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