xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision c814e0c1fd51de39c46a8b6168a299dacc410f17)
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   Record.push_back(N->isDistinct());
1277   Record.push_back(N->getTag());
1278   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1279   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1280   Record.push_back(N->getLine());
1281   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1282   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1283   Record.push_back(N->getSizeInBits());
1284   Record.push_back(N->getAlignInBits());
1285   Record.push_back(N->getOffsetInBits());
1286   Record.push_back(N->getFlags());
1287   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1288   Record.push_back(N->getRuntimeLang());
1289   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1290   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1291   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1292 
1293   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1294   Record.clear();
1295 }
1296 
1297 void ModuleBitcodeWriter::writeDISubroutineType(
1298     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1299     unsigned Abbrev) {
1300   Record.push_back(N->isDistinct());
1301   Record.push_back(N->getFlags());
1302   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1303 
1304   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1305   Record.clear();
1306 }
1307 
1308 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1309                                       SmallVectorImpl<uint64_t> &Record,
1310                                       unsigned Abbrev) {
1311   Record.push_back(N->isDistinct());
1312   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1313   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1314 
1315   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1316   Record.clear();
1317 }
1318 
1319 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1320                                              SmallVectorImpl<uint64_t> &Record,
1321                                              unsigned Abbrev) {
1322   assert(N->isDistinct() && "Expected distinct compile units");
1323   Record.push_back(/* IsDistinct */ true);
1324   Record.push_back(N->getSourceLanguage());
1325   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1326   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1327   Record.push_back(N->isOptimized());
1328   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1329   Record.push_back(N->getRuntimeVersion());
1330   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1331   Record.push_back(N->getEmissionKind());
1332   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1333   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1334   Record.push_back(/* subprograms */ 0);
1335   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1336   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1337   Record.push_back(N->getDWOId());
1338   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1339 
1340   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1341   Record.clear();
1342 }
1343 
1344 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1345                                             SmallVectorImpl<uint64_t> &Record,
1346                                             unsigned Abbrev) {
1347   Record.push_back(N->isDistinct());
1348   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1349   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1350   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1351   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1352   Record.push_back(N->getLine());
1353   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1354   Record.push_back(N->isLocalToUnit());
1355   Record.push_back(N->isDefinition());
1356   Record.push_back(N->getScopeLine());
1357   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1358   Record.push_back(N->getVirtuality());
1359   Record.push_back(N->getVirtualIndex());
1360   Record.push_back(N->getFlags());
1361   Record.push_back(N->isOptimized());
1362   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1363   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1364   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1365   Record.push_back(VE.getMetadataOrNullID(N->getVariables().get()));
1366 
1367   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1368   Record.clear();
1369 }
1370 
1371 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1372                                               SmallVectorImpl<uint64_t> &Record,
1373                                               unsigned Abbrev) {
1374   Record.push_back(N->isDistinct());
1375   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1376   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1377   Record.push_back(N->getLine());
1378   Record.push_back(N->getColumn());
1379 
1380   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1381   Record.clear();
1382 }
1383 
1384 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1385     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1386     unsigned Abbrev) {
1387   Record.push_back(N->isDistinct());
1388   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1389   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1390   Record.push_back(N->getDiscriminator());
1391 
1392   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1393   Record.clear();
1394 }
1395 
1396 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1397                                            SmallVectorImpl<uint64_t> &Record,
1398                                            unsigned Abbrev) {
1399   Record.push_back(N->isDistinct());
1400   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1401   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1402   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1403   Record.push_back(N->getLine());
1404 
1405   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1406   Record.clear();
1407 }
1408 
1409 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1410                                        SmallVectorImpl<uint64_t> &Record,
1411                                        unsigned Abbrev) {
1412   Record.push_back(N->isDistinct());
1413   Record.push_back(N->getMacinfoType());
1414   Record.push_back(N->getLine());
1415   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1416   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1417 
1418   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1419   Record.clear();
1420 }
1421 
1422 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1423                                            SmallVectorImpl<uint64_t> &Record,
1424                                            unsigned Abbrev) {
1425   Record.push_back(N->isDistinct());
1426   Record.push_back(N->getMacinfoType());
1427   Record.push_back(N->getLine());
1428   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1429   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1430 
1431   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1432   Record.clear();
1433 }
1434 
1435 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1436                                         SmallVectorImpl<uint64_t> &Record,
1437                                         unsigned Abbrev) {
1438   Record.push_back(N->isDistinct());
1439   for (auto &I : N->operands())
1440     Record.push_back(VE.getMetadataOrNullID(I));
1441 
1442   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1443   Record.clear();
1444 }
1445 
1446 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1447     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1448     unsigned Abbrev) {
1449   Record.push_back(N->isDistinct());
1450   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1451   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1452 
1453   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1454   Record.clear();
1455 }
1456 
1457 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1458     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1459     unsigned Abbrev) {
1460   Record.push_back(N->isDistinct());
1461   Record.push_back(N->getTag());
1462   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1463   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1464   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1465 
1466   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1467   Record.clear();
1468 }
1469 
1470 void ModuleBitcodeWriter::writeDIGlobalVariable(
1471     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1472     unsigned Abbrev) {
1473   Record.push_back(N->isDistinct());
1474   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1475   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1476   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1477   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1478   Record.push_back(N->getLine());
1479   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1480   Record.push_back(N->isLocalToUnit());
1481   Record.push_back(N->isDefinition());
1482   Record.push_back(VE.getMetadataOrNullID(N->getRawVariable()));
1483   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1484 
1485   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1486   Record.clear();
1487 }
1488 
1489 void ModuleBitcodeWriter::writeDILocalVariable(
1490     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
1491     unsigned Abbrev) {
1492   Record.push_back(N->isDistinct());
1493   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1494   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1495   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1496   Record.push_back(N->getLine());
1497   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1498   Record.push_back(N->getArg());
1499   Record.push_back(N->getFlags());
1500 
1501   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1502   Record.clear();
1503 }
1504 
1505 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
1506                                             SmallVectorImpl<uint64_t> &Record,
1507                                             unsigned Abbrev) {
1508   Record.reserve(N->getElements().size() + 1);
1509 
1510   Record.push_back(N->isDistinct());
1511   Record.append(N->elements_begin(), N->elements_end());
1512 
1513   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
1514   Record.clear();
1515 }
1516 
1517 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
1518                                               SmallVectorImpl<uint64_t> &Record,
1519                                               unsigned Abbrev) {
1520   Record.push_back(N->isDistinct());
1521   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1522   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1523   Record.push_back(N->getLine());
1524   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
1525   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
1526   Record.push_back(N->getAttributes());
1527   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1528 
1529   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
1530   Record.clear();
1531 }
1532 
1533 void ModuleBitcodeWriter::writeDIImportedEntity(
1534     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
1535     unsigned Abbrev) {
1536   Record.push_back(N->isDistinct());
1537   Record.push_back(N->getTag());
1538   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1539   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
1540   Record.push_back(N->getLine());
1541   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1542 
1543   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
1544   Record.clear();
1545 }
1546 
1547 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
1548   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1549   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
1550   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1551   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1552   return Stream.EmitAbbrev(Abbv);
1553 }
1554 
1555 void ModuleBitcodeWriter::writeNamedMetadata(
1556     SmallVectorImpl<uint64_t> &Record) {
1557   if (M.named_metadata_empty())
1558     return;
1559 
1560   unsigned Abbrev = createNamedMetadataAbbrev();
1561   for (const NamedMDNode &NMD : M.named_metadata()) {
1562     // Write name.
1563     StringRef Str = NMD.getName();
1564     Record.append(Str.bytes_begin(), Str.bytes_end());
1565     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
1566     Record.clear();
1567 
1568     // Write named metadata operands.
1569     for (const MDNode *N : NMD.operands())
1570       Record.push_back(VE.getMetadataID(N));
1571     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
1572     Record.clear();
1573   }
1574 }
1575 
1576 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
1577   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1578   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
1579   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
1580   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
1581   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
1582   return Stream.EmitAbbrev(Abbv);
1583 }
1584 
1585 /// Write out a record for MDString.
1586 ///
1587 /// All the metadata strings in a metadata block are emitted in a single
1588 /// record.  The sizes and strings themselves are shoved into a blob.
1589 void ModuleBitcodeWriter::writeMetadataStrings(
1590     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
1591   if (Strings.empty())
1592     return;
1593 
1594   // Start the record with the number of strings.
1595   Record.push_back(bitc::METADATA_STRINGS);
1596   Record.push_back(Strings.size());
1597 
1598   // Emit the sizes of the strings in the blob.
1599   SmallString<256> Blob;
1600   {
1601     BitstreamWriter W(Blob);
1602     for (const Metadata *MD : Strings)
1603       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
1604     W.FlushToWord();
1605   }
1606 
1607   // Add the offset to the strings to the record.
1608   Record.push_back(Blob.size());
1609 
1610   // Add the strings to the blob.
1611   for (const Metadata *MD : Strings)
1612     Blob.append(cast<MDString>(MD)->getString());
1613 
1614   // Emit the final record.
1615   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
1616   Record.clear();
1617 }
1618 
1619 void ModuleBitcodeWriter::writeMetadataRecords(
1620     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record) {
1621   if (MDs.empty())
1622     return;
1623 
1624   // Initialize MDNode abbreviations.
