xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision a59d3e5af889662139b8b08f2175f12567491441)
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                                            GlobalValueInfo *Info,
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 public:
274   /// Constructs a IndexBitcodeWriter object for the given combined index,
275   /// writing to the provided \p Buffer.
276   IndexBitcodeWriter(SmallVectorImpl<char> &Buffer,
277                      const ModuleSummaryIndex &Index)
278       : BitcodeWriter(Buffer), Index(Index) {
279     // Assign unique value ids to all functions in the index for use
280     // in writing out the call graph edges. Save the mapping from GUID
281     // to the new global value id to use when writing those edges, which
282     // are currently saved in the index in terms of GUID.
283     for (auto &II : Index)
284       GUIDToValueIdMap[II.first] = ++GlobalValueId;
285   }
286 
287 private:
288   /// Main entry point for writing a combined index to bitcode, invoked by
289   /// BitcodeWriter::write() after it writes the header.
290   void writeBlocks() override;
291 
292   void writeIndex();
293   void writeModStrings();
294   void writeCombinedValueSymbolTable();
295   void writeCombinedGlobalValueSummary();
296 
297   bool hasValueId(GlobalValue::GUID ValGUID) {
298     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
299     return VMI != GUIDToValueIdMap.end();
300   }
301   unsigned getValueId(GlobalValue::GUID ValGUID) {
302     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
303     // If this GUID doesn't have an entry, assign one.
304     if (VMI == GUIDToValueIdMap.end()) {
305       GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
306       return GlobalValueId;
307     } else {
308       return VMI->second;
309     }
310   }
311   unsigned popValueId(GlobalValue::GUID ValGUID) {
312     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
313     assert(VMI != GUIDToValueIdMap.end());
314     unsigned ValueId = VMI->second;
315     GUIDToValueIdMap.erase(VMI);
316     return ValueId;
317   }
318   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
319 };
320 
321 static unsigned getEncodedCastOpcode(unsigned Opcode) {
322   switch (Opcode) {
323   default: llvm_unreachable("Unknown cast instruction!");
324   case Instruction::Trunc   : return bitc::CAST_TRUNC;
325   case Instruction::ZExt    : return bitc::CAST_ZEXT;
326   case Instruction::SExt    : return bitc::CAST_SEXT;
327   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
328   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
329   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
330   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
331   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
332   case Instruction::FPExt   : return bitc::CAST_FPEXT;
333   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
334   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
335   case Instruction::BitCast : return bitc::CAST_BITCAST;
336   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
337   }
338 }
339 
340 static unsigned getEncodedBinaryOpcode(unsigned Opcode) {
341   switch (Opcode) {
342   default: llvm_unreachable("Unknown binary instruction!");
343   case Instruction::Add:
344   case Instruction::FAdd: return bitc::BINOP_ADD;
345   case Instruction::Sub:
346   case Instruction::FSub: return bitc::BINOP_SUB;
347   case Instruction::Mul:
348   case Instruction::FMul: return bitc::BINOP_MUL;
349   case Instruction::UDiv: return bitc::BINOP_UDIV;
350   case Instruction::FDiv:
351   case Instruction::SDiv: return bitc::BINOP_SDIV;
352   case Instruction::URem: return bitc::BINOP_UREM;
353   case Instruction::FRem:
354   case Instruction::SRem: return bitc::BINOP_SREM;
355   case Instruction::Shl:  return bitc::BINOP_SHL;
356   case Instruction::LShr: return bitc::BINOP_LSHR;
357   case Instruction::AShr: return bitc::BINOP_ASHR;
358   case Instruction::And:  return bitc::BINOP_AND;
359   case Instruction::Or:   return bitc::BINOP_OR;
360   case Instruction::Xor:  return bitc::BINOP_XOR;
361   }
362 }
363 
364 static unsigned getEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
365   switch (Op) {
366   default: llvm_unreachable("Unknown RMW operation!");
367   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
368   case AtomicRMWInst::Add: return bitc::RMW_ADD;
369   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
370   case AtomicRMWInst::And: return bitc::RMW_AND;
371   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
372   case AtomicRMWInst::Or: return bitc::RMW_OR;
373   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
374   case AtomicRMWInst::Max: return bitc::RMW_MAX;
375   case AtomicRMWInst::Min: return bitc::RMW_MIN;
376   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
377   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
378   }
379 }
380 
381 static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
382   switch (Ordering) {
383   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
384   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
385   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
386   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
387   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
388   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
389   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
390   }
391   llvm_unreachable("Invalid ordering");
392 }
393 
394 static unsigned getEncodedSynchScope(SynchronizationScope SynchScope) {
395   switch (SynchScope) {
396   case SingleThread: return bitc::SYNCHSCOPE_SINGLETHREAD;
397   case CrossThread: return bitc::SYNCHSCOPE_CROSSTHREAD;
398   }
399   llvm_unreachable("Invalid synch scope");
400 }
401 
402 void ModuleBitcodeWriter::writeStringRecord(unsigned Code, StringRef Str,
403                                             unsigned AbbrevToUse) {
404   SmallVector<unsigned, 64> Vals;
405 
406   // Code: [strchar x N]
407   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
408     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
409       AbbrevToUse = 0;
410     Vals.push_back(Str[i]);
411   }
412 
413   // Emit the finished record.
414   Stream.EmitRecord(Code, Vals, AbbrevToUse);
415 }
416 
417 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
418   switch (Kind) {
419   case Attribute::Alignment:
420     return bitc::ATTR_KIND_ALIGNMENT;
421   case Attribute::AllocSize:
422     return bitc::ATTR_KIND_ALLOC_SIZE;
423   case Attribute::AlwaysInline:
424     return bitc::ATTR_KIND_ALWAYS_INLINE;
425   case Attribute::ArgMemOnly:
426     return bitc::ATTR_KIND_ARGMEMONLY;
427   case Attribute::Builtin:
428     return bitc::ATTR_KIND_BUILTIN;
429   case Attribute::ByVal:
430     return bitc::ATTR_KIND_BY_VAL;
431   case Attribute::Convergent:
432     return bitc::ATTR_KIND_CONVERGENT;
433   case Attribute::InAlloca:
434     return bitc::ATTR_KIND_IN_ALLOCA;
435   case Attribute::Cold:
436     return bitc::ATTR_KIND_COLD;
437   case Attribute::InaccessibleMemOnly:
438     return bitc::ATTR_KIND_INACCESSIBLEMEM_ONLY;
439   case Attribute::InaccessibleMemOrArgMemOnly:
440     return bitc::ATTR_KIND_INACCESSIBLEMEM_OR_ARGMEMONLY;
441   case Attribute::InlineHint:
442     return bitc::ATTR_KIND_INLINE_HINT;
443   case Attribute::InReg:
444     return bitc::ATTR_KIND_IN_REG;
445   case Attribute::JumpTable:
446     return bitc::ATTR_KIND_JUMP_TABLE;
447   case Attribute::MinSize:
448     return bitc::ATTR_KIND_MIN_SIZE;
449   case Attribute::Naked:
450     return bitc::ATTR_KIND_NAKED;
451   case Attribute::Nest:
452     return bitc::ATTR_KIND_NEST;
453   case Attribute::NoAlias:
454     return bitc::ATTR_KIND_NO_ALIAS;
455   case Attribute::NoBuiltin:
456     return bitc::ATTR_KIND_NO_BUILTIN;
457   case Attribute::NoCapture:
458     return bitc::ATTR_KIND_NO_CAPTURE;
459   case Attribute::NoDuplicate:
460     return bitc::ATTR_KIND_NO_DUPLICATE;
461   case Attribute::NoImplicitFloat:
462     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
463   case Attribute::NoInline:
464     return bitc::ATTR_KIND_NO_INLINE;
465   case Attribute::NoRecurse:
466     return bitc::ATTR_KIND_NO_RECURSE;
467   case Attribute::NonLazyBind:
468     return bitc::ATTR_KIND_NON_LAZY_BIND;
469   case Attribute::NonNull:
470     return bitc::ATTR_KIND_NON_NULL;
471   case Attribute::Dereferenceable:
472     return bitc::ATTR_KIND_DEREFERENCEABLE;
473   case Attribute::DereferenceableOrNull:
474     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
475   case Attribute::NoRedZone:
476     return bitc::ATTR_KIND_NO_RED_ZONE;
477   case Attribute::NoReturn:
478     return bitc::ATTR_KIND_NO_RETURN;
479   case Attribute::NoUnwind:
480     return bitc::ATTR_KIND_NO_UNWIND;
481   case Attribute::OptimizeForSize:
482     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
483   case Attribute::OptimizeNone:
484     return bitc::ATTR_KIND_OPTIMIZE_NONE;
485   case Attribute::ReadNone:
486     return bitc::ATTR_KIND_READ_NONE;
487   case Attribute::ReadOnly:
488     return bitc::ATTR_KIND_READ_ONLY;
489   case Attribute::Returned:
490     return bitc::ATTR_KIND_RETURNED;
491   case Attribute::ReturnsTwice:
492     return bitc::ATTR_KIND_RETURNS_TWICE;
493   case Attribute::SExt:
494     return bitc::ATTR_KIND_S_EXT;
495   case Attribute::StackAlignment:
496     return bitc::ATTR_KIND_STACK_ALIGNMENT;
497   case Attribute::StackProtect:
498     return bitc::ATTR_KIND_STACK_PROTECT;
499   case Attribute::StackProtectReq:
500     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
501   case Attribute::StackProtectStrong:
502     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
503   case Attribute::SafeStack:
504     return bitc::ATTR_KIND_SAFESTACK;
505   case Attribute::StructRet:
506     return bitc::ATTR_KIND_STRUCT_RET;
507   case Attribute::SanitizeAddress:
508     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
509   case Attribute::SanitizeThread:
510     return bitc::ATTR_KIND_SANITIZE_THREAD;
511   case Attribute::SanitizeMemory:
512     return bitc::ATTR_KIND_SANITIZE_MEMORY;
513   case Attribute::SwiftError:
514     return bitc::ATTR_KIND_SWIFT_ERROR;
515   case Attribute::SwiftSelf:
516     return bitc::ATTR_KIND_SWIFT_SELF;
517   case Attribute::UWTable:
518     return bitc::ATTR_KIND_UW_TABLE;
519   case Attribute::ZExt:
520     return bitc::ATTR_KIND_Z_EXT;
521   case Attribute::EndAttrKinds:
522     llvm_unreachable("Can not encode end-attribute kinds marker.");
523   case Attribute::None:
524     llvm_unreachable("Can not encode none-attribute.");
525   }
526 
527   llvm_unreachable("Trying to encode unknown attribute");
528 }
529 
530 void ModuleBitcodeWriter::writeAttributeGroupTable() {
531   const std::vector<AttributeSet> &AttrGrps = VE.getAttributeGroups();
532   if (AttrGrps.empty()) return;
533 
534   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
535 
536   SmallVector<uint64_t, 64> Record;
537   for (unsigned i = 0, e = AttrGrps.size(); i != e; ++i) {
538     AttributeSet AS = AttrGrps[i];
539     for (unsigned i = 0, e = AS.getNumSlots(); i != e; ++i) {
540       AttributeSet A = AS.getSlotAttributes(i);
541 
542       Record.push_back(VE.getAttributeGroupID(A));
543       Record.push_back(AS.getSlotIndex(i));
544 
545       for (AttributeSet::iterator I = AS.begin(0), E = AS.end(0);
546            I != E; ++I) {
547         Attribute Attr = *I;
548         if (Attr.isEnumAttribute()) {
549           Record.push_back(0);
550           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
551         } else if (Attr.isIntAttribute()) {
552           Record.push_back(1);
553           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
554           Record.push_back(Attr.getValueAsInt());
555         } else {
556           StringRef Kind = Attr.getKindAsString();
557           StringRef Val = Attr.getValueAsString();
558 
559           Record.push_back(Val.empty() ? 3 : 4);
560           Record.append(Kind.begin(), Kind.end());
561           Record.push_back(0);
562           if (!Val.empty()) {
563             Record.append(Val.begin(), Val.end());
564             Record.push_back(0);
565           }
566         }
567       }
568 
569       Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
570       Record.clear();
571     }
572   }
573 
574   Stream.ExitBlock();
575 }
576 
577 void ModuleBitcodeWriter::writeAttributeTable() {
578   const std::vector<AttributeSet> &Attrs = VE.getAttributes();
579   if (Attrs.empty()) return;
580 
581   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
582 
583   SmallVector<uint64_t, 64> Record;
584   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
585     const AttributeSet &A = Attrs[i];
586     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i)
587       Record.push_back(VE.getAttributeGroupID(A.getSlotAttributes(i)));
588 
589     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
590     Record.clear();
591   }
592 
593   Stream.ExitBlock();
594 }
595 
596 /// WriteTypeTable - Write out the type table for a module.
597 void ModuleBitcodeWriter::writeTypeTable() {
598   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
599 
600   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
601   SmallVector<uint64_t, 64> TypeVals;
602 
603   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
604 
605   // Abbrev for TYPE_CODE_POINTER.
606   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
607   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
608   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
609   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
610   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
611 
612   // Abbrev for TYPE_CODE_FUNCTION.
613   Abbv = new BitCodeAbbrev();
614   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
615   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
616   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
617   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
618 
619   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
620 
621   // Abbrev for TYPE_CODE_STRUCT_ANON.
622   Abbv = new BitCodeAbbrev();
623   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
624   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
625   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
626   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
627 
628   unsigned StructAnonAbbrev = Stream.EmitAbbrev(Abbv);
629 
630   // Abbrev for TYPE_CODE_STRUCT_NAME.
631   Abbv = new BitCodeAbbrev();
632   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
633   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
634   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
635   unsigned StructNameAbbrev = Stream.EmitAbbrev(Abbv);
636 
637   // Abbrev for TYPE_CODE_STRUCT_NAMED.
638   Abbv = new BitCodeAbbrev();
639   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
640   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
641   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
642   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
643 
644   unsigned StructNamedAbbrev = Stream.EmitAbbrev(Abbv);
645 
646   // Abbrev for TYPE_CODE_ARRAY.
