xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision c3ed48c1bdba86f5528778b39c2106ef82670e0c)
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 // Decode the flags for GlobalValue in the summary
790 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
791   uint64_t RawFlags = 0;
792   // Emit Linkage enum.
793   RawFlags |= Flags.Linkage; // 4 bits
794   return RawFlags;
795 }
796 
797 static unsigned getEncodedVisibility(const GlobalValue &GV) {
798   switch (GV.getVisibility()) {
799   case GlobalValue::DefaultVisibility:   return 0;
800   case GlobalValue::HiddenVisibility:    return 1;
801   case GlobalValue::ProtectedVisibility: return 2;
802   }
803   llvm_unreachable("Invalid visibility");
804 }
805 
806 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
807   switch (GV.getDLLStorageClass()) {
808   case GlobalValue::DefaultStorageClass:   return 0;
809   case GlobalValue::DLLImportStorageClass: return 1;
810   case GlobalValue::DLLExportStorageClass: return 2;
811   }
812   llvm_unreachable("Invalid DLL storage class");
813 }
814 
815 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
816   switch (GV.getThreadLocalMode()) {
817     case GlobalVariable::NotThreadLocal:         return 0;
818     case GlobalVariable::GeneralDynamicTLSModel: return 1;
819     case GlobalVariable::LocalDynamicTLSModel:   return 2;
820     case GlobalVariable::InitialExecTLSModel:    return 3;
821     case GlobalVariable::LocalExecTLSModel:      return 4;
822   }
823   llvm_unreachable("Invalid TLS model");
824 }
825 
826 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
827   switch (C.getSelectionKind()) {
828   case Comdat::Any:
829     return bitc::COMDAT_SELECTION_KIND_ANY;
830   case Comdat::ExactMatch:
831     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
832   case Comdat::Largest:
833     return bitc::COMDAT_SELECTION_KIND_LARGEST;
834   case Comdat::NoDuplicates:
835     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
836   case Comdat::SameSize:
837     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
838   }
839   llvm_unreachable("Invalid selection kind");
840 }
841 
842 void ModuleBitcodeWriter::writeComdats() {
843   SmallVector<unsigned, 64> Vals;
844   for (const Comdat *C : VE.getComdats()) {
845     // COMDAT: [selection_kind, name]
846     Vals.push_back(getEncodedComdatSelectionKind(*C));
847     size_t Size = C->getName().size();
848     assert(isUInt<32>(Size));
849     Vals.push_back(Size);
850     for (char Chr : C->getName())
851       Vals.push_back((unsigned char)Chr);
852     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
853     Vals.clear();
854   }
855 }
856 
857 /// Write a record that will eventually hold the word offset of the
858 /// module-level VST. For now the offset is 0, which will be backpatched
859 /// after the real VST is written. Saves the bit offset to backpatch.
860 void BitcodeWriter::writeValueSymbolTableForwardDecl() {
861   // Write a placeholder value in for the offset of the real VST,
862   // which is written after the function blocks so that it can include
863   // the offset of each function. The placeholder offset will be
864   // updated when the real VST is written.
865   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
866   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
867   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
868   // hold the real VST offset. Must use fixed instead of VBR as we don't
869   // know how many VBR chunks to reserve ahead of time.
870   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
871   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(Abbv);
872 
873   // Emit the placeholder
874   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
875   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
876 
877   // Compute and save the bit offset to the placeholder, which will be
878   // patched when the real VST is written. We can simply subtract the 32-bit
879   // fixed size from the current bit number to get the location to backpatch.
880   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
881 }
882 
883 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
884 
885 /// Determine the encoding to use for the given string name and length.
886 static StringEncoding getStringEncoding(const char *Str, unsigned StrLen) {
887   bool isChar6 = true;
888   for (const char *C = Str, *E = C + StrLen; C != E; ++C) {
889     if (isChar6)
890       isChar6 = BitCodeAbbrevOp::isChar6(*C);
891     if ((unsigned char)*C & 128)
892       // don't bother scanning the rest.
893       return SE_Fixed8;
894   }
895   if (isChar6)
896     return SE_Char6;
897   else
898     return SE_Fixed7;
899 }
900 
901 /// Emit top-level description of module, including target triple, inline asm,
902 /// descriptors for global variables, and function prototype info.
903 /// Returns the bit offset to backpatch with the location of the real VST.
904 void ModuleBitcodeWriter::writeModuleInfo() {
905   // Emit various pieces of data attached to a module.
906   if (!M.getTargetTriple().empty())
907     writeStringRecord(bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
908                       0 /*TODO*/);
909   const std::string &DL = M.getDataLayoutStr();
910   if (!DL.empty())
911     writeStringRecord(bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
912   if (!M.getModuleInlineAsm().empty())
913     writeStringRecord(bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
914                       0 /*TODO*/);
915 
916   // Emit information about sections and GC, computing how many there are. Also
917   // compute the maximum alignment value.
918   std::map<std::string, unsigned> SectionMap;
919   std::map<std::string, unsigned> GCMap;
920   unsigned MaxAlignment = 0;
921   unsigned MaxGlobalType = 0;
922   for (const GlobalValue &GV : M.globals()) {
923     MaxAlignment = std::max(MaxAlignment, GV.getAlignment());
924     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
925     if (GV.hasSection()) {
926       // Give section names unique ID's.
927       unsigned &Entry = SectionMap[GV.getSection()];
928       if (!Entry) {
929         writeStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
930                           0 /*TODO*/);
931         Entry = SectionMap.size();
932       }
933     }
934   }
935   for (const Function &F : M) {
936     MaxAlignment = std::max(MaxAlignment, F.getAlignment());
937     if (F.hasSection()) {
938       // Give section names unique ID's.
939       unsigned &Entry = SectionMap[F.getSection()];
940       if (!Entry) {
941         writeStringRecord(bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
942                           0 /*TODO*/);
943         Entry = SectionMap.size();
944       }
945     }
946     if (F.hasGC()) {
947       // Same for GC names.
948       unsigned &Entry = GCMap[F.getGC()];
949       if (!Entry) {
950         writeStringRecord(bitc::MODULE_CODE_GCNAME, F.getGC(), 0 /*TODO*/);
951         Entry = GCMap.size();
952       }
953     }
954   }
955 
956   // Emit abbrev for globals, now that we know # sections and max alignment.
957   unsigned SimpleGVarAbbrev = 0;
958   if (!M.global_empty()) {
959     // Add an abbrev for common globals with no visibility or thread localness.
960     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
961     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
962     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
963                               Log2_32_Ceil(MaxGlobalType+1)));
964     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
965                                                            //| explicitType << 1
966                                                            //| constant
967     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
968     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
969     if (MaxAlignment == 0)                                 // Alignment.
970       Abbv->Add(BitCodeAbbrevOp(0));
971     else {
972       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
973       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
974                                Log2_32_Ceil(MaxEncAlignment+1)));
975     }
976     if (SectionMap.empty())                                    // Section.
977       Abbv->Add(BitCodeAbbrevOp(0));
978     else
979       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
980                                Log2_32_Ceil(SectionMap.size()+1)));
981     // Don't bother emitting vis + thread local.
982     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
983   }
984 
985   // Emit the global variable information.
986   SmallVector<unsigned, 64> Vals;
987   for (const GlobalVariable &GV : M.globals()) {
988     unsigned AbbrevToUse = 0;
989 
990     // GLOBALVAR: [type, isconst, initid,
991     //             linkage, alignment, section, visibility, threadlocal,
992     //             unnamed_addr, externally_initialized, dllstorageclass,
993     //             comdat]
994     Vals.push_back(VE.getTypeID(GV.getValueType()));
995     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
996     Vals.push_back(GV.isDeclaration() ? 0 :
997                    (VE.getValueID(GV.getInitializer()) + 1));
998     Vals.push_back(getEncodedLinkage(GV));
999     Vals.push_back(Log2_32(GV.getAlignment())+1);
1000     Vals.push_back(GV.hasSection() ? SectionMap[GV.getSection()] : 0);
1001     if (GV.isThreadLocal() ||
1002         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1003         GV.hasUnnamedAddr() || GV.isExternallyInitialized() ||
1004         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1005         GV.hasComdat()) {
1006       Vals.push_back(getEncodedVisibility(GV));
1007       Vals.push_back(getEncodedThreadLocalMode(GV));
1008       Vals.push_back(GV.hasUnnamedAddr());
1009       Vals.push_back(GV.isExternallyInitialized());
1010       Vals.push_back(getEncodedDLLStorageClass(GV));
1011       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1012     } else {
1013       AbbrevToUse = SimpleGVarAbbrev;
1014     }
1015 
1016     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1017     Vals.clear();
1018   }
1019 
1020   // Emit the function proto information.
1021   for (const Function &F : M) {
1022     // FUNCTION:  [type, callingconv, isproto, linkage, paramattrs, alignment,
1023     //             section, visibility, gc, unnamed_addr, prologuedata,
1024     //             dllstorageclass, comdat, prefixdata, personalityfn]
1025     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1026     Vals.push_back(F.getCallingConv());
1027     Vals.push_back(F.isDeclaration());
1028     Vals.push_back(getEncodedLinkage(F));
1029     Vals.push_back(VE.getAttributeID(F.getAttributes()));
1030     Vals.push_back(Log2_32(F.getAlignment())+1);
1031     Vals.push_back(F.hasSection() ? SectionMap[F.getSection()] : 0);
1032     Vals.push_back(getEncodedVisibility(F));
1033     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1034     Vals.push_back(F.hasUnnamedAddr());
1035     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1036                                        : 0);
1037     Vals.push_back(getEncodedDLLStorageClass(F));
1038     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1039     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1040                                      : 0);
1041     Vals.push_back(
1042         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1043 
1044     unsigned AbbrevToUse = 0;
1045     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1046     Vals.clear();
1047   }
1048 
1049   // Emit the alias information.
1050   for (const GlobalAlias &A : M.aliases()) {
1051     // ALIAS: [alias type, aliasee val#, linkage, visibility]
1052     Vals.push_back(VE.getTypeID(A.getValueType()));
1053     Vals.push_back(A.getType()->getAddressSpace());
1054     Vals.push_back(VE.getValueID(A.getAliasee()));
1055     Vals.push_back(getEncodedLinkage(A));
1056     Vals.push_back(getEncodedVisibility(A));
1057     Vals.push_back(getEncodedDLLStorageClass(A));
1058     Vals.push_back(getEncodedThreadLocalMode(A));
1059     Vals.push_back(A.hasUnnamedAddr());
1060     unsigned AbbrevToUse = 0;
1061     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1062     Vals.clear();
1063   }
1064 
1065   // Emit the ifunc information.