1625 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
1626 #include "llvm/IR/Metadata.def"
1627 
1628   for (const Metadata *MD : MDs) {
1629     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
1630       assert(N->isResolved() && "Expected forward references to be resolved");
1631 
1632       switch (N->getMetadataID()) {
1633       default:
1634         llvm_unreachable("Invalid MDNode subclass");
1635 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
1636   case Metadata::CLASS##Kind:                                                  \
1637     write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                       \
1638     continue;
1639 #include "llvm/IR/Metadata.def"
1640       }
1641     }
1642     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
1643   }
1644 }
1645 
1646 void ModuleBitcodeWriter::writeModuleMetadata() {
1647   if (!VE.hasMDs() && M.named_metadata_empty())
1648     return;
1649 
1650   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1651   SmallVector<uint64_t, 64> Record;
1652   writeMetadataStrings(VE.getMDStrings(), Record);
1653   writeMetadataRecords(VE.getNonMDStrings(), Record);
1654   writeNamedMetadata(Record);
1655   Stream.ExitBlock();
1656 }
1657 
1658 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
1659   if (!VE.hasMDs())
1660     return;
1661 
1662   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1663   SmallVector<uint64_t, 64> Record;
1664   writeMetadataStrings(VE.getMDStrings(), Record);
1665   writeMetadataRecords(VE.getNonMDStrings(), Record);
1666   Stream.ExitBlock();
1667 }
1668 
1669 void ModuleBitcodeWriter::writeMetadataAttachment(const Function &F) {
1670   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
1671 
1672   SmallVector<uint64_t, 64> Record;
1673 
1674   // Write metadata attachments
1675   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
1676   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
1677   F.getAllMetadata(MDs);
1678   if (!MDs.empty()) {
1679     for (const auto &I : MDs) {
1680       Record.push_back(I.first);
1681       Record.push_back(VE.getMetadataID(I.second));
1682     }
1683     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1684     Record.clear();
1685   }
1686 
1687   for (const BasicBlock &BB : F)
1688     for (const Instruction &I : BB) {
1689       MDs.clear();
1690       I.getAllMetadataOtherThanDebugLoc(MDs);
1691 
1692       // If no metadata, ignore instruction.
1693       if (MDs.empty()) continue;
1694 
1695       Record.push_back(VE.getInstructionID(&I));
1696 
1697       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1698         Record.push_back(MDs[i].first);
1699         Record.push_back(VE.getMetadataID(MDs[i].second));
1700       }
1701       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1702       Record.clear();
1703     }
1704 
1705   Stream.ExitBlock();
1706 }
1707 
1708 void ModuleBitcodeWriter::writeModuleMetadataStore() {
1709   SmallVector<uint64_t, 64> Record;
1710 
1711   // Write metadata kinds
1712   // METADATA_KIND - [n x [id, name]]
1713   SmallVector<StringRef, 8> Names;
1714   M.getMDKindNames(Names);
1715 
1716   if (Names.empty()) return;
1717 
1718   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
1719 
1720   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
1721     Record.push_back(MDKindID);
1722     StringRef KName = Names[MDKindID];
1723     Record.append(KName.begin(), KName.end());
1724 
1725     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
1726     Record.clear();
1727   }
1728 
1729   Stream.ExitBlock();
1730 }
1731 
1732 void ModuleBitcodeWriter::writeOperandBundleTags() {
1733   // Write metadata kinds
1734   //
1735   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
1736   //
1737   // OPERAND_BUNDLE_TAG - [strchr x N]
1738 
1739   SmallVector<StringRef, 8> Tags;
1740   M.getOperandBundleTags(Tags);
1741 
1742   if (Tags.empty())
1743     return;
1744 
1745   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
1746 
1747   SmallVector<uint64_t, 64> Record;
1748 
1749   for (auto Tag : Tags) {
1750     Record.append(Tag.begin(), Tag.end());
1751 
1752     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
1753     Record.clear();
1754   }
1755 
1756   Stream.ExitBlock();
1757 }
1758 
1759 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1760   if ((int64_t)V >= 0)
1761     Vals.push_back(V << 1);
1762   else
1763     Vals.push_back((-V << 1) | 1);
1764 }
1765 
1766 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
1767                                          bool isGlobal) {
1768   if (FirstVal == LastVal) return;
1769 
1770   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
1771 
1772   unsigned AggregateAbbrev = 0;
1773   unsigned String8Abbrev = 0;
1774   unsigned CString7Abbrev = 0;
1775   unsigned CString6Abbrev = 0;
1776   // If this is a constant pool for the module, emit module-specific abbrevs.
1777   if (isGlobal) {
1778     // Abbrev for CST_CODE_AGGREGATE.
1779     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1780     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
1781     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1782     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
1783     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
1784 
1785     // Abbrev for CST_CODE_STRING.
1786     Abbv = new BitCodeAbbrev();
1787     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
1788     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1789     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1790     String8Abbrev = Stream.EmitAbbrev(Abbv);
1791     // Abbrev for CST_CODE_CSTRING.
1792     Abbv = new BitCodeAbbrev();
1793     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1794     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1795     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1796     CString7Abbrev = Stream.EmitAbbrev(Abbv);
1797     // Abbrev for CST_CODE_CSTRING.
1798     Abbv = new BitCodeAbbrev();
1799     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1800     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1801     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1802     CString6Abbrev = Stream.EmitAbbrev(Abbv);
1803   }
1804 
1805   SmallVector<uint64_t, 64> Record;
1806 
1807   const ValueEnumerator::ValueList &Vals = VE.getValues();
1808   Type *LastTy = nullptr;
1809   for (unsigned i = FirstVal; i != LastVal; ++i) {
1810     const Value *V = Vals[i].first;
1811     // If we need to switch types, do so now.
1812     if (V->getType() != LastTy) {
1813       LastTy = V->getType();
1814       Record.push_back(VE.getTypeID(LastTy));
1815       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
1816                         CONSTANTS_SETTYPE_ABBREV);
1817       Record.clear();
1818     }
1819 
1820     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
1821       Record.push_back(unsigned(IA->hasSideEffects()) |
1822                        unsigned(IA->isAlignStack()) << 1 |
1823                        unsigned(IA->getDialect()&1) << 2);
1824 
1825       // Add the asm string.
1826       const std::string &AsmStr = IA->getAsmString();
1827       Record.push_back(AsmStr.size());
1828       Record.append(AsmStr.begin(), AsmStr.end());
1829 
1830       // Add the constraint string.
1831       const std::string &ConstraintStr = IA->getConstraintString();
1832       Record.push_back(ConstraintStr.size());
1833       Record.append(ConstraintStr.begin(), ConstraintStr.end());
1834       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
1835       Record.clear();
1836       continue;
1837     }
1838     const Constant *C = cast<Constant>(V);
1839     unsigned Code = -1U;
1840     unsigned AbbrevToUse = 0;
1841     if (C->isNullValue()) {
1842       Code = bitc::CST_CODE_NULL;
1843     } else if (isa<UndefValue>(C)) {
1844       Code = bitc::CST_CODE_UNDEF;
1845     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
1846       if (IV->getBitWidth() <= 64) {
1847         uint64_t V = IV->getSExtValue();
1848         emitSignedInt64(Record, V);
1849         Code = bitc::CST_CODE_INTEGER;
1850         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
1851       } else {                             // Wide integers, > 64 bits in size.
1852         // We have an arbitrary precision integer value to write whose
1853         // bit width is > 64. However, in canonical unsigned integer
1854         // format it is likely that the high bits are going to be zero.
1855         // So, we only write the number of active words.
1856         unsigned NWords = IV->getValue().getActiveWords();
1857         const uint64_t *RawWords = IV->getValue().getRawData();
1858         for (unsigned i = 0; i != NWords; ++i) {
1859           emitSignedInt64(Record, RawWords[i]);
1860         }
1861         Code = bitc::CST_CODE_WIDE_INTEGER;
1862       }
1863     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
1864       Code = bitc::CST_CODE_FLOAT;
1865       Type *Ty = CFP->getType();
1866       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
1867         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
1868       } else if (Ty->isX86_FP80Ty()) {
1869         // api needed to prevent premature destruction
1870         // bits are not in the same order as a normal i80 APInt, compensate.
1871         APInt api = CFP->getValueAPF().bitcastToAPInt();
1872         const uint64_t *p = api.getRawData();
1873         Record.push_back((p[1] << 48) | (p[0] >> 16));
1874         Record.push_back(p[0] & 0xffffLL);
1875       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
1876         APInt api = CFP->getValueAPF().bitcastToAPInt();
1877         const uint64_t *p = api.getRawData();
1878         Record.push_back(p[0]);
1879         Record.push_back(p[1]);
1880       } else {
1881         assert (0 && "Unknown FP type!");
1882       }
1883     } else if (isa<ConstantDataSequential>(C) &&
1884                cast<ConstantDataSequential>(C)->isString()) {
1885       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
1886       // Emit constant strings specially.
1887       unsigned NumElts = Str->getNumElements();
1888       // If this is a null-terminated string, use the denser CSTRING encoding.
1889       if (Str->isCString()) {
1890         Code = bitc::CST_CODE_CSTRING;
1891         --NumElts;  // Don't encode the null, which isn't allowed by char6.
