xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision d383df32c0d5bcdc8c160ecdd7174399aa3c5395)
1 //===- Bitcode/Writer/BitcodeWriter.cpp - Bitcode Writer ------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // Bitcode writer implementation.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "llvm/Bitcode/BitcodeWriter.h"
14 #include "ValueEnumerator.h"
15 #include "llvm/ADT/APFloat.h"
16 #include "llvm/ADT/APInt.h"
17 #include "llvm/ADT/ArrayRef.h"
18 #include "llvm/ADT/DenseMap.h"
19 #include "llvm/ADT/None.h"
20 #include "llvm/ADT/Optional.h"
21 #include "llvm/ADT/STLExtras.h"
22 #include "llvm/ADT/SmallString.h"
23 #include "llvm/ADT/SmallVector.h"
24 #include "llvm/ADT/StringMap.h"
25 #include "llvm/ADT/StringRef.h"
26 #include "llvm/ADT/Triple.h"
27 #include "llvm/Bitcode/BitcodeCommon.h"
28 #include "llvm/Bitcode/BitcodeReader.h"
29 #include "llvm/Bitcode/LLVMBitCodes.h"
30 #include "llvm/Bitstream/BitCodes.h"
31 #include "llvm/Bitstream/BitstreamWriter.h"
32 #include "llvm/Config/llvm-config.h"
33 #include "llvm/IR/Attributes.h"
34 #include "llvm/IR/BasicBlock.h"
35 #include "llvm/IR/Comdat.h"
36 #include "llvm/IR/Constant.h"
37 #include "llvm/IR/Constants.h"
38 #include "llvm/IR/DebugInfoMetadata.h"
39 #include "llvm/IR/DebugLoc.h"
40 #include "llvm/IR/DerivedTypes.h"
41 #include "llvm/IR/Function.h"
42 #include "llvm/IR/GlobalAlias.h"
43 #include "llvm/IR/GlobalIFunc.h"
44 #include "llvm/IR/GlobalObject.h"
45 #include "llvm/IR/GlobalValue.h"
46 #include "llvm/IR/GlobalVariable.h"
47 #include "llvm/IR/InlineAsm.h"
48 #include "llvm/IR/InstrTypes.h"
49 #include "llvm/IR/Instruction.h"
50 #include "llvm/IR/Instructions.h"
51 #include "llvm/IR/LLVMContext.h"
52 #include "llvm/IR/Metadata.h"
53 #include "llvm/IR/Module.h"
54 #include "llvm/IR/ModuleSummaryIndex.h"
55 #include "llvm/IR/Operator.h"
56 #include "llvm/IR/Type.h"
57 #include "llvm/IR/UseListOrder.h"
58 #include "llvm/IR/Value.h"
59 #include "llvm/IR/ValueSymbolTable.h"
60 #include "llvm/MC/StringTableBuilder.h"
61 #include "llvm/Object/IRSymtab.h"
62 #include "llvm/Support/AtomicOrdering.h"
63 #include "llvm/Support/Casting.h"
64 #include "llvm/Support/CommandLine.h"
65 #include "llvm/Support/Endian.h"
66 #include "llvm/Support/Error.h"
67 #include "llvm/Support/ErrorHandling.h"
68 #include "llvm/Support/MathExtras.h"
69 #include "llvm/Support/SHA1.h"
70 #include "llvm/Support/TargetRegistry.h"
71 #include "llvm/Support/raw_ostream.h"
72 #include <algorithm>
73 #include <cassert>
74 #include <cstddef>
75 #include <cstdint>
76 #include <iterator>
77 #include <map>
78 #include <memory>
79 #include <string>
80 #include <utility>
81 #include <vector>
82 
83 using namespace llvm;
84 
85 static cl::opt<unsigned>
86     IndexThreshold("bitcode-mdindex-threshold", cl::Hidden, cl::init(25),
87                    cl::desc("Number of metadatas above which we emit an index "
88                             "to enable lazy-loading"));
89 static cl::opt<uint32_t> FlushThreshold(
90     "bitcode-flush-threshold", cl::Hidden, cl::init(512),
91     cl::desc("The threshold (unit M) for flushing LLVM bitcode."));
92 
93 static cl::opt<bool> WriteRelBFToSummary(
94     "write-relbf-to-summary", cl::Hidden, cl::init(false),
95     cl::desc("Write relative block frequency to function summary "));
96 
97 extern FunctionSummary::ForceSummaryHotnessType ForceSummaryEdgesCold;
98 
99 namespace {
100 
101 /// These are manifest constants used by the bitcode writer. They do not need to
102 /// be kept in sync with the reader, but need to be consistent within this file.
103 enum {
104   // VALUE_SYMTAB_BLOCK abbrev id's.
105   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
106   VST_ENTRY_7_ABBREV,
107   VST_ENTRY_6_ABBREV,
108   VST_BBENTRY_6_ABBREV,
109 
110   // CONSTANTS_BLOCK abbrev id's.
111   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
112   CONSTANTS_INTEGER_ABBREV,
113   CONSTANTS_CE_CAST_Abbrev,
114   CONSTANTS_NULL_Abbrev,
115 
116   // FUNCTION_BLOCK abbrev id's.
117   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
118   FUNCTION_INST_UNOP_ABBREV,
119   FUNCTION_INST_UNOP_FLAGS_ABBREV,
120   FUNCTION_INST_BINOP_ABBREV,
121   FUNCTION_INST_BINOP_FLAGS_ABBREV,
122   FUNCTION_INST_CAST_ABBREV,
123   FUNCTION_INST_RET_VOID_ABBREV,
124   FUNCTION_INST_RET_VAL_ABBREV,
125   FUNCTION_INST_UNREACHABLE_ABBREV,
126   FUNCTION_INST_GEP_ABBREV,
127 };
128 
129 /// Abstract class to manage the bitcode writing, subclassed for each bitcode
130 /// file type.
131 class BitcodeWriterBase {
132 protected:
133   /// The stream created and owned by the client.
134   BitstreamWriter &Stream;
135 
136   StringTableBuilder &StrtabBuilder;
137 
138 public:
139   /// Constructs a BitcodeWriterBase object that writes to the provided
140   /// \p Stream.
141   BitcodeWriterBase(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder)
142       : Stream(Stream), StrtabBuilder(StrtabBuilder) {}
143 
144 protected:
145   void writeModuleVersion();
146 };
147 
148 void BitcodeWriterBase::writeModuleVersion() {
149   // VERSION: [version#]
150   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, ArrayRef<uint64_t>{2});
151 }
152 
153 /// Base class to manage the module bitcode writing, currently subclassed for
154 /// ModuleBitcodeWriter and ThinLinkBitcodeWriter.
155 class ModuleBitcodeWriterBase : public BitcodeWriterBase {
156 protected:
157   /// The Module to write to bitcode.
158   const Module &M;
159 
160   /// Enumerates ids for all values in the module.
161   ValueEnumerator VE;
162 
163   /// Optional per-module index to write for ThinLTO.
164   const ModuleSummaryIndex *Index;
165 
166   /// Map that holds the correspondence between GUIDs in the summary index,
167   /// that came from indirect call profiles, and a value id generated by this
168   /// class to use in the VST and summary block records.
169   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
170 
171   /// Tracks the last value id recorded in the GUIDToValueMap.
172   unsigned GlobalValueId;
173 
174   /// Saves the offset of the VSTOffset record that must eventually be
175   /// backpatched with the offset of the actual VST.
176   uint64_t VSTOffsetPlaceholder = 0;
177 
178 public:
179   /// Constructs a ModuleBitcodeWriterBase object for the given Module,
180   /// writing to the provided \p Buffer.
181   ModuleBitcodeWriterBase(const Module &M, StringTableBuilder &StrtabBuilder,
182                           BitstreamWriter &Stream,
183                           bool ShouldPreserveUseListOrder,
184                           const ModuleSummaryIndex *Index)
185       : BitcodeWriterBase(Stream, StrtabBuilder), M(M),
186         VE(M, ShouldPreserveUseListOrder), Index(Index) {
187     // Assign ValueIds to any callee values in the index that came from
188     // indirect call profiles and were recorded as a GUID not a Value*
189     // (which would have been assigned an ID by the ValueEnumerator).
190     // The starting ValueId is just after the number of values in the
191     // ValueEnumerator, so that they can be emitted in the VST.
192     GlobalValueId = VE.getValues().size();
193     if (!Index)
194       return;
195     for (const auto &GUIDSummaryLists : *Index)
196       // Examine all summaries for this GUID.
197       for (auto &Summary : GUIDSummaryLists.second.SummaryList)
198         if (auto FS = dyn_cast<FunctionSummary>(Summary.get()))
199           // For each call in the function summary, see if the call
200           // is to a GUID (which means it is for an indirect call,
201           // otherwise we would have a Value for it). If so, synthesize
202           // a value id.
203           for (auto &CallEdge : FS->calls())
204             if (!CallEdge.first.haveGVs() || !CallEdge.first.getValue())
205               assignValueId(CallEdge.first.getGUID());
206   }
207 
208 protected:
209   void writePerModuleGlobalValueSummary();
210 
211 private:
212   void writePerModuleFunctionSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
213                                            GlobalValueSummary *Summary,
214                                            unsigned ValueID,
215                                            unsigned FSCallsAbbrev,
216                                            unsigned FSCallsProfileAbbrev,
217                                            const Function &F);
218   void writeModuleLevelReferences(const GlobalVariable &V,
219                                   SmallVector<uint64_t, 64> &NameVals,
220                                   unsigned FSModRefsAbbrev,
221                                   unsigned FSModVTableRefsAbbrev);
222 
223   void assignValueId(GlobalValue::GUID ValGUID) {
224     GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
225   }
226 
227   unsigned getValueId(GlobalValue::GUID ValGUID) {
228     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
229     // Expect that any GUID value had a value Id assigned by an
230     // earlier call to assignValueId.
231     assert(VMI != GUIDToValueIdMap.end() &&
232            "GUID does not have assigned value Id");
233     return VMI->second;
234   }
235 
236   // Helper to get the valueId for the type of value recorded in VI.
237   unsigned getValueId(ValueInfo VI) {
238     if (!VI.haveGVs() || !VI.getValue())
239       return getValueId(VI.getGUID());
240     return VE.getValueID(VI.getValue());
241   }
242 
243   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
244 };
245 
246 /// Class to manage the bitcode writing for a module.
247 class ModuleBitcodeWriter : public ModuleBitcodeWriterBase {
248   /// Pointer to the buffer allocated by caller for bitcode writing.
249   const SmallVectorImpl<char> &Buffer;
250 
251   /// True if a module hash record should be written.
252   bool GenerateHash;
253 
254   /// If non-null, when GenerateHash is true, the resulting hash is written
255   /// into ModHash.
256   ModuleHash *ModHash;
257 
258   SHA1 Hasher;
259 
260   /// The start bit of the identification block.
261   uint64_t BitcodeStartBit;
262 
263 public:
264   /// Constructs a ModuleBitcodeWriter object for the given Module,
265   /// writing to the provided \p Buffer.
266   ModuleBitcodeWriter(const Module &M, SmallVectorImpl<char> &Buffer,
267                       StringTableBuilder &StrtabBuilder,
268                       BitstreamWriter &Stream, bool ShouldPreserveUseListOrder,
269                       const ModuleSummaryIndex *Index, bool GenerateHash,
270                       ModuleHash *ModHash = nullptr)
271       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
272                                 ShouldPreserveUseListOrder, Index),
273         Buffer(Buffer), GenerateHash(GenerateHash), ModHash(ModHash),
274         BitcodeStartBit(Stream.GetCurrentBitNo()) {}
275 
276   /// Emit the current module to the bitstream.
277   void write();
278 
279 private:
280   uint64_t bitcodeStartBit() { return BitcodeStartBit; }
281 
282   size_t addToStrtab(StringRef Str);
283 
284   void writeAttributeGroupTable();
285   void writeAttributeTable();
286   void writeTypeTable();
287   void writeComdats();
288   void writeValueSymbolTableForwardDecl();
289   void writeModuleInfo();
290   void writeValueAsMetadata(const ValueAsMetadata *MD,
291                             SmallVectorImpl<uint64_t> &Record);
292   void writeMDTuple(const MDTuple *N, SmallVectorImpl<uint64_t> &Record,
293                     unsigned Abbrev);
294   unsigned createDILocationAbbrev();
295   void writeDILocation(const DILocation *N, SmallVectorImpl<uint64_t> &Record,
296                        unsigned &Abbrev);
297   unsigned createGenericDINodeAbbrev();
298   void writeGenericDINode(const GenericDINode *N,
299                           SmallVectorImpl<uint64_t> &Record, unsigned &Abbrev);
300   void writeDISubrange(const DISubrange *N, SmallVectorImpl<uint64_t> &Record,
301                        unsigned Abbrev);
302   void writeDIGenericSubrange(const DIGenericSubrange *N,
303                               SmallVectorImpl<uint64_t> &Record,
304                               unsigned Abbrev);
305   void writeDIEnumerator(const DIEnumerator *N,
306                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
307   void writeDIBasicType(const DIBasicType *N, SmallVectorImpl<uint64_t> &Record,
308                         unsigned Abbrev);
309   void writeDIStringType(const DIStringType *N,
310                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
311   void writeDIDerivedType(const DIDerivedType *N,
312                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
313   void writeDICompositeType(const DICompositeType *N,
314                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
315   void writeDISubroutineType(const DISubroutineType *N,
316                              SmallVectorImpl<uint64_t> &Record,
317                              unsigned Abbrev);
318   void writeDIFile(const DIFile *N, SmallVectorImpl<uint64_t> &Record,
319                    unsigned Abbrev);
320   void writeDICompileUnit(const DICompileUnit *N,
321                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
322   void writeDISubprogram(const DISubprogram *N,
323                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
324   void writeDILexicalBlock(const DILexicalBlock *N,
325                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
326   void writeDILexicalBlockFile(const DILexicalBlockFile *N,
327                                SmallVectorImpl<uint64_t> &Record,
328                                unsigned Abbrev);
329   void writeDICommonBlock(const DICommonBlock *N,
330                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
331   void writeDINamespace(const DINamespace *N, SmallVectorImpl<uint64_t> &Record,
332                         unsigned Abbrev);
333   void writeDIMacro(const DIMacro *N, SmallVectorImpl<uint64_t> &Record,
334                     unsigned Abbrev);
335   void writeDIMacroFile(const DIMacroFile *N, SmallVectorImpl<uint64_t> &Record,
336                         unsigned Abbrev);
337   void writeDIArgList(const DIArgList *N, SmallVectorImpl<uint64_t> &Record,
338                       unsigned Abbrev);
339   void writeDIModule(const DIModule *N, SmallVectorImpl<uint64_t> &Record,
340                      unsigned Abbrev);
341   void writeDITemplateTypeParameter(const DITemplateTypeParameter *N,
342                                     SmallVectorImpl<uint64_t> &Record,
343                                     unsigned Abbrev);
344   void writeDITemplateValueParameter(const DITemplateValueParameter *N,
345                                      SmallVectorImpl<uint64_t> &Record,
346                                      unsigned Abbrev);
347   void writeDIGlobalVariable(const DIGlobalVariable *N,
348                              SmallVectorImpl<uint64_t> &Record,
349                              unsigned Abbrev);
350   void writeDILocalVariable(const DILocalVariable *N,
351                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
352   void writeDILabel(const DILabel *N,
353                     SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
354   void writeDIExpression(const DIExpression *N,
355                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
356   void writeDIGlobalVariableExpression(const DIGlobalVariableExpression *N,
357                                        SmallVectorImpl<uint64_t> &Record,
358                                        unsigned Abbrev);
359   void writeDIObjCProperty(const DIObjCProperty *N,
360                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
361   void writeDIImportedEntity(const DIImportedEntity *N,
362                              SmallVectorImpl<uint64_t> &Record,
363                              unsigned Abbrev);
364   unsigned createNamedMetadataAbbrev();
365   void writeNamedMetadata(SmallVectorImpl<uint64_t> &Record);
366   unsigned createMetadataStringsAbbrev();
367   void writeMetadataStrings(ArrayRef<const Metadata *> Strings,
368                             SmallVectorImpl<uint64_t> &Record);
369   void writeMetadataRecords(ArrayRef<const Metadata *> MDs,
370                             SmallVectorImpl<uint64_t> &Record,
371                             std::vector<unsigned> *MDAbbrevs = nullptr,
372                             std::vector<uint64_t> *IndexPos = nullptr);
373   void writeModuleMetadata();
374   void writeFunctionMetadata(const Function &F);
375   void writeFunctionMetadataAttachment(const Function &F);
376   void pushGlobalMetadataAttachment(SmallVectorImpl<uint64_t> &Record,
377                                     const GlobalObject &GO);
378   void writeModuleMetadataKinds();
379   void writeOperandBundleTags();
380   void writeSyncScopeNames();
381   void writeConstants(unsigned FirstVal, unsigned LastVal, bool isGlobal);
382   void writeModuleConstants();
383   bool pushValueAndType(const Value *V, unsigned InstID,
384                         SmallVectorImpl<unsigned> &Vals);
385   void writeOperandBundles(const CallBase &CB, unsigned InstID);
386   void pushValue(const Value *V, unsigned InstID,
387                  SmallVectorImpl<unsigned> &Vals);
388   void pushValueSigned(const Value *V, unsigned InstID,
389                        SmallVectorImpl<uint64_t> &Vals);
390   void writeInstruction(const Instruction &I, unsigned InstID,
391                         SmallVectorImpl<unsigned> &Vals);
392   void writeFunctionLevelValueSymbolTable(const ValueSymbolTable &VST);
393   void writeGlobalValueSymbolTable(
394       DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
395   void writeUseList(UseListOrder &&Order);
396   void writeUseListBlock(const Function *F);
397   void
398   writeFunction(const Function &F,
399                 DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
400   void writeBlockInfo();
401   void writeModuleHash(size_t BlockStartPos);
402 
403   unsigned getEncodedSyncScopeID(SyncScope::ID SSID) {
404     return unsigned(SSID);
405   }
406 
407   unsigned getEncodedAlign(MaybeAlign Alignment) { return encode(Alignment); }
408 };
409 
410 /// Class to manage the bitcode writing for a combined index.
411 class IndexBitcodeWriter : public BitcodeWriterBase {
412   /// The combined index to write to bitcode.
413   const ModuleSummaryIndex &Index;
414 
415   /// When writing a subset of the index for distributed backends, client
416   /// provides a map of modules to the corresponding GUIDs/summaries to write.
417   const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex;
418 
419   /// Map that holds the correspondence between the GUID used in the combined
420   /// index and a value id generated by this class to use in references.
421   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
422 
423   /// Tracks the last value id recorded in the GUIDToValueMap.
424   unsigned GlobalValueId = 0;
425 
426 public:
427   /// Constructs a IndexBitcodeWriter object for the given combined index,
428   /// writing to the provided \p Buffer. When writing a subset of the index
429   /// for a distributed backend, provide a \p ModuleToSummariesForIndex map.
430   IndexBitcodeWriter(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder,
431                      const ModuleSummaryIndex &Index,
432                      const std::map<std::string, GVSummaryMapTy>
433                          *ModuleToSummariesForIndex = nullptr)
434       : BitcodeWriterBase(Stream, StrtabBuilder), Index(Index),
435         ModuleToSummariesForIndex(ModuleToSummariesForIndex) {
436     // Assign unique value ids to all summaries to be written, for use
437     // in writing out the call graph edges. Save the mapping from GUID
438     // to the new global value id to use when writing those edges, which
439     // are currently saved in the index in terms of GUID.
440     forEachSummary([&](GVInfo I, bool) {
441       GUIDToValueIdMap[I.first] = ++GlobalValueId;
442     });
443   }
444 
445   /// The below iterator returns the GUID and associated summary.
446   using GVInfo = std::pair<GlobalValue::GUID, GlobalValueSummary *>;
447 
448   /// Calls the callback for each value GUID and summary to be written to
449   /// bitcode. This hides the details of whether they are being pulled from the
450   /// entire index or just those in a provided ModuleToSummariesForIndex map.
451   template<typename Functor>
452   void forEachSummary(Functor Callback) {
453     if (ModuleToSummariesForIndex) {
454       for (auto &M : *ModuleToSummariesForIndex)
455         for (auto &Summary : M.second) {
456           Callback(Summary, false);
457           // Ensure aliasee is handled, e.g. for assigning a valueId,
458           // even if we are not importing the aliasee directly (the
459           // imported alias will contain a copy of aliasee).
460           if (auto *AS = dyn_cast<AliasSummary>(Summary.getSecond()))
461             Callback({AS->getAliaseeGUID(), &AS->getAliasee()}, true);
462         }
463     } else {
464       for (auto &Summaries : Index)
465         for (auto &Summary : Summaries.second.SummaryList)
466           Callback({Summaries.first, Summary.get()}, false);
467     }
468   }
469 
470   /// Calls the callback for each entry in the modulePaths StringMap that
471   /// should be written to the module path string table. This hides the details
472   /// of whether they are being pulled from the entire index or just those in a
473   /// provided ModuleToSummariesForIndex map.
474   template <typename Functor> void forEachModule(Functor Callback) {
475     if (ModuleToSummariesForIndex) {
476       for (const auto &M : *ModuleToSummariesForIndex) {
477         const auto &MPI = Index.modulePaths().find(M.first);
478         if (MPI == Index.modulePaths().end()) {
479           // This should only happen if the bitcode file was empty, in which
480           // case we shouldn't be importing (the ModuleToSummariesForIndex
481           // would only include the module we are writing and index for).
