xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision 9254ebe3c0c446c049c12db492698cfcde02922a)
1 //===--- Bitcode/Writer/BitcodeWriter.cpp - Bitcode Writer ----------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // Bitcode writer implementation.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "ValueEnumerator.h"
15 #include "llvm/ADT/StringExtras.h"
16 #include "llvm/ADT/Triple.h"
17 #include "llvm/Bitcode/BitstreamWriter.h"
18 #include "llvm/Bitcode/LLVMBitCodes.h"
19 #include "llvm/Bitcode/ReaderWriter.h"
20 #include "llvm/IR/CallSite.h"
21 #include "llvm/IR/Constants.h"
22 #include "llvm/IR/DebugInfoMetadata.h"
23 #include "llvm/IR/DerivedTypes.h"
24 #include "llvm/IR/InlineAsm.h"
25 #include "llvm/IR/Instructions.h"
26 #include "llvm/IR/LLVMContext.h"
27 #include "llvm/IR/Module.h"
28 #include "llvm/IR/Operator.h"
29 #include "llvm/IR/UseListOrder.h"
30 #include "llvm/IR/ValueSymbolTable.h"
31 #include "llvm/Support/ErrorHandling.h"
32 #include "llvm/Support/MathExtras.h"
33 #include "llvm/Support/Program.h"
34 #include "llvm/Support/SHA1.h"
35 #include "llvm/Support/raw_ostream.h"
36 #include <cctype>
37 #include <map>
38 using namespace llvm;
39 
40 /// These are manifest constants used by the bitcode writer. They do not need to
41 /// be kept in sync with the reader, but need to be consistent within this file.
42 enum {
43   // VALUE_SYMTAB_BLOCK abbrev id's.
44   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
45   VST_ENTRY_7_ABBREV,
46   VST_ENTRY_6_ABBREV,
47   VST_BBENTRY_6_ABBREV,
48 
49   // CONSTANTS_BLOCK abbrev id's.
50   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
51   CONSTANTS_INTEGER_ABBREV,
52   CONSTANTS_CE_CAST_Abbrev,
53   CONSTANTS_NULL_Abbrev,
54 
55   // FUNCTION_BLOCK abbrev id's.
56   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
57   FUNCTION_INST_BINOP_ABBREV,
58   FUNCTION_INST_BINOP_FLAGS_ABBREV,
59   FUNCTION_INST_CAST_ABBREV,
60   FUNCTION_INST_RET_VOID_ABBREV,
61   FUNCTION_INST_RET_VAL_ABBREV,
62   FUNCTION_INST_UNREACHABLE_ABBREV,
63   FUNCTION_INST_GEP_ABBREV,
64 };
65 
66 /// Abstract class to manage the bitcode writing, subclassed for each bitcode
67 /// file type. Owns the BitstreamWriter, and includes the main entry point for
68 /// writing.
69 class BitcodeWriter {
70 protected:
71   /// Pointer to the buffer allocated by caller for bitcode writing.
72   const SmallVectorImpl<char> &Buffer;
73 
74   /// The stream created and owned by the BitodeWriter.
75   BitstreamWriter Stream;
76 
77   /// Saves the offset of the VSTOffset record that must eventually be
78   /// backpatched with the offset of the actual VST.
79   uint64_t VSTOffsetPlaceholder = 0;
80 
81 public:
82   /// Constructs a BitcodeWriter object, and initializes a BitstreamRecord,
83   /// writing to the provided \p Buffer.
84   BitcodeWriter(SmallVectorImpl<char> &Buffer)
85       : Buffer(Buffer), Stream(Buffer) {}
86 
87   virtual ~BitcodeWriter() = default;
88 
89   /// Main entry point to write the bitcode file, which writes the bitcode
90   /// header and will then invoke the virtual writeBlocks() method.
91   void write();
92 
93 private:
94   /// Derived classes must implement this to write the corresponding blocks for
95   /// that bitcode file type.
96   virtual void writeBlocks() = 0;
97 
98 protected:
99   bool hasVSTOffsetPlaceholder() { return VSTOffsetPlaceholder != 0; }
100   void writeValueSymbolTableForwardDecl();
101   void writeBitcodeHeader();
102 };
103 
104 /// Class to manage the bitcode writing for a module.
105 class ModuleBitcodeWriter : public BitcodeWriter {
106   /// The Module to write to bitcode.
107   const Module &M;
108 
109   /// Enumerates ids for all values in the module.
110   ValueEnumerator VE;
111 
112   /// Optional per-module index to write for ThinLTO.
113   const ModuleSummaryIndex *Index;
114 
115   /// True if a module hash record should be written.
116   bool GenerateHash;
117 
118   /// The start bit of the module block, for use in generating a module hash
119   uint64_t BitcodeStartBit = 0;
120 
121 public:
122   /// Constructs a ModuleBitcodeWriter object for the given Module,
123   /// writing to the provided \p Buffer.
124   ModuleBitcodeWriter(const Module *M, SmallVectorImpl<char> &Buffer,
125                       bool ShouldPreserveUseListOrder,
126                       const ModuleSummaryIndex *Index, bool GenerateHash)
127       : BitcodeWriter(Buffer), M(*M), VE(*M, ShouldPreserveUseListOrder),
128         Index(Index), GenerateHash(GenerateHash) {
129     // Save the start bit of the actual bitcode, in case there is space
130     // saved at the start for the darwin header above. The reader stream
131     // will start at the bitcode, and we need the offset of the VST
132     // to line up.
133     BitcodeStartBit = Stream.GetCurrentBitNo();
134   }
135 
136 private:
137   /// Main entry point for writing a module to bitcode, invoked by
138   /// BitcodeWriter::write() after it writes the header.
139   void writeBlocks() override;
140 
141   /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
142   /// current llvm version, and a record for the epoch number.
143   void writeIdentificationBlock();
144 
145   /// Emit the current module to the bitstream.
146   void writeModule();
147 
148   uint64_t bitcodeStartBit() { return BitcodeStartBit; }
149 
150   void writeStringRecord(unsigned Code, StringRef Str, unsigned AbbrevToUse);
151   void writeAttributeGroupTable();
152   void writeAttributeTable();
153   void writeTypeTable();
154   void writeComdats();
155   void writeModuleInfo();
156   void writeValueAsMetadata(const ValueAsMetadata *MD,
157                             SmallVectorImpl<uint64_t> &Record);
158   void writeMDTuple(const MDTuple *N, SmallVectorImpl<uint64_t> &Record,
159                     unsigned Abbrev);
160   unsigned createDILocationAbbrev();
161   void writeDILocation(const DILocation *N, SmallVectorImpl<uint64_t> &Record,
162                        unsigned &Abbrev);
163   unsigned createGenericDINodeAbbrev();
164   void writeGenericDINode(const GenericDINode *N,
165                           SmallVectorImpl<uint64_t> &Record, unsigned &Abbrev);
166   void writeDISubrange(const DISubrange *N, SmallVectorImpl<uint64_t> &Record,
167                        unsigned Abbrev);
168   void writeDIEnumerator(const DIEnumerator *N,
169                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
170   void writeDIBasicType(const DIBasicType *N, SmallVectorImpl<uint64_t> &Record,
171                         unsigned Abbrev);
172   void writeDIDerivedType(const DIDerivedType *N,
173                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
174   void writeDICompositeType(const DICompositeType *N,
175                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
176   void writeDISubroutineType(const DISubroutineType *N,
177                              SmallVectorImpl<uint64_t> &Record,
178                              unsigned Abbrev);
179   void writeDIFile(const DIFile *N, SmallVectorImpl<uint64_t> &Record,
180                    unsigned Abbrev);
181   void writeDICompileUnit(const DICompileUnit *N,
182                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
183   void writeDISubprogram(const DISubprogram *N,
184                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
185   void writeDILexicalBlock(const DILexicalBlock *N,
186                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
187   void writeDILexicalBlockFile(const DILexicalBlockFile *N,
188                                SmallVectorImpl<uint64_t> &Record,
189                                unsigned Abbrev);
190   void writeDINamespace(const DINamespace *N, SmallVectorImpl<uint64_t> &Record,
191                         unsigned Abbrev);
192   void writeDIMacro(const DIMacro *N, SmallVectorImpl<uint64_t> &Record,
193                     unsigned Abbrev);
194   void writeDIMacroFile(const DIMacroFile *N, SmallVectorImpl<uint64_t> &Record,
195                         unsigned Abbrev);
196   void writeDIModule(const DIModule *N, SmallVectorImpl<uint64_t> &Record,
197                      unsigned Abbrev);
198   void writeDITemplateTypeParameter(const DITemplateTypeParameter *N,
199                                     SmallVectorImpl<uint64_t> &Record,
200                                     unsigned Abbrev);
201   void writeDITemplateValueParameter(const DITemplateValueParameter *N,
202                                      SmallVectorImpl<uint64_t> &Record,
203                                      unsigned Abbrev);
204   void writeDIGlobalVariable(const DIGlobalVariable *N,
205                              SmallVectorImpl<uint64_t> &Record,
206                              unsigned Abbrev);
207   void writeDILocalVariable(const DILocalVariable *N,
208                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
209   void writeDIExpression(const DIExpression *N,
210                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
211   void writeDIObjCProperty(const DIObjCProperty *N,
212                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
213   void writeDIImportedEntity(const DIImportedEntity *N,
214                              SmallVectorImpl<uint64_t> &Record,
215                              unsigned Abbrev);
216   unsigned createNamedMetadataAbbrev();
217   void writeNamedMetadata(SmallVectorImpl<uint64_t> &Record);
218   unsigned createMetadataStringsAbbrev();
219   void writeMetadataStrings(ArrayRef<const Metadata *> Strings,
220                             SmallVectorImpl<uint64_t> &Record);
221   void writeMetadataRecords(ArrayRef<const Metadata *> MDs,
222                             SmallVectorImpl<uint64_t> &Record);
223   void writeModuleMetadata();
224   void writeFunctionMetadata(const Function &F);
225   void writeMetadataAttachment(const Function &F);
226   void writeModuleMetadataStore();
227   void writeOperandBundleTags();
228   void writeConstants(unsigned FirstVal, unsigned LastVal, bool isGlobal);
229   void writeModuleConstants();
230   bool pushValueAndType(const Value *V, unsigned InstID,
231                         SmallVectorImpl<unsigned> &Vals);
232   void writeOperandBundles(ImmutableCallSite CS, unsigned InstID);
233   void pushValue(const Value *V, unsigned InstID,
234                  SmallVectorImpl<unsigned> &Vals);
235   void pushValueSigned(const Value *V, unsigned InstID,
236                        SmallVectorImpl<uint64_t> &Vals);
237   void writeInstruction(const Instruction &I, unsigned InstID,
238                         SmallVectorImpl<unsigned> &Vals);
239   void writeValueSymbolTable(
240       const ValueSymbolTable &VST, bool IsModuleLevel = false,
241       DenseMap<const Function *, uint64_t> *FunctionToBitcodeIndex = nullptr);
242   void writeUseList(UseListOrder &&Order);
243   void writeUseListBlock(const Function *F);
244   void
245   writeFunction(const Function &F,
246                 DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
247   void writeBlockInfo();
248   void writePerModuleFunctionSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
249                                            GlobalValueSummary *Summary,
250                                            unsigned ValueID,
251                                            unsigned FSCallsAbbrev,
252                                            unsigned FSCallsProfileAbbrev,
253                                            const Function &F);
254   void writeModuleLevelReferences(const GlobalVariable &V,
255                                   SmallVector<uint64_t, 64> &NameVals,
256                                   unsigned FSModRefsAbbrev);
257   void writePerModuleGlobalValueSummary();
258   void writeModuleHash(size_t BlockStartPos);
259 };
260 
261 /// Class to manage the bitcode writing for a combined index.
262 class IndexBitcodeWriter : public BitcodeWriter {
263   /// The combined index to write to bitcode.
264   const ModuleSummaryIndex &Index;
265 
266   /// When writing a subset of the index for distributed backends, client
267   /// provides a map of modules to the corresponding GUIDs/summaries to write.
268   std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex;
269 
270   /// Map that holds the correspondence between the GUID used in the combined
271   /// index and a value id generated by this class to use in references.
272   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
273 
274   /// Tracks the last value id recorded in the GUIDToValueMap.
275   unsigned GlobalValueId = 0;
276 
277 public:
278   /// Constructs a IndexBitcodeWriter object for the given combined index,
279   /// writing to the provided \p Buffer. When writing a subset of the index
280   /// for a distributed backend, provide a \p ModuleToSummariesForIndex map.
281   IndexBitcodeWriter(SmallVectorImpl<char> &Buffer,
282                      const ModuleSummaryIndex &Index,
283                      std::map<std::string, GVSummaryMapTy>
284                          *ModuleToSummariesForIndex = nullptr)
285       : BitcodeWriter(Buffer), Index(Index),
286         ModuleToSummariesForIndex(ModuleToSummariesForIndex) {
287     // Assign unique value ids to all summaries to be written, for use
288     // in writing out the call graph edges. Save the mapping from GUID
289     // to the new global value id to use when writing those edges, which
290     // are currently saved in the index in terms of GUID.
291     for (const auto &I : *this)
292       GUIDToValueIdMap[I.first] = ++GlobalValueId;
293   }
294 
295   /// The below iterator returns the GUID and associated summary.
296   typedef std::pair<GlobalValue::GUID, GlobalValueSummary *> GVInfo;
297 
298   /// Iterator over the value GUID and summaries to be written to bitcode,
299   /// hides the details of whether they are being pulled from the entire
300   /// index or just those in a provided ModuleToSummariesForIndex map.
301   class iterator
302       : public llvm::iterator_facade_base<iterator, std::forward_iterator_tag,
303                                           GVInfo> {
304     /// Enables access to parent class.
305     const IndexBitcodeWriter &Writer;
306 
307     // Iterators used when writing only those summaries in a provided
308     // ModuleToSummariesForIndex map:
309 
310     /// Points to the last element in outer ModuleToSummariesForIndex map.
311     std::map<std::string, GVSummaryMapTy>::iterator ModuleSummariesBack;
312     /// Iterator on outer ModuleToSummariesForIndex map.
313     std::map<std::string, GVSummaryMapTy>::iterator ModuleSummariesIter;
314     /// Iterator on an inner global variable summary map.
315     GVSummaryMapTy::iterator ModuleGVSummariesIter;
316 
317     // Iterators used when writing all summaries in the index:
318 
319     /// Points to the last element in the Index outer GlobalValueMap.
320     const_gvsummary_iterator IndexSummariesBack;
321     /// Iterator on outer GlobalValueMap.
322     const_gvsummary_iterator IndexSummariesIter;
323     /// Iterator on an inner GlobalValueSummaryList.
324     GlobalValueSummaryList::const_iterator IndexGVSummariesIter;
325 
326   public:
327     /// Construct iterator from parent \p Writer and indicate if we are
328     /// constructing the end iterator.
329     iterator(const IndexBitcodeWriter &Writer, bool IsAtEnd) : Writer(Writer) {
330       // Set up the appropriate set of iterators given whether we are writing
331       // the full index or just a subset.
332       // Can't setup the Back or inner iterators if the corresponding map
333       // is empty. This will be handled specially in operator== as well.
334       if (Writer.ModuleToSummariesForIndex &&
335           !Writer.ModuleToSummariesForIndex->empty()) {
336         ModuleSummariesBack =
337             std::prev(Writer.ModuleToSummariesForIndex->end());
338         ModuleSummariesIter = Writer.ModuleToSummariesForIndex->begin();
339         ModuleGVSummariesIter = !IsAtEnd ? ModuleSummariesIter->second.begin()
340                                          : ModuleSummariesBack->second.end();
341       } else if (!Writer.ModuleToSummariesForIndex &&
342                  Writer.Index.begin() != Writer.Index.end()) {
343         IndexSummariesBack = std::prev(Writer.Index.end());
344         IndexSummariesIter = Writer.Index.begin();
345         IndexGVSummariesIter = !IsAtEnd ? IndexSummariesIter->second.begin()
346                                         : IndexSummariesBack->second.end();
347       }
348     }
349 
350     /// Increment the appropriate set of iterators.