1892       } else {
1893         Code = bitc::CST_CODE_STRING;
1894         AbbrevToUse = String8Abbrev;
1895       }
1896       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
1897       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
1898       for (unsigned i = 0; i != NumElts; ++i) {
1899         unsigned char V = Str->getElementAsInteger(i);
1900         Record.push_back(V);
1901         isCStr7 &= (V & 128) == 0;
1902         if (isCStrChar6)
1903           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
1904       }
1905 
1906       if (isCStrChar6)
1907         AbbrevToUse = CString6Abbrev;
1908       else if (isCStr7)
1909         AbbrevToUse = CString7Abbrev;
1910     } else if (const ConstantDataSequential *CDS =
1911                   dyn_cast<ConstantDataSequential>(C)) {
1912       Code = bitc::CST_CODE_DATA;
1913       Type *EltTy = CDS->getType()->getElementType();
1914       if (isa<IntegerType>(EltTy)) {
1915         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
1916           Record.push_back(CDS->getElementAsInteger(i));
1917       } else {
1918         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
1919           Record.push_back(
1920               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
1921       }
1922     } else if (isa<ConstantAggregate>(C)) {
1923       Code = bitc::CST_CODE_AGGREGATE;
1924       for (const Value *Op : C->operands())
1925         Record.push_back(VE.getValueID(Op));
1926       AbbrevToUse = AggregateAbbrev;
1927     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
1928       switch (CE->getOpcode()) {
1929       default:
1930         if (Instruction::isCast(CE->getOpcode())) {
1931           Code = bitc::CST_CODE_CE_CAST;
1932           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
1933           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1934           Record.push_back(VE.getValueID(C->getOperand(0)));
1935           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
1936         } else {
1937           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
1938           Code = bitc::CST_CODE_CE_BINOP;
1939           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
1940           Record.push_back(VE.getValueID(C->getOperand(0)));
1941           Record.push_back(VE.getValueID(C->getOperand(1)));
1942           uint64_t Flags = getOptimizationFlags(CE);
1943           if (Flags != 0)
1944             Record.push_back(Flags);
1945         }
1946         break;
1947       case Instruction::GetElementPtr: {
1948         Code = bitc::CST_CODE_CE_GEP;
1949         const auto *GO = cast<GEPOperator>(C);
1950         if (GO->isInBounds())
1951           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
1952         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
1953         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
1954           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
1955           Record.push_back(VE.getValueID(C->getOperand(i)));
1956         }
1957         break;
1958       }
1959       case Instruction::Select:
1960         Code = bitc::CST_CODE_CE_SELECT;
1961         Record.push_back(VE.getValueID(C->getOperand(0)));
1962         Record.push_back(VE.getValueID(C->getOperand(1)));
1963         Record.push_back(VE.getValueID(C->getOperand(2)));
1964         break;
1965       case Instruction::ExtractElement:
1966         Code = bitc::CST_CODE_CE_EXTRACTELT;
1967         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1968         Record.push_back(VE.getValueID(C->getOperand(0)));
1969         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
1970         Record.push_back(VE.getValueID(C->getOperand(1)));
1971         break;
1972       case Instruction::InsertElement:
1973         Code = bitc::CST_CODE_CE_INSERTELT;
1974         Record.push_back(VE.getValueID(C->getOperand(0)));
1975         Record.push_back(VE.getValueID(C->getOperand(1)));
1976         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
1977         Record.push_back(VE.getValueID(C->getOperand(2)));
1978         break;
1979       case Instruction::ShuffleVector:
1980         // If the return type and argument types are the same, this is a
1981         // standard shufflevector instruction.  If the types are different,
1982         // then the shuffle is widening or truncating the input vectors, and
1983         // the argument type must also be encoded.
1984         if (C->getType() == C->getOperand(0)->getType()) {
1985           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
1986         } else {
1987           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
1988           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1989         }
1990         Record.push_back(VE.getValueID(C->getOperand(0)));
1991         Record.push_back(VE.getValueID(C->getOperand(1)));
1992         Record.push_back(VE.getValueID(C->getOperand(2)));
1993         break;
1994       case Instruction::ICmp:
1995       case Instruction::FCmp:
1996         Code = bitc::CST_CODE_CE_CMP;
1997         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1998         Record.push_back(VE.getValueID(C->getOperand(0)));
1999         Record.push_back(VE.getValueID(C->getOperand(1)));
2000         Record.push_back(CE->getPredicate());
2001         break;
2002       }
2003     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2004       Code = bitc::CST_CODE_BLOCKADDRESS;
2005       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2006       Record.push_back(VE.getValueID(BA->getFunction()));
2007       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2008     } else {
2009 #ifndef NDEBUG
2010       C->dump();
2011 #endif
2012       llvm_unreachable("Unknown constant!");
2013     }
2014     Stream.EmitRecord(Code, Record, AbbrevToUse);
2015     Record.clear();
2016   }
2017 
2018   Stream.ExitBlock();
2019 }
2020 
2021 void ModuleBitcodeWriter::writeModuleConstants() {
2022   const ValueEnumerator::ValueList &Vals = VE.getValues();
2023 
2024   // Find the first constant to emit, which is the first non-globalvalue value.
2025   // We know globalvalues have been emitted by WriteModuleInfo.
2026   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2027     if (!isa<GlobalValue>(Vals[i].first)) {
2028       writeConstants(i, Vals.size(), true);
2029       return;
2030     }
2031   }
2032 }
2033 
2034 /// pushValueAndType - The file has to encode both the value and type id for
2035 /// many values, because we need to know what type to create for forward
2036 /// references.  However, most operands are not forward references, so this type
2037 /// field is not needed.
2038 ///
2039 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2040 /// instruction ID, then it is a forward reference, and it also includes the
2041 /// type ID.  The value ID that is written is encoded relative to the InstID.
2042 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2043                                            SmallVectorImpl<unsigned> &Vals) {
2044   unsigned ValID = VE.getValueID(V);
2045   // Make encoding relative to the InstID.
2046   Vals.push_back(InstID - ValID);
2047   if (ValID >= InstID) {
2048     Vals.push_back(VE.getTypeID(V->getType()));
2049     return true;
2050   }
2051   return false;
2052 }
2053 
2054 void ModuleBitcodeWriter::writeOperandBundles(ImmutableCallSite CS,
2055                                               unsigned InstID) {
2056   SmallVector<unsigned, 64> Record;
2057   LLVMContext &C = CS.getInstruction()->getContext();
2058 
2059   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2060     const auto &Bundle = CS.getOperandBundleAt(i);
2061     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2062 
2063     for (auto &Input : Bundle.Inputs)
2064       pushValueAndType(Input, InstID, Record);
2065 
2066     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2067     Record.clear();
2068   }
2069 }
2070 
2071 /// pushValue - Like pushValueAndType, but where the type of the value is
2072 /// omitted (perhaps it was already encoded in an earlier operand).
2073 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2074                                     SmallVectorImpl<unsigned> &Vals) {
2075   unsigned ValID = VE.getValueID(V);
2076   Vals.push_back(InstID - ValID);
2077 }
2078 
2079 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2080                                           SmallVectorImpl<uint64_t> &Vals) {
2081   unsigned ValID = VE.getValueID(V);
2082   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2083   emitSignedInt64(Vals, diff);
2084 }
2085 
2086 /// WriteInstruction - Emit an instruction to the specified stream.
2087 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2088                                            unsigned InstID,
2089                                            SmallVectorImpl<unsigned> &Vals) {
2090   unsigned Code = 0;
2091   unsigned AbbrevToUse = 0;
2092   VE.setInstructionID(&I);
2093   switch (I.getOpcode()) {
2094   default:
2095     if (Instruction::isCast(I.getOpcode())) {
2096       Code = bitc::FUNC_CODE_INST_CAST;
2097       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2098         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2099       Vals.push_back(VE.getTypeID(I.getType()));
2100       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2101     } else {
2102       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2103       Code = bitc::FUNC_CODE_INST_BINOP;
2104       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2105         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2106       pushValue(I.getOperand(1), InstID, Vals);
2107       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2108       uint64_t Flags = getOptimizationFlags(&I);
2109       if (Flags != 0) {
2110         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2111           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2112         Vals.push_back(Flags);
2113       }
2114     }
2115     break;
2116 
2117   case Instruction::GetElementPtr: {
2118     Code = bitc::FUNC_CODE_INST_GEP;
2119     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2120     auto &GEPInst = cast<GetElementPtrInst>(I);
2121     Vals.push_back(GEPInst.isInBounds());
2122     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2123     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2124       pushValueAndType(I.getOperand(i), InstID, Vals);
2125     break;
2126   }
2127   case Instruction::ExtractValue: {
2128     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2129     pushValueAndType(I.getOperand(0), InstID, Vals);
2130     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2131     Vals.append(EVI->idx_begin(), EVI->idx_end());
2132     break;
2133   }
2134   case Instruction::InsertValue: {
2135     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2136     pushValueAndType(I.getOperand(0), InstID, Vals);
2137     pushValueAndType(I.getOperand(1), InstID, Vals);
2138     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2139     Vals.append(IVI->idx_begin(), IVI->idx_end());
2140     break;
2141   }
2142   case Instruction::Select:
2143     Code = bitc::FUNC_CODE_INST_VSELECT;
2144     pushValueAndType(I.getOperand(1), InstID, Vals);
2145     pushValue(I.getOperand(2), InstID, Vals);
2146     pushValueAndType(I.getOperand(0), InstID, Vals);
2147     break;
2148   case Instruction::ExtractElement:
2149     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2150     pushValueAndType(I.getOperand(0), InstID, Vals);
2151     pushValueAndType(I.getOperand(1), InstID, Vals);
2152     break;
2153   case Instruction::InsertElement:
2154     Code = bitc::FUNC_CODE_INST_INSERTELT;
2155     pushValueAndType(I.getOperand(0), InstID, Vals);
2156     pushValue(I.getOperand(1), InstID, Vals);
2157     pushValueAndType(I.getOperand(2), InstID, Vals);
2158     break;
2159   case Instruction::ShuffleVector:
2160     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2161     pushValueAndType(I.getOperand(0), InstID, Vals);
2162     pushValue(I.getOperand(1), InstID, Vals);
2163     pushValue(I.getOperand(2), InstID, Vals);
2164     break;
2165   case Instruction::ICmp:
2166   case Instruction::FCmp: {
2167     // compare returning Int1Ty or vector of Int1Ty
2168     Code = bitc::FUNC_CODE_INST_CMP2;
2169     pushValueAndType(I.getOperand(0), InstID, Vals);
2170     pushValue(I.getOperand(1), InstID, Vals);
2171     Vals.push_back(cast<CmpInst>(I).getPredicate());
2172     uint64_t Flags = getOptimizationFlags(&I);
2173     if (Flags != 0)
2174       Vals.push_back(Flags);
2175     break;
2176   }
2177 
2178   case Instruction::Ret:
2179     {
2180       Code = bitc::FUNC_CODE_INST_RET;
2181       unsigned NumOperands = I.getNumOperands();
2182       if (NumOperands == 0)
2183         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2184       else if (NumOperands == 1) {
2185         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2186           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2187       } else {
2188         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2189           pushValueAndType(I.getOperand(i), InstID, Vals);
2190       }
2191     }
2192     break;
2193   case Instruction::Br:
2194     {
2195       Code = bitc::FUNC_CODE_INST_BR;
2196       const BranchInst &II = cast<BranchInst>(I);
2197       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2198       if (II.isConditional()) {
2199         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2200         pushValue(II.getCondition(), InstID, Vals);
2201       }
2202     }
2203     break;
2204   case Instruction::Switch:
2205     {
2206       Code = bitc::FUNC_CODE_INST_SWITCH;
2207       const SwitchInst &SI = cast<SwitchInst>(I);
2208       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2209       pushValue(SI.getCondition(), InstID, Vals);
2210       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2211       for (SwitchInst::ConstCaseIt Case : SI.cases()) {
2212         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2213         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2214       }
2215     }
2216     break;
2217   case Instruction::IndirectBr:
2218     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2219     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2220     // Encode the address operand as relative, but not the basic blocks.