647   Abbv = new BitCodeAbbrev();
648   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
649   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
650   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
651 
652   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
653 
654   // Emit an entry count so the reader can reserve space.
655   TypeVals.push_back(TypeList.size());
656   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
657   TypeVals.clear();
658 
659   // Loop over all of the types, emitting each in turn.
660   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
661     Type *T = TypeList[i];
662     int AbbrevToUse = 0;
663     unsigned Code = 0;
664 
665     switch (T->getTypeID()) {
666     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
667     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
668     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
669     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
670     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
671     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
672     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
673     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
674     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
675     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
676     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
677     case Type::IntegerTyID:
678       // INTEGER: [width]
679       Code = bitc::TYPE_CODE_INTEGER;
680       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
681       break;
682     case Type::PointerTyID: {
683       PointerType *PTy = cast<PointerType>(T);
684       // POINTER: [pointee type, address space]
685       Code = bitc::TYPE_CODE_POINTER;
686       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
687       unsigned AddressSpace = PTy->getAddressSpace();
688       TypeVals.push_back(AddressSpace);
689       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
690       break;
691     }
692     case Type::FunctionTyID: {
693       FunctionType *FT = cast<FunctionType>(T);
694       // FUNCTION: [isvararg, retty, paramty x N]
695       Code = bitc::TYPE_CODE_FUNCTION;
696       TypeVals.push_back(FT->isVarArg());
697       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
698       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
699         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
700       AbbrevToUse = FunctionAbbrev;
701       break;
702     }
703     case Type::StructTyID: {
704       StructType *ST = cast<StructType>(T);
705       // STRUCT: [ispacked, eltty x N]
706       TypeVals.push_back(ST->isPacked());
707       // Output all of the element types.
708       for (StructType::element_iterator I = ST->element_begin(),
709            E = ST->element_end(); I != E; ++I)
710         TypeVals.push_back(VE.getTypeID(*I));
711 
712       if (ST->isLiteral()) {
713         Code = bitc::TYPE_CODE_STRUCT_ANON;
714         AbbrevToUse = StructAnonAbbrev;
715       } else {
716         if (ST->isOpaque()) {
717           Code = bitc::TYPE_CODE_OPAQUE;
718         } else {
719           Code = bitc::TYPE_CODE_STRUCT_NAMED;
720           AbbrevToUse = StructNamedAbbrev;
721         }
722 
723         // Emit the name if it is present.
724         if (!ST->getName().empty())
725           writeStringRecord(bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
726                             StructNameAbbrev);
727       }
728       break;
729     }
730     case Type::ArrayTyID: {
731       ArrayType *AT = cast<ArrayType>(T);
732       // ARRAY: [numelts, eltty]
733       Code = bitc::TYPE_CODE_ARRAY;
734       TypeVals.push_back(AT->getNumElements());
735       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
736       AbbrevToUse = ArrayAbbrev;
737       break;
738     }
739     case Type::VectorTyID: {
740       VectorType *VT = cast<VectorType>(T);
741       // VECTOR [numelts, eltty]
742       Code = bitc::TYPE_CODE_VECTOR;
743       TypeVals.push_back(VT->getNumElements());
744       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
745       break;
746     }
747     }
748 
749     // Emit the finished record.
750     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
751     TypeVals.clear();
752   }
753 
754   Stream.ExitBlock();
755 }
756 
757 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
758   switch (Linkage) {
759   case GlobalValue::ExternalLinkage:
760     return 0;
761   case GlobalValue::WeakAnyLinkage:
762     return 16;
763   case GlobalValue::AppendingLinkage:
764     return 2;
765   case GlobalValue::InternalLinkage:
766     return 3;
767   case GlobalValue::LinkOnceAnyLinkage:
768     return 18;
769   case GlobalValue::ExternalWeakLinkage:
770     return 7;
771   case GlobalValue::CommonLinkage:
772     return 8;
773   case GlobalValue::PrivateLinkage:
774     return 9;
775   case GlobalValue::WeakODRLinkage:
776     return 17;
777   case GlobalValue::LinkOnceODRLinkage:
778     return 19;
779   case GlobalValue::AvailableExternallyLinkage:
780     return 12;
781   }
782   llvm_unreachable("Invalid linkage");
783 }
784 
785 static unsigned getEncodedLinkage(const GlobalValue &GV) {
786   return getEncodedLinkage(GV.getLinkage());
787 }
788 
789 static unsigned getEncodedVisibility(const GlobalValue &GV) {
790   switch (GV.getVisibility()) {
791   case GlobalValue::DefaultVisibility:   return 0;
792   case GlobalValue::HiddenVisibility:    return 1;
793   case GlobalValue::ProtectedVisibility: return 2;
794   }
795   llvm_unreachable("Invalid visibility");
796 }
797 
798 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
799   switch (GV.getDLLStorageClass()) {
800   case GlobalValue::DefaultStorageClass:   return 0;
801   case GlobalValue::DLLImportStorageClass: return 1;
802   case GlobalValue::DLLExportStorageClass: return 2;
803   }
804   llvm_unreachable("Invalid DLL storage class");
805 }
806 
807 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
808   switch (GV.getThreadLocalMode()) {
809     case GlobalVariable::NotThreadLocal:         return 0;
810     case GlobalVariable::GeneralDynamicTLSModel: return 1;
811     case GlobalVariable::LocalDynamicTLSModel:   return 2;
812     case GlobalVariable::InitialExecTLSModel:    return 3;
813     case GlobalVariable::LocalExecTLSModel:      return 4;
814   }
815   llvm_unreachable("Invalid TLS model");
816 }
817 
818 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
819   switch (C.getSelectionKind()) {
820   case Comdat::Any:
821     return bitc::COMDAT_SELECTION_KIND_ANY;
822   case Comdat::ExactMatch:
823     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
824   case Comdat::Largest:
825     return bitc::COMDAT_SELECTION_KIND_LARGEST;
826   case Comdat::NoDuplicates:
827     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
828   case Comdat::SameSize:
829     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
830   }
831   llvm_unreachable("Invalid selection kind");
832 }
833 
834 void ModuleBitcodeWriter::writeComdats() {
835   SmallVector<unsigned, 64> Vals;
836   for (const Comdat *C : VE.getComdats()) {
837     // COMDAT: [selection_kind, name]
838     Vals.push_back(getEncodedComdatSelectionKind(*C));
839     size_t Size = C->getName().size();
840     assert(isUInt<32>(Size));
841     Vals.push_back(Size);
842     for (char Chr : C->getName())
843       Vals.push_back((unsigned char)Chr);
844     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
845     Vals.clear();
846   }
847 }
848 
849 /// Write a record that will eventually hold the word offset of the
850 /// module-level VST. For now the offset is 0, which will be backpatched
851 /// after the real VST is written. Saves the bit offset to backpatch.
852 void BitcodeWriter::writeValueSymbolTableForwardDecl() {
853   // Write a placeholder value in for the offset of the real VST,
854   // which is written after the function blocks so that it can include
855   // the offset of each function. The placeholder offset will be
856   // updated when the real VST is written.
857   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
858   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
859   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
860   // hold the real VST offset. Must use fixed instead of VBR as we don't
861   // know how many VBR chunks to reserve ahead of time.
862   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
863   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(Abbv);
864 
865   // Emit the placeholder
866   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
867   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
868 
869   // Compute and save the bit offset to the placeholder, which will be
870   // patched when the real VST is written. We can simply subtract the 32-bit
871   // fixed size from the current bit number to get the location to backpatch.
872   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
873 }
874 
875 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
876 
877 /// Determine the encoding to use for the given string name and length.
878 static StringEncoding getStringEncoding(const char *Str, unsigned StrLen) {
879   bool isChar6 = true;
880   for (const char *C = Str, *E = C + StrLen; C != E; ++C) {
881     if (isChar6)
882       isChar6 = BitCodeAbbrevOp::isChar6(*C);
883     if ((unsigned char)*C & 128)
884       // don't bother scanning the rest.
885       return SE_Fixed8;
886   }
887   if (isChar6)
888     return SE_Char6;
889   else
890     return SE_Fixed7;
891 }
892 
893 /// Emit top-level description of module, including target triple, inline asm,
894 /// descriptors for global variables, and function prototype info.
895 /// Returns the bit offset to backpatch with the location of the real VST.
896 void ModuleBitcodeWriter::writeModuleInfo() {
897   // Emit various pieces of data attached to a module.
898   if (!M.getTargetTriple().empty())
899     writeStringRecord(bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
900                       0 /*TODO*/);
901   const std::string &DL = M.getDataLayoutStr();
902   if (!DL.empty())
903     writeStringRecord(bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
904   if (!M.getModuleInlineAsm().empty())
905     writeStringRecord(bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
906                       0 /*TODO*/);
907 
908   // Emit information about sections and GC, computing how many there are. Also
909   // compute the maximum alignment value.
910   std::map<std::string, unsigned> SectionMap;
911   std::map<std::string, unsigned> GCMap;
912   unsigned MaxAlignment = 0;
913   unsigned MaxGlobalType = 0;
914   for (const GlobalValue &GV : M.globals()) {
915     MaxAlignment = std::max(MaxAlignment, GV.getAlignment());
916     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
917     if (GV.hasSection()) {
918       // Give section names unique ID's.
919       unsigned &Entry = SectionMap[GV.getSection()];
920       if (!Entry) {
921         writeStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
922                           0 /*TODO*/);
923         Entry = SectionMap.size();
924       }
925     }
926   }
927   for (const Function &F : M) {
928     MaxAlignment = std::max(MaxAlignment, F.getAlignment());
929     if (F.hasSection()) {
930       // Give section names unique ID's.
931       unsigned &Entry = SectionMap[F.getSection()];
932       if (!Entry) {
933         writeStringRecord(bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
934                           0 /*TODO*/);
935         Entry = SectionMap.size();
936       }
937     }
938     if (F.hasGC()) {
939       // Same for GC names.
940       unsigned &Entry = GCMap[F.getGC()];
941       if (!Entry) {
942         writeStringRecord(bitc::MODULE_CODE_GCNAME, F.getGC(), 0 /*TODO*/);
943         Entry = GCMap.size();
944       }
945     }
946   }
947 
948   // Emit abbrev for globals, now that we know # sections and max alignment.
949   unsigned SimpleGVarAbbrev = 0;
950   if (!M.global_empty()) {
951     // Add an abbrev for common globals with no visibility or thread localness.
952     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
953     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
954     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
955                               Log2_32_Ceil(MaxGlobalType+1)));
956     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
957                                                            //| explicitType << 1
958                                                            //| constant
959     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
960     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
961     if (MaxAlignment == 0)                                 // Alignment.
962       Abbv->Add(BitCodeAbbrevOp(0));
963     else {
964       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
965       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
966                                Log2_32_Ceil(MaxEncAlignment+1)));
967     }
968     if (SectionMap.empty())                                    // Section.
969       Abbv->Add(BitCodeAbbrevOp(0));
970     else
971       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
972                                Log2_32_Ceil(SectionMap.size()+1)));
973     // Don't bother emitting vis + thread local.
974     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
975   }
976 
977   // Emit the global variable information.
978   SmallVector<unsigned, 64> Vals;
979   for (const GlobalVariable &GV : M.globals()) {
980     unsigned AbbrevToUse = 0;
981 
982     // GLOBALVAR: [type, isconst, initid,
983     //             linkage, alignment, section, visibility, threadlocal,
984     //             unnamed_addr, externally_initialized, dllstorageclass,
985     //             comdat]
986     Vals.push_back(VE.getTypeID(GV.getValueType()));
987     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
988     Vals.push_back(GV.isDeclaration() ? 0 :
989                    (VE.getValueID(GV.getInitializer()) + 1));
990     Vals.push_back(getEncodedLinkage(GV));
991     Vals.push_back(Log2_32(GV.getAlignment())+1);
992     Vals.push_back(GV.hasSection() ? SectionMap[GV.getSection()] : 0);
993     if (GV.isThreadLocal() ||
994         GV.getVisibility() != GlobalValue::DefaultVisibility ||
995         GV.hasUnnamedAddr() || GV.isExternallyInitialized() ||
996         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
997         GV.hasComdat()) {
998       Vals.push_back(getEncodedVisibility(GV));
999       Vals.push_back(getEncodedThreadLocalMode(GV));
1000       Vals.push_back(GV.hasUnnamedAddr());
1001       Vals.push_back(GV.isExternallyInitialized());
1002       Vals.push_back(getEncodedDLLStorageClass(GV));
1003       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1004     } else {
1005       AbbrevToUse = SimpleGVarAbbrev;
1006     }
1007 
1008     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1009     Vals.clear();
1010   }
1011 
1012   // Emit the function proto information.
1013   for (const Function &F : M) {
1014     // FUNCTION:  [type, callingconv, isproto, linkage, paramattrs, alignment,
1015     //             section, visibility, gc, unnamed_addr, prologuedata,
1016     //             dllstorageclass, comdat, prefixdata, personalityfn]
1017     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1018     Vals.push_back(F.getCallingConv());
1019     Vals.push_back(F.isDeclaration());
1020     Vals.push_back(getEncodedLinkage(F));
1021     Vals.push_back(VE.getAttributeID(F.getAttributes()));
1022     Vals.push_back(Log2_32(F.getAlignment())+1);
1023     Vals.push_back(F.hasSection() ? SectionMap[F.getSection()] : 0);
1024     Vals.push_back(getEncodedVisibility(F));
1025     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1026     Vals.push_back(F.hasUnnamedAddr());
1027     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1028                                        : 0);
1029     Vals.push_back(getEncodedDLLStorageClass(F));
1030     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1031     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1032                                      : 0);
1033     Vals.push_back(
1034         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1035 
1036     unsigned AbbrevToUse = 0;
1037     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1038     Vals.clear();
1039   }
1040 
1041   // Emit the alias information.