351     iterator &operator++() {
352       // First the inner iterator is incremented, then if it is at the end
353       // and there are more outer iterations to go, the inner is reset to
354       // the start of the next inner list.
355       if (Writer.ModuleToSummariesForIndex) {
356         ++ModuleGVSummariesIter;
357         if (ModuleGVSummariesIter == ModuleSummariesIter->second.end() &&
358             ModuleSummariesIter != ModuleSummariesBack) {
359           ++ModuleSummariesIter;
360           ModuleGVSummariesIter = ModuleSummariesIter->second.begin();
361         }
362       } else {
363         ++IndexGVSummariesIter;
364         if (IndexGVSummariesIter == IndexSummariesIter->second.end() &&
365             IndexSummariesIter != IndexSummariesBack) {
366           ++IndexSummariesIter;
367           IndexGVSummariesIter = IndexSummariesIter->second.begin();
368         }
369       }
370       return *this;
371     }
372 
373     /// Access the <GUID,GlobalValueSummary*> pair corresponding to the current
374     /// outer and inner iterator positions.
375     GVInfo operator*() {
376       if (Writer.ModuleToSummariesForIndex)
377         return std::make_pair(ModuleGVSummariesIter->first,
378                               ModuleGVSummariesIter->second);
379       return std::make_pair(IndexSummariesIter->first,
380                             IndexGVSummariesIter->get());
381     }
382 
383     /// Checks if the iterators are equal, with special handling for empty
384     /// indexes.
385     bool operator==(const iterator &RHS) const {
386       if (Writer.ModuleToSummariesForIndex) {
387         // First ensure that both are writing the same subset.
388         if (Writer.ModuleToSummariesForIndex !=
389             RHS.Writer.ModuleToSummariesForIndex)
390           return false;
391         // Already determined above that maps are the same, so if one is
392         // empty, they both are.
393         if (Writer.ModuleToSummariesForIndex->empty())
394           return true;
395         return ModuleGVSummariesIter == RHS.ModuleGVSummariesIter;
396       }
397       // First ensure RHS also writing the full index, and that both are
398       // writing the same full index.
399       if (RHS.Writer.ModuleToSummariesForIndex ||
400           &Writer.Index != &RHS.Writer.Index)
401         return false;
402       // Already determined above that maps are the same, so if one is
403       // empty, they both are.
404       if (Writer.Index.begin() == Writer.Index.end())
405         return true;
406       return IndexGVSummariesIter == RHS.IndexGVSummariesIter;
407     }
408   };
409 
410   /// Obtain the start iterator over the summaries to be written.
411   iterator begin() { return iterator(*this, /*IsAtEnd=*/false); }
412   /// Obtain the end iterator over the summaries to be written.
413   iterator end() { return iterator(*this, /*IsAtEnd=*/true); }
414 
415 private:
416   /// Main entry point for writing a combined index to bitcode, invoked by
417   /// BitcodeWriter::write() after it writes the header.
418   void writeBlocks() override;
419 
420   void writeIndex();
421   void writeModStrings();
422   void writeCombinedValueSymbolTable();
423   void writeCombinedGlobalValueSummary();
424 
425   /// Indicates whether the provided \p ModulePath should be written into
426   /// the module string table, e.g. if full index written or if it is in
427   /// the provided subset.
428   bool doIncludeModule(StringRef ModulePath) {
429     return !ModuleToSummariesForIndex ||
430            ModuleToSummariesForIndex->count(ModulePath);
431   }
432 
433   bool hasValueId(GlobalValue::GUID ValGUID) {
434     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
435     return VMI != GUIDToValueIdMap.end();
436   }
437   unsigned getValueId(GlobalValue::GUID ValGUID) {
438     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
439     // If this GUID doesn't have an entry, assign one.
440     if (VMI == GUIDToValueIdMap.end()) {
441       GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
442       return GlobalValueId;
443     } else {
444       return VMI->second;
445     }
446   }
447   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
448 };
449 
450 static unsigned getEncodedCastOpcode(unsigned Opcode) {
451   switch (Opcode) {
452   default: llvm_unreachable("Unknown cast instruction!");
453   case Instruction::Trunc   : return bitc::CAST_TRUNC;
454   case Instruction::ZExt    : return bitc::CAST_ZEXT;
455   case Instruction::SExt    : return bitc::CAST_SEXT;
456   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
457   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
458   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
459   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
460   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
461   case Instruction::FPExt   : return bitc::CAST_FPEXT;
462   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
463   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
464   case Instruction::BitCast : return bitc::CAST_BITCAST;
465   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
466   }
467 }
468 
469 static unsigned getEncodedBinaryOpcode(unsigned Opcode) {
470   switch (Opcode) {
471   default: llvm_unreachable("Unknown binary instruction!");
472   case Instruction::Add:
473   case Instruction::FAdd: return bitc::BINOP_ADD;
474   case Instruction::Sub:
475   case Instruction::FSub: return bitc::BINOP_SUB;
476   case Instruction::Mul:
477   case Instruction::FMul: return bitc::BINOP_MUL;
478   case Instruction::UDiv: return bitc::BINOP_UDIV;
479   case Instruction::FDiv:
480   case Instruction::SDiv: return bitc::BINOP_SDIV;
481   case Instruction::URem: return bitc::BINOP_UREM;
482   case Instruction::FRem:
483   case Instruction::SRem: return bitc::BINOP_SREM;
484   case Instruction::Shl:  return bitc::BINOP_SHL;
485   case Instruction::LShr: return bitc::BINOP_LSHR;
486   case Instruction::AShr: return bitc::BINOP_ASHR;
487   case Instruction::And:  return bitc::BINOP_AND;
488   case Instruction::Or:   return bitc::BINOP_OR;
489   case Instruction::Xor:  return bitc::BINOP_XOR;
490   }
491 }
492 
493 static unsigned getEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
494   switch (Op) {
495   default: llvm_unreachable("Unknown RMW operation!");
496   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
497   case AtomicRMWInst::Add: return bitc::RMW_ADD;
498   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
499   case AtomicRMWInst::And: return bitc::RMW_AND;
500   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
501   case AtomicRMWInst::Or: return bitc::RMW_OR;
502   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
503   case AtomicRMWInst::Max: return bitc::RMW_MAX;
504   case AtomicRMWInst::Min: return bitc::RMW_MIN;
505   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
506   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
507   }
508 }
509 
510 static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
511   switch (Ordering) {
512   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
513   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
514   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
515   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
516   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
517   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
518   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
519   }
520   llvm_unreachable("Invalid ordering");
521 }
522 
523 static unsigned getEncodedSynchScope(SynchronizationScope SynchScope) {
524   switch (SynchScope) {
525   case SingleThread: return bitc::SYNCHSCOPE_SINGLETHREAD;
526   case CrossThread: return bitc::SYNCHSCOPE_CROSSTHREAD;
527   }
528   llvm_unreachable("Invalid synch scope");
529 }
530 
531 void ModuleBitcodeWriter::writeStringRecord(unsigned Code, StringRef Str,
532                                             unsigned AbbrevToUse) {
533   SmallVector<unsigned, 64> Vals;
534 
535   // Code: [strchar x N]
536   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
537     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
538       AbbrevToUse = 0;
539     Vals.push_back(Str[i]);
540   }
541 
542   // Emit the finished record.
543   Stream.EmitRecord(Code, Vals, AbbrevToUse);
544 }
545 
546 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
547   switch (Kind) {
548   case Attribute::Alignment:
549     return bitc::ATTR_KIND_ALIGNMENT;
550   case Attribute::AllocSize:
551     return bitc::ATTR_KIND_ALLOC_SIZE;
552   case Attribute::AlwaysInline:
553     return bitc::ATTR_KIND_ALWAYS_INLINE;
554   case Attribute::ArgMemOnly:
555     return bitc::ATTR_KIND_ARGMEMONLY;
556   case Attribute::Builtin:
557     return bitc::ATTR_KIND_BUILTIN;
558   case Attribute::ByVal:
559     return bitc::ATTR_KIND_BY_VAL;
560   case Attribute::Convergent:
561     return bitc::ATTR_KIND_CONVERGENT;
562   case Attribute::InAlloca:
563     return bitc::ATTR_KIND_IN_ALLOCA;
564   case Attribute::Cold:
565     return bitc::ATTR_KIND_COLD;
566   case Attribute::InaccessibleMemOnly:
567     return bitc::ATTR_KIND_INACCESSIBLEMEM_ONLY;
568   case Attribute::InaccessibleMemOrArgMemOnly:
569     return bitc::ATTR_KIND_INACCESSIBLEMEM_OR_ARGMEMONLY;
570   case Attribute::InlineHint:
571     return bitc::ATTR_KIND_INLINE_HINT;
572   case Attribute::InReg:
573     return bitc::ATTR_KIND_IN_REG;
574   case Attribute::JumpTable:
575     return bitc::ATTR_KIND_JUMP_TABLE;
576   case Attribute::MinSize:
577     return bitc::ATTR_KIND_MIN_SIZE;
578   case Attribute::Naked:
579     return bitc::ATTR_KIND_NAKED;
580   case Attribute::Nest:
581     return bitc::ATTR_KIND_NEST;
582   case Attribute::NoAlias:
583     return bitc::ATTR_KIND_NO_ALIAS;
584   case Attribute::NoBuiltin:
585     return bitc::ATTR_KIND_NO_BUILTIN;
586   case Attribute::NoCapture:
587     return bitc::ATTR_KIND_NO_CAPTURE;
588   case Attribute::NoDuplicate:
589     return bitc::ATTR_KIND_NO_DUPLICATE;
590   case Attribute::NoImplicitFloat:
591     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
592   case Attribute::NoInline:
593     return bitc::ATTR_KIND_NO_INLINE;
594   case Attribute::NoRecurse:
595     return bitc::ATTR_KIND_NO_RECURSE;
596   case Attribute::NonLazyBind:
597     return bitc::ATTR_KIND_NON_LAZY_BIND;
598   case Attribute::NonNull:
599     return bitc::ATTR_KIND_NON_NULL;
600   case Attribute::Dereferenceable:
601     return bitc::ATTR_KIND_DEREFERENCEABLE;
602   case Attribute::DereferenceableOrNull:
603     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
604   case Attribute::NoRedZone:
605     return bitc::ATTR_KIND_NO_RED_ZONE;
606   case Attribute::NoReturn:
607     return bitc::ATTR_KIND_NO_RETURN;
608   case Attribute::NoUnwind:
609     return bitc::ATTR_KIND_NO_UNWIND;
610   case Attribute::OptimizeForSize:
611     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
612   case Attribute::OptimizeNone:
613     return bitc::ATTR_KIND_OPTIMIZE_NONE;
614   case Attribute::ReadNone:
615     return bitc::ATTR_KIND_READ_NONE;
616   case Attribute::ReadOnly:
617     return bitc::ATTR_KIND_READ_ONLY;
618   case Attribute::Returned:
619     return bitc::ATTR_KIND_RETURNED;
620   case Attribute::ReturnsTwice:
621     return bitc::ATTR_KIND_RETURNS_TWICE;
622   case Attribute::SExt:
623     return bitc::ATTR_KIND_S_EXT;
624   case Attribute::StackAlignment:
625     return bitc::ATTR_KIND_STACK_ALIGNMENT;
626   case Attribute::StackProtect:
627     return bitc::ATTR_KIND_STACK_PROTECT;
628   case Attribute::StackProtectReq:
629     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
630   case Attribute::StackProtectStrong:
631     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
632   case Attribute::SafeStack:
633     return bitc::ATTR_KIND_SAFESTACK;
634   case Attribute::StructRet:
635     return bitc::ATTR_KIND_STRUCT_RET;
636   case Attribute::SanitizeAddress:
637     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
638   case Attribute::SanitizeThread:
639     return bitc::ATTR_KIND_SANITIZE_THREAD;
640   case Attribute::SanitizeMemory:
641     return bitc::ATTR_KIND_SANITIZE_MEMORY;
642   case Attribute::SwiftError:
643     return bitc::ATTR_KIND_SWIFT_ERROR;
644   case Attribute::SwiftSelf:
645     return bitc::ATTR_KIND_SWIFT_SELF;
646   case Attribute::UWTable:
647     return bitc::ATTR_KIND_UW_TABLE;
648   case Attribute::ZExt:
649     return bitc::ATTR_KIND_Z_EXT;
650   case Attribute::EndAttrKinds:
651     llvm_unreachable("Can not encode end-attribute kinds marker.");
652   case Attribute::None:
653     llvm_unreachable("Can not encode none-attribute.");
654   }
655 
656   llvm_unreachable("Trying to encode unknown attribute");
657 }
658 
659 void ModuleBitcodeWriter::writeAttributeGroupTable() {
660   const std::vector<AttributeSet> &AttrGrps = VE.getAttributeGroups();
661   if (AttrGrps.empty()) return;
662 
663   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
664 
665   SmallVector<uint64_t, 64> Record;
666   for (unsigned i = 0, e = AttrGrps.size(); i != e; ++i) {
667     AttributeSet AS = AttrGrps[i];
668     for (unsigned i = 0, e = AS.getNumSlots(); i != e; ++i) {
669       AttributeSet A = AS.getSlotAttributes(i);
670 
671       Record.push_back(VE.getAttributeGroupID(A));
672       Record.push_back(AS.getSlotIndex(i));
673 
674       for (AttributeSet::iterator I = AS.begin(0), E = AS.end(0);
675            I != E; ++I) {
676         Attribute Attr = *I;
677         if (Attr.isEnumAttribute()) {
678           Record.push_back(0);
679           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
680         } else if (Attr.isIntAttribute()) {
681           Record.push_back(1);
682           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
683           Record.push_back(Attr.getValueAsInt());
684         } else {
685           StringRef Kind = Attr.getKindAsString();
686           StringRef Val = Attr.getValueAsString();
687 
688           Record.push_back(Val.empty() ? 3 : 4);
689           Record.append(Kind.begin(), Kind.end());
690           Record.push_back(0);
691           if (!Val.empty()) {
692             Record.append(Val.begin(), Val.end());
693             Record.push_back(0);
694           }
695         }
696       }
697 
698       Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
699       Record.clear();
700     }
701   }
702 
703   Stream.ExitBlock();
704 }
705 
706 void ModuleBitcodeWriter::writeAttributeTable() {
707   const std::vector<AttributeSet> &Attrs = VE.getAttributes();
708   if (Attrs.empty()) return;
709 
710   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
711 
712   SmallVector<uint64_t, 64> Record;
713   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
714     const AttributeSet &A = Attrs[i];
715     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i)
716       Record.push_back(VE.getAttributeGroupID(A.getSlotAttributes(i)));
717 
718     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
719     Record.clear();
720   }
721 
722   Stream.ExitBlock();
723 }
724 
725 /// WriteTypeTable - Write out the type table for a module.
726 void ModuleBitcodeWriter::writeTypeTable() {
727   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
728 
729   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
730   SmallVector<uint64_t, 64> TypeVals;
731 
732   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
733 
734   // Abbrev for TYPE_CODE_POINTER.
735   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
736   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
737   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
738   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
739   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
740 
741   // Abbrev for TYPE_CODE_FUNCTION.
742   Abbv = new BitCodeAbbrev();
743   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
744   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
745   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
746   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
747 
748   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
749 
750   // Abbrev for TYPE_CODE_STRUCT_ANON.
751   Abbv = new BitCodeAbbrev();
752   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
753   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
754   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
755   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
756 
757   unsigned StructAnonAbbrev = Stream.EmitAbbrev(Abbv);
758 
759   // Abbrev for TYPE_CODE_STRUCT_NAME.
760   Abbv = new BitCodeAbbrev();
761   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
762   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
763   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
764   unsigned StructNameAbbrev = Stream.EmitAbbrev(Abbv);
765 
766   // Abbrev for TYPE_CODE_STRUCT_NAMED.
767   Abbv = new BitCodeAbbrev();
768   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
769   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
770   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
771   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
772 
773   unsigned StructNamedAbbrev = Stream.EmitAbbrev(Abbv);
774 
775   // Abbrev for TYPE_CODE_ARRAY.
776   Abbv = new BitCodeAbbrev();
777   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
778   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
779   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
780 
781   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
782 
783   // Emit an entry count so the reader can reserve space.