2221     pushValue(I.getOperand(0), InstID, Vals);
2222     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2223       Vals.push_back(VE.getValueID(I.getOperand(i)));
2224     break;
2225 
2226   case Instruction::Invoke: {
2227     const InvokeInst *II = cast<InvokeInst>(&I);
2228     const Value *Callee = II->getCalledValue();
2229     FunctionType *FTy = II->getFunctionType();
2230 
2231     if (II->hasOperandBundles())
2232       writeOperandBundles(II, InstID);
2233 
2234     Code = bitc::FUNC_CODE_INST_INVOKE;
2235 
2236     Vals.push_back(VE.getAttributeID(II->getAttributes()));
2237     Vals.push_back(II->getCallingConv() | 1 << 13);
2238     Vals.push_back(VE.getValueID(II->getNormalDest()));
2239     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2240     Vals.push_back(VE.getTypeID(FTy));
2241     pushValueAndType(Callee, InstID, Vals);
2242 
2243     // Emit value #'s for the fixed parameters.
2244     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2245       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2246 
2247     // Emit type/value pairs for varargs params.
2248     if (FTy->isVarArg()) {
2249       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
2250            i != e; ++i)
2251         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2252     }
2253     break;
2254   }
2255   case Instruction::Resume:
2256     Code = bitc::FUNC_CODE_INST_RESUME;
2257     pushValueAndType(I.getOperand(0), InstID, Vals);
2258     break;
2259   case Instruction::CleanupRet: {
2260     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2261     const auto &CRI = cast<CleanupReturnInst>(I);
2262     pushValue(CRI.getCleanupPad(), InstID, Vals);
2263     if (CRI.hasUnwindDest())
2264       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2265     break;
2266   }
2267   case Instruction::CatchRet: {
2268     Code = bitc::FUNC_CODE_INST_CATCHRET;
2269     const auto &CRI = cast<CatchReturnInst>(I);
2270     pushValue(CRI.getCatchPad(), InstID, Vals);
2271     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2272     break;
2273   }
2274   case Instruction::CleanupPad:
2275   case Instruction::CatchPad: {
2276     const auto &FuncletPad = cast<FuncletPadInst>(I);
2277     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2278                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2279     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2280 
2281     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2282     Vals.push_back(NumArgOperands);
2283     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2284       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2285     break;
2286   }
2287   case Instruction::CatchSwitch: {
2288     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2289     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2290 
2291     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2292 
2293     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2294     Vals.push_back(NumHandlers);
2295     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2296       Vals.push_back(VE.getValueID(CatchPadBB));
2297 
2298     if (CatchSwitch.hasUnwindDest())
2299       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
2300     break;
2301   }
2302   case Instruction::Unreachable:
2303     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
2304     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
2305     break;
2306 
2307   case Instruction::PHI: {
2308     const PHINode &PN = cast<PHINode>(I);
2309     Code = bitc::FUNC_CODE_INST_PHI;
2310     // With the newer instruction encoding, forward references could give
2311     // negative valued IDs.  This is most common for PHIs, so we use
2312     // signed VBRs.
2313     SmallVector<uint64_t, 128> Vals64;
2314     Vals64.push_back(VE.getTypeID(PN.getType()));
2315     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
2316       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
2317       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
2318     }
2319     // Emit a Vals64 vector and exit.
2320     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
2321     Vals64.clear();
2322     return;
2323   }
2324 
2325   case Instruction::LandingPad: {
2326     const LandingPadInst &LP = cast<LandingPadInst>(I);
2327     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
2328     Vals.push_back(VE.getTypeID(LP.getType()));
2329     Vals.push_back(LP.isCleanup());
2330     Vals.push_back(LP.getNumClauses());
2331     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
2332       if (LP.isCatch(I))
2333         Vals.push_back(LandingPadInst::Catch);
2334       else
2335         Vals.push_back(LandingPadInst::Filter);
2336       pushValueAndType(LP.getClause(I), InstID, Vals);
2337     }
2338     break;
2339   }
2340 
2341   case Instruction::Alloca: {
2342     Code = bitc::FUNC_CODE_INST_ALLOCA;
2343     const AllocaInst &AI = cast<AllocaInst>(I);
2344     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
2345     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2346     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
2347     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
2348     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
2349            "not enough bits for maximum alignment");
2350     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
2351     AlignRecord |= AI.isUsedWithInAlloca() << 5;
2352     AlignRecord |= 1 << 6;
2353     AlignRecord |= AI.isSwiftError() << 7;
2354     Vals.push_back(AlignRecord);
2355     break;
2356   }
2357 
2358   case Instruction::Load:
2359     if (cast<LoadInst>(I).isAtomic()) {
2360       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
2361       pushValueAndType(I.getOperand(0), InstID, Vals);
2362     } else {
2363       Code = bitc::FUNC_CODE_INST_LOAD;
2364       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
2365         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
2366     }
2367     Vals.push_back(VE.getTypeID(I.getType()));
2368     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
2369     Vals.push_back(cast<LoadInst>(I).isVolatile());
2370     if (cast<LoadInst>(I).isAtomic()) {
2371       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
2372       Vals.push_back(getEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
2373     }
2374     break;
2375   case Instruction::Store:
2376     if (cast<StoreInst>(I).isAtomic())
2377       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
2378     else
2379       Code = bitc::FUNC_CODE_INST_STORE;
2380     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
2381     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
2382     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
2383     Vals.push_back(cast<StoreInst>(I).isVolatile());
2384     if (cast<StoreInst>(I).isAtomic()) {
2385       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
2386       Vals.push_back(getEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
2387     }
2388     break;
2389   case Instruction::AtomicCmpXchg:
2390     Code = bitc::FUNC_CODE_INST_CMPXCHG;
2391     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
2392     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
2393     pushValue(I.getOperand(2), InstID, Vals);        // newval.
2394     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
2395     Vals.push_back(
2396         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
2397     Vals.push_back(
2398         getEncodedSynchScope(cast<AtomicCmpXchgInst>(I).getSynchScope()));
2399     Vals.push_back(
2400         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
2401     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
2402     break;
2403   case Instruction::AtomicRMW:
2404     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
2405     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
2406     pushValue(I.getOperand(1), InstID, Vals);        // val.
2407     Vals.push_back(
2408         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
2409     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
2410     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
2411     Vals.push_back(
2412         getEncodedSynchScope(cast<AtomicRMWInst>(I).getSynchScope()));
2413     break;
2414   case Instruction::Fence:
2415     Code = bitc::FUNC_CODE_INST_FENCE;
2416     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
2417     Vals.push_back(getEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
2418     break;
2419   case Instruction::Call: {
2420     const CallInst &CI = cast<CallInst>(I);
2421     FunctionType *FTy = CI.getFunctionType();
2422 
2423     if (CI.hasOperandBundles())
2424       writeOperandBundles(&CI, InstID);
2425 
2426     Code = bitc::FUNC_CODE_INST_CALL;
2427 
2428     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
2429 
2430     unsigned Flags = getOptimizationFlags(&I);
2431     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
2432                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
2433                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
2434                    1 << bitc::CALL_EXPLICIT_TYPE |
2435                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
2436                    unsigned(Flags != 0) << bitc::CALL_FMF);
2437     if (Flags != 0)
2438       Vals.push_back(Flags);
2439 
2440     Vals.push_back(VE.getTypeID(FTy));
2441     pushValueAndType(CI.getCalledValue(), InstID, Vals); // Callee
2442 
2443     // Emit value #'s for the fixed parameters.
2444     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
2445       // Check for labels (can happen with asm labels).
2446       if (FTy->getParamType(i)->isLabelTy())
2447         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
2448       else
2449         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
2450     }
2451 
2452     // Emit type/value pairs for varargs params.
2453     if (FTy->isVarArg()) {
2454       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
2455            i != e; ++i)
2456         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
2457     }
2458     break;
2459   }
2460   case Instruction::VAArg:
2461     Code = bitc::FUNC_CODE_INST_VAARG;
2462     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
2463     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
2464     Vals.push_back(VE.getTypeID(I.getType())); // restype.
2465     break;
2466   }
2467 
2468   Stream.EmitRecord(Code, Vals, AbbrevToUse);
2469   Vals.clear();
2470 }
2471 
2472 /// Emit names for globals/functions etc. \p IsModuleLevel is true when
2473 /// we are writing the module-level VST, where we are including a function
2474 /// bitcode index and need to backpatch the VST forward declaration record.
