xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision 3b77583e95236761d8741fd6df375975a8ca5d83)
1 //===- Bitcode/Writer/BitcodeWriter.cpp - Bitcode Writer ------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // Bitcode writer implementation.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "llvm/Bitcode/BitcodeWriter.h"
14 #include "ValueEnumerator.h"
15 #include "llvm/ADT/APFloat.h"
16 #include "llvm/ADT/APInt.h"
17 #include "llvm/ADT/ArrayRef.h"
18 #include "llvm/ADT/DenseMap.h"
19 #include "llvm/ADT/None.h"
20 #include "llvm/ADT/Optional.h"
21 #include "llvm/ADT/STLExtras.h"
22 #include "llvm/ADT/SmallString.h"
23 #include "llvm/ADT/SmallVector.h"
24 #include "llvm/ADT/StringMap.h"
25 #include "llvm/ADT/StringRef.h"
26 #include "llvm/ADT/Triple.h"
27 #include "llvm/Bitcode/BitCodes.h"
28 #include "llvm/Bitcode/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 
219   void assignValueId(GlobalValue::GUID ValGUID) {
220     GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
221   }
222 
223   unsigned getValueId(GlobalValue::GUID ValGUID) {
224     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
225     // Expect that any GUID value had a value Id assigned by an
226     // earlier call to assignValueId.
227     assert(VMI != GUIDToValueIdMap.end() &&
228            "GUID does not have assigned value Id");
229     return VMI->second;
230   }
231 
232   // Helper to get the valueId for the type of value recorded in VI.
233   unsigned getValueId(ValueInfo VI) {
234     if (!VI.haveGVs() || !VI.getValue())
235       return getValueId(VI.getGUID());
236     return VE.getValueID(VI.getValue());
237   }
238 
239   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
240 };
241 
242 /// Class to manage the bitcode writing for a module.
243 class ModuleBitcodeWriter : public ModuleBitcodeWriterBase {
244   /// Pointer to the buffer allocated by caller for bitcode writing.
245   const SmallVectorImpl<char> &Buffer;
246 
247   /// True if a module hash record should be written.
248   bool GenerateHash;
249 
250   /// If non-null, when GenerateHash is true, the resulting hash is written
251   /// into ModHash.
252   ModuleHash *ModHash;
253 
254   SHA1 Hasher;
255 
256   /// The start bit of the identification block.
257   uint64_t BitcodeStartBit;
258 
259 public:
260   /// Constructs a ModuleBitcodeWriter object for the given Module,
261   /// writing to the provided \p Buffer.
262   ModuleBitcodeWriter(const Module &M, SmallVectorImpl<char> &Buffer,
263                       StringTableBuilder &StrtabBuilder,
264                       BitstreamWriter &Stream, bool ShouldPreserveUseListOrder,
265                       const ModuleSummaryIndex *Index, bool GenerateHash,
266                       ModuleHash *ModHash = nullptr)
267       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
268                                 ShouldPreserveUseListOrder, Index),
269         Buffer(Buffer), GenerateHash(GenerateHash), ModHash(ModHash),
270         BitcodeStartBit(Stream.GetCurrentBitNo()) {}
271 
272   /// Emit the current module to the bitstream.
273   void write();
274 
275 private:
276   uint64_t bitcodeStartBit() { return BitcodeStartBit; }
277 
278   size_t addToStrtab(StringRef Str);
279 
280   void writeAttributeGroupTable();
281   void writeAttributeTable();
282   void writeTypeTable();
283   void writeComdats();
284   void writeValueSymbolTableForwardDecl();
285   void writeModuleInfo();
286   void writeValueAsMetadata(const ValueAsMetadata *MD,
287                             SmallVectorImpl<uint64_t> &Record);
288   void writeMDTuple(const MDTuple *N, SmallVectorImpl<uint64_t> &Record,
289                     unsigned Abbrev);
290   unsigned createDILocationAbbrev();
291   void writeDILocation(const DILocation *N, SmallVectorImpl<uint64_t> &Record,
292                        unsigned &Abbrev);
293   unsigned createGenericDINodeAbbrev();
294   void writeGenericDINode(const GenericDINode *N,
295                           SmallVectorImpl<uint64_t> &Record, unsigned &Abbrev);
296   void writeDISubrange(const DISubrange *N, SmallVectorImpl<uint64_t> &Record,
297                        unsigned Abbrev);
298   void writeDIEnumerator(const DIEnumerator *N,
299                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
300   void writeDIBasicType(const DIBasicType *N, SmallVectorImpl<uint64_t> &Record,
301                         unsigned Abbrev);
302   void writeDIDerivedType(const DIDerivedType *N,
303                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
304   void writeDICompositeType(const DICompositeType *N,
305                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
306   void writeDISubroutineType(const DISubroutineType *N,
307                              SmallVectorImpl<uint64_t> &Record,
308                              unsigned Abbrev);
309   void writeDIFile(const DIFile *N, SmallVectorImpl<uint64_t> &Record,
310                    unsigned Abbrev);
311   void writeDICompileUnit(const DICompileUnit *N,
312                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
313   void writeDISubprogram(const DISubprogram *N,
314                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
315   void writeDILexicalBlock(const DILexicalBlock *N,
316                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
317   void writeDILexicalBlockFile(const DILexicalBlockFile *N,
318                                SmallVectorImpl<uint64_t> &Record,
319                                unsigned Abbrev);
320   void writeDICommonBlock(const DICommonBlock *N,
321                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
322   void writeDINamespace(const DINamespace *N, SmallVectorImpl<uint64_t> &Record,
323                         unsigned Abbrev);
324   void writeDIMacro(const DIMacro *N, SmallVectorImpl<uint64_t> &Record,
325                     unsigned Abbrev);
326   void writeDIMacroFile(const DIMacroFile *N, SmallVectorImpl<uint64_t> &Record,
327                         unsigned Abbrev);
328   void writeDIModule(const DIModule *N, SmallVectorImpl<uint64_t> &Record,
329                      unsigned Abbrev);
330   void writeDITemplateTypeParameter(const DITemplateTypeParameter *N,
331                                     SmallVectorImpl<uint64_t> &Record,
332                                     unsigned Abbrev);
333   void writeDITemplateValueParameter(const DITemplateValueParameter *N,
334                                      SmallVectorImpl<uint64_t> &Record,
335                                      unsigned Abbrev);
336   void writeDIGlobalVariable(const DIGlobalVariable *N,
337                              SmallVectorImpl<uint64_t> &Record,
338                              unsigned Abbrev);
339   void writeDILocalVariable(const DILocalVariable *N,
340                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
341   void writeDILabel(const DILabel *N,
342                     SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
343   void writeDIExpression(const DIExpression *N,
344                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
345   void writeDIGlobalVariableExpression(const DIGlobalVariableExpression *N,
346                                        SmallVectorImpl<uint64_t> &Record,
347                                        unsigned Abbrev);
348   void writeDIObjCProperty(const DIObjCProperty *N,
349                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
350   void writeDIImportedEntity(const DIImportedEntity *N,
351                              SmallVectorImpl<uint64_t> &Record,
352                              unsigned Abbrev);
353   unsigned createNamedMetadataAbbrev();
354   void writeNamedMetadata(SmallVectorImpl<uint64_t> &Record);
355   unsigned createMetadataStringsAbbrev();
356   void writeMetadataStrings(ArrayRef<const Metadata *> Strings,
357                             SmallVectorImpl<uint64_t> &Record);
358   void writeMetadataRecords(ArrayRef<const Metadata *> MDs,
359                             SmallVectorImpl<uint64_t> &Record,
360                             std::vector<unsigned> *MDAbbrevs = nullptr,
361                             std::vector<uint64_t> *IndexPos = nullptr);
362   void writeModuleMetadata();
363   void writeFunctionMetadata(const Function &F);
364   void writeFunctionMetadataAttachment(const Function &F);
365   void writeGlobalVariableMetadataAttachment(const GlobalVariable &GV);
366   void pushGlobalMetadataAttachment(SmallVectorImpl<uint64_t> &Record,
367                                     const GlobalObject &GO);
368   void writeModuleMetadataKinds();
369   void writeOperandBundleTags();
370   void writeSyncScopeNames();
371   void writeConstants(unsigned FirstVal, unsigned LastVal, bool isGlobal);
372   void writeModuleConstants();
373   bool pushValueAndType(const Value *V, unsigned InstID,
374                         SmallVectorImpl<unsigned> &Vals);
375   void writeOperandBundles(ImmutableCallSite CS, unsigned InstID);
376   void pushValue(const Value *V, unsigned InstID,
377                  SmallVectorImpl<unsigned> &Vals);
378   void pushValueSigned(const Value *V, unsigned InstID,
379                        SmallVectorImpl<uint64_t> &Vals);
380   void writeInstruction(const Instruction &I, unsigned InstID,
381                         SmallVectorImpl<unsigned> &Vals);
382   void writeFunctionLevelValueSymbolTable(const ValueSymbolTable &VST);
383   void writeGlobalValueSymbolTable(
384       DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
385   void writeUseList(UseListOrder &&Order);
386   void writeUseListBlock(const Function *F);
387   void
388   writeFunction(const Function &F,
389                 DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
390   void writeBlockInfo();
391   void writeModuleHash(size_t BlockStartPos);
392 
393   unsigned getEncodedSyncScopeID(SyncScope::ID SSID) {
394     return unsigned(SSID);
395   }
396 };
397 
398 /// Class to manage the bitcode writing for a combined index.
399 class IndexBitcodeWriter : public BitcodeWriterBase {
400   /// The combined index to write to bitcode.
401   const ModuleSummaryIndex &Index;
402 
403   /// When writing a subset of the index for distributed backends, client
404   /// provides a map of modules to the corresponding GUIDs/summaries to write.
405   const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex;
406 
407   /// Map that holds the correspondence between the GUID used in the combined
408   /// index and a value id generated by this class to use in references.
409   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
410 
411   /// Tracks the last value id recorded in the GUIDToValueMap.
412   unsigned GlobalValueId = 0;
413 
414 public:
415   /// Constructs a IndexBitcodeWriter object for the given combined index,
416   /// writing to the provided \p Buffer. When writing a subset of the index
417   /// for a distributed backend, provide a \p ModuleToSummariesForIndex map.
418   IndexBitcodeWriter(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder,
419                      const ModuleSummaryIndex &Index,
420                      const std::map<std::string, GVSummaryMapTy>
421                          *ModuleToSummariesForIndex = nullptr)
422       : BitcodeWriterBase(Stream, StrtabBuilder), Index(Index),
423         ModuleToSummariesForIndex(ModuleToSummariesForIndex) {
424     // Assign unique value ids to all summaries to be written, for use
425     // in writing out the call graph edges. Save the mapping from GUID
426     // to the new global value id to use when writing those edges, which
427     // are currently saved in the index in terms of GUID.
428     forEachSummary([&](GVInfo I, bool) {
429       GUIDToValueIdMap[I.first] = ++GlobalValueId;
430     });
431   }
432 
433   /// The below iterator returns the GUID and associated summary.
434   using GVInfo = std::pair<GlobalValue::GUID, GlobalValueSummary *>;
435 
436   /// Calls the callback for each value GUID and summary to be written to
437   /// bitcode. This hides the details of whether they are being pulled from the
438   /// entire index or just those in a provided ModuleToSummariesForIndex map.
439   template<typename Functor>
440   void forEachSummary(Functor Callback) {
441     if (ModuleToSummariesForIndex) {
442       for (auto &M : *ModuleToSummariesForIndex)
443         for (auto &Summary : M.second) {
444           Callback(Summary, false);
445           // Ensure aliasee is handled, e.g. for assigning a valueId,
446           // even if we are not importing the aliasee directly (the
447           // imported alias will contain a copy of aliasee).
448           if (auto *AS = dyn_cast<AliasSummary>(Summary.getSecond()))
449             Callback({AS->getAliaseeGUID(), &AS->getAliasee()}, true);
450         }
451     } else {
452       for (auto &Summaries : Index)
453         for (auto &Summary : Summaries.second.SummaryList)
454           Callback({Summaries.first, Summary.get()}, false);
455     }
456   }
457 
458   /// Calls the callback for each entry in the modulePaths StringMap that
459   /// should be written to the module path string table. This hides the details
460   /// of whether they are being pulled from the entire index or just those in a
461   /// provided ModuleToSummariesForIndex map.
462   template <typename Functor> void forEachModule(Functor Callback) {
463     if (ModuleToSummariesForIndex) {
464       for (const auto &M : *ModuleToSummariesForIndex) {
465         const auto &MPI = Index.modulePaths().find(M.first);
466         if (MPI == Index.modulePaths().end()) {
467           // This should only happen if the bitcode file was empty, in which
468           // case we shouldn't be importing (the ModuleToSummariesForIndex
469           // would only include the module we are writing and index for).
470           assert(ModuleToSummariesForIndex->size() == 1);
471           continue;
472         }
473         Callback(*MPI);
474       }
475     } else {
476       for (const auto &MPSE : Index.modulePaths())
477         Callback(MPSE);
478     }
479   }
480 
481   /// Main entry point for writing a combined index to bitcode.
482   void write();
483 
484 private:
485   void writeModStrings();
486   void writeCombinedGlobalValueSummary();
487 
488   Optional<unsigned> getValueId(GlobalValue::GUID ValGUID) {
489     auto VMI = GUIDToValueIdMap.find(ValGUID);
490     if (VMI == GUIDToValueIdMap.end())
491       return None;
492     return VMI->second;
493   }
494 
495   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
496 };
497 
498 } // end anonymous namespace
499 
500 static unsigned getEncodedCastOpcode(unsigned Opcode) {
501   switch (Opcode) {
502   default: llvm_unreachable("Unknown cast instruction!");
503   case Instruction::Trunc   : return bitc::CAST_TRUNC;
504   case Instruction::ZExt    : return bitc::CAST_ZEXT;
505   case Instruction::SExt    : return bitc::CAST_SEXT;
506   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
507   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
508   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
509   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
510   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
511   case Instruction::FPExt   : return bitc::CAST_FPEXT;
512   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
513   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
514   case Instruction::BitCast : return bitc::CAST_BITCAST;
515   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
516   }
517 }
518 
519 static unsigned getEncodedUnaryOpcode(unsigned Opcode) {
520   switch (Opcode) {
521   default: llvm_unreachable("Unknown binary instruction!");
522   case Instruction::FNeg: return bitc::UNOP_NEG;
523   }
524 }
525 
526 static unsigned getEncodedBinaryOpcode(unsigned Opcode) {
527   switch (Opcode) {
528   default: llvm_unreachable("Unknown binary instruction!");
529   case Instruction::Add:
530   case Instruction::FAdd: return bitc::BINOP_ADD;
531   case Instruction::Sub:
532   case Instruction::FSub: return bitc::BINOP_SUB;
533   case Instruction::Mul:
534   case Instruction::FMul: return bitc::BINOP_MUL;
535   case Instruction::UDiv: return bitc::BINOP_UDIV;
536   case Instruction::FDiv:
537   case Instruction::SDiv: return bitc::BINOP_SDIV;
538   case Instruction::URem: return bitc::BINOP_UREM;
539   case Instruction::FRem:
540   case Instruction::SRem: return bitc::BINOP_SREM;
541   case Instruction::Shl:  return bitc::BINOP_SHL;
542   case Instruction::LShr: return bitc::BINOP_LSHR;
543   case Instruction::AShr: return bitc::BINOP_ASHR;
544   case Instruction::And:  return bitc::BINOP_AND;
545   case Instruction::Or:   return bitc::BINOP_OR;
546   case Instruction::Xor:  return bitc::BINOP_XOR;
547   }
548 }
549 
550 static unsigned getEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
551   switch (Op) {
552   default: llvm_unreachable("Unknown RMW operation!");
553   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
554   case AtomicRMWInst::Add: return bitc::RMW_ADD;
555   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
556   case AtomicRMWInst::And: return bitc::RMW_AND;
557   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
558   case AtomicRMWInst::Or: return bitc::RMW_OR;
559   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
560   case AtomicRMWInst::Max: return bitc::RMW_MAX;
561   case AtomicRMWInst::Min: return bitc::RMW_MIN;
562   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
563   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
564   case AtomicRMWInst::FAdd: return bitc::RMW_FADD;
565   case AtomicRMWInst::FSub: return bitc::RMW_FSUB;
566   }
567 }
568 
569 static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
570   switch (Ordering) {
571   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
572   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
573   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
574   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
575   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
576   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
577   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
578   }
579   llvm_unreachable("Invalid ordering");
580 }
581 
582 static void writeStringRecord(BitstreamWriter &Stream, unsigned Code,
583                               StringRef Str, unsigned AbbrevToUse) {
584   SmallVector<unsigned, 64> Vals;
585 
586   // Code: [strchar x N]
587   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
588     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
589       AbbrevToUse = 0;
590     Vals.push_back(Str[i]);
591   }
592 
593   // Emit the finished record.