482           assert(ModuleToSummariesForIndex->size() == 1);
483           continue;
484         }
485         Callback(*MPI);
486       }
487     } else {
488       for (const auto &MPSE : Index.modulePaths())
489         Callback(MPSE);
490     }
491   }
492 
493   /// Main entry point for writing a combined index to bitcode.
494   void write();
495 
496 private:
497   void writeModStrings();
498   void writeCombinedGlobalValueSummary();
499 
500   Optional<unsigned> getValueId(GlobalValue::GUID ValGUID) {
501     auto VMI = GUIDToValueIdMap.find(ValGUID);
502     if (VMI == GUIDToValueIdMap.end())
503       return None;
504     return VMI->second;
505   }
506 
507   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
508 };
509 
510 } // end anonymous namespace
511 
512 static unsigned getEncodedCastOpcode(unsigned Opcode) {
513   switch (Opcode) {
514   default: llvm_unreachable("Unknown cast instruction!");
515   case Instruction::Trunc   : return bitc::CAST_TRUNC;
516   case Instruction::ZExt    : return bitc::CAST_ZEXT;
517   case Instruction::SExt    : return bitc::CAST_SEXT;
518   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
519   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
520   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
521   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
522   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
523   case Instruction::FPExt   : return bitc::CAST_FPEXT;
524   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
525   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
526   case Instruction::BitCast : return bitc::CAST_BITCAST;
527   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
528   }
529 }
530 
531 static unsigned getEncodedUnaryOpcode(unsigned Opcode) {
532   switch (Opcode) {
533   default: llvm_unreachable("Unknown binary instruction!");
534   case Instruction::FNeg: return bitc::UNOP_FNEG;
535   }
536 }
537 
538 static unsigned getEncodedBinaryOpcode(unsigned Opcode) {
539   switch (Opcode) {
540   default: llvm_unreachable("Unknown binary instruction!");
541   case Instruction::Add:
542   case Instruction::FAdd: return bitc::BINOP_ADD;
543   case Instruction::Sub:
544   case Instruction::FSub: return bitc::BINOP_SUB;
545   case Instruction::Mul:
546   case Instruction::FMul: return bitc::BINOP_MUL;
547   case Instruction::UDiv: return bitc::BINOP_UDIV;
548   case Instruction::FDiv:
549   case Instruction::SDiv: return bitc::BINOP_SDIV;
550   case Instruction::URem: return bitc::BINOP_UREM;
551   case Instruction::FRem:
552   case Instruction::SRem: return bitc::BINOP_SREM;
553   case Instruction::Shl:  return bitc::BINOP_SHL;
554   case Instruction::LShr: return bitc::BINOP_LSHR;
555   case Instruction::AShr: return bitc::BINOP_ASHR;
556   case Instruction::And:  return bitc::BINOP_AND;
557   case Instruction::Or:   return bitc::BINOP_OR;
558   case Instruction::Xor:  return bitc::BINOP_XOR;
559   }
560 }
561 
562 static unsigned getEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
563   switch (Op) {
564   default: llvm_unreachable("Unknown RMW operation!");
565   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
566   case AtomicRMWInst::Add: return bitc::RMW_ADD;
567   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
568   case AtomicRMWInst::And: return bitc::RMW_AND;
569   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
570   case AtomicRMWInst::Or: return bitc::RMW_OR;
571   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
572   case AtomicRMWInst::Max: return bitc::RMW_MAX;
573   case AtomicRMWInst::Min: return bitc::RMW_MIN;
574   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
575   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
576   case AtomicRMWInst::FAdd: return bitc::RMW_FADD;
577   case AtomicRMWInst::FSub: return bitc::RMW_FSUB;
578   }
579 }
580 
581 static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
582   switch (Ordering) {
583   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
584   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
585   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
586   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
587   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
588   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
589   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
590   }
591   llvm_unreachable("Invalid ordering");
592 }
593 
594 static void writeStringRecord(BitstreamWriter &Stream, unsigned Code,
595                               StringRef Str, unsigned AbbrevToUse) {
596   SmallVector<unsigned, 64> Vals;
597 
598   // Code: [strchar x N]
599   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
600     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
601       AbbrevToUse = 0;
602     Vals.push_back(Str[i]);
603   }
604 
605   // Emit the finished record.
606   Stream.EmitRecord(Code, Vals, AbbrevToUse);
607 }
608 
609 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
610   switch (Kind) {
611   case Attribute::Alignment:
612     return bitc::ATTR_KIND_ALIGNMENT;
613   case Attribute::AllocSize:
614     return bitc::ATTR_KIND_ALLOC_SIZE;
615   case Attribute::AlwaysInline:
616     return bitc::ATTR_KIND_ALWAYS_INLINE;
617   case Attribute::ArgMemOnly:
618     return bitc::ATTR_KIND_ARGMEMONLY;
619   case Attribute::Builtin:
620     return bitc::ATTR_KIND_BUILTIN;
621   case Attribute::ByVal:
622     return bitc::ATTR_KIND_BY_VAL;
623   case Attribute::Convergent:
624     return bitc::ATTR_KIND_CONVERGENT;
625   case Attribute::InAlloca:
626     return bitc::ATTR_KIND_IN_ALLOCA;
627   case Attribute::Cold:
628     return bitc::ATTR_KIND_COLD;
629   case Attribute::DisableSanitizerInstrumentation:
630     return bitc::ATTR_KIND_DISABLE_SANITIZER_INSTRUMENTATION;
631   case Attribute::Hot:
632     return bitc::ATTR_KIND_HOT;
633   case Attribute::ElementType:
634     return bitc::ATTR_KIND_ELEMENTTYPE;
635   case Attribute::InaccessibleMemOnly:
636     return bitc::ATTR_KIND_INACCESSIBLEMEM_ONLY;
637   case Attribute::InaccessibleMemOrArgMemOnly:
638     return bitc::ATTR_KIND_INACCESSIBLEMEM_OR_ARGMEMONLY;
639   case Attribute::InlineHint:
640     return bitc::ATTR_KIND_INLINE_HINT;
641   case Attribute::InReg:
642     return bitc::ATTR_KIND_IN_REG;
643   case Attribute::JumpTable:
644     return bitc::ATTR_KIND_JUMP_TABLE;
645   case Attribute::MinSize:
646     return bitc::ATTR_KIND_MIN_SIZE;
647   case Attribute::Naked:
648     return bitc::ATTR_KIND_NAKED;
649   case Attribute::Nest:
650     return bitc::ATTR_KIND_NEST;
651   case Attribute::NoAlias:
652     return bitc::ATTR_KIND_NO_ALIAS;
653   case Attribute::NoBuiltin:
654     return bitc::ATTR_KIND_NO_BUILTIN;
655   case Attribute::NoCallback:
656     return bitc::ATTR_KIND_NO_CALLBACK;
657   case Attribute::NoCapture:
658     return bitc::ATTR_KIND_NO_CAPTURE;
659   case Attribute::NoDuplicate:
660     return bitc::ATTR_KIND_NO_DUPLICATE;
661   case Attribute::NoFree:
662     return bitc::ATTR_KIND_NOFREE;
663   case Attribute::NoImplicitFloat:
664     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
665   case Attribute::NoInline:
666     return bitc::ATTR_KIND_NO_INLINE;
667   case Attribute::NoRecurse:
668     return bitc::ATTR_KIND_NO_RECURSE;
669   case Attribute::NoMerge:
670     return bitc::ATTR_KIND_NO_MERGE;
671   case Attribute::NonLazyBind:
672     return bitc::ATTR_KIND_NON_LAZY_BIND;
673   case Attribute::NonNull:
674     return bitc::ATTR_KIND_NON_NULL;
675   case Attribute::Dereferenceable:
676     return bitc::ATTR_KIND_DEREFERENCEABLE;
677   case Attribute::DereferenceableOrNull:
678     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
679   case Attribute::NoRedZone:
680     return bitc::ATTR_KIND_NO_RED_ZONE;
681   case Attribute::NoReturn:
682     return bitc::ATTR_KIND_NO_RETURN;
683   case Attribute::NoSync:
684     return bitc::ATTR_KIND_NOSYNC;
685   case Attribute::NoCfCheck:
686     return bitc::ATTR_KIND_NOCF_CHECK;
687   case Attribute::NoProfile:
688     return bitc::ATTR_KIND_NO_PROFILE;
689   case Attribute::NoUnwind:
690     return bitc::ATTR_KIND_NO_UNWIND;
691   case Attribute::NoSanitizeCoverage:
692     return bitc::ATTR_KIND_NO_SANITIZE_COVERAGE;
693   case Attribute::NullPointerIsValid:
694     return bitc::ATTR_KIND_NULL_POINTER_IS_VALID;
695   case Attribute::OptForFuzzing:
696     return bitc::ATTR_KIND_OPT_FOR_FUZZING;
697   case Attribute::OptimizeForSize:
698     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
699   case Attribute::OptimizeNone:
700     return bitc::ATTR_KIND_OPTIMIZE_NONE;
701   case Attribute::ReadNone:
702     return bitc::ATTR_KIND_READ_NONE;
703   case Attribute::ReadOnly:
704     return bitc::ATTR_KIND_READ_ONLY;
705   case Attribute::Returned:
706     return bitc::ATTR_KIND_RETURNED;
707   case Attribute::ReturnsTwice:
708     return bitc::ATTR_KIND_RETURNS_TWICE;
709   case Attribute::SExt:
710     return bitc::ATTR_KIND_S_EXT;
711   case Attribute::Speculatable:
712     return bitc::ATTR_KIND_SPECULATABLE;
713   case Attribute::StackAlignment:
714     return bitc::ATTR_KIND_STACK_ALIGNMENT;
715   case Attribute::StackProtect:
716     return bitc::ATTR_KIND_STACK_PROTECT;
717   case Attribute::StackProtectReq:
718     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
719   case Attribute::StackProtectStrong:
720     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
721   case Attribute::SafeStack:
722     return bitc::ATTR_KIND_SAFESTACK;
723   case Attribute::ShadowCallStack:
724     return bitc::ATTR_KIND_SHADOWCALLSTACK;
725   case Attribute::StrictFP:
726     return bitc::ATTR_KIND_STRICT_FP;
727   case Attribute::StructRet:
728     return bitc::ATTR_KIND_STRUCT_RET;
729   case Attribute::SanitizeAddress:
730     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
731   case Attribute::SanitizeHWAddress:
732     return bitc::ATTR_KIND_SANITIZE_HWADDRESS;
733   case Attribute::SanitizeThread:
734     return bitc::ATTR_KIND_SANITIZE_THREAD;
735   case Attribute::SanitizeMemory:
736     return bitc::ATTR_KIND_SANITIZE_MEMORY;
737   case Attribute::SpeculativeLoadHardening:
738     return bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING;
739   case Attribute::SwiftError:
740     return bitc::ATTR_KIND_SWIFT_ERROR;
741   case Attribute::SwiftSelf:
742     return bitc::ATTR_KIND_SWIFT_SELF;
743   case Attribute::SwiftAsync:
744     return bitc::ATTR_KIND_SWIFT_ASYNC;
745   case Attribute::UWTable:
746     return bitc::ATTR_KIND_UW_TABLE;
747   case Attribute::VScaleRange:
748     return bitc::ATTR_KIND_VSCALE_RANGE;
749   case Attribute::WillReturn:
750     return bitc::ATTR_KIND_WILLRETURN;
751   case Attribute::WriteOnly:
752     return bitc::ATTR_KIND_WRITEONLY;
753   case Attribute::ZExt:
754     return bitc::ATTR_KIND_Z_EXT;
755   case Attribute::ImmArg:
756     return bitc::ATTR_KIND_IMMARG;
757   case Attribute::SanitizeMemTag:
758     return bitc::ATTR_KIND_SANITIZE_MEMTAG;
759   case Attribute::Preallocated:
760     return bitc::ATTR_KIND_PREALLOCATED;
761   case Attribute::NoUndef:
762     return bitc::ATTR_KIND_NOUNDEF;
763   case Attribute::ByRef:
764     return bitc::ATTR_KIND_BYREF;
765   case Attribute::MustProgress:
766     return bitc::ATTR_KIND_MUSTPROGRESS;
767   case Attribute::EndAttrKinds:
768     llvm_unreachable("Can not encode end-attribute kinds marker.");
769   case Attribute::None:
770     llvm_unreachable("Can not encode none-attribute.");
771   case Attribute::EmptyKey:
772   case Attribute::TombstoneKey:
773     llvm_unreachable("Trying to encode EmptyKey/TombstoneKey");
774   }
775 
776   llvm_unreachable("Trying to encode unknown attribute");
777 }
778 
779 void ModuleBitcodeWriter::writeAttributeGroupTable() {
780   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
781       VE.getAttributeGroups();
782   if (AttrGrps.empty()) return;
783 
784   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
785 
786   SmallVector<uint64_t, 64> Record;
787   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
788     unsigned AttrListIndex = Pair.first;
789     AttributeSet AS = Pair.second;
790     Record.push_back(VE.getAttributeGroupID(Pair));
791     Record.push_back(AttrListIndex);
792 
793     for (Attribute Attr : AS) {
794       if (Attr.isEnumAttribute()) {
795         Record.push_back(0);
796         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
797       } else if (Attr.isIntAttribute()) {
798         Record.push_back(1);
799         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
800         Record.push_back(Attr.getValueAsInt());
801       } else if (Attr.isStringAttribute()) {
802         StringRef Kind = Attr.getKindAsString();
803         StringRef Val = Attr.getValueAsString();
804 
805         Record.push_back(Val.empty() ? 3 : 4);
806         Record.append(Kind.begin(), Kind.end());
807         Record.push_back(0);
808         if (!Val.empty()) {
809           Record.append(Val.begin(), Val.end());
810           Record.push_back(0);
811         }
812       } else {
813         assert(Attr.isTypeAttribute());
814         Type *Ty = Attr.getValueAsType();
815         Record.push_back(Ty ? 6 : 5);
816         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
817         if (Ty)
818           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
819       }
820     }
821 
822     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
823     Record.clear();
824   }
825 
826   Stream.ExitBlock();
827 }
828 
829 void ModuleBitcodeWriter::writeAttributeTable() {
830   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
831   if (Attrs.empty()) return;
832 
833   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
834 
835   SmallVector<uint64_t, 64> Record;
836   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
837     AttributeList AL = Attrs[i];
838     for (unsigned i = AL.index_begin(), e = AL.index_end(); i != e; ++i) {
839       AttributeSet AS = AL.getAttributes(i);
840       if (AS.hasAttributes())
841         Record.push_back(VE.getAttributeGroupID({i, AS}));
842     }
843 
844     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
845     Record.clear();
846   }
847 
848   Stream.ExitBlock();
849 }
850 
851 /// WriteTypeTable - Write out the type table for a module.
852 void ModuleBitcodeWriter::writeTypeTable() {
853   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
854 
855   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
856   SmallVector<uint64_t, 64> TypeVals;
857 
858   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
859 
860   // Abbrev for TYPE_CODE_POINTER.
861   auto Abbv = std::make_shared<BitCodeAbbrev>();
862   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
863   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
864   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
865   unsigned PtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
866 
867   // Abbrev for TYPE_CODE_OPAQUE_POINTER.
868   Abbv = std::make_shared<BitCodeAbbrev>();
869   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_OPAQUE_POINTER));
870   Abbv->Add(BitCodeAbbrevOp(0)); // Addrspace = 0
871   unsigned OpaquePtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
872 
873   // Abbrev for TYPE_CODE_FUNCTION.
874   Abbv = std::make_shared<BitCodeAbbrev>();
875   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
876   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
877   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
878   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
879   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
880 
881   // Abbrev for TYPE_CODE_STRUCT_ANON.
882   Abbv = std::make_shared<BitCodeAbbrev>();
883   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
884   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
885   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
886   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
887   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
888 
889   // Abbrev for TYPE_CODE_STRUCT_NAME.
890   Abbv = std::make_shared<BitCodeAbbrev>();
891   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
892   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
893   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
894   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
895 
896   // Abbrev for TYPE_CODE_STRUCT_NAMED.
897   Abbv = std::make_shared<BitCodeAbbrev>();
898   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
899   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
900   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
901   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
902   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
903 
904   // Abbrev for TYPE_CODE_ARRAY.
905   Abbv = std::make_shared<BitCodeAbbrev>();
906   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
907   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
908   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
909   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
910 
911   // Emit an entry count so the reader can reserve space.
912   TypeVals.push_back(TypeList.size());
913   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
914   TypeVals.clear();
915 
916   // Loop over all of the types, emitting each in turn.
917   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
918     Type *T = TypeList[i];
919     int AbbrevToUse = 0;
920     unsigned Code = 0;
921 
922     switch (T->getTypeID()) {
923     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
924     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
925     case Type::BFloatTyID:    Code = bitc::TYPE_CODE_BFLOAT;    break;
926     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
927     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
928     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
929     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
930     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
931     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
932     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
933     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
934     case Type::X86_AMXTyID:   Code = bitc::TYPE_CODE_X86_AMX;   break;
935     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
936     case Type::IntegerTyID:
937       // INTEGER: [width]
938       Code = bitc::TYPE_CODE_INTEGER;
939       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
940       break;
941     case Type::PointerTyID: {
942       PointerType *PTy = cast<PointerType>(T);
943       unsigned AddressSpace = PTy->getAddressSpace();
944       if (PTy->isOpaque()) {
945         // OPAQUE_POINTER: [address space]
946         Code = bitc::TYPE_CODE_OPAQUE_POINTER;
947         TypeVals.push_back(AddressSpace);
948         if (AddressSpace == 0)
949           AbbrevToUse = OpaquePtrAbbrev;
950       } else {
951         // POINTER: [pointee type, address space]
952         Code = bitc::TYPE_CODE_POINTER;
953         TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
954         TypeVals.push_back(AddressSpace);
955         if (AddressSpace == 0)
956           AbbrevToUse = PtrAbbrev;
957       }
958       break;
959     }
960     case Type::FunctionTyID: {
961       FunctionType *FT = cast<FunctionType>(T);
962       // FUNCTION: [isvararg, retty, paramty x N]
963       Code = bitc::TYPE_CODE_FUNCTION;
964       TypeVals.push_back(FT->isVarArg());
965       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
966       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
967         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
968       AbbrevToUse = FunctionAbbrev;
969       break;
970     }
971     case Type::StructTyID: {
972       StructType *ST = cast<StructType>(T);
973       // STRUCT: [ispacked, eltty x N]
974       TypeVals.push_back(ST->isPacked());
975       // Output all of the element types.
976       for (StructType::element_iterator I = ST->element_begin(),
977            E = ST->element_end(); I != E; ++I)
978         TypeVals.push_back(VE.getTypeID(*I));
979 
980       if (ST->isLiteral()) {
981         Code = bitc::TYPE_CODE_STRUCT_ANON;
982         AbbrevToUse = StructAnonAbbrev;
983       } else {
984         if (ST->isOpaque()) {
985           Code = bitc::TYPE_CODE_OPAQUE;
986         } else {
987           Code = bitc::TYPE_CODE_STRUCT_NAMED;
988           AbbrevToUse = StructNamedAbbrev;
989         }
990 
991         // Emit the name if it is present.
992         if (!ST->getName().empty())
993           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
994                             StructNameAbbrev);
995       }
996       break;
997     }
998     case Type::ArrayTyID: {
999       ArrayType *AT = cast<ArrayType>(T);
1000       // ARRAY: [numelts, eltty]
1001       Code = bitc::TYPE_CODE_ARRAY;
1002       TypeVals.push_back(AT->getNumElements());
1003       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
1004       AbbrevToUse = ArrayAbbrev;
1005       break;
1006     }
1007     case Type::FixedVectorTyID:
1008     case Type::ScalableVectorTyID: {
1009       VectorType *VT = cast<VectorType>(T);
1010       // VECTOR [numelts, eltty] or
1011       //        [numelts, eltty, scalable]
1012       Code = bitc::TYPE_CODE_VECTOR;
1013       TypeVals.push_back(VT->getElementCount().getKnownMinValue());
1014       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
1015       if (isa<ScalableVectorType>(VT))
1016         TypeVals.push_back(true);
1017       break;
1018     }
1019     }
1020 
1021     // Emit the finished record.
1022     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
1023     TypeVals.clear();
1024   }
1025 
1026   Stream.ExitBlock();
1027 }
1028 
1029 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
1030   switch (Linkage) {
1031   case GlobalValue::ExternalLinkage:
1032     return 0;
1033   case GlobalValue::WeakAnyLinkage:
1034     return 16;
1035   case GlobalValue::AppendingLinkage:
1036     return 2;
1037   case GlobalValue::InternalLinkage:
1038     return 3;
1039   case GlobalValue::LinkOnceAnyLinkage:
1040     return 18;
1041   case GlobalValue::ExternalWeakLinkage:
1042     return 7;
1043   case GlobalValue::CommonLinkage:
1044     return 8;
1045   case GlobalValue::PrivateLinkage:
1046     return 9;
1047   case GlobalValue::WeakODRLinkage:
1048     return 17;
1049   case GlobalValue::LinkOnceODRLinkage:
1050     return 19;
1051   case GlobalValue::AvailableExternallyLinkage:
1052     return 12;
1053   }
1054   llvm_unreachable("Invalid linkage");
1055 }
1056 
1057 static unsigned getEncodedLinkage(const GlobalValue &GV) {
1058   return getEncodedLinkage(GV.getLinkage());
1059 }
1060 
1061 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
1062   uint64_t RawFlags = 0;
1063   RawFlags |= Flags.ReadNone;
1064   RawFlags |= (Flags.ReadOnly << 1);
1065   RawFlags |= (Flags.NoRecurse << 2);
1066   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1067   RawFlags |= (Flags.NoInline << 4);
1068   RawFlags |= (Flags.AlwaysInline << 5);
1069   return RawFlags;
1070 }
1071 
1072 // Decode the flags for GlobalValue in the summary. See getDecodedGVSummaryFlags
1073 // in BitcodeReader.cpp.
