4125   }
4126 
4127   if (!Index.cfiFunctionDefs().empty()) {
4128     for (auto &S : Index.cfiFunctionDefs()) {
4129       if (DefOrUseGUIDs.count(
4130               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4131         NameVals.push_back(StrtabBuilder.add(S));
4132         NameVals.push_back(S.size());
4133       }
4134     }
4135     if (!NameVals.empty()) {
4136       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4137       NameVals.clear();
4138     }
4139   }
4140 
4141   if (!Index.cfiFunctionDecls().empty()) {
4142     for (auto &S : Index.cfiFunctionDecls()) {
4143       if (DefOrUseGUIDs.count(
4144               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4145         NameVals.push_back(StrtabBuilder.add(S));
4146         NameVals.push_back(S.size());
4147       }
4148     }
4149     if (!NameVals.empty()) {
4150       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4151       NameVals.clear();
4152     }
4153   }
4154 
4155   // Walk the GUIDs that were referenced, and write the
4156   // corresponding type id records.
4157   for (auto &T : ReferencedTypeIds) {
4158     auto TidIter = Index.typeIds().equal_range(T);
4159     for (auto It = TidIter.first; It != TidIter.second; ++It) {
4160       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, It->second.first,
4161                                It->second.second);
4162       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4163       NameVals.clear();
4164     }
4165   }
4166 
4167   Stream.ExitBlock();
4168 }
4169 
4170 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4171 /// current llvm version, and a record for the epoch number.
4172 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4173   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4174 
4175   // Write the "user readable" string identifying the bitcode producer
4176   auto Abbv = std::make_shared<BitCodeAbbrev>();
4177   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4178   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4179   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4180   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4181   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4182                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4183 
4184   // Write the epoch version
4185   Abbv = std::make_shared<BitCodeAbbrev>();
4186   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4187   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4188   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4189   SmallVector<unsigned, 1> Vals = {bitc::BITCODE_CURRENT_EPOCH};
4190   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4191   Stream.ExitBlock();
4192 }
4193 
4194 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
4195   // Emit the module's hash.
4196   // MODULE_CODE_HASH: [5*i32]
4197   if (GenerateHash) {
4198     uint32_t Vals[5];
4199     Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
4200                                     Buffer.size() - BlockStartPos));
4201     StringRef Hash = Hasher.result();
4202     for (int Pos = 0; Pos < 20; Pos += 4) {
4203       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4204     }
4205 
4206     // Emit the finished record.
4207     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4208 
4209     if (ModHash)
4210       // Save the written hash value.
4211       llvm::copy(Vals, std::begin(*ModHash));
4212   }
4213 }
4214 
4215 void ModuleBitcodeWriter::write() {
4216   writeIdentificationBlock(Stream);
4217 
4218   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4219   size_t BlockStartPos = Buffer.size();
4220 
4221   writeModuleVersion();
4222 
4223   // Emit blockinfo, which defines the standard abbreviations etc.
4224   writeBlockInfo();
4225 
4226   // Emit information describing all of the types in the module.
4227   writeTypeTable();
4228 
4229   // Emit information about attribute groups.
4230   writeAttributeGroupTable();
4231 
4232   // Emit information about parameter attributes.
4233   writeAttributeTable();
4234 
4235   writeComdats();
4236 
4237   // Emit top-level description of module, including target triple, inline asm,
4238   // descriptors for global variables, and function prototype info.
4239   writeModuleInfo();
4240 
4241   // Emit constants.
4242   writeModuleConstants();
4243 
4244   // Emit metadata kind names.
4245   writeModuleMetadataKinds();
4246 
4247   // Emit metadata.
4248   writeModuleMetadata();
4249 
4250   // Emit module-level use-lists.
4251   if (VE.shouldPreserveUseListOrder())
4252     writeUseListBlock(nullptr);
4253 
4254   writeOperandBundleTags();
4255   writeSyncScopeNames();
4256 
4257   // Emit function bodies.
4258   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4259   for (Module::const_iterator F = M.begin(), E = M.end(); F != E; ++F)
4260     if (!F->isDeclaration())
4261       writeFunction(*F, FunctionToBitcodeIndex);
4262 
4263   // Need to write after the above call to WriteFunction which populates
4264   // the summary information in the index.