594   Stream.EmitRecord(Code, Vals, AbbrevToUse);
595 }
596 
597 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
598   switch (Kind) {
599   case Attribute::Alignment:
600     return bitc::ATTR_KIND_ALIGNMENT;
601   case Attribute::AllocSize:
602     return bitc::ATTR_KIND_ALLOC_SIZE;
603   case Attribute::AlwaysInline:
604     return bitc::ATTR_KIND_ALWAYS_INLINE;
605   case Attribute::ArgMemOnly:
606     return bitc::ATTR_KIND_ARGMEMONLY;
607   case Attribute::Builtin:
608     return bitc::ATTR_KIND_BUILTIN;
609   case Attribute::ByVal:
610     return bitc::ATTR_KIND_BY_VAL;
611   case Attribute::Convergent:
612     return bitc::ATTR_KIND_CONVERGENT;
613   case Attribute::InAlloca:
614     return bitc::ATTR_KIND_IN_ALLOCA;
615   case Attribute::Cold:
616     return bitc::ATTR_KIND_COLD;
617   case Attribute::InaccessibleMemOnly:
618     return bitc::ATTR_KIND_INACCESSIBLEMEM_ONLY;
619   case Attribute::InaccessibleMemOrArgMemOnly:
620     return bitc::ATTR_KIND_INACCESSIBLEMEM_OR_ARGMEMONLY;
621   case Attribute::InlineHint:
622     return bitc::ATTR_KIND_INLINE_HINT;
623   case Attribute::InReg:
624     return bitc::ATTR_KIND_IN_REG;
625   case Attribute::JumpTable:
626     return bitc::ATTR_KIND_JUMP_TABLE;
627   case Attribute::MinSize:
628     return bitc::ATTR_KIND_MIN_SIZE;
629   case Attribute::Naked:
630     return bitc::ATTR_KIND_NAKED;
631   case Attribute::Nest:
632     return bitc::ATTR_KIND_NEST;
633   case Attribute::NoAlias:
634     return bitc::ATTR_KIND_NO_ALIAS;
635   case Attribute::NoBuiltin:
636     return bitc::ATTR_KIND_NO_BUILTIN;
637   case Attribute::NoCapture:
638     return bitc::ATTR_KIND_NO_CAPTURE;
639   case Attribute::NoDuplicate:
640     return bitc::ATTR_KIND_NO_DUPLICATE;
641   case Attribute::NoImplicitFloat:
642     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
643   case Attribute::NoInline:
644     return bitc::ATTR_KIND_NO_INLINE;
645   case Attribute::NoRecurse:
646     return bitc::ATTR_KIND_NO_RECURSE;
647   case Attribute::NonLazyBind:
648     return bitc::ATTR_KIND_NON_LAZY_BIND;
649   case Attribute::NonNull:
650     return bitc::ATTR_KIND_NON_NULL;
651   case Attribute::Dereferenceable:
652     return bitc::ATTR_KIND_DEREFERENCEABLE;
653   case Attribute::DereferenceableOrNull:
654     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
655   case Attribute::NoRedZone:
656     return bitc::ATTR_KIND_NO_RED_ZONE;
657   case Attribute::NoReturn:
658     return bitc::ATTR_KIND_NO_RETURN;
659   case Attribute::NoCfCheck:
660     return bitc::ATTR_KIND_NOCF_CHECK;
661   case Attribute::NoUnwind:
662     return bitc::ATTR_KIND_NO_UNWIND;
663   case Attribute::OptForFuzzing:
664     return bitc::ATTR_KIND_OPT_FOR_FUZZING;
665   case Attribute::OptimizeForSize:
666     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
667   case Attribute::OptimizeNone:
668     return bitc::ATTR_KIND_OPTIMIZE_NONE;
669   case Attribute::ReadNone:
670     return bitc::ATTR_KIND_READ_NONE;
671   case Attribute::ReadOnly:
672     return bitc::ATTR_KIND_READ_ONLY;
673   case Attribute::Returned:
674     return bitc::ATTR_KIND_RETURNED;
675   case Attribute::ReturnsTwice:
676     return bitc::ATTR_KIND_RETURNS_TWICE;
677   case Attribute::SExt:
678     return bitc::ATTR_KIND_S_EXT;
679   case Attribute::Speculatable:
680     return bitc::ATTR_KIND_SPECULATABLE;
681   case Attribute::StackAlignment:
682     return bitc::ATTR_KIND_STACK_ALIGNMENT;
683   case Attribute::StackProtect:
684     return bitc::ATTR_KIND_STACK_PROTECT;
685   case Attribute::StackProtectReq:
686     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
687   case Attribute::StackProtectStrong:
688     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
689   case Attribute::SafeStack:
690     return bitc::ATTR_KIND_SAFESTACK;
691   case Attribute::ShadowCallStack:
692     return bitc::ATTR_KIND_SHADOWCALLSTACK;
693   case Attribute::StrictFP:
694     return bitc::ATTR_KIND_STRICT_FP;
695   case Attribute::StructRet:
696     return bitc::ATTR_KIND_STRUCT_RET;
697   case Attribute::SanitizeAddress:
698     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
699   case Attribute::SanitizeHWAddress:
700     return bitc::ATTR_KIND_SANITIZE_HWADDRESS;
701   case Attribute::SanitizeThread:
702     return bitc::ATTR_KIND_SANITIZE_THREAD;
703   case Attribute::SanitizeMemory:
704     return bitc::ATTR_KIND_SANITIZE_MEMORY;
705   case Attribute::SpeculativeLoadHardening:
706     return bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING;
707   case Attribute::SwiftError:
708     return bitc::ATTR_KIND_SWIFT_ERROR;
709   case Attribute::SwiftSelf:
710     return bitc::ATTR_KIND_SWIFT_SELF;
711   case Attribute::UWTable:
712     return bitc::ATTR_KIND_UW_TABLE;
713   case Attribute::WillReturn:
714     return bitc::ATTR_KIND_WILLRETURN;
715   case Attribute::WriteOnly:
716     return bitc::ATTR_KIND_WRITEONLY;
717   case Attribute::ZExt:
718     return bitc::ATTR_KIND_Z_EXT;
719   case Attribute::ImmArg:
720     return bitc::ATTR_KIND_IMMARG;
721   case Attribute::EndAttrKinds:
722     llvm_unreachable("Can not encode end-attribute kinds marker.");
723   case Attribute::None:
724     llvm_unreachable("Can not encode none-attribute.");
725   }
726 
727   llvm_unreachable("Trying to encode unknown attribute");
728 }
729 
730 void ModuleBitcodeWriter::writeAttributeGroupTable() {
731   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
732       VE.getAttributeGroups();
733   if (AttrGrps.empty()) return;
734 
735   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
736 
737   SmallVector<uint64_t, 64> Record;
738   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
739     unsigned AttrListIndex = Pair.first;
740     AttributeSet AS = Pair.second;
741     Record.push_back(VE.getAttributeGroupID(Pair));
742     Record.push_back(AttrListIndex);
743 
744     for (Attribute Attr : AS) {
745       if (Attr.isEnumAttribute()) {
746         Record.push_back(0);
747         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
748       } else if (Attr.isIntAttribute()) {
749         Record.push_back(1);
750         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
751         Record.push_back(Attr.getValueAsInt());
752       } else if (Attr.isStringAttribute()) {
753         StringRef Kind = Attr.getKindAsString();
754         StringRef Val = Attr.getValueAsString();
755 
756         Record.push_back(Val.empty() ? 3 : 4);
757         Record.append(Kind.begin(), Kind.end());
758         Record.push_back(0);
759         if (!Val.empty()) {
760           Record.append(Val.begin(), Val.end());
761           Record.push_back(0);
762         }
763       } else {
764         assert(Attr.isTypeAttribute());
765         Type *Ty = Attr.getValueAsType();
766         Record.push_back(Ty ? 6 : 5);
767         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
768         if (Ty)
769           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
770       }
771     }
772 
773     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
774     Record.clear();
775   }
776 
777   Stream.ExitBlock();
778 }
779 
780 void ModuleBitcodeWriter::writeAttributeTable() {
781   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
782   if (Attrs.empty()) return;
783 
784   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
785 
786   SmallVector<uint64_t, 64> Record;
787   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
788     AttributeList AL = Attrs[i];
789     for (unsigned i = AL.index_begin(), e = AL.index_end(); i != e; ++i) {
790       AttributeSet AS = AL.getAttributes(i);
791       if (AS.hasAttributes())
792         Record.push_back(VE.getAttributeGroupID({i, AS}));
793     }
794 
795     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
796     Record.clear();
797   }
798 
799   Stream.ExitBlock();
800 }
801 
802 /// WriteTypeTable - Write out the type table for a module.
803 void ModuleBitcodeWriter::writeTypeTable() {
804   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
805 
806   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
807   SmallVector<uint64_t, 64> TypeVals;
808 
809   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
810 
811   // Abbrev for TYPE_CODE_POINTER.
812   auto Abbv = std::make_shared<BitCodeAbbrev>();
813   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
814   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
815   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
816   unsigned PtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
817 
818   // Abbrev for TYPE_CODE_FUNCTION.
819   Abbv = std::make_shared<BitCodeAbbrev>();
820   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
821   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
822   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
823   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
824   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
825 
826   // Abbrev for TYPE_CODE_STRUCT_ANON.
827   Abbv = std::make_shared<BitCodeAbbrev>();
828   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
829   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
830   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
831   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
832   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
833 
834   // Abbrev for TYPE_CODE_STRUCT_NAME.
835   Abbv = std::make_shared<BitCodeAbbrev>();
836   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
837   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
838   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
839   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
840 
841   // Abbrev for TYPE_CODE_STRUCT_NAMED.
842   Abbv = std::make_shared<BitCodeAbbrev>();
843   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
844   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
845   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
846   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
847   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
848 
849   // Abbrev for TYPE_CODE_ARRAY.
850   Abbv = std::make_shared<BitCodeAbbrev>();
851   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
852   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
853   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
854   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
855 
856   // Emit an entry count so the reader can reserve space.
857   TypeVals.push_back(TypeList.size());
858   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
859   TypeVals.clear();
860 
861   // Loop over all of the types, emitting each in turn.
862   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
863     Type *T = TypeList[i];
864     int AbbrevToUse = 0;
865     unsigned Code = 0;
866 
867     switch (T->getTypeID()) {
868     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
869     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
870     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
871     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
872     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
873     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
874     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
875     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
876     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
877     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
878     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
879     case Type::IntegerTyID:
880       // INTEGER: [width]
881       Code = bitc::TYPE_CODE_INTEGER;
882       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
883       break;
884     case Type::PointerTyID: {
885       PointerType *PTy = cast<PointerType>(T);
886       // POINTER: [pointee type, address space]
887       Code = bitc::TYPE_CODE_POINTER;
888       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
889       unsigned AddressSpace = PTy->getAddressSpace();
890       TypeVals.push_back(AddressSpace);
891       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
892       break;
893     }
894     case Type::FunctionTyID: {
895       FunctionType *FT = cast<FunctionType>(T);
896       // FUNCTION: [isvararg, retty, paramty x N]
897       Code = bitc::TYPE_CODE_FUNCTION;
898       TypeVals.push_back(FT->isVarArg());
899       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
900       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
901         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
902       AbbrevToUse = FunctionAbbrev;
903       break;
904     }
905     case Type::StructTyID: {
906       StructType *ST = cast<StructType>(T);
907       // STRUCT: [ispacked, eltty x N]
908       TypeVals.push_back(ST->isPacked());
909       // Output all of the element types.
910       for (StructType::element_iterator I = ST->element_begin(),
911            E = ST->element_end(); I != E; ++I)
912         TypeVals.push_back(VE.getTypeID(*I));
913 
914       if (ST->isLiteral()) {
915         Code = bitc::TYPE_CODE_STRUCT_ANON;
916         AbbrevToUse = StructAnonAbbrev;
917       } else {
918         if (ST->isOpaque()) {
919           Code = bitc::TYPE_CODE_OPAQUE;
920         } else {
921           Code = bitc::TYPE_CODE_STRUCT_NAMED;
922           AbbrevToUse = StructNamedAbbrev;
923         }
924 
925         // Emit the name if it is present.
926         if (!ST->getName().empty())
927           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
928                             StructNameAbbrev);
929       }
930       break;
931     }
932     case Type::ArrayTyID: {
933       ArrayType *AT = cast<ArrayType>(T);
934       // ARRAY: [numelts, eltty]
935       Code = bitc::TYPE_CODE_ARRAY;
936       TypeVals.push_back(AT->getNumElements());
937       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
938       AbbrevToUse = ArrayAbbrev;
939       break;
940     }
941     case Type::VectorTyID: {
942       VectorType *VT = cast<VectorType>(T);
943       // VECTOR [numelts, eltty]
944       Code = bitc::TYPE_CODE_VECTOR;
945       TypeVals.push_back(VT->getNumElements());
946       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
947       break;
948     }
949     }
950 
951     // Emit the finished record.
952     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
953     TypeVals.clear();
954   }
955 
956   Stream.ExitBlock();
957 }
958 
959 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
960   switch (Linkage) {
961   case GlobalValue::ExternalLinkage:
962     return 0;
963   case GlobalValue::WeakAnyLinkage:
964     return 16;
965   case GlobalValue::AppendingLinkage:
966     return 2;
967   case GlobalValue::InternalLinkage:
968     return 3;
969   case GlobalValue::LinkOnceAnyLinkage:
970     return 18;
971   case GlobalValue::ExternalWeakLinkage:
972     return 7;
973   case GlobalValue::CommonLinkage:
974     return 8;
975   case GlobalValue::PrivateLinkage:
976     return 9;
977   case GlobalValue::WeakODRLinkage:
978     return 17;
979   case GlobalValue::LinkOnceODRLinkage:
980     return 19;
981   case GlobalValue::AvailableExternallyLinkage:
982     return 12;
983   }
984   llvm_unreachable("Invalid linkage");
985 }
986 
987 static unsigned getEncodedLinkage(const GlobalValue &GV) {
988   return getEncodedLinkage(GV.getLinkage());
989 }
990 
991 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
992   uint64_t RawFlags = 0;
993   RawFlags |= Flags.ReadNone;
994   RawFlags |= (Flags.ReadOnly << 1);
995   RawFlags |= (Flags.NoRecurse << 2);
996   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
997   RawFlags |= (Flags.NoInline << 4);
998   return RawFlags;
999 }
1000 
1001 // Decode the flags for GlobalValue in the summary
1002 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
1003   uint64_t RawFlags = 0;
1004 
1005   RawFlags |= Flags.NotEligibleToImport; // bool
1006   RawFlags |= (Flags.Live << 1);
1007   RawFlags |= (Flags.DSOLocal << 2);
1008   RawFlags |= (Flags.CanAutoHide << 3);
1009 
1010   // Linkage don't need to be remapped at that time for the summary. Any future
1011   // change to the getEncodedLinkage() function will need to be taken into
1012   // account here as well.
1013   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1014 
1015   return RawFlags;
1016 }
1017 
1018 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1019   uint64_t RawFlags = Flags.ReadOnly;
1020   return RawFlags;
1021 }
1022 
1023 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1024   switch (GV.getVisibility()) {
1025   case GlobalValue::DefaultVisibility:   return 0;
1026   case GlobalValue::HiddenVisibility:    return 1;
1027   case GlobalValue::ProtectedVisibility: return 2;
1028   }
1029   llvm_unreachable("Invalid visibility");
1030 }
1031 
1032 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1033   switch (GV.getDLLStorageClass()) {
1034   case GlobalValue::DefaultStorageClass:   return 0;
1035   case GlobalValue::DLLImportStorageClass: return 1;
1036   case GlobalValue::DLLExportStorageClass: return 2;
1037   }
1038   llvm_unreachable("Invalid DLL storage class");
1039 }
1040 
1041 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1042   switch (GV.getThreadLocalMode()) {
1043     case GlobalVariable::NotThreadLocal:         return 0;
1044     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1045     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1046     case GlobalVariable::InitialExecTLSModel:    return 3;
1047     case GlobalVariable::LocalExecTLSModel:      return 4;
1048   }
1049   llvm_unreachable("Invalid TLS model");
1050 }
1051 
1052 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1053   switch (C.getSelectionKind()) {
1054   case Comdat::Any:
1055     return bitc::COMDAT_SELECTION_KIND_ANY;
1056   case Comdat::ExactMatch:
1057     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1058   case Comdat::Largest:
1059     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1060   case Comdat::NoDuplicates:
1061     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1062   case Comdat::SameSize:
1063     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1064   }
1065   llvm_unreachable("Invalid selection kind");
1066 }
1067 
1068 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1069   switch (GV.getUnnamedAddr()) {
1070   case GlobalValue::UnnamedAddr::None:   return 0;
1071   case GlobalValue::UnnamedAddr::Local:  return 2;
1072   case GlobalValue::UnnamedAddr::Global: return 1;
1073   }
1074   llvm_unreachable("Invalid unnamed_addr");
1075 }
1076 
1077 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1078   if (GenerateHash)
1079     Hasher.update(Str);
1080   return StrtabBuilder.add(Str);
1081 }
1082 
1083 void ModuleBitcodeWriter::writeComdats() {
1084   SmallVector<unsigned, 64> Vals;
1085   for (const Comdat *C : VE.getComdats()) {
1086     // COMDAT: [strtab offset, strtab size, selection_kind]
1087     Vals.push_back(addToStrtab(C->getName()));
1088     Vals.push_back(C->getName().size());
1089     Vals.push_back(getEncodedComdatSelectionKind(*C));
1090     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1091     Vals.clear();
1092   }
1093 }
1094 
1095 /// Write a record that will eventually hold the word offset of the
1096 /// module-level VST. For now the offset is 0, which will be backpatched
1097 /// after the real VST is written. Saves the bit offset to backpatch.
1098 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1099   // Write a placeholder value in for the offset of the real VST,
1100   // which is written after the function blocks so that it can include
1101   // the offset of each function. The placeholder offset will be
1102   // updated when the real VST is written.
1103   auto Abbv = std::make_shared<BitCodeAbbrev>();
1104   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1105   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1106   // hold the real VST offset. Must use fixed instead of VBR as we don't
1107   // know how many VBR chunks to reserve ahead of time.
1108   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1109   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1110 
1111   // Emit the placeholder
1112   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1113   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1114 
1115   // Compute and save the bit offset to the placeholder, which will be
1116   // patched when the real VST is written. We can simply subtract the 32-bit
1117   // fixed size from the current bit number to get the location to backpatch.
1118   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1119 }
1120 
1121 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1122 
1123 /// Determine the encoding to use for the given string name and length.
1124 static StringEncoding getStringEncoding(StringRef Str) {
1125   bool isChar6 = true;
1126   for (char C : Str) {
1127     if (isChar6)
1128       isChar6 = BitCodeAbbrevOp::isChar6(C);
1129     if ((unsigned char)C & 128)
1130       // don't bother scanning the rest.
1131       return SE_Fixed8;
1132   }
1133   if (isChar6)
1134     return SE_Char6;
1135   return SE_Fixed7;
1136 }
1137 
1138 /// Emit top-level description of module, including target triple, inline asm,
1139 /// descriptors for global variables, and function prototype info.
1140 /// Returns the bit offset to backpatch with the location of the real VST.
1141 void ModuleBitcodeWriter::writeModuleInfo() {
1142   // Emit various pieces of data attached to a module.
1143   if (!M.getTargetTriple().empty())
1144     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1145                       0 /*TODO*/);
1146   const std::string &DL = M.getDataLayoutStr();
1147   if (!DL.empty())
1148     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1149   if (!M.getModuleInlineAsm().empty())
1150     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1151                       0 /*TODO*/);
1152 
1153   // Emit information about sections and GC, computing how many there are. Also
1154   // compute the maximum alignment value.