784   TypeVals.push_back(TypeList.size());
785   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
786   TypeVals.clear();
787 
788   // Loop over all of the types, emitting each in turn.
789   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
790     Type *T = TypeList[i];
791     int AbbrevToUse = 0;
792     unsigned Code = 0;
793 
794     switch (T->getTypeID()) {
795     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
796     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
797     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
798     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
799     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
800     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
801     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
802     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
803     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
804     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
805     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
806     case Type::IntegerTyID:
807       // INTEGER: [width]
808       Code = bitc::TYPE_CODE_INTEGER;
809       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
810       break;
811     case Type::PointerTyID: {
812       PointerType *PTy = cast<PointerType>(T);
813       // POINTER: [pointee type, address space]
814       Code = bitc::TYPE_CODE_POINTER;
815       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
816       unsigned AddressSpace = PTy->getAddressSpace();
817       TypeVals.push_back(AddressSpace);
818       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
819       break;
820     }
821     case Type::FunctionTyID: {
822       FunctionType *FT = cast<FunctionType>(T);
823       // FUNCTION: [isvararg, retty, paramty x N]
824       Code = bitc::TYPE_CODE_FUNCTION;
825       TypeVals.push_back(FT->isVarArg());
826       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
827       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
828         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
829       AbbrevToUse = FunctionAbbrev;
830       break;
831     }
832     case Type::StructTyID: {
833       StructType *ST = cast<StructType>(T);
834       // STRUCT: [ispacked, eltty x N]
835       TypeVals.push_back(ST->isPacked());
836       // Output all of the element types.
837       for (StructType::element_iterator I = ST->element_begin(),
838            E = ST->element_end(); I != E; ++I)
839         TypeVals.push_back(VE.getTypeID(*I));
840 
841       if (ST->isLiteral()) {
842         Code = bitc::TYPE_CODE_STRUCT_ANON;
843         AbbrevToUse = StructAnonAbbrev;
844       } else {
845         if (ST->isOpaque()) {
846           Code = bitc::TYPE_CODE_OPAQUE;
847         } else {
848           Code = bitc::TYPE_CODE_STRUCT_NAMED;
849           AbbrevToUse = StructNamedAbbrev;
850         }
851 
852         // Emit the name if it is present.
853         if (!ST->getName().empty())
854           writeStringRecord(bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
855                             StructNameAbbrev);
856       }
857       break;
858     }
859     case Type::ArrayTyID: {
860       ArrayType *AT = cast<ArrayType>(T);
861       // ARRAY: [numelts, eltty]
862       Code = bitc::TYPE_CODE_ARRAY;
863       TypeVals.push_back(AT->getNumElements());
864       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
865       AbbrevToUse = ArrayAbbrev;
866       break;
867     }
868     case Type::VectorTyID: {
869       VectorType *VT = cast<VectorType>(T);
870       // VECTOR [numelts, eltty]
871       Code = bitc::TYPE_CODE_VECTOR;
872       TypeVals.push_back(VT->getNumElements());
873       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
874       break;
875     }
876     }
877 
878     // Emit the finished record.
879     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
880     TypeVals.clear();
881   }
882 
883   Stream.ExitBlock();
884 }
885 
886 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
887   switch (Linkage) {
888   case GlobalValue::ExternalLinkage:
889     return 0;
890   case GlobalValue::WeakAnyLinkage:
891     return 16;
892   case GlobalValue::AppendingLinkage:
893     return 2;
894   case GlobalValue::InternalLinkage:
895     return 3;
896   case GlobalValue::LinkOnceAnyLinkage:
897     return 18;
898   case GlobalValue::ExternalWeakLinkage:
899     return 7;
900   case GlobalValue::CommonLinkage:
901     return 8;
902   case GlobalValue::PrivateLinkage:
903     return 9;
904   case GlobalValue::WeakODRLinkage:
905     return 17;
906   case GlobalValue::LinkOnceODRLinkage:
907     return 19;
908   case GlobalValue::AvailableExternallyLinkage:
909     return 12;
910   }
911   llvm_unreachable("Invalid linkage");
912 }
913 
914 static unsigned getEncodedLinkage(const GlobalValue &GV) {
915   return getEncodedLinkage(GV.getLinkage());
916 }
917 
918 // Decode the flags for GlobalValue in the summary
919 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
920   uint64_t RawFlags = 0;
921 
922   RawFlags |= Flags.HasSection; // bool
923 
924   // Linkage don't need to be remapped at that time for the summary. Any future
925   // change to the getEncodedLinkage() function will need to be taken into
926   // account here as well.
927   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
928 
929   return RawFlags;
930 }
931 
932 static unsigned getEncodedVisibility(const GlobalValue &GV) {
933   switch (GV.getVisibility()) {
934   case GlobalValue::DefaultVisibility:   return 0;
935   case GlobalValue::HiddenVisibility:    return 1;
936   case GlobalValue::ProtectedVisibility: return 2;
937   }
938   llvm_unreachable("Invalid visibility");
939 }
940 
941 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
942   switch (GV.getDLLStorageClass()) {
943   case GlobalValue::DefaultStorageClass:   return 0;
944   case GlobalValue::DLLImportStorageClass: return 1;
945   case GlobalValue::DLLExportStorageClass: return 2;
946   }
947   llvm_unreachable("Invalid DLL storage class");
948 }
949 
950 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
951   switch (GV.getThreadLocalMode()) {
952     case GlobalVariable::NotThreadLocal:         return 0;
953     case GlobalVariable::GeneralDynamicTLSModel: return 1;
954     case GlobalVariable::LocalDynamicTLSModel:   return 2;
955     case GlobalVariable::InitialExecTLSModel:    return 3;
956     case GlobalVariable::LocalExecTLSModel:      return 4;
957   }
958   llvm_unreachable("Invalid TLS model");
959 }
960 
961 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
962   switch (C.getSelectionKind()) {
963   case Comdat::Any:
964     return bitc::COMDAT_SELECTION_KIND_ANY;
965   case Comdat::ExactMatch:
966     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
967   case Comdat::Largest:
968     return bitc::COMDAT_SELECTION_KIND_LARGEST;
969   case Comdat::NoDuplicates:
970     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
971   case Comdat::SameSize:
972     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
973   }
974   llvm_unreachable("Invalid selection kind");
975 }
976 
977 void ModuleBitcodeWriter::writeComdats() {
978   SmallVector<unsigned, 64> Vals;
979   for (const Comdat *C : VE.getComdats()) {
980     // COMDAT: [selection_kind, name]
981     Vals.push_back(getEncodedComdatSelectionKind(*C));
982     size_t Size = C->getName().size();
983     assert(isUInt<32>(Size));
984     Vals.push_back(Size);
985     for (char Chr : C->getName())
986       Vals.push_back((unsigned char)Chr);
987     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
988     Vals.clear();
989   }
990 }
991 
992 /// Write a record that will eventually hold the word offset of the
993 /// module-level VST. For now the offset is 0, which will be backpatched
994 /// after the real VST is written. Saves the bit offset to backpatch.
995 void BitcodeWriter::writeValueSymbolTableForwardDecl() {
996   // Write a placeholder value in for the offset of the real VST,
997   // which is written after the function blocks so that it can include
998   // the offset of each function. The placeholder offset will be
999   // updated when the real VST is written.
1000   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1001   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1002   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1003   // hold the real VST offset. Must use fixed instead of VBR as we don't
1004   // know how many VBR chunks to reserve ahead of time.
1005   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1006   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(Abbv);
1007 
1008   // Emit the placeholder
1009   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1010   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1011 
1012   // Compute and save the bit offset to the placeholder, which will be
1013   // patched when the real VST is written. We can simply subtract the 32-bit
1014   // fixed size from the current bit number to get the location to backpatch.
1015   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1016 }
1017 
1018 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1019 
1020 /// Determine the encoding to use for the given string name and length.
1021 static StringEncoding getStringEncoding(const char *Str, unsigned StrLen) {
1022   bool isChar6 = true;
1023   for (const char *C = Str, *E = C + StrLen; C != E; ++C) {
1024     if (isChar6)
1025       isChar6 = BitCodeAbbrevOp::isChar6(*C);
1026     if ((unsigned char)*C & 128)
1027       // don't bother scanning the rest.
1028       return SE_Fixed8;
1029   }
1030   if (isChar6)
1031     return SE_Char6;
1032   else
1033     return SE_Fixed7;
1034 }
1035 
1036 /// Emit top-level description of module, including target triple, inline asm,
1037 /// descriptors for global variables, and function prototype info.
1038 /// Returns the bit offset to backpatch with the location of the real VST.
1039 void ModuleBitcodeWriter::writeModuleInfo() {
1040   // Emit various pieces of data attached to a module.
1041   if (!M.getTargetTriple().empty())
1042     writeStringRecord(bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1043                       0 /*TODO*/);
1044   const std::string &DL = M.getDataLayoutStr();
1045   if (!DL.empty())
1046     writeStringRecord(bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1047   if (!M.getModuleInlineAsm().empty())
1048     writeStringRecord(bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1049                       0 /*TODO*/);
1050 
1051   // Emit information about sections and GC, computing how many there are. Also
1052   // compute the maximum alignment value.
1053   std::map<std::string, unsigned> SectionMap;
1054   std::map<std::string, unsigned> GCMap;
1055   unsigned MaxAlignment = 0;
1056   unsigned MaxGlobalType = 0;
1057   for (const GlobalValue &GV : M.globals()) {
1058     MaxAlignment = std::max(MaxAlignment, GV.getAlignment());
1059     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1060     if (GV.hasSection()) {
1061       // Give section names unique ID's.
1062       unsigned &Entry = SectionMap[GV.getSection()];
1063       if (!Entry) {
1064         writeStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1065                           0 /*TODO*/);
1066         Entry = SectionMap.size();
1067       }
1068     }
1069   }
1070   for (const Function &F : M) {
1071     MaxAlignment = std::max(MaxAlignment, F.getAlignment());
1072     if (F.hasSection()) {
1073       // Give section names unique ID's.
1074       unsigned &Entry = SectionMap[F.getSection()];
1075       if (!Entry) {
1076         writeStringRecord(bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1077                           0 /*TODO*/);
1078         Entry = SectionMap.size();
1079       }
1080     }
1081     if (F.hasGC()) {
1082       // Same for GC names.
1083       unsigned &Entry = GCMap[F.getGC()];
1084       if (!Entry) {
1085         writeStringRecord(bitc::MODULE_CODE_GCNAME, F.getGC(), 0 /*TODO*/);
1086         Entry = GCMap.size();
1087       }
1088     }
1089   }
1090 
1091   // Emit abbrev for globals, now that we know # sections and max alignment.
1092   unsigned SimpleGVarAbbrev = 0;
1093   if (!M.global_empty()) {
1094     // Add an abbrev for common globals with no visibility or thread localness.
1095     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1096     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1097     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1098                               Log2_32_Ceil(MaxGlobalType+1)));
1099     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1100                                                            //| explicitType << 1
1101                                                            //| constant
1102     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1103     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1104     if (MaxAlignment == 0)                                 // Alignment.
1105       Abbv->Add(BitCodeAbbrevOp(0));
1106     else {
1107       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
1108       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1109                                Log2_32_Ceil(MaxEncAlignment+1)));
1110     }
1111     if (SectionMap.empty())                                    // Section.
1112       Abbv->Add(BitCodeAbbrevOp(0));
1113     else
1114       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1115                                Log2_32_Ceil(SectionMap.size()+1)));
1116     // Don't bother emitting vis + thread local.
1117     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
1118   }
1119 
1120   // Emit the global variable information.
1121   SmallVector<unsigned, 64> Vals;
1122   for (const GlobalVariable &GV : M.globals()) {
1123     unsigned AbbrevToUse = 0;
1124 
1125     // GLOBALVAR: [type, isconst, initid,
1126     //             linkage, alignment, section, visibility, threadlocal,
1127     //             unnamed_addr, externally_initialized, dllstorageclass,
1128     //             comdat]
1129     Vals.push_back(VE.getTypeID(GV.getValueType()));
1130     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1131     Vals.push_back(GV.isDeclaration() ? 0 :
1132                    (VE.getValueID(GV.getInitializer()) + 1));
1133     Vals.push_back(getEncodedLinkage(GV));
1134     Vals.push_back(Log2_32(GV.getAlignment())+1);
1135     Vals.push_back(GV.hasSection() ? SectionMap[GV.getSection()] : 0);
1136     if (GV.isThreadLocal() ||
1137         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1138         GV.hasUnnamedAddr() || GV.isExternallyInitialized() ||
1139         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1140         GV.hasComdat()) {
1141       Vals.push_back(getEncodedVisibility(GV));
1142       Vals.push_back(getEncodedThreadLocalMode(GV));
1143       Vals.push_back(GV.hasUnnamedAddr());
1144       Vals.push_back(GV.isExternallyInitialized());
1145       Vals.push_back(getEncodedDLLStorageClass(GV));
1146       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1147     } else {
1148       AbbrevToUse = SimpleGVarAbbrev;
1149     }
1150 
1151     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1152     Vals.clear();
1153   }
1154 
1155   // Emit the function proto information.
1156   for (const Function &F : M) {
1157     // FUNCTION:  [type, callingconv, isproto, linkage, paramattrs, alignment,
1158     //             section, visibility, gc, unnamed_addr, prologuedata,
1159     //             dllstorageclass, comdat, prefixdata, personalityfn]
1160     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1161     Vals.push_back(F.getCallingConv());
1162     Vals.push_back(F.isDeclaration());
1163     Vals.push_back(getEncodedLinkage(F));
1164     Vals.push_back(VE.getAttributeID(F.getAttributes()));
1165     Vals.push_back(Log2_32(F.getAlignment())+1);
1166     Vals.push_back(F.hasSection() ? SectionMap[F.getSection()] : 0);
1167     Vals.push_back(getEncodedVisibility(F));
1168     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1169     Vals.push_back(F.hasUnnamedAddr());
1170     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1171                                        : 0);
1172     Vals.push_back(getEncodedDLLStorageClass(F));
1173     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1174     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1175                                      : 0);
1176     Vals.push_back(
1177         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1178 
1179     unsigned AbbrevToUse = 0;
1180     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1181     Vals.clear();
1182   }
1183 
1184   // Emit the alias information.
1185   for (const GlobalAlias &A : M.aliases()) {
1186     // ALIAS: [alias type, aliasee val#, linkage, visibility]
1187     Vals.push_back(VE.getTypeID(A.getValueType()));
1188     Vals.push_back(A.getType()->getAddressSpace());
1189     Vals.push_back(VE.getValueID(A.getAliasee()));
1190     Vals.push_back(getEncodedLinkage(A));
1191     Vals.push_back(getEncodedVisibility(A));
1192     Vals.push_back(getEncodedDLLStorageClass(A));
1193     Vals.push_back(getEncodedThreadLocalMode(A));
1194     Vals.push_back(A.hasUnnamedAddr());
1195     unsigned AbbrevToUse = 0;
1196     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1197     Vals.clear();
1198   }
1199 
1200   // Emit the ifunc information.
1201   for (const GlobalIFunc &I : M.ifuncs()) {
1202     // IFUNC: [ifunc type, address space, resolver val#, linkage, visibility]
1203     Vals.push_back(VE.getTypeID(I.getValueType()));
1204     Vals.push_back(I.getType()->getAddressSpace());
1205     Vals.push_back(VE.getValueID(I.getResolver()));
1206     Vals.push_back(getEncodedLinkage(I));
1207     Vals.push_back(getEncodedVisibility(I));
1208     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1209     Vals.clear();
1210   }
1211 
1212   // Emit the module's source file name.
1213   {
1214     StringEncoding Bits = getStringEncoding(M.getSourceFileName().data(),
1215                                             M.getSourceFileName().size());
1216     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1217     if (Bits == SE_Char6)
1218       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1219     else if (Bits == SE_Fixed7)
1220       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1221 
1222     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1223     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1224     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1225     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1226     Abbv->Add(AbbrevOpToUse);
1227     unsigned FilenameAbbrev = Stream.EmitAbbrev(Abbv);
1228 
1229     for (const auto P : M.getSourceFileName())
1230       Vals.push_back((unsigned char)P);
1231 
1232     // Emit the finished record.