1074 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
1075   uint64_t RawFlags = 0;
1076 
1077   RawFlags |= Flags.NotEligibleToImport; // bool
1078   RawFlags |= (Flags.Live << 1);
1079   RawFlags |= (Flags.DSOLocal << 2);
1080   RawFlags |= (Flags.CanAutoHide << 3);
1081 
1082   // Linkage don't need to be remapped at that time for the summary. Any future
1083   // change to the getEncodedLinkage() function will need to be taken into
1084   // account here as well.
1085   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1086 
1087   RawFlags |= (Flags.Visibility << 8); // 2 bits
1088 
1089   return RawFlags;
1090 }
1091 
1092 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1093   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1) |
1094                       (Flags.Constant << 2) | Flags.VCallVisibility << 3;
1095   return RawFlags;
1096 }
1097 
1098 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1099   switch (GV.getVisibility()) {
1100   case GlobalValue::DefaultVisibility:   return 0;
1101   case GlobalValue::HiddenVisibility:    return 1;
1102   case GlobalValue::ProtectedVisibility: return 2;
1103   }
1104   llvm_unreachable("Invalid visibility");
1105 }
1106 
1107 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1108   switch (GV.getDLLStorageClass()) {
1109   case GlobalValue::DefaultStorageClass:   return 0;
1110   case GlobalValue::DLLImportStorageClass: return 1;
1111   case GlobalValue::DLLExportStorageClass: return 2;
1112   }
1113   llvm_unreachable("Invalid DLL storage class");
1114 }
1115 
1116 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1117   switch (GV.getThreadLocalMode()) {
1118     case GlobalVariable::NotThreadLocal:         return 0;
1119     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1120     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1121     case GlobalVariable::InitialExecTLSModel:    return 3;
1122     case GlobalVariable::LocalExecTLSModel:      return 4;
1123   }
1124   llvm_unreachable("Invalid TLS model");
1125 }
1126 
1127 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1128   switch (C.getSelectionKind()) {
1129   case Comdat::Any:
1130     return bitc::COMDAT_SELECTION_KIND_ANY;
1131   case Comdat::ExactMatch:
1132     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1133   case Comdat::Largest:
1134     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1135   case Comdat::NoDeduplicate:
1136     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1137   case Comdat::SameSize:
1138     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1139   }
1140   llvm_unreachable("Invalid selection kind");
1141 }
1142 
1143 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1144   switch (GV.getUnnamedAddr()) {
1145   case GlobalValue::UnnamedAddr::None:   return 0;
1146   case GlobalValue::UnnamedAddr::Local:  return 2;
1147   case GlobalValue::UnnamedAddr::Global: return 1;
1148   }
1149   llvm_unreachable("Invalid unnamed_addr");
1150 }
1151 
1152 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1153   if (GenerateHash)
1154     Hasher.update(Str);
1155   return StrtabBuilder.add(Str);
1156 }
1157 
1158 void ModuleBitcodeWriter::writeComdats() {
1159   SmallVector<unsigned, 64> Vals;
1160   for (const Comdat *C : VE.getComdats()) {
1161     // COMDAT: [strtab offset, strtab size, selection_kind]
1162     Vals.push_back(addToStrtab(C->getName()));
1163     Vals.push_back(C->getName().size());
1164     Vals.push_back(getEncodedComdatSelectionKind(*C));
1165     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1166     Vals.clear();
1167   }
1168 }
1169 
1170 /// Write a record that will eventually hold the word offset of the
1171 /// module-level VST. For now the offset is 0, which will be backpatched
1172 /// after the real VST is written. Saves the bit offset to backpatch.
1173 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1174   // Write a placeholder value in for the offset of the real VST,
1175   // which is written after the function blocks so that it can include
1176   // the offset of each function. The placeholder offset will be
1177   // updated when the real VST is written.
1178   auto Abbv = std::make_shared<BitCodeAbbrev>();
1179   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1180   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1181   // hold the real VST offset. Must use fixed instead of VBR as we don't
1182   // know how many VBR chunks to reserve ahead of time.
1183   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1184   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1185 
1186   // Emit the placeholder
1187   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1188   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1189 
1190   // Compute and save the bit offset to the placeholder, which will be
1191   // patched when the real VST is written. We can simply subtract the 32-bit
1192   // fixed size from the current bit number to get the location to backpatch.
1193   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1194 }
1195 
1196 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1197 
1198 /// Determine the encoding to use for the given string name and length.
1199 static StringEncoding getStringEncoding(StringRef Str) {
1200   bool isChar6 = true;
1201   for (char C : Str) {
1202     if (isChar6)
1203       isChar6 = BitCodeAbbrevOp::isChar6(C);
1204     if ((unsigned char)C & 128)
1205       // don't bother scanning the rest.
1206       return SE_Fixed8;
1207   }
1208   if (isChar6)
1209     return SE_Char6;
1210   return SE_Fixed7;
1211 }
1212 
1213 /// Emit top-level description of module, including target triple, inline asm,
1214 /// descriptors for global variables, and function prototype info.
1215 /// Returns the bit offset to backpatch with the location of the real VST.
1216 void ModuleBitcodeWriter::writeModuleInfo() {
1217   // Emit various pieces of data attached to a module.
1218   if (!M.getTargetTriple().empty())
1219     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1220                       0 /*TODO*/);
1221   const std::string &DL = M.getDataLayoutStr();
1222   if (!DL.empty())
1223     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1224   if (!M.getModuleInlineAsm().empty())
1225     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1226                       0 /*TODO*/);
1227 
1228   // Emit information about sections and GC, computing how many there are. Also
1229   // compute the maximum alignment value.
1230   std::map<std::string, unsigned> SectionMap;
1231   std::map<std::string, unsigned> GCMap;
1232   MaybeAlign MaxAlignment;
1233   unsigned MaxGlobalType = 0;
1234   const auto UpdateMaxAlignment = [&MaxAlignment](const MaybeAlign A) {
1235     if (A)
1236       MaxAlignment = !MaxAlignment ? *A : std::max(*MaxAlignment, *A);
1237   };
1238   for (const GlobalVariable &GV : M.globals()) {
1239     UpdateMaxAlignment(GV.getAlign());
1240     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1241     if (GV.hasSection()) {
1242       // Give section names unique ID's.
1243       unsigned &Entry = SectionMap[std::string(GV.getSection())];
1244       if (!Entry) {
1245         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1246                           0 /*TODO*/);
1247         Entry = SectionMap.size();
1248       }
1249     }
1250   }
1251   for (const Function &F : M) {
1252     UpdateMaxAlignment(F.getAlign());
1253     if (F.hasSection()) {
1254       // Give section names unique ID's.
1255       unsigned &Entry = SectionMap[std::string(F.getSection())];
1256       if (!Entry) {
1257         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1258                           0 /*TODO*/);
1259         Entry = SectionMap.size();
1260       }
1261     }
1262     if (F.hasGC()) {
1263       // Same for GC names.
1264       unsigned &Entry = GCMap[F.getGC()];
1265       if (!Entry) {
1266         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1267                           0 /*TODO*/);
1268         Entry = GCMap.size();
1269       }
1270     }
1271   }
1272 
1273   // Emit abbrev for globals, now that we know # sections and max alignment.
1274   unsigned SimpleGVarAbbrev = 0;
1275   if (!M.global_empty()) {
1276     // Add an abbrev for common globals with no visibility or thread localness.
1277     auto Abbv = std::make_shared<BitCodeAbbrev>();
1278     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1279     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1280     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1281     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1282                               Log2_32_Ceil(MaxGlobalType+1)));
1283     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1284                                                            //| explicitType << 1
1285                                                            //| constant
1286     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1287     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1288     if (!MaxAlignment)                                     // Alignment.
1289       Abbv->Add(BitCodeAbbrevOp(0));
1290     else {
1291       unsigned MaxEncAlignment = getEncodedAlign(MaxAlignment);
1292       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1293                                Log2_32_Ceil(MaxEncAlignment+1)));
1294     }
1295     if (SectionMap.empty())                                    // Section.
1296       Abbv->Add(BitCodeAbbrevOp(0));
1297     else
1298       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1299                                Log2_32_Ceil(SectionMap.size()+1)));
1300     // Don't bother emitting vis + thread local.
1301     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1302   }
1303 
1304   SmallVector<unsigned, 64> Vals;
1305   // Emit the module's source file name.
1306   {
1307     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1308     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1309     if (Bits == SE_Char6)
1310       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1311     else if (Bits == SE_Fixed7)
1312       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1313 
1314     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1315     auto Abbv = std::make_shared<BitCodeAbbrev>();
1316     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1317     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1318     Abbv->Add(AbbrevOpToUse);
1319     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1320 
1321     for (const auto P : M.getSourceFileName())
1322       Vals.push_back((unsigned char)P);
1323 
1324     // Emit the finished record.
1325     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1326     Vals.clear();
1327   }
1328 
1329   // Emit the global variable information.
1330   for (const GlobalVariable &GV : M.globals()) {
1331     unsigned AbbrevToUse = 0;
1332 
1333     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1334     //             linkage, alignment, section, visibility, threadlocal,
1335     //             unnamed_addr, externally_initialized, dllstorageclass,
1336     //             comdat, attributes, DSO_Local]
1337     Vals.push_back(addToStrtab(GV.getName()));
1338     Vals.push_back(GV.getName().size());
1339     Vals.push_back(VE.getTypeID(GV.getValueType()));
1340     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1341     Vals.push_back(GV.isDeclaration() ? 0 :
1342                    (VE.getValueID(GV.getInitializer()) + 1));
1343     Vals.push_back(getEncodedLinkage(GV));
1344     Vals.push_back(getEncodedAlign(GV.getAlign()));
1345     Vals.push_back(GV.hasSection() ? SectionMap[std::string(GV.getSection())]
1346                                    : 0);
1347     if (GV.isThreadLocal() ||
1348         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1349         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1350         GV.isExternallyInitialized() ||
1351         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1352         GV.hasComdat() ||
1353         GV.hasAttributes() ||
1354         GV.isDSOLocal() ||
1355         GV.hasPartition()) {
1356       Vals.push_back(getEncodedVisibility(GV));
1357       Vals.push_back(getEncodedThreadLocalMode(GV));
1358       Vals.push_back(getEncodedUnnamedAddr(GV));
1359       Vals.push_back(GV.isExternallyInitialized());
1360       Vals.push_back(getEncodedDLLStorageClass(GV));
1361       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1362 
1363       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1364       Vals.push_back(VE.getAttributeListID(AL));
1365 
1366       Vals.push_back(GV.isDSOLocal());
1367       Vals.push_back(addToStrtab(GV.getPartition()));
1368       Vals.push_back(GV.getPartition().size());
1369     } else {
1370       AbbrevToUse = SimpleGVarAbbrev;
1371     }
1372 
1373     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1374     Vals.clear();
1375   }
1376 
1377   // Emit the function proto information.
1378   for (const Function &F : M) {
1379     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1380     //             linkage, paramattrs, alignment, section, visibility, gc,
1381     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1382     //             prefixdata, personalityfn, DSO_Local, addrspace]
1383     Vals.push_back(addToStrtab(F.getName()));
1384     Vals.push_back(F.getName().size());
1385     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1386     Vals.push_back(F.getCallingConv());
1387     Vals.push_back(F.isDeclaration());
1388     Vals.push_back(getEncodedLinkage(F));
1389     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1390     Vals.push_back(getEncodedAlign(F.getAlign()));
1391     Vals.push_back(F.hasSection() ? SectionMap[std::string(F.getSection())]
1392                                   : 0);
1393     Vals.push_back(getEncodedVisibility(F));
1394     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1395     Vals.push_back(getEncodedUnnamedAddr(F));
1396     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1397                                        : 0);
1398     Vals.push_back(getEncodedDLLStorageClass(F));
1399     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1400     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1401                                      : 0);
1402     Vals.push_back(
1403         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1404 
1405     Vals.push_back(F.isDSOLocal());
1406     Vals.push_back(F.getAddressSpace());
1407     Vals.push_back(addToStrtab(F.getPartition()));
1408     Vals.push_back(F.getPartition().size());
1409 
1410     unsigned AbbrevToUse = 0;
1411     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1412     Vals.clear();
1413   }
1414 
1415   // Emit the alias information.
1416   for (const GlobalAlias &A : M.aliases()) {
1417     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1418     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1419     //         DSO_Local]
1420     Vals.push_back(addToStrtab(A.getName()));
1421     Vals.push_back(A.getName().size());
1422     Vals.push_back(VE.getTypeID(A.getValueType()));
1423     Vals.push_back(A.getType()->getAddressSpace());
1424     Vals.push_back(VE.getValueID(A.getAliasee()));
1425     Vals.push_back(getEncodedLinkage(A));
1426     Vals.push_back(getEncodedVisibility(A));
1427     Vals.push_back(getEncodedDLLStorageClass(A));
1428     Vals.push_back(getEncodedThreadLocalMode(A));
1429     Vals.push_back(getEncodedUnnamedAddr(A));
1430     Vals.push_back(A.isDSOLocal());
1431     Vals.push_back(addToStrtab(A.getPartition()));
1432     Vals.push_back(A.getPartition().size());
1433 
1434     unsigned AbbrevToUse = 0;
1435     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1436     Vals.clear();
1437   }
1438 
1439   // Emit the ifunc information.
1440   for (const GlobalIFunc &I : M.ifuncs()) {
1441     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1442     //         val#, linkage, visibility, DSO_Local]
1443     Vals.push_back(addToStrtab(I.getName()));
1444     Vals.push_back(I.getName().size());
1445     Vals.push_back(VE.getTypeID(I.getValueType()));
1446     Vals.push_back(I.getType()->getAddressSpace());
1447     Vals.push_back(VE.getValueID(I.getResolver()));
1448     Vals.push_back(getEncodedLinkage(I));
1449     Vals.push_back(getEncodedVisibility(I));
1450     Vals.push_back(I.isDSOLocal());
1451     Vals.push_back(addToStrtab(I.getPartition()));
1452     Vals.push_back(I.getPartition().size());
1453     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1454     Vals.clear();
1455   }
1456 
1457   writeValueSymbolTableForwardDecl();
1458 }
1459 
1460 static uint64_t getOptimizationFlags(const Value *V) {
1461   uint64_t Flags = 0;
1462 
1463   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1464     if (OBO->hasNoSignedWrap())
1465       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1466     if (OBO->hasNoUnsignedWrap())
1467       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1468   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1469     if (PEO->isExact())
1470       Flags |= 1 << bitc::PEO_EXACT;
1471   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1472     if (FPMO->hasAllowReassoc())
1473       Flags |= bitc::AllowReassoc;
1474     if (FPMO->hasNoNaNs())
1475       Flags |= bitc::NoNaNs;
1476     if (FPMO->hasNoInfs())
1477       Flags |= bitc::NoInfs;
1478     if (FPMO->hasNoSignedZeros())
1479       Flags |= bitc::NoSignedZeros;
1480     if (FPMO->hasAllowReciprocal())
1481       Flags |= bitc::AllowReciprocal;
1482     if (FPMO->hasAllowContract())
1483       Flags |= bitc::AllowContract;
1484     if (FPMO->hasApproxFunc())
1485       Flags |= bitc::ApproxFunc;
1486   }
1487 
1488   return Flags;
1489 }
1490 
1491 void ModuleBitcodeWriter::writeValueAsMetadata(
1492     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1493   // Mimic an MDNode with a value as one operand.
1494   Value *V = MD->getValue();
1495   Record.push_back(VE.getTypeID(V->getType()));
1496   Record.push_back(VE.getValueID(V));
1497   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1498   Record.clear();
1499 }
1500 
1501 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1502                                        SmallVectorImpl<uint64_t> &Record,
1503                                        unsigned Abbrev) {
1504   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1505     Metadata *MD = N->getOperand(i);
1506     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1507            "Unexpected function-local metadata");
1508     Record.push_back(VE.getMetadataOrNullID(MD));
1509   }
1510   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1511                                     : bitc::METADATA_NODE,
1512                     Record, Abbrev);
1513   Record.clear();
1514 }
1515 
1516 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1517   // Assume the column is usually under 128, and always output the inlined-at
1518   // location (it's never more expensive than building an array size 1).
1519   auto Abbv = std::make_shared<BitCodeAbbrev>();
1520   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1521   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1522   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1523   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1524   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1525   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1526   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1527   return Stream.EmitAbbrev(std::move(Abbv));
1528 }
1529 
1530 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1531                                           SmallVectorImpl<uint64_t> &Record,
1532                                           unsigned &Abbrev) {
1533   if (!Abbrev)
1534     Abbrev = createDILocationAbbrev();
1535 
1536   Record.push_back(N->isDistinct());
1537   Record.push_back(N->getLine());
1538   Record.push_back(N->getColumn());
1539   Record.push_back(VE.getMetadataID(N->getScope()));
1540   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1541   Record.push_back(N->isImplicitCode());
1542 
1543   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1544   Record.clear();
1545 }
1546 
1547 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1548   // Assume the column is usually under 128, and always output the inlined-at
1549   // location (it's never more expensive than building an array size 1).
1550   auto Abbv = std::make_shared<BitCodeAbbrev>();
1551   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1552   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1553   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1554   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1555   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1556   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1557   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1558   return Stream.EmitAbbrev(std::move(Abbv));
1559 }
1560 
1561 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1562                                              SmallVectorImpl<uint64_t> &Record,
1563                                              unsigned &Abbrev) {
1564   if (!Abbrev)
1565     Abbrev = createGenericDINodeAbbrev();
1566 
1567   Record.push_back(N->isDistinct());
1568   Record.push_back(N->getTag());
1569   Record.push_back(0); // Per-tag version field; unused for now.
1570 
1571   for (auto &I : N->operands())
1572     Record.push_back(VE.getMetadataOrNullID(I));
1573 
1574   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1575   Record.clear();
1576 }
1577 
1578 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1579                                           SmallVectorImpl<uint64_t> &Record,
1580                                           unsigned Abbrev) {
1581   const uint64_t Version = 2 << 1;
1582   Record.push_back((uint64_t)N->isDistinct() | Version);
1583   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1584   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1585   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1586   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1587 
1588   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1589   Record.clear();
1590 }
1591 
1592 void ModuleBitcodeWriter::writeDIGenericSubrange(
1593     const DIGenericSubrange *N, SmallVectorImpl<uint64_t> &Record,
1594     unsigned Abbrev) {
1595   Record.push_back((uint64_t)N->isDistinct());
1596   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1597   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1598   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1599   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1600 
1601   Stream.EmitRecord(bitc::METADATA_GENERIC_SUBRANGE, Record, Abbrev);
1602   Record.clear();
1603 }
1604 
1605 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1606   if ((int64_t)V >= 0)
1607     Vals.push_back(V << 1);
1608   else
1609     Vals.push_back((-V << 1) | 1);
1610 }
1611 
1612 static void emitWideAPInt(SmallVectorImpl<uint64_t> &Vals, const APInt &A) {
1613   // We have an arbitrary precision integer value to write whose
1614   // bit width is > 64. However, in canonical unsigned integer
1615   // format it is likely that the high bits are going to be zero.
1616   // So, we only write the number of active words.
1617   unsigned NumWords = A.getActiveWords();
1618   const uint64_t *RawData = A.getRawData();
1619   for (unsigned i = 0; i < NumWords; i++)
1620     emitSignedInt64(Vals, RawData[i]);
1621 }
1622 
1623 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1624                                             SmallVectorImpl<uint64_t> &Record,
1625                                             unsigned Abbrev) {
1626   const uint64_t IsBigInt = 1 << 2;
1627   Record.push_back(IsBigInt | (N->isUnsigned() << 1) | N->isDistinct());
1628   Record.push_back(N->getValue().getBitWidth());
1629   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1630   emitWideAPInt(Record, N->getValue());
1631 
1632   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1633   Record.clear();
1634 }
1635 
1636 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1637                                            SmallVectorImpl<uint64_t> &Record,
1638                                            unsigned Abbrev) {
1639   Record.push_back(N->isDistinct());
1640   Record.push_back(N->getTag());
1641   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1642   Record.push_back(N->getSizeInBits());
1643   Record.push_back(N->getAlignInBits());
1644   Record.push_back(N->getEncoding());
1645   Record.push_back(N->getFlags());
1646 
1647   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1648   Record.clear();
1649 }
1650 
1651 void ModuleBitcodeWriter::writeDIStringType(const DIStringType *N,
1652                                             SmallVectorImpl<uint64_t> &Record,
1653                                             unsigned Abbrev) {
1654   Record.push_back(N->isDistinct());
1655   Record.push_back(N->getTag());
1656   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1657   Record.push_back(VE.getMetadataOrNullID(N->getStringLength()));
1658   Record.push_back(VE.getMetadataOrNullID(N->getStringLengthExp()));
1659   Record.push_back(N->getSizeInBits());
1660   Record.push_back(N->getAlignInBits());
1661   Record.push_back(N->getEncoding());
1662 
1663   Stream.EmitRecord(bitc::METADATA_STRING_TYPE, Record, Abbrev);
1664   Record.clear();
1665 }
1666 
1667 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1668                                              SmallVectorImpl<uint64_t> &Record,
1669                                              unsigned Abbrev) {
1670   Record.push_back(N->isDistinct());
1671   Record.push_back(N->getTag());
1672   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1673   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1674   Record.push_back(N->getLine());
1675   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1676   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1677   Record.push_back(N->getSizeInBits());
1678   Record.push_back(N->getAlignInBits());
1679   Record.push_back(N->getOffsetInBits());
1680   Record.push_back(N->getFlags());
1681   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1682 
1683   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1684   // that there is no DWARF address space associated with DIDerivedType.