1155   std::map<std::string, unsigned> SectionMap;
1156   std::map<std::string, unsigned> GCMap;
1157   unsigned MaxAlignment = 0;
1158   unsigned MaxGlobalType = 0;
1159   for (const GlobalValue &GV : M.globals()) {
1160     MaxAlignment = std::max(MaxAlignment, GV.getAlignment());
1161     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1162     if (GV.hasSection()) {
1163       // Give section names unique ID's.
1164       unsigned &Entry = SectionMap[GV.getSection()];
1165       if (!Entry) {
1166         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1167                           0 /*TODO*/);
1168         Entry = SectionMap.size();
1169       }
1170     }
1171   }
1172   for (const Function &F : M) {
1173     MaxAlignment = std::max(MaxAlignment, F.getAlignment());
1174     if (F.hasSection()) {
1175       // Give section names unique ID's.
1176       unsigned &Entry = SectionMap[F.getSection()];
1177       if (!Entry) {
1178         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1179                           0 /*TODO*/);
1180         Entry = SectionMap.size();
1181       }
1182     }
1183     if (F.hasGC()) {
1184       // Same for GC names.
1185       unsigned &Entry = GCMap[F.getGC()];
1186       if (!Entry) {
1187         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1188                           0 /*TODO*/);
1189         Entry = GCMap.size();
1190       }
1191     }
1192   }
1193 
1194   // Emit abbrev for globals, now that we know # sections and max alignment.
1195   unsigned SimpleGVarAbbrev = 0;
1196   if (!M.global_empty()) {
1197     // Add an abbrev for common globals with no visibility or thread localness.
1198     auto Abbv = std::make_shared<BitCodeAbbrev>();
1199     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1200     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1201     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1202     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1203                               Log2_32_Ceil(MaxGlobalType+1)));
1204     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1205                                                            //| explicitType << 1
1206                                                            //| constant
1207     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1208     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1209     if (MaxAlignment == 0)                                 // Alignment.
1210       Abbv->Add(BitCodeAbbrevOp(0));
1211     else {
1212       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
1213       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1214                                Log2_32_Ceil(MaxEncAlignment+1)));
1215     }
1216     if (SectionMap.empty())                                    // Section.
1217       Abbv->Add(BitCodeAbbrevOp(0));
1218     else
1219       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1220                                Log2_32_Ceil(SectionMap.size()+1)));
1221     // Don't bother emitting vis + thread local.
1222     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1223   }
1224 
1225   SmallVector<unsigned, 64> Vals;
1226   // Emit the module's source file name.
1227   {
1228     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1229     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1230     if (Bits == SE_Char6)
1231       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1232     else if (Bits == SE_Fixed7)
1233       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1234 
1235     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1236     auto Abbv = std::make_shared<BitCodeAbbrev>();
1237     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1238     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1239     Abbv->Add(AbbrevOpToUse);
1240     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1241 
1242     for (const auto P : M.getSourceFileName())
1243       Vals.push_back((unsigned char)P);
1244 
1245     // Emit the finished record.
1246     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1247     Vals.clear();
1248   }
1249 
1250   // Emit the global variable information.
1251   for (const GlobalVariable &GV : M.globals()) {
1252     unsigned AbbrevToUse = 0;
1253 
1254     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1255     //             linkage, alignment, section, visibility, threadlocal,
1256     //             unnamed_addr, externally_initialized, dllstorageclass,
1257     //             comdat, attributes, DSO_Local]
1258     Vals.push_back(addToStrtab(GV.getName()));
1259     Vals.push_back(GV.getName().size());
1260     Vals.push_back(VE.getTypeID(GV.getValueType()));
1261     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1262     Vals.push_back(GV.isDeclaration() ? 0 :
1263                    (VE.getValueID(GV.getInitializer()) + 1));
1264     Vals.push_back(getEncodedLinkage(GV));
1265     Vals.push_back(Log2_32(GV.getAlignment())+1);
1266     Vals.push_back(GV.hasSection() ? SectionMap[GV.getSection()] : 0);
1267     if (GV.isThreadLocal() ||
1268         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1269         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1270         GV.isExternallyInitialized() ||
1271         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1272         GV.hasComdat() ||
1273         GV.hasAttributes() ||
1274         GV.isDSOLocal() ||
1275         GV.hasPartition()) {
1276       Vals.push_back(getEncodedVisibility(GV));
1277       Vals.push_back(getEncodedThreadLocalMode(GV));
1278       Vals.push_back(getEncodedUnnamedAddr(GV));
1279       Vals.push_back(GV.isExternallyInitialized());
1280       Vals.push_back(getEncodedDLLStorageClass(GV));
1281       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1282 
1283       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1284       Vals.push_back(VE.getAttributeListID(AL));
1285 
1286       Vals.push_back(GV.isDSOLocal());
1287       Vals.push_back(addToStrtab(GV.getPartition()));
1288       Vals.push_back(GV.getPartition().size());
1289     } else {
1290       AbbrevToUse = SimpleGVarAbbrev;
1291     }
1292 
1293     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1294     Vals.clear();
1295   }
1296 
1297   // Emit the function proto information.
1298   for (const Function &F : M) {
1299     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1300     //             linkage, paramattrs, alignment, section, visibility, gc,
1301     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1302     //             prefixdata, personalityfn, DSO_Local, addrspace]
1303     Vals.push_back(addToStrtab(F.getName()));
1304     Vals.push_back(F.getName().size());
1305     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1306     Vals.push_back(F.getCallingConv());
1307     Vals.push_back(F.isDeclaration());
1308     Vals.push_back(getEncodedLinkage(F));
1309     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1310     Vals.push_back(Log2_32(F.getAlignment())+1);
1311     Vals.push_back(F.hasSection() ? SectionMap[F.getSection()] : 0);
1312     Vals.push_back(getEncodedVisibility(F));
1313     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1314     Vals.push_back(getEncodedUnnamedAddr(F));
1315     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1316                                        : 0);
1317     Vals.push_back(getEncodedDLLStorageClass(F));
1318     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1319     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1320                                      : 0);
1321     Vals.push_back(
1322         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1323 
1324     Vals.push_back(F.isDSOLocal());
1325     Vals.push_back(F.getAddressSpace());
1326     Vals.push_back(addToStrtab(F.getPartition()));
1327     Vals.push_back(F.getPartition().size());
1328 
1329     unsigned AbbrevToUse = 0;
1330     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1331     Vals.clear();
1332   }
1333 
1334   // Emit the alias information.
1335   for (const GlobalAlias &A : M.aliases()) {
1336     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1337     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1338     //         DSO_Local]
1339     Vals.push_back(addToStrtab(A.getName()));
1340     Vals.push_back(A.getName().size());
1341     Vals.push_back(VE.getTypeID(A.getValueType()));
1342     Vals.push_back(A.getType()->getAddressSpace());
1343     Vals.push_back(VE.getValueID(A.getAliasee()));
1344     Vals.push_back(getEncodedLinkage(A));
1345     Vals.push_back(getEncodedVisibility(A));
1346     Vals.push_back(getEncodedDLLStorageClass(A));
1347     Vals.push_back(getEncodedThreadLocalMode(A));
1348     Vals.push_back(getEncodedUnnamedAddr(A));
1349     Vals.push_back(A.isDSOLocal());
1350     Vals.push_back(addToStrtab(A.getPartition()));
1351     Vals.push_back(A.getPartition().size());
1352 
1353     unsigned AbbrevToUse = 0;
1354     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1355     Vals.clear();
1356   }
1357 
1358   // Emit the ifunc information.
1359   for (const GlobalIFunc &I : M.ifuncs()) {
1360     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1361     //         val#, linkage, visibility, DSO_Local]
1362     Vals.push_back(addToStrtab(I.getName()));
1363     Vals.push_back(I.getName().size());
1364     Vals.push_back(VE.getTypeID(I.getValueType()));
1365     Vals.push_back(I.getType()->getAddressSpace());
1366     Vals.push_back(VE.getValueID(I.getResolver()));
1367     Vals.push_back(getEncodedLinkage(I));
1368     Vals.push_back(getEncodedVisibility(I));
1369     Vals.push_back(I.isDSOLocal());
1370     Vals.push_back(addToStrtab(I.getPartition()));
1371     Vals.push_back(I.getPartition().size());
1372     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1373     Vals.clear();
1374   }
1375 
1376   writeValueSymbolTableForwardDecl();
1377 }
1378 
1379 static uint64_t getOptimizationFlags(const Value *V) {
1380   uint64_t Flags = 0;
1381 
1382   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1383     if (OBO->hasNoSignedWrap())
1384       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1385     if (OBO->hasNoUnsignedWrap())
1386       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1387   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1388     if (PEO->isExact())
1389       Flags |= 1 << bitc::PEO_EXACT;
1390   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1391     if (FPMO->hasAllowReassoc())
1392       Flags |= bitc::AllowReassoc;
1393     if (FPMO->hasNoNaNs())
1394       Flags |= bitc::NoNaNs;
1395     if (FPMO->hasNoInfs())
1396       Flags |= bitc::NoInfs;
1397     if (FPMO->hasNoSignedZeros())
1398       Flags |= bitc::NoSignedZeros;
1399     if (FPMO->hasAllowReciprocal())
1400       Flags |= bitc::AllowReciprocal;
1401     if (FPMO->hasAllowContract())
1402       Flags |= bitc::AllowContract;
1403     if (FPMO->hasApproxFunc())
1404       Flags |= bitc::ApproxFunc;
1405   }
1406 
1407   return Flags;
1408 }
1409 
1410 void ModuleBitcodeWriter::writeValueAsMetadata(
1411     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1412   // Mimic an MDNode with a value as one operand.
1413   Value *V = MD->getValue();
1414   Record.push_back(VE.getTypeID(V->getType()));
1415   Record.push_back(VE.getValueID(V));
1416   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1417   Record.clear();
1418 }
1419 
1420 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1421                                        SmallVectorImpl<uint64_t> &Record,
1422                                        unsigned Abbrev) {
1423   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1424     Metadata *MD = N->getOperand(i);
1425     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1426            "Unexpected function-local metadata");
1427     Record.push_back(VE.getMetadataOrNullID(MD));
1428   }
1429   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1430                                     : bitc::METADATA_NODE,
1431                     Record, Abbrev);
1432   Record.clear();
1433 }
1434 
1435 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1436   // Assume the column is usually under 128, and always output the inlined-at
1437   // location (it's never more expensive than building an array size 1).
1438   auto Abbv = std::make_shared<BitCodeAbbrev>();
1439   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1440   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1441   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1442   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1443   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1444   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1445   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1446   return Stream.EmitAbbrev(std::move(Abbv));
1447 }
1448 
1449 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1450                                           SmallVectorImpl<uint64_t> &Record,
1451                                           unsigned &Abbrev) {
1452   if (!Abbrev)
1453     Abbrev = createDILocationAbbrev();
1454 
1455   Record.push_back(N->isDistinct());
1456   Record.push_back(N->getLine());
1457   Record.push_back(N->getColumn());
1458   Record.push_back(VE.getMetadataID(N->getScope()));
1459   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1460   Record.push_back(N->isImplicitCode());
1461 
1462   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1463   Record.clear();
1464 }
1465 
1466 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1467   // Assume the column is usually under 128, and always output the inlined-at
1468   // location (it's never more expensive than building an array size 1).
1469   auto Abbv = std::make_shared<BitCodeAbbrev>();
1470   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1471   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1472   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1473   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1474   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1475   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1476   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1477   return Stream.EmitAbbrev(std::move(Abbv));
1478 }
1479 
1480 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1481                                              SmallVectorImpl<uint64_t> &Record,
1482                                              unsigned &Abbrev) {
1483   if (!Abbrev)
1484     Abbrev = createGenericDINodeAbbrev();
1485 
1486   Record.push_back(N->isDistinct());
1487   Record.push_back(N->getTag());
1488   Record.push_back(0); // Per-tag version field; unused for now.
1489 
1490   for (auto &I : N->operands())
1491     Record.push_back(VE.getMetadataOrNullID(I));
1492 
1493   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1494   Record.clear();
1495 }
1496 
1497 static uint64_t rotateSign(int64_t I) {
1498   uint64_t U = I;
1499   return I < 0 ? ~(U << 1) : U << 1;
1500 }
1501 
1502 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1503                                           SmallVectorImpl<uint64_t> &Record,
1504                                           unsigned Abbrev) {
1505   const uint64_t Version = 1 << 1;
1506   Record.push_back((uint64_t)N->isDistinct() | Version);
1507   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1508   Record.push_back(rotateSign(N->getLowerBound()));
1509 
1510   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1511   Record.clear();
1512 }
1513 
1514 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1515                                             SmallVectorImpl<uint64_t> &Record,
1516                                             unsigned Abbrev) {
1517   Record.push_back((N->isUnsigned() << 1) | N->isDistinct());
1518   Record.push_back(rotateSign(N->getValue()));
1519   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1520 
1521   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1522   Record.clear();
1523 }
1524 
1525 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1526                                            SmallVectorImpl<uint64_t> &Record,
1527                                            unsigned Abbrev) {
1528   Record.push_back(N->isDistinct());
1529   Record.push_back(N->getTag());
1530   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1531   Record.push_back(N->getSizeInBits());
1532   Record.push_back(N->getAlignInBits());
1533   Record.push_back(N->getEncoding());
1534   Record.push_back(N->getFlags());
1535 
1536   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1537   Record.clear();
1538 }
1539 
1540 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1541                                              SmallVectorImpl<uint64_t> &Record,
1542                                              unsigned Abbrev) {
1543   Record.push_back(N->isDistinct());
1544   Record.push_back(N->getTag());
1545   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1546   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1547   Record.push_back(N->getLine());
1548   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1549   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1550   Record.push_back(N->getSizeInBits());
1551   Record.push_back(N->getAlignInBits());
1552   Record.push_back(N->getOffsetInBits());
1553   Record.push_back(N->getFlags());
1554   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1555 
1556   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1557   // that there is no DWARF address space associated with DIDerivedType.
1558   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1559     Record.push_back(*DWARFAddressSpace + 1);
1560   else
1561     Record.push_back(0);
1562 
1563   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1564   Record.clear();
1565 }
1566 
1567 void ModuleBitcodeWriter::writeDICompositeType(
1568     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1569     unsigned Abbrev) {
1570   const unsigned IsNotUsedInOldTypeRef = 0x2;
1571   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1572   Record.push_back(N->getTag());
1573   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1574   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1575   Record.push_back(N->getLine());
1576   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1577   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1578   Record.push_back(N->getSizeInBits());
1579   Record.push_back(N->getAlignInBits());
1580   Record.push_back(N->getOffsetInBits());
1581   Record.push_back(N->getFlags());
1582   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1583   Record.push_back(N->getRuntimeLang());
1584   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1585   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1586   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1587   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1588 
1589   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1590   Record.clear();
1591 }
1592 
1593 void ModuleBitcodeWriter::writeDISubroutineType(
1594     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1595     unsigned Abbrev) {
1596   const unsigned HasNoOldTypeRefs = 0x2;
1597   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1598   Record.push_back(N->getFlags());
1599   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1600   Record.push_back(N->getCC());
1601 
1602   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1603   Record.clear();
1604 }
1605 
1606 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1607                                       SmallVectorImpl<uint64_t> &Record,
1608                                       unsigned Abbrev) {
1609   Record.push_back(N->isDistinct());
1610   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1611   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1612   if (N->getRawChecksum()) {
1613     Record.push_back(N->getRawChecksum()->Kind);
1614     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1615   } else {
1616     // Maintain backwards compatibility with the old internal representation of
1617     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1618     Record.push_back(0);
1619     Record.push_back(VE.getMetadataOrNullID(nullptr));
1620   }
1621   auto Source = N->getRawSource();
1622   if (Source)
1623     Record.push_back(VE.getMetadataOrNullID(*Source));
1624 
1625   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1626   Record.clear();
1627 }
1628 
1629 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1630                                              SmallVectorImpl<uint64_t> &Record,
1631                                              unsigned Abbrev) {
1632   assert(N->isDistinct() && "Expected distinct compile units");
1633   Record.push_back(/* IsDistinct */ true);
1634   Record.push_back(N->getSourceLanguage());
1635   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1636   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1637   Record.push_back(N->isOptimized());
1638   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1639   Record.push_back(N->getRuntimeVersion());
1640   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1641   Record.push_back(N->getEmissionKind());
1642   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1643   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1644   Record.push_back(/* subprograms */ 0);
1645   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1646   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1647   Record.push_back(N->getDWOId());
1648   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1649   Record.push_back(N->getSplitDebugInlining());
1650   Record.push_back(N->getDebugInfoForProfiling());
1651   Record.push_back((unsigned)N->getNameTableKind());
1652 
1653   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1654   Record.clear();
1655 }
1656 
1657 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1658                                             SmallVectorImpl<uint64_t> &Record,
1659                                             unsigned Abbrev) {
1660   const uint64_t HasUnitFlag = 1 << 1;
1661   const uint64_t HasSPFlagsFlag = 1 << 2;
1662   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
1663   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1664   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1665   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1666   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1667   Record.push_back(N->getLine());
1668   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1669   Record.push_back(N->getScopeLine());
1670   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1671   Record.push_back(N->getSPFlags());
1672   Record.push_back(N->getVirtualIndex());
1673   Record.push_back(N->getFlags());
1674   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1675   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1676   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1677   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
1678   Record.push_back(N->getThisAdjustment());
1679   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
1680 
1681   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1682   Record.clear();
1683 }
1684 
1685 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1686                                               SmallVectorImpl<uint64_t> &Record,
1687                                               unsigned Abbrev) {
1688   Record.push_back(N->isDistinct());
1689   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1690   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1691   Record.push_back(N->getLine());
1692   Record.push_back(N->getColumn());
1693 
1694   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1695   Record.clear();
1696 }
1697 
1698 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1699     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1700     unsigned Abbrev) {
1701   Record.push_back(N->isDistinct());
1702   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1703   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1704   Record.push_back(N->getDiscriminator());
1705 
1706   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1707   Record.clear();
1708 }
1709 
1710 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
1711                                              SmallVectorImpl<uint64_t> &Record,
1712                                              unsigned Abbrev) {
1713   Record.push_back(N->isDistinct());
1714   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1715   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
1716   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1717   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1718   Record.push_back(N->getLineNo());
1719 
1720   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
1721   Record.clear();
1722 }
1723 
1724 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1725                                            SmallVectorImpl<uint64_t> &Record,
1726                                            unsigned Abbrev) {
1727   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1728   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1729   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1730 
1731   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1732   Record.clear();
1733 }
1734 
1735 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1736                                        SmallVectorImpl<uint64_t> &Record,
1737                                        unsigned Abbrev) {
1738   Record.push_back(N->isDistinct());
1739   Record.push_back(N->getMacinfoType());
1740   Record.push_back(N->getLine());
1741   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1742   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1743 
1744   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1745   Record.clear();
1746 }
1747 
1748 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1749                                            SmallVectorImpl<uint64_t> &Record,
1750                                            unsigned Abbrev) {
1751   Record.push_back(N->isDistinct());
1752   Record.push_back(N->getMacinfoType());
1753   Record.push_back(N->getLine());
1754   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1755   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1756 
1757   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1758   Record.clear();
1759 }
1760 
1761 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1762                                         SmallVectorImpl<uint64_t> &Record,
1763                                         unsigned Abbrev) {
1764   Record.push_back(N->isDistinct());
1765   for (auto &I : N->operands())
1766     Record.push_back(VE.getMetadataOrNullID(I));
1767 
1768   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1769   Record.clear();
1770 }
1771 
1772 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1773     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1774     unsigned Abbrev) {
1775   Record.push_back(N->isDistinct());
1776   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1777   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1778 
1779   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1780   Record.clear();
1781 }
1782 
1783 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1784     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1785     unsigned Abbrev) {
1786   Record.push_back(N->isDistinct());
1787   Record.push_back(N->getTag());
1788   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1789   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1790   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1791 
1792   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1793   Record.clear();
1794 }
1795 
1796 void ModuleBitcodeWriter::writeDIGlobalVariable(
1797     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1798     unsigned Abbrev) {
1799   const uint64_t Version = 2 << 1;
1800   Record.push_back((uint64_t)N->isDistinct() | Version);
1801   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1802   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1803   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1804   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1805   Record.push_back(N->getLine());
1806   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1807   Record.push_back(N->isLocalToUnit());
1808   Record.push_back(N->isDefinition());
1809   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1810   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
1811   Record.push_back(N->getAlignInBits());
1812 
1813   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1814   Record.clear();
1815 }
1816 
1817 void ModuleBitcodeWriter::writeDILocalVariable(
1818     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
1819     unsigned Abbrev) {
1820   // In order to support all possible bitcode formats in BitcodeReader we need
1821   // to distinguish the following cases:
1822   // 1) Record has no artificial tag (Record[1]),
1823   //   has no obsolete inlinedAt field (Record[9]).