1233     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1234     Vals.clear();
1235   }
1236 
1237   // If we have a VST, write the VSTOFFSET record placeholder.
1238   if (M.getValueSymbolTable().empty())
1239     return;
1240   writeValueSymbolTableForwardDecl();
1241 }
1242 
1243 static uint64_t getOptimizationFlags(const Value *V) {
1244   uint64_t Flags = 0;
1245 
1246   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1247     if (OBO->hasNoSignedWrap())
1248       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1249     if (OBO->hasNoUnsignedWrap())
1250       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1251   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1252     if (PEO->isExact())
1253       Flags |= 1 << bitc::PEO_EXACT;
1254   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1255     if (FPMO->hasUnsafeAlgebra())
1256       Flags |= FastMathFlags::UnsafeAlgebra;
1257     if (FPMO->hasNoNaNs())
1258       Flags |= FastMathFlags::NoNaNs;
1259     if (FPMO->hasNoInfs())
1260       Flags |= FastMathFlags::NoInfs;
1261     if (FPMO->hasNoSignedZeros())
1262       Flags |= FastMathFlags::NoSignedZeros;
1263     if (FPMO->hasAllowReciprocal())
1264       Flags |= FastMathFlags::AllowReciprocal;
1265   }
1266 
1267   return Flags;
1268 }
1269 
1270 void ModuleBitcodeWriter::writeValueAsMetadata(
1271     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1272   // Mimic an MDNode with a value as one operand.
1273   Value *V = MD->getValue();
1274   Record.push_back(VE.getTypeID(V->getType()));
1275   Record.push_back(VE.getValueID(V));
1276   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1277   Record.clear();
1278 }
1279 
1280 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1281                                        SmallVectorImpl<uint64_t> &Record,
1282                                        unsigned Abbrev) {
1283   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1284     Metadata *MD = N->getOperand(i);
1285     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1286            "Unexpected function-local metadata");
1287     Record.push_back(VE.getMetadataOrNullID(MD));
1288   }
1289   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1290                                     : bitc::METADATA_NODE,
1291                     Record, Abbrev);
1292   Record.clear();
1293 }
1294 
1295 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1296   // Assume the column is usually under 128, and always output the inlined-at
1297   // location (it's never more expensive than building an array size 1).
1298   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1299   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1300   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1301   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1302   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1303   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1304   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1305   return Stream.EmitAbbrev(Abbv);
1306 }
1307 
1308 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1309                                           SmallVectorImpl<uint64_t> &Record,
1310                                           unsigned &Abbrev) {
1311   if (!Abbrev)
1312     Abbrev = createDILocationAbbrev();
1313 
1314   Record.push_back(N->isDistinct());
1315   Record.push_back(N->getLine());
1316   Record.push_back(N->getColumn());
1317   Record.push_back(VE.getMetadataID(N->getScope()));
1318   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1319 
1320   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1321   Record.clear();
1322 }
1323 
1324 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1325   // Assume the column is usually under 128, and always output the inlined-at
1326   // location (it's never more expensive than building an array size 1).
1327   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1328   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1329   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1330   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1331   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1332   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1333   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1334   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1335   return Stream.EmitAbbrev(Abbv);
1336 }
1337 
1338 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1339                                              SmallVectorImpl<uint64_t> &Record,
1340                                              unsigned &Abbrev) {
1341   if (!Abbrev)
1342     Abbrev = createGenericDINodeAbbrev();
1343 
1344   Record.push_back(N->isDistinct());
1345   Record.push_back(N->getTag());
1346   Record.push_back(0); // Per-tag version field; unused for now.
1347 
1348   for (auto &I : N->operands())
1349     Record.push_back(VE.getMetadataOrNullID(I));
1350 
1351   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1352   Record.clear();
1353 }
1354 
1355 static uint64_t rotateSign(int64_t I) {
1356   uint64_t U = I;
1357   return I < 0 ? ~(U << 1) : U << 1;
1358 }
1359 
1360 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1361                                           SmallVectorImpl<uint64_t> &Record,
1362                                           unsigned Abbrev) {
1363   Record.push_back(N->isDistinct());
1364   Record.push_back(N->getCount());
1365   Record.push_back(rotateSign(N->getLowerBound()));
1366 
1367   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1368   Record.clear();
1369 }
1370 
1371 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1372                                             SmallVectorImpl<uint64_t> &Record,
1373                                             unsigned Abbrev) {
1374   Record.push_back(N->isDistinct());
1375   Record.push_back(rotateSign(N->getValue()));
1376   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1377 
1378   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1379   Record.clear();
1380 }
1381 
1382 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1383                                            SmallVectorImpl<uint64_t> &Record,
1384                                            unsigned Abbrev) {
1385   Record.push_back(N->isDistinct());
1386   Record.push_back(N->getTag());
1387   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1388   Record.push_back(N->getSizeInBits());
1389   Record.push_back(N->getAlignInBits());
1390   Record.push_back(N->getEncoding());
1391 
1392   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1393   Record.clear();
1394 }
1395 
1396 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1397                                              SmallVectorImpl<uint64_t> &Record,
1398                                              unsigned Abbrev) {
1399   Record.push_back(N->isDistinct());
1400   Record.push_back(N->getTag());
1401   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1402   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1403   Record.push_back(N->getLine());
1404   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1405   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1406   Record.push_back(N->getSizeInBits());
1407   Record.push_back(N->getAlignInBits());
1408   Record.push_back(N->getOffsetInBits());
1409   Record.push_back(N->getFlags());
1410   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1411 
1412   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1413   Record.clear();
1414 }
1415 
1416 void ModuleBitcodeWriter::writeDICompositeType(
1417     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1418     unsigned Abbrev) {
1419   const unsigned IsNotUsedInOldTypeRef = 0x2;
1420   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1421   Record.push_back(N->getTag());
1422   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1423   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1424   Record.push_back(N->getLine());
1425   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1426   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1427   Record.push_back(N->getSizeInBits());
1428   Record.push_back(N->getAlignInBits());
1429   Record.push_back(N->getOffsetInBits());
1430   Record.push_back(N->getFlags());
1431   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1432   Record.push_back(N->getRuntimeLang());
1433   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1434   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1435   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1436 
1437   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1438   Record.clear();
1439 }
1440 
1441 void ModuleBitcodeWriter::writeDISubroutineType(
1442     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1443     unsigned Abbrev) {
1444   const unsigned HasNoOldTypeRefs = 0x2;
1445   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1446   Record.push_back(N->getFlags());
1447   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1448 
1449   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1450   Record.clear();
1451 }
1452 
1453 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1454                                       SmallVectorImpl<uint64_t> &Record,
1455                                       unsigned Abbrev) {
1456   Record.push_back(N->isDistinct());
1457   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1458   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1459 
1460   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1461   Record.clear();
1462 }
1463 
1464 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1465                                              SmallVectorImpl<uint64_t> &Record,
1466                                              unsigned Abbrev) {
1467   assert(N->isDistinct() && "Expected distinct compile units");
1468   Record.push_back(/* IsDistinct */ true);
1469   Record.push_back(N->getSourceLanguage());
1470   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1471   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1472   Record.push_back(N->isOptimized());
1473   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1474   Record.push_back(N->getRuntimeVersion());
1475   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1476   Record.push_back(N->getEmissionKind());
1477   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1478   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1479   Record.push_back(/* subprograms */ 0);
1480   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1481   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1482   Record.push_back(N->getDWOId());
1483   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1484 
1485   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1486   Record.clear();
1487 }
1488 
1489 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1490                                             SmallVectorImpl<uint64_t> &Record,
1491                                             unsigned Abbrev) {
1492   Record.push_back(N->isDistinct());
1493   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1494   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1495   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1496   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1497   Record.push_back(N->getLine());
1498   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1499   Record.push_back(N->isLocalToUnit());
1500   Record.push_back(N->isDefinition());
1501   Record.push_back(N->getScopeLine());
1502   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1503   Record.push_back(N->getVirtuality());
1504   Record.push_back(N->getVirtualIndex());
1505   Record.push_back(N->getFlags());
1506   Record.push_back(N->isOptimized());
1507   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1508   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1509   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1510   Record.push_back(VE.getMetadataOrNullID(N->getVariables().get()));
1511 
1512   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1513   Record.clear();
1514 }
1515 
1516 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1517                                               SmallVectorImpl<uint64_t> &Record,
1518                                               unsigned Abbrev) {
1519   Record.push_back(N->isDistinct());
1520   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1521   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1522   Record.push_back(N->getLine());
1523   Record.push_back(N->getColumn());
1524 
1525   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1526   Record.clear();
1527 }
1528 
1529 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1530     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1531     unsigned Abbrev) {
1532   Record.push_back(N->isDistinct());
1533   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1534   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1535   Record.push_back(N->getDiscriminator());
1536 
1537   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1538   Record.clear();
1539 }
1540 
1541 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1542                                            SmallVectorImpl<uint64_t> &Record,
1543                                            unsigned Abbrev) {
1544   Record.push_back(N->isDistinct());
1545   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1546   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1547   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1548   Record.push_back(N->getLine());
1549 
1550   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1551   Record.clear();
1552 }
1553 
1554 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1555                                        SmallVectorImpl<uint64_t> &Record,
1556                                        unsigned Abbrev) {
1557   Record.push_back(N->isDistinct());
1558   Record.push_back(N->getMacinfoType());
1559   Record.push_back(N->getLine());
1560   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1561   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1562 
1563   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1564   Record.clear();
1565 }
1566 
1567 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1568                                            SmallVectorImpl<uint64_t> &Record,
1569                                            unsigned Abbrev) {
1570   Record.push_back(N->isDistinct());
1571   Record.push_back(N->getMacinfoType());
1572   Record.push_back(N->getLine());
1573   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1574   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1575 
1576   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1577   Record.clear();
1578 }
1579 
1580 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1581                                         SmallVectorImpl<uint64_t> &Record,
1582                                         unsigned Abbrev) {
1583   Record.push_back(N->isDistinct());
1584   for (auto &I : N->operands())
1585     Record.push_back(VE.getMetadataOrNullID(I));
1586 
1587   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1588   Record.clear();
1589 }
1590 
1591 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1592     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1593     unsigned Abbrev) {
1594   Record.push_back(N->isDistinct());
1595   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1596   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1597 
1598   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1599   Record.clear();
1600 }
1601 
1602 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1603     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1604     unsigned Abbrev) {
1605   Record.push_back(N->isDistinct());
1606   Record.push_back(N->getTag());
1607   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1608   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1609   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1610 
1611   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1612   Record.clear();
1613 }
1614 
1615 void ModuleBitcodeWriter::writeDIGlobalVariable(
1616     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1617     unsigned Abbrev) {
1618   Record.push_back(N->isDistinct());
1619   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1620   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1621   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1622   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1623   Record.push_back(N->getLine());
1624   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1625   Record.push_back(N->isLocalToUnit());
1626   Record.push_back(N->isDefinition());
1627   Record.push_back(VE.getMetadataOrNullID(N->getRawVariable()));
1628   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1629 
1630   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1631   Record.clear();
1632 }
1633 
1634 void ModuleBitcodeWriter::writeDILocalVariable(
1635     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
1636     unsigned Abbrev) {
1637   Record.push_back(N->isDistinct());
1638   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1639   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1640   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1641   Record.push_back(N->getLine());
1642   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1643   Record.push_back(N->getArg());
1644   Record.push_back(N->getFlags());
1645 
1646   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1647   Record.clear();
1648 }
1649 
1650 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
1651                                             SmallVectorImpl<uint64_t> &Record,
1652                                             unsigned Abbrev) {
1653   Record.reserve(N->getElements().size() + 1);
1654 
1655   Record.push_back(N->isDistinct());
1656   Record.append(N->elements_begin(), N->elements_end());
1657 
1658   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
1659   Record.clear();
1660 }
1661 
1662 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
1663                                               SmallVectorImpl<uint64_t> &Record,
1664                                               unsigned Abbrev) {
1665   Record.push_back(N->isDistinct());
1666   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1667   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1668   Record.push_back(N->getLine());
1669   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
1670   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
1671   Record.push_back(N->getAttributes());
1672   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1673 
1674   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
1675   Record.clear();
1676 }
1677 
1678 void ModuleBitcodeWriter::writeDIImportedEntity(
1679     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
1680     unsigned Abbrev) {
1681   Record.push_back(N->isDistinct());
1682   Record.push_back(N->getTag());
1683   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1684   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
1685   Record.push_back(N->getLine());
1686   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1687 
1688   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
1689   Record.clear();
1690 }
1691 
1692 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
1693   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1694   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
1695   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1696   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1697   return Stream.EmitAbbrev(Abbv);
1698 }
1699 
1700 void ModuleBitcodeWriter::writeNamedMetadata(
1701     SmallVectorImpl<uint64_t> &Record) {
1702   if (M.named_metadata_empty())
1703     return;
1704 
1705   unsigned Abbrev = createNamedMetadataAbbrev();
1706   for (const NamedMDNode &NMD : M.named_metadata()) {
1707     // Write name.
1708     StringRef Str = NMD.getName();
1709     Record.append(Str.bytes_begin(), Str.bytes_end());
1710     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
1711     Record.clear();
1712 
1713     // Write named metadata operands.
1714     for (const MDNode *N : NMD.operands())
1715       Record.push_back(VE.getMetadataID(N));
1716     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
1717     Record.clear();
1718   }
1719 }
1720 
1721 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
1722   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1723   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
1724   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
1725   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
1726   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
1727   return Stream.EmitAbbrev(Abbv);
1728 }
1729 
1730 /// Write out a record for MDString.
1731 ///
1732 /// All the metadata strings in a metadata block are emitted in a single
1733 /// record.  The sizes and strings themselves are shoved into a blob.
1734 void ModuleBitcodeWriter::writeMetadataStrings(
1735     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
1736   if (Strings.empty())
1737     return;
1738 
1739   // Start the record with the number of strings.
1740   Record.push_back(bitc::METADATA_STRINGS);
1741   Record.push_back(Strings.size());
1742 
1743   // Emit the sizes of the strings in the blob.
1744   SmallString<256> Blob;
1745   {
1746     BitstreamWriter W(Blob);
1747     for (const Metadata *MD : Strings)
1748       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
1749     W.FlushToWord();
1750   }
1751 
1752   // Add the offset to the strings to the record.
1753   Record.push_back(Blob.size());
1754 
1755   // Add the strings to the blob.
1756   for (const Metadata *MD : Strings)
1757     Blob.append(cast<MDString>(MD)->getString());
1758 
1759   // Emit the final record.
1760   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
1761   Record.clear();
1762 }
1763 
1764 void ModuleBitcodeWriter::writeMetadataRecords(
1765     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record) {
1766   if (MDs.empty())
1767     return;
1768 
1769   // Initialize MDNode abbreviations.
1770 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
1771 #include "llvm/IR/Metadata.def"
1772 
1773   for (const Metadata *MD : MDs) {
1774     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
1775       assert(N->isResolved() && "Expected forward references to be resolved");
1776 
1777       switch (N->getMetadataID()) {
1778       default:
1779         llvm_unreachable("Invalid MDNode subclass");
1780 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
1781   case Metadata::CLASS##Kind:                                                  \
1782     write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                       \
1783     continue;
1784 #include "llvm/IR/Metadata.def"
1785       }
1786     }
1787     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
1788   }
1789 }
1790 
1791 void ModuleBitcodeWriter::writeModuleMetadata() {
1792   if (!VE.hasMDs() && M.named_metadata_empty())
1793     return;
1794 
1795   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1796   SmallVector<uint64_t, 64> Record;
1797   writeMetadataStrings(VE.getMDStrings(), Record);
1798   writeMetadataRecords(VE.getNonMDStrings(), Record);
1799   writeNamedMetadata(Record);
1800   Stream.ExitBlock();
1801 }
1802 
1803 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
1804   if (!VE.hasMDs())
1805     return;
1806 
1807   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1808   SmallVector<uint64_t, 64> Record;
1809   writeMetadataStrings(VE.getMDStrings(), Record);
1810   writeMetadataRecords(VE.getNonMDStrings(), Record);
1811   Stream.ExitBlock();
1812 }
1813 
1814 void ModuleBitcodeWriter::writeMetadataAttachment(const Function &F) {
1815   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
1816 
1817   SmallVector<uint64_t, 64> Record;
1818 
1819   // Write metadata attachments
1820   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
1821   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
1822   F.getAllMetadata(MDs);
1823   if (!MDs.empty()) {
1824     for (const auto &I : MDs) {
1825       Record.push_back(I.first);
1826       Record.push_back(VE.getMetadataID(I.second));
1827     }
1828     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1829     Record.clear();
1830   }
1831 
1832   for (const BasicBlock &BB : F)
1833     for (const Instruction &I : BB) {
1834       MDs.clear();
1835       I.getAllMetadataOtherThanDebugLoc(MDs);
1836 
1837       // If no metadata, ignore instruction.