1685   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1686     Record.push_back(*DWARFAddressSpace + 1);
1687   else
1688     Record.push_back(0);
1689 
1690   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1691 
1692   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1693   Record.clear();
1694 }
1695 
1696 void ModuleBitcodeWriter::writeDICompositeType(
1697     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1698     unsigned Abbrev) {
1699   const unsigned IsNotUsedInOldTypeRef = 0x2;
1700   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1701   Record.push_back(N->getTag());
1702   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1703   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1704   Record.push_back(N->getLine());
1705   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1706   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1707   Record.push_back(N->getSizeInBits());
1708   Record.push_back(N->getAlignInBits());
1709   Record.push_back(N->getOffsetInBits());
1710   Record.push_back(N->getFlags());
1711   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1712   Record.push_back(N->getRuntimeLang());
1713   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1714   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1715   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1716   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1717   Record.push_back(VE.getMetadataOrNullID(N->getRawDataLocation()));
1718   Record.push_back(VE.getMetadataOrNullID(N->getRawAssociated()));
1719   Record.push_back(VE.getMetadataOrNullID(N->getRawAllocated()));
1720   Record.push_back(VE.getMetadataOrNullID(N->getRawRank()));
1721   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1722 
1723   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1724   Record.clear();
1725 }
1726 
1727 void ModuleBitcodeWriter::writeDISubroutineType(
1728     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1729     unsigned Abbrev) {
1730   const unsigned HasNoOldTypeRefs = 0x2;
1731   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1732   Record.push_back(N->getFlags());
1733   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1734   Record.push_back(N->getCC());
1735 
1736   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1737   Record.clear();
1738 }
1739 
1740 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1741                                       SmallVectorImpl<uint64_t> &Record,
1742                                       unsigned Abbrev) {
1743   Record.push_back(N->isDistinct());
1744   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1745   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1746   if (N->getRawChecksum()) {
1747     Record.push_back(N->getRawChecksum()->Kind);
1748     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1749   } else {
1750     // Maintain backwards compatibility with the old internal representation of
1751     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1752     Record.push_back(0);
1753     Record.push_back(VE.getMetadataOrNullID(nullptr));
1754   }
1755   auto Source = N->getRawSource();
1756   if (Source)
1757     Record.push_back(VE.getMetadataOrNullID(*Source));
1758 
1759   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1760   Record.clear();
1761 }
1762 
1763 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1764                                              SmallVectorImpl<uint64_t> &Record,
1765                                              unsigned Abbrev) {
1766   assert(N->isDistinct() && "Expected distinct compile units");
1767   Record.push_back(/* IsDistinct */ true);
1768   Record.push_back(N->getSourceLanguage());
1769   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1770   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1771   Record.push_back(N->isOptimized());
1772   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1773   Record.push_back(N->getRuntimeVersion());
1774   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1775   Record.push_back(N->getEmissionKind());
1776   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1777   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1778   Record.push_back(/* subprograms */ 0);
1779   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1780   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1781   Record.push_back(N->getDWOId());
1782   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1783   Record.push_back(N->getSplitDebugInlining());
1784   Record.push_back(N->getDebugInfoForProfiling());
1785   Record.push_back((unsigned)N->getNameTableKind());
1786   Record.push_back(N->getRangesBaseAddress());
1787   Record.push_back(VE.getMetadataOrNullID(N->getRawSysRoot()));
1788   Record.push_back(VE.getMetadataOrNullID(N->getRawSDK()));
1789 
1790   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1791   Record.clear();
1792 }
1793 
1794 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1795                                             SmallVectorImpl<uint64_t> &Record,
1796                                             unsigned Abbrev) {
1797   const uint64_t HasUnitFlag = 1 << 1;
1798   const uint64_t HasSPFlagsFlag = 1 << 2;
1799   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
1800   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1801   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1802   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1803   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1804   Record.push_back(N->getLine());
1805   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1806   Record.push_back(N->getScopeLine());
1807   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1808   Record.push_back(N->getSPFlags());
1809   Record.push_back(N->getVirtualIndex());
1810   Record.push_back(N->getFlags());
1811   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1812   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1813   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1814   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
1815   Record.push_back(N->getThisAdjustment());
1816   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
1817   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1818 
1819   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1820   Record.clear();
1821 }
1822 
1823 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1824                                               SmallVectorImpl<uint64_t> &Record,
1825                                               unsigned Abbrev) {
1826   Record.push_back(N->isDistinct());
1827   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1828   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1829   Record.push_back(N->getLine());
1830   Record.push_back(N->getColumn());
1831 
1832   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1833   Record.clear();
1834 }
1835 
1836 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1837     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1838     unsigned Abbrev) {
1839   Record.push_back(N->isDistinct());
1840   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1841   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1842   Record.push_back(N->getDiscriminator());
1843 
1844   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1845   Record.clear();
1846 }
1847 
1848 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
1849                                              SmallVectorImpl<uint64_t> &Record,
1850                                              unsigned Abbrev) {
1851   Record.push_back(N->isDistinct());
1852   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1853   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
1854   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1855   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1856   Record.push_back(N->getLineNo());
1857 
1858   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
1859   Record.clear();
1860 }
1861 
1862 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1863                                            SmallVectorImpl<uint64_t> &Record,
1864                                            unsigned Abbrev) {
1865   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1866   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1867   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1868 
1869   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1870   Record.clear();
1871 }
1872 
1873 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1874                                        SmallVectorImpl<uint64_t> &Record,
1875                                        unsigned Abbrev) {
1876   Record.push_back(N->isDistinct());
1877   Record.push_back(N->getMacinfoType());
1878   Record.push_back(N->getLine());
1879   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1880   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1881 
1882   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1883   Record.clear();
1884 }
1885 
1886 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1887                                            SmallVectorImpl<uint64_t> &Record,
1888                                            unsigned Abbrev) {
1889   Record.push_back(N->isDistinct());
1890   Record.push_back(N->getMacinfoType());
1891   Record.push_back(N->getLine());
1892   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1893   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1894 
1895   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1896   Record.clear();
1897 }
1898 
1899 void ModuleBitcodeWriter::writeDIArgList(const DIArgList *N,
1900                                          SmallVectorImpl<uint64_t> &Record,
1901                                          unsigned Abbrev) {
1902   Record.reserve(N->getArgs().size());
1903   for (ValueAsMetadata *MD : N->getArgs())
1904     Record.push_back(VE.getMetadataID(MD));
1905 
1906   Stream.EmitRecord(bitc::METADATA_ARG_LIST, Record, Abbrev);
1907   Record.clear();
1908 }
1909 
1910 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1911                                         SmallVectorImpl<uint64_t> &Record,
1912                                         unsigned Abbrev) {
1913   Record.push_back(N->isDistinct());
1914   for (auto &I : N->operands())
1915     Record.push_back(VE.getMetadataOrNullID(I));
1916   Record.push_back(N->getLineNo());
1917   Record.push_back(N->getIsDecl());
1918 
1919   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1920   Record.clear();
1921 }
1922 
1923 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1924     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1925     unsigned Abbrev) {
1926   Record.push_back(N->isDistinct());
1927   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1928   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1929   Record.push_back(N->isDefault());
1930 
1931   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1932   Record.clear();
1933 }
1934 
1935 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1936     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1937     unsigned Abbrev) {
1938   Record.push_back(N->isDistinct());
1939   Record.push_back(N->getTag());
1940   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1941   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1942   Record.push_back(N->isDefault());
1943   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1944 
1945   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1946   Record.clear();
1947 }
1948 
1949 void ModuleBitcodeWriter::writeDIGlobalVariable(
1950     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1951     unsigned Abbrev) {
1952   const uint64_t Version = 2 << 1;
1953   Record.push_back((uint64_t)N->isDistinct() | Version);
1954   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1955   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1956   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1957   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1958   Record.push_back(N->getLine());
1959   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1960   Record.push_back(N->isLocalToUnit());
1961   Record.push_back(N->isDefinition());
1962   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1963   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
1964   Record.push_back(N->getAlignInBits());
1965 
1966   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1967   Record.clear();
1968 }
1969 
1970 void ModuleBitcodeWriter::writeDILocalVariable(
1971     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
1972     unsigned Abbrev) {
1973   // In order to support all possible bitcode formats in BitcodeReader we need
1974   // to distinguish the following cases:
1975   // 1) Record has no artificial tag (Record[1]),
1976   //   has no obsolete inlinedAt field (Record[9]).
1977   //   In this case Record size will be 8, HasAlignment flag is false.
1978   // 2) Record has artificial tag (Record[1]),
1979   //   has no obsolete inlignedAt field (Record[9]).
1980   //   In this case Record size will be 9, HasAlignment flag is false.
1981   // 3) Record has both artificial tag (Record[1]) and
1982   //   obsolete inlignedAt field (Record[9]).
1983   //   In this case Record size will be 10, HasAlignment flag is false.
1984   // 4) Record has neither artificial tag, nor inlignedAt field, but
1985   //   HasAlignment flag is true and Record[8] contains alignment value.
1986   const uint64_t HasAlignmentFlag = 1 << 1;
1987   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
1988   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1989   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1990   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1991   Record.push_back(N->getLine());
1992   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1993   Record.push_back(N->getArg());
1994   Record.push_back(N->getFlags());
1995   Record.push_back(N->getAlignInBits());
1996 
1997   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1998   Record.clear();
1999 }
2000 
2001 void ModuleBitcodeWriter::writeDILabel(
2002     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
2003     unsigned Abbrev) {
2004   Record.push_back((uint64_t)N->isDistinct());
2005   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2006   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2007   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2008   Record.push_back(N->getLine());
2009 
2010   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
2011   Record.clear();
2012 }
2013 
2014 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
2015                                             SmallVectorImpl<uint64_t> &Record,
2016                                             unsigned Abbrev) {
2017   Record.reserve(N->getElements().size() + 1);
2018   const uint64_t Version = 3 << 1;
2019   Record.push_back((uint64_t)N->isDistinct() | Version);
2020   Record.append(N->elements_begin(), N->elements_end());
2021 
2022   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
2023   Record.clear();
2024 }
2025 
2026 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
2027     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
2028     unsigned Abbrev) {
2029   Record.push_back(N->isDistinct());
2030   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
2031   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
2032 
2033   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
2034   Record.clear();
2035 }
2036 
2037 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
2038                                               SmallVectorImpl<uint64_t> &Record,
2039                                               unsigned Abbrev) {
2040   Record.push_back(N->isDistinct());
2041   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2042   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2043   Record.push_back(N->getLine());
2044   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
2045   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
2046   Record.push_back(N->getAttributes());
2047   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2048 
2049   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
2050   Record.clear();
2051 }
2052 
2053 void ModuleBitcodeWriter::writeDIImportedEntity(
2054     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
2055     unsigned Abbrev) {
2056   Record.push_back(N->isDistinct());
2057   Record.push_back(N->getTag());
2058   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2059   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
2060   Record.push_back(N->getLine());
2061   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2062   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
2063 
2064   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
2065   Record.clear();
2066 }
2067 
2068 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
2069   auto Abbv = std::make_shared<BitCodeAbbrev>();
2070   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
2071   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2072   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2073   return Stream.EmitAbbrev(std::move(Abbv));
2074 }
2075 
2076 void ModuleBitcodeWriter::writeNamedMetadata(
2077     SmallVectorImpl<uint64_t> &Record) {
2078   if (M.named_metadata_empty())
2079     return;
2080 
2081   unsigned Abbrev = createNamedMetadataAbbrev();
2082   for (const NamedMDNode &NMD : M.named_metadata()) {
2083     // Write name.
2084     StringRef Str = NMD.getName();
2085     Record.append(Str.bytes_begin(), Str.bytes_end());
2086     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
2087     Record.clear();
2088 
2089     // Write named metadata operands.
2090     for (const MDNode *N : NMD.operands())
2091       Record.push_back(VE.getMetadataID(N));
2092     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
2093     Record.clear();
2094   }
2095 }
2096 
2097 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
2098   auto Abbv = std::make_shared<BitCodeAbbrev>();
2099   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
2100   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
2101   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
2102   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2103   return Stream.EmitAbbrev(std::move(Abbv));
2104 }
2105 
2106 /// Write out a record for MDString.
2107 ///
2108 /// All the metadata strings in a metadata block are emitted in a single
2109 /// record.  The sizes and strings themselves are shoved into a blob.
2110 void ModuleBitcodeWriter::writeMetadataStrings(
2111     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
2112   if (Strings.empty())
2113     return;
2114 
2115   // Start the record with the number of strings.
2116   Record.push_back(bitc::METADATA_STRINGS);
2117   Record.push_back(Strings.size());
2118 
2119   // Emit the sizes of the strings in the blob.
2120   SmallString<256> Blob;
2121   {
2122     BitstreamWriter W(Blob);
2123     for (const Metadata *MD : Strings)
2124       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
2125     W.FlushToWord();
2126   }
2127 
2128   // Add the offset to the strings to the record.
2129   Record.push_back(Blob.size());
2130 
2131   // Add the strings to the blob.
2132   for (const Metadata *MD : Strings)
2133     Blob.append(cast<MDString>(MD)->getString());
2134 
2135   // Emit the final record.
2136   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
2137   Record.clear();
2138 }
2139 
2140 // Generates an enum to use as an index in the Abbrev array of Metadata record.
2141 enum MetadataAbbrev : unsigned {
2142 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
2143 #include "llvm/IR/Metadata.def"
2144   LastPlusOne
2145 };
2146 
2147 void ModuleBitcodeWriter::writeMetadataRecords(
2148     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2149     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2150   if (MDs.empty())
2151     return;
2152 
2153   // Initialize MDNode abbreviations.
2154 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2155 #include "llvm/IR/Metadata.def"
2156 
2157   for (const Metadata *MD : MDs) {
2158     if (IndexPos)
2159       IndexPos->push_back(Stream.GetCurrentBitNo());
2160     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2161       assert(N->isResolved() && "Expected forward references to be resolved");
2162 
2163       switch (N->getMetadataID()) {
2164       default:
2165         llvm_unreachable("Invalid MDNode subclass");
2166 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2167   case Metadata::CLASS##Kind:                                                  \
2168     if (MDAbbrevs)                                                             \
2169       write##CLASS(cast<CLASS>(N), Record,                                     \
2170                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2171     else                                                                       \
2172       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2173     continue;
2174 #include "llvm/IR/Metadata.def"
2175       }
2176     }
2177     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2178   }
2179 }
2180 
2181 void ModuleBitcodeWriter::writeModuleMetadata() {
2182   if (!VE.hasMDs() && M.named_metadata_empty())
2183     return;
2184 
2185   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2186   SmallVector<uint64_t, 64> Record;
2187 
2188   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2189   // block and load any metadata.
2190   std::vector<unsigned> MDAbbrevs;
2191 
2192   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2193   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2194   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2195       createGenericDINodeAbbrev();
2196 
2197   auto Abbv = std::make_shared<BitCodeAbbrev>();
2198   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2199   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2200   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2201   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2202 
2203   Abbv = std::make_shared<BitCodeAbbrev>();
2204   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2205   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2206   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2207   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2208 
2209   // Emit MDStrings together upfront.
2210   writeMetadataStrings(VE.getMDStrings(), Record);
2211 
2212   // We only emit an index for the metadata record if we have more than a given
2213   // (naive) threshold of metadatas, otherwise it is not worth it.
2214   if (VE.getNonMDStrings().size() > IndexThreshold) {
2215     // Write a placeholder value in for the offset of the metadata index,
2216     // which is written after the records, so that it can include
2217     // the offset of each entry. The placeholder offset will be
2218     // updated after all records are emitted.
2219     uint64_t Vals[] = {0, 0};
2220     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2221   }
2222 
2223   // Compute and save the bit offset to the current position, which will be
2224   // patched when we emit the index later. We can simply subtract the 64-bit
2225   // fixed size from the current bit number to get the location to backpatch.
2226   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2227 
2228   // This index will contain the bitpos for each individual record.
2229   std::vector<uint64_t> IndexPos;
2230   IndexPos.reserve(VE.getNonMDStrings().size());
2231 
2232   // Write all the records
2233   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2234 
2235   if (VE.getNonMDStrings().size() > IndexThreshold) {
2236     // Now that we have emitted all the records we will emit the index. But
2237     // first
2238     // backpatch the forward reference so that the reader can skip the records
2239     // efficiently.
2240     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2241                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2242 
2243     // Delta encode the index.
2244     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2245     for (auto &Elt : IndexPos) {
2246       auto EltDelta = Elt - PreviousValue;
2247       PreviousValue = Elt;
2248       Elt = EltDelta;
2249     }
2250     // Emit the index record.
2251     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2252     IndexPos.clear();
2253   }
2254 
2255   // Write the named metadata now.
2256   writeNamedMetadata(Record);
2257 
2258   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2259     SmallVector<uint64_t, 4> Record;
2260     Record.push_back(VE.getValueID(&GO));
2261     pushGlobalMetadataAttachment(Record, GO);
2262     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2263   };
2264   for (const Function &F : M)
2265     if (F.isDeclaration() && F.hasMetadata())
2266       AddDeclAttachedMetadata(F);
2267   // FIXME: Only store metadata for declarations here, and move data for global
2268   // variable definitions to a separate block (PR28134).
2269   for (const GlobalVariable &GV : M.globals())
2270     if (GV.hasMetadata())
2271       AddDeclAttachedMetadata(GV);
2272 
2273   Stream.ExitBlock();
2274 }
2275 
2276 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2277   if (!VE.hasMDs())
2278     return;
2279 
2280   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2281   SmallVector<uint64_t, 64> Record;
2282   writeMetadataStrings(VE.getMDStrings(), Record);
2283   writeMetadataRecords(VE.getNonMDStrings(), Record);
2284   Stream.ExitBlock();
2285 }
2286 
2287 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2288     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2289   // [n x [id, mdnode]]
2290   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2291   GO.getAllMetadata(MDs);
2292   for (const auto &I : MDs) {
2293     Record.push_back(I.first);
2294     Record.push_back(VE.getMetadataID(I.second));
2295   }
2296 }
2297 
2298 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2299   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2300 
2301   SmallVector<uint64_t, 64> Record;
2302 
2303   if (F.hasMetadata()) {
2304     pushGlobalMetadataAttachment(Record, F);
2305     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2306     Record.clear();
2307   }
2308 
2309   // Write metadata attachments
2310   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2311   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2312   for (const BasicBlock &BB : F)
2313     for (const Instruction &I : BB) {
2314       MDs.clear();
2315       I.getAllMetadataOtherThanDebugLoc(MDs);
2316 
2317       // If no metadata, ignore instruction.
2318       if (MDs.empty()) continue;
2319 
2320       Record.push_back(VE.getInstructionID(&I));
2321 
2322       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2323         Record.push_back(MDs[i].first);
2324         Record.push_back(VE.getMetadataID(MDs[i].second));
2325       }
2326       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2327       Record.clear();
2328     }
2329 
2330   Stream.ExitBlock();
2331 }
2332 
2333 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2334   SmallVector<uint64_t, 64> Record;
2335 
2336   // Write metadata kinds
2337   // METADATA_KIND - [n x [id, name]]
2338   SmallVector<StringRef, 8> Names;
2339   M.getMDKindNames(Names);
2340 
2341   if (Names.empty()) return;
2342 
2343   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2344 
2345   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2346     Record.push_back(MDKindID);
2347     StringRef KName = Names[MDKindID];
2348     Record.append(KName.begin(), KName.end());
2349 
2350     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2351     Record.clear();
2352   }
2353 
2354   Stream.ExitBlock();
2355 }
2356 
2357 void ModuleBitcodeWriter::writeOperandBundleTags() {
2358   // Write metadata kinds
2359   //
2360   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2361   //
2362   // OPERAND_BUNDLE_TAG - [strchr x N]
2363 
2364   SmallVector<StringRef, 8> Tags;
2365   M.getOperandBundleTags(Tags);
2366 
2367   if (Tags.empty())
2368     return;
2369 
2370   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2371 
2372   SmallVector<uint64_t, 64> Record;
2373 
2374   for (auto Tag : Tags) {
2375     Record.append(Tag.begin(), Tag.end());
2376 
2377     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2378     Record.clear();
2379   }
2380 
2381   Stream.ExitBlock();
2382 }
2383 
2384 void ModuleBitcodeWriter::writeSyncScopeNames() {
2385   SmallVector<StringRef, 8> SSNs;
2386   M.getContext().getSyncScopeNames(SSNs);
2387   if (SSNs.empty())
2388     return;
2389 
2390   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2391 
2392   SmallVector<uint64_t, 64> Record;
2393   for (auto SSN : SSNs) {
2394     Record.append(SSN.begin(), SSN.end());
2395     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2396     Record.clear();
2397   }
2398 
2399   Stream.ExitBlock();
2400 }
2401 
2402 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2403                                          bool isGlobal) {
2404   if (FirstVal == LastVal) return;
2405 
2406   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2407 
2408   unsigned AggregateAbbrev = 0;
2409   unsigned String8Abbrev = 0;
2410   unsigned CString7Abbrev = 0;
2411   unsigned CString6Abbrev = 0;
2412   // If this is a constant pool for the module, emit module-specific abbrevs.