1824   //   In this case Record size will be 8, HasAlignment flag is false.
1825   // 2) Record has artificial tag (Record[1]),
1826   //   has no obsolete inlignedAt field (Record[9]).
1827   //   In this case Record size will be 9, HasAlignment flag is false.
1828   // 3) Record has both artificial tag (Record[1]) and
1829   //   obsolete inlignedAt field (Record[9]).
1830   //   In this case Record size will be 10, HasAlignment flag is false.
1831   // 4) Record has neither artificial tag, nor inlignedAt field, but
1832   //   HasAlignment flag is true and Record[8] contains alignment value.
1833   const uint64_t HasAlignmentFlag = 1 << 1;
1834   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
1835   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1836   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1837   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1838   Record.push_back(N->getLine());
1839   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1840   Record.push_back(N->getArg());
1841   Record.push_back(N->getFlags());
1842   Record.push_back(N->getAlignInBits());
1843 
1844   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1845   Record.clear();
1846 }
1847 
1848 void ModuleBitcodeWriter::writeDILabel(
1849     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
1850     unsigned Abbrev) {
1851   Record.push_back((uint64_t)N->isDistinct());
1852   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1853   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1854   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1855   Record.push_back(N->getLine());
1856 
1857   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
1858   Record.clear();
1859 }
1860 
1861 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
1862                                             SmallVectorImpl<uint64_t> &Record,
1863                                             unsigned Abbrev) {
1864   Record.reserve(N->getElements().size() + 1);
1865   const uint64_t Version = 3 << 1;
1866   Record.push_back((uint64_t)N->isDistinct() | Version);
1867   Record.append(N->elements_begin(), N->elements_end());
1868 
1869   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
1870   Record.clear();
1871 }
1872 
1873 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
1874     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
1875     unsigned Abbrev) {
1876   Record.push_back(N->isDistinct());
1877   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
1878   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
1879 
1880   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
1881   Record.clear();
1882 }
1883 
1884 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
1885                                               SmallVectorImpl<uint64_t> &Record,
1886                                               unsigned Abbrev) {
1887   Record.push_back(N->isDistinct());
1888   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1889   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1890   Record.push_back(N->getLine());
1891   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
1892   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
1893   Record.push_back(N->getAttributes());
1894   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1895 
1896   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
1897   Record.clear();
1898 }
1899 
1900 void ModuleBitcodeWriter::writeDIImportedEntity(
1901     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
1902     unsigned Abbrev) {
1903   Record.push_back(N->isDistinct());
1904   Record.push_back(N->getTag());
1905   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1906   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
1907   Record.push_back(N->getLine());
1908   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1909   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
1910 
1911   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
1912   Record.clear();
1913 }
1914 
1915 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
1916   auto Abbv = std::make_shared<BitCodeAbbrev>();
1917   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
1918   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1919   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1920   return Stream.EmitAbbrev(std::move(Abbv));
1921 }
1922 
1923 void ModuleBitcodeWriter::writeNamedMetadata(
1924     SmallVectorImpl<uint64_t> &Record) {
1925   if (M.named_metadata_empty())
1926     return;
1927 
1928   unsigned Abbrev = createNamedMetadataAbbrev();
1929   for (const NamedMDNode &NMD : M.named_metadata()) {
1930     // Write name.
1931     StringRef Str = NMD.getName();
1932     Record.append(Str.bytes_begin(), Str.bytes_end());
1933     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
1934     Record.clear();
1935 
1936     // Write named metadata operands.
1937     for (const MDNode *N : NMD.operands())
1938       Record.push_back(VE.getMetadataID(N));
1939     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
1940     Record.clear();
1941   }
1942 }
1943 
1944 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
1945   auto Abbv = std::make_shared<BitCodeAbbrev>();
1946   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
1947   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
1948   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
1949   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
1950   return Stream.EmitAbbrev(std::move(Abbv));
1951 }
1952 
1953 /// Write out a record for MDString.
1954 ///
1955 /// All the metadata strings in a metadata block are emitted in a single
1956 /// record.  The sizes and strings themselves are shoved into a blob.
1957 void ModuleBitcodeWriter::writeMetadataStrings(
1958     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
1959   if (Strings.empty())
1960     return;
1961 
1962   // Start the record with the number of strings.
1963   Record.push_back(bitc::METADATA_STRINGS);
1964   Record.push_back(Strings.size());
1965 
1966   // Emit the sizes of the strings in the blob.
1967   SmallString<256> Blob;
1968   {
1969     BitstreamWriter W(Blob);
1970     for (const Metadata *MD : Strings)
1971       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
1972     W.FlushToWord();
1973   }
1974 
1975   // Add the offset to the strings to the record.
1976   Record.push_back(Blob.size());
1977 
1978   // Add the strings to the blob.
1979   for (const Metadata *MD : Strings)
1980     Blob.append(cast<MDString>(MD)->getString());
1981 
1982   // Emit the final record.
1983   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
1984   Record.clear();
1985 }
1986 
1987 // Generates an enum to use as an index in the Abbrev array of Metadata record.
1988 enum MetadataAbbrev : unsigned {
1989 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
1990 #include "llvm/IR/Metadata.def"
1991   LastPlusOne
1992 };
1993 
1994 void ModuleBitcodeWriter::writeMetadataRecords(
1995     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
1996     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
1997   if (MDs.empty())
1998     return;
1999 
2000   // Initialize MDNode abbreviations.
2001 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2002 #include "llvm/IR/Metadata.def"
2003 
2004   for (const Metadata *MD : MDs) {
2005     if (IndexPos)
2006       IndexPos->push_back(Stream.GetCurrentBitNo());
2007     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2008       assert(N->isResolved() && "Expected forward references to be resolved");
2009 
2010       switch (N->getMetadataID()) {
2011       default:
2012         llvm_unreachable("Invalid MDNode subclass");
2013 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2014   case Metadata::CLASS##Kind:                                                  \
2015     if (MDAbbrevs)                                                             \
2016       write##CLASS(cast<CLASS>(N), Record,                                     \
2017                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2018     else                                                                       \
2019       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2020     continue;
2021 #include "llvm/IR/Metadata.def"
2022       }
2023     }
2024     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2025   }
2026 }
2027 
2028 void ModuleBitcodeWriter::writeModuleMetadata() {
2029   if (!VE.hasMDs() && M.named_metadata_empty())
2030     return;
2031 
2032   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2033   SmallVector<uint64_t, 64> Record;
2034 
2035   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2036   // block and load any metadata.
2037   std::vector<unsigned> MDAbbrevs;
2038 
2039   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2040   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2041   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2042       createGenericDINodeAbbrev();
2043 
2044   auto Abbv = std::make_shared<BitCodeAbbrev>();
2045   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2046   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2047   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2048   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2049 
2050   Abbv = std::make_shared<BitCodeAbbrev>();
2051   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2052   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2053   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2054   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2055 
2056   // Emit MDStrings together upfront.
2057   writeMetadataStrings(VE.getMDStrings(), Record);
2058 
2059   // We only emit an index for the metadata record if we have more than a given
2060   // (naive) threshold of metadatas, otherwise it is not worth it.
2061   if (VE.getNonMDStrings().size() > IndexThreshold) {
2062     // Write a placeholder value in for the offset of the metadata index,
2063     // which is written after the records, so that it can include
2064     // the offset of each entry. The placeholder offset will be
2065     // updated after all records are emitted.
2066     uint64_t Vals[] = {0, 0};
2067     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2068   }
2069 
2070   // Compute and save the bit offset to the current position, which will be
2071   // patched when we emit the index later. We can simply subtract the 64-bit
2072   // fixed size from the current bit number to get the location to backpatch.
2073   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2074 
2075   // This index will contain the bitpos for each individual record.
2076   std::vector<uint64_t> IndexPos;
2077   IndexPos.reserve(VE.getNonMDStrings().size());
2078 
2079   // Write all the records
2080   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2081 
2082   if (VE.getNonMDStrings().size() > IndexThreshold) {
2083     // Now that we have emitted all the records we will emit the index. But
2084     // first
2085     // backpatch the forward reference so that the reader can skip the records
2086     // efficiently.
2087     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2088                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2089 
2090     // Delta encode the index.
2091     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2092     for (auto &Elt : IndexPos) {
2093       auto EltDelta = Elt - PreviousValue;
2094       PreviousValue = Elt;
2095       Elt = EltDelta;
2096     }
2097     // Emit the index record.
2098     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2099     IndexPos.clear();
2100   }
2101 
2102   // Write the named metadata now.
2103   writeNamedMetadata(Record);
2104 
2105   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2106     SmallVector<uint64_t, 4> Record;
2107     Record.push_back(VE.getValueID(&GO));
2108     pushGlobalMetadataAttachment(Record, GO);
2109     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2110   };
2111   for (const Function &F : M)
2112     if (F.isDeclaration() && F.hasMetadata())
2113       AddDeclAttachedMetadata(F);
2114   // FIXME: Only store metadata for declarations here, and move data for global
2115   // variable definitions to a separate block (PR28134).
2116   for (const GlobalVariable &GV : M.globals())
2117     if (GV.hasMetadata())
2118       AddDeclAttachedMetadata(GV);
2119 
2120   Stream.ExitBlock();
2121 }
2122 
2123 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2124   if (!VE.hasMDs())
2125     return;
2126 
2127   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2128   SmallVector<uint64_t, 64> Record;
2129   writeMetadataStrings(VE.getMDStrings(), Record);
2130   writeMetadataRecords(VE.getNonMDStrings(), Record);
2131   Stream.ExitBlock();
2132 }
2133 
2134 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2135     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2136   // [n x [id, mdnode]]
2137   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2138   GO.getAllMetadata(MDs);
2139   for (const auto &I : MDs) {
2140     Record.push_back(I.first);
2141     Record.push_back(VE.getMetadataID(I.second));
2142   }
2143 }
2144 
2145 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2146   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2147 
2148   SmallVector<uint64_t, 64> Record;
2149 
2150   if (F.hasMetadata()) {
2151     pushGlobalMetadataAttachment(Record, F);
2152     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2153     Record.clear();
2154   }
2155 
2156   // Write metadata attachments
2157   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2158   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2159   for (const BasicBlock &BB : F)
2160     for (const Instruction &I : BB) {
2161       MDs.clear();
2162       I.getAllMetadataOtherThanDebugLoc(MDs);
2163 
2164       // If no metadata, ignore instruction.
2165       if (MDs.empty()) continue;
2166 
2167       Record.push_back(VE.getInstructionID(&I));
2168 
2169       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2170         Record.push_back(MDs[i].first);
2171         Record.push_back(VE.getMetadataID(MDs[i].second));
2172       }
2173       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2174       Record.clear();
2175     }
2176 
2177   Stream.ExitBlock();
2178 }
2179 
2180 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2181   SmallVector<uint64_t, 64> Record;
2182 
2183   // Write metadata kinds
2184   // METADATA_KIND - [n x [id, name]]
2185   SmallVector<StringRef, 8> Names;
2186   M.getMDKindNames(Names);
2187 
2188   if (Names.empty()) return;
2189 
2190   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2191 
2192   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2193     Record.push_back(MDKindID);
2194     StringRef KName = Names[MDKindID];
2195     Record.append(KName.begin(), KName.end());
2196 
2197     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2198     Record.clear();
2199   }
2200 
2201   Stream.ExitBlock();
2202 }
2203 
2204 void ModuleBitcodeWriter::writeOperandBundleTags() {
2205   // Write metadata kinds
2206   //
2207   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2208   //
2209   // OPERAND_BUNDLE_TAG - [strchr x N]
2210 
2211   SmallVector<StringRef, 8> Tags;
2212   M.getOperandBundleTags(Tags);
2213 
2214   if (Tags.empty())
2215     return;
2216 
2217   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2218 
2219   SmallVector<uint64_t, 64> Record;
2220 
2221   for (auto Tag : Tags) {
2222     Record.append(Tag.begin(), Tag.end());
2223 
2224     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2225     Record.clear();
2226   }
2227 
2228   Stream.ExitBlock();
2229 }
2230 
2231 void ModuleBitcodeWriter::writeSyncScopeNames() {
2232   SmallVector<StringRef, 8> SSNs;
2233   M.getContext().getSyncScopeNames(SSNs);
2234   if (SSNs.empty())
2235     return;
2236 
2237   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2238 
2239   SmallVector<uint64_t, 64> Record;
2240   for (auto SSN : SSNs) {
2241     Record.append(SSN.begin(), SSN.end());
2242     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2243     Record.clear();
2244   }
2245 
2246   Stream.ExitBlock();
2247 }
2248 
2249 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
2250   if ((int64_t)V >= 0)
2251     Vals.push_back(V << 1);
2252   else
2253     Vals.push_back((-V << 1) | 1);
2254 }
2255 
2256 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2257                                          bool isGlobal) {
2258   if (FirstVal == LastVal) return;
2259 
2260   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2261 
2262   unsigned AggregateAbbrev = 0;
2263   unsigned String8Abbrev = 0;
2264   unsigned CString7Abbrev = 0;
2265   unsigned CString6Abbrev = 0;
2266   // If this is a constant pool for the module, emit module-specific abbrevs.
2267   if (isGlobal) {
2268     // Abbrev for CST_CODE_AGGREGATE.
2269     auto Abbv = std::make_shared<BitCodeAbbrev>();
2270     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2271     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2272     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2273     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2274 
2275     // Abbrev for CST_CODE_STRING.
2276     Abbv = std::make_shared<BitCodeAbbrev>();
2277     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2278     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2279     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2280     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2281     // Abbrev for CST_CODE_CSTRING.
2282     Abbv = std::make_shared<BitCodeAbbrev>();
2283     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2284     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2285     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2286     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2287     // Abbrev for CST_CODE_CSTRING.
2288     Abbv = std::make_shared<BitCodeAbbrev>();
2289     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2290     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2291     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2292     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2293   }
2294 
2295   SmallVector<uint64_t, 64> Record;
2296 
2297   const ValueEnumerator::ValueList &Vals = VE.getValues();
2298   Type *LastTy = nullptr;
2299   for (unsigned i = FirstVal; i != LastVal; ++i) {
2300     const Value *V = Vals[i].first;
2301     // If we need to switch types, do so now.
2302     if (V->getType() != LastTy) {
2303       LastTy = V->getType();
2304       Record.push_back(VE.getTypeID(LastTy));
2305       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2306                         CONSTANTS_SETTYPE_ABBREV);
2307       Record.clear();
2308     }
2309 
2310     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2311       Record.push_back(unsigned(IA->hasSideEffects()) |
2312                        unsigned(IA->isAlignStack()) << 1 |
2313                        unsigned(IA->getDialect()&1) << 2);
2314 
2315       // Add the asm string.
2316       const std::string &AsmStr = IA->getAsmString();
2317       Record.push_back(AsmStr.size());
2318       Record.append(AsmStr.begin(), AsmStr.end());
2319 
2320       // Add the constraint string.
2321       const std::string &ConstraintStr = IA->getConstraintString();
2322       Record.push_back(ConstraintStr.size());
2323       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2324       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2325       Record.clear();
2326       continue;
2327     }
2328     const Constant *C = cast<Constant>(V);
2329     unsigned Code = -1U;
2330     unsigned AbbrevToUse = 0;
2331     if (C->isNullValue()) {
2332       Code = bitc::CST_CODE_NULL;
2333     } else if (isa<UndefValue>(C)) {
2334       Code = bitc::CST_CODE_UNDEF;
2335     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2336       if (IV->getBitWidth() <= 64) {
2337         uint64_t V = IV->getSExtValue();
2338         emitSignedInt64(Record, V);
2339         Code = bitc::CST_CODE_INTEGER;
2340         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2341       } else {                             // Wide integers, > 64 bits in size.
2342         // We have an arbitrary precision integer value to write whose
2343         // bit width is > 64. However, in canonical unsigned integer
2344         // format it is likely that the high bits are going to be zero.