1066   for (const GlobalIFunc &I : M.ifuncs()) {
1067     // IFUNC: [ifunc type, address space, resolver val#, linkage, visibility]
1068     Vals.push_back(VE.getTypeID(I.getValueType()));
1069     Vals.push_back(I.getType()->getAddressSpace());
1070     Vals.push_back(VE.getValueID(I.getResolver()));
1071     Vals.push_back(getEncodedLinkage(I));
1072     Vals.push_back(getEncodedVisibility(I));
1073     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1074     Vals.clear();
1075   }
1076 
1077   // Emit the module's source file name.
1078   {
1079     StringEncoding Bits = getStringEncoding(M.getSourceFileName().data(),
1080                                             M.getSourceFileName().size());
1081     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1082     if (Bits == SE_Char6)
1083       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1084     else if (Bits == SE_Fixed7)
1085       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1086 
1087     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1088     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1089     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1090     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1091     Abbv->Add(AbbrevOpToUse);
1092     unsigned FilenameAbbrev = Stream.EmitAbbrev(Abbv);
1093 
1094     for (const auto P : M.getSourceFileName())
1095       Vals.push_back((unsigned char)P);
1096 
1097     // Emit the finished record.
1098     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1099     Vals.clear();
1100   }
1101 
1102   // If we have a VST, write the VSTOFFSET record placeholder.
1103   if (M.getValueSymbolTable().empty())
1104     return;
1105   writeValueSymbolTableForwardDecl();
1106 }
1107 
1108 static uint64_t getOptimizationFlags(const Value *V) {
1109   uint64_t Flags = 0;
1110 
1111   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1112     if (OBO->hasNoSignedWrap())
1113       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1114     if (OBO->hasNoUnsignedWrap())
1115       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1116   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1117     if (PEO->isExact())
1118       Flags |= 1 << bitc::PEO_EXACT;
1119   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1120     if (FPMO->hasUnsafeAlgebra())
1121       Flags |= FastMathFlags::UnsafeAlgebra;
1122     if (FPMO->hasNoNaNs())
1123       Flags |= FastMathFlags::NoNaNs;
1124     if (FPMO->hasNoInfs())
1125       Flags |= FastMathFlags::NoInfs;
1126     if (FPMO->hasNoSignedZeros())
1127       Flags |= FastMathFlags::NoSignedZeros;
1128     if (FPMO->hasAllowReciprocal())
1129       Flags |= FastMathFlags::AllowReciprocal;
1130   }
1131 
1132   return Flags;
1133 }
1134 
1135 void ModuleBitcodeWriter::writeValueAsMetadata(
1136     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1137   // Mimic an MDNode with a value as one operand.
1138   Value *V = MD->getValue();
1139   Record.push_back(VE.getTypeID(V->getType()));
1140   Record.push_back(VE.getValueID(V));
1141   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1142   Record.clear();
1143 }
1144 
1145 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1146                                        SmallVectorImpl<uint64_t> &Record,
1147                                        unsigned Abbrev) {
1148   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1149     Metadata *MD = N->getOperand(i);
1150     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1151            "Unexpected function-local metadata");
1152     Record.push_back(VE.getMetadataOrNullID(MD));
1153   }
1154   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1155                                     : bitc::METADATA_NODE,
1156                     Record, Abbrev);
1157   Record.clear();
1158 }
1159 
1160 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1161   // Assume the column is usually under 128, and always output the inlined-at
1162   // location (it's never more expensive than building an array size 1).
1163   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1164   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1165   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1166   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1167   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1168   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1169   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1170   return Stream.EmitAbbrev(Abbv);
1171 }
1172 
1173 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1174                                           SmallVectorImpl<uint64_t> &Record,
1175                                           unsigned &Abbrev) {
1176   if (!Abbrev)
1177     Abbrev = createDILocationAbbrev();
1178 
1179   Record.push_back(N->isDistinct());
1180   Record.push_back(N->getLine());
1181   Record.push_back(N->getColumn());
1182   Record.push_back(VE.getMetadataID(N->getScope()));
1183   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1184 
1185   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1186   Record.clear();
1187 }
1188 
1189 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1190   // Assume the column is usually under 128, and always output the inlined-at
1191   // location (it's never more expensive than building an array size 1).
1192   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1193   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1194   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1195   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1196   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1197   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1198   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1199   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1200   return Stream.EmitAbbrev(Abbv);
1201 }
1202 
1203 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1204                                              SmallVectorImpl<uint64_t> &Record,
1205                                              unsigned &Abbrev) {
1206   if (!Abbrev)
1207     Abbrev = createGenericDINodeAbbrev();
1208 
1209   Record.push_back(N->isDistinct());
1210   Record.push_back(N->getTag());
1211   Record.push_back(0); // Per-tag version field; unused for now.
1212 
1213   for (auto &I : N->operands())
1214     Record.push_back(VE.getMetadataOrNullID(I));
1215 
1216   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1217   Record.clear();
1218 }
1219 
1220 static uint64_t rotateSign(int64_t I) {
1221   uint64_t U = I;
1222   return I < 0 ? ~(U << 1) : U << 1;
1223 }
1224 
1225 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1226                                           SmallVectorImpl<uint64_t> &Record,
1227                                           unsigned Abbrev) {
1228   Record.push_back(N->isDistinct());
1229   Record.push_back(N->getCount());
1230   Record.push_back(rotateSign(N->getLowerBound()));
1231 
1232   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1233   Record.clear();
1234 }
1235 
1236 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1237                                             SmallVectorImpl<uint64_t> &Record,
1238                                             unsigned Abbrev) {
1239   Record.push_back(N->isDistinct());
1240   Record.push_back(rotateSign(N->getValue()));
1241   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1242 
1243   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1244   Record.clear();
1245 }
1246 
1247 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1248                                            SmallVectorImpl<uint64_t> &Record,
1249                                            unsigned Abbrev) {
1250   Record.push_back(N->isDistinct());
1251   Record.push_back(N->getTag());
1252   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1253   Record.push_back(N->getSizeInBits());
1254   Record.push_back(N->getAlignInBits());
1255   Record.push_back(N->getEncoding());
1256 
1257   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1258   Record.clear();
1259 }
1260 
1261 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1262                                              SmallVectorImpl<uint64_t> &Record,
1263                                              unsigned Abbrev) {
1264   Record.push_back(N->isDistinct());
1265   Record.push_back(N->getTag());
1266   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1267   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1268   Record.push_back(N->getLine());
1269   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1270   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1271   Record.push_back(N->getSizeInBits());
1272   Record.push_back(N->getAlignInBits());
1273   Record.push_back(N->getOffsetInBits());
1274   Record.push_back(N->getFlags());
1275   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1276 
1277   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1278   Record.clear();
1279 }
1280 
1281 void ModuleBitcodeWriter::writeDICompositeType(
1282     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1283     unsigned Abbrev) {
1284   const unsigned IsNotUsedInOldTypeRef = 0x2;
1285   Record.push_back(IsNotUsedInOldTypeRef | N->isDistinct());
1286   Record.push_back(N->getTag());
1287   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1288   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1289   Record.push_back(N->getLine());
1290   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1291   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1292   Record.push_back(N->getSizeInBits());
1293   Record.push_back(N->getAlignInBits());
1294   Record.push_back(N->getOffsetInBits());
1295   Record.push_back(N->getFlags());
1296   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1297   Record.push_back(N->getRuntimeLang());
1298   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1299   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1300   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1301 
1302   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1303   Record.clear();
1304 }
1305 
1306 void ModuleBitcodeWriter::writeDISubroutineType(
1307     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1308     unsigned Abbrev) {
1309   const unsigned HasNoOldTypeRefs = 0x2;
1310   Record.push_back(HasNoOldTypeRefs | N->isDistinct());
1311   Record.push_back(N->getFlags());
1312   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1313 
1314   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1315   Record.clear();
1316 }
1317 
1318 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1319                                       SmallVectorImpl<uint64_t> &Record,
1320                                       unsigned Abbrev) {
1321   Record.push_back(N->isDistinct());
1322   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1323   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1324 
1325   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1326   Record.clear();
1327 }
1328 
1329 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1330                                              SmallVectorImpl<uint64_t> &Record,
1331                                              unsigned Abbrev) {
1332   assert(N->isDistinct() && "Expected distinct compile units");
1333   Record.push_back(/* IsDistinct */ true);
1334   Record.push_back(N->getSourceLanguage());
1335   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1336   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1337   Record.push_back(N->isOptimized());
1338   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1339   Record.push_back(N->getRuntimeVersion());
1340   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1341   Record.push_back(N->getEmissionKind());
1342   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1343   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1344   Record.push_back(/* subprograms */ 0);
1345   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1346   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1347   Record.push_back(N->getDWOId());
1348   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1349 
1350   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1351   Record.clear();
1352 }
1353 
1354 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1355                                             SmallVectorImpl<uint64_t> &Record,
1356                                             unsigned Abbrev) {
1357   Record.push_back(N->isDistinct());
1358   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1359   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1360   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1361   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1362   Record.push_back(N->getLine());
1363   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1364   Record.push_back(N->isLocalToUnit());
1365   Record.push_back(N->isDefinition());
1366   Record.push_back(N->getScopeLine());
1367   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1368   Record.push_back(N->getVirtuality());
1369   Record.push_back(N->getVirtualIndex());
1370   Record.push_back(N->getFlags());
1371   Record.push_back(N->isOptimized());
1372   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1373   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1374   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1375   Record.push_back(VE.getMetadataOrNullID(N->getVariables().get()));
1376 
1377   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1378   Record.clear();
1379 }
1380 
1381 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1382                                               SmallVectorImpl<uint64_t> &Record,
1383                                               unsigned Abbrev) {
1384   Record.push_back(N->isDistinct());
1385   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1386   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1387   Record.push_back(N->getLine());
1388   Record.push_back(N->getColumn());
1389 
1390   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1391   Record.clear();
1392 }
1393 
1394 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1395     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1396     unsigned Abbrev) {
1397   Record.push_back(N->isDistinct());