2413   if (isGlobal) {
2414     // Abbrev for CST_CODE_AGGREGATE.
2415     auto Abbv = std::make_shared<BitCodeAbbrev>();
2416     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2417     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2418     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2419     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2420 
2421     // Abbrev for CST_CODE_STRING.
2422     Abbv = std::make_shared<BitCodeAbbrev>();
2423     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2424     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2425     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2426     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2427     // Abbrev for CST_CODE_CSTRING.
2428     Abbv = std::make_shared<BitCodeAbbrev>();
2429     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2430     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2431     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2432     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2433     // Abbrev for CST_CODE_CSTRING.
2434     Abbv = std::make_shared<BitCodeAbbrev>();
2435     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2436     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2437     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2438     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2439   }
2440 
2441   SmallVector<uint64_t, 64> Record;
2442 
2443   const ValueEnumerator::ValueList &Vals = VE.getValues();
2444   Type *LastTy = nullptr;
2445   for (unsigned i = FirstVal; i != LastVal; ++i) {
2446     const Value *V = Vals[i].first;
2447     // If we need to switch types, do so now.
2448     if (V->getType() != LastTy) {
2449       LastTy = V->getType();
2450       Record.push_back(VE.getTypeID(LastTy));
2451       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2452                         CONSTANTS_SETTYPE_ABBREV);
2453       Record.clear();
2454     }
2455 
2456     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2457       Record.push_back(
2458           unsigned(IA->hasSideEffects()) | unsigned(IA->isAlignStack()) << 1 |
2459           unsigned(IA->getDialect() & 1) << 2 | unsigned(IA->canThrow()) << 3);
2460 
2461       // Add the asm string.
2462       const std::string &AsmStr = IA->getAsmString();
2463       Record.push_back(AsmStr.size());
2464       Record.append(AsmStr.begin(), AsmStr.end());
2465 
2466       // Add the constraint string.
2467       const std::string &ConstraintStr = IA->getConstraintString();
2468       Record.push_back(ConstraintStr.size());
2469       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2470       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2471       Record.clear();
2472       continue;
2473     }
2474     const Constant *C = cast<Constant>(V);
2475     unsigned Code = -1U;
2476     unsigned AbbrevToUse = 0;
2477     if (C->isNullValue()) {
2478       Code = bitc::CST_CODE_NULL;
2479     } else if (isa<PoisonValue>(C)) {
2480       Code = bitc::CST_CODE_POISON;
2481     } else if (isa<UndefValue>(C)) {
2482       Code = bitc::CST_CODE_UNDEF;
2483     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2484       if (IV->getBitWidth() <= 64) {
2485         uint64_t V = IV->getSExtValue();
2486         emitSignedInt64(Record, V);
2487         Code = bitc::CST_CODE_INTEGER;
2488         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2489       } else {                             // Wide integers, > 64 bits in size.
2490         emitWideAPInt(Record, IV->getValue());
2491         Code = bitc::CST_CODE_WIDE_INTEGER;
2492       }
2493     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2494       Code = bitc::CST_CODE_FLOAT;
2495       Type *Ty = CFP->getType();
2496       if (Ty->isHalfTy() || Ty->isBFloatTy() || Ty->isFloatTy() ||
2497           Ty->isDoubleTy()) {
2498         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2499       } else if (Ty->isX86_FP80Ty()) {
2500         // api needed to prevent premature destruction
2501         // bits are not in the same order as a normal i80 APInt, compensate.
2502         APInt api = CFP->getValueAPF().bitcastToAPInt();
2503         const uint64_t *p = api.getRawData();
2504         Record.push_back((p[1] << 48) | (p[0] >> 16));
2505         Record.push_back(p[0] & 0xffffLL);
2506       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2507         APInt api = CFP->getValueAPF().bitcastToAPInt();
2508         const uint64_t *p = api.getRawData();
2509         Record.push_back(p[0]);
2510         Record.push_back(p[1]);
2511       } else {
2512         assert(0 && "Unknown FP type!");
2513       }
2514     } else if (isa<ConstantDataSequential>(C) &&
2515                cast<ConstantDataSequential>(C)->isString()) {
2516       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2517       // Emit constant strings specially.
2518       unsigned NumElts = Str->getNumElements();
2519       // If this is a null-terminated string, use the denser CSTRING encoding.
2520       if (Str->isCString()) {
2521         Code = bitc::CST_CODE_CSTRING;
2522         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2523       } else {
2524         Code = bitc::CST_CODE_STRING;
2525         AbbrevToUse = String8Abbrev;
2526       }
2527       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2528       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2529       for (unsigned i = 0; i != NumElts; ++i) {
2530         unsigned char V = Str->getElementAsInteger(i);
2531         Record.push_back(V);
2532         isCStr7 &= (V & 128) == 0;
2533         if (isCStrChar6)
2534           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2535       }
2536 
2537       if (isCStrChar6)
2538         AbbrevToUse = CString6Abbrev;
2539       else if (isCStr7)
2540         AbbrevToUse = CString7Abbrev;
2541     } else if (const ConstantDataSequential *CDS =
2542                   dyn_cast<ConstantDataSequential>(C)) {
2543       Code = bitc::CST_CODE_DATA;
2544       Type *EltTy = CDS->getElementType();
2545       if (isa<IntegerType>(EltTy)) {
2546         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2547           Record.push_back(CDS->getElementAsInteger(i));
2548       } else {
2549         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2550           Record.push_back(
2551               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2552       }
2553     } else if (isa<ConstantAggregate>(C)) {
2554       Code = bitc::CST_CODE_AGGREGATE;
2555       for (const Value *Op : C->operands())
2556         Record.push_back(VE.getValueID(Op));
2557       AbbrevToUse = AggregateAbbrev;
2558     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2559       switch (CE->getOpcode()) {
2560       default:
2561         if (Instruction::isCast(CE->getOpcode())) {
2562           Code = bitc::CST_CODE_CE_CAST;
2563           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2564           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2565           Record.push_back(VE.getValueID(C->getOperand(0)));
2566           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2567         } else {
2568           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2569           Code = bitc::CST_CODE_CE_BINOP;
2570           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2571           Record.push_back(VE.getValueID(C->getOperand(0)));
2572           Record.push_back(VE.getValueID(C->getOperand(1)));
2573           uint64_t Flags = getOptimizationFlags(CE);
2574           if (Flags != 0)
2575             Record.push_back(Flags);
2576         }
2577         break;
2578       case Instruction::FNeg: {
2579         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2580         Code = bitc::CST_CODE_CE_UNOP;
2581         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2582         Record.push_back(VE.getValueID(C->getOperand(0)));
2583         uint64_t Flags = getOptimizationFlags(CE);
2584         if (Flags != 0)
2585           Record.push_back(Flags);
2586         break;
2587       }
2588       case Instruction::GetElementPtr: {
2589         Code = bitc::CST_CODE_CE_GEP;
2590         const auto *GO = cast<GEPOperator>(C);
2591         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2592         if (Optional<unsigned> Idx = GO->getInRangeIndex()) {
2593           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2594           Record.push_back((*Idx << 1) | GO->isInBounds());
2595         } else if (GO->isInBounds())
2596           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2597         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2598           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2599           Record.push_back(VE.getValueID(C->getOperand(i)));
2600         }
2601         break;
2602       }
2603       case Instruction::Select:
2604         Code = bitc::CST_CODE_CE_SELECT;
2605         Record.push_back(VE.getValueID(C->getOperand(0)));
2606         Record.push_back(VE.getValueID(C->getOperand(1)));
2607         Record.push_back(VE.getValueID(C->getOperand(2)));
2608         break;
2609       case Instruction::ExtractElement:
2610         Code = bitc::CST_CODE_CE_EXTRACTELT;
2611         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2612         Record.push_back(VE.getValueID(C->getOperand(0)));
2613         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2614         Record.push_back(VE.getValueID(C->getOperand(1)));
2615         break;
2616       case Instruction::InsertElement:
2617         Code = bitc::CST_CODE_CE_INSERTELT;
2618         Record.push_back(VE.getValueID(C->getOperand(0)));
2619         Record.push_back(VE.getValueID(C->getOperand(1)));
2620         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2621         Record.push_back(VE.getValueID(C->getOperand(2)));
2622         break;
2623       case Instruction::ShuffleVector:
2624         // If the return type and argument types are the same, this is a
2625         // standard shufflevector instruction.  If the types are different,
2626         // then the shuffle is widening or truncating the input vectors, and
2627         // the argument type must also be encoded.
2628         if (C->getType() == C->getOperand(0)->getType()) {
2629           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2630         } else {
2631           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2632           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2633         }
2634         Record.push_back(VE.getValueID(C->getOperand(0)));
2635         Record.push_back(VE.getValueID(C->getOperand(1)));
2636         Record.push_back(VE.getValueID(CE->getShuffleMaskForBitcode()));
2637         break;
2638       case Instruction::ICmp:
2639       case Instruction::FCmp:
2640         Code = bitc::CST_CODE_CE_CMP;
2641         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2642         Record.push_back(VE.getValueID(C->getOperand(0)));
2643         Record.push_back(VE.getValueID(C->getOperand(1)));
2644         Record.push_back(CE->getPredicate());
2645         break;
2646       }
2647     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2648       Code = bitc::CST_CODE_BLOCKADDRESS;
2649       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2650       Record.push_back(VE.getValueID(BA->getFunction()));
2651       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2652     } else if (const auto *Equiv = dyn_cast<DSOLocalEquivalent>(C)) {
2653       Code = bitc::CST_CODE_DSO_LOCAL_EQUIVALENT;
2654       Record.push_back(VE.getTypeID(Equiv->getGlobalValue()->getType()));
2655       Record.push_back(VE.getValueID(Equiv->getGlobalValue()));
2656     } else {
2657 #ifndef NDEBUG
2658       C->dump();
2659 #endif
2660       llvm_unreachable("Unknown constant!");
2661     }
2662     Stream.EmitRecord(Code, Record, AbbrevToUse);
2663     Record.clear();
2664   }
2665 
2666   Stream.ExitBlock();
2667 }
2668 
2669 void ModuleBitcodeWriter::writeModuleConstants() {
2670   const ValueEnumerator::ValueList &Vals = VE.getValues();
2671 
2672   // Find the first constant to emit, which is the first non-globalvalue value.
2673   // We know globalvalues have been emitted by WriteModuleInfo.
2674   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2675     if (!isa<GlobalValue>(Vals[i].first)) {
2676       writeConstants(i, Vals.size(), true);
2677       return;
2678     }
2679   }
2680 }
2681 
2682 /// pushValueAndType - The file has to encode both the value and type id for
2683 /// many values, because we need to know what type to create for forward
2684 /// references.  However, most operands are not forward references, so this type
2685 /// field is not needed.
2686 ///
2687 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2688 /// instruction ID, then it is a forward reference, and it also includes the
2689 /// type ID.  The value ID that is written is encoded relative to the InstID.
2690 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2691                                            SmallVectorImpl<unsigned> &Vals) {
2692   unsigned ValID = VE.getValueID(V);
2693   // Make encoding relative to the InstID.
2694   Vals.push_back(InstID - ValID);
2695   if (ValID >= InstID) {
2696     Vals.push_back(VE.getTypeID(V->getType()));
2697     return true;
2698   }
2699   return false;
2700 }
2701 
2702 void ModuleBitcodeWriter::writeOperandBundles(const CallBase &CS,
2703                                               unsigned InstID) {
2704   SmallVector<unsigned, 64> Record;
2705   LLVMContext &C = CS.getContext();
2706 
2707   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2708     const auto &Bundle = CS.getOperandBundleAt(i);
2709     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2710 
2711     for (auto &Input : Bundle.Inputs)
2712       pushValueAndType(Input, InstID, Record);
2713 
2714     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2715     Record.clear();
2716   }
2717 }
2718 
2719 /// pushValue - Like pushValueAndType, but where the type of the value is
2720 /// omitted (perhaps it was already encoded in an earlier operand).
2721 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2722                                     SmallVectorImpl<unsigned> &Vals) {
2723   unsigned ValID = VE.getValueID(V);
2724   Vals.push_back(InstID - ValID);
2725 }
2726 
2727 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2728                                           SmallVectorImpl<uint64_t> &Vals) {
2729   unsigned ValID = VE.getValueID(V);
2730   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2731   emitSignedInt64(Vals, diff);
2732 }
2733 
2734 /// WriteInstruction - Emit an instruction to the specified stream.
2735 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2736                                            unsigned InstID,
2737                                            SmallVectorImpl<unsigned> &Vals) {
2738   unsigned Code = 0;
2739   unsigned AbbrevToUse = 0;
2740   VE.setInstructionID(&I);
2741   switch (I.getOpcode()) {
2742   default:
2743     if (Instruction::isCast(I.getOpcode())) {
2744       Code = bitc::FUNC_CODE_INST_CAST;
2745       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2746         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2747       Vals.push_back(VE.getTypeID(I.getType()));
2748       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2749     } else {
2750       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2751       Code = bitc::FUNC_CODE_INST_BINOP;
2752       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2753         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2754       pushValue(I.getOperand(1), InstID, Vals);
2755       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2756       uint64_t Flags = getOptimizationFlags(&I);
2757       if (Flags != 0) {
2758         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2759           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2760         Vals.push_back(Flags);
2761       }
2762     }
2763     break;
2764   case Instruction::FNeg: {
2765     Code = bitc::FUNC_CODE_INST_UNOP;
2766     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2767       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
2768     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
2769     uint64_t Flags = getOptimizationFlags(&I);
2770     if (Flags != 0) {
2771       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
2772         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
2773       Vals.push_back(Flags);
2774     }
2775     break;
2776   }
2777   case Instruction::GetElementPtr: {
2778     Code = bitc::FUNC_CODE_INST_GEP;
2779     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2780     auto &GEPInst = cast<GetElementPtrInst>(I);
2781     Vals.push_back(GEPInst.isInBounds());
2782     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2783     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2784       pushValueAndType(I.getOperand(i), InstID, Vals);
2785     break;
2786   }
2787   case Instruction::ExtractValue: {
2788     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2789     pushValueAndType(I.getOperand(0), InstID, Vals);
2790     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2791     Vals.append(EVI->idx_begin(), EVI->idx_end());
2792     break;
2793   }
2794   case Instruction::InsertValue: {
2795     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2796     pushValueAndType(I.getOperand(0), InstID, Vals);
2797     pushValueAndType(I.getOperand(1), InstID, Vals);
2798     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2799     Vals.append(IVI->idx_begin(), IVI->idx_end());
2800     break;
2801   }
2802   case Instruction::Select: {
2803     Code = bitc::FUNC_CODE_INST_VSELECT;
2804     pushValueAndType(I.getOperand(1), InstID, Vals);
2805     pushValue(I.getOperand(2), InstID, Vals);
2806     pushValueAndType(I.getOperand(0), InstID, Vals);
2807     uint64_t Flags = getOptimizationFlags(&I);
2808     if (Flags != 0)
2809       Vals.push_back(Flags);
2810     break;
2811   }
2812   case Instruction::ExtractElement:
2813     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2814     pushValueAndType(I.getOperand(0), InstID, Vals);
2815     pushValueAndType(I.getOperand(1), InstID, Vals);
2816     break;
2817   case Instruction::InsertElement:
2818     Code = bitc::FUNC_CODE_INST_INSERTELT;
2819     pushValueAndType(I.getOperand(0), InstID, Vals);
2820     pushValue(I.getOperand(1), InstID, Vals);
2821     pushValueAndType(I.getOperand(2), InstID, Vals);
2822     break;
2823   case Instruction::ShuffleVector:
2824     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2825     pushValueAndType(I.getOperand(0), InstID, Vals);
2826     pushValue(I.getOperand(1), InstID, Vals);
2827     pushValue(cast<ShuffleVectorInst>(I).getShuffleMaskForBitcode(), InstID,
2828               Vals);
2829     break;
2830   case Instruction::ICmp:
2831   case Instruction::FCmp: {
2832     // compare returning Int1Ty or vector of Int1Ty
2833     Code = bitc::FUNC_CODE_INST_CMP2;
2834     pushValueAndType(I.getOperand(0), InstID, Vals);
2835     pushValue(I.getOperand(1), InstID, Vals);
2836     Vals.push_back(cast<CmpInst>(I).getPredicate());
2837     uint64_t Flags = getOptimizationFlags(&I);
2838     if (Flags != 0)
2839       Vals.push_back(Flags);
2840     break;
2841   }
2842 
2843   case Instruction::Ret:
2844     {
2845       Code = bitc::FUNC_CODE_INST_RET;
2846       unsigned NumOperands = I.getNumOperands();
2847       if (NumOperands == 0)
2848         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2849       else if (NumOperands == 1) {
2850         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2851           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2852       } else {
2853         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2854           pushValueAndType(I.getOperand(i), InstID, Vals);
2855       }
2856     }
2857     break;
2858   case Instruction::Br:
2859     {
2860       Code = bitc::FUNC_CODE_INST_BR;
2861       const BranchInst &II = cast<BranchInst>(I);
2862       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2863       if (II.isConditional()) {
2864         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2865         pushValue(II.getCondition(), InstID, Vals);
2866       }
2867     }
2868     break;
2869   case Instruction::Switch:
2870     {
2871       Code = bitc::FUNC_CODE_INST_SWITCH;
2872       const SwitchInst &SI = cast<SwitchInst>(I);
2873       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2874       pushValue(SI.getCondition(), InstID, Vals);
2875       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2876       for (auto Case : SI.cases()) {
2877         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2878         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2879       }
2880     }
2881     break;
2882   case Instruction::IndirectBr:
2883     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2884     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2885     // Encode the address operand as relative, but not the basic blocks.
2886     pushValue(I.getOperand(0), InstID, Vals);
2887     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2888       Vals.push_back(VE.getValueID(I.getOperand(i)));
2889     break;
2890 
2891   case Instruction::Invoke: {
2892     const InvokeInst *II = cast<InvokeInst>(&I);
2893     const Value *Callee = II->getCalledOperand();
2894     FunctionType *FTy = II->getFunctionType();
2895 
2896     if (II->hasOperandBundles())
2897       writeOperandBundles(*II, InstID);
2898 
2899     Code = bitc::FUNC_CODE_INST_INVOKE;
2900 
2901     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
2902     Vals.push_back(II->getCallingConv() | 1 << 13);
2903     Vals.push_back(VE.getValueID(II->getNormalDest()));
2904     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2905     Vals.push_back(VE.getTypeID(FTy));
2906     pushValueAndType(Callee, InstID, Vals);
2907 
2908     // Emit value #'s for the fixed parameters.
2909     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2910       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2911 
2912     // Emit type/value pairs for varargs params.
2913     if (FTy->isVarArg()) {
2914       for (unsigned i = FTy->getNumParams(), e = II->getNumArgOperands();
2915            i != e; ++i)
2916         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2917     }
2918     break;
2919   }
2920   case Instruction::Resume:
2921     Code = bitc::FUNC_CODE_INST_RESUME;
2922     pushValueAndType(I.getOperand(0), InstID, Vals);
2923     break;
2924   case Instruction::CleanupRet: {
2925     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2926     const auto &CRI = cast<CleanupReturnInst>(I);
2927     pushValue(CRI.getCleanupPad(), InstID, Vals);
2928     if (CRI.hasUnwindDest())
2929       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2930     break;
2931   }
2932   case Instruction::CatchRet: {
2933     Code = bitc::FUNC_CODE_INST_CATCHRET;
2934     const auto &CRI = cast<CatchReturnInst>(I);
2935     pushValue(CRI.getCatchPad(), InstID, Vals);
2936     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2937     break;
2938   }
2939   case Instruction::CleanupPad:
2940   case Instruction::CatchPad: {
2941     const auto &FuncletPad = cast<FuncletPadInst>(I);
2942     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2943                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2944     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2945 
2946     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2947     Vals.push_back(NumArgOperands);
2948     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2949       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2950     break;
2951   }
2952   case Instruction::CatchSwitch: {
2953     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2954     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2955 
2956     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2957 
2958     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2959     Vals.push_back(NumHandlers);
2960     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2961       Vals.push_back(VE.getValueID(CatchPadBB));
2962 
2963     if (CatchSwitch.hasUnwindDest())
2964       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
2965     break;
2966   }
2967   case Instruction::CallBr: {
2968     const CallBrInst *CBI = cast<CallBrInst>(&I);
2969     const Value *Callee = CBI->getCalledOperand();
2970     FunctionType *FTy = CBI->getFunctionType();
2971 
2972     if (CBI->hasOperandBundles())
2973       writeOperandBundles(*CBI, InstID);
2974 
2975     Code = bitc::FUNC_CODE_INST_CALLBR;
2976 
2977     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
2978 
2979     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
2980                    1 << bitc::CALL_EXPLICIT_TYPE);
2981 
2982     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
2983     Vals.push_back(CBI->getNumIndirectDests());
2984     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
2985       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
2986 
2987     Vals.push_back(VE.getTypeID(FTy));
2988     pushValueAndType(Callee, InstID, Vals);
2989 
2990     // Emit value #'s for the fixed parameters.
2991     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2992       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2993 
2994     // Emit type/value pairs for varargs params.
2995     if (FTy->isVarArg()) {
2996       for (unsigned i = FTy->getNumParams(), e = CBI->getNumArgOperands();
2997            i != e; ++i)
2998         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2999     }
3000     break;
3001   }
3002   case Instruction::Unreachable:
3003     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
3004     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
3005     break;
3006 
3007   case Instruction::PHI: {
3008     const PHINode &PN = cast<PHINode>(I);
3009     Code = bitc::FUNC_CODE_INST_PHI;
3010     // With the newer instruction encoding, forward references could give
3011     // negative valued IDs.  This is most common for PHIs, so we use
3012     // signed VBRs.