2475 void ModuleBitcodeWriter::writeValueSymbolTable(
2476     const ValueSymbolTable &VST, bool IsModuleLevel,
2477     DenseMap<const Function *, uint64_t> *FunctionToBitcodeIndex) {
2478   if (VST.empty()) {
2479     // writeValueSymbolTableForwardDecl should have returned early as
2480     // well. Ensure this handling remains in sync by asserting that
2481     // the placeholder offset is not set.
2482     assert(!IsModuleLevel || !hasVSTOffsetPlaceholder());
2483     return;
2484   }
2485 
2486   if (IsModuleLevel && hasVSTOffsetPlaceholder()) {
2487     // Get the offset of the VST we are writing, and backpatch it into
2488     // the VST forward declaration record.
2489     uint64_t VSTOffset = Stream.GetCurrentBitNo();
2490     // The BitcodeStartBit was the stream offset of the actual bitcode
2491     // (e.g. excluding any initial darwin header).
2492     VSTOffset -= bitcodeStartBit();
2493     assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
2494     Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32);
2495   }
2496 
2497   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
2498 
2499   // For the module-level VST, add abbrev Ids for the VST_CODE_FNENTRY
2500   // records, which are not used in the per-function VSTs.
2501   unsigned FnEntry8BitAbbrev;
2502   unsigned FnEntry7BitAbbrev;
2503   unsigned FnEntry6BitAbbrev;
2504   if (IsModuleLevel && hasVSTOffsetPlaceholder()) {
2505     // 8-bit fixed-width VST_CODE_FNENTRY function strings.
2506     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2507     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2508     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2509     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2510     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2511     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2512     FnEntry8BitAbbrev = Stream.EmitAbbrev(Abbv);
2513 
2514     // 7-bit fixed width VST_CODE_FNENTRY function strings.
2515     Abbv = new BitCodeAbbrev();
2516     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2517     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2518     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2519     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2520     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2521     FnEntry7BitAbbrev = Stream.EmitAbbrev(Abbv);
2522 
2523     // 6-bit char6 VST_CODE_FNENTRY function strings.
2524     Abbv = new BitCodeAbbrev();
2525     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2526     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2527     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2528     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2529     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2530     FnEntry6BitAbbrev = Stream.EmitAbbrev(Abbv);
2531   }
2532 
2533   // FIXME: Set up the abbrev, we know how many values there are!
2534   // FIXME: We know if the type names can use 7-bit ascii.
2535   SmallVector<unsigned, 64> NameVals;
2536 
2537   for (const ValueName &Name : VST) {
2538     // Figure out the encoding to use for the name.
2539     StringEncoding Bits =
2540         getStringEncoding(Name.getKeyData(), Name.getKeyLength());
2541 
2542     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
2543     NameVals.push_back(VE.getValueID(Name.getValue()));
2544 
2545     Function *F = dyn_cast<Function>(Name.getValue());
2546     if (!F) {
2547       // If value is an alias, need to get the aliased base object to
2548       // see if it is a function.
2549       auto *GA = dyn_cast<GlobalAlias>(Name.getValue());
2550       if (GA && GA->getBaseObject())
2551         F = dyn_cast<Function>(GA->getBaseObject());
2552     }
2553 
2554     // VST_CODE_ENTRY:   [valueid, namechar x N]
2555     // VST_CODE_FNENTRY: [valueid, funcoffset, namechar x N]
2556     // VST_CODE_BBENTRY: [bbid, namechar x N]
2557     unsigned Code;
2558     if (isa<BasicBlock>(Name.getValue())) {
2559       Code = bitc::VST_CODE_BBENTRY;
2560       if (Bits == SE_Char6)
2561         AbbrevToUse = VST_BBENTRY_6_ABBREV;
2562     } else if (F && !F->isDeclaration()) {
2563       // Must be the module-level VST, where we pass in the Index and
2564       // have a VSTOffsetPlaceholder. The function-level VST should not
2565       // contain any Function symbols.
2566       assert(FunctionToBitcodeIndex);
2567       assert(hasVSTOffsetPlaceholder());
2568 
2569       // Save the word offset of the function (from the start of the
2570       // actual bitcode written to the stream).
2571       uint64_t BitcodeIndex = (*FunctionToBitcodeIndex)[F] - bitcodeStartBit();
2572       assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
2573       NameVals.push_back(BitcodeIndex / 32);
2574 
2575       Code = bitc::VST_CODE_FNENTRY;
2576       AbbrevToUse = FnEntry8BitAbbrev;
2577       if (Bits == SE_Char6)
2578         AbbrevToUse = FnEntry6BitAbbrev;
2579       else if (Bits == SE_Fixed7)
2580         AbbrevToUse = FnEntry7BitAbbrev;
2581     } else {
2582       Code = bitc::VST_CODE_ENTRY;
2583       if (Bits == SE_Char6)
2584         AbbrevToUse = VST_ENTRY_6_ABBREV;
2585       else if (Bits == SE_Fixed7)
2586         AbbrevToUse = VST_ENTRY_7_ABBREV;
2587     }
2588 
2589     for (const auto P : Name.getKey())
2590       NameVals.push_back((unsigned char)P);
2591 
2592     // Emit the finished record.
2593     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
2594     NameVals.clear();
2595   }
2596   Stream.ExitBlock();
2597 }
2598 
2599 /// Emit function names and summary offsets for the combined index
2600 /// used by ThinLTO.
2601 void IndexBitcodeWriter::writeCombinedValueSymbolTable() {
2602   assert(hasVSTOffsetPlaceholder() && "Expected non-zero VSTOffsetPlaceholder");
2603   // Get the offset of the VST we are writing, and backpatch it into
2604   // the VST forward declaration record.
2605   uint64_t VSTOffset = Stream.GetCurrentBitNo();
2606   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
2607   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32);
2608 
2609   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
2610 
2611   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2612   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_COMBINED_GVDEFENTRY));
2613   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
2614   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // sumoffset
2615   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // guid
2616   unsigned DefEntryAbbrev = Stream.EmitAbbrev(Abbv);
2617 
2618   Abbv = new BitCodeAbbrev();
2619   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_COMBINED_ENTRY));
2620   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
2621   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // refguid
2622   unsigned EntryAbbrev = Stream.EmitAbbrev(Abbv);
2623 
2624   SmallVector<uint64_t, 64> NameVals;
2625 
2626   for (const auto &FII : Index) {
2627     GlobalValue::GUID FuncGUID = FII.first;
2628     unsigned ValueId = popValueId(FuncGUID);
2629 
2630     for (const auto &FI : FII.second) {
2631       // VST_CODE_COMBINED_GVDEFENTRY: [valueid, sumoffset, guid]
2632       NameVals.push_back(ValueId);
2633       NameVals.push_back(FI->bitcodeIndex());
2634       NameVals.push_back(FuncGUID);
2635 
2636       // Emit the finished record.
2637       Stream.EmitRecord(bitc::VST_CODE_COMBINED_GVDEFENTRY, NameVals,
2638                         DefEntryAbbrev);
2639       NameVals.clear();
2640     }
2641   }
2642   for (const auto &GVI : valueIds()) {
2643     // VST_CODE_COMBINED_ENTRY: [valueid, refguid]
2644     NameVals.push_back(GVI.second);
2645     NameVals.push_back(GVI.first);
2646 
2647     // Emit the finished record.
2648     Stream.EmitRecord(bitc::VST_CODE_COMBINED_ENTRY, NameVals, EntryAbbrev);
2649     NameVals.clear();
2650   }
2651   Stream.ExitBlock();
2652 }
2653 
2654 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
2655   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
2656   unsigned Code;
2657   if (isa<BasicBlock>(Order.V))
2658     Code = bitc::USELIST_CODE_BB;
2659   else
2660     Code = bitc::USELIST_CODE_DEFAULT;
2661 
2662   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
2663   Record.push_back(VE.getValueID(Order.V));
2664   Stream.EmitRecord(Code, Record);
2665 }
2666 
2667 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
2668   assert(VE.shouldPreserveUseListOrder() &&
2669          "Expected to be preserving use-list order");
2670 
2671   auto hasMore = [&]() {
2672     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
2673   };
2674   if (!hasMore())
2675     // Nothing to do.
2676     return;
2677 
2678   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
2679   while (hasMore()) {
2680     writeUseList(std::move(VE.UseListOrders.back()));
2681     VE.UseListOrders.pop_back();
2682   }
2683   Stream.ExitBlock();
2684 }
2685 
2686 /// Emit a function body to the module stream.
2687 void ModuleBitcodeWriter::writeFunction(
2688     const Function &F,
2689     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
2690   // Save the bitcode index of the start of this function block for recording
2691   // in the VST.
2692   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
2693 
2694   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
2695   VE.incorporateFunction(F);
2696 
2697   SmallVector<unsigned, 64> Vals;
2698 
2699   // Emit the number of basic blocks, so the reader can create them ahead of
2700   // time.
2701   Vals.push_back(VE.getBasicBlocks().size());
2702   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
2703   Vals.clear();
2704 
2705   // If there are function-local constants, emit them now.
2706   unsigned CstStart, CstEnd;
2707   VE.getFunctionConstantRange(CstStart, CstEnd);
2708   writeConstants(CstStart, CstEnd, false);
2709 
2710   // If there is function-local metadata, emit it now.
2711   writeFunctionMetadata(F);
2712 
2713   // Keep a running idea of what the instruction ID is.
2714   unsigned InstID = CstEnd;
2715 
2716   bool NeedsMetadataAttachment = F.hasMetadata();
2717 
2718   DILocation *LastDL = nullptr;
2719   // Finally, emit all the instructions, in order.