1398   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1399   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1400   Record.push_back(N->getDiscriminator());
1401 
1402   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1403   Record.clear();
1404 }
1405 
1406 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1407                                            SmallVectorImpl<uint64_t> &Record,
1408                                            unsigned Abbrev) {
1409   Record.push_back(N->isDistinct());
1410   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1411   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1412   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1413   Record.push_back(N->getLine());
1414 
1415   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1416   Record.clear();
1417 }
1418 
1419 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1420                                        SmallVectorImpl<uint64_t> &Record,
1421                                        unsigned Abbrev) {
1422   Record.push_back(N->isDistinct());
1423   Record.push_back(N->getMacinfoType());
1424   Record.push_back(N->getLine());
1425   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1426   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1427 
1428   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1429   Record.clear();
1430 }
1431 
1432 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1433                                            SmallVectorImpl<uint64_t> &Record,
1434                                            unsigned Abbrev) {
1435   Record.push_back(N->isDistinct());
1436   Record.push_back(N->getMacinfoType());
1437   Record.push_back(N->getLine());
1438   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1439   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1440 
1441   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1442   Record.clear();
1443 }
1444 
1445 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1446                                         SmallVectorImpl<uint64_t> &Record,
1447                                         unsigned Abbrev) {
1448   Record.push_back(N->isDistinct());
1449   for (auto &I : N->operands())
1450     Record.push_back(VE.getMetadataOrNullID(I));
1451 
1452   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1453   Record.clear();
1454 }
1455 
1456 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1457     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1458     unsigned Abbrev) {
1459   Record.push_back(N->isDistinct());
1460   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1461   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1462 
1463   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1464   Record.clear();
1465 }
1466 
1467 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1468     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1469     unsigned Abbrev) {
1470   Record.push_back(N->isDistinct());
1471   Record.push_back(N->getTag());
1472   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1473   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1474   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1475 
1476   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1477   Record.clear();
1478 }
1479 
1480 void ModuleBitcodeWriter::writeDIGlobalVariable(
1481     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1482     unsigned Abbrev) {
1483   Record.push_back(N->isDistinct());
1484   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1485   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1486   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1487   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1488   Record.push_back(N->getLine());
1489   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1490   Record.push_back(N->isLocalToUnit());
1491   Record.push_back(N->isDefinition());
1492   Record.push_back(VE.getMetadataOrNullID(N->getRawVariable()));
1493   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1494 
1495   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1496   Record.clear();
1497 }
1498 
1499 void ModuleBitcodeWriter::writeDILocalVariable(
1500     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
1501     unsigned Abbrev) {
1502   Record.push_back(N->isDistinct());
1503   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1504   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1505   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1506   Record.push_back(N->getLine());
1507   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1508   Record.push_back(N->getArg());
1509   Record.push_back(N->getFlags());
1510 
1511   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1512   Record.clear();
1513 }
1514 
1515 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
1516                                             SmallVectorImpl<uint64_t> &Record,
1517                                             unsigned Abbrev) {
1518   Record.reserve(N->getElements().size() + 1);
1519 
1520   Record.push_back(N->isDistinct());
1521   Record.append(N->elements_begin(), N->elements_end());
1522 
1523   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
1524   Record.clear();
1525 }
1526 
1527 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
1528                                               SmallVectorImpl<uint64_t> &Record,
1529                                               unsigned Abbrev) {
1530   Record.push_back(N->isDistinct());
1531   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1532   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1533   Record.push_back(N->getLine());
1534   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
1535   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
1536   Record.push_back(N->getAttributes());
1537   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1538 
1539   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
1540   Record.clear();
1541 }
1542 
1543 void ModuleBitcodeWriter::writeDIImportedEntity(
1544     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
1545     unsigned Abbrev) {
1546   Record.push_back(N->isDistinct());
1547   Record.push_back(N->getTag());
1548   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1549   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
1550   Record.push_back(N->getLine());
1551   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1552 
1553   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
1554   Record.clear();
1555 }
1556 
1557 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
1558   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1559   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
1560   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1561   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1562   return Stream.EmitAbbrev(Abbv);
1563 }
1564 
1565 void ModuleBitcodeWriter::writeNamedMetadata(
1566     SmallVectorImpl<uint64_t> &Record) {
1567   if (M.named_metadata_empty())
1568     return;
1569 
1570   unsigned Abbrev = createNamedMetadataAbbrev();
1571   for (const NamedMDNode &NMD : M.named_metadata()) {
1572     // Write name.
1573     StringRef Str = NMD.getName();
1574     Record.append(Str.bytes_begin(), Str.bytes_end());
1575     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
1576     Record.clear();
1577 
1578     // Write named metadata operands.
1579     for (const MDNode *N : NMD.operands())
1580       Record.push_back(VE.getMetadataID(N));
1581     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
1582     Record.clear();
1583   }
1584 }
1585 
1586 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
1587   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1588   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
1589   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
1590   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
1591   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
1592   return Stream.EmitAbbrev(Abbv);
1593 }
1594 
1595 /// Write out a record for MDString.
1596 ///
1597 /// All the metadata strings in a metadata block are emitted in a single
1598 /// record.  The sizes and strings themselves are shoved into a blob.
1599 void ModuleBitcodeWriter::writeMetadataStrings(
1600     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
1601   if (Strings.empty())
1602     return;
1603 
1604   // Start the record with the number of strings.
1605   Record.push_back(bitc::METADATA_STRINGS);
1606   Record.push_back(Strings.size());
1607 
1608   // Emit the sizes of the strings in the blob.
1609   SmallString<256> Blob;
1610   {
1611     BitstreamWriter W(Blob);
1612     for (const Metadata *MD : Strings)
1613       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
1614     W.FlushToWord();
1615   }
1616 
1617   // Add the offset to the strings to the record.
1618   Record.push_back(Blob.size());
1619 
1620   // Add the strings to the blob.
1621   for (const Metadata *MD : Strings)
1622     Blob.append(cast<MDString>(MD)->getString());
1623 
1624   // Emit the final record.
1625   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
1626   Record.clear();
1627 }
1628 
1629 void ModuleBitcodeWriter::writeMetadataRecords(
1630     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record) {
1631   if (MDs.empty())
1632     return;
1633 
1634   // Initialize MDNode abbreviations.
1635 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
1636 #include "llvm/IR/Metadata.def"
1637 
1638   for (const Metadata *MD : MDs) {
1639     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
1640       assert(N->isResolved() && "Expected forward references to be resolved");
1641 
1642       switch (N->getMetadataID()) {
1643       default:
1644         llvm_unreachable("Invalid MDNode subclass");
1645 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
1646   case Metadata::CLASS##Kind:                                                  \
1647     write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                       \
1648     continue;
1649 #include "llvm/IR/Metadata.def"
1650       }
1651     }
1652     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
1653   }
1654 }
1655 
1656 void ModuleBitcodeWriter::writeModuleMetadata() {
1657   if (!VE.hasMDs() && M.named_metadata_empty())
1658     return;
1659 
1660   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1661   SmallVector<uint64_t, 64> Record;
1662   writeMetadataStrings(VE.getMDStrings(), Record);
1663   writeMetadataRecords(VE.getNonMDStrings(), Record);
1664   writeNamedMetadata(Record);
1665   Stream.ExitBlock();
1666 }
1667 
1668 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
1669   if (!VE.hasMDs())
1670     return;
1671 
1672   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1673   SmallVector<uint64_t, 64> Record;
1674   writeMetadataStrings(VE.getMDStrings(), Record);
1675   writeMetadataRecords(VE.getNonMDStrings(), Record);
1676   Stream.ExitBlock();
1677 }
1678 
1679 void ModuleBitcodeWriter::writeMetadataAttachment(const Function &F) {
1680   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
1681 
1682   SmallVector<uint64_t, 64> Record;
1683 
1684   // Write metadata attachments
1685   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
1686   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
1687   F.getAllMetadata(MDs);
1688   if (!MDs.empty()) {
1689     for (const auto &I : MDs) {
1690       Record.push_back(I.first);
1691       Record.push_back(VE.getMetadataID(I.second));
1692     }
1693     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1694     Record.clear();
1695   }
1696 
1697   for (const BasicBlock &BB : F)
1698     for (const Instruction &I : BB) {
1699       MDs.clear();
1700       I.getAllMetadataOtherThanDebugLoc(MDs);
1701 
1702       // If no metadata, ignore instruction.
1703       if (MDs.empty()) continue;
1704 
1705       Record.push_back(VE.getInstructionID(&I));
1706 
1707       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1708         Record.push_back(MDs[i].first);
1709         Record.push_back(VE.getMetadataID(MDs[i].second));
1710       }
1711       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1712       Record.clear();
1713     }
1714 
1715   Stream.ExitBlock();
1716 }
1717 
1718 void ModuleBitcodeWriter::writeModuleMetadataStore() {
1719   SmallVector<uint64_t, 64> Record;
1720 
1721   // Write metadata kinds
1722   // METADATA_KIND - [n x [id, name]]
1723   SmallVector<StringRef, 8> Names;
1724   M.getMDKindNames(Names);
1725 
1726   if (Names.empty()) return;
1727 
1728   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
1729 
1730   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
1731     Record.push_back(MDKindID);
1732     StringRef KName = Names[MDKindID];
1733     Record.append(KName.begin(), KName.end());
1734 
1735     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
1736     Record.clear();
1737   }
1738 
1739   Stream.ExitBlock();
1740 }
1741 
1742 void ModuleBitcodeWriter::writeOperandBundleTags() {
1743   // Write metadata kinds
1744   //
1745   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
1746   //
1747   // OPERAND_BUNDLE_TAG - [strchr x N]
1748 
1749   SmallVector<StringRef, 8> Tags;
1750   M.getOperandBundleTags(Tags);
1751 
1752   if (Tags.empty())
1753     return;
1754 
1755   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
1756 
1757   SmallVector<uint64_t, 64> Record;
1758 
1759   for (auto Tag : Tags) {
1760     Record.append(Tag.begin(), Tag.end());
1761 
1762     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
1763     Record.clear();
1764   }
1765 
1766   Stream.ExitBlock();
1767 }
1768 
1769 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1770   if ((int64_t)V >= 0)
1771     Vals.push_back(V << 1);
1772   else
1773     Vals.push_back((-V << 1) | 1);
1774 }
1775 
1776 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
1777                                          bool isGlobal) {
1778   if (FirstVal == LastVal) return;
1779 
1780   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
1781 
1782   unsigned AggregateAbbrev = 0;
1783   unsigned String8Abbrev = 0;
1784   unsigned CString7Abbrev = 0;
1785   unsigned CString6Abbrev = 0;
1786   // If this is a constant pool for the module, emit module-specific abbrevs.