3013     SmallVector<uint64_t, 128> Vals64;
3014     Vals64.push_back(VE.getTypeID(PN.getType()));
3015     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
3016       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
3017       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
3018     }
3019 
3020     uint64_t Flags = getOptimizationFlags(&I);
3021     if (Flags != 0)
3022       Vals64.push_back(Flags);
3023 
3024     // Emit a Vals64 vector and exit.
3025     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
3026     Vals64.clear();
3027     return;
3028   }
3029 
3030   case Instruction::LandingPad: {
3031     const LandingPadInst &LP = cast<LandingPadInst>(I);
3032     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
3033     Vals.push_back(VE.getTypeID(LP.getType()));
3034     Vals.push_back(LP.isCleanup());
3035     Vals.push_back(LP.getNumClauses());
3036     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
3037       if (LP.isCatch(I))
3038         Vals.push_back(LandingPadInst::Catch);
3039       else
3040         Vals.push_back(LandingPadInst::Filter);
3041       pushValueAndType(LP.getClause(I), InstID, Vals);
3042     }
3043     break;
3044   }
3045 
3046   case Instruction::Alloca: {
3047     Code = bitc::FUNC_CODE_INST_ALLOCA;
3048     const AllocaInst &AI = cast<AllocaInst>(I);
3049     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
3050     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
3051     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
3052     using APV = AllocaPackedValues;
3053     unsigned Record = 0;
3054     Bitfield::set<APV::Align>(Record, getEncodedAlign(AI.getAlign()));
3055     Bitfield::set<APV::UsedWithInAlloca>(Record, AI.isUsedWithInAlloca());
3056     Bitfield::set<APV::ExplicitType>(Record, true);
3057     Bitfield::set<APV::SwiftError>(Record, AI.isSwiftError());
3058     Vals.push_back(Record);
3059     break;
3060   }
3061 
3062   case Instruction::Load:
3063     if (cast<LoadInst>(I).isAtomic()) {
3064       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
3065       pushValueAndType(I.getOperand(0), InstID, Vals);
3066     } else {
3067       Code = bitc::FUNC_CODE_INST_LOAD;
3068       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
3069         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
3070     }
3071     Vals.push_back(VE.getTypeID(I.getType()));
3072     Vals.push_back(getEncodedAlign(cast<LoadInst>(I).getAlign()));
3073     Vals.push_back(cast<LoadInst>(I).isVolatile());
3074     if (cast<LoadInst>(I).isAtomic()) {
3075       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
3076       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
3077     }
3078     break;
3079   case Instruction::Store:
3080     if (cast<StoreInst>(I).isAtomic())
3081       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
3082     else
3083       Code = bitc::FUNC_CODE_INST_STORE;
3084     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
3085     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
3086     Vals.push_back(getEncodedAlign(cast<StoreInst>(I).getAlign()));
3087     Vals.push_back(cast<StoreInst>(I).isVolatile());
3088     if (cast<StoreInst>(I).isAtomic()) {
3089       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
3090       Vals.push_back(
3091           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
3092     }
3093     break;
3094   case Instruction::AtomicCmpXchg:
3095     Code = bitc::FUNC_CODE_INST_CMPXCHG;
3096     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3097     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
3098     pushValue(I.getOperand(2), InstID, Vals);        // newval.
3099     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
3100     Vals.push_back(
3101         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
3102     Vals.push_back(
3103         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
3104     Vals.push_back(
3105         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
3106     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
3107     Vals.push_back(getEncodedAlign(cast<AtomicCmpXchgInst>(I).getAlign()));
3108     break;
3109   case Instruction::AtomicRMW:
3110     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
3111     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3112     pushValueAndType(I.getOperand(1), InstID, Vals); // valty + val
3113     Vals.push_back(
3114         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
3115     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
3116     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
3117     Vals.push_back(
3118         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
3119     Vals.push_back(getEncodedAlign(cast<AtomicRMWInst>(I).getAlign()));
3120     break;
3121   case Instruction::Fence:
3122     Code = bitc::FUNC_CODE_INST_FENCE;
3123     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
3124     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
3125     break;
3126   case Instruction::Call: {
3127     const CallInst &CI = cast<CallInst>(I);
3128     FunctionType *FTy = CI.getFunctionType();
3129 
3130     if (CI.hasOperandBundles())
3131       writeOperandBundles(CI, InstID);
3132 
3133     Code = bitc::FUNC_CODE_INST_CALL;
3134 
3135     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
3136 
3137     unsigned Flags = getOptimizationFlags(&I);
3138     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
3139                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
3140                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
3141                    1 << bitc::CALL_EXPLICIT_TYPE |
3142                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
3143                    unsigned(Flags != 0) << bitc::CALL_FMF);
3144     if (Flags != 0)
3145       Vals.push_back(Flags);
3146 
3147     Vals.push_back(VE.getTypeID(FTy));
3148     pushValueAndType(CI.getCalledOperand(), InstID, Vals); // Callee
3149 
3150     // Emit value #'s for the fixed parameters.
3151     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3152       // Check for labels (can happen with asm labels).
3153       if (FTy->getParamType(i)->isLabelTy())
3154         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3155       else
3156         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3157     }
3158 
3159     // Emit type/value pairs for varargs params.
3160     if (FTy->isVarArg()) {
3161       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
3162            i != e; ++i)
3163         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3164     }
3165     break;
3166   }
3167   case Instruction::VAArg:
3168     Code = bitc::FUNC_CODE_INST_VAARG;
3169     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3170     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3171     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3172     break;
3173   case Instruction::Freeze:
3174     Code = bitc::FUNC_CODE_INST_FREEZE;
3175     pushValueAndType(I.getOperand(0), InstID, Vals);
3176     break;
3177   }
3178 
3179   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3180   Vals.clear();
3181 }
3182 
3183 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3184 /// to allow clients to efficiently find the function body.
3185 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3186   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3187   // Get the offset of the VST we are writing, and backpatch it into
3188   // the VST forward declaration record.
3189   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3190   // The BitcodeStartBit was the stream offset of the identification block.
3191   VSTOffset -= bitcodeStartBit();
3192   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3193   // Note that we add 1 here because the offset is relative to one word
3194   // before the start of the identification block, which was historically
3195   // always the start of the regular bitcode header.
3196   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3197 
3198   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3199 
3200   auto Abbv = std::make_shared<BitCodeAbbrev>();
3201   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3202   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3203   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3204   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3205 
3206   for (const Function &F : M) {
3207     uint64_t Record[2];
3208 
3209     if (F.isDeclaration())
3210       continue;
3211 
3212     Record[0] = VE.getValueID(&F);
3213 
3214     // Save the word offset of the function (from the start of the
3215     // actual bitcode written to the stream).
3216     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3217     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3218     // Note that we add 1 here because the offset is relative to one word
3219     // before the start of the identification block, which was historically
3220     // always the start of the regular bitcode header.
3221     Record[1] = BitcodeIndex / 32 + 1;
3222 
3223     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3224   }
3225 
3226   Stream.ExitBlock();
3227 }
3228 
3229 /// Emit names for arguments, instructions and basic blocks in a function.
3230 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3231     const ValueSymbolTable &VST) {
3232   if (VST.empty())
3233     return;
3234 
3235   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3236 
3237   // FIXME: Set up the abbrev, we know how many values there are!
3238   // FIXME: We know if the type names can use 7-bit ascii.
3239   SmallVector<uint64_t, 64> NameVals;
3240 
3241   for (const ValueName &Name : VST) {
3242     // Figure out the encoding to use for the name.
3243     StringEncoding Bits = getStringEncoding(Name.getKey());
3244 
3245     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3246     NameVals.push_back(VE.getValueID(Name.getValue()));
3247 
3248     // VST_CODE_ENTRY:   [valueid, namechar x N]
3249     // VST_CODE_BBENTRY: [bbid, namechar x N]
3250     unsigned Code;
3251     if (isa<BasicBlock>(Name.getValue())) {
3252       Code = bitc::VST_CODE_BBENTRY;
3253       if (Bits == SE_Char6)
3254         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3255     } else {
3256       Code = bitc::VST_CODE_ENTRY;
3257       if (Bits == SE_Char6)
3258         AbbrevToUse = VST_ENTRY_6_ABBREV;
3259       else if (Bits == SE_Fixed7)
3260         AbbrevToUse = VST_ENTRY_7_ABBREV;
3261     }
3262 
3263     for (const auto P : Name.getKey())
3264       NameVals.push_back((unsigned char)P);
3265 
3266     // Emit the finished record.
3267     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3268     NameVals.clear();
3269   }
3270 
3271   Stream.ExitBlock();
3272 }
3273 
3274 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3275   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3276   unsigned Code;
3277   if (isa<BasicBlock>(Order.V))
3278     Code = bitc::USELIST_CODE_BB;
3279   else
3280     Code = bitc::USELIST_CODE_DEFAULT;
3281 
3282   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3283   Record.push_back(VE.getValueID(Order.V));
3284   Stream.EmitRecord(Code, Record);
3285 }
3286 
3287 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3288   assert(VE.shouldPreserveUseListOrder() &&
3289          "Expected to be preserving use-list order");
3290 
3291   auto hasMore = [&]() {
3292     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3293   };
3294   if (!hasMore())
3295     // Nothing to do.
3296     return;
3297 
3298   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3299   while (hasMore()) {
3300     writeUseList(std::move(VE.UseListOrders.back()));
3301     VE.UseListOrders.pop_back();
3302   }
3303   Stream.ExitBlock();
3304 }
3305 
3306 /// Emit a function body to the module stream.
3307 void ModuleBitcodeWriter::writeFunction(
3308     const Function &F,
3309     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3310   // Save the bitcode index of the start of this function block for recording
3311   // in the VST.
3312   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3313 
3314   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3315   VE.incorporateFunction(F);
3316 
3317   SmallVector<unsigned, 64> Vals;
3318 
3319   // Emit the number of basic blocks, so the reader can create them ahead of
3320   // time.
3321   Vals.push_back(VE.getBasicBlocks().size());
3322   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3323   Vals.clear();
3324 
3325   // If there are function-local constants, emit them now.
3326   unsigned CstStart, CstEnd;
3327   VE.getFunctionConstantRange(CstStart, CstEnd);
3328   writeConstants(CstStart, CstEnd, false);
3329 
3330   // If there is function-local metadata, emit it now.
3331   writeFunctionMetadata(F);
3332 
3333   // Keep a running idea of what the instruction ID is.
3334   unsigned InstID = CstEnd;
3335 
3336   bool NeedsMetadataAttachment = F.hasMetadata();
3337 
3338   DILocation *LastDL = nullptr;
3339   // Finally, emit all the instructions, in order.
3340   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
3341     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
3342          I != E; ++I) {
3343       writeInstruction(*I, InstID, Vals);
3344 
3345       if (!I->getType()->isVoidTy())
3346         ++InstID;
3347 
3348       // If the instruction has metadata, write a metadata attachment later.
3349       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
3350 
3351       // If the instruction has a debug location, emit it.
3352       DILocation *DL = I->getDebugLoc();
3353       if (!DL)
3354         continue;
3355 
3356       if (DL == LastDL) {
3357         // Just repeat the same debug loc as last time.
3358         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3359         continue;
3360       }
3361 
3362       Vals.push_back(DL->getLine());
3363       Vals.push_back(DL->getColumn());
3364       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3365       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3366       Vals.push_back(DL->isImplicitCode());
3367       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3368       Vals.clear();
3369 
3370       LastDL = DL;
3371     }
3372 
3373   // Emit names for all the instructions etc.
3374   if (auto *Symtab = F.getValueSymbolTable())
3375     writeFunctionLevelValueSymbolTable(*Symtab);
3376 
3377   if (NeedsMetadataAttachment)
3378     writeFunctionMetadataAttachment(F);
3379   if (VE.shouldPreserveUseListOrder())
3380     writeUseListBlock(&F);
3381   VE.purgeFunction();
3382   Stream.ExitBlock();
3383 }
3384 
3385 // Emit blockinfo, which defines the standard abbreviations etc.
3386 void ModuleBitcodeWriter::writeBlockInfo() {
3387   // We only want to emit block info records for blocks that have multiple
3388   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3389   // Other blocks can define their abbrevs inline.
3390   Stream.EnterBlockInfoBlock();
3391 
3392   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3393     auto Abbv = std::make_shared<BitCodeAbbrev>();
3394     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3395     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3396     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3397     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3398     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3399         VST_ENTRY_8_ABBREV)
3400       llvm_unreachable("Unexpected abbrev ordering!");
3401   }
3402 
3403   { // 7-bit fixed width VST_CODE_ENTRY strings.
3404     auto Abbv = std::make_shared<BitCodeAbbrev>();
3405     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3406     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3407     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3408     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3409     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3410         VST_ENTRY_7_ABBREV)
3411       llvm_unreachable("Unexpected abbrev ordering!");
3412   }
3413   { // 6-bit char6 VST_CODE_ENTRY strings.
3414     auto Abbv = std::make_shared<BitCodeAbbrev>();
3415     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3416     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3417     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3418     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3419     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3420         VST_ENTRY_6_ABBREV)
3421       llvm_unreachable("Unexpected abbrev ordering!");
3422   }
3423   { // 6-bit char6 VST_CODE_BBENTRY strings.
3424     auto Abbv = std::make_shared<BitCodeAbbrev>();
3425     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3426     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3427     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3428     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3429     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3430         VST_BBENTRY_6_ABBREV)
3431       llvm_unreachable("Unexpected abbrev ordering!");
3432   }
3433 
3434   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3435     auto Abbv = std::make_shared<BitCodeAbbrev>();
3436     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3437     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3438                               VE.computeBitsRequiredForTypeIndicies()));
3439     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3440         CONSTANTS_SETTYPE_ABBREV)
3441       llvm_unreachable("Unexpected abbrev ordering!");
3442   }
3443 
3444   { // INTEGER abbrev for CONSTANTS_BLOCK.
3445     auto Abbv = std::make_shared<BitCodeAbbrev>();
3446     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3447     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3448     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3449         CONSTANTS_INTEGER_ABBREV)
3450       llvm_unreachable("Unexpected abbrev ordering!");
3451   }
3452 
3453   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3454     auto Abbv = std::make_shared<BitCodeAbbrev>();
3455     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3456     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3457     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3458                               VE.computeBitsRequiredForTypeIndicies()));
3459     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3460 
3461     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3462         CONSTANTS_CE_CAST_Abbrev)
3463       llvm_unreachable("Unexpected abbrev ordering!");
3464   }
3465   { // NULL abbrev for CONSTANTS_BLOCK.
3466     auto Abbv = std::make_shared<BitCodeAbbrev>();
3467     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3468     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3469         CONSTANTS_NULL_Abbrev)
3470       llvm_unreachable("Unexpected abbrev ordering!");
3471   }
3472 
3473   // FIXME: This should only use space for first class types!
3474 
3475   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3476     auto Abbv = std::make_shared<BitCodeAbbrev>();
3477     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3478     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3479     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3480                               VE.computeBitsRequiredForTypeIndicies()));
3481     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3482     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3483     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3484         FUNCTION_INST_LOAD_ABBREV)
3485       llvm_unreachable("Unexpected abbrev ordering!");
3486   }
3487   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3488     auto Abbv = std::make_shared<BitCodeAbbrev>();
3489     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3490     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3491     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3492     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3493         FUNCTION_INST_UNOP_ABBREV)
3494       llvm_unreachable("Unexpected abbrev ordering!");
3495   }
3496   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3497     auto Abbv = std::make_shared<BitCodeAbbrev>();
3498     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3499     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3500     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3501     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3502     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3503         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3504       llvm_unreachable("Unexpected abbrev ordering!");
3505   }
3506   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3507     auto Abbv = std::make_shared<BitCodeAbbrev>();
3508     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3509     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3510     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3511     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3512     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3513         FUNCTION_INST_BINOP_ABBREV)
3514       llvm_unreachable("Unexpected abbrev ordering!");
3515   }
3516   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3517     auto Abbv = std::make_shared<BitCodeAbbrev>();
3518     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3519     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3520     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3521     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3522     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3523     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3524         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3525       llvm_unreachable("Unexpected abbrev ordering!");
3526   }
3527   { // INST_CAST abbrev for FUNCTION_BLOCK.
3528     auto Abbv = std::make_shared<BitCodeAbbrev>();
3529     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3530     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3531     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3532                               VE.computeBitsRequiredForTypeIndicies()));
3533     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3534     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3535         FUNCTION_INST_CAST_ABBREV)
3536       llvm_unreachable("Unexpected abbrev ordering!");
3537   }
3538 
3539   { // INST_RET abbrev for FUNCTION_BLOCK.
3540     auto Abbv = std::make_shared<BitCodeAbbrev>();
3541     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3542     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3543         FUNCTION_INST_RET_VOID_ABBREV)
3544       llvm_unreachable("Unexpected abbrev ordering!");
3545   }
3546   { // INST_RET abbrev for FUNCTION_BLOCK.
3547     auto Abbv = std::make_shared<BitCodeAbbrev>();
3548     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3549     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3550     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3551         FUNCTION_INST_RET_VAL_ABBREV)
3552       llvm_unreachable("Unexpected abbrev ordering!");
3553   }
3554   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3555     auto Abbv = std::make_shared<BitCodeAbbrev>();
3556     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3557     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3558         FUNCTION_INST_UNREACHABLE_ABBREV)
3559       llvm_unreachable("Unexpected abbrev ordering!");
3560   }
3561   {
3562     auto Abbv = std::make_shared<BitCodeAbbrev>();
3563     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3564     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3565     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3566                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3567     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3568     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3569     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3570         FUNCTION_INST_GEP_ABBREV)
3571       llvm_unreachable("Unexpected abbrev ordering!");
3572   }
3573 
3574   Stream.ExitBlock();
3575 }
3576 
3577 /// Write the module path strings, currently only used when generating
3578 /// a combined index file.
3579 void IndexBitcodeWriter::writeModStrings() {
3580   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3581 
3582   // TODO: See which abbrev sizes we actually need to emit
3583 
3584   // 8-bit fixed-width MST_ENTRY strings.
3585   auto Abbv = std::make_shared<BitCodeAbbrev>();
3586   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3587   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3588   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3589   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3590   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3591 
3592   // 7-bit fixed width MST_ENTRY strings.
3593   Abbv = std::make_shared<BitCodeAbbrev>();
3594   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3595   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3596   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3597   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3598   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3599 
3600   // 6-bit char6 MST_ENTRY strings.
3601   Abbv = std::make_shared<BitCodeAbbrev>();
3602   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3603   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3604   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3605   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3606   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3607 
3608   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3609   Abbv = std::make_shared<BitCodeAbbrev>();
3610   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3611   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3612   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3613   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3614   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3615   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3616   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3617 
3618   SmallVector<unsigned, 64> Vals;
3619   forEachModule(
3620       [&](const StringMapEntry<std::pair<uint64_t, ModuleHash>> &MPSE) {
3621         StringRef Key = MPSE.getKey();
3622         const auto &Value = MPSE.getValue();
3623         StringEncoding Bits = getStringEncoding(Key);
3624         unsigned AbbrevToUse = Abbrev8Bit;
3625         if (Bits == SE_Char6)
3626           AbbrevToUse = Abbrev6Bit;
3627         else if (Bits == SE_Fixed7)
3628           AbbrevToUse = Abbrev7Bit;
3629 
3630         Vals.push_back(Value.first);
3631         Vals.append(Key.begin(), Key.end());
3632 
3633         // Emit the finished record.
3634         Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3635 
3636         // Emit an optional hash for the module now
3637         const auto &Hash = Value.second;
3638         if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3639           Vals.assign(Hash.begin(), Hash.end());
3640           // Emit the hash record.
3641           Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3642         }
3643 
3644         Vals.clear();
3645       });
3646   Stream.ExitBlock();
3647 }
3648 
3649 /// Write the function type metadata related records that need to appear before
3650 /// a function summary entry (whether per-module or combined).
3651 template <typename Fn>
3652 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
3653                                              FunctionSummary *FS,
3654                                              Fn GetValueID) {
3655   if (!FS->type_tests().empty())
3656     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3657 
3658   SmallVector<uint64_t, 64> Record;
3659 
3660   auto WriteVFuncIdVec = [&](uint64_t Ty,
3661                              ArrayRef<FunctionSummary::VFuncId> VFs) {
3662     if (VFs.empty())
3663       return;
3664     Record.clear();
3665     for (auto &VF : VFs) {
3666       Record.push_back(VF.GUID);
3667       Record.push_back(VF.Offset);
3668     }
3669     Stream.EmitRecord(Ty, Record);
3670   };
3671 
3672   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
3673                   FS->type_test_assume_vcalls());
3674   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
3675                   FS->type_checked_load_vcalls());
3676 
3677   auto WriteConstVCallVec = [&](uint64_t Ty,
3678                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
3679     for (auto &VC : VCs) {
3680       Record.clear();
3681       Record.push_back(VC.VFunc.GUID);
3682       Record.push_back(VC.VFunc.Offset);
3683       llvm::append_range(Record, VC.Args);
3684       Stream.EmitRecord(Ty, Record);
3685     }
3686   };
3687 
3688   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
3689                      FS->type_test_assume_const_vcalls());
3690   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
3691                      FS->type_checked_load_const_vcalls());
3692 
3693   auto WriteRange = [&](ConstantRange Range) {
3694     Range = Range.sextOrTrunc(FunctionSummary::ParamAccess::RangeWidth);
3695     assert(Range.getLower().getNumWords() == 1);
3696     assert(Range.getUpper().getNumWords() == 1);
3697     emitSignedInt64(Record, *Range.getLower().getRawData());
3698     emitSignedInt64(Record, *Range.getUpper().getRawData());
3699   };
3700 
3701   if (!FS->paramAccesses().empty()) {
3702     Record.clear();
3703     for (auto &Arg : FS->paramAccesses()) {
3704       size_t UndoSize = Record.size();
3705       Record.push_back(Arg.ParamNo);
3706       WriteRange(Arg.Use);
3707       Record.push_back(Arg.Calls.size());
3708       for (auto &Call : Arg.Calls) {
3709         Record.push_back(Call.ParamNo);
3710         Optional<unsigned> ValueID = GetValueID(Call.Callee);
3711         if (!ValueID) {
3712           // If ValueID is unknown we can't drop just this call, we must drop
3713           // entire parameter.