2345         // So, we only write the number of active words.
2346         unsigned NWords = IV->getValue().getActiveWords();
2347         const uint64_t *RawWords = IV->getValue().getRawData();
2348         for (unsigned i = 0; i != NWords; ++i) {
2349           emitSignedInt64(Record, RawWords[i]);
2350         }
2351         Code = bitc::CST_CODE_WIDE_INTEGER;
2352       }
2353     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2354       Code = bitc::CST_CODE_FLOAT;
2355       Type *Ty = CFP->getType();
2356       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
2357         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2358       } else if (Ty->isX86_FP80Ty()) {
2359         // api needed to prevent premature destruction
2360         // bits are not in the same order as a normal i80 APInt, compensate.
2361         APInt api = CFP->getValueAPF().bitcastToAPInt();
2362         const uint64_t *p = api.getRawData();
2363         Record.push_back((p[1] << 48) | (p[0] >> 16));
2364         Record.push_back(p[0] & 0xffffLL);
2365       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2366         APInt api = CFP->getValueAPF().bitcastToAPInt();
2367         const uint64_t *p = api.getRawData();
2368         Record.push_back(p[0]);
2369         Record.push_back(p[1]);
2370       } else {
2371         assert(0 && "Unknown FP type!");
2372       }
2373     } else if (isa<ConstantDataSequential>(C) &&
2374                cast<ConstantDataSequential>(C)->isString()) {
2375       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2376       // Emit constant strings specially.
2377       unsigned NumElts = Str->getNumElements();
2378       // If this is a null-terminated string, use the denser CSTRING encoding.
2379       if (Str->isCString()) {
2380         Code = bitc::CST_CODE_CSTRING;
2381         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2382       } else {
2383         Code = bitc::CST_CODE_STRING;
2384         AbbrevToUse = String8Abbrev;
2385       }
2386       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2387       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2388       for (unsigned i = 0; i != NumElts; ++i) {
2389         unsigned char V = Str->getElementAsInteger(i);
2390         Record.push_back(V);
2391         isCStr7 &= (V & 128) == 0;
2392         if (isCStrChar6)
2393           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2394       }
2395 
2396       if (isCStrChar6)
2397         AbbrevToUse = CString6Abbrev;
2398       else if (isCStr7)
2399         AbbrevToUse = CString7Abbrev;
2400     } else if (const ConstantDataSequential *CDS =
2401                   dyn_cast<ConstantDataSequential>(C)) {
2402       Code = bitc::CST_CODE_DATA;
2403       Type *EltTy = CDS->getType()->getElementType();
2404       if (isa<IntegerType>(EltTy)) {
2405         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2406           Record.push_back(CDS->getElementAsInteger(i));
2407       } else {
2408         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2409           Record.push_back(
2410               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2411       }
2412     } else if (isa<ConstantAggregate>(C)) {
2413       Code = bitc::CST_CODE_AGGREGATE;
2414       for (const Value *Op : C->operands())
2415         Record.push_back(VE.getValueID(Op));
2416       AbbrevToUse = AggregateAbbrev;
2417     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2418       switch (CE->getOpcode()) {
2419       default:
2420         if (Instruction::isCast(CE->getOpcode())) {
2421           Code = bitc::CST_CODE_CE_CAST;
2422           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2423           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2424           Record.push_back(VE.getValueID(C->getOperand(0)));
2425           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2426         } else {
2427           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2428           Code = bitc::CST_CODE_CE_BINOP;
2429           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2430           Record.push_back(VE.getValueID(C->getOperand(0)));
2431           Record.push_back(VE.getValueID(C->getOperand(1)));
2432           uint64_t Flags = getOptimizationFlags(CE);
2433           if (Flags != 0)
2434             Record.push_back(Flags);
2435         }
2436         break;
2437       case Instruction::FNeg: {
2438         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2439         Code = bitc::CST_CODE_CE_UNOP;
2440         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2441         Record.push_back(VE.getValueID(C->getOperand(0)));
2442         uint64_t Flags = getOptimizationFlags(CE);
2443         if (Flags != 0)
2444           Record.push_back(Flags);
2445         break;
2446       }
2447       case Instruction::GetElementPtr: {
2448         Code = bitc::CST_CODE_CE_GEP;
2449         const auto *GO = cast<GEPOperator>(C);
2450         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2451         if (Optional<unsigned> Idx = GO->getInRangeIndex()) {
2452           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2453           Record.push_back((*Idx << 1) | GO->isInBounds());
2454         } else if (GO->isInBounds())
2455           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2456         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2457           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2458           Record.push_back(VE.getValueID(C->getOperand(i)));
2459         }
2460         break;
2461       }
2462       case Instruction::Select:
2463         Code = bitc::CST_CODE_CE_SELECT;
2464         Record.push_back(VE.getValueID(C->getOperand(0)));
2465         Record.push_back(VE.getValueID(C->getOperand(1)));
2466         Record.push_back(VE.getValueID(C->getOperand(2)));
2467         break;
2468       case Instruction::ExtractElement:
2469         Code = bitc::CST_CODE_CE_EXTRACTELT;
2470         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2471         Record.push_back(VE.getValueID(C->getOperand(0)));
2472         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2473         Record.push_back(VE.getValueID(C->getOperand(1)));
2474         break;
2475       case Instruction::InsertElement:
2476         Code = bitc::CST_CODE_CE_INSERTELT;
2477         Record.push_back(VE.getValueID(C->getOperand(0)));
2478         Record.push_back(VE.getValueID(C->getOperand(1)));
2479         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2480         Record.push_back(VE.getValueID(C->getOperand(2)));
2481         break;
2482       case Instruction::ShuffleVector:
2483         // If the return type and argument types are the same, this is a
2484         // standard shufflevector instruction.  If the types are different,
2485         // then the shuffle is widening or truncating the input vectors, and
2486         // the argument type must also be encoded.
2487         if (C->getType() == C->getOperand(0)->getType()) {
2488           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2489         } else {
2490           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2491           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2492         }
2493         Record.push_back(VE.getValueID(C->getOperand(0)));
2494         Record.push_back(VE.getValueID(C->getOperand(1)));
2495         Record.push_back(VE.getValueID(C->getOperand(2)));
2496         break;
2497       case Instruction::ICmp:
2498       case Instruction::FCmp:
2499         Code = bitc::CST_CODE_CE_CMP;
2500         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2501         Record.push_back(VE.getValueID(C->getOperand(0)));
2502         Record.push_back(VE.getValueID(C->getOperand(1)));
2503         Record.push_back(CE->getPredicate());
2504         break;
2505       }
2506     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2507       Code = bitc::CST_CODE_BLOCKADDRESS;
2508       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2509       Record.push_back(VE.getValueID(BA->getFunction()));
2510       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2511     } else {
2512 #ifndef NDEBUG
2513       C->dump();
2514 #endif
2515       llvm_unreachable("Unknown constant!");
2516     }
2517     Stream.EmitRecord(Code, Record, AbbrevToUse);
2518     Record.clear();
2519   }
2520 
2521   Stream.ExitBlock();
2522 }
2523 
2524 void ModuleBitcodeWriter::writeModuleConstants() {
2525   const ValueEnumerator::ValueList &Vals = VE.getValues();
2526 
2527   // Find the first constant to emit, which is the first non-globalvalue value.
2528   // We know globalvalues have been emitted by WriteModuleInfo.
2529   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2530     if (!isa<GlobalValue>(Vals[i].first)) {
2531       writeConstants(i, Vals.size(), true);
2532       return;
2533     }
2534   }
2535 }
2536 
2537 /// pushValueAndType - The file has to encode both the value and type id for
2538 /// many values, because we need to know what type to create for forward
2539 /// references.  However, most operands are not forward references, so this type
2540 /// field is not needed.
2541 ///
2542 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2543 /// instruction ID, then it is a forward reference, and it also includes the
2544 /// type ID.  The value ID that is written is encoded relative to the InstID.
2545 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2546                                            SmallVectorImpl<unsigned> &Vals) {
2547   unsigned ValID = VE.getValueID(V);
2548   // Make encoding relative to the InstID.
2549   Vals.push_back(InstID - ValID);
2550   if (ValID >= InstID) {
2551     Vals.push_back(VE.getTypeID(V->getType()));
2552     return true;
2553   }
2554   return false;
2555 }
2556 
2557 void ModuleBitcodeWriter::writeOperandBundles(ImmutableCallSite CS,
2558                                               unsigned InstID) {
2559   SmallVector<unsigned, 64> Record;
2560   LLVMContext &C = CS.getInstruction()->getContext();
2561 
2562   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2563     const auto &Bundle = CS.getOperandBundleAt(i);
2564     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2565 
2566     for (auto &Input : Bundle.Inputs)
2567       pushValueAndType(Input, InstID, Record);
2568 
2569     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2570     Record.clear();
2571   }
2572 }
2573 
2574 /// pushValue - Like pushValueAndType, but where the type of the value is
2575 /// omitted (perhaps it was already encoded in an earlier operand).
2576 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2577                                     SmallVectorImpl<unsigned> &Vals) {
2578   unsigned ValID = VE.getValueID(V);
2579   Vals.push_back(InstID - ValID);
2580 }
2581 
2582 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2583                                           SmallVectorImpl<uint64_t> &Vals) {
2584   unsigned ValID = VE.getValueID(V);
2585   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2586   emitSignedInt64(Vals, diff);
2587 }
2588 
2589 /// WriteInstruction - Emit an instruction to the specified stream.
2590 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2591                                            unsigned InstID,
2592                                            SmallVectorImpl<unsigned> &Vals) {
2593   unsigned Code = 0;
2594   unsigned AbbrevToUse = 0;
2595   VE.setInstructionID(&I);
2596   switch (I.getOpcode()) {
2597   default:
2598     if (Instruction::isCast(I.getOpcode())) {
2599       Code = bitc::FUNC_CODE_INST_CAST;
2600       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2601         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2602       Vals.push_back(VE.getTypeID(I.getType()));
2603       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2604     } else {
2605       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2606       Code = bitc::FUNC_CODE_INST_BINOP;
2607       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2608         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2609       pushValue(I.getOperand(1), InstID, Vals);
2610       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2611       uint64_t Flags = getOptimizationFlags(&I);
2612       if (Flags != 0) {
2613         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2614           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2615         Vals.push_back(Flags);
2616       }
2617     }
2618     break;
2619   case Instruction::FNeg: {
2620     Code = bitc::FUNC_CODE_INST_UNOP;
2621     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2622       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
2623     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
2624     uint64_t Flags = getOptimizationFlags(&I);
2625     if (Flags != 0) {
2626       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
2627         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
2628       Vals.push_back(Flags);
2629     }
2630     break;
2631   }
2632   case Instruction::GetElementPtr: {
2633     Code = bitc::FUNC_CODE_INST_GEP;
2634     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2635     auto &GEPInst = cast<GetElementPtrInst>(I);
2636     Vals.push_back(GEPInst.isInBounds());
2637     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2638     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2639       pushValueAndType(I.getOperand(i), InstID, Vals);
2640     break;
2641   }
2642   case Instruction::ExtractValue: {
2643     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2644     pushValueAndType(I.getOperand(0), InstID, Vals);
2645     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2646     Vals.append(EVI->idx_begin(), EVI->idx_end());
2647     break;
2648   }
2649   case Instruction::InsertValue: {
2650     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2651     pushValueAndType(I.getOperand(0), InstID, Vals);
2652     pushValueAndType(I.getOperand(1), InstID, Vals);
2653     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2654     Vals.append(IVI->idx_begin(), IVI->idx_end());
2655     break;
2656   }
2657   case Instruction::Select: {
2658     Code = bitc::FUNC_CODE_INST_VSELECT;
2659     pushValueAndType(I.getOperand(1), InstID, Vals);
2660     pushValue(I.getOperand(2), InstID, Vals);
2661     pushValueAndType(I.getOperand(0), InstID, Vals);
2662     uint64_t Flags = getOptimizationFlags(&I);
2663     if (Flags != 0)
2664       Vals.push_back(Flags);
2665     break;
2666   }
2667   case Instruction::ExtractElement:
2668     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2669     pushValueAndType(I.getOperand(0), InstID, Vals);
2670     pushValueAndType(I.getOperand(1), InstID, Vals);
2671     break;
2672   case Instruction::InsertElement:
2673     Code = bitc::FUNC_CODE_INST_INSERTELT;
2674     pushValueAndType(I.getOperand(0), InstID, Vals);
2675     pushValue(I.getOperand(1), InstID, Vals);
2676     pushValueAndType(I.getOperand(2), InstID, Vals);
2677     break;
2678   case Instruction::ShuffleVector:
2679     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2680     pushValueAndType(I.getOperand(0), InstID, Vals);
2681     pushValue(I.getOperand(1), InstID, Vals);
2682     pushValue(I.getOperand(2), InstID, Vals);
2683     break;
2684   case Instruction::ICmp:
2685   case Instruction::FCmp: {
2686     // compare returning Int1Ty or vector of Int1Ty
2687     Code = bitc::FUNC_CODE_INST_CMP2;
2688     pushValueAndType(I.getOperand(0), InstID, Vals);
2689     pushValue(I.getOperand(1), InstID, Vals);
2690     Vals.push_back(cast<CmpInst>(I).getPredicate());
2691     uint64_t Flags = getOptimizationFlags(&I);
2692     if (Flags != 0)
2693       Vals.push_back(Flags);
2694     break;
2695   }
2696 
2697   case Instruction::Ret:
2698     {
2699       Code = bitc::FUNC_CODE_INST_RET;
2700       unsigned NumOperands = I.getNumOperands();
2701       if (NumOperands == 0)
2702         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2703       else if (NumOperands == 1) {
2704         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2705           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2706       } else {
2707         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2708           pushValueAndType(I.getOperand(i), InstID, Vals);
2709       }
2710     }
2711     break;
2712   case Instruction::Br:
2713     {
2714       Code = bitc::FUNC_CODE_INST_BR;
2715       const BranchInst &II = cast<BranchInst>(I);
2716       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2717       if (II.isConditional()) {
2718         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2719         pushValue(II.getCondition(), InstID, Vals);
2720       }
2721     }
2722     break;
2723   case Instruction::Switch:
2724     {
2725       Code = bitc::FUNC_CODE_INST_SWITCH;
2726       const SwitchInst &SI = cast<SwitchInst>(I);
2727       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2728       pushValue(SI.getCondition(), InstID, Vals);
2729       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2730       for (auto Case : SI.cases()) {
2731         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2732         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2733       }
2734     }
2735     break;
2736   case Instruction::IndirectBr:
2737     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2738     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2739     // Encode the address operand as relative, but not the basic blocks.
2740     pushValue(I.getOperand(0), InstID, Vals);
2741     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2742       Vals.push_back(VE.getValueID(I.getOperand(i)));
2743     break;
2744 
2745   case Instruction::Invoke: {
2746     const InvokeInst *II = cast<InvokeInst>(&I);
2747     const Value *Callee = II->getCalledValue();
2748     FunctionType *FTy = II->getFunctionType();
2749 
2750     if (II->hasOperandBundles())
2751       writeOperandBundles(II, InstID);
2752 
2753     Code = bitc::FUNC_CODE_INST_INVOKE;
2754 
2755     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
2756     Vals.push_back(II->getCallingConv() | 1 << 13);
2757     Vals.push_back(VE.getValueID(II->getNormalDest()));
2758     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2759     Vals.push_back(VE.getTypeID(FTy));
2760     pushValueAndType(Callee, InstID, Vals);
2761 
2762     // Emit value #'s for the fixed parameters.
2763     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2764       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2765 
2766     // Emit type/value pairs for varargs params.
2767     if (FTy->isVarArg()) {
2768       for (unsigned i = FTy->getNumParams(), e = II->getNumArgOperands();
2769            i != e; ++i)
2770         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2771     }
2772     break;
2773   }
2774   case Instruction::Resume:
2775     Code = bitc::FUNC_CODE_INST_RESUME;
2776     pushValueAndType(I.getOperand(0), InstID, Vals);
2777     break;
2778   case Instruction::CleanupRet: {
2779     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2780     const auto &CRI = cast<CleanupReturnInst>(I);
2781     pushValue(CRI.getCleanupPad(), InstID, Vals);
2782     if (CRI.hasUnwindDest())
2783       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2784     break;
2785   }
2786   case Instruction::CatchRet: {
2787     Code = bitc::FUNC_CODE_INST_CATCHRET;
2788     const auto &CRI = cast<CatchReturnInst>(I);
2789     pushValue(CRI.getCatchPad(), InstID, Vals);
2790     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2791     break;
2792   }
2793   case Instruction::CleanupPad:
2794   case Instruction::CatchPad: {
2795     const auto &FuncletPad = cast<FuncletPadInst>(I);
2796     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2797                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2798     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2799 
2800     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2801     Vals.push_back(NumArgOperands);
2802     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2803       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2804     break;
2805   }
2806   case Instruction::CatchSwitch: {
2807     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2808     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2809 
2810     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2811 
2812     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2813     Vals.push_back(NumHandlers);
2814     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2815       Vals.push_back(VE.getValueID(CatchPadBB));
2816 
2817     if (CatchSwitch.hasUnwindDest())
2818       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
2819     break;
2820   }
2821   case Instruction::CallBr: {
2822     const CallBrInst *CBI = cast<CallBrInst>(&I);
2823     const Value *Callee = CBI->getCalledValue();
2824     FunctionType *FTy = CBI->getFunctionType();
2825 
2826     if (CBI->hasOperandBundles())
2827       writeOperandBundles(CBI, InstID);
2828 
2829     Code = bitc::FUNC_CODE_INST_CALLBR;
2830 
2831     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
2832 
2833     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
2834                    1 << bitc::CALL_EXPLICIT_TYPE);
2835 
2836     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
2837     Vals.push_back(CBI->getNumIndirectDests());
2838     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
2839       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
2840 
2841     Vals.push_back(VE.getTypeID(FTy));
2842     pushValueAndType(Callee, InstID, Vals);
2843 
2844     // Emit value #'s for the fixed parameters.
2845     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2846       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2847 
2848     // Emit type/value pairs for varargs params.