1042   for (const GlobalAlias &A : M.aliases()) {
1043     // ALIAS: [alias type, aliasee val#, linkage, visibility]
1044     Vals.push_back(VE.getTypeID(A.getValueType()));
1045     Vals.push_back(A.getType()->getAddressSpace());
1046     Vals.push_back(VE.getValueID(A.getAliasee()));
1047     Vals.push_back(getEncodedLinkage(A));
1048     Vals.push_back(getEncodedVisibility(A));
1049     Vals.push_back(getEncodedDLLStorageClass(A));
1050     Vals.push_back(getEncodedThreadLocalMode(A));
1051     Vals.push_back(A.hasUnnamedAddr());
1052     unsigned AbbrevToUse = 0;
1053     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1054     Vals.clear();
1055   }
1056 
1057   // Emit the ifunc information.
1058   for (const GlobalIFunc &I : M.ifuncs()) {
1059     // IFUNC: [ifunc type, address space, resolver val#, linkage, visibility]
1060     Vals.push_back(VE.getTypeID(I.getValueType()));
1061     Vals.push_back(I.getType()->getAddressSpace());
1062     Vals.push_back(VE.getValueID(I.getResolver()));
1063     Vals.push_back(getEncodedLinkage(I));
1064     Vals.push_back(getEncodedVisibility(I));
1065     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1066     Vals.clear();
1067   }
1068 
1069   // Emit the module's source file name.
1070   {
1071     StringEncoding Bits = getStringEncoding(M.getSourceFileName().data(),
1072                                             M.getSourceFileName().size());
1073     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1074     if (Bits == SE_Char6)
1075       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1076     else if (Bits == SE_Fixed7)
1077       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1078 
1079     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1080     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1081     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1082     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1083     Abbv->Add(AbbrevOpToUse);
1084     unsigned FilenameAbbrev = Stream.EmitAbbrev(Abbv);
1085 
1086     for (const auto P : M.getSourceFileName())
1087       Vals.push_back((unsigned char)P);
1088 
1089     // Emit the finished record.
1090     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1091     Vals.clear();
1092   }
1093 
1094   // If we have a VST, write the VSTOFFSET record placeholder.
1095   if (M.getValueSymbolTable().empty())
1096     return;
1097   writeValueSymbolTableForwardDecl();
1098 }
1099 
1100 static uint64_t getOptimizationFlags(const Value *V) {
1101   uint64_t Flags = 0;
1102 
1103   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1104     if (OBO->hasNoSignedWrap())
1105       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1106     if (OBO->hasNoUnsignedWrap())
1107       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1108   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1109     if (PEO->isExact())
1110       Flags |= 1 << bitc::PEO_EXACT;
1111   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1112     if (FPMO->hasUnsafeAlgebra())
1113       Flags |= FastMathFlags::UnsafeAlgebra;
1114     if (FPMO->hasNoNaNs())
1115       Flags |= FastMathFlags::NoNaNs;
1116     if (FPMO->hasNoInfs())
1117       Flags |= FastMathFlags::NoInfs;
1118     if (FPMO->hasNoSignedZeros())
1119       Flags |= FastMathFlags::NoSignedZeros;
1120     if (FPMO->hasAllowReciprocal())
1121       Flags |= FastMathFlags::AllowReciprocal;
1122   }
1123 
1124   return Flags;
1125 }
1126 
1127 void ModuleBitcodeWriter::writeValueAsMetadata(
1128     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1129   // Mimic an MDNode with a value as one operand.
1130   Value *V = MD->getValue();
1131   Record.push_back(VE.getTypeID(V->getType()));
1132   Record.push_back(VE.getValueID(V));
1133   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1134   Record.clear();
1135 }
1136 
1137 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1138                                        SmallVectorImpl<uint64_t> &Record,
1139                                        unsigned Abbrev) {
1140   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1141     Metadata *MD = N->getOperand(i);
1142     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1143            "Unexpected function-local metadata");
1144     Record.push_back(VE.getMetadataOrNullID(MD));
1145   }
1146   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1147                                     : bitc::METADATA_NODE,
1148                     Record, Abbrev);
1149   Record.clear();
1150 }
1151 
1152 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1153   // Assume the column is usually under 128, and always output the inlined-at
1154   // location (it's never more expensive than building an array size 1).
1155   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1156   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1157   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1158   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1159   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1160   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1161   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1162   return Stream.EmitAbbrev(Abbv);
1163 }
1164 
1165 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1166                                           SmallVectorImpl<uint64_t> &Record,
1167                                           unsigned &Abbrev) {
1168   if (!Abbrev)
1169     Abbrev = createDILocationAbbrev();
1170 
1171   Record.push_back(N->isDistinct());
1172   Record.push_back(N->getLine());
1173   Record.push_back(N->getColumn());
1174   Record.push_back(VE.getMetadataID(N->getScope()));
1175   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1176 
1177   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1178   Record.clear();
1179 }
1180 
1181 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1182   // Assume the column is usually under 128, and always output the inlined-at
1183   // location (it's never more expensive than building an array size 1).
1184   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1185   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1186   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1187   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1188   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1189   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1190   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1191   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1192   return Stream.EmitAbbrev(Abbv);
1193 }
1194 
1195 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1196                                              SmallVectorImpl<uint64_t> &Record,
1197                                              unsigned &Abbrev) {
1198   if (!Abbrev)
1199     Abbrev = createGenericDINodeAbbrev();
1200 
1201   Record.push_back(N->isDistinct());
1202   Record.push_back(N->getTag());
1203   Record.push_back(0); // Per-tag version field; unused for now.
1204 
1205   for (auto &I : N->operands())
1206     Record.push_back(VE.getMetadataOrNullID(I));
1207 
1208   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1209   Record.clear();
1210 }
1211 
1212 static uint64_t rotateSign(int64_t I) {
1213   uint64_t U = I;
1214   return I < 0 ? ~(U << 1) : U << 1;
1215 }
1216 
1217 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1218                                           SmallVectorImpl<uint64_t> &Record,
1219                                           unsigned Abbrev) {
1220   Record.push_back(N->isDistinct());
1221   Record.push_back(N->getCount());
1222   Record.push_back(rotateSign(N->getLowerBound()));
1223 
1224   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1225   Record.clear();
1226 }
1227 
1228 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1229                                             SmallVectorImpl<uint64_t> &Record,
1230                                             unsigned Abbrev) {
1231   Record.push_back(N->isDistinct());
1232   Record.push_back(rotateSign(N->getValue()));
1233   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1234 
1235   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1236   Record.clear();
1237 }
1238 
1239 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1240                                            SmallVectorImpl<uint64_t> &Record,
1241                                            unsigned Abbrev) {
1242   Record.push_back(N->isDistinct());
1243   Record.push_back(N->getTag());
1244   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1245   Record.push_back(N->getSizeInBits());
1246   Record.push_back(N->getAlignInBits());
1247   Record.push_back(N->getEncoding());
1248 
1249   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1250   Record.clear();
1251 }
1252 
1253 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1254                                              SmallVectorImpl<uint64_t> &Record,
1255                                              unsigned Abbrev) {
1256   Record.push_back(N->isDistinct());
1257   Record.push_back(N->getTag());
1258   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1259   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1260   Record.push_back(N->getLine());
1261   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1262   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1263   Record.push_back(N->getSizeInBits());
1264   Record.push_back(N->getAlignInBits());
1265   Record.push_back(N->getOffsetInBits());
1266   Record.push_back(N->getFlags());
1267   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1268 
1269   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1270   Record.clear();
1271 }
1272 
1273 void ModuleBitcodeWriter::writeDICompositeType(
1274     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1275     unsigned Abbrev) {
1276   const unsigned IsNotUsedInOldTypeRef = 0x2;
1277   Record.push_back(IsNotUsedInOldTypeRef | N->isDistinct());
1278   Record.push_back(N->getTag());
1279   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1280   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1281   Record.push_back(N->getLine());
1282   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1283   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1284   Record.push_back(N->getSizeInBits());
1285   Record.push_back(N->getAlignInBits());
1286   Record.push_back(N->getOffsetInBits());
1287   Record.push_back(N->getFlags());
1288   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1289   Record.push_back(N->getRuntimeLang());
1290   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1291   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1292   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1293 
1294   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1295   Record.clear();
1296 }
1297 
1298 void ModuleBitcodeWriter::writeDISubroutineType(
1299     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1300     unsigned Abbrev) {
1301   const unsigned HasNoOldTypeRefs = 0x2;
1302   Record.push_back(HasNoOldTypeRefs | N->isDistinct());
1303   Record.push_back(N->getFlags());
1304   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1305 
1306   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1307   Record.clear();
1308 }
1309 
1310 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1311                                       SmallVectorImpl<uint64_t> &Record,
1312                                       unsigned Abbrev) {
1313   Record.push_back(N->isDistinct());
1314   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1315   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1316 
1317   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1318   Record.clear();
1319 }
1320 
1321 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1322                                              SmallVectorImpl<uint64_t> &Record,
1323                                              unsigned Abbrev) {
1324   assert(N->isDistinct() && "Expected distinct compile units");
1325   Record.push_back(/* IsDistinct */ true);
1326   Record.push_back(N->getSourceLanguage());
1327   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1328   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1329   Record.push_back(N->isOptimized());
1330   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1331   Record.push_back(N->getRuntimeVersion());
1332   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1333   Record.push_back(N->getEmissionKind());
1334   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1335   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1336   Record.push_back(/* subprograms */ 0);
1337   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1338   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1339   Record.push_back(N->getDWOId());
1340   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1341 
1342   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1343   Record.clear();
1344 }
1345 
1346 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1347                                             SmallVectorImpl<uint64_t> &Record,
1348                                             unsigned Abbrev) {
1349   Record.push_back(N->isDistinct());
1350   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1351   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1352   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1353   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1354   Record.push_back(N->getLine());
1355   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1356   Record.push_back(N->isLocalToUnit());
1357   Record.push_back(N->isDefinition());
1358   Record.push_back(N->getScopeLine());
1359   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1360   Record.push_back(N->getVirtuality());
1361   Record.push_back(N->getVirtualIndex());
1362   Record.push_back(N->getFlags());
1363   Record.push_back(N->isOptimized());
1364   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1365   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1366   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1367   Record.push_back(VE.getMetadataOrNullID(N->getVariables().get()));
1368 
1369   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1370   Record.clear();
1371 }
1372 
1373 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1374                                               SmallVectorImpl<uint64_t> &Record,
1375                                               unsigned Abbrev) {
1376   Record.push_back(N->isDistinct());
1377   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1378   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1379   Record.push_back(N->getLine());
1380   Record.push_back(N->getColumn());
1381 
1382   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1383   Record.clear();
1384 }
1385 
1386 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1387     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1388     unsigned Abbrev) {
1389   Record.push_back(N->isDistinct());
1390   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1391   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1392   Record.push_back(N->getDiscriminator());
1393 
1394   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1395   Record.clear();
1396 }
1397 
1398 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1399                                            SmallVectorImpl<uint64_t> &Record,
1400                                            unsigned Abbrev) {
1401   Record.push_back(N->isDistinct());
1402   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1403   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1404   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1405   Record.push_back(N->getLine());
1406 
1407   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1408   Record.clear();
1409 }
1410 
1411 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1412                                        SmallVectorImpl<uint64_t> &Record,
1413                                        unsigned Abbrev) {
1414   Record.push_back(N->isDistinct());
1415   Record.push_back(N->getMacinfoType());
1416   Record.push_back(N->getLine());
1417   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1418   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1419 
1420   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1421   Record.clear();
1422 }
1423 
1424 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1425                                            SmallVectorImpl<uint64_t> &Record,
1426                                            unsigned Abbrev) {
1427   Record.push_back(N->isDistinct());
1428   Record.push_back(N->getMacinfoType());
1429   Record.push_back(N->getLine());
1430   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1431   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1432 
1433   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1434   Record.clear();
1435 }
1436 
1437 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1438                                         SmallVectorImpl<uint64_t> &Record,
1439                                         unsigned Abbrev) {
1440   Record.push_back(N->isDistinct());
1441   for (auto &I : N->operands())
1442     Record.push_back(VE.getMetadataOrNullID(I));
1443 
1444   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1445   Record.clear();
1446 }
1447 
1448 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1449     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1450     unsigned Abbrev) {
1451   Record.push_back(N->isDistinct());
1452   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1453   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1454 
1455   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1456   Record.clear();
1457 }
1458 
1459 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1460     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1461     unsigned Abbrev) {
1462   Record.push_back(N->isDistinct());
1463   Record.push_back(N->getTag());
1464   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1465   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1466   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1467 
1468   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1469   Record.clear();
1470 }
1471 
1472 void ModuleBitcodeWriter::writeDIGlobalVariable(
1473     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1474     unsigned Abbrev) {
1475   Record.push_back(N->isDistinct());
1476   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1477   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1478   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1479   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1480   Record.push_back(N->getLine());
1481   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1482   Record.push_back(N->isLocalToUnit());
1483   Record.push_back(N->isDefinition());
1484   Record.push_back(VE.getMetadataOrNullID(N->getRawVariable()));
1485   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1486 
1487   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1488   Record.clear();
1489 }
1490 
1491 void ModuleBitcodeWriter::writeDILocalVariable(
1492     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
1493     unsigned Abbrev) {
1494   Record.push_back(N->isDistinct());
1495   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1496   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
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->getArg());
1501   Record.push_back(N->getFlags());
1502 
1503   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1504   Record.clear();
1505 }
1506 
1507 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
1508                                             SmallVectorImpl<uint64_t> &Record,
1509                                             unsigned Abbrev) {
1510   Record.reserve(N->getElements().size() + 1);
1511 
1512   Record.push_back(N->isDistinct());
1513   Record.append(N->elements_begin(), N->elements_end());
1514 
1515   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
1516   Record.clear();
1517 }
1518 
1519 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
1520                                               SmallVectorImpl<uint64_t> &Record,
1521                                               unsigned Abbrev) {
1522   Record.push_back(N->isDistinct());
1523   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1524   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1525   Record.push_back(N->getLine());
1526   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
1527   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
1528   Record.push_back(N->getAttributes());
1529   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1530 
1531   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
1532   Record.clear();
1533 }
1534 
1535 void ModuleBitcodeWriter::writeDIImportedEntity(
1536     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
1537     unsigned Abbrev) {
1538   Record.push_back(N->isDistinct());
1539   Record.push_back(N->getTag());
1540   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1541   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
1542   Record.push_back(N->getLine());
1543   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1544 
1545   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
1546   Record.clear();
1547 }
1548 
1549 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
1550   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1551   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
1552   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1553   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1554   return Stream.EmitAbbrev(Abbv);
1555 }
1556 
1557 void ModuleBitcodeWriter::writeNamedMetadata(
1558     SmallVectorImpl<uint64_t> &Record) {
1559   if (M.named_metadata_empty())
1560     return;
1561 
1562   unsigned Abbrev = createNamedMetadataAbbrev();
1563   for (const NamedMDNode &NMD : M.named_metadata()) {
1564     // Write name.