4265   if (Index)
4266     writePerModuleGlobalValueSummary();
4267 
4268   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4269 
4270   writeModuleHash(BlockStartPos);
4271 
4272   Stream.ExitBlock();
4273 }
4274 
4275 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4276                                uint32_t &Position) {
4277   support::endian::write32le(&Buffer[Position], Value);
4278   Position += 4;
4279 }
4280 
4281 /// If generating a bc file on darwin, we have to emit a
4282 /// header and trailer to make it compatible with the system archiver.  To do
4283 /// this we emit the following header, and then emit a trailer that pads the
4284 /// file out to be a multiple of 16 bytes.
4285 ///
4286 /// struct bc_header {
4287 ///   uint32_t Magic;         // 0x0B17C0DE
4288 ///   uint32_t Version;       // Version, currently always 0.
4289 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4290 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4291 ///   uint32_t CPUType;       // CPU specifier.
4292 ///   ... potentially more later ...
4293 /// };
4294 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4295                                          const Triple &TT) {
4296   unsigned CPUType = ~0U;
4297 
4298   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4299   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4300   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4301   // specific constants here because they are implicitly part of the Darwin ABI.
4302   enum {
4303     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4304     DARWIN_CPU_TYPE_X86        = 7,
4305     DARWIN_CPU_TYPE_ARM        = 12,
4306     DARWIN_CPU_TYPE_POWERPC    = 18
4307   };
4308 
4309   Triple::ArchType Arch = TT.getArch();
4310   if (Arch == Triple::x86_64)
4311     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4312   else if (Arch == Triple::x86)
4313     CPUType = DARWIN_CPU_TYPE_X86;
4314   else if (Arch == Triple::ppc)
4315     CPUType = DARWIN_CPU_TYPE_POWERPC;
4316   else if (Arch == Triple::ppc64)
4317     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
4318   else if (Arch == Triple::arm || Arch == Triple::thumb)
4319     CPUType = DARWIN_CPU_TYPE_ARM;
4320 
4321   // Traditional Bitcode starts after header.
4322   assert(Buffer.size() >= BWH_HeaderSize &&
4323          "Expected header size to be reserved");
4324   unsigned BCOffset = BWH_HeaderSize;
4325   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
4326 
4327   // Write the magic and version.
4328   unsigned Position = 0;
4329   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
4330   writeInt32ToBuffer(0, Buffer, Position); // Version.
4331   writeInt32ToBuffer(BCOffset, Buffer, Position);
4332   writeInt32ToBuffer(BCSize, Buffer, Position);
4333   writeInt32ToBuffer(CPUType, Buffer, Position);
4334 
4335   // If the file is not a multiple of 16 bytes, insert dummy padding.
4336   while (Buffer.size() & 15)
4337     Buffer.push_back(0);
4338 }
4339 
4340 /// Helper to write the header common to all bitcode files.
4341 static void writeBitcodeHeader(BitstreamWriter &Stream) {
4342   // Emit the file header.
4343   Stream.Emit((unsigned)'B', 8);
4344   Stream.Emit((unsigned)'C', 8);
4345   Stream.Emit(0x0, 4);
4346   Stream.Emit(0xC, 4);
4347   Stream.Emit(0xE, 4);
4348   Stream.Emit(0xD, 4);
4349 }
4350 
4351 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer)
4352     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer)) {
4353   writeBitcodeHeader(*Stream);
4354 }
4355 
4356 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
4357 
4358 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
4359   Stream->EnterSubblock(Block, 3);
4360 
4361   auto Abbv = std::make_shared<BitCodeAbbrev>();
4362   Abbv->Add(BitCodeAbbrevOp(Record));
4363   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
4364   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
4365 
4366   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
4367 
4368   Stream->ExitBlock();
4369 }
4370 
4371 void BitcodeWriter::writeSymtab() {
4372   assert(!WroteStrtab && !WroteSymtab);
4373 
4374   // If any module has module-level inline asm, we will require a registered asm
4375   // parser for the target so that we can create an accurate symbol table for
4376   // the module.
4377   for (Module *M : Mods) {
4378     if (M->getModuleInlineAsm().empty())
4379       continue;
4380 
4381     std::string Err;
4382     const Triple TT(M->getTargetTriple());
4383     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
4384     if (!T || !T->hasMCAsmParser())
4385       return;
4386   }
4387 
4388   WroteSymtab = true;
4389   SmallVector<char, 0> Symtab;
4390   // The irsymtab::build function may be unable to create a symbol table if the
4391   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
4392   // table is not required for correctness, but we still want to be able to
4393   // write malformed modules to bitcode files, so swallow the error.