1838       if (MDs.empty()) continue;
1839 
1840       Record.push_back(VE.getInstructionID(&I));
1841 
1842       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1843         Record.push_back(MDs[i].first);
1844         Record.push_back(VE.getMetadataID(MDs[i].second));
1845       }
1846       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1847       Record.clear();
1848     }
1849 
1850   Stream.ExitBlock();
1851 }
1852 
1853 void ModuleBitcodeWriter::writeModuleMetadataStore() {
1854   SmallVector<uint64_t, 64> Record;
1855 
1856   // Write metadata kinds
1857   // METADATA_KIND - [n x [id, name]]
1858   SmallVector<StringRef, 8> Names;
1859   M.getMDKindNames(Names);
1860 
1861   if (Names.empty()) return;
1862 
1863   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
1864 
1865   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
1866     Record.push_back(MDKindID);
1867     StringRef KName = Names[MDKindID];
1868     Record.append(KName.begin(), KName.end());
1869 
1870     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
1871     Record.clear();
1872   }
1873 
1874   Stream.ExitBlock();
1875 }
1876 
1877 void ModuleBitcodeWriter::writeOperandBundleTags() {
1878   // Write metadata kinds
1879   //
1880   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
1881   //
1882   // OPERAND_BUNDLE_TAG - [strchr x N]
1883 
1884   SmallVector<StringRef, 8> Tags;
1885   M.getOperandBundleTags(Tags);
1886 
1887   if (Tags.empty())
1888     return;
1889 
1890   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
1891 
1892   SmallVector<uint64_t, 64> Record;
1893 
1894   for (auto Tag : Tags) {
1895     Record.append(Tag.begin(), Tag.end());
1896 
1897     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
1898     Record.clear();
1899   }
1900 
1901   Stream.ExitBlock();
1902 }
1903 
1904 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1905   if ((int64_t)V >= 0)
1906     Vals.push_back(V << 1);
1907   else
1908     Vals.push_back((-V << 1) | 1);
1909 }
1910 
1911 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
1912                                          bool isGlobal) {
1913   if (FirstVal == LastVal) return;
1914 
1915   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
1916 
1917   unsigned AggregateAbbrev = 0;
1918   unsigned String8Abbrev = 0;
1919   unsigned CString7Abbrev = 0;
1920   unsigned CString6Abbrev = 0;
1921   // If this is a constant pool for the module, emit module-specific abbrevs.
1922   if (isGlobal) {
1923     // Abbrev for CST_CODE_AGGREGATE.
1924     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1925     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
1926     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1927     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
1928     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
1929 
1930     // Abbrev for CST_CODE_STRING.
1931     Abbv = new BitCodeAbbrev();
1932     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
1933     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1934     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1935     String8Abbrev = Stream.EmitAbbrev(Abbv);
1936     // Abbrev for CST_CODE_CSTRING.
1937     Abbv = new BitCodeAbbrev();
1938     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1939     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1940     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1941     CString7Abbrev = Stream.EmitAbbrev(Abbv);
1942     // Abbrev for CST_CODE_CSTRING.
1943     Abbv = new BitCodeAbbrev();
1944     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1945     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1946     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1947     CString6Abbrev = Stream.EmitAbbrev(Abbv);
1948   }
1949 
1950   SmallVector<uint64_t, 64> Record;
1951 
1952   const ValueEnumerator::ValueList &Vals = VE.getValues();
1953   Type *LastTy = nullptr;
1954   for (unsigned i = FirstVal; i != LastVal; ++i) {
1955     const Value *V = Vals[i].first;
1956     // If we need to switch types, do so now.
1957     if (V->getType() != LastTy) {
1958       LastTy = V->getType();
1959       Record.push_back(VE.getTypeID(LastTy));
1960       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
1961                         CONSTANTS_SETTYPE_ABBREV);
1962       Record.clear();
1963     }
1964 
1965     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
1966       Record.push_back(unsigned(IA->hasSideEffects()) |
1967                        unsigned(IA->isAlignStack()) << 1 |
1968                        unsigned(IA->getDialect()&1) << 2);
1969 
1970       // Add the asm string.
1971       const std::string &AsmStr = IA->getAsmString();
1972       Record.push_back(AsmStr.size());
1973       Record.append(AsmStr.begin(), AsmStr.end());
1974 
1975       // Add the constraint string.
1976       const std::string &ConstraintStr = IA->getConstraintString();
1977       Record.push_back(ConstraintStr.size());
1978       Record.append(ConstraintStr.begin(), ConstraintStr.end());
1979       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
1980       Record.clear();
1981       continue;
1982     }
1983     const Constant *C = cast<Constant>(V);
1984     unsigned Code = -1U;
1985     unsigned AbbrevToUse = 0;
1986     if (C->isNullValue()) {
1987       Code = bitc::CST_CODE_NULL;
1988     } else if (isa<UndefValue>(C)) {
1989       Code = bitc::CST_CODE_UNDEF;
1990     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
1991       if (IV->getBitWidth() <= 64) {
1992         uint64_t V = IV->getSExtValue();
1993         emitSignedInt64(Record, V);
1994         Code = bitc::CST_CODE_INTEGER;
1995         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
1996       } else {                             // Wide integers, > 64 bits in size.
1997         // We have an arbitrary precision integer value to write whose
1998         // bit width is > 64. However, in canonical unsigned integer
1999         // format it is likely that the high bits are going to be zero.
2000         // So, we only write the number of active words.
2001         unsigned NWords = IV->getValue().getActiveWords();
2002         const uint64_t *RawWords = IV->getValue().getRawData();
2003         for (unsigned i = 0; i != NWords; ++i) {
2004           emitSignedInt64(Record, RawWords[i]);
2005         }
2006         Code = bitc::CST_CODE_WIDE_INTEGER;
2007       }
2008     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2009       Code = bitc::CST_CODE_FLOAT;
2010       Type *Ty = CFP->getType();
2011       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
2012         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2013       } else if (Ty->isX86_FP80Ty()) {
2014         // api needed to prevent premature destruction
2015         // bits are not in the same order as a normal i80 APInt, compensate.
2016         APInt api = CFP->getValueAPF().bitcastToAPInt();
2017         const uint64_t *p = api.getRawData();
2018         Record.push_back((p[1] << 48) | (p[0] >> 16));
2019         Record.push_back(p[0] & 0xffffLL);
2020       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2021         APInt api = CFP->getValueAPF().bitcastToAPInt();
2022         const uint64_t *p = api.getRawData();
2023         Record.push_back(p[0]);
2024         Record.push_back(p[1]);
2025       } else {
2026         assert (0 && "Unknown FP type!");
2027       }
2028     } else if (isa<ConstantDataSequential>(C) &&
2029                cast<ConstantDataSequential>(C)->isString()) {
2030       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2031       // Emit constant strings specially.
2032       unsigned NumElts = Str->getNumElements();
2033       // If this is a null-terminated string, use the denser CSTRING encoding.
2034       if (Str->isCString()) {
2035         Code = bitc::CST_CODE_CSTRING;
2036         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2037       } else {
2038         Code = bitc::CST_CODE_STRING;
2039         AbbrevToUse = String8Abbrev;
2040       }
2041       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2042       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2043       for (unsigned i = 0; i != NumElts; ++i) {
2044         unsigned char V = Str->getElementAsInteger(i);
2045         Record.push_back(V);
2046         isCStr7 &= (V & 128) == 0;
2047         if (isCStrChar6)
2048           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2049       }
2050 
2051       if (isCStrChar6)
2052         AbbrevToUse = CString6Abbrev;
2053       else if (isCStr7)
2054         AbbrevToUse = CString7Abbrev;
2055     } else if (const ConstantDataSequential *CDS =
2056                   dyn_cast<ConstantDataSequential>(C)) {
2057       Code = bitc::CST_CODE_DATA;
2058       Type *EltTy = CDS->getType()->getElementType();
2059       if (isa<IntegerType>(EltTy)) {
2060         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2061           Record.push_back(CDS->getElementAsInteger(i));
2062       } else {
2063         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2064           Record.push_back(
2065               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2066       }
2067     } else if (isa<ConstantAggregate>(C)) {
2068       Code = bitc::CST_CODE_AGGREGATE;
2069       for (const Value *Op : C->operands())
2070         Record.push_back(VE.getValueID(Op));
2071       AbbrevToUse = AggregateAbbrev;
2072     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2073       switch (CE->getOpcode()) {
2074       default:
2075         if (Instruction::isCast(CE->getOpcode())) {
2076           Code = bitc::CST_CODE_CE_CAST;
2077           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2078           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2079           Record.push_back(VE.getValueID(C->getOperand(0)));
2080           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2081         } else {
2082           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2083           Code = bitc::CST_CODE_CE_BINOP;
2084           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2085           Record.push_back(VE.getValueID(C->getOperand(0)));
2086           Record.push_back(VE.getValueID(C->getOperand(1)));
2087           uint64_t Flags = getOptimizationFlags(CE);
2088           if (Flags != 0)
2089             Record.push_back(Flags);
2090         }
2091         break;
2092       case Instruction::GetElementPtr: {
2093         Code = bitc::CST_CODE_CE_GEP;
2094         const auto *GO = cast<GEPOperator>(C);
2095         if (GO->isInBounds())
2096           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2097         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2098         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2099           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2100           Record.push_back(VE.getValueID(C->getOperand(i)));
2101         }
2102         break;
2103       }
2104       case Instruction::Select:
2105         Code = bitc::CST_CODE_CE_SELECT;
2106         Record.push_back(VE.getValueID(C->getOperand(0)));
2107         Record.push_back(VE.getValueID(C->getOperand(1)));
2108         Record.push_back(VE.getValueID(C->getOperand(2)));
2109         break;
2110       case Instruction::ExtractElement:
2111         Code = bitc::CST_CODE_CE_EXTRACTELT;
2112         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2113         Record.push_back(VE.getValueID(C->getOperand(0)));
2114         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2115         Record.push_back(VE.getValueID(C->getOperand(1)));
2116         break;
2117       case Instruction::InsertElement:
2118         Code = bitc::CST_CODE_CE_INSERTELT;
2119         Record.push_back(VE.getValueID(C->getOperand(0)));
2120         Record.push_back(VE.getValueID(C->getOperand(1)));
2121         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2122         Record.push_back(VE.getValueID(C->getOperand(2)));
2123         break;
2124       case Instruction::ShuffleVector:
2125         // If the return type and argument types are the same, this is a
2126         // standard shufflevector instruction.  If the types are different,
2127         // then the shuffle is widening or truncating the input vectors, and
2128         // the argument type must also be encoded.
2129         if (C->getType() == C->getOperand(0)->getType()) {
2130           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2131         } else {
2132           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2133           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2134         }
2135         Record.push_back(VE.getValueID(C->getOperand(0)));
2136         Record.push_back(VE.getValueID(C->getOperand(1)));
2137         Record.push_back(VE.getValueID(C->getOperand(2)));
2138         break;
2139       case Instruction::ICmp:
2140       case Instruction::FCmp:
2141         Code = bitc::CST_CODE_CE_CMP;
2142         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2143         Record.push_back(VE.getValueID(C->getOperand(0)));
2144         Record.push_back(VE.getValueID(C->getOperand(1)));
2145         Record.push_back(CE->getPredicate());
2146         break;
2147       }
2148     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2149       Code = bitc::CST_CODE_BLOCKADDRESS;
2150       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2151       Record.push_back(VE.getValueID(BA->getFunction()));
2152       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2153     } else {
2154 #ifndef NDEBUG
2155       C->dump();
2156 #endif
2157       llvm_unreachable("Unknown constant!");
2158     }
2159     Stream.EmitRecord(Code, Record, AbbrevToUse);
2160     Record.clear();
2161   }
2162 
2163   Stream.ExitBlock();
2164 }
2165 
2166 void ModuleBitcodeWriter::writeModuleConstants() {
2167   const ValueEnumerator::ValueList &Vals = VE.getValues();
2168 
2169   // Find the first constant to emit, which is the first non-globalvalue value.
2170   // We know globalvalues have been emitted by WriteModuleInfo.
2171   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2172     if (!isa<GlobalValue>(Vals[i].first)) {
2173       writeConstants(i, Vals.size(), true);
2174       return;
2175     }
2176   }
2177 }
2178 
2179 /// pushValueAndType - The file has to encode both the value and type id for
2180 /// many values, because we need to know what type to create for forward
2181 /// references.  However, most operands are not forward references, so this type
2182 /// field is not needed.
2183 ///
2184 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2185 /// instruction ID, then it is a forward reference, and it also includes the
2186 /// type ID.  The value ID that is written is encoded relative to the InstID.
2187 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2188                                            SmallVectorImpl<unsigned> &Vals) {
2189   unsigned ValID = VE.getValueID(V);
2190   // Make encoding relative to the InstID.
2191   Vals.push_back(InstID - ValID);
2192   if (ValID >= InstID) {
2193     Vals.push_back(VE.getTypeID(V->getType()));
2194     return true;
2195   }
2196   return false;
2197 }
2198 
2199 void ModuleBitcodeWriter::writeOperandBundles(ImmutableCallSite CS,
2200                                               unsigned InstID) {
2201   SmallVector<unsigned, 64> Record;
2202   LLVMContext &C = CS.getInstruction()->getContext();
2203 
2204   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2205     const auto &Bundle = CS.getOperandBundleAt(i);
2206     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2207 
2208     for (auto &Input : Bundle.Inputs)
2209       pushValueAndType(Input, InstID, Record);
2210 
2211     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2212     Record.clear();
2213   }
2214 }
2215 
2216 /// pushValue - Like pushValueAndType, but where the type of the value is
2217 /// omitted (perhaps it was already encoded in an earlier operand).
2218 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2219                                     SmallVectorImpl<unsigned> &Vals) {
2220   unsigned ValID = VE.getValueID(V);
2221   Vals.push_back(InstID - ValID);
2222 }
2223 
2224 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2225                                           SmallVectorImpl<uint64_t> &Vals) {
2226   unsigned ValID = VE.getValueID(V);
2227   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2228   emitSignedInt64(Vals, diff);
2229 }
2230 
2231 /// WriteInstruction - Emit an instruction to the specified stream.