1565     StringRef Str = NMD.getName();
1566     Record.append(Str.bytes_begin(), Str.bytes_end());
1567     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
1568     Record.clear();
1569 
1570     // Write named metadata operands.
1571     for (const MDNode *N : NMD.operands())
1572       Record.push_back(VE.getMetadataID(N));
1573     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
1574     Record.clear();
1575   }
1576 }
1577 
1578 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
1579   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1580   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
1581   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
1582   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
1583   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
1584   return Stream.EmitAbbrev(Abbv);
1585 }
1586 
1587 /// Write out a record for MDString.
1588 ///
1589 /// All the metadata strings in a metadata block are emitted in a single
1590 /// record.  The sizes and strings themselves are shoved into a blob.
1591 void ModuleBitcodeWriter::writeMetadataStrings(
1592     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
1593   if (Strings.empty())
1594     return;
1595 
1596   // Start the record with the number of strings.
1597   Record.push_back(bitc::METADATA_STRINGS);
1598   Record.push_back(Strings.size());
1599 
1600   // Emit the sizes of the strings in the blob.
1601   SmallString<256> Blob;
1602   {
1603     BitstreamWriter W(Blob);
1604     for (const Metadata *MD : Strings)
1605       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
1606     W.FlushToWord();
1607   }
1608 
1609   // Add the offset to the strings to the record.
1610   Record.push_back(Blob.size());
1611 
1612   // Add the strings to the blob.
1613   for (const Metadata *MD : Strings)
1614     Blob.append(cast<MDString>(MD)->getString());
1615 
1616   // Emit the final record.
1617   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
1618   Record.clear();
1619 }
1620 
1621 void ModuleBitcodeWriter::writeMetadataRecords(
1622     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record) {
1623   if (MDs.empty())
1624     return;
1625 
1626   // Initialize MDNode abbreviations.
1627 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
1628 #include "llvm/IR/Metadata.def"
1629 
1630   for (const Metadata *MD : MDs) {
1631     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
1632       assert(N->isResolved() && "Expected forward references to be resolved");
1633 
1634       switch (N->getMetadataID()) {
1635       default:
1636         llvm_unreachable("Invalid MDNode subclass");
1637 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
1638   case Metadata::CLASS##Kind:                                                  \
1639     write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                       \
1640     continue;
1641 #include "llvm/IR/Metadata.def"
1642       }
1643     }
1644     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
1645   }
1646 }
1647 
1648 void ModuleBitcodeWriter::writeModuleMetadata() {
1649   if (!VE.hasMDs() && M.named_metadata_empty())
1650     return;
1651 
1652   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1653   SmallVector<uint64_t, 64> Record;
1654   writeMetadataStrings(VE.getMDStrings(), Record);
1655   writeMetadataRecords(VE.getNonMDStrings(), Record);
1656   writeNamedMetadata(Record);
1657   Stream.ExitBlock();
1658 }
1659 
1660 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
1661   if (!VE.hasMDs())
1662     return;
1663 
1664   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1665   SmallVector<uint64_t, 64> Record;
1666   writeMetadataStrings(VE.getMDStrings(), Record);
1667   writeMetadataRecords(VE.getNonMDStrings(), Record);
1668   Stream.ExitBlock();
1669 }
1670 
1671 void ModuleBitcodeWriter::writeMetadataAttachment(const Function &F) {
1672   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
1673 
1674   SmallVector<uint64_t, 64> Record;
1675 
1676   // Write metadata attachments
1677   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
1678   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
1679   F.getAllMetadata(MDs);
1680   if (!MDs.empty()) {
1681     for (const auto &I : MDs) {
1682       Record.push_back(I.first);
1683       Record.push_back(VE.getMetadataID(I.second));
1684     }
1685     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1686     Record.clear();
1687   }
1688 
1689   for (const BasicBlock &BB : F)
1690     for (const Instruction &I : BB) {
1691       MDs.clear();
1692       I.getAllMetadataOtherThanDebugLoc(MDs);
1693 
1694       // If no metadata, ignore instruction.
1695       if (MDs.empty()) continue;
1696 
1697       Record.push_back(VE.getInstructionID(&I));
1698 
1699       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1700         Record.push_back(MDs[i].first);
1701         Record.push_back(VE.getMetadataID(MDs[i].second));
1702       }
1703       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1704       Record.clear();
1705     }
1706 
1707   Stream.ExitBlock();
1708 }
1709 
1710 void ModuleBitcodeWriter::writeModuleMetadataStore() {
1711   SmallVector<uint64_t, 64> Record;
1712 
1713   // Write metadata kinds
1714   // METADATA_KIND - [n x [id, name]]
1715   SmallVector<StringRef, 8> Names;
1716   M.getMDKindNames(Names);
1717 
1718   if (Names.empty()) return;
1719 
1720   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
1721 
1722   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
1723     Record.push_back(MDKindID);
1724     StringRef KName = Names[MDKindID];
1725     Record.append(KName.begin(), KName.end());
1726 
1727     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
1728     Record.clear();
1729   }
1730 
1731   Stream.ExitBlock();
1732 }
1733 
1734 void ModuleBitcodeWriter::writeOperandBundleTags() {
1735   // Write metadata kinds
1736   //
1737   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
1738   //
1739   // OPERAND_BUNDLE_TAG - [strchr x N]
1740 
1741   SmallVector<StringRef, 8> Tags;
1742   M.getOperandBundleTags(Tags);
1743 
1744   if (Tags.empty())
1745     return;
1746 
1747   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
1748 
1749   SmallVector<uint64_t, 64> Record;
1750 
1751   for (auto Tag : Tags) {
1752     Record.append(Tag.begin(), Tag.end());
1753 
1754     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
1755     Record.clear();
1756   }
1757 
1758   Stream.ExitBlock();
1759 }
1760 
1761 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1762   if ((int64_t)V >= 0)
1763     Vals.push_back(V << 1);
1764   else
1765     Vals.push_back((-V << 1) | 1);
1766 }
1767 
1768 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
1769                                          bool isGlobal) {
1770   if (FirstVal == LastVal) return;
1771 
1772   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
1773 
1774   unsigned AggregateAbbrev = 0;
1775   unsigned String8Abbrev = 0;
1776   unsigned CString7Abbrev = 0;
1777   unsigned CString6Abbrev = 0;
1778   // If this is a constant pool for the module, emit module-specific abbrevs.
1779   if (isGlobal) {
1780     // Abbrev for CST_CODE_AGGREGATE.
1781     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1782     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
1783     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1784     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
1785     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
1786 
1787     // Abbrev for CST_CODE_STRING.
1788     Abbv = new BitCodeAbbrev();
1789     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
1790     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1791     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1792     String8Abbrev = Stream.EmitAbbrev(Abbv);
1793     // Abbrev for CST_CODE_CSTRING.
1794     Abbv = new BitCodeAbbrev();
1795     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1796     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1797     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1798     CString7Abbrev = Stream.EmitAbbrev(Abbv);
1799     // Abbrev for CST_CODE_CSTRING.
1800     Abbv = new BitCodeAbbrev();
1801     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1802     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1803     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1804     CString6Abbrev = Stream.EmitAbbrev(Abbv);
1805   }
1806 
1807   SmallVector<uint64_t, 64> Record;
1808 
1809   const ValueEnumerator::ValueList &Vals = VE.getValues();
1810   Type *LastTy = nullptr;
1811   for (unsigned i = FirstVal; i != LastVal; ++i) {
1812     const Value *V = Vals[i].first;
1813     // If we need to switch types, do so now.
1814     if (V->getType() != LastTy) {
1815       LastTy = V->getType();
1816       Record.push_back(VE.getTypeID(LastTy));
1817       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
1818                         CONSTANTS_SETTYPE_ABBREV);
1819       Record.clear();
1820     }
1821 
1822     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
1823       Record.push_back(unsigned(IA->hasSideEffects()) |
1824                        unsigned(IA->isAlignStack()) << 1 |
1825                        unsigned(IA->getDialect()&1) << 2);
1826 
1827       // Add the asm string.
1828       const std::string &AsmStr = IA->getAsmString();
1829       Record.push_back(AsmStr.size());
1830       Record.append(AsmStr.begin(), AsmStr.end());
1831 
1832       // Add the constraint string.
1833       const std::string &ConstraintStr = IA->getConstraintString();
1834       Record.push_back(ConstraintStr.size());
1835       Record.append(ConstraintStr.begin(), ConstraintStr.end());
1836       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
1837       Record.clear();
1838       continue;
1839     }
1840     const Constant *C = cast<Constant>(V);
1841     unsigned Code = -1U;
1842     unsigned AbbrevToUse = 0;
1843     if (C->isNullValue()) {
1844       Code = bitc::CST_CODE_NULL;
1845     } else if (isa<UndefValue>(C)) {
1846       Code = bitc::CST_CODE_UNDEF;
1847     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
1848       if (IV->getBitWidth() <= 64) {
1849         uint64_t V = IV->getSExtValue();
1850         emitSignedInt64(Record, V);
1851         Code = bitc::CST_CODE_INTEGER;
1852         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
1853       } else {                             // Wide integers, > 64 bits in size.
1854         // We have an arbitrary precision integer value to write whose
1855         // bit width is > 64. However, in canonical unsigned integer
1856         // format it is likely that the high bits are going to be zero.
1857         // So, we only write the number of active words.
1858         unsigned NWords = IV->getValue().getActiveWords();
1859         const uint64_t *RawWords = IV->getValue().getRawData();
1860         for (unsigned i = 0; i != NWords; ++i) {
1861           emitSignedInt64(Record, RawWords[i]);
1862         }
1863         Code = bitc::CST_CODE_WIDE_INTEGER;
1864       }
1865     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
1866       Code = bitc::CST_CODE_FLOAT;
1867       Type *Ty = CFP->getType();
1868       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
1869         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
1870       } else if (Ty->isX86_FP80Ty()) {
1871         // api needed to prevent premature destruction
1872         // bits are not in the same order as a normal i80 APInt, compensate.
1873         APInt api = CFP->getValueAPF().bitcastToAPInt();
1874         const uint64_t *p = api.getRawData();
1875         Record.push_back((p[1] << 48) | (p[0] >> 16));
1876         Record.push_back(p[0] & 0xffffLL);
1877       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
1878         APInt api = CFP->getValueAPF().bitcastToAPInt();
1879         const uint64_t *p = api.getRawData();
1880         Record.push_back(p[0]);
1881         Record.push_back(p[1]);
1882       } else {
1883         assert (0 && "Unknown FP type!");
1884       }
1885     } else if (isa<ConstantDataSequential>(C) &&
1886                cast<ConstantDataSequential>(C)->isString()) {
1887       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
1888       // Emit constant strings specially.
1889       unsigned NumElts = Str->getNumElements();
1890       // If this is a null-terminated string, use the denser CSTRING encoding.
1891       if (Str->isCString()) {
1892         Code = bitc::CST_CODE_CSTRING;
1893         --NumElts;  // Don't encode the null, which isn't allowed by char6.
1894       } else {
1895         Code = bitc::CST_CODE_STRING;
1896         AbbrevToUse = String8Abbrev;
1897       }
1898       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
1899       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
1900       for (unsigned i = 0; i != NumElts; ++i) {
1901         unsigned char V = Str->getElementAsInteger(i);
1902         Record.push_back(V);
1903         isCStr7 &= (V & 128) == 0;
1904         if (isCStrChar6)
1905           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
1906       }
1907 
1908       if (isCStrChar6)
1909         AbbrevToUse = CString6Abbrev;
1910       else if (isCStr7)
1911         AbbrevToUse = CString7Abbrev;
1912     } else if (const ConstantDataSequential *CDS =
1913                   dyn_cast<ConstantDataSequential>(C)) {
1914       Code = bitc::CST_CODE_DATA;
1915       Type *EltTy = CDS->getType()->getElementType();
1916       if (isa<IntegerType>(EltTy)) {
1917         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
1918           Record.push_back(CDS->getElementAsInteger(i));
1919       } else {
1920         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
1921           Record.push_back(
1922               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
1923       }
1924     } else if (isa<ConstantAggregate>(C)) {
1925       Code = bitc::CST_CODE_AGGREGATE;
1926       for (const Value *Op : C->operands())
1927         Record.push_back(VE.getValueID(Op));
1928       AbbrevToUse = AggregateAbbrev;
1929     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
1930       switch (CE->getOpcode()) {
1931       default:
1932         if (Instruction::isCast(CE->getOpcode())) {
1933           Code = bitc::CST_CODE_CE_CAST;
1934           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
1935           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1936           Record.push_back(VE.getValueID(C->getOperand(0)));
1937           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
1938         } else {
1939           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
1940           Code = bitc::CST_CODE_CE_BINOP;
1941           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
1942           Record.push_back(VE.getValueID(C->getOperand(0)));
1943           Record.push_back(VE.getValueID(C->getOperand(1)));
1944           uint64_t Flags = getOptimizationFlags(CE);
1945           if (Flags != 0)
1946             Record.push_back(Flags);
1947         }
1948         break;
1949       case Instruction::GetElementPtr: {
1950         Code = bitc::CST_CODE_CE_GEP;
1951         const auto *GO = cast<GEPOperator>(C);
1952         if (GO->isInBounds())
1953           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
1954         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
1955         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
1956           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
1957           Record.push_back(VE.getValueID(C->getOperand(i)));
1958         }
1959         break;
1960       }
1961       case Instruction::Select:
1962         Code = bitc::CST_CODE_CE_SELECT;
1963         Record.push_back(VE.getValueID(C->getOperand(0)));
1964         Record.push_back(VE.getValueID(C->getOperand(1)));
1965         Record.push_back(VE.getValueID(C->getOperand(2)));
1966         break;
1967       case Instruction::ExtractElement:
1968         Code = bitc::CST_CODE_CE_EXTRACTELT;
1969         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1970         Record.push_back(VE.getValueID(C->getOperand(0)));
1971         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
1972         Record.push_back(VE.getValueID(C->getOperand(1)));
1973         break;
1974       case Instruction::InsertElement:
1975         Code = bitc::CST_CODE_CE_INSERTELT;
1976         Record.push_back(VE.getValueID(C->getOperand(0)));
1977         Record.push_back(VE.getValueID(C->getOperand(1)));
1978         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
1979         Record.push_back(VE.getValueID(C->getOperand(2)));
1980         break;
1981       case Instruction::ShuffleVector:
1982         // If the return type and argument types are the same, this is a
1983         // standard shufflevector instruction.  If the types are different,
1984         // then the shuffle is widening or truncating the input vectors, and
1985         // the argument type must also be encoded.