2720   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
2721     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
2722          I != E; ++I) {
2723       writeInstruction(*I, InstID, Vals);
2724 
2725       if (!I->getType()->isVoidTy())
2726         ++InstID;
2727 
2728       // If the instruction has metadata, write a metadata attachment later.
2729       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
2730 
2731       // If the instruction has a debug location, emit it.
2732       DILocation *DL = I->getDebugLoc();
2733       if (!DL)
2734         continue;
2735 
2736       if (DL == LastDL) {
2737         // Just repeat the same debug loc as last time.
2738         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
2739         continue;
2740       }
2741 
2742       Vals.push_back(DL->getLine());
2743       Vals.push_back(DL->getColumn());
2744       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
2745       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
2746       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
2747       Vals.clear();
2748 
2749       LastDL = DL;
2750     }
2751 
2752   // Emit names for all the instructions etc.
2753   writeValueSymbolTable(F.getValueSymbolTable());
2754 
2755   if (NeedsMetadataAttachment)
2756     writeMetadataAttachment(F);
2757   if (VE.shouldPreserveUseListOrder())
2758     writeUseListBlock(&F);
2759   VE.purgeFunction();
2760   Stream.ExitBlock();
2761 }
2762 
2763 // Emit blockinfo, which defines the standard abbreviations etc.
2764 void ModuleBitcodeWriter::writeBlockInfo() {
2765   // We only want to emit block info records for blocks that have multiple
2766   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
2767   // Other blocks can define their abbrevs inline.
2768   Stream.EnterBlockInfoBlock(2);
2769 
2770   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
2771     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2772     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
2773     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2774     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2775     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2776     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
2777         VST_ENTRY_8_ABBREV)
2778       llvm_unreachable("Unexpected abbrev ordering!");
2779   }
2780 
2781   { // 7-bit fixed width VST_CODE_ENTRY strings.
2782     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2783     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2784     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2785     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2786     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2787     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
2788         VST_ENTRY_7_ABBREV)
2789       llvm_unreachable("Unexpected abbrev ordering!");
2790   }
2791   { // 6-bit char6 VST_CODE_ENTRY strings.
2792     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2793     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2794     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2795     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2796     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2797     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
2798         VST_ENTRY_6_ABBREV)
2799       llvm_unreachable("Unexpected abbrev ordering!");
2800   }
2801   { // 6-bit char6 VST_CODE_BBENTRY strings.
2802     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2803     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
2804     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2805     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2806     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2807     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
2808         VST_BBENTRY_6_ABBREV)
2809       llvm_unreachable("Unexpected abbrev ordering!");
2810   }
2811 
2812 
2813 
2814   { // SETTYPE abbrev for CONSTANTS_BLOCK.
2815     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2816     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
2817     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
2818                               VE.computeBitsRequiredForTypeIndicies()));
2819     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
2820         CONSTANTS_SETTYPE_ABBREV)
2821       llvm_unreachable("Unexpected abbrev ordering!");
2822   }
2823 
2824   { // INTEGER abbrev for CONSTANTS_BLOCK.
2825     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2826     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
2827     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2828     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
2829         CONSTANTS_INTEGER_ABBREV)
2830       llvm_unreachable("Unexpected abbrev ordering!");
2831   }
2832 
2833   { // CE_CAST abbrev for CONSTANTS_BLOCK.
2834     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2835     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
2836     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
2837     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
2838                               VE.computeBitsRequiredForTypeIndicies()));
2839     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
2840 
2841     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
2842         CONSTANTS_CE_CAST_Abbrev)
2843       llvm_unreachable("Unexpected abbrev ordering!");
2844   }
2845   { // NULL abbrev for CONSTANTS_BLOCK.
2846     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2847     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
2848     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
2849         CONSTANTS_NULL_Abbrev)
2850       llvm_unreachable("Unexpected abbrev ordering!");
2851   }
2852 
2853   // FIXME: This should only use space for first class types!
2854 
2855   { // INST_LOAD abbrev for FUNCTION_BLOCK.
2856     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2857     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
2858     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
2859     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
2860                               VE.computeBitsRequiredForTypeIndicies()));
2861     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
2862     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
2863     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2864         FUNCTION_INST_LOAD_ABBREV)
2865       llvm_unreachable("Unexpected abbrev ordering!");
2866   }
2867   { // INST_BINOP abbrev for FUNCTION_BLOCK.
2868     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2869     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2870     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2871     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2872     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2873     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2874         FUNCTION_INST_BINOP_ABBREV)
2875       llvm_unreachable("Unexpected abbrev ordering!");
2876   }
2877   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
2878     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2879     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2880     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2881     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2882     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2883     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
2884     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2885         FUNCTION_INST_BINOP_FLAGS_ABBREV)
2886       llvm_unreachable("Unexpected abbrev ordering!");
2887   }
2888   { // INST_CAST abbrev for FUNCTION_BLOCK.
2889     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2890     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
2891     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
2892     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
2893                               VE.computeBitsRequiredForTypeIndicies()));
2894     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
2895     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2896         FUNCTION_INST_CAST_ABBREV)
2897       llvm_unreachable("Unexpected abbrev ordering!");
2898   }
2899 
2900   { // INST_RET abbrev for FUNCTION_BLOCK.
2901     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2902     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2903     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2904         FUNCTION_INST_RET_VOID_ABBREV)
2905       llvm_unreachable("Unexpected abbrev ordering!");
2906   }
2907   { // INST_RET abbrev for FUNCTION_BLOCK.
2908     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2909     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2910     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
2911     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2912         FUNCTION_INST_RET_VAL_ABBREV)
2913       llvm_unreachable("Unexpected abbrev ordering!");
2914   }
2915   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
2916     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2917     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
2918     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2919         FUNCTION_INST_UNREACHABLE_ABBREV)
2920       llvm_unreachable("Unexpected abbrev ordering!");
2921   }
2922   {
2923     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2924     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
2925     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2926     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
2927                               Log2_32_Ceil(VE.getTypes().size() + 1)));
2928     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2929     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2930     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2931         FUNCTION_INST_GEP_ABBREV)
2932       llvm_unreachable("Unexpected abbrev ordering!");
2933   }
2934 
2935   Stream.ExitBlock();
2936 }
2937 
2938 /// Write the module path strings, currently only used when generating
2939 /// a combined index file.
2940 void IndexBitcodeWriter::writeModStrings() {
2941   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
2942 
2943   // TODO: See which abbrev sizes we actually need to emit
2944 
2945   // 8-bit fixed-width MST_ENTRY strings.
2946   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2947   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
2948   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2949   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2950   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2951   unsigned Abbrev8Bit = Stream.EmitAbbrev(Abbv);
2952 
2953   // 7-bit fixed width MST_ENTRY strings.
2954   Abbv = new BitCodeAbbrev();
2955   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
2956   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2957   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2958   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2959   unsigned Abbrev7Bit = Stream.EmitAbbrev(Abbv);
2960 
2961   // 6-bit char6 MST_ENTRY strings.
2962   Abbv = new BitCodeAbbrev();
2963   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
2964   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2965   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2966   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2967   unsigned Abbrev6Bit = Stream.EmitAbbrev(Abbv);
2968 
2969   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
2970   Abbv = new BitCodeAbbrev();
2971   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
2972   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2973   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2974   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2975   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2976   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2977   unsigned AbbrevHash = Stream.EmitAbbrev(Abbv);
2978 
2979   SmallVector<unsigned, 64> Vals;
2980   for (const auto &MPSE : Index.modulePaths()) {
2981     StringEncoding Bits =
2982         getStringEncoding(MPSE.getKey().data(), MPSE.getKey().size());
2983     unsigned AbbrevToUse = Abbrev8Bit;
2984     if (Bits == SE_Char6)
2985       AbbrevToUse = Abbrev6Bit;
2986     else if (Bits == SE_Fixed7)
2987       AbbrevToUse = Abbrev7Bit;
2988 
2989     Vals.push_back(MPSE.getValue().first);
2990 
2991     for (const auto P : MPSE.getKey())
2992       Vals.push_back((unsigned char)P);
2993 
2994     // Emit the finished record.
2995     Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
2996 
2997     Vals.clear();
2998     // Emit an optional hash for the module now
2999     auto &Hash = MPSE.getValue().second;
3000     bool AllZero = true; // Detect if the hash is empty, and do not generate it
3001     for (auto Val : Hash) {
3002       if (Val)
3003         AllZero = false;
3004       Vals.push_back(Val);
3005     }
3006     if (!AllZero) {
3007       // Emit the hash record.
3008       Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3009     }
3010 
3011     Vals.clear();
3012   }
3013   Stream.ExitBlock();
3014 }
3015 
3016 // Helper to emit a single function summary record.
3017 void ModuleBitcodeWriter::writePerModuleFunctionSummaryRecord(
3018     SmallVector<uint64_t, 64> &NameVals, GlobalValueInfo *Info,
3019     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3020     const Function &F) {
3021   NameVals.push_back(ValueID);
3022 
3023   FunctionSummary *FS = cast<FunctionSummary>(Info->summary());
3024   NameVals.push_back(getEncodedLinkage(FS->linkage()));
3025   NameVals.push_back(FS->instCount());
3026   NameVals.push_back(FS->refs().size());
3027 
3028   for (auto &RI : FS->refs())
3029     NameVals.push_back(VE.getValueID(RI.getValue()));
3030 
3031   bool HasProfileData = F.getEntryCount().hasValue();
3032   for (auto &ECI : FS->calls()) {
3033     NameVals.push_back(VE.getValueID(ECI.first.getValue()));
3034     assert(ECI.second.CallsiteCount > 0 && "Expected at least one callsite");
3035     NameVals.push_back(ECI.second.CallsiteCount);
3036     if (HasProfileData)
3037       NameVals.push_back(ECI.second.ProfileCount);
3038   }
3039 
3040   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3041   unsigned Code =
3042       (HasProfileData ? bitc::FS_PERMODULE_PROFILE : bitc::FS_PERMODULE);
3043 
3044   // Emit the finished record.