2232 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2233                                            unsigned InstID,
2234                                            SmallVectorImpl<unsigned> &Vals) {
2235   unsigned Code = 0;
2236   unsigned AbbrevToUse = 0;
2237   VE.setInstructionID(&I);
2238   switch (I.getOpcode()) {
2239   default:
2240     if (Instruction::isCast(I.getOpcode())) {
2241       Code = bitc::FUNC_CODE_INST_CAST;
2242       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2243         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2244       Vals.push_back(VE.getTypeID(I.getType()));
2245       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2246     } else {
2247       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2248       Code = bitc::FUNC_CODE_INST_BINOP;
2249       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2250         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2251       pushValue(I.getOperand(1), InstID, Vals);
2252       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2253       uint64_t Flags = getOptimizationFlags(&I);
2254       if (Flags != 0) {
2255         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2256           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2257         Vals.push_back(Flags);
2258       }
2259     }
2260     break;
2261 
2262   case Instruction::GetElementPtr: {
2263     Code = bitc::FUNC_CODE_INST_GEP;
2264     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2265     auto &GEPInst = cast<GetElementPtrInst>(I);
2266     Vals.push_back(GEPInst.isInBounds());
2267     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2268     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2269       pushValueAndType(I.getOperand(i), InstID, Vals);
2270     break;
2271   }
2272   case Instruction::ExtractValue: {
2273     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2274     pushValueAndType(I.getOperand(0), InstID, Vals);
2275     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2276     Vals.append(EVI->idx_begin(), EVI->idx_end());
2277     break;
2278   }
2279   case Instruction::InsertValue: {
2280     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2281     pushValueAndType(I.getOperand(0), InstID, Vals);
2282     pushValueAndType(I.getOperand(1), InstID, Vals);
2283     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2284     Vals.append(IVI->idx_begin(), IVI->idx_end());
2285     break;
2286   }
2287   case Instruction::Select:
2288     Code = bitc::FUNC_CODE_INST_VSELECT;
2289     pushValueAndType(I.getOperand(1), InstID, Vals);
2290     pushValue(I.getOperand(2), InstID, Vals);
2291     pushValueAndType(I.getOperand(0), InstID, Vals);
2292     break;
2293   case Instruction::ExtractElement:
2294     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2295     pushValueAndType(I.getOperand(0), InstID, Vals);
2296     pushValueAndType(I.getOperand(1), InstID, Vals);
2297     break;
2298   case Instruction::InsertElement:
2299     Code = bitc::FUNC_CODE_INST_INSERTELT;
2300     pushValueAndType(I.getOperand(0), InstID, Vals);
2301     pushValue(I.getOperand(1), InstID, Vals);
2302     pushValueAndType(I.getOperand(2), InstID, Vals);
2303     break;
2304   case Instruction::ShuffleVector:
2305     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2306     pushValueAndType(I.getOperand(0), InstID, Vals);
2307     pushValue(I.getOperand(1), InstID, Vals);
2308     pushValue(I.getOperand(2), InstID, Vals);
2309     break;
2310   case Instruction::ICmp:
2311   case Instruction::FCmp: {
2312     // compare returning Int1Ty or vector of Int1Ty
2313     Code = bitc::FUNC_CODE_INST_CMP2;
2314     pushValueAndType(I.getOperand(0), InstID, Vals);
2315     pushValue(I.getOperand(1), InstID, Vals);
2316     Vals.push_back(cast<CmpInst>(I).getPredicate());
2317     uint64_t Flags = getOptimizationFlags(&I);
2318     if (Flags != 0)
2319       Vals.push_back(Flags);
2320     break;
2321   }
2322 
2323   case Instruction::Ret:
2324     {
2325       Code = bitc::FUNC_CODE_INST_RET;
2326       unsigned NumOperands = I.getNumOperands();
2327       if (NumOperands == 0)
2328         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2329       else if (NumOperands == 1) {
2330         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2331           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2332       } else {
2333         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2334           pushValueAndType(I.getOperand(i), InstID, Vals);
2335       }
2336     }
2337     break;
2338   case Instruction::Br:
2339     {
2340       Code = bitc::FUNC_CODE_INST_BR;
2341       const BranchInst &II = cast<BranchInst>(I);
2342       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2343       if (II.isConditional()) {
2344         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2345         pushValue(II.getCondition(), InstID, Vals);
2346       }
2347     }
2348     break;
2349   case Instruction::Switch:
2350     {
2351       Code = bitc::FUNC_CODE_INST_SWITCH;
2352       const SwitchInst &SI = cast<SwitchInst>(I);
2353       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2354       pushValue(SI.getCondition(), InstID, Vals);
2355       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2356       for (SwitchInst::ConstCaseIt Case : SI.cases()) {
2357         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2358         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2359       }
2360     }
2361     break;
2362   case Instruction::IndirectBr:
2363     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2364     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2365     // Encode the address operand as relative, but not the basic blocks.
2366     pushValue(I.getOperand(0), InstID, Vals);
2367     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2368       Vals.push_back(VE.getValueID(I.getOperand(i)));
2369     break;
2370 
2371   case Instruction::Invoke: {
2372     const InvokeInst *II = cast<InvokeInst>(&I);
2373     const Value *Callee = II->getCalledValue();
2374     FunctionType *FTy = II->getFunctionType();
2375 
2376     if (II->hasOperandBundles())
2377       writeOperandBundles(II, InstID);
2378 
2379     Code = bitc::FUNC_CODE_INST_INVOKE;
2380 
2381     Vals.push_back(VE.getAttributeID(II->getAttributes()));
2382     Vals.push_back(II->getCallingConv() | 1 << 13);
2383     Vals.push_back(VE.getValueID(II->getNormalDest()));
2384     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2385     Vals.push_back(VE.getTypeID(FTy));
2386     pushValueAndType(Callee, InstID, Vals);
2387 
2388     // Emit value #'s for the fixed parameters.
2389     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2390       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2391 
2392     // Emit type/value pairs for varargs params.
2393     if (FTy->isVarArg()) {
2394       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
2395            i != e; ++i)
2396         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2397     }
2398     break;
2399   }
2400   case Instruction::Resume:
2401     Code = bitc::FUNC_CODE_INST_RESUME;
2402     pushValueAndType(I.getOperand(0), InstID, Vals);
2403     break;
2404   case Instruction::CleanupRet: {
2405     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2406     const auto &CRI = cast<CleanupReturnInst>(I);
2407     pushValue(CRI.getCleanupPad(), InstID, Vals);
2408     if (CRI.hasUnwindDest())
2409       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2410     break;
2411   }
2412   case Instruction::CatchRet: {
2413     Code = bitc::FUNC_CODE_INST_CATCHRET;
2414     const auto &CRI = cast<CatchReturnInst>(I);
2415     pushValue(CRI.getCatchPad(), InstID, Vals);
2416     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2417     break;
2418   }
2419   case Instruction::CleanupPad:
2420   case Instruction::CatchPad: {
2421     const auto &FuncletPad = cast<FuncletPadInst>(I);
2422     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2423                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2424     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2425 
2426     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2427     Vals.push_back(NumArgOperands);
2428     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2429       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2430     break;
2431   }
2432   case Instruction::CatchSwitch: {
2433     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2434     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2435 
2436     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2437 
2438     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2439     Vals.push_back(NumHandlers);
2440     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2441       Vals.push_back(VE.getValueID(CatchPadBB));
2442 
2443     if (CatchSwitch.hasUnwindDest())
2444       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
2445     break;
2446   }
2447   case Instruction::Unreachable:
2448     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
2449     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
2450     break;
2451 
2452   case Instruction::PHI: {
2453     const PHINode &PN = cast<PHINode>(I);
2454     Code = bitc::FUNC_CODE_INST_PHI;
2455     // With the newer instruction encoding, forward references could give
2456     // negative valued IDs.  This is most common for PHIs, so we use
2457     // signed VBRs.
2458     SmallVector<uint64_t, 128> Vals64;
2459     Vals64.push_back(VE.getTypeID(PN.getType()));
2460     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
2461       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
2462       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
2463     }
2464     // Emit a Vals64 vector and exit.
2465     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
2466     Vals64.clear();
2467     return;
2468   }
2469 
2470   case Instruction::LandingPad: {
2471     const LandingPadInst &LP = cast<LandingPadInst>(I);
2472     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
2473     Vals.push_back(VE.getTypeID(LP.getType()));
2474     Vals.push_back(LP.isCleanup());
2475     Vals.push_back(LP.getNumClauses());
2476     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
2477       if (LP.isCatch(I))
2478         Vals.push_back(LandingPadInst::Catch);
2479       else
2480         Vals.push_back(LandingPadInst::Filter);
2481       pushValueAndType(LP.getClause(I), InstID, Vals);
2482     }
2483     break;
2484   }
2485 
2486   case Instruction::Alloca: {
2487     Code = bitc::FUNC_CODE_INST_ALLOCA;
2488     const AllocaInst &AI = cast<AllocaInst>(I);
2489     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
2490     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2491     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
2492     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
2493     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
2494            "not enough bits for maximum alignment");
2495     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
2496     AlignRecord |= AI.isUsedWithInAlloca() << 5;
2497     AlignRecord |= 1 << 6;
2498     AlignRecord |= AI.isSwiftError() << 7;
2499     Vals.push_back(AlignRecord);
2500     break;
2501   }
2502 
2503   case Instruction::Load:
2504     if (cast<LoadInst>(I).isAtomic()) {
2505       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
2506       pushValueAndType(I.getOperand(0), InstID, Vals);
2507     } else {
2508       Code = bitc::FUNC_CODE_INST_LOAD;
2509       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
2510         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
2511     }
2512     Vals.push_back(VE.getTypeID(I.getType()));
2513     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
2514     Vals.push_back(cast<LoadInst>(I).isVolatile());
2515     if (cast<LoadInst>(I).isAtomic()) {
2516       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
2517       Vals.push_back(getEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
2518     }
2519     break;
2520   case Instruction::Store:
2521     if (cast<StoreInst>(I).isAtomic())
2522       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
2523     else
2524       Code = bitc::FUNC_CODE_INST_STORE;
2525     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
2526     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
2527     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
2528     Vals.push_back(cast<StoreInst>(I).isVolatile());
2529     if (cast<StoreInst>(I).isAtomic()) {
2530       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
2531       Vals.push_back(getEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
2532     }
2533     break;
2534   case Instruction::AtomicCmpXchg:
2535     Code = bitc::FUNC_CODE_INST_CMPXCHG;
2536     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
2537     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
2538     pushValue(I.getOperand(2), InstID, Vals);        // newval.
2539     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
2540     Vals.push_back(
2541         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
2542     Vals.push_back(
2543         getEncodedSynchScope(cast<AtomicCmpXchgInst>(I).getSynchScope()));
2544     Vals.push_back(
2545         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
2546     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
2547     break;
2548   case Instruction::AtomicRMW:
2549     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
2550     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
2551     pushValue(I.getOperand(1), InstID, Vals);        // val.
2552     Vals.push_back(
2553         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
2554     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
2555     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
2556     Vals.push_back(
2557         getEncodedSynchScope(cast<AtomicRMWInst>(I).getSynchScope()));
2558     break;
2559   case Instruction::Fence:
2560     Code = bitc::FUNC_CODE_INST_FENCE;
2561     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
2562     Vals.push_back(getEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
2563     break;
2564   case Instruction::Call: {
2565     const CallInst &CI = cast<CallInst>(I);
2566     FunctionType *FTy = CI.getFunctionType();
2567 
2568     if (CI.hasOperandBundles())
2569       writeOperandBundles(&CI, InstID);
2570 
2571     Code = bitc::FUNC_CODE_INST_CALL;
2572 
2573     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
2574 
2575     unsigned Flags = getOptimizationFlags(&I);
2576     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
2577                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
2578                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
2579                    1 << bitc::CALL_EXPLICIT_TYPE |
2580                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
2581                    unsigned(Flags != 0) << bitc::CALL_FMF);
2582     if (Flags != 0)
2583       Vals.push_back(Flags);
2584 
2585     Vals.push_back(VE.getTypeID(FTy));
2586     pushValueAndType(CI.getCalledValue(), InstID, Vals); // Callee
2587 
2588     // Emit value #'s for the fixed parameters.
2589     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
2590       // Check for labels (can happen with asm labels).
2591       if (FTy->getParamType(i)->isLabelTy())
2592         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
2593       else
2594         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
2595     }
2596 
2597     // Emit type/value pairs for varargs params.
2598     if (FTy->isVarArg()) {
2599       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
2600            i != e; ++i)
2601         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
2602     }
2603     break;
2604   }
2605   case Instruction::VAArg:
2606     Code = bitc::FUNC_CODE_INST_VAARG;
2607     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
2608     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
2609     Vals.push_back(VE.getTypeID(I.getType())); // restype.
2610     break;
2611   }
2612 
2613   Stream.EmitRecord(Code, Vals, AbbrevToUse);
2614   Vals.clear();
2615 }
2616 
2617 /// Emit names for globals/functions etc. \p IsModuleLevel is true when
2618 /// we are writing the module-level VST, where we are including a function
2619 /// bitcode index and need to backpatch the VST forward declaration record.
2620 void ModuleBitcodeWriter::writeValueSymbolTable(
2621     const ValueSymbolTable &VST, bool IsModuleLevel,
2622     DenseMap<const Function *, uint64_t> *FunctionToBitcodeIndex) {
2623   if (VST.empty()) {
2624     // writeValueSymbolTableForwardDecl should have returned early as
2625     // well. Ensure this handling remains in sync by asserting that
2626     // the placeholder offset is not set.
2627     assert(!IsModuleLevel || !hasVSTOffsetPlaceholder());
2628     return;
2629   }
2630 
2631   if (IsModuleLevel && hasVSTOffsetPlaceholder()) {
2632     // Get the offset of the VST we are writing, and backpatch it into
2633     // the VST forward declaration record.
2634     uint64_t VSTOffset = Stream.GetCurrentBitNo();
2635     // The BitcodeStartBit was the stream offset of the actual bitcode
2636     // (e.g. excluding any initial darwin header).
2637     VSTOffset -= bitcodeStartBit();
2638     assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
2639     Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32);
2640   }
2641 
2642   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
2643 
2644   // For the module-level VST, add abbrev Ids for the VST_CODE_FNENTRY
2645   // records, which are not used in the per-function VSTs.
2646   unsigned FnEntry8BitAbbrev;
2647   unsigned FnEntry7BitAbbrev;
2648   unsigned FnEntry6BitAbbrev;
2649   if (IsModuleLevel && hasVSTOffsetPlaceholder()) {
2650     // 8-bit fixed-width VST_CODE_FNENTRY function strings.
2651     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2652     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2653     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2654     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2655     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2656     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2657     FnEntry8BitAbbrev = Stream.EmitAbbrev(Abbv);
2658 
2659     // 7-bit fixed width VST_CODE_FNENTRY function strings.
2660     Abbv = new BitCodeAbbrev();
2661     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2662     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2663     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2664     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2665     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2666     FnEntry7BitAbbrev = Stream.EmitAbbrev(Abbv);
2667 
2668     // 6-bit char6 VST_CODE_FNENTRY function strings.
2669     Abbv = new BitCodeAbbrev();
2670     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2671     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2672     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2673     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2674     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2675     FnEntry6BitAbbrev = Stream.EmitAbbrev(Abbv);
2676   }
2677 
2678   // FIXME: Set up the abbrev, we know how many values there are!
2679   // FIXME: We know if the type names can use 7-bit ascii.
2680   SmallVector<unsigned, 64> NameVals;
2681 
2682   for (const ValueName &Name : VST) {
2683     // Figure out the encoding to use for the name.
2684     StringEncoding Bits =
2685         getStringEncoding(Name.getKeyData(), Name.getKeyLength());
2686 
2687     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
2688     NameVals.push_back(VE.getValueID(Name.getValue()));
2689 
2690     Function *F = dyn_cast<Function>(Name.getValue());
2691     if (!F) {
2692       // If value is an alias, need to get the aliased base object to
2693       // see if it is a function.
2694       auto *GA = dyn_cast<GlobalAlias>(Name.getValue());
2695       if (GA && GA->getBaseObject())
2696         F = dyn_cast<Function>(GA->getBaseObject());
2697     }
2698 
2699     // VST_CODE_ENTRY:   [valueid, namechar x N]
2700     // VST_CODE_FNENTRY: [valueid, funcoffset, namechar x N]
2701     // VST_CODE_BBENTRY: [bbid, namechar x N]
2702     unsigned Code;
2703     if (isa<BasicBlock>(Name.getValue())) {
2704       Code = bitc::VST_CODE_BBENTRY;
2705       if (Bits == SE_Char6)
2706         AbbrevToUse = VST_BBENTRY_6_ABBREV;
2707     } else if (F && !F->isDeclaration()) {
2708       // Must be the module-level VST, where we pass in the Index and
2709       // have a VSTOffsetPlaceholder. The function-level VST should not
2710       // contain any Function symbols.
2711       assert(FunctionToBitcodeIndex);
2712       assert(hasVSTOffsetPlaceholder());
2713 
2714       // Save the word offset of the function (from the start of the
2715       // actual bitcode written to the stream).