1986         if (C->getType() == C->getOperand(0)->getType()) {
1987           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
1988         } else {
1989           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
1990           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1991         }
1992         Record.push_back(VE.getValueID(C->getOperand(0)));
1993         Record.push_back(VE.getValueID(C->getOperand(1)));
1994         Record.push_back(VE.getValueID(C->getOperand(2)));
1995         break;
1996       case Instruction::ICmp:
1997       case Instruction::FCmp:
1998         Code = bitc::CST_CODE_CE_CMP;
1999         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2000         Record.push_back(VE.getValueID(C->getOperand(0)));
2001         Record.push_back(VE.getValueID(C->getOperand(1)));
2002         Record.push_back(CE->getPredicate());
2003         break;
2004       }
2005     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2006       Code = bitc::CST_CODE_BLOCKADDRESS;
2007       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2008       Record.push_back(VE.getValueID(BA->getFunction()));
2009       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2010     } else {
2011 #ifndef NDEBUG
2012       C->dump();
2013 #endif
2014       llvm_unreachable("Unknown constant!");
2015     }
2016     Stream.EmitRecord(Code, Record, AbbrevToUse);
2017     Record.clear();
2018   }
2019 
2020   Stream.ExitBlock();
2021 }
2022 
2023 void ModuleBitcodeWriter::writeModuleConstants() {
2024   const ValueEnumerator::ValueList &Vals = VE.getValues();
2025 
2026   // Find the first constant to emit, which is the first non-globalvalue value.
2027   // We know globalvalues have been emitted by WriteModuleInfo.
2028   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2029     if (!isa<GlobalValue>(Vals[i].first)) {
2030       writeConstants(i, Vals.size(), true);
2031       return;
2032     }
2033   }
2034 }
2035 
2036 /// pushValueAndType - The file has to encode both the value and type id for
2037 /// many values, because we need to know what type to create for forward
2038 /// references.  However, most operands are not forward references, so this type
2039 /// field is not needed.
2040 ///
2041 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2042 /// instruction ID, then it is a forward reference, and it also includes the
2043 /// type ID.  The value ID that is written is encoded relative to the InstID.
2044 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2045                                            SmallVectorImpl<unsigned> &Vals) {
2046   unsigned ValID = VE.getValueID(V);
2047   // Make encoding relative to the InstID.
2048   Vals.push_back(InstID - ValID);
2049   if (ValID >= InstID) {
2050     Vals.push_back(VE.getTypeID(V->getType()));
2051     return true;
2052   }
2053   return false;
2054 }
2055 
2056 void ModuleBitcodeWriter::writeOperandBundles(ImmutableCallSite CS,
2057                                               unsigned InstID) {
2058   SmallVector<unsigned, 64> Record;
2059   LLVMContext &C = CS.getInstruction()->getContext();
2060 
2061   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2062     const auto &Bundle = CS.getOperandBundleAt(i);
2063     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2064 
2065     for (auto &Input : Bundle.Inputs)
2066       pushValueAndType(Input, InstID, Record);
2067 
2068     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2069     Record.clear();
2070   }
2071 }
2072 
2073 /// pushValue - Like pushValueAndType, but where the type of the value is
2074 /// omitted (perhaps it was already encoded in an earlier operand).
2075 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2076                                     SmallVectorImpl<unsigned> &Vals) {
2077   unsigned ValID = VE.getValueID(V);
2078   Vals.push_back(InstID - ValID);
2079 }
2080 
2081 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2082                                           SmallVectorImpl<uint64_t> &Vals) {
2083   unsigned ValID = VE.getValueID(V);
2084   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2085   emitSignedInt64(Vals, diff);
2086 }
2087 
2088 /// WriteInstruction - Emit an instruction to the specified stream.
2089 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2090                                            unsigned InstID,
2091                                            SmallVectorImpl<unsigned> &Vals) {
2092   unsigned Code = 0;
2093   unsigned AbbrevToUse = 0;
2094   VE.setInstructionID(&I);
2095   switch (I.getOpcode()) {
2096   default:
2097     if (Instruction::isCast(I.getOpcode())) {
2098       Code = bitc::FUNC_CODE_INST_CAST;
2099       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2100         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2101       Vals.push_back(VE.getTypeID(I.getType()));
2102       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2103     } else {
2104       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2105       Code = bitc::FUNC_CODE_INST_BINOP;
2106       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2107         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2108       pushValue(I.getOperand(1), InstID, Vals);
2109       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2110       uint64_t Flags = getOptimizationFlags(&I);
2111       if (Flags != 0) {
2112         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2113           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2114         Vals.push_back(Flags);
2115       }
2116     }
2117     break;
2118 
2119   case Instruction::GetElementPtr: {
2120     Code = bitc::FUNC_CODE_INST_GEP;
2121     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2122     auto &GEPInst = cast<GetElementPtrInst>(I);
2123     Vals.push_back(GEPInst.isInBounds());
2124     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2125     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2126       pushValueAndType(I.getOperand(i), InstID, Vals);
2127     break;
2128   }
2129   case Instruction::ExtractValue: {
2130     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2131     pushValueAndType(I.getOperand(0), InstID, Vals);
2132     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2133     Vals.append(EVI->idx_begin(), EVI->idx_end());
2134     break;
2135   }
2136   case Instruction::InsertValue: {
2137     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2138     pushValueAndType(I.getOperand(0), InstID, Vals);
2139     pushValueAndType(I.getOperand(1), InstID, Vals);
2140     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2141     Vals.append(IVI->idx_begin(), IVI->idx_end());
2142     break;
2143   }
2144   case Instruction::Select:
2145     Code = bitc::FUNC_CODE_INST_VSELECT;
2146     pushValueAndType(I.getOperand(1), InstID, Vals);
2147     pushValue(I.getOperand(2), InstID, Vals);
2148     pushValueAndType(I.getOperand(0), InstID, Vals);
2149     break;
2150   case Instruction::ExtractElement:
2151     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2152     pushValueAndType(I.getOperand(0), InstID, Vals);
2153     pushValueAndType(I.getOperand(1), InstID, Vals);
2154     break;
2155   case Instruction::InsertElement:
2156     Code = bitc::FUNC_CODE_INST_INSERTELT;
2157     pushValueAndType(I.getOperand(0), InstID, Vals);
2158     pushValue(I.getOperand(1), InstID, Vals);
2159     pushValueAndType(I.getOperand(2), InstID, Vals);
2160     break;
2161   case Instruction::ShuffleVector:
2162     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2163     pushValueAndType(I.getOperand(0), InstID, Vals);
2164     pushValue(I.getOperand(1), InstID, Vals);
2165     pushValue(I.getOperand(2), InstID, Vals);
2166     break;
2167   case Instruction::ICmp:
2168   case Instruction::FCmp: {
2169     // compare returning Int1Ty or vector of Int1Ty
2170     Code = bitc::FUNC_CODE_INST_CMP2;
2171     pushValueAndType(I.getOperand(0), InstID, Vals);
2172     pushValue(I.getOperand(1), InstID, Vals);
2173     Vals.push_back(cast<CmpInst>(I).getPredicate());
2174     uint64_t Flags = getOptimizationFlags(&I);
2175     if (Flags != 0)
2176       Vals.push_back(Flags);
2177     break;
2178   }
2179 
2180   case Instruction::Ret:
2181     {
2182       Code = bitc::FUNC_CODE_INST_RET;
2183       unsigned NumOperands = I.getNumOperands();
2184       if (NumOperands == 0)
2185         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2186       else if (NumOperands == 1) {
2187         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2188           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2189       } else {
2190         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2191           pushValueAndType(I.getOperand(i), InstID, Vals);
2192       }
2193     }
2194     break;
2195   case Instruction::Br:
2196     {
2197       Code = bitc::FUNC_CODE_INST_BR;
2198       const BranchInst &II = cast<BranchInst>(I);
2199       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2200       if (II.isConditional()) {
2201         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2202         pushValue(II.getCondition(), InstID, Vals);
2203       }
2204     }
2205     break;
2206   case Instruction::Switch:
2207     {
2208       Code = bitc::FUNC_CODE_INST_SWITCH;
2209       const SwitchInst &SI = cast<SwitchInst>(I);
2210       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2211       pushValue(SI.getCondition(), InstID, Vals);
2212       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2213       for (SwitchInst::ConstCaseIt Case : SI.cases()) {
2214         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2215         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2216       }
2217     }
2218     break;
2219   case Instruction::IndirectBr:
2220     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2221     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2222     // Encode the address operand as relative, but not the basic blocks.
2223     pushValue(I.getOperand(0), InstID, Vals);
2224     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2225       Vals.push_back(VE.getValueID(I.getOperand(i)));
2226     break;
2227 
2228   case Instruction::Invoke: {
2229     const InvokeInst *II = cast<InvokeInst>(&I);
2230     const Value *Callee = II->getCalledValue();
2231     FunctionType *FTy = II->getFunctionType();
2232 
2233     if (II->hasOperandBundles())
2234       writeOperandBundles(II, InstID);
2235 
2236     Code = bitc::FUNC_CODE_INST_INVOKE;
2237 
2238     Vals.push_back(VE.getAttributeID(II->getAttributes()));
2239     Vals.push_back(II->getCallingConv() | 1 << 13);
2240     Vals.push_back(VE.getValueID(II->getNormalDest()));
2241     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2242     Vals.push_back(VE.getTypeID(FTy));
2243     pushValueAndType(Callee, InstID, Vals);
2244 
2245     // Emit value #'s for the fixed parameters.
2246     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2247       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2248 
2249     // Emit type/value pairs for varargs params.
2250     if (FTy->isVarArg()) {
2251       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
2252            i != e; ++i)
2253         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2254     }
2255     break;
2256   }
2257   case Instruction::Resume:
2258     Code = bitc::FUNC_CODE_INST_RESUME;
2259     pushValueAndType(I.getOperand(0), InstID, Vals);
2260     break;
2261   case Instruction::CleanupRet: {
2262     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2263     const auto &CRI = cast<CleanupReturnInst>(I);
2264     pushValue(CRI.getCleanupPad(), InstID, Vals);
2265     if (CRI.hasUnwindDest())
2266       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2267     break;
2268   }
2269   case Instruction::CatchRet: {
2270     Code = bitc::FUNC_CODE_INST_CATCHRET;
2271     const auto &CRI = cast<CatchReturnInst>(I);
2272     pushValue(CRI.getCatchPad(), InstID, Vals);
2273     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2274     break;
2275   }
2276   case Instruction::CleanupPad:
2277   case Instruction::CatchPad: {
2278     const auto &FuncletPad = cast<FuncletPadInst>(I);
2279     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2280                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2281     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2282 
2283     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2284     Vals.push_back(NumArgOperands);
2285     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2286       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2287     break;
2288   }
2289   case Instruction::CatchSwitch: {
2290     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2291     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2292 
2293     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2294 
2295     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2296     Vals.push_back(NumHandlers);
2297     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2298       Vals.push_back(VE.getValueID(CatchPadBB));
2299 
2300     if (CatchSwitch.hasUnwindDest())
2301       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
2302     break;
2303   }
2304   case Instruction::Unreachable:
2305     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
2306     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
2307     break;
2308 
2309   case Instruction::PHI: {
2310     const PHINode &PN = cast<PHINode>(I);
2311     Code = bitc::FUNC_CODE_INST_PHI;
2312     // With the newer instruction encoding, forward references could give
2313     // negative valued IDs.  This is most common for PHIs, so we use
2314     // signed VBRs.
2315     SmallVector<uint64_t, 128> Vals64;
2316     Vals64.push_back(VE.getTypeID(PN.getType()));
2317     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
2318       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
2319       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
2320     }
2321     // Emit a Vals64 vector and exit.
2322     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
2323     Vals64.clear();
2324     return;
2325   }
2326 
2327   case Instruction::LandingPad: {
2328     const LandingPadInst &LP = cast<LandingPadInst>(I);
2329     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
2330     Vals.push_back(VE.getTypeID(LP.getType()));
2331     Vals.push_back(LP.isCleanup());
2332     Vals.push_back(LP.getNumClauses());
2333     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
2334       if (LP.isCatch(I))
2335         Vals.push_back(LandingPadInst::Catch);
2336       else
2337         Vals.push_back(LandingPadInst::Filter);
2338       pushValueAndType(LP.getClause(I), InstID, Vals);
2339     }
2340     break;
2341   }
2342 
2343   case Instruction::Alloca: {
2344     Code = bitc::FUNC_CODE_INST_ALLOCA;
2345     const AllocaInst &AI = cast<AllocaInst>(I);
2346     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
2347     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2348     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
2349     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
2350     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
2351            "not enough bits for maximum alignment");
2352     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
2353     AlignRecord |= AI.isUsedWithInAlloca() << 5;
2354     AlignRecord |= 1 << 6;
2355     AlignRecord |= AI.isSwiftError() << 7;
2356     Vals.push_back(AlignRecord);
2357     break;
2358   }
2359 
2360   case Instruction::Load:
2361     if (cast<LoadInst>(I).isAtomic()) {
2362       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
2363       pushValueAndType(I.getOperand(0), InstID, Vals);
2364     } else {
2365       Code = bitc::FUNC_CODE_INST_LOAD;
2366       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
2367         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
2368     }
2369     Vals.push_back(VE.getTypeID(I.getType()));
2370     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
2371     Vals.push_back(cast<LoadInst>(I).isVolatile());
2372     if (cast<LoadInst>(I).isAtomic()) {
2373       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
2374       Vals.push_back(getEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
2375     }
2376     break;
2377   case Instruction::Store:
2378     if (cast<StoreInst>(I).isAtomic())
2379       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
2380     else
2381       Code = bitc::FUNC_CODE_INST_STORE;
2382     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
2383     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
2384     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
2385     Vals.push_back(cast<StoreInst>(I).isVolatile());
2386     if (cast<StoreInst>(I).isAtomic()) {
2387       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
2388       Vals.push_back(getEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
2389     }
2390     break;
2391   case Instruction::AtomicCmpXchg:
2392     Code = bitc::FUNC_CODE_INST_CMPXCHG;
2393     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
2394     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
2395     pushValue(I.getOperand(2), InstID, Vals);        // newval.