3045   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3046   NameVals.clear();
3047 }
3048 
3049 // Collect the global value references in the given variable's initializer,
3050 // and emit them in a summary record.
3051 void ModuleBitcodeWriter::writeModuleLevelReferences(
3052     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3053     unsigned FSModRefsAbbrev) {
3054   // Only interested in recording variable defs in the summary.
3055   if (V.isDeclaration())
3056     return;
3057   NameVals.push_back(VE.getValueID(&V));
3058   NameVals.push_back(getEncodedLinkage(V.getLinkage()));
3059   auto *Info = Index->getGlobalValueInfo(V);
3060   GlobalVarSummary *VS = cast<GlobalVarSummary>(Info->summary());
3061   for (auto Ref : VS->refs())
3062     NameVals.push_back(VE.getValueID(Ref.getValue()));
3063   Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3064                     FSModRefsAbbrev);
3065   NameVals.clear();
3066 }
3067 
3068 /// Emit the per-module summary section alongside the rest of
3069 /// the module's bitcode.
3070 void ModuleBitcodeWriter::writePerModuleGlobalValueSummary() {
3071   if (M.empty())
3072     return;
3073 
3074   if (Index->begin() == Index->end())
3075     return;
3076 
3077   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
3078 
3079   // Abbrev for FS_PERMODULE.
3080   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3081   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
3082   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3083   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // linkage
3084   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3085   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3086   // numrefs x valueid, n x (valueid, callsitecount)
3087   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3088   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3089   unsigned FSCallsAbbrev = Stream.EmitAbbrev(Abbv);
3090 
3091   // Abbrev for FS_PERMODULE_PROFILE.
3092   Abbv = new BitCodeAbbrev();
3093   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
3094   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3095   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // linkage
3096   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3097   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3098   // numrefs x valueid, n x (valueid, callsitecount, profilecount)
3099   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3100   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3101   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(Abbv);
3102 
3103   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
3104   Abbv = new BitCodeAbbrev();
3105   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
3106   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3107   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // linkage
3108   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
3109   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3110   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(Abbv);
3111 
3112   // Abbrev for FS_ALIAS.
3113   Abbv = new BitCodeAbbrev();
3114   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
3115   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3116   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // linkage
3117   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3118   unsigned FSAliasAbbrev = Stream.EmitAbbrev(Abbv);
3119 
3120   SmallVector<uint64_t, 64> NameVals;
3121   // Iterate over the list of functions instead of the Index to
3122   // ensure the ordering is stable.
3123   for (const Function &F : M) {
3124     if (F.isDeclaration())
3125       continue;
3126     // Summary emission does not support anonymous functions, they have to
3127     // renamed using the anonymous function renaming pass.
3128     if (!F.hasName())
3129       report_fatal_error("Unexpected anonymous function when writing summary");
3130 
3131     auto *Info = Index->getGlobalValueInfo(F);
3132     writePerModuleFunctionSummaryRecord(
3133         NameVals, Info,
3134         VE.getValueID(M.getValueSymbolTable().lookup(F.getName())),
3135         FSCallsAbbrev, FSCallsProfileAbbrev, F);
3136   }
3137 
3138   // Capture references from GlobalVariable initializers, which are outside
3139   // of a function scope.
3140   for (const GlobalVariable &G : M.globals())
3141     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev);
3142 
3143   for (const GlobalAlias &A : M.aliases()) {
3144     auto *Aliasee = A.getBaseObject();
3145     if (!Aliasee->hasName())
3146       // Nameless function don't have an entry in the summary, skip it.
3147       continue;
3148     auto AliasId = VE.getValueID(&A);
3149     auto AliaseeId = VE.getValueID(Aliasee);
3150     NameVals.push_back(AliasId);
3151     NameVals.push_back(getEncodedLinkage(A.getLinkage()));
3152     NameVals.push_back(AliaseeId);
3153     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
3154     NameVals.clear();
3155   }
3156 
3157   Stream.ExitBlock();
3158 }
3159 
3160 /// Emit the combined summary section into the combined index file.
3161 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
3162   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
3163 
3164   // Abbrev for FS_COMBINED.
3165   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3166   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
3167   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3168   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // linkage
3169   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3170   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3171   // numrefs x valueid, n x (valueid, callsitecount)
3172   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3173   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3174   unsigned FSCallsAbbrev = Stream.EmitAbbrev(Abbv);
3175 
3176   // Abbrev for FS_COMBINED_PROFILE.
3177   Abbv = new BitCodeAbbrev();
3178   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
3179   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3180   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // linkage
3181   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3182   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3183   // numrefs x valueid, n x (valueid, callsitecount, profilecount)
3184   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3185   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3186   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(Abbv);
3187 
3188   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
3189   Abbv = new BitCodeAbbrev();
3190   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
3191   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3192   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // linkage
3193   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
3194   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3195   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(Abbv);
3196 
3197   // Abbrev for FS_COMBINED_ALIAS.
3198   Abbv = new BitCodeAbbrev();
3199   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
3200   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3201   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // linkage
3202   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // offset
3203   unsigned FSAliasAbbrev = Stream.EmitAbbrev(Abbv);
3204 
3205   // The aliases are emitted as a post-pass, and will point to the summary
3206   // offset id of the aliasee. For this purpose we need to be able to get back
3207   // from the summary to the offset
3208   SmallVector<GlobalValueInfo *, 64> Aliases;
3209   DenseMap<const GlobalValueSummary *, uint64_t> SummaryToOffsetMap;
3210 
3211   SmallVector<uint64_t, 64> NameVals;
3212   for (const auto &FII : Index) {
3213     for (auto &FI : FII.second) {
3214       GlobalValueSummary *S = FI->summary();
3215       assert(S);
3216       if (isa<AliasSummary>(S)) {
3217         // Will process aliases as a post-pass because the reader wants all
3218         // global to be loaded first.
3219         Aliases.push_back(FI.get());
3220         continue;
3221       }
3222 
3223       if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
3224         NameVals.push_back(Index.getModuleId(VS->modulePath()));
3225         NameVals.push_back(getEncodedLinkage(VS->linkage()));
3226         for (auto &RI : VS->refs()) {
3227           NameVals.push_back(getValueId(RI.getGUID()));
3228         }
3229 
3230         // Record the starting offset of this summary entry for use
3231         // in the VST entry. Add the current code size since the
3232         // reader will invoke readRecord after the abbrev id read.
3233         FI->setBitcodeIndex(Stream.GetCurrentBitNo() +
3234                             Stream.GetAbbrevIDWidth());
3235         // Store temporarily the offset in the map for a possible alias.
3236         SummaryToOffsetMap[S] = FI->bitcodeIndex();
3237 
3238         // Emit the finished record.
3239         Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
3240                           FSModRefsAbbrev);
3241         NameVals.clear();
3242         continue;
3243       }
3244 
3245       auto *FS = cast<FunctionSummary>(S);
3246       NameVals.push_back(Index.getModuleId(FS->modulePath()));
3247       NameVals.push_back(getEncodedLinkage(FS->linkage()));
3248       NameVals.push_back(FS->instCount());
3249       NameVals.push_back(FS->refs().size());
3250 
3251       for (auto &RI : FS->refs()) {
3252         NameVals.push_back(getValueId(RI.getGUID()));
3253       }
3254 
3255       bool HasProfileData = false;
3256       for (auto &EI : FS->calls()) {
3257         HasProfileData |= EI.second.ProfileCount != 0;
3258         if (HasProfileData)
3259           break;
3260       }
3261 
3262       for (auto &EI : FS->calls()) {
3263         // If this GUID doesn't have a value id, it doesn't have a function
3264         // summary and we don't need to record any calls to it.
3265         if (!hasValueId(EI.first.getGUID()))
3266           continue;
3267         NameVals.push_back(getValueId(EI.first.getGUID()));
3268         assert(EI.second.CallsiteCount > 0 && "Expected at least one callsite");
3269         NameVals.push_back(EI.second.CallsiteCount);
3270         if (HasProfileData)
3271           NameVals.push_back(EI.second.ProfileCount);
3272       }
3273 
3274       // Record the starting offset of this summary entry for use
3275       // in the VST entry. Add the current code size since the
3276       // reader will invoke readRecord after the abbrev id read.
3277       FI->setBitcodeIndex(Stream.GetCurrentBitNo() + Stream.GetAbbrevIDWidth());
3278       // Store temporarily the offset in the map for a possible alias.
3279       SummaryToOffsetMap[S] = FI->bitcodeIndex();
3280 
3281       unsigned FSAbbrev =
3282           (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3283       unsigned Code =
3284           (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
3285 
3286       // Emit the finished record.
3287       Stream.EmitRecord(Code, NameVals, FSAbbrev);
3288       NameVals.clear();
3289     }
3290   }
3291 
3292   for (auto GVI : Aliases) {
3293     AliasSummary *AS = cast<AliasSummary>(GVI->summary());
3294     NameVals.push_back(Index.getModuleId(AS->modulePath()));
3295     NameVals.push_back(getEncodedLinkage(AS->linkage()));
3296     auto AliaseeOffset = SummaryToOffsetMap[&AS->getAliasee()];
3297     assert(AliaseeOffset);
3298     NameVals.push_back(AliaseeOffset);
3299 
3300     // Record the starting offset of this summary entry for use
3301     // in the VST entry. Add the current code size since the
3302     // reader will invoke readRecord after the abbrev id read.
3303     GVI->setBitcodeIndex(Stream.GetCurrentBitNo() + Stream.GetAbbrevIDWidth());
3304 
3305     // Emit the finished record.