2716       uint64_t BitcodeIndex = (*FunctionToBitcodeIndex)[F] - bitcodeStartBit();
2717       assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
2718       NameVals.push_back(BitcodeIndex / 32);
2719 
2720       Code = bitc::VST_CODE_FNENTRY;
2721       AbbrevToUse = FnEntry8BitAbbrev;
2722       if (Bits == SE_Char6)
2723         AbbrevToUse = FnEntry6BitAbbrev;
2724       else if (Bits == SE_Fixed7)
2725         AbbrevToUse = FnEntry7BitAbbrev;
2726     } else {
2727       Code = bitc::VST_CODE_ENTRY;
2728       if (Bits == SE_Char6)
2729         AbbrevToUse = VST_ENTRY_6_ABBREV;
2730       else if (Bits == SE_Fixed7)
2731         AbbrevToUse = VST_ENTRY_7_ABBREV;
2732     }
2733 
2734     for (const auto P : Name.getKey())
2735       NameVals.push_back((unsigned char)P);
2736 
2737     // Emit the finished record.
2738     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
2739     NameVals.clear();
2740   }
2741   Stream.ExitBlock();
2742 }
2743 
2744 /// Emit function names and summary offsets for the combined index
2745 /// used by ThinLTO.
2746 void IndexBitcodeWriter::writeCombinedValueSymbolTable() {
2747   assert(hasVSTOffsetPlaceholder() && "Expected non-zero VSTOffsetPlaceholder");
2748   // Get the offset of the VST we are writing, and backpatch it into
2749   // the VST forward declaration record.
2750   uint64_t VSTOffset = Stream.GetCurrentBitNo();
2751   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
2752   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32);
2753 
2754   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
2755 
2756   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2757   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_COMBINED_ENTRY));
2758   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
2759   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // refguid
2760   unsigned EntryAbbrev = Stream.EmitAbbrev(Abbv);
2761 
2762   SmallVector<uint64_t, 64> NameVals;
2763   for (const auto &GVI : valueIds()) {
2764     // VST_CODE_COMBINED_ENTRY: [valueid, refguid]
2765     NameVals.push_back(GVI.second);
2766     NameVals.push_back(GVI.first);
2767 
2768     // Emit the finished record.
2769     Stream.EmitRecord(bitc::VST_CODE_COMBINED_ENTRY, NameVals, EntryAbbrev);
2770     NameVals.clear();
2771   }
2772   Stream.ExitBlock();
2773 }
2774 
2775 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
2776   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
2777   unsigned Code;
2778   if (isa<BasicBlock>(Order.V))
2779     Code = bitc::USELIST_CODE_BB;
2780   else
2781     Code = bitc::USELIST_CODE_DEFAULT;
2782 
2783   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
2784   Record.push_back(VE.getValueID(Order.V));
2785   Stream.EmitRecord(Code, Record);
2786 }
2787 
2788 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
2789   assert(VE.shouldPreserveUseListOrder() &&
2790          "Expected to be preserving use-list order");
2791 
2792   auto hasMore = [&]() {
2793     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
2794   };
2795   if (!hasMore())
2796     // Nothing to do.
2797     return;
2798 
2799   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
2800   while (hasMore()) {
2801     writeUseList(std::move(VE.UseListOrders.back()));
2802     VE.UseListOrders.pop_back();
2803   }
2804   Stream.ExitBlock();
2805 }
2806 
2807 /// Emit a function body to the module stream.
2808 void ModuleBitcodeWriter::writeFunction(
2809     const Function &F,
2810     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
2811   // Save the bitcode index of the start of this function block for recording
2812   // in the VST.
2813   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
2814 
2815   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
2816   VE.incorporateFunction(F);
2817 
2818   SmallVector<unsigned, 64> Vals;
2819 
2820   // Emit the number of basic blocks, so the reader can create them ahead of
2821   // time.
2822   Vals.push_back(VE.getBasicBlocks().size());
2823   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
2824   Vals.clear();
2825 
2826   // If there are function-local constants, emit them now.
2827   unsigned CstStart, CstEnd;
2828   VE.getFunctionConstantRange(CstStart, CstEnd);
2829   writeConstants(CstStart, CstEnd, false);
2830 
2831   // If there is function-local metadata, emit it now.
2832   writeFunctionMetadata(F);
2833 
2834   // Keep a running idea of what the instruction ID is.
2835   unsigned InstID = CstEnd;
2836 
2837   bool NeedsMetadataAttachment = F.hasMetadata();
2838 
2839   DILocation *LastDL = nullptr;
2840   // Finally, emit all the instructions, in order.
2841   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
2842     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
2843          I != E; ++I) {
2844       writeInstruction(*I, InstID, Vals);
2845 
2846       if (!I->getType()->isVoidTy())
2847         ++InstID;
2848 
2849       // If the instruction has metadata, write a metadata attachment later.
2850       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
2851 
2852       // If the instruction has a debug location, emit it.
2853       DILocation *DL = I->getDebugLoc();
2854       if (!DL)
2855         continue;
2856 
2857       if (DL == LastDL) {
2858         // Just repeat the same debug loc as last time.
2859         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
2860         continue;
2861       }
2862 
2863       Vals.push_back(DL->getLine());
2864       Vals.push_back(DL->getColumn());
2865       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
2866       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
2867       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
2868       Vals.clear();
2869 
2870       LastDL = DL;
2871     }
2872 
2873   // Emit names for all the instructions etc.
2874   writeValueSymbolTable(F.getValueSymbolTable());
2875 
2876   if (NeedsMetadataAttachment)
2877     writeMetadataAttachment(F);
2878   if (VE.shouldPreserveUseListOrder())
2879     writeUseListBlock(&F);
2880   VE.purgeFunction();
2881   Stream.ExitBlock();
2882 }
2883 
2884 // Emit blockinfo, which defines the standard abbreviations etc.
2885 void ModuleBitcodeWriter::writeBlockInfo() {
2886   // We only want to emit block info records for blocks that have multiple
2887   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
2888   // Other blocks can define their abbrevs inline.
2889   Stream.EnterBlockInfoBlock(2);
2890 
2891   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
2892     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2893     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
2894     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2895     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2896     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2897     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
2898         VST_ENTRY_8_ABBREV)
2899       llvm_unreachable("Unexpected abbrev ordering!");
2900   }
2901 
2902   { // 7-bit fixed width VST_CODE_ENTRY strings.
2903     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2904     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2905     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2906     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2907     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2908     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
2909         VST_ENTRY_7_ABBREV)
2910       llvm_unreachable("Unexpected abbrev ordering!");
2911   }
2912   { // 6-bit char6 VST_CODE_ENTRY strings.
2913     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2914     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2915     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2916     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2917     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2918     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
2919         VST_ENTRY_6_ABBREV)
2920       llvm_unreachable("Unexpected abbrev ordering!");
2921   }
2922   { // 6-bit char6 VST_CODE_BBENTRY strings.
2923     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2924     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
2925     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2926     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2927     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2928     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
2929         VST_BBENTRY_6_ABBREV)
2930       llvm_unreachable("Unexpected abbrev ordering!");
2931   }
2932 
2933 
2934 
2935   { // SETTYPE abbrev for CONSTANTS_BLOCK.
2936     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2937     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
2938     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
2939                               VE.computeBitsRequiredForTypeIndicies()));
2940     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
2941         CONSTANTS_SETTYPE_ABBREV)
2942       llvm_unreachable("Unexpected abbrev ordering!");
2943   }
2944 
2945   { // INTEGER abbrev for CONSTANTS_BLOCK.
2946     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2947     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
2948     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2949     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
2950         CONSTANTS_INTEGER_ABBREV)
2951       llvm_unreachable("Unexpected abbrev ordering!");
2952   }
2953 
2954   { // CE_CAST abbrev for CONSTANTS_BLOCK.
2955     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2956     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
2957     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
2958     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
2959                               VE.computeBitsRequiredForTypeIndicies()));
2960     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
2961 
2962     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
2963         CONSTANTS_CE_CAST_Abbrev)
2964       llvm_unreachable("Unexpected abbrev ordering!");
2965   }
2966   { // NULL abbrev for CONSTANTS_BLOCK.
2967     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2968     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
2969     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
2970         CONSTANTS_NULL_Abbrev)
2971       llvm_unreachable("Unexpected abbrev ordering!");
2972   }
2973 
2974   // FIXME: This should only use space for first class types!
2975 
2976   { // INST_LOAD abbrev for FUNCTION_BLOCK.
2977     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2978     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
2979     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
2980     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
2981                               VE.computeBitsRequiredForTypeIndicies()));
2982     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
2983     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
2984     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2985         FUNCTION_INST_LOAD_ABBREV)
2986       llvm_unreachable("Unexpected abbrev ordering!");
2987   }
2988   { // INST_BINOP abbrev for FUNCTION_BLOCK.
2989     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2990     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2991     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2992     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2993     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2994     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2995         FUNCTION_INST_BINOP_ABBREV)
2996       llvm_unreachable("Unexpected abbrev ordering!");
2997   }
2998   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
2999     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3000     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3001     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3002     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3003     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3004     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
3005     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3006         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3007       llvm_unreachable("Unexpected abbrev ordering!");
3008   }
3009   { // INST_CAST abbrev for FUNCTION_BLOCK.
3010     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3011     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3012     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3013     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3014                               VE.computeBitsRequiredForTypeIndicies()));
3015     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3016     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3017         FUNCTION_INST_CAST_ABBREV)
3018       llvm_unreachable("Unexpected abbrev ordering!");
3019   }
3020 
3021   { // INST_RET abbrev for FUNCTION_BLOCK.
3022     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3023     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3024     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3025         FUNCTION_INST_RET_VOID_ABBREV)
3026       llvm_unreachable("Unexpected abbrev ordering!");
3027   }
3028   { // INST_RET abbrev for FUNCTION_BLOCK.
3029     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3030     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3031     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3032     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3033         FUNCTION_INST_RET_VAL_ABBREV)
3034       llvm_unreachable("Unexpected abbrev ordering!");
3035   }
3036   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3037     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3038     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3039     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3040         FUNCTION_INST_UNREACHABLE_ABBREV)
3041       llvm_unreachable("Unexpected abbrev ordering!");
3042   }
3043   {
3044     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3045     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3046     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3047     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3048                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3049     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3050     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3051     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3052         FUNCTION_INST_GEP_ABBREV)
3053       llvm_unreachable("Unexpected abbrev ordering!");
3054   }
3055 
3056   Stream.ExitBlock();
3057 }
3058 
3059 /// Write the module path strings, currently only used when generating
3060 /// a combined index file.
3061 void IndexBitcodeWriter::writeModStrings() {
3062   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3063 
3064   // TODO: See which abbrev sizes we actually need to emit
3065 
3066   // 8-bit fixed-width MST_ENTRY strings.
3067   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3068   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3069   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3070   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3071   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3072   unsigned Abbrev8Bit = Stream.EmitAbbrev(Abbv);
3073 
3074   // 7-bit fixed width MST_ENTRY strings.
3075   Abbv = new BitCodeAbbrev();
3076   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3077   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3078   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3079   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3080   unsigned Abbrev7Bit = Stream.EmitAbbrev(Abbv);
3081 
3082   // 6-bit char6 MST_ENTRY strings.
3083   Abbv = new BitCodeAbbrev();
3084   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3085   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3086   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3087   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3088   unsigned Abbrev6Bit = Stream.EmitAbbrev(Abbv);
3089 
3090   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3091   Abbv = new BitCodeAbbrev();
3092   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3093   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3094   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3095   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3096   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3097   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3098   unsigned AbbrevHash = Stream.EmitAbbrev(Abbv);
3099 
3100   SmallVector<unsigned, 64> Vals;
3101   for (const auto &MPSE : Index.modulePaths()) {
3102     if (!doIncludeModule(MPSE.getKey()))
3103       continue;
3104     StringEncoding Bits =
3105         getStringEncoding(MPSE.getKey().data(), MPSE.getKey().size());
3106     unsigned AbbrevToUse = Abbrev8Bit;
3107     if (Bits == SE_Char6)
3108       AbbrevToUse = Abbrev6Bit;
3109     else if (Bits == SE_Fixed7)
3110       AbbrevToUse = Abbrev7Bit;
3111 
3112     Vals.push_back(MPSE.getValue().first);
3113 
3114     for (const auto P : MPSE.getKey())
3115       Vals.push_back((unsigned char)P);
3116 
3117     // Emit the finished record.
3118     Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3119 
3120     Vals.clear();
3121     // Emit an optional hash for the module now
3122     auto &Hash = MPSE.getValue().second;
3123     bool AllZero = true; // Detect if the hash is empty, and do not generate it
3124     for (auto Val : Hash) {
3125       if (Val)
3126         AllZero = false;
3127       Vals.push_back(Val);
3128     }
3129     if (!AllZero) {
3130       // Emit the hash record.
3131       Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3132     }
3133 
3134     Vals.clear();
3135   }
3136   Stream.ExitBlock();
3137 }
3138 
3139 // Helper to emit a single function summary record.
3140 void ModuleBitcodeWriter::writePerModuleFunctionSummaryRecord(
3141     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3142     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3143     const Function &F) {
3144   NameVals.push_back(ValueID);
3145 
3146   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3147   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3148   NameVals.push_back(FS->instCount());
3149   NameVals.push_back(FS->refs().size());
3150 
3151   for (auto &RI : FS->refs())
3152     NameVals.push_back(VE.getValueID(RI.getValue()));
3153 
3154   bool HasProfileData = F.getEntryCount().hasValue();
3155   for (auto &ECI : FS->calls()) {
3156     NameVals.push_back(VE.getValueID(ECI.first.getValue()));
3157     assert(ECI.second.CallsiteCount > 0 && "Expected at least one callsite");
3158     NameVals.push_back(ECI.second.CallsiteCount);
3159     if (HasProfileData)
3160       NameVals.push_back(ECI.second.ProfileCount);
3161   }
3162 
3163   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3164   unsigned Code =
3165       (HasProfileData ? bitc::FS_PERMODULE_PROFILE : bitc::FS_PERMODULE);
3166 
3167   // Emit the finished record.
3168   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3169   NameVals.clear();
3170 }
3171 
3172 // Collect the global value references in the given variable's initializer,
3173 // and emit them in a summary record.
3174 void ModuleBitcodeWriter::writeModuleLevelReferences(
3175     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3176     unsigned FSModRefsAbbrev) {
3177   // Only interested in recording variable defs in the summary.
3178   if (V.isDeclaration())
3179     return;
3180   NameVals.push_back(VE.getValueID(&V));
3181   NameVals.push_back(getEncodedGVSummaryFlags(V));
3182   auto *Summary = Index->getGlobalValueSummary(V);
3183   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
3184   for (auto Ref : VS->refs())
3185     NameVals.push_back(VE.getValueID(Ref.getValue()));
3186   Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3187                     FSModRefsAbbrev);
3188   NameVals.clear();
3189 }
3190 
3191 // Current version for the summary.
3192 // This is bumped whenever we introduce changes in the way some record are
3193 // interpreted, like flags for instance.
3194 static const uint64_t INDEX_VERSION = 1;
3195 
3196 /// Emit the per-module summary section alongside the rest of
3197 /// the module's bitcode.
3198 void ModuleBitcodeWriter::writePerModuleGlobalValueSummary() {
3199   if (M.empty())
3200     return;
3201 
3202   if (Index->begin() == Index->end())
3203     return;
3204 
3205   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 4);
3206 
3207   Stream.EmitRecord(bitc::FS_VERSION, ArrayRef<uint64_t>{INDEX_VERSION});
3208 
3209   // Abbrev for FS_PERMODULE.
3210   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3211   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
3212   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3213   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3214   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3215   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3216   // numrefs x valueid, n x (valueid, callsitecount)
3217   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3218   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3219   unsigned FSCallsAbbrev = Stream.EmitAbbrev(Abbv);
3220 
3221   // Abbrev for FS_PERMODULE_PROFILE.
3222   Abbv = new BitCodeAbbrev();
3223   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
3224   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3225   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3226   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3227   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3228   // numrefs x valueid, n x (valueid, callsitecount, profilecount)
3229   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3230   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3231   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(Abbv);
3232 
3233   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
3234   Abbv = new BitCodeAbbrev();
3235   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
3236   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3237   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3238   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
3239   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3240   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(Abbv);
3241 
3242   // Abbrev for FS_ALIAS.