2396     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
2397     Vals.push_back(
2398         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
2399     Vals.push_back(
2400         getEncodedSynchScope(cast<AtomicCmpXchgInst>(I).getSynchScope()));
2401     Vals.push_back(
2402         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
2403     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
2404     break;
2405   case Instruction::AtomicRMW:
2406     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
2407     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
2408     pushValue(I.getOperand(1), InstID, Vals);        // val.
2409     Vals.push_back(
2410         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
2411     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
2412     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
2413     Vals.push_back(
2414         getEncodedSynchScope(cast<AtomicRMWInst>(I).getSynchScope()));
2415     break;
2416   case Instruction::Fence:
2417     Code = bitc::FUNC_CODE_INST_FENCE;
2418     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
2419     Vals.push_back(getEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
2420     break;
2421   case Instruction::Call: {
2422     const CallInst &CI = cast<CallInst>(I);
2423     FunctionType *FTy = CI.getFunctionType();
2424 
2425     if (CI.hasOperandBundles())
2426       writeOperandBundles(&CI, InstID);
2427 
2428     Code = bitc::FUNC_CODE_INST_CALL;
2429 
2430     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
2431 
2432     unsigned Flags = getOptimizationFlags(&I);
2433     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
2434                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
2435                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
2436                    1 << bitc::CALL_EXPLICIT_TYPE |
2437                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
2438                    unsigned(Flags != 0) << bitc::CALL_FMF);
2439     if (Flags != 0)
2440       Vals.push_back(Flags);
2441 
2442     Vals.push_back(VE.getTypeID(FTy));
2443     pushValueAndType(CI.getCalledValue(), InstID, Vals); // Callee
2444 
2445     // Emit value #'s for the fixed parameters.
2446     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
2447       // Check for labels (can happen with asm labels).
2448       if (FTy->getParamType(i)->isLabelTy())
2449         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
2450       else
2451         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
2452     }
2453 
2454     // Emit type/value pairs for varargs params.
2455     if (FTy->isVarArg()) {
2456       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
2457            i != e; ++i)
2458         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
2459     }
2460     break;
2461   }
2462   case Instruction::VAArg:
2463     Code = bitc::FUNC_CODE_INST_VAARG;
2464     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
2465     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
2466     Vals.push_back(VE.getTypeID(I.getType())); // restype.
2467     break;
2468   }
2469 
2470   Stream.EmitRecord(Code, Vals, AbbrevToUse);
2471   Vals.clear();
2472 }
2473 
2474 /// Emit names for globals/functions etc. \p IsModuleLevel is true when
2475 /// we are writing the module-level VST, where we are including a function
2476 /// bitcode index and need to backpatch the VST forward declaration record.
2477 void ModuleBitcodeWriter::writeValueSymbolTable(
2478     const ValueSymbolTable &VST, bool IsModuleLevel,
2479     DenseMap<const Function *, uint64_t> *FunctionToBitcodeIndex) {
2480   if (VST.empty()) {
2481     // writeValueSymbolTableForwardDecl should have returned early as
2482     // well. Ensure this handling remains in sync by asserting that
2483     // the placeholder offset is not set.
2484     assert(!IsModuleLevel || !hasVSTOffsetPlaceholder());
2485     return;
2486   }
2487 
2488   if (IsModuleLevel && hasVSTOffsetPlaceholder()) {
2489     // Get the offset of the VST we are writing, and backpatch it into
2490     // the VST forward declaration record.
2491     uint64_t VSTOffset = Stream.GetCurrentBitNo();
2492     // The BitcodeStartBit was the stream offset of the actual bitcode
2493     // (e.g. excluding any initial darwin header).
2494     VSTOffset -= bitcodeStartBit();
2495     assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
2496     Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32);
2497   }
2498 
2499   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
2500 
2501   // For the module-level VST, add abbrev Ids for the VST_CODE_FNENTRY
2502   // records, which are not used in the per-function VSTs.
2503   unsigned FnEntry8BitAbbrev;
2504   unsigned FnEntry7BitAbbrev;
2505   unsigned FnEntry6BitAbbrev;
2506   if (IsModuleLevel && hasVSTOffsetPlaceholder()) {
2507     // 8-bit fixed-width VST_CODE_FNENTRY function strings.
2508     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2509     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2510     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2511     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2512     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2513     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2514     FnEntry8BitAbbrev = Stream.EmitAbbrev(Abbv);
2515 
2516     // 7-bit fixed width VST_CODE_FNENTRY function strings.
2517     Abbv = new BitCodeAbbrev();
2518     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2519     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2520     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2521     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2522     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2523     FnEntry7BitAbbrev = Stream.EmitAbbrev(Abbv);
2524 
2525     // 6-bit char6 VST_CODE_FNENTRY function strings.
2526     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::Char6));
2532     FnEntry6BitAbbrev = Stream.EmitAbbrev(Abbv);
2533   }
2534 
2535   // FIXME: Set up the abbrev, we know how many values there are!
2536   // FIXME: We know if the type names can use 7-bit ascii.
2537   SmallVector<unsigned, 64> NameVals;
2538 
2539   for (const ValueName &Name : VST) {
2540     // Figure out the encoding to use for the name.
2541     StringEncoding Bits =
2542         getStringEncoding(Name.getKeyData(), Name.getKeyLength());
2543 
2544     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
2545     NameVals.push_back(VE.getValueID(Name.getValue()));
2546 
2547     Function *F = dyn_cast<Function>(Name.getValue());
2548     if (!F) {
2549       // If value is an alias, need to get the aliased base object to
2550       // see if it is a function.
2551       auto *GA = dyn_cast<GlobalAlias>(Name.getValue());
2552       if (GA && GA->getBaseObject())
2553         F = dyn_cast<Function>(GA->getBaseObject());
2554     }
2555 
2556     // VST_CODE_ENTRY:   [valueid, namechar x N]
2557     // VST_CODE_FNENTRY: [valueid, funcoffset, namechar x N]
2558     // VST_CODE_BBENTRY: [bbid, namechar x N]
2559     unsigned Code;
2560     if (isa<BasicBlock>(Name.getValue())) {
2561       Code = bitc::VST_CODE_BBENTRY;
2562       if (Bits == SE_Char6)
2563         AbbrevToUse = VST_BBENTRY_6_ABBREV;
2564     } else if (F && !F->isDeclaration()) {
2565       // Must be the module-level VST, where we pass in the Index and
2566       // have a VSTOffsetPlaceholder. The function-level VST should not
2567       // contain any Function symbols.
2568       assert(FunctionToBitcodeIndex);
2569       assert(hasVSTOffsetPlaceholder());
2570 
2571       // Save the word offset of the function (from the start of the
2572       // actual bitcode written to the stream).
2573       uint64_t BitcodeIndex = (*FunctionToBitcodeIndex)[F] - bitcodeStartBit();
2574       assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
2575       NameVals.push_back(BitcodeIndex / 32);
2576 
2577       Code = bitc::VST_CODE_FNENTRY;
2578       AbbrevToUse = FnEntry8BitAbbrev;
2579       if (Bits == SE_Char6)
2580         AbbrevToUse = FnEntry6BitAbbrev;
2581       else if (Bits == SE_Fixed7)
2582         AbbrevToUse = FnEntry7BitAbbrev;
2583     } else {
2584       Code = bitc::VST_CODE_ENTRY;
2585       if (Bits == SE_Char6)
2586         AbbrevToUse = VST_ENTRY_6_ABBREV;
2587       else if (Bits == SE_Fixed7)
2588         AbbrevToUse = VST_ENTRY_7_ABBREV;
2589     }
2590 
2591     for (const auto P : Name.getKey())
2592       NameVals.push_back((unsigned char)P);
2593 
2594     // Emit the finished record.
2595     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
2596     NameVals.clear();
2597   }
2598   Stream.ExitBlock();
2599 }
2600 
2601 /// Emit function names and summary offsets for the combined index
2602 /// used by ThinLTO.
2603 void IndexBitcodeWriter::writeCombinedValueSymbolTable() {
2604   assert(hasVSTOffsetPlaceholder() && "Expected non-zero VSTOffsetPlaceholder");
2605   // Get the offset of the VST we are writing, and backpatch it into
2606   // the VST forward declaration record.
2607   uint64_t VSTOffset = Stream.GetCurrentBitNo();
2608   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
2609   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32);
2610 
2611   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
2612 
2613   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2614   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_COMBINED_GVDEFENTRY));
2615   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
2616   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // sumoffset
2617   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // guid
2618   unsigned DefEntryAbbrev = Stream.EmitAbbrev(Abbv);
2619 
2620   Abbv = new BitCodeAbbrev();
2621   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_COMBINED_ENTRY));
2622   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
2623   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // refguid
2624   unsigned EntryAbbrev = Stream.EmitAbbrev(Abbv);
2625 
2626   SmallVector<uint64_t, 64> NameVals;
2627 
2628   for (const auto &FII : Index) {
2629     GlobalValue::GUID FuncGUID = FII.first;
2630     unsigned ValueId = popValueId(FuncGUID);
2631 
2632     for (const auto &FI : FII.second) {
2633       // VST_CODE_COMBINED_GVDEFENTRY: [valueid, sumoffset, guid]
2634       NameVals.push_back(ValueId);
2635       NameVals.push_back(FI->bitcodeIndex());
2636       NameVals.push_back(FuncGUID);
2637 
2638       // Emit the finished record.
2639       Stream.EmitRecord(bitc::VST_CODE_COMBINED_GVDEFENTRY, NameVals,
2640                         DefEntryAbbrev);
2641       NameVals.clear();
2642     }
2643   }
2644   for (const auto &GVI : valueIds()) {
2645     // VST_CODE_COMBINED_ENTRY: [valueid, refguid]
2646     NameVals.push_back(GVI.second);
2647     NameVals.push_back(GVI.first);
2648 
2649     // Emit the finished record.
2650     Stream.EmitRecord(bitc::VST_CODE_COMBINED_ENTRY, NameVals, EntryAbbrev);
2651     NameVals.clear();
2652   }
2653   Stream.ExitBlock();
2654 }
2655 
2656 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
2657   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
2658   unsigned Code;
2659   if (isa<BasicBlock>(Order.V))
2660     Code = bitc::USELIST_CODE_BB;
2661   else
2662     Code = bitc::USELIST_CODE_DEFAULT;
2663 
2664   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
2665   Record.push_back(VE.getValueID(Order.V));
2666   Stream.EmitRecord(Code, Record);
2667 }
2668 
2669 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
2670   assert(VE.shouldPreserveUseListOrder() &&
2671          "Expected to be preserving use-list order");
2672 
2673   auto hasMore = [&]() {
2674     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
2675   };
2676   if (!hasMore())
2677     // Nothing to do.
2678     return;
2679 
2680   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
2681   while (hasMore()) {
2682     writeUseList(std::move(VE.UseListOrders.back()));
2683     VE.UseListOrders.pop_back();
2684   }
2685   Stream.ExitBlock();
2686 }
2687 
2688 /// Emit a function body to the module stream.
2689 void ModuleBitcodeWriter::writeFunction(
2690     const Function &F,
2691     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
2692   // Save the bitcode index of the start of this function block for recording
2693   // in the VST.
2694   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
2695 
2696   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
2697   VE.incorporateFunction(F);
2698 
2699   SmallVector<unsigned, 64> Vals;
2700 
2701   // Emit the number of basic blocks, so the reader can create them ahead of
2702   // time.
2703   Vals.push_back(VE.getBasicBlocks().size());
2704   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
2705   Vals.clear();
2706 
2707   // If there are function-local constants, emit them now.
2708   unsigned CstStart, CstEnd;
2709   VE.getFunctionConstantRange(CstStart, CstEnd);
2710   writeConstants(CstStart, CstEnd, false);
2711 
2712   // If there is function-local metadata, emit it now.
2713   writeFunctionMetadata(F);
2714 
2715   // Keep a running idea of what the instruction ID is.
2716   unsigned InstID = CstEnd;
2717 
2718   bool NeedsMetadataAttachment = F.hasMetadata();
2719 
2720   DILocation *LastDL = nullptr;
2721   // Finally, emit all the instructions, in order.
2722   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
2723     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
2724          I != E; ++I) {
2725       writeInstruction(*I, InstID, Vals);
2726 
2727       if (!I->getType()->isVoidTy())
2728         ++InstID;
2729 
2730       // If the instruction has metadata, write a metadata attachment later.
2731       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
2732 
2733       // If the instruction has a debug location, emit it.
2734       DILocation *DL = I->getDebugLoc();
2735       if (!DL)
2736         continue;
2737 
2738       if (DL == LastDL) {
2739         // Just repeat the same debug loc as last time.
2740         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
2741         continue;
2742       }
2743 
2744       Vals.push_back(DL->getLine());
2745       Vals.push_back(DL->getColumn());
2746       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
2747       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
2748       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
2749       Vals.clear();
2750 
2751       LastDL = DL;
2752     }
2753 
2754   // Emit names for all the instructions etc.