4394   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
4395     consumeError(std::move(E));
4396     return;
4397   }
4398 
4399   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
4400             {Symtab.data(), Symtab.size()});
4401 }
4402 
4403 void BitcodeWriter::writeStrtab() {
4404   assert(!WroteStrtab);
4405 
4406   std::vector<char> Strtab;
4407   StrtabBuilder.finalizeInOrder();
4408   Strtab.resize(StrtabBuilder.getSize());
4409   StrtabBuilder.write((uint8_t *)Strtab.data());
4410 
4411   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
4412             {Strtab.data(), Strtab.size()});
4413 
4414   WroteStrtab = true;
4415 }
4416 
4417 void BitcodeWriter::copyStrtab(StringRef Strtab) {
4418   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
4419   WroteStrtab = true;
4420 }
4421 
4422 void BitcodeWriter::writeModule(const Module &M,
4423                                 bool ShouldPreserveUseListOrder,
4424                                 const ModuleSummaryIndex *Index,
4425                                 bool GenerateHash, ModuleHash *ModHash) {
4426   assert(!WroteStrtab);
4427 
4428   // The Mods vector is used by irsymtab::build, which requires non-const
4429   // Modules in case it needs to materialize metadata. But the bitcode writer
4430   // requires that the module is materialized, so we can cast to non-const here,
4431   // after checking that it is in fact materialized.
4432   assert(M.isMaterialized());
4433   Mods.push_back(const_cast<Module *>(&M));
4434 
4435   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
4436                                    ShouldPreserveUseListOrder, Index,
4437                                    GenerateHash, ModHash);
4438   ModuleWriter.write();
4439 }
4440 
4441 void BitcodeWriter::writeIndex(
4442     const ModuleSummaryIndex *Index,
4443     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4444   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
4445                                  ModuleToSummariesForIndex);
4446   IndexWriter.write();
4447 }
4448 
4449 /// Write the specified module to the specified output stream.
4450 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
4451                               bool ShouldPreserveUseListOrder,
4452                               const ModuleSummaryIndex *Index,
4453                               bool GenerateHash, ModuleHash *ModHash) {
4454   SmallVector<char, 0> Buffer;
4455   Buffer.reserve(256*1024);
4456 
4457   // If this is darwin or another generic macho target, reserve space for the
4458   // header.
4459   Triple TT(M.getTargetTriple());
4460   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4461     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
4462 
4463   BitcodeWriter Writer(Buffer);
4464   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
4465                      ModHash);
4466   Writer.writeSymtab();
4467   Writer.writeStrtab();
4468 
4469   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4470     emitDarwinBCHeaderAndTrailer(Buffer, TT);
4471 
4472   // Write the generated bitstream to "Out".
4473   Out.write((char*)&Buffer.front(), Buffer.size());
4474 }
4475 
4476 void IndexBitcodeWriter::write() {
4477   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4478 
4479   writeModuleVersion();
4480 
4481   // Write the module paths in the combined index.
4482   writeModStrings();
4483 
4484   // Write the summary combined index records.
4485   writeCombinedGlobalValueSummary();
4486 
4487   Stream.ExitBlock();
4488 }
4489 
4490 // Write the specified module summary index to the given raw output stream,
4491 // where it will be written in a new bitcode block. This is used when
4492 // writing the combined index file for ThinLTO. When writing a subset of the
4493 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
4494 void llvm::WriteIndexToFile(
4495     const ModuleSummaryIndex &Index, raw_ostream &Out,
4496     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4497   SmallVector<char, 0> Buffer;
4498   Buffer.reserve(256 * 1024);
4499 
4500   BitcodeWriter Writer(Buffer);
4501   Writer.writeIndex(&Index, ModuleToSummariesForIndex);
4502   Writer.writeStrtab();
4503 
4504   Out.write((char *)&Buffer.front(), Buffer.size());
4505 }
4506 
4507 namespace {
4508 
4509 /// Class to manage the bitcode writing for a thin link bitcode file.
4510 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
4511   /// ModHash is for use in ThinLTO incremental build, generated while writing
4512   /// the module bitcode file.
4513   const ModuleHash *ModHash;
4514 
4515 public:
4516   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
4517                         BitstreamWriter &Stream,
4518                         const ModuleSummaryIndex &Index,
4519                         const ModuleHash &ModHash)
4520       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
4521                                 /*ShouldPreserveUseListOrder=*/false, &Index),
4522         ModHash(&ModHash) {}
4523 
4524   void write();
4525 
4526 private:
4527   void writeSimplifiedModuleInfo();
4528 };
4529 
4530 } // end anonymous namespace
4531 
4532 // This function writes a simpilified module info for thin link bitcode file.