1787   if (isGlobal) {
1788     // Abbrev for CST_CODE_AGGREGATE.
1789     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1790     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
1791     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1792     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
1793     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
1794 
1795     // Abbrev for CST_CODE_STRING.
1796     Abbv = new BitCodeAbbrev();
1797     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
1798     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1799     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1800     String8Abbrev = Stream.EmitAbbrev(Abbv);
1801     // Abbrev for CST_CODE_CSTRING.
1802     Abbv = new BitCodeAbbrev();
1803     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1804     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1805     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1806     CString7Abbrev = Stream.EmitAbbrev(Abbv);
1807     // Abbrev for CST_CODE_CSTRING.
1808     Abbv = new BitCodeAbbrev();
1809     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1810     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1811     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1812     CString6Abbrev = Stream.EmitAbbrev(Abbv);
1813   }
1814 
1815   SmallVector<uint64_t, 64> Record;
1816 
1817   const ValueEnumerator::ValueList &Vals = VE.getValues();
1818   Type *LastTy = nullptr;
1819   for (unsigned i = FirstVal; i != LastVal; ++i) {
1820     const Value *V = Vals[i].first;
1821     // If we need to switch types, do so now.
1822     if (V->getType() != LastTy) {
1823       LastTy = V->getType();
1824       Record.push_back(VE.getTypeID(LastTy));
1825       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
1826                         CONSTANTS_SETTYPE_ABBREV);
1827       Record.clear();
1828     }
1829 
1830     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
1831       Record.push_back(unsigned(IA->hasSideEffects()) |
1832                        unsigned(IA->isAlignStack()) << 1 |
1833                        unsigned(IA->getDialect()&1) << 2);
1834 
1835       // Add the asm string.
1836       const std::string &AsmStr = IA->getAsmString();
1837       Record.push_back(AsmStr.size());
1838       Record.append(AsmStr.begin(), AsmStr.end());
1839 
1840       // Add the constraint string.
1841       const std::string &ConstraintStr = IA->getConstraintString();
1842       Record.push_back(ConstraintStr.size());
1843       Record.append(ConstraintStr.begin(), ConstraintStr.end());
1844       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
1845       Record.clear();
1846       continue;
1847     }
1848     const Constant *C = cast<Constant>(V);
1849     unsigned Code = -1U;
1850     unsigned AbbrevToUse = 0;
1851     if (C->isNullValue()) {
1852       Code = bitc::CST_CODE_NULL;
1853     } else if (isa<UndefValue>(C)) {
1854       Code = bitc::CST_CODE_UNDEF;
1855     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
1856       if (IV->getBitWidth() <= 64) {
1857         uint64_t V = IV->getSExtValue();
1858         emitSignedInt64(Record, V);
1859         Code = bitc::CST_CODE_INTEGER;
1860         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
1861       } else {                             // Wide integers, > 64 bits in size.
1862         // We have an arbitrary precision integer value to write whose
1863         // bit width is > 64. However, in canonical unsigned integer
1864         // format it is likely that the high bits are going to be zero.
1865         // So, we only write the number of active words.
1866         unsigned NWords = IV->getValue().getActiveWords();
1867         const uint64_t *RawWords = IV->getValue().getRawData();
1868         for (unsigned i = 0; i != NWords; ++i) {
1869           emitSignedInt64(Record, RawWords[i]);
1870         }
1871         Code = bitc::CST_CODE_WIDE_INTEGER;
1872       }
1873     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
1874       Code = bitc::CST_CODE_FLOAT;
1875       Type *Ty = CFP->getType();
1876       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
1877         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
1878       } else if (Ty->isX86_FP80Ty()) {
1879         // api needed to prevent premature destruction
1880         // bits are not in the same order as a normal i80 APInt, compensate.
1881         APInt api = CFP->getValueAPF().bitcastToAPInt();
1882         const uint64_t *p = api.getRawData();
1883         Record.push_back((p[1] << 48) | (p[0] >> 16));
1884         Record.push_back(p[0] & 0xffffLL);
1885       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
1886         APInt api = CFP->getValueAPF().bitcastToAPInt();
1887         const uint64_t *p = api.getRawData();
1888         Record.push_back(p[0]);
1889         Record.push_back(p[1]);
1890       } else {
1891         assert (0 && "Unknown FP type!");
1892       }
1893     } else if (isa<ConstantDataSequential>(C) &&
1894                cast<ConstantDataSequential>(C)->isString()) {
1895       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
1896       // Emit constant strings specially.
1897       unsigned NumElts = Str->getNumElements();
1898       // If this is a null-terminated string, use the denser CSTRING encoding.
1899       if (Str->isCString()) {
1900         Code = bitc::CST_CODE_CSTRING;
1901         --NumElts;  // Don't encode the null, which isn't allowed by char6.
1902       } else {
1903         Code = bitc::CST_CODE_STRING;
1904         AbbrevToUse = String8Abbrev;
1905       }
1906       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
1907       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
1908       for (unsigned i = 0; i != NumElts; ++i) {
1909         unsigned char V = Str->getElementAsInteger(i);
1910         Record.push_back(V);
1911         isCStr7 &= (V & 128) == 0;
1912         if (isCStrChar6)
1913           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
1914       }
1915 
1916       if (isCStrChar6)
1917         AbbrevToUse = CString6Abbrev;
1918       else if (isCStr7)
1919         AbbrevToUse = CString7Abbrev;
1920     } else if (const ConstantDataSequential *CDS =
1921                   dyn_cast<ConstantDataSequential>(C)) {
1922       Code = bitc::CST_CODE_DATA;
1923       Type *EltTy = CDS->getType()->getElementType();
1924       if (isa<IntegerType>(EltTy)) {
1925         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
1926           Record.push_back(CDS->getElementAsInteger(i));
1927       } else {
1928         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
1929           Record.push_back(
1930               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
1931       }
1932     } else if (isa<ConstantAggregate>(C)) {
1933       Code = bitc::CST_CODE_AGGREGATE;
1934       for (const Value *Op : C->operands())
1935         Record.push_back(VE.getValueID(Op));
1936       AbbrevToUse = AggregateAbbrev;
1937     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
1938       switch (CE->getOpcode()) {
1939       default:
1940         if (Instruction::isCast(CE->getOpcode())) {
1941           Code = bitc::CST_CODE_CE_CAST;
1942           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
1943           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1944           Record.push_back(VE.getValueID(C->getOperand(0)));
1945           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
1946         } else {
1947           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
1948           Code = bitc::CST_CODE_CE_BINOP;
1949           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
1950           Record.push_back(VE.getValueID(C->getOperand(0)));
1951           Record.push_back(VE.getValueID(C->getOperand(1)));
1952           uint64_t Flags = getOptimizationFlags(CE);
1953           if (Flags != 0)
1954             Record.push_back(Flags);
1955         }
1956         break;
1957       case Instruction::GetElementPtr: {
1958         Code = bitc::CST_CODE_CE_GEP;
1959         const auto *GO = cast<GEPOperator>(C);
1960         if (GO->isInBounds())
1961           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
1962         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
1963         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
1964           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
1965           Record.push_back(VE.getValueID(C->getOperand(i)));
1966         }
1967         break;
1968       }
1969       case Instruction::Select:
1970         Code = bitc::CST_CODE_CE_SELECT;
1971         Record.push_back(VE.getValueID(C->getOperand(0)));
1972         Record.push_back(VE.getValueID(C->getOperand(1)));
1973         Record.push_back(VE.getValueID(C->getOperand(2)));
1974         break;
1975       case Instruction::ExtractElement:
1976         Code = bitc::CST_CODE_CE_EXTRACTELT;
1977         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1978         Record.push_back(VE.getValueID(C->getOperand(0)));
1979         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
1980         Record.push_back(VE.getValueID(C->getOperand(1)));
1981         break;
1982       case Instruction::InsertElement:
1983         Code = bitc::CST_CODE_CE_INSERTELT;
1984         Record.push_back(VE.getValueID(C->getOperand(0)));
1985         Record.push_back(VE.getValueID(C->getOperand(1)));
1986         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
1987         Record.push_back(VE.getValueID(C->getOperand(2)));
1988         break;
1989       case Instruction::ShuffleVector:
1990         // If the return type and argument types are the same, this is a
1991         // standard shufflevector instruction.  If the types are different,
1992         // then the shuffle is widening or truncating the input vectors, and
1993         // the argument type must also be encoded.
1994         if (C->getType() == C->getOperand(0)->getType()) {
1995           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
1996         } else {
1997           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
1998           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1999         }
2000         Record.push_back(VE.getValueID(C->getOperand(0)));
2001         Record.push_back(VE.getValueID(C->getOperand(1)));
2002         Record.push_back(VE.getValueID(C->getOperand(2)));
2003         break;
2004       case Instruction::ICmp:
2005       case Instruction::FCmp:
2006         Code = bitc::CST_CODE_CE_CMP;
2007         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2008         Record.push_back(VE.getValueID(C->getOperand(0)));
2009         Record.push_back(VE.getValueID(C->getOperand(1)));
2010         Record.push_back(CE->getPredicate());
2011         break;
2012       }
2013     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2014       Code = bitc::CST_CODE_BLOCKADDRESS;
2015       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2016       Record.push_back(VE.getValueID(BA->getFunction()));
2017       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2018     } else {
2019 #ifndef NDEBUG
2020       C->dump();
2021 #endif
2022       llvm_unreachable("Unknown constant!");
2023     }
2024     Stream.EmitRecord(Code, Record, AbbrevToUse);
2025     Record.clear();
2026   }
2027 
2028   Stream.ExitBlock();
2029 }
2030 
2031 void ModuleBitcodeWriter::writeModuleConstants() {
2032   const ValueEnumerator::ValueList &Vals = VE.getValues();
2033 
2034   // Find the first constant to emit, which is the first non-globalvalue value.