2755   writeValueSymbolTable(F.getValueSymbolTable());
2756 
2757   if (NeedsMetadataAttachment)
2758     writeMetadataAttachment(F);
2759   if (VE.shouldPreserveUseListOrder())
2760     writeUseListBlock(&F);
2761   VE.purgeFunction();
2762   Stream.ExitBlock();
2763 }
2764 
2765 // Emit blockinfo, which defines the standard abbreviations etc.
2766 void ModuleBitcodeWriter::writeBlockInfo() {
2767   // We only want to emit block info records for blocks that have multiple
2768   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
2769   // Other blocks can define their abbrevs inline.
2770   Stream.EnterBlockInfoBlock(2);
2771 
2772   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
2773     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2774     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
2775     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2776     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2777     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2778     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
2779         VST_ENTRY_8_ABBREV)
2780       llvm_unreachable("Unexpected abbrev ordering!");
2781   }
2782 
2783   { // 7-bit fixed width VST_CODE_ENTRY strings.
2784     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2785     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2786     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2787     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2788     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2789     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
2790         VST_ENTRY_7_ABBREV)
2791       llvm_unreachable("Unexpected abbrev ordering!");
2792   }
2793   { // 6-bit char6 VST_CODE_ENTRY strings.
2794     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2795     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2796     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2797     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2798     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2799     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
2800         VST_ENTRY_6_ABBREV)
2801       llvm_unreachable("Unexpected abbrev ordering!");
2802   }
2803   { // 6-bit char6 VST_CODE_BBENTRY strings.
2804     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2805     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
2806     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2807     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2808     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2809     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
2810         VST_BBENTRY_6_ABBREV)
2811       llvm_unreachable("Unexpected abbrev ordering!");
2812   }
2813 
2814 
2815 
2816   { // SETTYPE abbrev for CONSTANTS_BLOCK.
2817     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2818     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
2819     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
2820                               VE.computeBitsRequiredForTypeIndicies()));
2821     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
2822         CONSTANTS_SETTYPE_ABBREV)
2823       llvm_unreachable("Unexpected abbrev ordering!");
2824   }
2825 
2826   { // INTEGER abbrev for CONSTANTS_BLOCK.
2827     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2828     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
2829     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2830     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
2831         CONSTANTS_INTEGER_ABBREV)
2832       llvm_unreachable("Unexpected abbrev ordering!");
2833   }
2834 
2835   { // CE_CAST abbrev for CONSTANTS_BLOCK.
2836     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2837     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
2838     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
2839     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
2840                               VE.computeBitsRequiredForTypeIndicies()));
2841     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
2842 
2843     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
2844         CONSTANTS_CE_CAST_Abbrev)
2845       llvm_unreachable("Unexpected abbrev ordering!");
2846   }
2847   { // NULL abbrev for CONSTANTS_BLOCK.
2848     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2849     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
2850     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
2851         CONSTANTS_NULL_Abbrev)
2852       llvm_unreachable("Unexpected abbrev ordering!");
2853   }
2854 
2855   // FIXME: This should only use space for first class types!
2856 
2857   { // INST_LOAD abbrev for FUNCTION_BLOCK.
2858     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2859     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
2860     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
2861     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
2862                               VE.computeBitsRequiredForTypeIndicies()));
2863     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
2864     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
2865     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2866         FUNCTION_INST_LOAD_ABBREV)
2867       llvm_unreachable("Unexpected abbrev ordering!");
2868   }
2869   { // INST_BINOP abbrev for FUNCTION_BLOCK.
2870     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2871     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2872     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2873     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2874     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2875     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2876         FUNCTION_INST_BINOP_ABBREV)
2877       llvm_unreachable("Unexpected abbrev ordering!");
2878   }
2879   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
2880     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2881     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2882     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2883     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2884     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2885     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
2886     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2887         FUNCTION_INST_BINOP_FLAGS_ABBREV)
2888       llvm_unreachable("Unexpected abbrev ordering!");
2889   }
2890   { // INST_CAST abbrev for FUNCTION_BLOCK.
2891     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2892     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
2893     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
2894     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
2895                               VE.computeBitsRequiredForTypeIndicies()));
2896     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
2897     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2898         FUNCTION_INST_CAST_ABBREV)
2899       llvm_unreachable("Unexpected abbrev ordering!");
2900   }
2901 
2902   { // INST_RET abbrev for FUNCTION_BLOCK.
2903     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2904     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2905     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2906         FUNCTION_INST_RET_VOID_ABBREV)
2907       llvm_unreachable("Unexpected abbrev ordering!");
2908   }
2909   { // INST_RET abbrev for FUNCTION_BLOCK.
2910     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2911     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2912     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
2913     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2914         FUNCTION_INST_RET_VAL_ABBREV)
2915       llvm_unreachable("Unexpected abbrev ordering!");
2916   }
2917   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
2918     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2919     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
2920     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2921         FUNCTION_INST_UNREACHABLE_ABBREV)
2922       llvm_unreachable("Unexpected abbrev ordering!");
2923   }
2924   {
2925     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2926     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
2927     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2928     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
2929                               Log2_32_Ceil(VE.getTypes().size() + 1)));
2930     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2931     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2932     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2933         FUNCTION_INST_GEP_ABBREV)
2934       llvm_unreachable("Unexpected abbrev ordering!");
2935   }
2936 
2937   Stream.ExitBlock();
2938 }
2939 
2940 /// Write the module path strings, currently only used when generating
2941 /// a combined index file.
2942 void IndexBitcodeWriter::writeModStrings() {
2943   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
2944 
2945   // TODO: See which abbrev sizes we actually need to emit
2946 
2947   // 8-bit fixed-width MST_ENTRY strings.
2948   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2949   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
2950   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2951   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2952   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2953   unsigned Abbrev8Bit = Stream.EmitAbbrev(Abbv);
2954 
2955   // 7-bit fixed width MST_ENTRY strings.
2956   Abbv = new BitCodeAbbrev();
2957   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
2958   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2959   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2960   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2961   unsigned Abbrev7Bit = Stream.EmitAbbrev(Abbv);
2962 
2963   // 6-bit char6 MST_ENTRY strings.
2964   Abbv = new BitCodeAbbrev();
2965   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
2966   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2967   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2968   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2969   unsigned Abbrev6Bit = Stream.EmitAbbrev(Abbv);
2970 
2971   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
2972   Abbv = new BitCodeAbbrev();
2973   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
2974   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2975   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2976   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2977   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2978   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2979   unsigned AbbrevHash = Stream.EmitAbbrev(Abbv);
2980 
2981   SmallVector<unsigned, 64> Vals;
2982   for (const auto &MPSE : Index.modulePaths()) {
2983     StringEncoding Bits =
2984         getStringEncoding(MPSE.getKey().data(), MPSE.getKey().size());
2985     unsigned AbbrevToUse = Abbrev8Bit;
2986     if (Bits == SE_Char6)
2987       AbbrevToUse = Abbrev6Bit;
2988     else if (Bits == SE_Fixed7)
2989       AbbrevToUse = Abbrev7Bit;
2990 
2991     Vals.push_back(MPSE.getValue().first);
2992 
2993     for (const auto P : MPSE.getKey())
2994       Vals.push_back((unsigned char)P);
2995 
2996     // Emit the finished record.
2997     Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
2998 
2999     Vals.clear();
3000     // Emit an optional hash for the module now
3001     auto &Hash = MPSE.getValue().second;
3002     bool AllZero = true; // Detect if the hash is empty, and do not generate it
3003     for (auto Val : Hash) {
3004       if (Val)
3005         AllZero = false;
3006       Vals.push_back(Val);
3007     }
3008     if (!AllZero) {
3009       // Emit the hash record.
3010       Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3011     }
3012 
3013     Vals.clear();
3014   }
3015   Stream.ExitBlock();
3016 }
3017 
3018 // Helper to emit a single function summary record.
3019 void ModuleBitcodeWriter::writePerModuleFunctionSummaryRecord(
3020     SmallVector<uint64_t, 64> &NameVals, GlobalValueInfo *Info,
3021     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3022     const Function &F) {
3023   NameVals.push_back(ValueID);
3024 
3025   FunctionSummary *FS = cast<FunctionSummary>(Info->summary());
3026   NameVals.push_back(getEncodedLinkage(FS->linkage()));
3027   NameVals.push_back(FS->instCount());
3028   NameVals.push_back(FS->refs().size());
3029 
3030   for (auto &RI : FS->refs())
3031     NameVals.push_back(VE.getValueID(RI.getValue()));
3032 
3033   bool HasProfileData = F.getEntryCount().hasValue();
3034   for (auto &ECI : FS->calls()) {
3035     NameVals.push_back(VE.getValueID(ECI.first.getValue()));
3036     assert(ECI.second.CallsiteCount > 0 && "Expected at least one callsite");
3037     NameVals.push_back(ECI.second.CallsiteCount);
3038     if (HasProfileData)
3039       NameVals.push_back(ECI.second.ProfileCount);
3040   }
3041 
3042   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3043   unsigned Code =
3044       (HasProfileData ? bitc::FS_PERMODULE_PROFILE : bitc::FS_PERMODULE);
3045 
3046   // Emit the finished record.
3047   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3048   NameVals.clear();
3049 }
3050 
3051 // Collect the global value references in the given variable's initializer,
3052 // and emit them in a summary record.
3053 void ModuleBitcodeWriter::writeModuleLevelReferences(
3054     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3055     unsigned FSModRefsAbbrev) {
3056   // Only interested in recording variable defs in the summary.
3057   if (V.isDeclaration())
3058     return;
3059   NameVals.push_back(VE.getValueID(&V));
3060   NameVals.push_back(getEncodedLinkage(V.getLinkage()));
3061   auto *Info = Index->getGlobalValueInfo(V);
3062   GlobalVarSummary *VS = cast<GlobalVarSummary>(Info->summary());
3063   for (auto Ref : VS->refs())
3064     NameVals.push_back(VE.getValueID(Ref.getValue()));
3065   Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3066                     FSModRefsAbbrev);
3067   NameVals.clear();
3068 }
3069 
3070 /// Emit the per-module summary section alongside the rest of
3071 /// the module's bitcode.
3072 void ModuleBitcodeWriter::writePerModuleGlobalValueSummary() {
3073   if (M.empty())
3074     return;
3075 
3076   if (Index->begin() == Index->end())
3077     return;
3078 
3079   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
3080 
3081   // Abbrev for FS_PERMODULE.
3082   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3083   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
3084   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3085   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // linkage
3086   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3087   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3088   // numrefs x valueid, n x (valueid, callsitecount)
3089   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3090   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3091   unsigned FSCallsAbbrev = Stream.EmitAbbrev(Abbv);
3092 
3093   // Abbrev for FS_PERMODULE_PROFILE.
3094   Abbv = new BitCodeAbbrev();
3095   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
3096   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3097   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // linkage
3098   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3099   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3100   // numrefs x valueid, n x (valueid, callsitecount, profilecount)
3101   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3102   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3103   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(Abbv);
3104 
3105   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
3106   Abbv = new BitCodeAbbrev();
3107   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
3108   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3109   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // linkage
3110   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
3111   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3112   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(Abbv);
3113 
3114   // Abbrev for FS_ALIAS.
3115   Abbv = new BitCodeAbbrev();
3116   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
3117   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3118   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // linkage
3119   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3120   unsigned FSAliasAbbrev = Stream.EmitAbbrev(Abbv);
3121 
3122   SmallVector<uint64_t, 64> NameVals;
3123   // Iterate over the list of functions instead of the Index to
3124   // ensure the ordering is stable.
3125   for (const Function &F : M) {
3126     if (F.isDeclaration())
3127       continue;
3128     // Summary emission does not support anonymous functions, they have to
3129     // renamed using the anonymous function renaming pass.
3130     if (!F.hasName())
3131       report_fatal_error("Unexpected anonymous function when writing summary");
3132 
3133     auto *Info = Index->getGlobalValueInfo(F);
3134     writePerModuleFunctionSummaryRecord(
3135         NameVals, Info,
3136         VE.getValueID(M.getValueSymbolTable().lookup(F.getName())),
3137         FSCallsAbbrev, FSCallsProfileAbbrev, F);
3138   }
3139 
3140   // Capture references from GlobalVariable initializers, which are outside
3141   // of a function scope.
3142   for (const GlobalVariable &G : M.globals())
3143     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev);
3144 
3145   for (const GlobalAlias &A : M.aliases()) {
3146     auto *Aliasee = A.getBaseObject();
3147     if (!Aliasee->hasName())
3148       // Nameless function don't have an entry in the summary, skip it.
3149       continue;
3150     auto AliasId = VE.getValueID(&A);
3151     auto AliaseeId = VE.getValueID(Aliasee);
3152     NameVals.push_back(AliasId);
3153     NameVals.push_back(getEncodedLinkage(A.getLinkage()));
3154     NameVals.push_back(AliaseeId);
3155     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
3156     NameVals.clear();
3157   }
3158 
3159   Stream.ExitBlock();
3160 }
3161 
3162 /// Emit the combined summary section into the combined index file.
3163 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
3164   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
3165 
3166   // Abbrev for FS_COMBINED.
3167   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3168   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
3169   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3170   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // linkage
3171   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3172   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3173   // numrefs x valueid, n x (valueid, callsitecount)
3174   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3175   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3176   unsigned FSCallsAbbrev = Stream.EmitAbbrev(Abbv);
3177 
3178   // Abbrev for FS_COMBINED_PROFILE.
3179   Abbv = new BitCodeAbbrev();
3180   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
3181   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3182   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // linkage
3183   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3184   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3185   // numrefs x valueid, n x (valueid, callsitecount, profilecount)
3186   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3187   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3188   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(Abbv);
3189 
3190   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
3191   Abbv = new BitCodeAbbrev();
3192   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
3193   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3194   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // linkage
3195   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
3196   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3197   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(Abbv);
3198 
3199   // Abbrev for FS_COMBINED_ALIAS.