4533 // It only contains the source file name along with the name(the offset and
4534 // size in strtab) and linkage for global values. For the global value info
4535 // entry, in order to keep linkage at offset 5, there are three zeros used
4536 // as padding.
4537 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
4538   SmallVector<unsigned, 64> Vals;
4539   // Emit the module's source file name.
4540   {
4541     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
4542     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
4543     if (Bits == SE_Char6)
4544       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
4545     else if (Bits == SE_Fixed7)
4546       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
4547 
4548     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
4549     auto Abbv = std::make_shared<BitCodeAbbrev>();
4550     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
4551     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4552     Abbv->Add(AbbrevOpToUse);
4553     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4554 
4555     for (const auto P : M.getSourceFileName())
4556       Vals.push_back((unsigned char)P);
4557 
4558     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
4559     Vals.clear();
4560   }
4561 
4562   // Emit the global variable information.
4563   for (const GlobalVariable &GV : M.globals()) {
4564     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
4565     Vals.push_back(StrtabBuilder.add(GV.getName()));
4566     Vals.push_back(GV.getName().size());
4567     Vals.push_back(0);
4568     Vals.push_back(0);
4569     Vals.push_back(0);
4570     Vals.push_back(getEncodedLinkage(GV));
4571 
4572     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
4573     Vals.clear();
4574   }
4575 
4576   // Emit the function proto information.
4577   for (const Function &F : M) {
4578     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
4579     Vals.push_back(StrtabBuilder.add(F.getName()));
4580     Vals.push_back(F.getName().size());
4581     Vals.push_back(0);
4582     Vals.push_back(0);
4583     Vals.push_back(0);
4584     Vals.push_back(getEncodedLinkage(F));
4585 
4586     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
4587     Vals.clear();
4588   }
4589 
4590   // Emit the alias information.
4591   for (const GlobalAlias &A : M.aliases()) {
4592     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
4593     Vals.push_back(StrtabBuilder.add(A.getName()));
4594     Vals.push_back(A.getName().size());
4595     Vals.push_back(0);
4596     Vals.push_back(0);
4597     Vals.push_back(0);
4598     Vals.push_back(getEncodedLinkage(A));
4599 
4600     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
4601     Vals.clear();
4602   }
4603 
4604   // Emit the ifunc information.
4605   for (const GlobalIFunc &I : M.ifuncs()) {
4606     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
4607     Vals.push_back(StrtabBuilder.add(I.getName()));
4608     Vals.push_back(I.getName().size());
4609     Vals.push_back(0);
4610     Vals.push_back(0);
4611     Vals.push_back(0);
4612     Vals.push_back(getEncodedLinkage(I));
4613 
4614     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
4615     Vals.clear();
4616   }
4617 }
4618 
4619 void ThinLinkBitcodeWriter::write() {
4620   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4621 
4622   writeModuleVersion();
4623 
4624   writeSimplifiedModuleInfo();
4625 
4626   writePerModuleGlobalValueSummary();
4627 
4628   // Write module hash.
4629   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
4630 
4631   Stream.ExitBlock();
4632 }
4633 
4634 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
4635                                          const ModuleSummaryIndex &Index,
4636                                          const ModuleHash &ModHash) {
4637   assert(!WroteStrtab);
4638 
4639   // The Mods vector is used by irsymtab::build, which requires non-const
4640   // Modules in case it needs to materialize metadata. But the bitcode writer
4641   // requires that the module is materialized, so we can cast to non-const here,
4642   // after checking that it is in fact materialized.
4643   assert(M.isMaterialized());
4644   Mods.push_back(const_cast<Module *>(&M));
4645 
4646   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
4647                                        ModHash);
4648   ThinLinkWriter.write();
4649 }
4650 
4651 // Write the specified thin link bitcode file to the given raw output stream,
4652 // where it will be written in a new bitcode block. This is used when
4653 // writing the per-module index file for ThinLTO.
4654 void llvm::WriteThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
4655                                       const ModuleSummaryIndex &Index,
4656                                       const ModuleHash &ModHash) {
4657   SmallVector<char, 0> Buffer;
4658   Buffer.reserve(256 * 1024);
4659 
4660   BitcodeWriter Writer(Buffer);
4661   Writer.writeThinLinkBitcode(M, Index, ModHash);
4662   Writer.writeSymtab();
4663   Writer.writeStrtab();
4664 
4665   Out.write((char *)&Buffer.front(), Buffer.size());
4666 }
4667