3714           Record.resize(UndoSize);
3715           break;
3716         }
3717         Record.push_back(*ValueID);
3718         WriteRange(Call.Offsets);
3719       }
3720     }
3721     if (!Record.empty())
3722       Stream.EmitRecord(bitc::FS_PARAM_ACCESS, Record);
3723   }
3724 }
3725 
3726 /// Collect type IDs from type tests used by function.
3727 static void
3728 getReferencedTypeIds(FunctionSummary *FS,
3729                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
3730   if (!FS->type_tests().empty())
3731     for (auto &TT : FS->type_tests())
3732       ReferencedTypeIds.insert(TT);
3733 
3734   auto GetReferencedTypesFromVFuncIdVec =
3735       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
3736         for (auto &VF : VFs)
3737           ReferencedTypeIds.insert(VF.GUID);
3738       };
3739 
3740   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
3741   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
3742 
3743   auto GetReferencedTypesFromConstVCallVec =
3744       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
3745         for (auto &VC : VCs)
3746           ReferencedTypeIds.insert(VC.VFunc.GUID);
3747       };
3748 
3749   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
3750   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
3751 }
3752 
3753 static void writeWholeProgramDevirtResolutionByArg(
3754     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
3755     const WholeProgramDevirtResolution::ByArg &ByArg) {
3756   NameVals.push_back(args.size());
3757   llvm::append_range(NameVals, args);
3758 
3759   NameVals.push_back(ByArg.TheKind);
3760   NameVals.push_back(ByArg.Info);
3761   NameVals.push_back(ByArg.Byte);
3762   NameVals.push_back(ByArg.Bit);
3763 }
3764 
3765 static void writeWholeProgramDevirtResolution(
3766     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3767     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
3768   NameVals.push_back(Id);
3769 
3770   NameVals.push_back(Wpd.TheKind);
3771   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
3772   NameVals.push_back(Wpd.SingleImplName.size());
3773 
3774   NameVals.push_back(Wpd.ResByArg.size());
3775   for (auto &A : Wpd.ResByArg)
3776     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
3777 }
3778 
3779 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
3780                                      StringTableBuilder &StrtabBuilder,
3781                                      const std::string &Id,
3782                                      const TypeIdSummary &Summary) {
3783   NameVals.push_back(StrtabBuilder.add(Id));
3784   NameVals.push_back(Id.size());
3785 
3786   NameVals.push_back(Summary.TTRes.TheKind);
3787   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
3788   NameVals.push_back(Summary.TTRes.AlignLog2);
3789   NameVals.push_back(Summary.TTRes.SizeM1);
3790   NameVals.push_back(Summary.TTRes.BitMask);
3791   NameVals.push_back(Summary.TTRes.InlineBits);
3792 
3793   for (auto &W : Summary.WPDRes)
3794     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
3795                                       W.second);
3796 }
3797 
3798 static void writeTypeIdCompatibleVtableSummaryRecord(
3799     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3800     const std::string &Id, const TypeIdCompatibleVtableInfo &Summary,
3801     ValueEnumerator &VE) {
3802   NameVals.push_back(StrtabBuilder.add(Id));
3803   NameVals.push_back(Id.size());
3804 
3805   for (auto &P : Summary) {
3806     NameVals.push_back(P.AddressPointOffset);
3807     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
3808   }
3809 }
3810 
3811 // Helper to emit a single function summary record.
3812 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
3813     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3814     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3815     const Function &F) {
3816   NameVals.push_back(ValueID);
3817 
3818   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3819 
3820   writeFunctionTypeMetadataRecords(
3821       Stream, FS, [&](const ValueInfo &VI) -> Optional<unsigned> {
3822         return {VE.getValueID(VI.getValue())};
3823       });
3824 
3825   auto SpecialRefCnts = FS->specialRefCounts();
3826   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3827   NameVals.push_back(FS->instCount());
3828   NameVals.push_back(getEncodedFFlags(FS->fflags()));
3829   NameVals.push_back(FS->refs().size());
3830   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
3831   NameVals.push_back(SpecialRefCnts.second); // worefcnt
3832 
3833   for (auto &RI : FS->refs())
3834     NameVals.push_back(VE.getValueID(RI.getValue()));
3835 
3836   bool HasProfileData =
3837       F.hasProfileData() || ForceSummaryEdgesCold != FunctionSummary::FSHT_None;
3838   for (auto &ECI : FS->calls()) {
3839     NameVals.push_back(getValueId(ECI.first));
3840     if (HasProfileData)
3841       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
3842     else if (WriteRelBFToSummary)
3843       NameVals.push_back(ECI.second.RelBlockFreq);
3844   }
3845 
3846   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3847   unsigned Code =
3848       (HasProfileData ? bitc::FS_PERMODULE_PROFILE
3849                       : (WriteRelBFToSummary ? bitc::FS_PERMODULE_RELBF
3850                                              : bitc::FS_PERMODULE));
3851 
3852   // Emit the finished record.
3853   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3854   NameVals.clear();
3855 }
3856 
3857 // Collect the global value references in the given variable's initializer,
3858 // and emit them in a summary record.
3859 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
3860     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3861     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
3862   auto VI = Index->getValueInfo(V.getGUID());
3863   if (!VI || VI.getSummaryList().empty()) {
3864     // Only declarations should not have a summary (a declaration might however
3865     // have a summary if the def was in module level asm).
3866     assert(V.isDeclaration());
3867     return;
3868   }
3869   auto *Summary = VI.getSummaryList()[0].get();
3870   NameVals.push_back(VE.getValueID(&V));
3871   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
3872   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3873   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
3874 
3875   auto VTableFuncs = VS->vTableFuncs();
3876   if (!VTableFuncs.empty())
3877     NameVals.push_back(VS->refs().size());
3878 
3879   unsigned SizeBeforeRefs = NameVals.size();
3880   for (auto &RI : VS->refs())
3881     NameVals.push_back(VE.getValueID(RI.getValue()));
3882   // Sort the refs for determinism output, the vector returned by FS->refs() has
3883   // been initialized from a DenseSet.
3884   llvm::sort(drop_begin(NameVals, SizeBeforeRefs));
3885 
3886   if (VTableFuncs.empty())
3887     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3888                       FSModRefsAbbrev);
3889   else {
3890     // VTableFuncs pairs should already be sorted by offset.
3891     for (auto &P : VTableFuncs) {
3892       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
3893       NameVals.push_back(P.VTableOffset);
3894     }
3895 
3896     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
3897                       FSModVTableRefsAbbrev);
3898   }
3899   NameVals.clear();
3900 }
3901 
3902 /// Emit the per-module summary section alongside the rest of
3903 /// the module's bitcode.
3904 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
3905   // By default we compile with ThinLTO if the module has a summary, but the
3906   // client can request full LTO with a module flag.
3907   bool IsThinLTO = true;
3908   if (auto *MD =
3909           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
3910     IsThinLTO = MD->getZExtValue();
3911   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
3912                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
3913                        4);
3914 
3915   Stream.EmitRecord(
3916       bitc::FS_VERSION,
3917       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
3918 
3919   // Write the index flags.
3920   uint64_t Flags = 0;
3921   // Bits 1-3 are set only in the combined index, skip them.
3922   if (Index->enableSplitLTOUnit())
3923     Flags |= 0x8;
3924   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
3925 
3926   if (Index->begin() == Index->end()) {
3927     Stream.ExitBlock();
3928     return;
3929   }
3930 
3931   for (const auto &GVI : valueIds()) {
3932     Stream.EmitRecord(bitc::FS_VALUE_GUID,
3933                       ArrayRef<uint64_t>{GVI.second, GVI.first});
3934   }
3935 
3936   // Abbrev for FS_PERMODULE_PROFILE.
3937   auto Abbv = std::make_shared<BitCodeAbbrev>();
3938   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
3939   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3940   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3941   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3942   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3943   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3944   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3945   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3946   // numrefs x valueid, n x (valueid, hotness)
3947   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3948   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3949   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3950 
3951   // Abbrev for FS_PERMODULE or FS_PERMODULE_RELBF.
3952   Abbv = std::make_shared<BitCodeAbbrev>();
3953   if (WriteRelBFToSummary)
3954     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
3955   else
3956     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
3957   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3958   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3959   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3960   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3961   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3962   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3963   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3964   // numrefs x valueid, n x (valueid [, rel_block_freq])
3965   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3966   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3967   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3968 
3969   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
3970   Abbv = std::make_shared<BitCodeAbbrev>();
3971   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
3972   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3973   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3974   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
3975   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3976   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3977 
3978   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
3979   Abbv = std::make_shared<BitCodeAbbrev>();
3980   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
3981   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3982   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3983   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
3984   // numrefs x valueid, n x (valueid , offset)
3985   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3986   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3987   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3988 
3989   // Abbrev for FS_ALIAS.
3990   Abbv = std::make_shared<BitCodeAbbrev>();
3991   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
3992   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3993   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3994   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3995   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3996 
3997   // Abbrev for FS_TYPE_ID_METADATA
3998   Abbv = std::make_shared<BitCodeAbbrev>();
3999   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
4000   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
4001   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
4002   // n x (valueid , offset)
4003   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4004   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4005   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4006 
4007   SmallVector<uint64_t, 64> NameVals;
4008   // Iterate over the list of functions instead of the Index to
4009   // ensure the ordering is stable.
4010   for (const Function &F : M) {
4011     // Summary emission does not support anonymous functions, they have to
4012     // renamed using the anonymous function renaming pass.
4013     if (!F.hasName())
4014       report_fatal_error("Unexpected anonymous function when writing summary");
4015 
4016     ValueInfo VI = Index->getValueInfo(F.getGUID());
4017     if (!VI || VI.getSummaryList().empty()) {
4018       // Only declarations should not have a summary (a declaration might
4019       // however have a summary if the def was in module level asm).
4020       assert(F.isDeclaration());
4021       continue;
4022     }
4023     auto *Summary = VI.getSummaryList()[0].get();
4024     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
4025                                         FSCallsAbbrev, FSCallsProfileAbbrev, F);
4026   }
4027 
4028   // Capture references from GlobalVariable initializers, which are outside
4029   // of a function scope.
4030   for (const GlobalVariable &G : M.globals())
4031     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
4032                                FSModVTableRefsAbbrev);
4033 
4034   for (const GlobalAlias &A : M.aliases()) {
4035     auto *Aliasee = A.getBaseObject();
4036     if (!Aliasee->hasName())
4037       // Nameless function don't have an entry in the summary, skip it.
4038       continue;
4039     auto AliasId = VE.getValueID(&A);
4040     auto AliaseeId = VE.getValueID(Aliasee);
4041     NameVals.push_back(AliasId);
4042     auto *Summary = Index->getGlobalValueSummary(A);
4043     AliasSummary *AS = cast<AliasSummary>(Summary);
4044     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4045     NameVals.push_back(AliaseeId);
4046     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
4047     NameVals.clear();
4048   }
4049 
4050   for (auto &S : Index->typeIdCompatibleVtableMap()) {
4051     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
4052                                              S.second, VE);
4053     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
4054                       TypeIdCompatibleVtableAbbrev);
4055     NameVals.clear();
4056   }
4057 
4058   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4059                     ArrayRef<uint64_t>{Index->getBlockCount()});
4060 
4061   Stream.ExitBlock();
4062 }
4063 
4064 /// Emit the combined summary section into the combined index file.
4065 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
4066   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
4067   Stream.EmitRecord(
4068       bitc::FS_VERSION,
4069       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4070 
4071   // Write the index flags.
4072   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Index.getFlags()});
4073 
4074   for (const auto &GVI : valueIds()) {
4075     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4076                       ArrayRef<uint64_t>{GVI.second, GVI.first});
4077   }
4078 
4079   // Abbrev for FS_COMBINED.
4080   auto Abbv = std::make_shared<BitCodeAbbrev>();
4081   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
4082   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4083   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4084   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4085   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4086   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4087   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4088   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4089   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4090   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4091   // numrefs x valueid, n x (valueid)
4092   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4093   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4094   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4095 
4096   // Abbrev for FS_COMBINED_PROFILE.
4097   Abbv = std::make_shared<BitCodeAbbrev>();
4098   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
4099   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4100   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4101   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4102   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4103   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4104   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4105   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4106   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4107   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4108   // numrefs x valueid, n x (valueid, hotness)
4109   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4110   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4111   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4112 
4113   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
4114   Abbv = std::make_shared<BitCodeAbbrev>();
4115   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
4116   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4117   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4118   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4119   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
4120   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4121   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4122 
4123   // Abbrev for FS_COMBINED_ALIAS.
4124   Abbv = std::make_shared<BitCodeAbbrev>();
4125   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
4126   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4127   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4128   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4129   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4130   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4131 
4132   // The aliases are emitted as a post-pass, and will point to the value
4133   // id of the aliasee. Save them in a vector for post-processing.
4134   SmallVector<AliasSummary *, 64> Aliases;
4135 
4136   // Save the value id for each summary for alias emission.
4137   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
4138 
4139   SmallVector<uint64_t, 64> NameVals;
4140 
4141   // Set that will be populated during call to writeFunctionTypeMetadataRecords
4142   // with the type ids referenced by this index file.
4143   std::set<GlobalValue::GUID> ReferencedTypeIds;
4144 
4145   // For local linkage, we also emit the original name separately
4146   // immediately after the record.
4147   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
4148     if (!GlobalValue::isLocalLinkage(S.linkage()))
4149       return;
4150     NameVals.push_back(S.getOriginalName());
4151     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
4152     NameVals.clear();
4153   };
4154 
4155   std::set<GlobalValue::GUID> DefOrUseGUIDs;
4156   forEachSummary([&](GVInfo I, bool IsAliasee) {
4157     GlobalValueSummary *S = I.second;
4158     assert(S);
4159     DefOrUseGUIDs.insert(I.first);
4160     for (const ValueInfo &VI : S->refs())
4161       DefOrUseGUIDs.insert(VI.getGUID());
4162 
4163     auto ValueId = getValueId(I.first);
4164     assert(ValueId);
4165     SummaryToValueIdMap[S] = *ValueId;
4166 
4167     // If this is invoked for an aliasee, we want to record the above
4168     // mapping, but then not emit a summary entry (if the aliasee is
4169     // to be imported, we will invoke this separately with IsAliasee=false).
4170     if (IsAliasee)
4171       return;
4172 
4173     if (auto *AS = dyn_cast<AliasSummary>(S)) {
4174       // Will process aliases as a post-pass because the reader wants all
4175       // global to be loaded first.
4176       Aliases.push_back(AS);
4177       return;
4178     }
4179 
4180     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
4181       NameVals.push_back(*ValueId);
4182       NameVals.push_back(Index.getModuleId(VS->modulePath()));
4183       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4184       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4185       for (auto &RI : VS->refs()) {
4186         auto RefValueId = getValueId(RI.getGUID());
4187         if (!RefValueId)
4188           continue;
4189         NameVals.push_back(*RefValueId);
4190       }
4191 
4192       // Emit the finished record.
4193       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
4194                         FSModRefsAbbrev);
4195       NameVals.clear();
4196       MaybeEmitOriginalName(*S);
4197       return;
4198     }
4199 
4200     auto GetValueId = [&](const ValueInfo &VI) -> Optional<unsigned> {
4201       GlobalValue::GUID GUID = VI.getGUID();
4202       Optional<unsigned> CallValueId = getValueId(GUID);
4203       if (CallValueId)
4204         return CallValueId;
4205       // For SamplePGO, the indirect call targets for local functions will
4206       // have its original name annotated in profile. We try to find the
4207       // corresponding PGOFuncName as the GUID.
4208       GUID = Index.getGUIDFromOriginalID(GUID);
4209       if (!GUID)
4210         return None;
4211       CallValueId = getValueId(GUID);
4212       if (!CallValueId)
4213         return None;
4214       // The mapping from OriginalId to GUID may return a GUID
4215       // that corresponds to a static variable. Filter it out here.
4216       // This can happen when
4217       // 1) There is a call to a library function which does not have
4218       // a CallValidId;
4219       // 2) There is a static variable with the  OriginalGUID identical
4220       // to the GUID of the library function in 1);
4221       // When this happens, the logic for SamplePGO kicks in and
4222       // the static variable in 2) will be found, which needs to be
4223       // filtered out.
4224       auto *GVSum = Index.getGlobalValueSummary(GUID, false);
4225       if (GVSum && GVSum->getSummaryKind() == GlobalValueSummary::GlobalVarKind)
4226         return None;
4227       return CallValueId;
4228     };
4229 
4230     auto *FS = cast<FunctionSummary>(S);
4231     writeFunctionTypeMetadataRecords(Stream, FS, GetValueId);
4232     getReferencedTypeIds(FS, ReferencedTypeIds);
4233 
4234     NameVals.push_back(*ValueId);
4235     NameVals.push_back(Index.getModuleId(FS->modulePath()));
4236     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4237     NameVals.push_back(FS->instCount());
4238     NameVals.push_back(getEncodedFFlags(FS->fflags()));
4239     NameVals.push_back(FS->entryCount());
4240 
4241     // Fill in below
4242     NameVals.push_back(0); // numrefs
4243     NameVals.push_back(0); // rorefcnt
4244     NameVals.push_back(0); // worefcnt
4245 
4246     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
4247     for (auto &RI : FS->refs()) {
4248       auto RefValueId = getValueId(RI.getGUID());
4249       if (!RefValueId)
4250         continue;
4251       NameVals.push_back(*RefValueId);
4252       if (RI.isReadOnly())
4253         RORefCnt++;
4254       else if (RI.isWriteOnly())
4255         WORefCnt++;
4256       Count++;
4257     }
4258     NameVals[6] = Count;
4259     NameVals[7] = RORefCnt;
4260     NameVals[8] = WORefCnt;
4261 
4262     bool HasProfileData = false;
4263     for (auto &EI : FS->calls()) {
4264       HasProfileData |=
4265           EI.second.getHotness() != CalleeInfo::HotnessType::Unknown;
4266       if (HasProfileData)
4267         break;
4268     }
4269 
4270     for (auto &EI : FS->calls()) {
4271       // If this GUID doesn't have a value id, it doesn't have a function
4272       // summary and we don't need to record any calls to it.
4273       Optional<unsigned> CallValueId = GetValueId(EI.first);
4274       if (!CallValueId)
4275         continue;
4276       NameVals.push_back(*CallValueId);
4277       if (HasProfileData)
4278         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
4279     }
4280 
4281     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
4282     unsigned Code =
4283         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
4284 
4285     // Emit the finished record.
4286     Stream.EmitRecord(Code, NameVals, FSAbbrev);
4287     NameVals.clear();
4288     MaybeEmitOriginalName(*S);
4289   });
4290 
4291   for (auto *AS : Aliases) {
4292     auto AliasValueId = SummaryToValueIdMap[AS];
4293     assert(AliasValueId);
4294     NameVals.push_back(AliasValueId);
4295     NameVals.push_back(Index.getModuleId(AS->modulePath()));
4296     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4297     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4298     assert(AliaseeValueId);
4299     NameVals.push_back(AliaseeValueId);
4300 
4301     // Emit the finished record.
4302     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4303     NameVals.clear();
4304     MaybeEmitOriginalName(*AS);
4305 
4306     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4307       getReferencedTypeIds(FS, ReferencedTypeIds);
4308   }
4309 
4310   if (!Index.cfiFunctionDefs().empty()) {
4311     for (auto &S : Index.cfiFunctionDefs()) {
4312       if (DefOrUseGUIDs.count(
4313               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4314         NameVals.push_back(StrtabBuilder.add(S));
4315         NameVals.push_back(S.size());
4316       }
4317     }
4318     if (!NameVals.empty()) {
4319       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4320       NameVals.clear();
4321     }
4322   }
4323 
4324   if (!Index.cfiFunctionDecls().empty()) {
4325     for (auto &S : Index.cfiFunctionDecls()) {
4326       if (DefOrUseGUIDs.count(
4327               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4328         NameVals.push_back(StrtabBuilder.add(S));
4329         NameVals.push_back(S.size());
4330       }
4331     }
4332     if (!NameVals.empty()) {
4333       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4334       NameVals.clear();
4335     }
4336   }
4337 
4338   // Walk the GUIDs that were referenced, and write the
4339   // corresponding type id records.
4340   for (auto &T : ReferencedTypeIds) {
4341     auto TidIter = Index.typeIds().equal_range(T);
4342     for (auto It = TidIter.first; It != TidIter.second; ++It) {
4343       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, It->second.first,
4344                                It->second.second);
4345       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4346       NameVals.clear();
4347     }
4348   }
4349 
4350   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4351                     ArrayRef<uint64_t>{Index.getBlockCount()});
4352 
4353   Stream.ExitBlock();
4354 }
4355 
4356 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4357 /// current llvm version, and a record for the epoch number.