3306     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
3307     NameVals.clear();
3308   }
3309 
3310   Stream.ExitBlock();
3311 }
3312 
3313 void ModuleBitcodeWriter::writeIdentificationBlock() {
3314   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
3315 
3316   // Write the "user readable" string identifying the bitcode producer
3317   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3318   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
3319   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3320   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3321   auto StringAbbrev = Stream.EmitAbbrev(Abbv);
3322   writeStringRecord(bitc::IDENTIFICATION_CODE_STRING,
3323                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
3324 
3325   // Write the epoch version
3326   Abbv = new BitCodeAbbrev();
3327   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
3328   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3329   auto EpochAbbrev = Stream.EmitAbbrev(Abbv);
3330   SmallVector<unsigned, 1> Vals = {bitc::BITCODE_CURRENT_EPOCH};
3331   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
3332   Stream.ExitBlock();
3333 }
3334 
3335 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
3336   // Emit the module's hash.
3337   // MODULE_CODE_HASH: [5*i32]
3338   SHA1 Hasher;
3339   Hasher.update(ArrayRef<uint8_t>((uint8_t *)&(Buffer)[BlockStartPos],
3340                                   Buffer.size() - BlockStartPos));
3341   auto Hash = Hasher.result();
3342   SmallVector<uint64_t, 20> Vals;
3343   auto LShift = [&](unsigned char Val, unsigned Amount)
3344                     -> uint64_t { return ((uint64_t)Val) << Amount; };
3345   for (int Pos = 0; Pos < 20; Pos += 4) {
3346     uint32_t SubHash = LShift(Hash[Pos + 0], 24);
3347     SubHash |= LShift(Hash[Pos + 1], 16) | LShift(Hash[Pos + 2], 8) |
3348                (unsigned)(unsigned char)Hash[Pos + 3];
3349     Vals.push_back(SubHash);
3350   }
3351 
3352   // Emit the finished record.
3353   Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
3354 }
3355 
3356 void BitcodeWriter::write() {
3357   // Emit the file header first.
3358   writeBitcodeHeader();
3359 
3360   writeBlocks();
3361 }
3362 
3363 void ModuleBitcodeWriter::writeBlocks() {
3364   writeIdentificationBlock();
3365   writeModule();
3366 }
3367 
3368 void IndexBitcodeWriter::writeBlocks() {
3369   // Index contains only a single outer (module) block.
3370   writeIndex();
3371 }
3372 
3373 void ModuleBitcodeWriter::writeModule() {
3374   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
3375   size_t BlockStartPos = Buffer.size();
3376 
3377   SmallVector<unsigned, 1> Vals;
3378   unsigned CurVersion = 1;
3379   Vals.push_back(CurVersion);
3380   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
3381 
3382   // Emit blockinfo, which defines the standard abbreviations etc.
3383   writeBlockInfo();
3384 
3385   // Emit information about attribute groups.
3386   writeAttributeGroupTable();
3387 
3388   // Emit information about parameter attributes.
3389   writeAttributeTable();
3390 
3391   // Emit information describing all of the types in the module.
3392   writeTypeTable();
3393 
3394   writeComdats();
3395 
3396   // Emit top-level description of module, including target triple, inline asm,
3397   // descriptors for global variables, and function prototype info.
3398   writeModuleInfo();
3399 
3400   // Emit constants.
3401   writeModuleConstants();
3402 
3403   // Emit metadata.
3404   writeModuleMetadata();
3405 
3406   // Emit metadata.
3407   writeModuleMetadataStore();
3408 
3409   // Emit module-level use-lists.
3410   if (VE.shouldPreserveUseListOrder())
3411     writeUseListBlock(nullptr);
3412 
3413   writeOperandBundleTags();
3414 
3415   // Emit function bodies.
3416   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
3417   for (Module::const_iterator F = M.begin(), E = M.end(); F != E; ++F)
3418     if (!F->isDeclaration())
3419       writeFunction(*F, FunctionToBitcodeIndex);
3420 
3421   // Need to write after the above call to WriteFunction which populates
3422   // the summary information in the index.
3423   if (Index)
3424     writePerModuleGlobalValueSummary();
3425 
3426   writeValueSymbolTable(M.getValueSymbolTable(),
3427                         /* IsModuleLevel */ true, &FunctionToBitcodeIndex);
3428 
3429   if (GenerateHash) {
3430     writeModuleHash(BlockStartPos);
3431   }
3432 
3433   Stream.ExitBlock();
3434 }
3435 
3436 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
3437                                uint32_t &Position) {
3438   support::endian::write32le(&Buffer[Position], Value);
3439   Position += 4;
3440 }
3441 
3442 /// If generating a bc file on darwin, we have to emit a
3443 /// header and trailer to make it compatible with the system archiver.  To do
3444 /// this we emit the following header, and then emit a trailer that pads the
3445 /// file out to be a multiple of 16 bytes.
3446 ///
3447 /// struct bc_header {
3448 ///   uint32_t Magic;         // 0x0B17C0DE
3449 ///   uint32_t Version;       // Version, currently always 0.
3450 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
3451 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
3452 ///   uint32_t CPUType;       // CPU specifier.
3453 ///   ... potentially more later ...
3454 /// };
3455 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
3456                                          const Triple &TT) {
3457   unsigned CPUType = ~0U;
3458 
3459   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
3460   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
3461   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
3462   // specific constants here because they are implicitly part of the Darwin ABI.
3463   enum {
3464     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
3465     DARWIN_CPU_TYPE_X86        = 7,
3466     DARWIN_CPU_TYPE_ARM        = 12,
3467     DARWIN_CPU_TYPE_POWERPC    = 18
3468   };
3469 
3470   Triple::ArchType Arch = TT.getArch();
3471   if (Arch == Triple::x86_64)
3472     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
3473   else if (Arch == Triple::x86)
3474     CPUType = DARWIN_CPU_TYPE_X86;
3475   else if (Arch == Triple::ppc)
3476     CPUType = DARWIN_CPU_TYPE_POWERPC;
3477   else if (Arch == Triple::ppc64)
3478     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
3479   else if (Arch == Triple::arm || Arch == Triple::thumb)
3480     CPUType = DARWIN_CPU_TYPE_ARM;
3481 
3482   // Traditional Bitcode starts after header.
3483   assert(Buffer.size() >= BWH_HeaderSize &&
3484          "Expected header size to be reserved");
3485   unsigned BCOffset = BWH_HeaderSize;
3486   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
3487 
3488   // Write the magic and version.
3489   unsigned Position = 0;
3490   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
3491   writeInt32ToBuffer(0, Buffer, Position); // Version.
3492   writeInt32ToBuffer(BCOffset, Buffer, Position);
3493   writeInt32ToBuffer(BCSize, Buffer, Position);
3494   writeInt32ToBuffer(CPUType, Buffer, Position);
3495 
3496   // If the file is not a multiple of 16 bytes, insert dummy padding.
3497   while (Buffer.size() & 15)
3498     Buffer.push_back(0);
3499 }
3500 
3501 /// Helper to write the header common to all bitcode files.
3502 void BitcodeWriter::writeBitcodeHeader() {
3503   // Emit the file header.
3504   Stream.Emit((unsigned)'B', 8);
3505   Stream.Emit((unsigned)'C', 8);
3506   Stream.Emit(0x0, 4);
3507   Stream.Emit(0xC, 4);
3508   Stream.Emit(0xE, 4);
3509   Stream.Emit(0xD, 4);
3510 }
3511 
3512 /// WriteBitcodeToFile - Write the specified module to the specified output
3513 /// stream.
3514 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out,
3515                               bool ShouldPreserveUseListOrder,
3516                               const ModuleSummaryIndex *Index,
3517                               bool GenerateHash) {
3518   SmallVector<char, 0> Buffer;
3519   Buffer.reserve(256*1024);
3520 
3521   // If this is darwin or another generic macho target, reserve space for the
3522   // header.
3523   Triple TT(M->getTargetTriple());
3524   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
3525     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
3526 
3527   // Emit the module into the buffer.
3528   ModuleBitcodeWriter ModuleWriter(M, Buffer, ShouldPreserveUseListOrder, Index,
3529                                    GenerateHash);
3530   ModuleWriter.write();
3531 
3532   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
3533     emitDarwinBCHeaderAndTrailer(Buffer, TT);
3534 
3535   // Write the generated bitstream to "Out".
3536   Out.write((char*)&Buffer.front(), Buffer.size());
3537 }
3538 
3539 void IndexBitcodeWriter::writeIndex() {
3540   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
3541 
3542   SmallVector<unsigned, 1> Vals;
3543   unsigned CurVersion = 1;
3544   Vals.push_back(CurVersion);
3545   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
3546 
3547   // If we have a VST, write the VSTOFFSET record placeholder.
3548   writeValueSymbolTableForwardDecl();
3549 
3550   // Write the module paths in the combined index.
3551   writeModStrings();
3552 
3553   // Write the summary combined index records.
3554   writeCombinedGlobalValueSummary();
3555 
3556   // Need a special VST writer for the combined index (we don't have a
3557   // real VST and real values when this is invoked).
3558   writeCombinedValueSymbolTable();
3559 
3560   Stream.ExitBlock();
3561 }
3562 
3563 // Write the specified module summary index to the given raw output stream,
3564 // where it will be written in a new bitcode block. This is used when
3565 // writing the combined index file for ThinLTO.
3566 void llvm::WriteIndexToFile(const ModuleSummaryIndex &Index, raw_ostream &Out) {
3567   SmallVector<char, 0> Buffer;
3568   Buffer.reserve(256 * 1024);
3569 
3570   IndexBitcodeWriter IndexWriter(Buffer, Index);
3571   IndexWriter.write();
3572 
3573   Out.write((char *)&Buffer.front(), Buffer.size());
3574 }
3575