2035   // We know globalvalues have been emitted by WriteModuleInfo.
2036   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2037     if (!isa<GlobalValue>(Vals[i].first)) {
2038       writeConstants(i, Vals.size(), true);
2039       return;
2040     }
2041   }
2042 }
2043 
2044 /// pushValueAndType - The file has to encode both the value and type id for
2045 /// many values, because we need to know what type to create for forward
2046 /// references.  However, most operands are not forward references, so this type
2047 /// field is not needed.
2048 ///
2049 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2050 /// instruction ID, then it is a forward reference, and it also includes the
2051 /// type ID.  The value ID that is written is encoded relative to the InstID.
2052 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2053                                            SmallVectorImpl<unsigned> &Vals) {
2054   unsigned ValID = VE.getValueID(V);
2055   // Make encoding relative to the InstID.
2056   Vals.push_back(InstID - ValID);
2057   if (ValID >= InstID) {
2058     Vals.push_back(VE.getTypeID(V->getType()));
2059     return true;
2060   }
2061   return false;
2062 }
2063 
2064 void ModuleBitcodeWriter::writeOperandBundles(ImmutableCallSite CS,
2065                                               unsigned InstID) {
2066   SmallVector<unsigned, 64> Record;
2067   LLVMContext &C = CS.getInstruction()->getContext();
2068 
2069   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2070     const auto &Bundle = CS.getOperandBundleAt(i);
2071     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2072 
2073     for (auto &Input : Bundle.Inputs)
2074       pushValueAndType(Input, InstID, Record);
2075 
2076     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2077     Record.clear();
2078   }
2079 }
2080 
2081 /// pushValue - Like pushValueAndType, but where the type of the value is
2082 /// omitted (perhaps it was already encoded in an earlier operand).
2083 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2084                                     SmallVectorImpl<unsigned> &Vals) {
2085   unsigned ValID = VE.getValueID(V);
2086   Vals.push_back(InstID - ValID);
2087 }
2088 
2089 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2090                                           SmallVectorImpl<uint64_t> &Vals) {
2091   unsigned ValID = VE.getValueID(V);
2092   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2093   emitSignedInt64(Vals, diff);
2094 }
2095 
2096 /// WriteInstruction - Emit an instruction to the specified stream.
2097 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2098                                            unsigned InstID,
2099                                            SmallVectorImpl<unsigned> &Vals) {
2100   unsigned Code = 0;
2101   unsigned AbbrevToUse = 0;
2102   VE.setInstructionID(&I);
2103   switch (I.getOpcode()) {
2104   default:
2105     if (Instruction::isCast(I.getOpcode())) {
2106       Code = bitc::FUNC_CODE_INST_CAST;
2107       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2108         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2109       Vals.push_back(VE.getTypeID(I.getType()));
2110       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2111     } else {
2112       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2113       Code = bitc::FUNC_CODE_INST_BINOP;
2114       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2115         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2116       pushValue(I.getOperand(1), InstID, Vals);
2117       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2118       uint64_t Flags = getOptimizationFlags(&I);
2119       if (Flags != 0) {
2120         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2121           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2122         Vals.push_back(Flags);
2123       }
2124     }
2125     break;
2126 
2127   case Instruction::GetElementPtr: {
2128     Code = bitc::FUNC_CODE_INST_GEP;
2129     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2130     auto &GEPInst = cast<GetElementPtrInst>(I);
2131     Vals.push_back(GEPInst.isInBounds());
2132     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2133     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2134       pushValueAndType(I.getOperand(i), InstID, Vals);
2135     break;
2136   }
2137   case Instruction::ExtractValue: {
2138     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2139     pushValueAndType(I.getOperand(0), InstID, Vals);
2140     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2141     Vals.append(EVI->idx_begin(), EVI->idx_end());
2142     break;
2143   }
2144   case Instruction::InsertValue: {
2145     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2146     pushValueAndType(I.getOperand(0), InstID, Vals);
2147     pushValueAndType(I.getOperand(1), InstID, Vals);
2148     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2149     Vals.append(IVI->idx_begin(), IVI->idx_end());
2150     break;
2151   }
2152   case Instruction::Select:
2153     Code = bitc::FUNC_CODE_INST_VSELECT;
2154     pushValueAndType(I.getOperand(1), InstID, Vals);
2155     pushValue(I.getOperand(2), InstID, Vals);
2156     pushValueAndType(I.getOperand(0), InstID, Vals);
2157     break;
2158   case Instruction::ExtractElement:
2159     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2160     pushValueAndType(I.getOperand(0), InstID, Vals);
2161     pushValueAndType(I.getOperand(1), InstID, Vals);
2162     break;
2163   case Instruction::InsertElement:
2164     Code = bitc::FUNC_CODE_INST_INSERTELT;
2165     pushValueAndType(I.getOperand(0), InstID, Vals);
2166     pushValue(I.getOperand(1), InstID, Vals);
2167     pushValueAndType(I.getOperand(2), InstID, Vals);
2168     break;
2169   case Instruction::ShuffleVector:
2170     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2171     pushValueAndType(I.getOperand(0), InstID, Vals);
2172     pushValue(I.getOperand(1), InstID, Vals);
2173     pushValue(I.getOperand(2), InstID, Vals);
2174     break;
2175   case Instruction::ICmp:
2176   case Instruction::FCmp: {
2177     // compare returning Int1Ty or vector of Int1Ty
2178     Code = bitc::FUNC_CODE_INST_CMP2;
2179     pushValueAndType(I.getOperand(0), InstID, Vals);
2180     pushValue(I.getOperand(1), InstID, Vals);
2181     Vals.push_back(cast<CmpInst>(I).getPredicate());
2182     uint64_t Flags = getOptimizationFlags(&I);
2183     if (Flags != 0)
2184       Vals.push_back(Flags);
2185     break;
2186   }
2187 
2188   case Instruction::Ret:
2189     {
2190       Code = bitc::FUNC_CODE_INST_RET;
2191       unsigned NumOperands = I.getNumOperands();
2192       if (NumOperands == 0)
2193         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2194       else if (NumOperands == 1) {
2195         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2196           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2197       } else {
2198         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2199           pushValueAndType(I.getOperand(i), InstID, Vals);
2200       }
2201     }
2202     break;
2203   case Instruction::Br:
2204     {
2205       Code = bitc::FUNC_CODE_INST_BR;
2206       const BranchInst &II = cast<BranchInst>(I);
2207       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2208       if (II.isConditional()) {
2209         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2210         pushValue(II.getCondition(), InstID, Vals);
2211       }
2212     }
2213     break;
2214   case Instruction::Switch:
2215     {
2216       Code = bitc::FUNC_CODE_INST_SWITCH;
2217       const SwitchInst &SI = cast<SwitchInst>(I);
2218       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2219       pushValue(SI.getCondition(), InstID, Vals);
2220       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2221       for (SwitchInst::ConstCaseIt Case : SI.cases()) {
2222         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2223         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2224       }
2225     }
2226     break;
2227   case Instruction::IndirectBr:
2228     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2229     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2230     // Encode the address operand as relative, but not the basic blocks.
2231     pushValue(I.getOperand(0), InstID, Vals);
2232     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2233       Vals.push_back(VE.getValueID(I.getOperand(i)));
2234     break;
2235 
2236   case Instruction::Invoke: {
2237     const InvokeInst *II = cast<InvokeInst>(&I);
2238     const Value *Callee = II->getCalledValue();
2239     FunctionType *FTy = II->getFunctionType();
2240 
2241     if (II->hasOperandBundles())
2242       writeOperandBundles(II, InstID);
2243 
2244     Code = bitc::FUNC_CODE_INST_INVOKE;
2245 
2246     Vals.push_back(VE.getAttributeID(II->getAttributes()));
2247     Vals.push_back(II->getCallingConv() | 1 << 13);
2248     Vals.push_back(VE.getValueID(II->getNormalDest()));
2249     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2250     Vals.push_back(VE.getTypeID(FTy));
2251     pushValueAndType(Callee, InstID, Vals);
2252 
2253     // Emit value #'s for the fixed parameters.
2254     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2255       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2256 
2257     // Emit type/value pairs for varargs params.
2258     if (FTy->isVarArg()) {
2259       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
2260            i != e; ++i)
2261         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2262     }
2263     break;
2264   }
2265   case Instruction::Resume:
2266     Code = bitc::FUNC_CODE_INST_RESUME;
2267     pushValueAndType(I.getOperand(0), InstID, Vals);
2268     break;
2269   case Instruction::CleanupRet: {
2270     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2271     const auto &CRI = cast<CleanupReturnInst>(I);
2272     pushValue(CRI.getCleanupPad(), InstID, Vals);
2273     if (CRI.hasUnwindDest())
2274       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2275     break;
2276   }
2277   case Instruction::CatchRet: {
2278     Code = bitc::FUNC_CODE_INST_CATCHRET;
2279     const auto &CRI = cast<CatchReturnInst>(I);
2280     pushValue(CRI.getCatchPad(), InstID, Vals);
2281     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2282     break;
2283   }
2284   case Instruction::CleanupPad:
2285   case Instruction::CatchPad: {
2286     const auto &FuncletPad = cast<FuncletPadInst>(I);
2287     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2288                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2289     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2290 
2291     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2292     Vals.push_back(NumArgOperands);
2293     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2294       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2295     break;
2296   }
2297   case Instruction::CatchSwitch: {
2298     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2299     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2300 
2301     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2302 
2303     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2304     Vals.push_back(NumHandlers);
2305     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2306       Vals.push_back(VE.getValueID(CatchPadBB));
2307 
2308     if (CatchSwitch.hasUnwindDest())
2309       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
2310     break;
2311   }
2312   case Instruction::Unreachable:
2313     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
2314     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
2315     break;
2316 
2317   case Instruction::PHI: {
2318     const PHINode &PN = cast<PHINode>(I);
2319     Code = bitc::FUNC_CODE_INST_PHI;
2320     // With the newer instruction encoding, forward references could give
2321     // negative valued IDs.  This is most common for PHIs, so we use
2322     // signed VBRs.