3243   Abbv = new BitCodeAbbrev();
3244   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
3245   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3246   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3247   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3248   unsigned FSAliasAbbrev = Stream.EmitAbbrev(Abbv);
3249 
3250   SmallVector<uint64_t, 64> NameVals;
3251   // Iterate over the list of functions instead of the Index to
3252   // ensure the ordering is stable.
3253   for (const Function &F : M) {
3254     if (F.isDeclaration())
3255       continue;
3256     // Summary emission does not support anonymous functions, they have to
3257     // renamed using the anonymous function renaming pass.
3258     if (!F.hasName())
3259       report_fatal_error("Unexpected anonymous function when writing summary");
3260 
3261     auto *Summary = Index->getGlobalValueSummary(F);
3262     writePerModuleFunctionSummaryRecord(
3263         NameVals, Summary,
3264         VE.getValueID(M.getValueSymbolTable().lookup(F.getName())),
3265         FSCallsAbbrev, FSCallsProfileAbbrev, F);
3266   }
3267 
3268   // Capture references from GlobalVariable initializers, which are outside
3269   // of a function scope.
3270   for (const GlobalVariable &G : M.globals())
3271     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev);
3272 
3273   for (const GlobalAlias &A : M.aliases()) {
3274     auto *Aliasee = A.getBaseObject();
3275     if (!Aliasee->hasName())
3276       // Nameless function don't have an entry in the summary, skip it.
3277       continue;
3278     auto AliasId = VE.getValueID(&A);
3279     auto AliaseeId = VE.getValueID(Aliasee);
3280     NameVals.push_back(AliasId);
3281     NameVals.push_back(getEncodedGVSummaryFlags(A));
3282     NameVals.push_back(AliaseeId);
3283     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
3284     NameVals.clear();
3285   }
3286 
3287   Stream.ExitBlock();
3288 }
3289 
3290 /// Emit the combined summary section into the combined index file.
3291 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
3292   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
3293   Stream.EmitRecord(bitc::FS_VERSION, ArrayRef<uint64_t>{INDEX_VERSION});
3294 
3295   // Abbrev for FS_COMBINED.
3296   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3297   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
3298   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3299   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3300   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3301   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3302   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3303   // numrefs x valueid, n x (valueid, callsitecount)
3304   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3305   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3306   unsigned FSCallsAbbrev = Stream.EmitAbbrev(Abbv);
3307 
3308   // Abbrev for FS_COMBINED_PROFILE.
3309   Abbv = new BitCodeAbbrev();
3310   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
3311   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3312   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3313   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3314   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3315   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3316   // numrefs x valueid, n x (valueid, callsitecount, profilecount)
3317   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3318   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3319   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(Abbv);
3320 
3321   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
3322   Abbv = new BitCodeAbbrev();
3323   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
3324   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3325   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3326   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3327   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
3328   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3329   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(Abbv);
3330 
3331   // Abbrev for FS_COMBINED_ALIAS.
3332   Abbv = new BitCodeAbbrev();
3333   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
3334   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3335   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3336   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3337   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3338   unsigned FSAliasAbbrev = Stream.EmitAbbrev(Abbv);
3339 
3340   // The aliases are emitted as a post-pass, and will point to the value
3341   // id of the aliasee. Save them in a vector for post-processing.
3342   SmallVector<AliasSummary *, 64> Aliases;
3343 
3344   // Save the value id for each summary for alias emission.
3345   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
3346 
3347   SmallVector<uint64_t, 64> NameVals;
3348 
3349   // For local linkage, we also emit the original name separately
3350   // immediately after the record.
3351   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
3352     if (!GlobalValue::isLocalLinkage(S.linkage()))
3353       return;
3354     NameVals.push_back(S.getOriginalName());
3355     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
3356     NameVals.clear();
3357   };
3358 
3359   for (const auto &I : *this) {
3360     GlobalValueSummary *S = I.second;
3361     assert(S);
3362 
3363     assert(hasValueId(I.first));
3364     unsigned ValueId = getValueId(I.first);
3365     SummaryToValueIdMap[S] = ValueId;
3366 
3367     if (auto *AS = dyn_cast<AliasSummary>(S)) {
3368       // Will process aliases as a post-pass because the reader wants all
3369       // global to be loaded first.
3370       Aliases.push_back(AS);
3371       continue;
3372     }
3373 
3374     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
3375       NameVals.push_back(ValueId);
3376       NameVals.push_back(Index.getModuleId(VS->modulePath()));
3377       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3378       for (auto &RI : VS->refs()) {
3379         NameVals.push_back(getValueId(RI.getGUID()));
3380       }
3381 
3382       // Emit the finished record.
3383       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
3384                         FSModRefsAbbrev);
3385       NameVals.clear();
3386       MaybeEmitOriginalName(*S);
3387       continue;
3388     }
3389 
3390     auto *FS = cast<FunctionSummary>(S);
3391     NameVals.push_back(ValueId);
3392     NameVals.push_back(Index.getModuleId(FS->modulePath()));
3393     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3394     NameVals.push_back(FS->instCount());
3395     NameVals.push_back(FS->refs().size());
3396 
3397     for (auto &RI : FS->refs()) {
3398       NameVals.push_back(getValueId(RI.getGUID()));
3399     }
3400 
3401     bool HasProfileData = false;
3402     for (auto &EI : FS->calls()) {
3403       HasProfileData |= EI.second.ProfileCount != 0;
3404       if (HasProfileData)
3405         break;
3406     }
3407 
3408     for (auto &EI : FS->calls()) {
3409       // If this GUID doesn't have a value id, it doesn't have a function
3410       // summary and we don't need to record any calls to it.
3411       if (!hasValueId(EI.first.getGUID()))
3412         continue;
3413       NameVals.push_back(getValueId(EI.first.getGUID()));
3414       assert(EI.second.CallsiteCount > 0 && "Expected at least one callsite");
3415       NameVals.push_back(EI.second.CallsiteCount);
3416       if (HasProfileData)
3417         NameVals.push_back(EI.second.ProfileCount);
3418     }
3419 
3420     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3421     unsigned Code =
3422         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
3423 
3424     // Emit the finished record.
3425     Stream.EmitRecord(Code, NameVals, FSAbbrev);
3426     NameVals.clear();
3427     MaybeEmitOriginalName(*S);
3428   }
3429 
3430   for (auto *AS : Aliases) {
3431     auto AliasValueId = SummaryToValueIdMap[AS];
3432     assert(AliasValueId);
3433     NameVals.push_back(AliasValueId);
3434     NameVals.push_back(Index.getModuleId(AS->modulePath()));
3435     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
3436     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
3437     assert(AliaseeValueId);
3438     NameVals.push_back(AliaseeValueId);
3439 
3440     // Emit the finished record.
3441     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
3442     NameVals.clear();
3443     MaybeEmitOriginalName(*AS);
3444   }
3445 
3446   Stream.ExitBlock();
3447 }
3448 
3449 void ModuleBitcodeWriter::writeIdentificationBlock() {
3450   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
3451 
3452   // Write the "user readable" string identifying the bitcode producer
3453   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3454   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
3455   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3456   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3457   auto StringAbbrev = Stream.EmitAbbrev(Abbv);
3458   writeStringRecord(bitc::IDENTIFICATION_CODE_STRING,
3459                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
3460 
3461   // Write the epoch version
3462   Abbv = new BitCodeAbbrev();
3463   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
3464   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3465   auto EpochAbbrev = Stream.EmitAbbrev(Abbv);
3466   SmallVector<unsigned, 1> Vals = {bitc::BITCODE_CURRENT_EPOCH};
3467   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
3468   Stream.ExitBlock();
3469 }
3470 
3471 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
3472   // Emit the module's hash.
3473   // MODULE_CODE_HASH: [5*i32]
3474   SHA1 Hasher;
3475   Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
3476                                   Buffer.size() - BlockStartPos));
3477   auto Hash = Hasher.result();
3478   SmallVector<uint64_t, 20> Vals;
3479   auto LShift = [&](unsigned char Val, unsigned Amount)
3480                     -> uint64_t { return ((uint64_t)Val) << Amount; };
3481   for (int Pos = 0; Pos < 20; Pos += 4) {
3482     uint32_t SubHash = LShift(Hash[Pos + 0], 24);
3483     SubHash |= LShift(Hash[Pos + 1], 16) | LShift(Hash[Pos + 2], 8) |
3484                (unsigned)(unsigned char)Hash[Pos + 3];
3485     Vals.push_back(SubHash);
3486   }
3487 
3488   // Emit the finished record.
3489   Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
3490 }
3491 
3492 void BitcodeWriter::write() {
3493   // Emit the file header first.
3494   writeBitcodeHeader();
3495 
3496   writeBlocks();
3497 }
3498 
3499 void ModuleBitcodeWriter::writeBlocks() {
3500   writeIdentificationBlock();
3501   writeModule();
3502 }
3503 
3504 void IndexBitcodeWriter::writeBlocks() {
3505   // Index contains only a single outer (module) block.
3506   writeIndex();
3507 }
3508 
3509 void ModuleBitcodeWriter::writeModule() {
3510   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
3511   size_t BlockStartPos = Buffer.size();
3512 
3513   SmallVector<unsigned, 1> Vals;
3514   unsigned CurVersion = 1;
3515   Vals.push_back(CurVersion);
3516   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
3517 
3518   // Emit blockinfo, which defines the standard abbreviations etc.
3519   writeBlockInfo();
3520 
3521   // Emit information about attribute groups.
3522   writeAttributeGroupTable();
3523 
3524   // Emit information about parameter attributes.
3525   writeAttributeTable();
3526 
3527   // Emit information describing all of the types in the module.
3528   writeTypeTable();
3529 
3530   writeComdats();
3531 
3532   // Emit top-level description of module, including target triple, inline asm,
3533   // descriptors for global variables, and function prototype info.
3534   writeModuleInfo();
3535 
3536   // Emit constants.
3537   writeModuleConstants();
3538 
3539   // Emit metadata.
3540   writeModuleMetadata();
3541 
3542   // Emit metadata.
3543   writeModuleMetadataStore();
3544 
3545   // Emit module-level use-lists.
3546   if (VE.shouldPreserveUseListOrder())
3547     writeUseListBlock(nullptr);
3548 
3549   writeOperandBundleTags();
3550 
3551   // Emit function bodies.
3552   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
3553   for (Module::const_iterator F = M.begin(), E = M.end(); F != E; ++F)
3554     if (!F->isDeclaration())
3555       writeFunction(*F, FunctionToBitcodeIndex);
3556 
3557   // Need to write after the above call to WriteFunction which populates
3558   // the summary information in the index.
3559   if (Index)
3560     writePerModuleGlobalValueSummary();
3561 
3562   writeValueSymbolTable(M.getValueSymbolTable(),
3563                         /* IsModuleLevel */ true, &FunctionToBitcodeIndex);
3564 
3565   if (GenerateHash) {
3566     writeModuleHash(BlockStartPos);
3567   }
3568 
3569   Stream.ExitBlock();
3570 }
3571 
3572 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
3573                                uint32_t &Position) {
3574   support::endian::write32le(&Buffer[Position], Value);
3575   Position += 4;
3576 }
3577 
3578 /// If generating a bc file on darwin, we have to emit a
3579 /// header and trailer to make it compatible with the system archiver.  To do
3580 /// this we emit the following header, and then emit a trailer that pads the
3581 /// file out to be a multiple of 16 bytes.
3582 ///
3583 /// struct bc_header {
3584 ///   uint32_t Magic;         // 0x0B17C0DE
3585 ///   uint32_t Version;       // Version, currently always 0.
3586 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
3587 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
3588 ///   uint32_t CPUType;       // CPU specifier.
3589 ///   ... potentially more later ...
3590 /// };
3591 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
3592                                          const Triple &TT) {
3593   unsigned CPUType = ~0U;
3594 
3595   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
3596   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
3597   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
3598   // specific constants here because they are implicitly part of the Darwin ABI.
3599   enum {
3600     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
3601     DARWIN_CPU_TYPE_X86        = 7,
3602     DARWIN_CPU_TYPE_ARM        = 12,
3603     DARWIN_CPU_TYPE_POWERPC    = 18
3604   };
3605 
3606   Triple::ArchType Arch = TT.getArch();
3607   if (Arch == Triple::x86_64)
3608     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
3609   else if (Arch == Triple::x86)
3610     CPUType = DARWIN_CPU_TYPE_X86;
3611   else if (Arch == Triple::ppc)
3612     CPUType = DARWIN_CPU_TYPE_POWERPC;
3613   else if (Arch == Triple::ppc64)
3614     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
3615   else if (Arch == Triple::arm || Arch == Triple::thumb)
3616     CPUType = DARWIN_CPU_TYPE_ARM;
3617 
3618   // Traditional Bitcode starts after header.
3619   assert(Buffer.size() >= BWH_HeaderSize &&
3620          "Expected header size to be reserved");
3621   unsigned BCOffset = BWH_HeaderSize;
3622   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
3623 
3624   // Write the magic and version.
3625   unsigned Position = 0;
3626   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
3627   writeInt32ToBuffer(0, Buffer, Position); // Version.
3628   writeInt32ToBuffer(BCOffset, Buffer, Position);
3629   writeInt32ToBuffer(BCSize, Buffer, Position);
3630   writeInt32ToBuffer(CPUType, Buffer, Position);
3631 
3632   // If the file is not a multiple of 16 bytes, insert dummy padding.
3633   while (Buffer.size() & 15)
3634     Buffer.push_back(0);
3635 }
3636 
3637 /// Helper to write the header common to all bitcode files.
3638 void BitcodeWriter::writeBitcodeHeader() {
3639   // Emit the file header.
3640   Stream.Emit((unsigned)'B', 8);
3641   Stream.Emit((unsigned)'C', 8);
3642   Stream.Emit(0x0, 4);
3643   Stream.Emit(0xC, 4);
3644   Stream.Emit(0xE, 4);
3645   Stream.Emit(0xD, 4);
3646 }
3647 
3648 /// WriteBitcodeToFile - Write the specified module to the specified output
3649 /// stream.
3650 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out,
3651                               bool ShouldPreserveUseListOrder,
3652                               const ModuleSummaryIndex *Index,
3653                               bool GenerateHash) {
3654   SmallVector<char, 0> Buffer;
3655   Buffer.reserve(256*1024);
3656 
3657   // If this is darwin or another generic macho target, reserve space for the
3658   // header.
3659   Triple TT(M->getTargetTriple());
3660   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
3661     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
3662 
3663   // Emit the module into the buffer.
3664   ModuleBitcodeWriter ModuleWriter(M, Buffer, ShouldPreserveUseListOrder, Index,
3665                                    GenerateHash);
3666   ModuleWriter.write();
3667 
3668   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
3669     emitDarwinBCHeaderAndTrailer(Buffer, TT);
3670 
3671   // Write the generated bitstream to "Out".
3672   Out.write((char*)&Buffer.front(), Buffer.size());
3673 }
3674 
3675 void IndexBitcodeWriter::writeIndex() {
3676   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
3677 
3678   SmallVector<unsigned, 1> Vals;
3679   unsigned CurVersion = 1;
3680   Vals.push_back(CurVersion);
3681   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
3682 
3683   // If we have a VST, write the VSTOFFSET record placeholder.
3684   writeValueSymbolTableForwardDecl();
3685 
3686   // Write the module paths in the combined index.
3687   writeModStrings();
3688 
3689   // Write the summary combined index records.
3690   writeCombinedGlobalValueSummary();
3691 
3692   // Need a special VST writer for the combined index (we don't have a
3693   // real VST and real values when this is invoked).
3694   writeCombinedValueSymbolTable();
3695 
3696   Stream.ExitBlock();
3697 }
3698 
3699 // Write the specified module summary index to the given raw output stream,
3700 // where it will be written in a new bitcode block. This is used when
3701 // writing the combined index file for ThinLTO. When writing a subset of the
3702 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
3703 void llvm::WriteIndexToFile(
3704     const ModuleSummaryIndex &Index, raw_ostream &Out,
3705     std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
3706   SmallVector<char, 0> Buffer;
3707   Buffer.reserve(256 * 1024);
3708 
3709   IndexBitcodeWriter IndexWriter(Buffer, Index, ModuleToSummariesForIndex);
3710   IndexWriter.write();
3711 
3712   Out.write((char *)&Buffer.front(), Buffer.size());
3713 }
3714