4358 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4359   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4360 
4361   // Write the "user readable" string identifying the bitcode producer
4362   auto Abbv = std::make_shared<BitCodeAbbrev>();
4363   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4364   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4365   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4366   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4367   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4368                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4369 
4370   // Write the epoch version
4371   Abbv = std::make_shared<BitCodeAbbrev>();
4372   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4373   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4374   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4375   constexpr std::array<unsigned, 1> Vals = {{bitc::BITCODE_CURRENT_EPOCH}};
4376   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4377   Stream.ExitBlock();
4378 }
4379 
4380 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
4381   // Emit the module's hash.
4382   // MODULE_CODE_HASH: [5*i32]
4383   if (GenerateHash) {
4384     uint32_t Vals[5];
4385     Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
4386                                     Buffer.size() - BlockStartPos));
4387     StringRef Hash = Hasher.result();
4388     for (int Pos = 0; Pos < 20; Pos += 4) {
4389       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4390     }
4391 
4392     // Emit the finished record.
4393     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4394 
4395     if (ModHash)
4396       // Save the written hash value.
4397       llvm::copy(Vals, std::begin(*ModHash));
4398   }
4399 }
4400 
4401 void ModuleBitcodeWriter::write() {
4402   writeIdentificationBlock(Stream);
4403 
4404   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4405   size_t BlockStartPos = Buffer.size();
4406 
4407   writeModuleVersion();
4408 
4409   // Emit blockinfo, which defines the standard abbreviations etc.
4410   writeBlockInfo();
4411 
4412   // Emit information describing all of the types in the module.
4413   writeTypeTable();
4414 
4415   // Emit information about attribute groups.
4416   writeAttributeGroupTable();
4417 
4418   // Emit information about parameter attributes.
4419   writeAttributeTable();
4420 
4421   writeComdats();
4422 
4423   // Emit top-level description of module, including target triple, inline asm,
4424   // descriptors for global variables, and function prototype info.
4425   writeModuleInfo();
4426 
4427   // Emit constants.
4428   writeModuleConstants();
4429 
4430   // Emit metadata kind names.
4431   writeModuleMetadataKinds();
4432 
4433   // Emit metadata.
4434   writeModuleMetadata();
4435 
4436   // Emit module-level use-lists.
4437   if (VE.shouldPreserveUseListOrder())
4438     writeUseListBlock(nullptr);
4439 
4440   writeOperandBundleTags();
4441   writeSyncScopeNames();
4442 
4443   // Emit function bodies.
4444   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4445   for (Module::const_iterator F = M.begin(), E = M.end(); F != E; ++F)
4446     if (!F->isDeclaration())
4447       writeFunction(*F, FunctionToBitcodeIndex);
4448 
4449   // Need to write after the above call to WriteFunction which populates
4450   // the summary information in the index.
4451   if (Index)
4452     writePerModuleGlobalValueSummary();
4453 
4454   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4455 
4456   writeModuleHash(BlockStartPos);
4457 
4458   Stream.ExitBlock();
4459 }
4460 
4461 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4462                                uint32_t &Position) {
4463   support::endian::write32le(&Buffer[Position], Value);
4464   Position += 4;
4465 }
4466 
4467 /// If generating a bc file on darwin, we have to emit a
4468 /// header and trailer to make it compatible with the system archiver.  To do
4469 /// this we emit the following header, and then emit a trailer that pads the
4470 /// file out to be a multiple of 16 bytes.
4471 ///
4472 /// struct bc_header {
4473 ///   uint32_t Magic;         // 0x0B17C0DE
4474 ///   uint32_t Version;       // Version, currently always 0.
4475 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4476 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4477 ///   uint32_t CPUType;       // CPU specifier.
4478 ///   ... potentially more later ...
4479 /// };
4480 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4481                                          const Triple &TT) {
4482   unsigned CPUType = ~0U;
4483 
4484   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4485   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4486   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4487   // specific constants here because they are implicitly part of the Darwin ABI.
4488   enum {
4489     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4490     DARWIN_CPU_TYPE_X86        = 7,
4491     DARWIN_CPU_TYPE_ARM        = 12,
4492     DARWIN_CPU_TYPE_POWERPC    = 18
4493   };
4494 
4495   Triple::ArchType Arch = TT.getArch();
4496   if (Arch == Triple::x86_64)
4497     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4498   else if (Arch == Triple::x86)
4499     CPUType = DARWIN_CPU_TYPE_X86;
4500   else if (Arch == Triple::ppc)
4501     CPUType = DARWIN_CPU_TYPE_POWERPC;
4502   else if (Arch == Triple::ppc64)
4503     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
4504   else if (Arch == Triple::arm || Arch == Triple::thumb)
4505     CPUType = DARWIN_CPU_TYPE_ARM;
4506 
4507   // Traditional Bitcode starts after header.
4508   assert(Buffer.size() >= BWH_HeaderSize &&
4509          "Expected header size to be reserved");
4510   unsigned BCOffset = BWH_HeaderSize;
4511   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
4512 
4513   // Write the magic and version.
4514   unsigned Position = 0;
4515   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
4516   writeInt32ToBuffer(0, Buffer, Position); // Version.
4517   writeInt32ToBuffer(BCOffset, Buffer, Position);
4518   writeInt32ToBuffer(BCSize, Buffer, Position);
4519   writeInt32ToBuffer(CPUType, Buffer, Position);
4520 
4521   // If the file is not a multiple of 16 bytes, insert dummy padding.
4522   while (Buffer.size() & 15)
4523     Buffer.push_back(0);
4524 }
4525 
4526 /// Helper to write the header common to all bitcode files.
4527 static void writeBitcodeHeader(BitstreamWriter &Stream) {
4528   // Emit the file header.
4529   Stream.Emit((unsigned)'B', 8);
4530   Stream.Emit((unsigned)'C', 8);
4531   Stream.Emit(0x0, 4);
4532   Stream.Emit(0xC, 4);
4533   Stream.Emit(0xE, 4);
4534   Stream.Emit(0xD, 4);
4535 }
4536 
4537 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer, raw_fd_stream *FS)
4538     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer, FS, FlushThreshold)) {
4539   writeBitcodeHeader(*Stream);
4540 }
4541 
4542 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
4543 
4544 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
4545   Stream->EnterSubblock(Block, 3);
4546 
4547   auto Abbv = std::make_shared<BitCodeAbbrev>();
4548   Abbv->Add(BitCodeAbbrevOp(Record));
4549   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
4550   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
4551 
4552   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
4553 
4554   Stream->ExitBlock();
4555 }
4556 
4557 void BitcodeWriter::writeSymtab() {
4558   assert(!WroteStrtab && !WroteSymtab);
4559 
4560   // If any module has module-level inline asm, we will require a registered asm
4561   // parser for the target so that we can create an accurate symbol table for
4562   // the module.
4563   for (Module *M : Mods) {
4564     if (M->getModuleInlineAsm().empty())
4565       continue;
4566 
4567     std::string Err;
4568     const Triple TT(M->getTargetTriple());
4569     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
4570     if (!T || !T->hasMCAsmParser())
4571       return;
4572   }
4573 
4574   WroteSymtab = true;
4575   SmallVector<char, 0> Symtab;
4576   // The irsymtab::build function may be unable to create a symbol table if the
4577   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
4578   // table is not required for correctness, but we still want to be able to
4579   // write malformed modules to bitcode files, so swallow the error.
4580   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
4581     consumeError(std::move(E));
4582     return;
4583   }
4584 
4585   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
4586             {Symtab.data(), Symtab.size()});
4587 }
4588 
4589 void BitcodeWriter::writeStrtab() {
4590   assert(!WroteStrtab);
4591 
4592   std::vector<char> Strtab;
4593   StrtabBuilder.finalizeInOrder();
4594   Strtab.resize(StrtabBuilder.getSize());
4595   StrtabBuilder.write((uint8_t *)Strtab.data());
4596 
4597   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
4598             {Strtab.data(), Strtab.size()});
4599 
4600   WroteStrtab = true;
4601 }
4602 
4603 void BitcodeWriter::copyStrtab(StringRef Strtab) {
4604   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
4605   WroteStrtab = true;
4606 }
4607 
4608 void BitcodeWriter::writeModule(const Module &M,
4609                                 bool ShouldPreserveUseListOrder,
4610                                 const ModuleSummaryIndex *Index,
4611                                 bool GenerateHash, ModuleHash *ModHash) {
4612   assert(!WroteStrtab);
4613 
4614   // The Mods vector is used by irsymtab::build, which requires non-const
4615   // Modules in case it needs to materialize metadata. But the bitcode writer
4616   // requires that the module is materialized, so we can cast to non-const here,
4617   // after checking that it is in fact materialized.
4618   assert(M.isMaterialized());
4619   Mods.push_back(const_cast<Module *>(&M));
4620 
4621   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
4622                                    ShouldPreserveUseListOrder, Index,
4623                                    GenerateHash, ModHash);
4624   ModuleWriter.write();
4625 }
4626 
4627 void BitcodeWriter::writeIndex(
4628     const ModuleSummaryIndex *Index,
4629     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4630   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
4631                                  ModuleToSummariesForIndex);
4632   IndexWriter.write();
4633 }
4634 
4635 /// Write the specified module to the specified output stream.
4636 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
4637                               bool ShouldPreserveUseListOrder,
4638                               const ModuleSummaryIndex *Index,
4639                               bool GenerateHash, ModuleHash *ModHash) {
4640   SmallVector<char, 0> Buffer;
4641   Buffer.reserve(256*1024);
4642 
4643   // If this is darwin or another generic macho target, reserve space for the
4644   // header.
4645   Triple TT(M.getTargetTriple());
4646   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4647     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
4648 
4649   BitcodeWriter Writer(Buffer, dyn_cast<raw_fd_stream>(&Out));
4650   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
4651                      ModHash);
4652   Writer.writeSymtab();
4653   Writer.writeStrtab();
4654 
4655   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4656     emitDarwinBCHeaderAndTrailer(Buffer, TT);
4657 
4658   // Write the generated bitstream to "Out".
4659   if (!Buffer.empty())
4660     Out.write((char *)&Buffer.front(), Buffer.size());
4661 }
4662 
4663 void IndexBitcodeWriter::write() {
4664   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4665 
4666   writeModuleVersion();
4667 
4668   // Write the module paths in the combined index.
4669   writeModStrings();
4670 
4671   // Write the summary combined index records.
4672   writeCombinedGlobalValueSummary();
4673 
4674   Stream.ExitBlock();
4675 }
4676 
4677 // Write the specified module summary index to the given raw output stream,
4678 // where it will be written in a new bitcode block. This is used when
4679 // writing the combined index file for ThinLTO. When writing a subset of the
4680 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
4681 void llvm::WriteIndexToFile(
4682     const ModuleSummaryIndex &Index, raw_ostream &Out,
4683     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4684   SmallVector<char, 0> Buffer;
4685   Buffer.reserve(256 * 1024);
4686 
4687   BitcodeWriter Writer(Buffer);
4688   Writer.writeIndex(&Index, ModuleToSummariesForIndex);
4689   Writer.writeStrtab();
4690 
4691   Out.write((char *)&Buffer.front(), Buffer.size());
4692 }
4693 
4694 namespace {
4695 
4696 /// Class to manage the bitcode writing for a thin link bitcode file.
4697 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
4698   /// ModHash is for use in ThinLTO incremental build, generated while writing
4699   /// the module bitcode file.
4700   const ModuleHash *ModHash;
4701 
4702 public:
4703   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
4704                         BitstreamWriter &Stream,
4705                         const ModuleSummaryIndex &Index,
4706                         const ModuleHash &ModHash)
4707       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
4708                                 /*ShouldPreserveUseListOrder=*/false, &Index),
4709         ModHash(&ModHash) {}
4710 
4711   void write();
4712 
4713 private:
4714   void writeSimplifiedModuleInfo();
4715 };
4716 
4717 } // end anonymous namespace
4718 
4719 // This function writes a simpilified module info for thin link bitcode file.
4720 // It only contains the source file name along with the name(the offset and
4721 // size in strtab) and linkage for global values. For the global value info
4722 // entry, in order to keep linkage at offset 5, there are three zeros used
4723 // as padding.
4724 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
4725   SmallVector<unsigned, 64> Vals;
4726   // Emit the module's source file name.
4727   {
4728     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
4729     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
4730     if (Bits == SE_Char6)
4731       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
4732     else if (Bits == SE_Fixed7)
4733       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
4734 
4735     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
4736     auto Abbv = std::make_shared<BitCodeAbbrev>();
4737     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
4738     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4739     Abbv->Add(AbbrevOpToUse);
4740     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4741 
4742     for (const auto P : M.getSourceFileName())
4743       Vals.push_back((unsigned char)P);
4744 
4745     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
4746     Vals.clear();
4747   }
4748 
4749   // Emit the global variable information.
4750   for (const GlobalVariable &GV : M.globals()) {
4751     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
4752     Vals.push_back(StrtabBuilder.add(GV.getName()));
4753     Vals.push_back(GV.getName().size());
4754     Vals.push_back(0);
4755     Vals.push_back(0);
4756     Vals.push_back(0);
4757     Vals.push_back(getEncodedLinkage(GV));
4758 
4759     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
4760     Vals.clear();
4761   }
4762 
4763   // Emit the function proto information.
4764   for (const Function &F : M) {
4765     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
4766     Vals.push_back(StrtabBuilder.add(F.getName()));
4767     Vals.push_back(F.getName().size());
4768     Vals.push_back(0);
4769     Vals.push_back(0);
4770     Vals.push_back(0);
4771     Vals.push_back(getEncodedLinkage(F));
4772 
4773     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
4774     Vals.clear();
4775   }
4776 
4777   // Emit the alias information.
4778   for (const GlobalAlias &A : M.aliases()) {
4779     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
4780     Vals.push_back(StrtabBuilder.add(A.getName()));
4781     Vals.push_back(A.getName().size());
4782     Vals.push_back(0);
4783     Vals.push_back(0);
4784     Vals.push_back(0);
4785     Vals.push_back(getEncodedLinkage(A));
4786 
4787     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
4788     Vals.clear();
4789   }
4790 
4791   // Emit the ifunc information.
4792   for (const GlobalIFunc &I : M.ifuncs()) {
4793     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
4794     Vals.push_back(StrtabBuilder.add(I.getName()));
4795     Vals.push_back(I.getName().size());
4796     Vals.push_back(0);
4797     Vals.push_back(0);
4798     Vals.push_back(0);
4799     Vals.push_back(getEncodedLinkage(I));
4800 
4801     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
4802     Vals.clear();
4803   }
4804 }
4805 
4806 void ThinLinkBitcodeWriter::write() {
4807   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4808 
4809   writeModuleVersion();
4810 
4811   writeSimplifiedModuleInfo();
4812 
4813   writePerModuleGlobalValueSummary();
4814 
4815   // Write module hash.
4816   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
4817 
4818   Stream.ExitBlock();
4819 }
4820 
4821 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
4822                                          const ModuleSummaryIndex &Index,
4823                                          const ModuleHash &ModHash) {
4824   assert(!WroteStrtab);
4825 
4826   // The Mods vector is used by irsymtab::build, which requires non-const
4827   // Modules in case it needs to materialize metadata. But the bitcode writer
4828   // requires that the module is materialized, so we can cast to non-const here,
4829   // after checking that it is in fact materialized.
4830   assert(M.isMaterialized());
4831   Mods.push_back(const_cast<Module *>(&M));
4832 
4833   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
4834                                        ModHash);
4835   ThinLinkWriter.write();
4836 }
4837 
4838 // Write the specified thin link bitcode file to the given raw output stream,
4839 // where it will be written in a new bitcode block. This is used when
4840 // writing the per-module index file for ThinLTO.
4841 void llvm::WriteThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
4842                                       const ModuleSummaryIndex &Index,
4843                                       const ModuleHash &ModHash) {
4844   SmallVector<char, 0> Buffer;
4845   Buffer.reserve(256 * 1024);
4846 
4847   BitcodeWriter Writer(Buffer);
4848   Writer.writeThinLinkBitcode(M, Index, ModHash);
4849   Writer.writeSymtab();
4850   Writer.writeStrtab();
4851 
4852   Out.write((char *)&Buffer.front(), Buffer.size());
4853 }
4854 
4855 static const char *getSectionNameForBitcode(const Triple &T) {
4856   switch (T.getObjectFormat()) {
4857   case Triple::MachO:
4858     return "__LLVM,__bitcode";
4859   case Triple::COFF:
4860   case Triple::ELF:
4861   case Triple::Wasm:
4862   case Triple::UnknownObjectFormat:
4863     return ".llvmbc";
4864   case Triple::GOFF:
4865     llvm_unreachable("GOFF is not yet implemented");
4866     break;
4867   case Triple::XCOFF:
4868     llvm_unreachable("XCOFF is not yet implemented");
4869     break;
4870   }
4871   llvm_unreachable("Unimplemented ObjectFormatType");
4872 }
4873 
4874 static const char *getSectionNameForCommandline(const Triple &T) {
4875   switch (T.getObjectFormat()) {
4876   case Triple::MachO:
4877     return "__LLVM,__cmdline";
4878   case Triple::COFF:
4879   case Triple::ELF:
4880   case Triple::Wasm:
4881   case Triple::UnknownObjectFormat:
4882     return ".llvmcmd";
4883   case Triple::GOFF:
4884     llvm_unreachable("GOFF is not yet implemented");
4885     break;
4886   case Triple::XCOFF:
4887     llvm_unreachable("XCOFF is not yet implemented");
4888     break;
4889   }
4890   llvm_unreachable("Unimplemented ObjectFormatType");
4891 }
4892 
4893 void llvm::EmbedBitcodeInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
4894                                 bool EmbedBitcode, bool EmbedCmdline,
4895                                 const std::vector<uint8_t> &CmdArgs) {
4896   // Save llvm.compiler.used and remove it.
4897   SmallVector<Constant *, 2> UsedArray;
4898   SmallVector<GlobalValue *, 4> UsedGlobals;
4899   Type *UsedElementType = Type::getInt8Ty(M.getContext())->getPointerTo(0);
4900   GlobalVariable *Used = collectUsedGlobalVariables(M, UsedGlobals, true);
4901   for (auto *GV : UsedGlobals) {
4902     if (GV->getName() != "llvm.embedded.module" &&
4903         GV->getName() != "llvm.cmdline")
4904       UsedArray.push_back(
4905           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4906   }
4907   if (Used)
4908     Used->eraseFromParent();
4909 
4910   // Embed the bitcode for the llvm module.
4911   std::string Data;
4912   ArrayRef<uint8_t> ModuleData;
4913   Triple T(M.getTargetTriple());
4914 
4915   if (EmbedBitcode) {
4916     if (Buf.getBufferSize() == 0 ||
4917         !isBitcode((const unsigned char *)Buf.getBufferStart(),
4918                    (const unsigned char *)Buf.getBufferEnd())) {
4919       // If the input is LLVM Assembly, bitcode is produced by serializing
4920       // the module. Use-lists order need to be preserved in this case.
4921       llvm::raw_string_ostream OS(Data);
4922       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
4923       ModuleData =
4924           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
4925     } else
4926       // If the input is LLVM bitcode, write the input byte stream directly.
4927       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
4928                                      Buf.getBufferSize());
4929   }
4930   llvm::Constant *ModuleConstant =
4931       llvm::ConstantDataArray::get(M.getContext(), ModuleData);
4932   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
4933       M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
4934       ModuleConstant);
4935   GV->setSection(getSectionNameForBitcode(T));
4936   // Set alignment to 1 to prevent padding between two contributions from input
4937   // sections after linking.
4938   GV->setAlignment(Align(1));
4939   UsedArray.push_back(
4940       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4941   if (llvm::GlobalVariable *Old =
4942           M.getGlobalVariable("llvm.embedded.module", true)) {
4943     assert(Old->hasOneUse() &&
4944            "llvm.embedded.module can only be used once in llvm.compiler.used");
4945     GV->takeName(Old);
4946     Old->eraseFromParent();
4947   } else {
4948     GV->setName("llvm.embedded.module");
4949   }
4950 
4951   // Skip if only bitcode needs to be embedded.
4952   if (EmbedCmdline) {
4953     // Embed command-line options.
4954     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CmdArgs.data()),
4955                               CmdArgs.size());
4956     llvm::Constant *CmdConstant =
4957         llvm::ConstantDataArray::get(M.getContext(), CmdData);
4958     GV = new llvm::GlobalVariable(M, CmdConstant->getType(), true,
4959                                   llvm::GlobalValue::PrivateLinkage,
4960                                   CmdConstant);
4961     GV->setSection(getSectionNameForCommandline(T));
4962     GV->setAlignment(Align(1));
4963     UsedArray.push_back(
4964         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4965     if (llvm::GlobalVariable *Old = M.getGlobalVariable("llvm.cmdline", true)) {
4966       assert(Old->hasOneUse() &&
4967              "llvm.cmdline can only be used once in llvm.compiler.used");
4968       GV->takeName(Old);
4969       Old->eraseFromParent();
4970     } else {
4971       GV->setName("llvm.cmdline");
4972     }
4973   }
4974 
4975   if (UsedArray.empty())
4976     return;
4977 
4978   // Recreate llvm.compiler.used.
4979   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
4980   auto *NewUsed = new GlobalVariable(
4981       M, ATy, false, llvm::GlobalValue::AppendingLinkage,
4982       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
4983   NewUsed->setSection("llvm.metadata");
4984 }
4985