2323     SmallVector<uint64_t, 128> Vals64;
2324     Vals64.push_back(VE.getTypeID(PN.getType()));
2325     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
2326       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
2327       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
2328     }
2329     // Emit a Vals64 vector and exit.
2330     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
2331     Vals64.clear();
2332     return;
2333   }
2334 
2335   case Instruction::LandingPad: {
2336     const LandingPadInst &LP = cast<LandingPadInst>(I);
2337     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
2338     Vals.push_back(VE.getTypeID(LP.getType()));
2339     Vals.push_back(LP.isCleanup());
2340     Vals.push_back(LP.getNumClauses());
2341     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
2342       if (LP.isCatch(I))
2343         Vals.push_back(LandingPadInst::Catch);
2344       else
2345         Vals.push_back(LandingPadInst::Filter);
2346       pushValueAndType(LP.getClause(I), InstID, Vals);
2347     }
2348     break;
2349   }
2350 
2351   case Instruction::Alloca: {
2352     Code = bitc::FUNC_CODE_INST_ALLOCA;
2353     const AllocaInst &AI = cast<AllocaInst>(I);
2354     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
2355     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2356     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
2357     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
2358     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
2359            "not enough bits for maximum alignment");
2360     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
2361     AlignRecord |= AI.isUsedWithInAlloca() << 5;
2362     AlignRecord |= 1 << 6;
2363     AlignRecord |= AI.isSwiftError() << 7;
2364     Vals.push_back(AlignRecord);
2365     break;
2366   }
2367 
2368   case Instruction::Load:
2369     if (cast<LoadInst>(I).isAtomic()) {
2370       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
2371       pushValueAndType(I.getOperand(0), InstID, Vals);
2372     } else {
2373       Code = bitc::FUNC_CODE_INST_LOAD;
2374       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
2375         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
2376     }
2377     Vals.push_back(VE.getTypeID(I.getType()));
2378     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
2379     Vals.push_back(cast<LoadInst>(I).isVolatile());
2380     if (cast<LoadInst>(I).isAtomic()) {
2381       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
2382       Vals.push_back(getEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
2383     }
2384     break;
2385   case Instruction::Store:
2386     if (cast<StoreInst>(I).isAtomic())
2387       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
2388     else
2389       Code = bitc::FUNC_CODE_INST_STORE;
2390     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
2391     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
2392     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
2393     Vals.push_back(cast<StoreInst>(I).isVolatile());
2394     if (cast<StoreInst>(I).isAtomic()) {
2395       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
2396       Vals.push_back(getEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
2397     }
2398     break;
2399   case Instruction::AtomicCmpXchg:
2400     Code = bitc::FUNC_CODE_INST_CMPXCHG;
2401     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
2402     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
2403     pushValue(I.getOperand(2), InstID, Vals);        // newval.
2404     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
2405     Vals.push_back(
2406         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
2407     Vals.push_back(
2408         getEncodedSynchScope(cast<AtomicCmpXchgInst>(I).getSynchScope()));
2409     Vals.push_back(
2410         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
2411     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
2412     break;
2413   case Instruction::AtomicRMW:
2414     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
2415     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
2416     pushValue(I.getOperand(1), InstID, Vals);        // val.
2417     Vals.push_back(
2418         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
2419     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
2420     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
2421     Vals.push_back(
2422         getEncodedSynchScope(cast<AtomicRMWInst>(I).getSynchScope()));
2423     break;
2424   case Instruction::Fence:
2425     Code = bitc::FUNC_CODE_INST_FENCE;
2426     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
2427     Vals.push_back(getEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
2428     break;
2429   case Instruction::Call: {
2430     const CallInst &CI = cast<CallInst>(I);
2431     FunctionType *FTy = CI.getFunctionType();
2432 
2433     if (CI.hasOperandBundles())
2434       writeOperandBundles(&CI, InstID);
2435 
2436     Code = bitc::FUNC_CODE_INST_CALL;
2437 
2438     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
2439 
2440     unsigned Flags = getOptimizationFlags(&I);
2441     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
2442                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
2443                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
2444                    1 << bitc::CALL_EXPLICIT_TYPE |
2445                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
2446                    unsigned(Flags != 0) << bitc::CALL_FMF);
2447     if (Flags != 0)
2448       Vals.push_back(Flags);
2449 
2450     Vals.push_back(VE.getTypeID(FTy));
2451     pushValueAndType(CI.getCalledValue(), InstID, Vals); // Callee
2452 
2453     // Emit value #'s for the fixed parameters.
2454     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
2455       // Check for labels (can happen with asm labels).
2456       if (FTy->getParamType(i)->isLabelTy())
2457         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
2458       else
2459         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
2460     }
2461 
2462     // Emit type/value pairs for varargs params.
2463     if (FTy->isVarArg()) {
2464       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
2465            i != e; ++i)
2466         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
2467     }
2468     break;
2469   }
2470   case Instruction::VAArg:
2471     Code = bitc::FUNC_CODE_INST_VAARG;
2472     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
2473     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
2474     Vals.push_back(VE.getTypeID(I.getType())); // restype.
2475     break;
2476   }
2477 
2478   Stream.EmitRecord(Code, Vals, AbbrevToUse);
2479   Vals.clear();
2480 }
2481 
2482 /// Emit names for globals/functions etc. \p IsModuleLevel is true when
2483 /// we are writing the module-level VST, where we are including a function
2484 /// bitcode index and need to backpatch the VST forward declaration record.
2485 void ModuleBitcodeWriter::writeValueSymbolTable(
2486     const ValueSymbolTable &VST, bool IsModuleLevel,
2487     DenseMap<const Function *, uint64_t> *FunctionToBitcodeIndex) {
2488   if (VST.empty()) {
2489     // writeValueSymbolTableForwardDecl should have returned early as
2490     // well. Ensure this handling remains in sync by asserting that
2491     // the placeholder offset is not set.
2492     assert(!IsModuleLevel || !hasVSTOffsetPlaceholder());
2493     return;
2494   }
2495 
2496   if (IsModuleLevel && hasVSTOffsetPlaceholder()) {
2497     // Get the offset of the VST we are writing, and backpatch it into
2498     // the VST forward declaration record.
2499     uint64_t VSTOffset = Stream.GetCurrentBitNo();
2500     // The BitcodeStartBit was the stream offset of the actual bitcode
2501     // (e.g. excluding any initial darwin header).
2502     VSTOffset -= bitcodeStartBit();
2503     assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
2504     Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32);
2505   }
2506 
2507   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
2508 
2509   // For the module-level VST, add abbrev Ids for the VST_CODE_FNENTRY
2510   // records, which are not used in the per-function VSTs.
2511   unsigned FnEntry8BitAbbrev;
2512   unsigned FnEntry7BitAbbrev;
2513   unsigned FnEntry6BitAbbrev;
2514   if (IsModuleLevel && hasVSTOffsetPlaceholder()) {
2515     // 8-bit fixed-width VST_CODE_FNENTRY function strings.
2516     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2517     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2518     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2519     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2520     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2521     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2522     FnEntry8BitAbbrev = Stream.EmitAbbrev(Abbv);
2523 
2524     // 7-bit fixed width VST_CODE_FNENTRY function strings.
2525     Abbv = new BitCodeAbbrev();
2526     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2527     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2528     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2529     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2530     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2531     FnEntry7BitAbbrev = Stream.EmitAbbrev(Abbv);
2532 
2533     // 6-bit char6 VST_CODE_FNENTRY function strings.
2534     Abbv = new BitCodeAbbrev();
2535     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2536     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2537     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2538     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2539     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2540     FnEntry6BitAbbrev = Stream.EmitAbbrev(Abbv);
2541   }
2542 
2543   // FIXME: Set up the abbrev, we know how many values there are!
2544   // FIXME: We know if the type names can use 7-bit ascii.
2545   SmallVector<unsigned, 64> NameVals;
2546 
2547   for (const ValueName &Name : VST) {
2548     // Figure out the encoding to use for the name.
2549     StringEncoding Bits =
2550         getStringEncoding(Name.getKeyData(), Name.getKeyLength());
2551 
2552     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
2553     NameVals.push_back(VE.getValueID(Name.getValue()));
2554 
2555     Function *F = dyn_cast<Function>(Name.getValue());
2556     if (!F) {
2557       // If value is an alias, need to get the aliased base object to
2558       // see if it is a function.
2559       auto *GA = dyn_cast<GlobalAlias>(Name.getValue());
2560       if (GA && GA->getBaseObject())
2561         F = dyn_cast<Function>(GA->getBaseObject());
2562     }
2563 
2564     // VST_CODE_ENTRY:   [valueid, namechar x N]
2565     // VST_CODE_FNENTRY: [valueid, funcoffset, namechar x N]
2566     // VST_CODE_BBENTRY: [bbid, namechar x N]
2567     unsigned Code;
2568     if (isa<BasicBlock>(Name.getValue())) {
2569       Code = bitc::VST_CODE_BBENTRY;
2570       if (Bits == SE_Char6)
2571         AbbrevToUse = VST_BBENTRY_6_ABBREV;
2572     } else if (F && !F->isDeclaration()) {
2573       // Must be the module-level VST, where we pass in the Index and
2574       // have a VSTOffsetPlaceholder. The function-level VST should not
2575       // contain any Function symbols.
2576       assert(FunctionToBitcodeIndex);
2577       assert(hasVSTOffsetPlaceholder());
2578 
2579       // Save the word offset of the function (from the start of the
2580       // actual bitcode written to the stream).
2581       uint64_t BitcodeIndex = (*FunctionToBitcodeIndex)[F] - bitcodeStartBit();
2582       assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
2583       NameVals.push_back(BitcodeIndex / 32);
2584 
2585       Code = bitc::VST_CODE_FNENTRY;
2586       AbbrevToUse = FnEntry8BitAbbrev;
2587       if (Bits == SE_Char6)
2588         AbbrevToUse = FnEntry6BitAbbrev;
2589       else if (Bits == SE_Fixed7)
2590         AbbrevToUse = FnEntry7BitAbbrev;
2591     } else {
2592       Code = bitc::VST_CODE_ENTRY;
2593       if (Bits == SE_Char6)
2594         AbbrevToUse = VST_ENTRY_6_ABBREV;
2595       else if (Bits == SE_Fixed7)
2596         AbbrevToUse = VST_ENTRY_7_ABBREV;
2597     }
2598 
2599     for (const auto P : Name.getKey())
2600       NameVals.push_back((unsigned char)P);
2601 
2602     // Emit the finished record.