2849     if (FTy->isVarArg()) {
2850       for (unsigned i = FTy->getNumParams(), e = CBI->getNumArgOperands();
2851            i != e; ++i)
2852         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2853     }
2854     break;
2855   }
2856   case Instruction::Unreachable:
2857     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
2858     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
2859     break;
2860 
2861   case Instruction::PHI: {
2862     const PHINode &PN = cast<PHINode>(I);
2863     Code = bitc::FUNC_CODE_INST_PHI;
2864     // With the newer instruction encoding, forward references could give
2865     // negative valued IDs.  This is most common for PHIs, so we use
2866     // signed VBRs.
2867     SmallVector<uint64_t, 128> Vals64;
2868     Vals64.push_back(VE.getTypeID(PN.getType()));
2869     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
2870       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
2871       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
2872     }
2873     // Emit a Vals64 vector and exit.
2874     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
2875     Vals64.clear();
2876     return;
2877   }
2878 
2879   case Instruction::LandingPad: {
2880     const LandingPadInst &LP = cast<LandingPadInst>(I);
2881     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
2882     Vals.push_back(VE.getTypeID(LP.getType()));
2883     Vals.push_back(LP.isCleanup());
2884     Vals.push_back(LP.getNumClauses());
2885     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
2886       if (LP.isCatch(I))
2887         Vals.push_back(LandingPadInst::Catch);
2888       else
2889         Vals.push_back(LandingPadInst::Filter);
2890       pushValueAndType(LP.getClause(I), InstID, Vals);
2891     }
2892     break;
2893   }
2894 
2895   case Instruction::Alloca: {
2896     Code = bitc::FUNC_CODE_INST_ALLOCA;
2897     const AllocaInst &AI = cast<AllocaInst>(I);
2898     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
2899     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2900     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
2901     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
2902     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
2903            "not enough bits for maximum alignment");
2904     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
2905     AlignRecord |= AI.isUsedWithInAlloca() << 5;
2906     AlignRecord |= 1 << 6;
2907     AlignRecord |= AI.isSwiftError() << 7;
2908     Vals.push_back(AlignRecord);
2909     break;
2910   }
2911 
2912   case Instruction::Load:
2913     if (cast<LoadInst>(I).isAtomic()) {
2914       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
2915       pushValueAndType(I.getOperand(0), InstID, Vals);
2916     } else {
2917       Code = bitc::FUNC_CODE_INST_LOAD;
2918       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
2919         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
2920     }
2921     Vals.push_back(VE.getTypeID(I.getType()));
2922     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
2923     Vals.push_back(cast<LoadInst>(I).isVolatile());
2924     if (cast<LoadInst>(I).isAtomic()) {
2925       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
2926       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
2927     }
2928     break;
2929   case Instruction::Store:
2930     if (cast<StoreInst>(I).isAtomic())
2931       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
2932     else
2933       Code = bitc::FUNC_CODE_INST_STORE;
2934     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
2935     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
2936     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
2937     Vals.push_back(cast<StoreInst>(I).isVolatile());
2938     if (cast<StoreInst>(I).isAtomic()) {
2939       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
2940       Vals.push_back(
2941           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
2942     }
2943     break;
2944   case Instruction::AtomicCmpXchg:
2945     Code = bitc::FUNC_CODE_INST_CMPXCHG;
2946     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
2947     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
2948     pushValue(I.getOperand(2), InstID, Vals);        // newval.
2949     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
2950     Vals.push_back(
2951         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
2952     Vals.push_back(
2953         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
2954     Vals.push_back(
2955         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
2956     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
2957     break;
2958   case Instruction::AtomicRMW:
2959     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
2960     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
2961     pushValue(I.getOperand(1), InstID, Vals);        // val.
2962     Vals.push_back(
2963         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
2964     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
2965     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
2966     Vals.push_back(
2967         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
2968     break;
2969   case Instruction::Fence:
2970     Code = bitc::FUNC_CODE_INST_FENCE;
2971     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
2972     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
2973     break;
2974   case Instruction::Call: {
2975     const CallInst &CI = cast<CallInst>(I);
2976     FunctionType *FTy = CI.getFunctionType();
2977 
2978     if (CI.hasOperandBundles())
2979       writeOperandBundles(&CI, InstID);
2980 
2981     Code = bitc::FUNC_CODE_INST_CALL;
2982 
2983     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
2984 
2985     unsigned Flags = getOptimizationFlags(&I);
2986     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
2987                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
2988                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
2989                    1 << bitc::CALL_EXPLICIT_TYPE |
2990                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
2991                    unsigned(Flags != 0) << bitc::CALL_FMF);
2992     if (Flags != 0)
2993       Vals.push_back(Flags);
2994 
2995     Vals.push_back(VE.getTypeID(FTy));
2996     pushValueAndType(CI.getCalledValue(), InstID, Vals); // Callee
2997 
2998     // Emit value #'s for the fixed parameters.
2999     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3000       // Check for labels (can happen with asm labels).
3001       if (FTy->getParamType(i)->isLabelTy())
3002         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3003       else
3004         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3005     }
3006 
3007     // Emit type/value pairs for varargs params.
3008     if (FTy->isVarArg()) {
3009       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
3010            i != e; ++i)
3011         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3012     }
3013     break;
3014   }
3015   case Instruction::VAArg:
3016     Code = bitc::FUNC_CODE_INST_VAARG;
3017     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3018     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3019     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3020     break;
3021   }
3022 
3023   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3024   Vals.clear();
3025 }
3026 
3027 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3028 /// to allow clients to efficiently find the function body.
3029 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3030   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3031   // Get the offset of the VST we are writing, and backpatch it into
3032   // the VST forward declaration record.
3033   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3034   // The BitcodeStartBit was the stream offset of the identification block.
3035   VSTOffset -= bitcodeStartBit();
3036   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3037   // Note that we add 1 here because the offset is relative to one word
3038   // before the start of the identification block, which was historically
3039   // always the start of the regular bitcode header.
3040   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3041 
3042   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3043 
3044   auto Abbv = std::make_shared<BitCodeAbbrev>();
3045   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3046   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3047   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3048   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3049 
3050   for (const Function &F : M) {
3051     uint64_t Record[2];
3052 
3053     if (F.isDeclaration())
3054       continue;
3055 
3056     Record[0] = VE.getValueID(&F);
3057 
3058     // Save the word offset of the function (from the start of the
3059     // actual bitcode written to the stream).
3060     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3061     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3062     // Note that we add 1 here because the offset is relative to one word
3063     // before the start of the identification block, which was historically
3064     // always the start of the regular bitcode header.
3065     Record[1] = BitcodeIndex / 32 + 1;
3066 
3067     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3068   }
3069 
3070   Stream.ExitBlock();
3071 }
3072 
3073 /// Emit names for arguments, instructions and basic blocks in a function.
3074 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3075     const ValueSymbolTable &VST) {
3076   if (VST.empty())
3077     return;
3078 
3079   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3080 
3081   // FIXME: Set up the abbrev, we know how many values there are!
3082   // FIXME: We know if the type names can use 7-bit ascii.
3083   SmallVector<uint64_t, 64> NameVals;
3084 
3085   for (const ValueName &Name : VST) {
3086     // Figure out the encoding to use for the name.
3087     StringEncoding Bits = getStringEncoding(Name.getKey());
3088 
3089     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3090     NameVals.push_back(VE.getValueID(Name.getValue()));
3091 
3092     // VST_CODE_ENTRY:   [valueid, namechar x N]
3093     // VST_CODE_BBENTRY: [bbid, namechar x N]
3094     unsigned Code;
3095     if (isa<BasicBlock>(Name.getValue())) {
3096       Code = bitc::VST_CODE_BBENTRY;
3097       if (Bits == SE_Char6)
3098         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3099     } else {
3100       Code = bitc::VST_CODE_ENTRY;
3101       if (Bits == SE_Char6)
3102         AbbrevToUse = VST_ENTRY_6_ABBREV;
3103       else if (Bits == SE_Fixed7)
3104         AbbrevToUse = VST_ENTRY_7_ABBREV;
3105     }
3106 
3107     for (const auto P : Name.getKey())
3108       NameVals.push_back((unsigned char)P);
3109 
3110     // Emit the finished record.
3111     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3112     NameVals.clear();
3113   }
3114 
3115   Stream.ExitBlock();
3116 }
3117 
3118 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3119   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3120   unsigned Code;
3121   if (isa<BasicBlock>(Order.V))
3122     Code = bitc::USELIST_CODE_BB;
3123   else
3124     Code = bitc::USELIST_CODE_DEFAULT;
3125 
3126   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3127   Record.push_back(VE.getValueID(Order.V));
3128   Stream.EmitRecord(Code, Record);
3129 }
3130 
3131 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3132   assert(VE.shouldPreserveUseListOrder() &&
3133          "Expected to be preserving use-list order");
3134 
3135   auto hasMore = [&]() {
3136     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3137   };
3138   if (!hasMore())
3139     // Nothing to do.
3140     return;
3141 
3142   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3143   while (hasMore()) {
3144     writeUseList(std::move(VE.UseListOrders.back()));
3145     VE.UseListOrders.pop_back();
3146   }
3147   Stream.ExitBlock();
3148 }
3149 
3150 /// Emit a function body to the module stream.
3151 void ModuleBitcodeWriter::writeFunction(
3152     const Function &F,
3153     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3154   // Save the bitcode index of the start of this function block for recording
3155   // in the VST.
3156   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3157 
3158   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3159   VE.incorporateFunction(F);
3160 
3161   SmallVector<unsigned, 64> Vals;
3162 
3163   // Emit the number of basic blocks, so the reader can create them ahead of
3164   // time.
3165   Vals.push_back(VE.getBasicBlocks().size());
3166   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3167   Vals.clear();
3168 
3169   // If there are function-local constants, emit them now.
3170   unsigned CstStart, CstEnd;
3171   VE.getFunctionConstantRange(CstStart, CstEnd);
3172   writeConstants(CstStart, CstEnd, false);
3173 
3174   // If there is function-local metadata, emit it now.
3175   writeFunctionMetadata(F);
3176 
3177   // Keep a running idea of what the instruction ID is.
3178   unsigned InstID = CstEnd;
3179 
3180   bool NeedsMetadataAttachment = F.hasMetadata();
3181 
3182   DILocation *LastDL = nullptr;
3183   // Finally, emit all the instructions, in order.
3184   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
3185     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
3186          I != E; ++I) {
3187       writeInstruction(*I, InstID, Vals);
3188 
3189       if (!I->getType()->isVoidTy())
3190         ++InstID;
3191 
3192       // If the instruction has metadata, write a metadata attachment later.
3193       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
3194 
3195       // If the instruction has a debug location, emit it.
3196       DILocation *DL = I->getDebugLoc();
3197       if (!DL)
3198         continue;
3199 
3200       if (DL == LastDL) {
3201         // Just repeat the same debug loc as last time.
3202         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3203         continue;
3204       }
3205 
3206       Vals.push_back(DL->getLine());
3207       Vals.push_back(DL->getColumn());
3208       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3209       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3210       Vals.push_back(DL->isImplicitCode());
3211       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3212       Vals.clear();
3213 
3214       LastDL = DL;
3215     }
3216 
3217   // Emit names for all the instructions etc.
3218   if (auto *Symtab = F.getValueSymbolTable())
3219     writeFunctionLevelValueSymbolTable(*Symtab);
3220 
3221   if (NeedsMetadataAttachment)
3222     writeFunctionMetadataAttachment(F);
3223   if (VE.shouldPreserveUseListOrder())
3224     writeUseListBlock(&F);
3225   VE.purgeFunction();
3226   Stream.ExitBlock();
3227 }
3228 
3229 // Emit blockinfo, which defines the standard abbreviations etc.
3230 void ModuleBitcodeWriter::writeBlockInfo() {
3231   // We only want to emit block info records for blocks that have multiple
3232   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3233   // Other blocks can define their abbrevs inline.
3234   Stream.EnterBlockInfoBlock();
3235 
3236   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3237     auto Abbv = std::make_shared<BitCodeAbbrev>();
3238     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3239     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3240     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3241     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3242     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3243         VST_ENTRY_8_ABBREV)
3244       llvm_unreachable("Unexpected abbrev ordering!");
3245   }
3246 
3247   { // 7-bit fixed width VST_CODE_ENTRY strings.
3248     auto Abbv = std::make_shared<BitCodeAbbrev>();
3249     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3250     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3251     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3252     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3253     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3254         VST_ENTRY_7_ABBREV)
3255       llvm_unreachable("Unexpected abbrev ordering!");
3256   }
3257   { // 6-bit char6 VST_CODE_ENTRY strings.
3258     auto Abbv = std::make_shared<BitCodeAbbrev>();
3259     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3260     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3261     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3262     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3263     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3264         VST_ENTRY_6_ABBREV)
3265       llvm_unreachable("Unexpected abbrev ordering!");
3266   }
3267   { // 6-bit char6 VST_CODE_BBENTRY strings.
3268     auto Abbv = std::make_shared<BitCodeAbbrev>();
3269     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3270     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3271     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3272     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3273     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3274         VST_BBENTRY_6_ABBREV)
3275       llvm_unreachable("Unexpected abbrev ordering!");
3276   }
3277 
3278   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3279     auto Abbv = std::make_shared<BitCodeAbbrev>();
3280     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3281     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3282                               VE.computeBitsRequiredForTypeIndicies()));
3283     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3284         CONSTANTS_SETTYPE_ABBREV)
3285       llvm_unreachable("Unexpected abbrev ordering!");
3286   }
3287 
3288   { // INTEGER abbrev for CONSTANTS_BLOCK.
3289     auto Abbv = std::make_shared<BitCodeAbbrev>();
3290     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3291     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3292     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3293         CONSTANTS_INTEGER_ABBREV)
3294       llvm_unreachable("Unexpected abbrev ordering!");
3295   }
3296 
3297   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3298     auto Abbv = std::make_shared<BitCodeAbbrev>();
3299     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3300     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3301     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3302                               VE.computeBitsRequiredForTypeIndicies()));
3303     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3304 
3305     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3306         CONSTANTS_CE_CAST_Abbrev)
3307       llvm_unreachable("Unexpected abbrev ordering!");
3308   }
3309   { // NULL abbrev for CONSTANTS_BLOCK.
3310     auto Abbv = std::make_shared<BitCodeAbbrev>();
3311     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3312     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3313         CONSTANTS_NULL_Abbrev)
3314       llvm_unreachable("Unexpected abbrev ordering!");
3315   }
3316 
3317   // FIXME: This should only use space for first class types!
3318 
3319   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3320     auto Abbv = std::make_shared<BitCodeAbbrev>();
3321     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3322     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3323     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3324                               VE.computeBitsRequiredForTypeIndicies()));
3325     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3326     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3327     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3328         FUNCTION_INST_LOAD_ABBREV)
3329       llvm_unreachable("Unexpected abbrev ordering!");
3330   }
3331   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3332     auto Abbv = std::make_shared<BitCodeAbbrev>();
3333     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3334     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3335     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3336     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3337         FUNCTION_INST_UNOP_ABBREV)
3338       llvm_unreachable("Unexpected abbrev ordering!");
3339   }
3340   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3341     auto Abbv = std::make_shared<BitCodeAbbrev>();
3342     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3343     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3344     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3345     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3346     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3347         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3348       llvm_unreachable("Unexpected abbrev ordering!");
3349   }
3350   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3351     auto Abbv = std::make_shared<BitCodeAbbrev>();
3352     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3353     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3354     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3355     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3356     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3357         FUNCTION_INST_BINOP_ABBREV)
3358       llvm_unreachable("Unexpected abbrev ordering!");
3359   }
3360   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3361     auto Abbv = std::make_shared<BitCodeAbbrev>();
3362     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3363     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3364     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3365     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3366     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3367     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3368         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3369       llvm_unreachable("Unexpected abbrev ordering!");
3370   }
3371   { // INST_CAST abbrev for FUNCTION_BLOCK.
3372     auto Abbv = std::make_shared<BitCodeAbbrev>();
3373     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3374     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3375     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3376                               VE.computeBitsRequiredForTypeIndicies()));
3377     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3378     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3379         FUNCTION_INST_CAST_ABBREV)
3380       llvm_unreachable("Unexpected abbrev ordering!");
3381   }
3382 
3383   { // INST_RET abbrev for FUNCTION_BLOCK.
3384     auto Abbv = std::make_shared<BitCodeAbbrev>();
3385     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3386     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3387         FUNCTION_INST_RET_VOID_ABBREV)
3388       llvm_unreachable("Unexpected abbrev ordering!");
3389   }
3390   { // INST_RET abbrev for FUNCTION_BLOCK.
3391     auto Abbv = std::make_shared<BitCodeAbbrev>();
3392     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3393     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3394     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3395         FUNCTION_INST_RET_VAL_ABBREV)
3396       llvm_unreachable("Unexpected abbrev ordering!");
3397   }
3398   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3399     auto Abbv = std::make_shared<BitCodeAbbrev>();
3400     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3401     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3402         FUNCTION_INST_UNREACHABLE_ABBREV)
3403       llvm_unreachable("Unexpected abbrev ordering!");
3404   }
3405   {
3406     auto Abbv = std::make_shared<BitCodeAbbrev>();
3407     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3408     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3409     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3410                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3411     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3412     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3413     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3414         FUNCTION_INST_GEP_ABBREV)
3415       llvm_unreachable("Unexpected abbrev ordering!");
3416   }
3417 
3418   Stream.ExitBlock();
3419 }
3420 
3421 /// Write the module path strings, currently only used when generating
3422 /// a combined index file.
3423 void IndexBitcodeWriter::writeModStrings() {
3424   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3425 
3426   // TODO: See which abbrev sizes we actually need to emit
3427 
3428   // 8-bit fixed-width MST_ENTRY strings.
3429   auto Abbv = std::make_shared<BitCodeAbbrev>();
3430   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3431   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3432   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3433   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3434   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3435 
3436   // 7-bit fixed width MST_ENTRY strings.
3437   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, 7));
3442   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3443 
3444   // 6-bit char6 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::Char6));
3450   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3451 
3452   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3453   Abbv = std::make_shared<BitCodeAbbrev>();
3454   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3455   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3456   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3457   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3458   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3459   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3460   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3461 
3462   SmallVector<unsigned, 64> Vals;
3463   forEachModule(
3464       [&](const StringMapEntry<std::pair<uint64_t, ModuleHash>> &MPSE) {
3465         StringRef Key = MPSE.getKey();
3466         const auto &Value = MPSE.getValue();
3467         StringEncoding Bits = getStringEncoding(Key);
3468         unsigned AbbrevToUse = Abbrev8Bit;
3469         if (Bits == SE_Char6)
3470           AbbrevToUse = Abbrev6Bit;
3471         else if (Bits == SE_Fixed7)
3472           AbbrevToUse = Abbrev7Bit;
3473 
3474         Vals.push_back(Value.first);
3475         Vals.append(Key.begin(), Key.end());
3476 
3477         // Emit the finished record.