3200   Abbv = new BitCodeAbbrev();
3201   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
3202   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3203   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // linkage
3204   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // offset
3205   unsigned FSAliasAbbrev = Stream.EmitAbbrev(Abbv);
3206 
3207   // The aliases are emitted as a post-pass, and will point to the summary
3208   // offset id of the aliasee. For this purpose we need to be able to get back
3209   // from the summary to the offset
3210   SmallVector<GlobalValueInfo *, 64> Aliases;
3211   DenseMap<const GlobalValueSummary *, uint64_t> SummaryToOffsetMap;
3212 
3213   SmallVector<uint64_t, 64> NameVals;
3214   for (const auto &FII : Index) {
3215     for (auto &FI : FII.second) {
3216       GlobalValueSummary *S = FI->summary();
3217       assert(S);
3218       if (isa<AliasSummary>(S)) {
3219         // Will process aliases as a post-pass because the reader wants all
3220         // global to be loaded first.
3221         Aliases.push_back(FI.get());
3222         continue;
3223       }
3224 
3225       if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
3226         NameVals.push_back(Index.getModuleId(VS->modulePath()));
3227         NameVals.push_back(getEncodedLinkage(VS->linkage()));
3228         for (auto &RI : VS->refs()) {
3229           NameVals.push_back(getValueId(RI.getGUID()));
3230         }
3231 
3232         // Record the starting offset of this summary entry for use
3233         // in the VST entry. Add the current code size since the
3234         // reader will invoke readRecord after the abbrev id read.
3235         FI->setBitcodeIndex(Stream.GetCurrentBitNo() +
3236                             Stream.GetAbbrevIDWidth());
3237         // Store temporarily the offset in the map for a possible alias.
3238         SummaryToOffsetMap[S] = FI->bitcodeIndex();
3239 
3240         // Emit the finished record.
3241         Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
3242                           FSModRefsAbbrev);
3243         NameVals.clear();
3244         continue;
3245       }
3246 
3247       auto *FS = cast<FunctionSummary>(S);
3248       NameVals.push_back(Index.getModuleId(FS->modulePath()));
3249       NameVals.push_back(getEncodedLinkage(FS->linkage()));
3250       NameVals.push_back(FS->instCount());
3251       NameVals.push_back(FS->refs().size());
3252 
3253       for (auto &RI : FS->refs()) {
3254         NameVals.push_back(getValueId(RI.getGUID()));
3255       }
3256 
3257       bool HasProfileData = false;
3258       for (auto &EI : FS->calls()) {
3259         HasProfileData |= EI.second.ProfileCount != 0;
3260         if (HasProfileData)
3261           break;
3262       }
3263 
3264       for (auto &EI : FS->calls()) {
3265         // If this GUID doesn't have a value id, it doesn't have a function
3266         // summary and we don't need to record any calls to it.
3267         if (!hasValueId(EI.first.getGUID()))
3268           continue;
3269         NameVals.push_back(getValueId(EI.first.getGUID()));
3270         assert(EI.second.CallsiteCount > 0 && "Expected at least one callsite");
3271         NameVals.push_back(EI.second.CallsiteCount);
3272         if (HasProfileData)
3273           NameVals.push_back(EI.second.ProfileCount);
3274       }
3275 
3276       // Record the starting offset of this summary entry for use
3277       // in the VST entry. Add the current code size since the
3278       // reader will invoke readRecord after the abbrev id read.
3279       FI->setBitcodeIndex(Stream.GetCurrentBitNo() + Stream.GetAbbrevIDWidth());
3280       // Store temporarily the offset in the map for a possible alias.
3281       SummaryToOffsetMap[S] = FI->bitcodeIndex();
3282 
3283       unsigned FSAbbrev =
3284           (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3285       unsigned Code =
3286           (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
3287 
3288       // Emit the finished record.
3289       Stream.EmitRecord(Code, NameVals, FSAbbrev);
3290       NameVals.clear();
3291     }
3292   }
3293 
3294   for (auto GVI : Aliases) {
3295     AliasSummary *AS = cast<AliasSummary>(GVI->summary());
3296     NameVals.push_back(Index.getModuleId(AS->modulePath()));
3297     NameVals.push_back(getEncodedLinkage(AS->linkage()));
3298     auto AliaseeOffset = SummaryToOffsetMap[&AS->getAliasee()];
3299     assert(AliaseeOffset);
3300     NameVals.push_back(AliaseeOffset);
3301 
3302     // Record the starting offset of this summary entry for use
3303     // in the VST entry. Add the current code size since the
3304     // reader will invoke readRecord after the abbrev id read.
3305     GVI->setBitcodeIndex(Stream.GetCurrentBitNo() + Stream.GetAbbrevIDWidth());
3306 
3307     // Emit the finished record.
3308     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
3309     NameVals.clear();
3310   }
3311 
3312   Stream.ExitBlock();
3313 }
3314 
3315 void ModuleBitcodeWriter::writeIdentificationBlock() {
3316   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
3317 
3318   // Write the "user readable" string identifying the bitcode producer
3319   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3320   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
3321   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3322   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3323   auto StringAbbrev = Stream.EmitAbbrev(Abbv);
3324   writeStringRecord(bitc::IDENTIFICATION_CODE_STRING,
3325                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
3326 
3327   // Write the epoch version
3328   Abbv = new BitCodeAbbrev();
3329   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
3330   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3331   auto EpochAbbrev = Stream.EmitAbbrev(Abbv);
3332   SmallVector<unsigned, 1> Vals = {bitc::BITCODE_CURRENT_EPOCH};
3333   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
3334   Stream.ExitBlock();
3335 }
3336 
3337 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
3338   // Emit the module's hash.
3339   // MODULE_CODE_HASH: [5*i32]
3340   SHA1 Hasher;
3341   Hasher.update(ArrayRef<uint8_t>((uint8_t *)&(Buffer)[BlockStartPos],
3342                                   Buffer.size() - BlockStartPos));
3343   auto Hash = Hasher.result();
3344   SmallVector<uint64_t, 20> Vals;
3345   auto LShift = [&](unsigned char Val, unsigned Amount)
3346                     -> uint64_t { return ((uint64_t)Val) << Amount; };
3347   for (int Pos = 0; Pos < 20; Pos += 4) {
3348     uint32_t SubHash = LShift(Hash[Pos + 0], 24);
3349     SubHash |= LShift(Hash[Pos + 1], 16) | LShift(Hash[Pos + 2], 8) |
3350                (unsigned)(unsigned char)Hash[Pos + 3];
3351     Vals.push_back(SubHash);
3352   }
3353 
3354   // Emit the finished record.
3355   Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
3356 }
3357 
3358 void BitcodeWriter::write() {
3359   // Emit the file header first.
3360   writeBitcodeHeader();
3361 
3362   writeBlocks();
3363 }
3364 
3365 void ModuleBitcodeWriter::writeBlocks() {
3366   writeIdentificationBlock();
3367   writeModule();
3368 }
3369 
3370 void IndexBitcodeWriter::writeBlocks() {
3371   // Index contains only a single outer (module) block.
3372   writeIndex();
3373 }
3374 
3375 void ModuleBitcodeWriter::writeModule() {
3376   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
3377   size_t BlockStartPos = Buffer.size();
3378 
3379   SmallVector<unsigned, 1> Vals;
3380   unsigned CurVersion = 1;
3381   Vals.push_back(CurVersion);
3382   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
3383 
3384   // Emit blockinfo, which defines the standard abbreviations etc.
3385   writeBlockInfo();
3386 
3387   // Emit information about attribute groups.
3388   writeAttributeGroupTable();
3389 
3390   // Emit information about parameter attributes.
3391   writeAttributeTable();
3392 
3393   // Emit information describing all of the types in the module.
3394   writeTypeTable();
3395 
3396   writeComdats();
3397 
3398   // Emit top-level description of module, including target triple, inline asm,
3399   // descriptors for global variables, and function prototype info.
3400   writeModuleInfo();
3401 
3402   // Emit constants.
3403   writeModuleConstants();
3404 
3405   // Emit metadata.
3406   writeModuleMetadata();
3407 
3408   // Emit metadata.
3409   writeModuleMetadataStore();
3410 
3411   // Emit module-level use-lists.
3412   if (VE.shouldPreserveUseListOrder())
3413     writeUseListBlock(nullptr);
3414 
3415   writeOperandBundleTags();
3416 
3417   // Emit function bodies.
3418   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
3419   for (Module::const_iterator F = M.begin(), E = M.end(); F != E; ++F)
3420     if (!F->isDeclaration())
3421       writeFunction(*F, FunctionToBitcodeIndex);
3422 
3423   // Need to write after the above call to WriteFunction which populates
3424   // the summary information in the index.
3425   if (Index)
3426     writePerModuleGlobalValueSummary();
3427 
3428   writeValueSymbolTable(M.getValueSymbolTable(),
3429                         /* IsModuleLevel */ true, &FunctionToBitcodeIndex);
3430 
3431   if (GenerateHash) {
3432     writeModuleHash(BlockStartPos);
3433   }
3434 
3435   Stream.ExitBlock();
3436 }
3437 
3438 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
3439                                uint32_t &Position) {
3440   support::endian::write32le(&Buffer[Position], Value);
3441   Position += 4;
3442 }
3443 
3444 /// If generating a bc file on darwin, we have to emit a
3445 /// header and trailer to make it compatible with the system archiver.  To do
3446 /// this we emit the following header, and then emit a trailer that pads the
3447 /// file out to be a multiple of 16 bytes.
3448 ///
3449 /// struct bc_header {
3450 ///   uint32_t Magic;         // 0x0B17C0DE
3451 ///   uint32_t Version;       // Version, currently always 0.
3452 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
3453 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
3454 ///   uint32_t CPUType;       // CPU specifier.
3455 ///   ... potentially more later ...
3456 /// };
3457 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
3458                                          const Triple &TT) {
3459   unsigned CPUType = ~0U;
3460 
3461   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
3462   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
3463   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
3464   // specific constants here because they are implicitly part of the Darwin ABI.
3465   enum {
3466     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
3467     DARWIN_CPU_TYPE_X86        = 7,
3468     DARWIN_CPU_TYPE_ARM        = 12,
3469     DARWIN_CPU_TYPE_POWERPC    = 18
3470   };
3471 
3472   Triple::ArchType Arch = TT.getArch();
3473   if (Arch == Triple::x86_64)
3474     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
3475   else if (Arch == Triple::x86)
3476     CPUType = DARWIN_CPU_TYPE_X86;
3477   else if (Arch == Triple::ppc)
3478     CPUType = DARWIN_CPU_TYPE_POWERPC;
3479   else if (Arch == Triple::ppc64)
3480     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
3481   else if (Arch == Triple::arm || Arch == Triple::thumb)
3482     CPUType = DARWIN_CPU_TYPE_ARM;
3483 
3484   // Traditional Bitcode starts after header.
3485   assert(Buffer.size() >= BWH_HeaderSize &&
3486          "Expected header size to be reserved");
3487   unsigned BCOffset = BWH_HeaderSize;
3488   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
3489 
3490   // Write the magic and version.
3491   unsigned Position = 0;
3492   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
3493   writeInt32ToBuffer(0, Buffer, Position); // Version.
3494   writeInt32ToBuffer(BCOffset, Buffer, Position);
3495   writeInt32ToBuffer(BCSize, Buffer, Position);
3496   writeInt32ToBuffer(CPUType, Buffer, Position);
3497 
3498   // If the file is not a multiple of 16 bytes, insert dummy padding.
3499   while (Buffer.size() & 15)
3500     Buffer.push_back(0);
3501 }
3502 
3503 /// Helper to write the header common to all bitcode files.
3504 void BitcodeWriter::writeBitcodeHeader() {
3505   // Emit the file header.
3506   Stream.Emit((unsigned)'B', 8);
3507   Stream.Emit((unsigned)'C', 8);
3508   Stream.Emit(0x0, 4);
3509   Stream.Emit(0xC, 4);
3510   Stream.Emit(0xE, 4);
3511   Stream.Emit(0xD, 4);
3512 }
3513 
3514 /// WriteBitcodeToFile - Write the specified module to the specified output
3515 /// stream.
3516 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out,
3517                               bool ShouldPreserveUseListOrder,
3518                               const ModuleSummaryIndex *Index,
3519                               bool GenerateHash) {
3520   SmallVector<char, 0> Buffer;
3521   Buffer.reserve(256*1024);
3522 
3523   // If this is darwin or another generic macho target, reserve space for the
3524   // header.
3525   Triple TT(M->getTargetTriple());
3526   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
3527     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
3528 
3529   // Emit the module into the buffer.
3530   ModuleBitcodeWriter ModuleWriter(M, Buffer, ShouldPreserveUseListOrder, Index,
3531                                    GenerateHash);
3532   ModuleWriter.write();
3533 
3534   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
3535     emitDarwinBCHeaderAndTrailer(Buffer, TT);
3536 
3537   // Write the generated bitstream to "Out".
3538   Out.write((char*)&Buffer.front(), Buffer.size());
3539 }
3540 
3541 void IndexBitcodeWriter::writeIndex() {
3542   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
3543 
3544   SmallVector<unsigned, 1> Vals;
3545   unsigned CurVersion = 1;
3546   Vals.push_back(CurVersion);
3547   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
3548 
3549   // If we have a VST, write the VSTOFFSET record placeholder.
3550   writeValueSymbolTableForwardDecl();
3551 
3552   // Write the module paths in the combined index.
3553   writeModStrings();
3554 
3555   // Write the summary combined index records.
3556   writeCombinedGlobalValueSummary();
3557 
3558   // Need a special VST writer for the combined index (we don't have a
3559   // real VST and real values when this is invoked).
3560   writeCombinedValueSymbolTable();
3561 
3562   Stream.ExitBlock();
3563 }
3564 
3565 // Write the specified module summary index to the given raw output stream,
3566 // where it will be written in a new bitcode block. This is used when
3567 // writing the combined index file for ThinLTO.
3568 void llvm::WriteIndexToFile(const ModuleSummaryIndex &Index, raw_ostream &Out) {
3569   SmallVector<char, 0> Buffer;
3570   Buffer.reserve(256 * 1024);
3571 
3572   IndexBitcodeWriter IndexWriter(Buffer, Index);
3573   IndexWriter.write();
3574 
3575   Out.write((char *)&Buffer.front(), Buffer.size());
3576 }
3577