2603     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
2604     NameVals.clear();
2605   }
2606   Stream.ExitBlock();
2607 }
2608 
2609 /// Emit function names and summary offsets for the combined index
2610 /// used by ThinLTO.
2611 void IndexBitcodeWriter::writeCombinedValueSymbolTable() {
2612   assert(hasVSTOffsetPlaceholder() && "Expected non-zero VSTOffsetPlaceholder");
2613   // Get the offset of the VST we are writing, and backpatch it into
2614   // the VST forward declaration record.
2615   uint64_t VSTOffset = Stream.GetCurrentBitNo();
2616   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
2617   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32);
2618 
2619   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
2620 
2621   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2622   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_COMBINED_GVDEFENTRY));
2623   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
2624   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // sumoffset
2625   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // guid
2626   unsigned DefEntryAbbrev = Stream.EmitAbbrev(Abbv);
2627 
2628   Abbv = new BitCodeAbbrev();
2629   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_COMBINED_ENTRY));
2630   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
2631   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // refguid
2632   unsigned EntryAbbrev = Stream.EmitAbbrev(Abbv);
2633 
2634   SmallVector<uint64_t, 64> NameVals;
2635 
2636   for (const auto &FII : Index) {
2637     GlobalValue::GUID FuncGUID = FII.first;
2638     unsigned ValueId = popValueId(FuncGUID);
2639 
2640     for (const auto &FI : FII.second) {
2641       // VST_CODE_COMBINED_GVDEFENTRY: [valueid, sumoffset, guid]
2642       NameVals.push_back(ValueId);
2643       NameVals.push_back(FI->bitcodeIndex());
2644       NameVals.push_back(FuncGUID);
2645 
2646       // Emit the finished record.
2647       Stream.EmitRecord(bitc::VST_CODE_COMBINED_GVDEFENTRY, NameVals,
2648                         DefEntryAbbrev);
2649       NameVals.clear();
2650     }
2651   }
2652   for (const auto &GVI : valueIds()) {
2653     // VST_CODE_COMBINED_ENTRY: [valueid, refguid]
2654     NameVals.push_back(GVI.second);
2655     NameVals.push_back(GVI.first);
2656 
2657     // Emit the finished record.
2658     Stream.EmitRecord(bitc::VST_CODE_COMBINED_ENTRY, NameVals, EntryAbbrev);
2659     NameVals.clear();
2660   }
2661   Stream.ExitBlock();
2662 }
2663 
2664 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
2665   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
2666   unsigned Code;
2667   if (isa<BasicBlock>(Order.V))
2668     Code = bitc::USELIST_CODE_BB;
2669   else
2670     Code = bitc::USELIST_CODE_DEFAULT;
2671 
2672   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
2673   Record.push_back(VE.getValueID(Order.V));
2674   Stream.EmitRecord(Code, Record);
2675 }
2676 
2677 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
2678   assert(VE.shouldPreserveUseListOrder() &&
2679          "Expected to be preserving use-list order");
2680 
2681   auto hasMore = [&]() {
2682     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
2683   };
2684   if (!hasMore())
2685     // Nothing to do.
2686     return;
2687 
2688   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
2689   while (hasMore()) {
2690     writeUseList(std::move(VE.UseListOrders.back()));
2691     VE.UseListOrders.pop_back();
2692   }
2693   Stream.ExitBlock();
2694 }
2695 
2696 /// Emit a function body to the module stream.
2697 void ModuleBitcodeWriter::writeFunction(
2698     const Function &F,
2699     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
2700   // Save the bitcode index of the start of this function block for recording
2701   // in the VST.
2702   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
2703 
2704   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
2705   VE.incorporateFunction(F);
2706 
2707   SmallVector<unsigned, 64> Vals;
2708 
2709   // Emit the number of basic blocks, so the reader can create them ahead of
2710   // time.
2711   Vals.push_back(VE.getBasicBlocks().size());
2712   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
2713   Vals.clear();
2714 
2715   // If there are function-local constants, emit them now.
2716   unsigned CstStart, CstEnd;
2717   VE.getFunctionConstantRange(CstStart, CstEnd);
2718   writeConstants(CstStart, CstEnd, false);
2719 
2720   // If there is function-local metadata, emit it now.
2721   writeFunctionMetadata(F);
2722 
2723   // Keep a running idea of what the instruction ID is.
2724   unsigned InstID = CstEnd;
2725 
2726   bool NeedsMetadataAttachment = F.hasMetadata();
2727 
2728   DILocation *LastDL = nullptr;
2729   // Finally, emit all the instructions, in order.
2730   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
2731     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
2732          I != E; ++I) {
2733       writeInstruction(*I, InstID, Vals);
2734 
2735       if (!I->getType()->isVoidTy())
2736         ++InstID;
2737 
2738       // If the instruction has metadata, write a metadata attachment later.
2739       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
2740 
2741       // If the instruction has a debug location, emit it.
2742       DILocation *DL = I->getDebugLoc();
2743       if (!DL)
2744         continue;
2745 
2746       if (DL == LastDL) {
2747         // Just repeat the same debug loc as last time.
2748         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
2749         continue;
2750       }
2751 
2752       Vals.push_back(DL->getLine());
2753       Vals.push_back(DL->getColumn());
2754       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
2755       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
2756       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
2757       Vals.clear();
2758 
2759       LastDL = DL;
2760     }
2761 
2762   // Emit names for all the instructions etc.
2763   writeValueSymbolTable(F.getValueSymbolTable());
2764 
2765   if (NeedsMetadataAttachment)
2766     writeMetadataAttachment(F);
2767   if (VE.shouldPreserveUseListOrder())
2768     writeUseListBlock(&F);
2769   VE.purgeFunction();
2770   Stream.ExitBlock();
2771 }
2772 
2773 // Emit blockinfo, which defines the standard abbreviations etc.
2774 void ModuleBitcodeWriter::writeBlockInfo() {
2775   // We only want to emit block info records for blocks that have multiple
2776   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
2777   // Other blocks can define their abbrevs inline.
2778   Stream.EnterBlockInfoBlock(2);
2779 
2780   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
2781     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2782     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
2783     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2784     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2785     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2786     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
2787         VST_ENTRY_8_ABBREV)
2788       llvm_unreachable("Unexpected abbrev ordering!");
2789   }
2790 
2791   { // 7-bit fixed width 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::Fixed, 7));
2797     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
2798         VST_ENTRY_7_ABBREV)
2799       llvm_unreachable("Unexpected abbrev ordering!");
2800   }
2801   { // 6-bit char6 VST_CODE_ENTRY strings.
2802     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2803     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
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_ENTRY_6_ABBREV)
2809       llvm_unreachable("Unexpected abbrev ordering!");
2810   }
2811   { // 6-bit char6 VST_CODE_BBENTRY strings.
2812     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2813     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
2814     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2815     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2816     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2817     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
2818         VST_BBENTRY_6_ABBREV)
2819       llvm_unreachable("Unexpected abbrev ordering!");
2820   }
2821 
2822 
2823 
2824   { // SETTYPE abbrev for CONSTANTS_BLOCK.
2825     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2826     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
2827     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
2828                               VE.computeBitsRequiredForTypeIndicies()));
2829     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
2830         CONSTANTS_SETTYPE_ABBREV)
2831       llvm_unreachable("Unexpected abbrev ordering!");
2832   }
2833 
2834   { // INTEGER abbrev for CONSTANTS_BLOCK.
2835     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2836     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
2837     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2838     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
2839         CONSTANTS_INTEGER_ABBREV)
2840       llvm_unreachable("Unexpected abbrev ordering!");
2841   }
2842 
2843   { // CE_CAST abbrev for CONSTANTS_BLOCK.
2844     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2845     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
2846     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
2847     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
2848                               VE.computeBitsRequiredForTypeIndicies()));
2849     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
2850 
2851     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
2852         CONSTANTS_CE_CAST_Abbrev)
2853       llvm_unreachable("Unexpected abbrev ordering!");
2854   }
2855   { // NULL abbrev for CONSTANTS_BLOCK.
2856     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2857     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
2858     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
2859         CONSTANTS_NULL_Abbrev)
2860       llvm_unreachable("Unexpected abbrev ordering!");
2861   }
2862 
2863   // FIXME: This should only use space for first class types!
2864 
2865   { // INST_LOAD abbrev for FUNCTION_BLOCK.
2866     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2867     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
2868     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
2869     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
2870                               VE.computeBitsRequiredForTypeIndicies()));
2871     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
2872     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
2873     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2874         FUNCTION_INST_LOAD_ABBREV)
2875       llvm_unreachable("Unexpected abbrev ordering!");
2876   }
2877   { // INST_BINOP 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     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2884         FUNCTION_INST_BINOP_ABBREV)
2885       llvm_unreachable("Unexpected abbrev ordering!");
2886   }
2887   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
2888     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2889     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2890     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2891     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2892     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2893     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
2894     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2895         FUNCTION_INST_BINOP_FLAGS_ABBREV)
2896       llvm_unreachable("Unexpected abbrev ordering!");
2897   }
2898   { // INST_CAST abbrev for FUNCTION_BLOCK.
2899     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2900     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
2901     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
2902     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
2903                               VE.computeBitsRequiredForTypeIndicies()));
2904     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
2905     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2906         FUNCTION_INST_CAST_ABBREV)
2907       llvm_unreachable("Unexpected abbrev ordering!");
2908   }
2909 
2910   { // INST_RET abbrev for FUNCTION_BLOCK.
2911     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2912     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2913     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2914         FUNCTION_INST_RET_VOID_ABBREV)
2915       llvm_unreachable("Unexpected abbrev ordering!");
2916   }
2917   { // INST_RET abbrev for FUNCTION_BLOCK.