3478         Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3479 
3480         // Emit an optional hash for the module now
3481         const auto &Hash = Value.second;
3482         if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3483           Vals.assign(Hash.begin(), Hash.end());
3484           // Emit the hash record.
3485           Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3486         }
3487 
3488         Vals.clear();
3489       });
3490   Stream.ExitBlock();
3491 }
3492 
3493 /// Write the function type metadata related records that need to appear before
3494 /// a function summary entry (whether per-module or combined).
3495 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
3496                                              FunctionSummary *FS) {
3497   if (!FS->type_tests().empty())
3498     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3499 
3500   SmallVector<uint64_t, 64> Record;
3501 
3502   auto WriteVFuncIdVec = [&](uint64_t Ty,
3503                              ArrayRef<FunctionSummary::VFuncId> VFs) {
3504     if (VFs.empty())
3505       return;
3506     Record.clear();
3507     for (auto &VF : VFs) {
3508       Record.push_back(VF.GUID);
3509       Record.push_back(VF.Offset);
3510     }
3511     Stream.EmitRecord(Ty, Record);
3512   };
3513 
3514   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
3515                   FS->type_test_assume_vcalls());
3516   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
3517                   FS->type_checked_load_vcalls());
3518 
3519   auto WriteConstVCallVec = [&](uint64_t Ty,
3520                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
3521     for (auto &VC : VCs) {
3522       Record.clear();
3523       Record.push_back(VC.VFunc.GUID);
3524       Record.push_back(VC.VFunc.Offset);
3525       Record.insert(Record.end(), VC.Args.begin(), VC.Args.end());
3526       Stream.EmitRecord(Ty, Record);
3527     }
3528   };
3529 
3530   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
3531                      FS->type_test_assume_const_vcalls());
3532   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
3533                      FS->type_checked_load_const_vcalls());
3534 }
3535 
3536 /// Collect type IDs from type tests used by function.
3537 static void
3538 getReferencedTypeIds(FunctionSummary *FS,
3539                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
3540   if (!FS->type_tests().empty())
3541     for (auto &TT : FS->type_tests())
3542       ReferencedTypeIds.insert(TT);
3543 
3544   auto GetReferencedTypesFromVFuncIdVec =
3545       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
3546         for (auto &VF : VFs)
3547           ReferencedTypeIds.insert(VF.GUID);
3548       };
3549 
3550   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
3551   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
3552 
3553   auto GetReferencedTypesFromConstVCallVec =
3554       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
3555         for (auto &VC : VCs)
3556           ReferencedTypeIds.insert(VC.VFunc.GUID);
3557       };
3558 
3559   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
3560   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
3561 }
3562 
3563 static void writeWholeProgramDevirtResolutionByArg(
3564     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
3565     const WholeProgramDevirtResolution::ByArg &ByArg) {
3566   NameVals.push_back(args.size());
3567   NameVals.insert(NameVals.end(), args.begin(), args.end());
3568 
3569   NameVals.push_back(ByArg.TheKind);
3570   NameVals.push_back(ByArg.Info);
3571   NameVals.push_back(ByArg.Byte);
3572   NameVals.push_back(ByArg.Bit);
3573 }
3574 
3575 static void writeWholeProgramDevirtResolution(
3576     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3577     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
3578   NameVals.push_back(Id);
3579 
3580   NameVals.push_back(Wpd.TheKind);
3581   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
3582   NameVals.push_back(Wpd.SingleImplName.size());
3583 
3584   NameVals.push_back(Wpd.ResByArg.size());
3585   for (auto &A : Wpd.ResByArg)
3586     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
3587 }
3588 
3589 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
3590                                      StringTableBuilder &StrtabBuilder,
3591                                      const std::string &Id,
3592                                      const TypeIdSummary &Summary) {
3593   NameVals.push_back(StrtabBuilder.add(Id));
3594   NameVals.push_back(Id.size());
3595 
3596   NameVals.push_back(Summary.TTRes.TheKind);
3597   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
3598   NameVals.push_back(Summary.TTRes.AlignLog2);
3599   NameVals.push_back(Summary.TTRes.SizeM1);
3600   NameVals.push_back(Summary.TTRes.BitMask);
3601   NameVals.push_back(Summary.TTRes.InlineBits);
3602 
3603   for (auto &W : Summary.WPDRes)
3604     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
3605                                       W.second);
3606 }
3607 
3608 // Helper to emit a single function summary record.
3609 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
3610     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3611     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3612     const Function &F) {
3613   NameVals.push_back(ValueID);
3614 
3615   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3616   writeFunctionTypeMetadataRecords(Stream, FS);
3617 
3618   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3619   NameVals.push_back(FS->instCount());
3620   NameVals.push_back(getEncodedFFlags(FS->fflags()));
3621   NameVals.push_back(FS->refs().size());
3622   NameVals.push_back(FS->immutableRefCount());
3623 
3624   for (auto &RI : FS->refs())
3625     NameVals.push_back(VE.getValueID(RI.getValue()));
3626 
3627   bool HasProfileData =
3628       F.hasProfileData() || ForceSummaryEdgesCold != FunctionSummary::FSHT_None;
3629   for (auto &ECI : FS->calls()) {
3630     NameVals.push_back(getValueId(ECI.first));
3631     if (HasProfileData)
3632       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
3633     else if (WriteRelBFToSummary)
3634       NameVals.push_back(ECI.second.RelBlockFreq);
3635   }
3636 
3637   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3638   unsigned Code =
3639       (HasProfileData ? bitc::FS_PERMODULE_PROFILE
3640                       : (WriteRelBFToSummary ? bitc::FS_PERMODULE_RELBF
3641                                              : bitc::FS_PERMODULE));
3642 
3643   // Emit the finished record.
3644   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3645   NameVals.clear();
3646 }
3647 
3648 // Collect the global value references in the given variable's initializer,
3649 // and emit them in a summary record.
3650 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
3651     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3652     unsigned FSModRefsAbbrev) {
3653   auto VI = Index->getValueInfo(V.getGUID());
3654   if (!VI || VI.getSummaryList().empty()) {
3655     // Only declarations should not have a summary (a declaration might however
3656     // have a summary if the def was in module level asm).
3657     assert(V.isDeclaration());
3658     return;
3659   }
3660   auto *Summary = VI.getSummaryList()[0].get();
3661   NameVals.push_back(VE.getValueID(&V));
3662   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
3663   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3664   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
3665 
3666   unsigned SizeBeforeRefs = NameVals.size();
3667   for (auto &RI : VS->refs())
3668     NameVals.push_back(VE.getValueID(RI.getValue()));
3669   // Sort the refs for determinism output, the vector returned by FS->refs() has
3670   // been initialized from a DenseSet.
3671   llvm::sort(NameVals.begin() + SizeBeforeRefs, NameVals.end());
3672 
3673   Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3674                     FSModRefsAbbrev);
3675   NameVals.clear();
3676 }
3677 
3678 // Current version for the summary.
3679 // This is bumped whenever we introduce changes in the way some record are
3680 // interpreted, like flags for instance.
3681 static const uint64_t INDEX_VERSION = 6;
3682 
3683 /// Emit the per-module summary section alongside the rest of
3684 /// the module's bitcode.
3685 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
3686   // By default we compile with ThinLTO if the module has a summary, but the
3687   // client can request full LTO with a module flag.
3688   bool IsThinLTO = true;
3689   if (auto *MD =
3690           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
3691     IsThinLTO = MD->getZExtValue();
3692   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
3693                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
3694                        4);
3695 
3696   Stream.EmitRecord(bitc::FS_VERSION, ArrayRef<uint64_t>{INDEX_VERSION});
3697 
3698   // Write the index flags.
3699   uint64_t Flags = 0;
3700   // Bits 1-3 are set only in the combined index, skip them.
3701   if (Index->enableSplitLTOUnit())
3702     Flags |= 0x8;
3703   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
3704 
3705   if (Index->begin() == Index->end()) {
3706     Stream.ExitBlock();
3707     return;
3708   }
3709 
3710   for (const auto &GVI : valueIds()) {
3711     Stream.EmitRecord(bitc::FS_VALUE_GUID,
3712                       ArrayRef<uint64_t>{GVI.second, GVI.first});
3713   }
3714 
3715   // Abbrev for FS_PERMODULE_PROFILE.
3716   auto Abbv = std::make_shared<BitCodeAbbrev>();
3717   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
3718   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3719   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3720   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3721   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3722   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3723   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // immutablerefcnt
3724   // numrefs x valueid, n x (valueid, hotness)
3725   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3726   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3727   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3728 
3729   // Abbrev for FS_PERMODULE or FS_PERMODULE_RELBF.
3730   Abbv = std::make_shared<BitCodeAbbrev>();
3731   if (WriteRelBFToSummary)
3732     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
3733   else
3734     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
3735   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3736   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3737   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3738   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3739   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3740   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // immutablerefcnt
3741   // numrefs x valueid, n x (valueid [, rel_block_freq])
3742   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3743   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3744   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3745 
3746   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
3747   Abbv = std::make_shared<BitCodeAbbrev>();
3748   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
3749   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3750   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3751   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
3752   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3753   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3754 
3755   // Abbrev for FS_ALIAS.
3756   Abbv = std::make_shared<BitCodeAbbrev>();
3757   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
3758   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3759   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3760   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3761   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3762 
3763   SmallVector<uint64_t, 64> NameVals;
3764   // Iterate over the list of functions instead of the Index to
3765   // ensure the ordering is stable.
3766   for (const Function &F : M) {
3767     // Summary emission does not support anonymous functions, they have to
3768     // renamed using the anonymous function renaming pass.
3769     if (!F.hasName())
3770       report_fatal_error("Unexpected anonymous function when writing summary");
3771 
3772     ValueInfo VI = Index->getValueInfo(F.getGUID());
3773     if (!VI || VI.getSummaryList().empty()) {
3774       // Only declarations should not have a summary (a declaration might
3775       // however have a summary if the def was in module level asm).
3776       assert(F.isDeclaration());
3777       continue;
3778     }
3779     auto *Summary = VI.getSummaryList()[0].get();
3780     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
3781                                         FSCallsAbbrev, FSCallsProfileAbbrev, F);
3782   }
3783 
3784   // Capture references from GlobalVariable initializers, which are outside
3785   // of a function scope.
3786   for (const GlobalVariable &G : M.globals())
3787     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev);
3788 
3789   for (const GlobalAlias &A : M.aliases()) {
3790     auto *Aliasee = A.getBaseObject();
3791     if (!Aliasee->hasName())
3792       // Nameless function don't have an entry in the summary, skip it.
3793       continue;
3794     auto AliasId = VE.getValueID(&A);
3795     auto AliaseeId = VE.getValueID(Aliasee);
3796     NameVals.push_back(AliasId);
3797     auto *Summary = Index->getGlobalValueSummary(A);
3798     AliasSummary *AS = cast<AliasSummary>(Summary);
3799     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
3800     NameVals.push_back(AliaseeId);
3801     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
3802     NameVals.clear();
3803   }
3804 
3805   Stream.ExitBlock();
3806 }
3807 
3808 /// Emit the combined summary section into the combined index file.
3809 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
3810   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
3811   Stream.EmitRecord(bitc::FS_VERSION, ArrayRef<uint64_t>{INDEX_VERSION});
3812 
3813   // Write the index flags.
3814   uint64_t Flags = 0;
3815   if (Index.withGlobalValueDeadStripping())
3816     Flags |= 0x1;
3817   if (Index.skipModuleByDistributedBackend())
3818     Flags |= 0x2;
3819   if (Index.hasSyntheticEntryCounts())
3820     Flags |= 0x4;
3821   if (Index.enableSplitLTOUnit())
3822     Flags |= 0x8;
3823   if (Index.partiallySplitLTOUnits())
3824     Flags |= 0x10;
3825   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
3826 
3827   for (const auto &GVI : valueIds()) {
3828     Stream.EmitRecord(bitc::FS_VALUE_GUID,
3829                       ArrayRef<uint64_t>{GVI.second, GVI.first});
3830   }
3831 
3832   // Abbrev for FS_COMBINED.
3833   auto Abbv = std::make_shared<BitCodeAbbrev>();
3834   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
3835   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3836   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3837   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3838   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3839   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3840   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
3841   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3842   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // immutablerefcnt
3843   // numrefs x valueid, n x (valueid)
3844   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3845   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3846   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3847 
3848   // Abbrev for FS_COMBINED_PROFILE.
3849   Abbv = std::make_shared<BitCodeAbbrev>();
3850   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
3851   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3852   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3853   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3854   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3855   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3856   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
3857   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3858   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // immutablerefcnt
3859   // numrefs x valueid, n x (valueid, hotness)
3860   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3861   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3862   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3863 
3864   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
3865   Abbv = std::make_shared<BitCodeAbbrev>();
3866   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
3867   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3868   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3869   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3870   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
3871   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3872   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3873 
3874   // Abbrev for FS_COMBINED_ALIAS.
3875   Abbv = std::make_shared<BitCodeAbbrev>();
3876   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
3877   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3878   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3879   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3880   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3881   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3882 
3883   // The aliases are emitted as a post-pass, and will point to the value
3884   // id of the aliasee. Save them in a vector for post-processing.
3885   SmallVector<AliasSummary *, 64> Aliases;
3886 
3887   // Save the value id for each summary for alias emission.
3888   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
3889 
3890   SmallVector<uint64_t, 64> NameVals;
3891 
3892   // Set that will be populated during call to writeFunctionTypeMetadataRecords
3893   // with the type ids referenced by this index file.
3894   std::set<GlobalValue::GUID> ReferencedTypeIds;
3895 
3896   // For local linkage, we also emit the original name separately
3897   // immediately after the record.
3898   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
3899     if (!GlobalValue::isLocalLinkage(S.linkage()))
3900       return;
3901     NameVals.push_back(S.getOriginalName());
3902     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
3903     NameVals.clear();
3904   };
3905 
3906   forEachSummary([&](GVInfo I, bool IsAliasee) {
3907     GlobalValueSummary *S = I.second;
3908     assert(S);
3909 
3910     auto ValueId = getValueId(I.first);
3911     assert(ValueId);
3912     SummaryToValueIdMap[S] = *ValueId;
3913 
3914     // If this is invoked for an aliasee, we want to record the above
3915     // mapping, but then not emit a summary entry (if the aliasee is
3916     // to be imported, we will invoke this separately with IsAliasee=false).
3917     if (IsAliasee)
3918       return;
3919 
3920     if (auto *AS = dyn_cast<AliasSummary>(S)) {
3921       // Will process aliases as a post-pass because the reader wants all
3922       // global to be loaded first.
3923       Aliases.push_back(AS);
3924       return;
3925     }
3926 
3927     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
3928       NameVals.push_back(*ValueId);
3929       NameVals.push_back(Index.getModuleId(VS->modulePath()));
3930       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3931       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
3932       for (auto &RI : VS->refs()) {
3933         auto RefValueId = getValueId(RI.getGUID());
3934         if (!RefValueId)
3935           continue;
3936         NameVals.push_back(*RefValueId);
3937       }
3938 
3939       // Emit the finished record.
3940       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
3941                         FSModRefsAbbrev);
3942       NameVals.clear();
3943       MaybeEmitOriginalName(*S);
3944       return;
3945     }
3946 
3947     auto *FS = cast<FunctionSummary>(S);
3948     writeFunctionTypeMetadataRecords(Stream, FS);
3949     getReferencedTypeIds(FS, ReferencedTypeIds);
3950 
3951     NameVals.push_back(*ValueId);
3952     NameVals.push_back(Index.getModuleId(FS->modulePath()));
3953     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3954     NameVals.push_back(FS->instCount());
3955     NameVals.push_back(getEncodedFFlags(FS->fflags()));
3956     NameVals.push_back(FS->entryCount());
3957 
3958     // Fill in below
3959     NameVals.push_back(0); // numrefs
3960     NameVals.push_back(0); // immutablerefcnt
3961 
3962     unsigned Count = 0, ImmutableRefCnt = 0;
3963     for (auto &RI : FS->refs()) {
3964       auto RefValueId = getValueId(RI.getGUID());
3965       if (!RefValueId)
3966         continue;
3967       NameVals.push_back(*RefValueId);
3968       if (RI.isReadOnly())
3969         ImmutableRefCnt++;
3970       Count++;
3971     }
3972     NameVals[6] = Count;
3973     NameVals[7] = ImmutableRefCnt;
3974 
3975     bool HasProfileData = false;
3976     for (auto &EI : FS->calls()) {
3977       HasProfileData |=
3978           EI.second.getHotness() != CalleeInfo::HotnessType::Unknown;
3979       if (HasProfileData)
3980         break;
3981     }
3982 
3983     for (auto &EI : FS->calls()) {
3984       // If this GUID doesn't have a value id, it doesn't have a function
3985       // summary and we don't need to record any calls to it.
3986       GlobalValue::GUID GUID = EI.first.getGUID();
3987       auto CallValueId = getValueId(GUID);
3988       if (!CallValueId) {
3989         // For SamplePGO, the indirect call targets for local functions will
3990         // have its original name annotated in profile. We try to find the
3991         // corresponding PGOFuncName as the GUID.
3992         GUID = Index.getGUIDFromOriginalID(GUID);
3993         if (GUID == 0)
3994           continue;
3995         CallValueId = getValueId(GUID);
3996         if (!CallValueId)
3997           continue;
3998         // The mapping from OriginalId to GUID may return a GUID
3999         // that corresponds to a static variable. Filter it out here.
4000         // This can happen when
4001         // 1) There is a call to a library function which does not have
4002         // a CallValidId;
4003         // 2) There is a static variable with the  OriginalGUID identical
4004         // to the GUID of the library function in 1);
4005         // When this happens, the logic for SamplePGO kicks in and
4006         // the static variable in 2) will be found, which needs to be
4007         // filtered out.
4008         auto *GVSum = Index.getGlobalValueSummary(GUID, false);
4009         if (GVSum &&
4010             GVSum->getSummaryKind() == GlobalValueSummary::GlobalVarKind)
4011           continue;
4012       }
4013       NameVals.push_back(*CallValueId);
4014       if (HasProfileData)
4015         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
4016     }
4017 
4018     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
4019     unsigned Code =
4020         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
4021 
4022     // Emit the finished record.
4023     Stream.EmitRecord(Code, NameVals, FSAbbrev);
4024     NameVals.clear();
4025     MaybeEmitOriginalName(*S);
4026   });
4027 
4028   for (auto *AS : Aliases) {
4029     auto AliasValueId = SummaryToValueIdMap[AS];
4030     assert(AliasValueId);
4031     NameVals.push_back(AliasValueId);
4032     NameVals.push_back(Index.getModuleId(AS->modulePath()));
4033     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4034     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4035     assert(AliaseeValueId);
4036     NameVals.push_back(AliaseeValueId);
4037 
4038     // Emit the finished record.
4039     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4040     NameVals.clear();
4041     MaybeEmitOriginalName(*AS);
4042 
4043     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4044       getReferencedTypeIds(FS, ReferencedTypeIds);
4045   }
4046 
4047   if (!Index.cfiFunctionDefs().empty()) {
4048     for (auto &S : Index.cfiFunctionDefs()) {
4049       NameVals.push_back(StrtabBuilder.add(S));
4050       NameVals.push_back(S.size());
4051     }
4052     Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4053     NameVals.clear();
4054   }
4055 
4056   if (!Index.cfiFunctionDecls().empty()) {
4057     for (auto &S : Index.cfiFunctionDecls()) {
4058       NameVals.push_back(StrtabBuilder.add(S));
4059       NameVals.push_back(S.size());
4060     }
4061     Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4062     NameVals.clear();
4063   }
4064 
4065   // Walk the GUIDs that were referenced, and write the
4066   // corresponding type id records.
4067   for (auto &T : ReferencedTypeIds) {
4068     auto TidIter = Index.typeIds().equal_range(T);
4069     for (auto It = TidIter.first; It != TidIter.second; ++It) {
4070       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, It->second.first,
4071                                It->second.second);
4072       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4073       NameVals.clear();
4074     }
4075   }
4076 
4077   Stream.ExitBlock();
4078 }
4079 
4080 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4081 /// current llvm version, and a record for the epoch number.
4082 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4083   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4084 
4085   // Write the "user readable" string identifying the bitcode producer
4086   auto Abbv = std::make_shared<BitCodeAbbrev>();
4087   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4088   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4089   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4090   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4091   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4092                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4093 
4094   // Write the epoch version
4095   Abbv = std::make_shared<BitCodeAbbrev>();
4096   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4097   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4098   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4099   SmallVector<unsigned, 1> Vals = {bitc::BITCODE_CURRENT_EPOCH};
4100   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4101   Stream.ExitBlock();
4102 }
4103 
4104 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
4105   // Emit the module's hash.
4106   // MODULE_CODE_HASH: [5*i32]
4107   if (GenerateHash) {
4108     uint32_t Vals[5];
4109     Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
4110                                     Buffer.size() - BlockStartPos));
4111     StringRef Hash = Hasher.result();
4112     for (int Pos = 0; Pos < 20; Pos += 4) {
4113       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4114     }
4115 
4116     // Emit the finished record.
4117     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4118 
4119     if (ModHash)
4120       // Save the written hash value.
4121       llvm::copy(Vals, std::begin(*ModHash));
4122   }
4123 }
4124 
4125 void ModuleBitcodeWriter::write() {
4126   writeIdentificationBlock(Stream);
4127 
4128   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4129   size_t BlockStartPos = Buffer.size();
4130 
4131   writeModuleVersion();
4132 
4133   // Emit blockinfo, which defines the standard abbreviations etc.
4134   writeBlockInfo();
4135 
4136   // Emit information describing all of the types in the module.
4137   writeTypeTable();
4138 
4139   // Emit information about attribute groups.
4140   writeAttributeGroupTable();
4141 
4142   // Emit information about parameter attributes.
4143   writeAttributeTable();
4144 
4145   writeComdats();
4146 
4147   // Emit top-level description of module, including target triple, inline asm,
4148   // descriptors for global variables, and function prototype info.
4149   writeModuleInfo();
4150 
4151   // Emit constants.
4152   writeModuleConstants();
4153 
4154   // Emit metadata kind names.
4155   writeModuleMetadataKinds();
4156 
4157   // Emit metadata.
4158   writeModuleMetadata();
4159 
4160   // Emit module-level use-lists.
4161   if (VE.shouldPreserveUseListOrder())
4162     writeUseListBlock(nullptr);
4163 
4164   writeOperandBundleTags();
4165   writeSyncScopeNames();
4166 
4167   // Emit function bodies.
4168   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4169   for (Module::const_iterator F = M.begin(), E = M.end(); F != E; ++F)
4170     if (!F->isDeclaration())
4171       writeFunction(*F, FunctionToBitcodeIndex);
4172 
4173   // Need to write after the above call to WriteFunction which populates
4174   // the summary information in the index.
4175   if (Index)
4176     writePerModuleGlobalValueSummary();
4177 
4178   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4179 
4180   writeModuleHash(BlockStartPos);
4181 
4182   Stream.ExitBlock();
4183 }
4184 
4185 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4186                                uint32_t &Position) {
4187   support::endian::write32le(&Buffer[Position], Value);
4188   Position += 4;
4189 }
4190 
4191 /// If generating a bc file on darwin, we have to emit a
4192 /// header and trailer to make it compatible with the system archiver.  To do
4193 /// this we emit the following header, and then emit a trailer that pads the
4194 /// file out to be a multiple of 16 bytes.
4195 ///
4196 /// struct bc_header {
4197 ///   uint32_t Magic;         // 0x0B17C0DE
4198 ///   uint32_t Version;       // Version, currently always 0.
4199 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4200 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4201 ///   uint32_t CPUType;       // CPU specifier.
4202 ///   ... potentially more later ...
4203 /// };
4204 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4205                                          const Triple &TT) {
4206   unsigned CPUType = ~0U;
4207 
4208   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4209   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4210   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4211   // specific constants here because they are implicitly part of the Darwin ABI.
4212   enum {
4213     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4214     DARWIN_CPU_TYPE_X86        = 7,
4215     DARWIN_CPU_TYPE_ARM        = 12,
4216     DARWIN_CPU_TYPE_POWERPC    = 18
4217   };
4218 
4219   Triple::ArchType Arch = TT.getArch();
4220   if (Arch == Triple::x86_64)
4221     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4222   else if (Arch == Triple::x86)
4223     CPUType = DARWIN_CPU_TYPE_X86;
4224   else if (Arch == Triple::ppc)
4225     CPUType = DARWIN_CPU_TYPE_POWERPC;
4226   else if (Arch == Triple::ppc64)
4227     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
4228   else if (Arch == Triple::arm || Arch == Triple::thumb)
4229     CPUType = DARWIN_CPU_TYPE_ARM;
4230 
4231   // Traditional Bitcode starts after header.
4232   assert(Buffer.size() >= BWH_HeaderSize &&
4233          "Expected header size to be reserved");
4234   unsigned BCOffset = BWH_HeaderSize;
4235   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
4236 
4237   // Write the magic and version.
4238   unsigned Position = 0;
4239   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
4240   writeInt32ToBuffer(0, Buffer, Position); // Version.
4241   writeInt32ToBuffer(BCOffset, Buffer, Position);
4242   writeInt32ToBuffer(BCSize, Buffer, Position);
4243   writeInt32ToBuffer(CPUType, Buffer, Position);
4244 
4245   // If the file is not a multiple of 16 bytes, insert dummy padding.
4246   while (Buffer.size() & 15)
4247     Buffer.push_back(0);
4248 }
4249 
4250 /// Helper to write the header common to all bitcode files.
4251 static void writeBitcodeHeader(BitstreamWriter &Stream) {
4252   // Emit the file header.
4253   Stream.Emit((unsigned)'B', 8);
4254   Stream.Emit((unsigned)'C', 8);
4255   Stream.Emit(0x0, 4);
4256   Stream.Emit(0xC, 4);
4257   Stream.Emit(0xE, 4);
4258   Stream.Emit(0xD, 4);
4259 }
4260 
4261 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer)
4262     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer)) {
4263   writeBitcodeHeader(*Stream);
4264 }
4265 
4266 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
4267 
4268 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
4269   Stream->EnterSubblock(Block, 3);
4270 
4271   auto Abbv = std::make_shared<BitCodeAbbrev>();
4272   Abbv->Add(BitCodeAbbrevOp(Record));
4273   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
4274   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
4275 
4276   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
4277 
4278   Stream->ExitBlock();
4279 }
4280 
4281 void BitcodeWriter::writeSymtab() {
4282   assert(!WroteStrtab && !WroteSymtab);
4283 
4284   // If any module has module-level inline asm, we will require a registered asm
4285   // parser for the target so that we can create an accurate symbol table for
4286   // the module.
4287   for (Module *M : Mods) {
4288     if (M->getModuleInlineAsm().empty())
4289       continue;
4290 
4291     std::string Err;
4292     const Triple TT(M->getTargetTriple());
4293     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
4294     if (!T || !T->hasMCAsmParser())
4295       return;
4296   }
4297 
4298   WroteSymtab = true;
4299   SmallVector<char, 0> Symtab;
4300   // The irsymtab::build function may be unable to create a symbol table if the
4301   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
4302   // table is not required for correctness, but we still want to be able to
4303   // write malformed modules to bitcode files, so swallow the error.
4304   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
4305     consumeError(std::move(E));
4306     return;
4307   }
4308 
4309   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
4310             {Symtab.data(), Symtab.size()});
4311 }
4312 
4313 void BitcodeWriter::writeStrtab() {
4314   assert(!WroteStrtab);
4315 
4316   std::vector<char> Strtab;
4317   StrtabBuilder.finalizeInOrder();
4318   Strtab.resize(StrtabBuilder.getSize());
4319   StrtabBuilder.write((uint8_t *)Strtab.data());
4320 
4321   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
4322             {Strtab.data(), Strtab.size()});
4323 
4324   WroteStrtab = true;
4325 }
4326 
4327 void BitcodeWriter::copyStrtab(StringRef Strtab) {
4328   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
4329   WroteStrtab = true;
4330 }
4331 
4332 void BitcodeWriter::writeModule(const Module &M,
4333                                 bool ShouldPreserveUseListOrder,
4334                                 const ModuleSummaryIndex *Index,
4335                                 bool GenerateHash, ModuleHash *ModHash) {
4336   assert(!WroteStrtab);
4337 
4338   // The Mods vector is used by irsymtab::build, which requires non-const
4339   // Modules in case it needs to materialize metadata. But the bitcode writer
4340   // requires that the module is materialized, so we can cast to non-const here,
4341   // after checking that it is in fact materialized.
4342   assert(M.isMaterialized());
4343   Mods.push_back(const_cast<Module *>(&M));
4344 
4345   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
4346                                    ShouldPreserveUseListOrder, Index,
4347                                    GenerateHash, ModHash);
4348   ModuleWriter.write();
4349 }
4350 
4351 void BitcodeWriter::writeIndex(
4352     const ModuleSummaryIndex *Index,
4353     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4354   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
4355                                  ModuleToSummariesForIndex);
4356   IndexWriter.write();
4357 }
4358 
4359 /// Write the specified module to the specified output stream.
4360 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
4361                               bool ShouldPreserveUseListOrder,
4362                               const ModuleSummaryIndex *Index,
4363                               bool GenerateHash, ModuleHash *ModHash) {
4364   SmallVector<char, 0> Buffer;
4365   Buffer.reserve(256*1024);
4366 
4367   // If this is darwin or another generic macho target, reserve space for the
4368   // header.
4369   Triple TT(M.getTargetTriple());
4370   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4371     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
4372 
4373   BitcodeWriter Writer(Buffer);
4374   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
4375                      ModHash);
4376   Writer.writeSymtab();
4377   Writer.writeStrtab();
4378 
4379   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4380     emitDarwinBCHeaderAndTrailer(Buffer, TT);
4381 
4382   // Write the generated bitstream to "Out".
4383   Out.write((char*)&Buffer.front(), Buffer.size());
4384 }
4385 
4386 void IndexBitcodeWriter::write() {
4387   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4388 
4389   writeModuleVersion();
4390 
4391   // Write the module paths in the combined index.
4392   writeModStrings();
4393 
4394   // Write the summary combined index records.
4395   writeCombinedGlobalValueSummary();
4396 
4397   Stream.ExitBlock();
4398 }
4399 
4400 // Write the specified module summary index to the given raw output stream,
4401 // where it will be written in a new bitcode block. This is used when
4402 // writing the combined index file for ThinLTO. When writing a subset of the
4403 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
4404 void llvm::WriteIndexToFile(
4405     const ModuleSummaryIndex &Index, raw_ostream &Out,
4406     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4407   SmallVector<char, 0> Buffer;
4408   Buffer.reserve(256 * 1024);
4409 
4410   BitcodeWriter Writer(Buffer);
4411   Writer.writeIndex(&Index, ModuleToSummariesForIndex);
4412   Writer.writeStrtab();
4413 
4414   Out.write((char *)&Buffer.front(), Buffer.size());
4415 }
4416 
4417 namespace {
4418 
4419 /// Class to manage the bitcode writing for a thin link bitcode file.
4420 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
4421   /// ModHash is for use in ThinLTO incremental build, generated while writing
4422   /// the module bitcode file.
4423   const ModuleHash *ModHash;
4424 
4425 public:
4426   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
4427                         BitstreamWriter &Stream,
4428                         const ModuleSummaryIndex &Index,
4429                         const ModuleHash &ModHash)
4430       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
4431                                 /*ShouldPreserveUseListOrder=*/false, &Index),
4432         ModHash(&ModHash) {}
4433 
4434   void write();
4435 
4436 private:
4437   void writeSimplifiedModuleInfo();
4438 };
4439 
4440 } // end anonymous namespace
4441 
4442 // This function writes a simpilified module info for thin link bitcode file.
4443 // It only contains the source file name along with the name(the offset and
4444 // size in strtab) and linkage for global values. For the global value info
4445 // entry, in order to keep linkage at offset 5, there are three zeros used
4446 // as padding.
4447 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
4448   SmallVector<unsigned, 64> Vals;
4449   // Emit the module's source file name.
4450   {
4451     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
4452     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
4453     if (Bits == SE_Char6)
4454       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
4455     else if (Bits == SE_Fixed7)
4456       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
4457 
4458     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
4459     auto Abbv = std::make_shared<BitCodeAbbrev>();
4460     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
4461     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4462     Abbv->Add(AbbrevOpToUse);
4463     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4464 
4465     for (const auto P : M.getSourceFileName())
4466       Vals.push_back((unsigned char)P);
4467 
4468     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
4469     Vals.clear();
4470   }
4471 
4472   // Emit the global variable information.
4473   for (const GlobalVariable &GV : M.globals()) {
4474     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
4475     Vals.push_back(StrtabBuilder.add(GV.getName()));
4476     Vals.push_back(GV.getName().size());
4477     Vals.push_back(0);
4478     Vals.push_back(0);
4479     Vals.push_back(0);
4480     Vals.push_back(getEncodedLinkage(GV));
4481 
4482     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
4483     Vals.clear();
4484   }
4485 
4486   // Emit the function proto information.
4487   for (const Function &F : M) {
4488     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
4489     Vals.push_back(StrtabBuilder.add(F.getName()));
4490     Vals.push_back(F.getName().size());
4491     Vals.push_back(0);
4492     Vals.push_back(0);
4493     Vals.push_back(0);
4494     Vals.push_back(getEncodedLinkage(F));
4495 
4496     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
4497     Vals.clear();
4498   }
4499 
4500   // Emit the alias information.
4501   for (const GlobalAlias &A : M.aliases()) {
4502     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
4503     Vals.push_back(StrtabBuilder.add(A.getName()));
4504     Vals.push_back(A.getName().size());
4505     Vals.push_back(0);
4506     Vals.push_back(0);
4507     Vals.push_back(0);
4508     Vals.push_back(getEncodedLinkage(A));
4509 
4510     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
4511     Vals.clear();
4512   }
4513 
4514   // Emit the ifunc information.
4515   for (const GlobalIFunc &I : M.ifuncs()) {
4516     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
4517     Vals.push_back(StrtabBuilder.add(I.getName()));
4518     Vals.push_back(I.getName().size());
4519     Vals.push_back(0);
4520     Vals.push_back(0);
4521     Vals.push_back(0);
4522     Vals.push_back(getEncodedLinkage(I));
4523 
4524     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
4525     Vals.clear();
4526   }
4527 }
4528 
4529 void ThinLinkBitcodeWriter::write() {
4530   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4531 
4532   writeModuleVersion();
4533 
4534   writeSimplifiedModuleInfo();
4535 
4536   writePerModuleGlobalValueSummary();
4537 
4538   // Write module hash.
4539   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
4540 
4541   Stream.ExitBlock();
4542 }
4543 
4544 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
4545                                          const ModuleSummaryIndex &Index,
4546                                          const ModuleHash &ModHash) {
4547   assert(!WroteStrtab);
4548 
4549   // The Mods vector is used by irsymtab::build, which requires non-const
4550   // Modules in case it needs to materialize metadata. But the bitcode writer
4551   // requires that the module is materialized, so we can cast to non-const here,
4552   // after checking that it is in fact materialized.
4553   assert(M.isMaterialized());
4554   Mods.push_back(const_cast<Module *>(&M));
4555 
4556   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
4557                                        ModHash);
4558   ThinLinkWriter.write();
4559 }
4560 
4561 // Write the specified thin link bitcode file to the given raw output stream,
4562 // where it will be written in a new bitcode block. This is used when
4563 // writing the per-module index file for ThinLTO.
4564 void llvm::WriteThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
4565                                       const ModuleSummaryIndex &Index,
4566                                       const ModuleHash &ModHash) {
4567   SmallVector<char, 0> Buffer;
4568   Buffer.reserve(256 * 1024);
4569 
4570   BitcodeWriter Writer(Buffer);
4571   Writer.writeThinLinkBitcode(M, Index, ModHash);
4572   Writer.writeSymtab();
4573   Writer.writeStrtab();
4574 
4575   Out.write((char *)&Buffer.front(), Buffer.size());
4576 }
4577