2918     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2919     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2920     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
2921     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2922         FUNCTION_INST_RET_VAL_ABBREV)
2923       llvm_unreachable("Unexpected abbrev ordering!");
2924   }
2925   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
2926     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2927     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
2928     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2929         FUNCTION_INST_UNREACHABLE_ABBREV)
2930       llvm_unreachable("Unexpected abbrev ordering!");
2931   }
2932   {
2933     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2934     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
2935     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2936     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
2937                               Log2_32_Ceil(VE.getTypes().size() + 1)));
2938     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2939     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2940     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2941         FUNCTION_INST_GEP_ABBREV)
2942       llvm_unreachable("Unexpected abbrev ordering!");
2943   }
2944 
2945   Stream.ExitBlock();
2946 }
2947 
2948 /// Write the module path strings, currently only used when generating
2949 /// a combined index file.
2950 void IndexBitcodeWriter::writeModStrings() {
2951   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
2952 
2953   // TODO: See which abbrev sizes we actually need to emit
2954 
2955   // 8-bit fixed-width MST_ENTRY strings.
2956   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2957   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
2958   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2959   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2960   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2961   unsigned Abbrev8Bit = Stream.EmitAbbrev(Abbv);
2962 
2963   // 7-bit fixed width MST_ENTRY strings.
2964   Abbv = new BitCodeAbbrev();
2965   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
2966   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2967   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2968   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2969   unsigned Abbrev7Bit = Stream.EmitAbbrev(Abbv);
2970 
2971   // 6-bit char6 MST_ENTRY strings.
2972   Abbv = new BitCodeAbbrev();
2973   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
2974   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2975   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2976   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2977   unsigned Abbrev6Bit = Stream.EmitAbbrev(Abbv);
2978 
2979   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
2980   Abbv = new BitCodeAbbrev();
2981   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
2982   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2983   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2984   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2985   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2986   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2987   unsigned AbbrevHash = Stream.EmitAbbrev(Abbv);
2988 
2989   SmallVector<unsigned, 64> Vals;
2990   for (const auto &MPSE : Index.modulePaths()) {
2991     StringEncoding Bits =
2992         getStringEncoding(MPSE.getKey().data(), MPSE.getKey().size());
2993     unsigned AbbrevToUse = Abbrev8Bit;
2994     if (Bits == SE_Char6)
2995       AbbrevToUse = Abbrev6Bit;
2996     else if (Bits == SE_Fixed7)
2997       AbbrevToUse = Abbrev7Bit;
2998 
2999     Vals.push_back(MPSE.getValue().first);
3000 
3001     for (const auto P : MPSE.getKey())
3002       Vals.push_back((unsigned char)P);
3003 
3004     // Emit the finished record.
3005     Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3006 
3007     Vals.clear();
3008     // Emit an optional hash for the module now
3009     auto &Hash = MPSE.getValue().second;
3010     bool AllZero = true; // Detect if the hash is empty, and do not generate it
3011     for (auto Val : Hash) {
3012       if (Val)
3013         AllZero = false;
3014       Vals.push_back(Val);
3015     }
3016     if (!AllZero) {
3017       // Emit the hash record.
3018       Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3019     }
3020 
3021     Vals.clear();
3022   }
3023   Stream.ExitBlock();
3024 }
3025 
3026 // Helper to emit a single function summary record.
3027 void ModuleBitcodeWriter::writePerModuleFunctionSummaryRecord(
3028     SmallVector<uint64_t, 64> &NameVals, GlobalValueInfo *Info,
3029     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3030     const Function &F) {
3031   NameVals.push_back(ValueID);
3032 
3033   FunctionSummary *FS = cast<FunctionSummary>(Info->summary());
3034   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3035   NameVals.push_back(FS->instCount());
3036   NameVals.push_back(FS->refs().size());
3037 
3038   for (auto &RI : FS->refs())
3039     NameVals.push_back(VE.getValueID(RI.getValue()));
3040 
3041   bool HasProfileData = F.getEntryCount().hasValue();
3042   for (auto &ECI : FS->calls()) {
3043     NameVals.push_back(VE.getValueID(ECI.first.getValue()));
3044     assert(ECI.second.CallsiteCount > 0 && "Expected at least one callsite");
3045     NameVals.push_back(ECI.second.CallsiteCount);
3046     if (HasProfileData)
3047       NameVals.push_back(ECI.second.ProfileCount);
3048   }
3049 
3050   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3051   unsigned Code =
3052       (HasProfileData ? bitc::FS_PERMODULE_PROFILE : bitc::FS_PERMODULE);
3053 
3054   // Emit the finished record.
3055   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3056   NameVals.clear();
3057 }
3058 
3059 // Collect the global value references in the given variable's initializer,
3060 // and emit them in a summary record.
3061 void ModuleBitcodeWriter::writeModuleLevelReferences(
3062     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3063     unsigned FSModRefsAbbrev) {
3064   // Only interested in recording variable defs in the summary.
3065   if (V.isDeclaration())
3066     return;
3067   NameVals.push_back(VE.getValueID(&V));
3068   NameVals.push_back(getEncodedGVSummaryFlags(V));
3069   auto *Info = Index->getGlobalValueInfo(V);
3070   GlobalVarSummary *VS = cast<GlobalVarSummary>(Info->summary());
3071   for (auto Ref : VS->refs())
3072     NameVals.push_back(VE.getValueID(Ref.getValue()));
3073   Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3074                     FSModRefsAbbrev);
3075   NameVals.clear();
3076 }
3077 
3078 // Current version for the summary.
3079 // This is bumped whenever we introduce changes in the way some record are
3080 // interpreted, like flags for instance.
3081 static const uint64_t INDEX_VERSION = 1;
3082 
3083 /// Emit the per-module summary section alongside the rest of
3084 /// the module's bitcode.
3085 void ModuleBitcodeWriter::writePerModuleGlobalValueSummary() {
3086   if (M.empty())
3087     return;
3088 
3089   if (Index->begin() == Index->end())
3090     return;
3091 
3092   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 4);
3093 
3094   Stream.EmitRecord(bitc::FS_VERSION, ArrayRef<uint64_t>{INDEX_VERSION});
3095 
3096   // Abbrev for FS_PERMODULE.
3097   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3098   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
3099   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3100   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3101   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3102   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3103   // numrefs x valueid, n x (valueid, callsitecount)
3104   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3105   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3106   unsigned FSCallsAbbrev = Stream.EmitAbbrev(Abbv);
3107 
3108   // Abbrev for FS_PERMODULE_PROFILE.
3109   Abbv = new BitCodeAbbrev();
3110   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
3111   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3112   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3113   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3114   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3115   // numrefs x valueid, n x (valueid, callsitecount, profilecount)
3116   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3117   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3118   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(Abbv);
3119 
3120   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
3121   Abbv = new BitCodeAbbrev();
3122   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
3123   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3124   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3125   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
3126   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3127   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(Abbv);
3128 
3129   // Abbrev for FS_ALIAS.
3130   Abbv = new BitCodeAbbrev();
3131   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
3132   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3133   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3134   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3135   unsigned FSAliasAbbrev = Stream.EmitAbbrev(Abbv);
3136 
3137   SmallVector<uint64_t, 64> NameVals;
3138   // Iterate over the list of functions instead of the Index to
3139   // ensure the ordering is stable.
3140   for (const Function &F : M) {
3141     if (F.isDeclaration())
3142       continue;
3143     // Summary emission does not support anonymous functions, they have to
3144     // renamed using the anonymous function renaming pass.
3145     if (!F.hasName())
3146       report_fatal_error("Unexpected anonymous function when writing summary");
3147 
3148     auto *Info = Index->getGlobalValueInfo(F);
3149     writePerModuleFunctionSummaryRecord(
3150         NameVals, Info,
3151         VE.getValueID(M.getValueSymbolTable().lookup(F.getName())),
3152         FSCallsAbbrev, FSCallsProfileAbbrev, F);
3153   }
3154 
3155   // Capture references from GlobalVariable initializers, which are outside
3156   // of a function scope.
3157   for (const GlobalVariable &G : M.globals())
3158     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev);
3159 
3160   for (const GlobalAlias &A : M.aliases()) {
3161     auto *Aliasee = A.getBaseObject();
3162     if (!Aliasee->hasName())
3163       // Nameless function don't have an entry in the summary, skip it.
3164       continue;
3165     auto AliasId = VE.getValueID(&A);
3166     auto AliaseeId = VE.getValueID(Aliasee);
3167     NameVals.push_back(AliasId);
3168     NameVals.push_back(getEncodedGVSummaryFlags(A));
3169     NameVals.push_back(AliaseeId);
3170     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
3171     NameVals.clear();
3172   }
3173 
3174   Stream.ExitBlock();
3175 }
3176 
3177 /// Emit the combined summary section into the combined index file.
3178 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
3179   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
3180   Stream.EmitRecord(bitc::FS_VERSION, ArrayRef<uint64_t>{INDEX_VERSION});
3181 
3182   // Abbrev for FS_COMBINED.
3183   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3184   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
3185   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3186   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3187   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3188   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3189   // numrefs x valueid, n x (valueid, callsitecount)
3190   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3191   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3192   unsigned FSCallsAbbrev = Stream.EmitAbbrev(Abbv);
3193 
3194   // Abbrev for FS_COMBINED_PROFILE.
3195   Abbv = new BitCodeAbbrev();
3196   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
3197   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3198   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3199   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3200   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3201   // numrefs x valueid, n x (valueid, callsitecount, profilecount)
3202   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3203   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3204   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(Abbv);
3205 
3206   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
3207   Abbv = new BitCodeAbbrev();
3208   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
3209   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3210   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3211   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
3212   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3213   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(Abbv);
3214 
3215   // Abbrev for FS_COMBINED_ALIAS.
3216   Abbv = new BitCodeAbbrev();
3217   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
3218   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3219   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3220   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // offset
3221   unsigned FSAliasAbbrev = Stream.EmitAbbrev(Abbv);
3222 
3223   // The aliases are emitted as a post-pass, and will point to the summary
3224   // offset id of the aliasee. For this purpose we need to be able to get back
3225   // from the summary to the offset
3226   SmallVector<GlobalValueInfo *, 64> Aliases;
3227   DenseMap<const GlobalValueSummary *, uint64_t> SummaryToOffsetMap;
3228 
3229   SmallVector<uint64_t, 64> NameVals;
3230 
3231   // For local linkage, we also emit the original name separately
3232   // immediately after the record.
3233   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
3234     if (!GlobalValue::isLocalLinkage(S.linkage()))
3235       return;
3236     NameVals.push_back(S.getOriginalName());
3237     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
3238     NameVals.clear();
3239   };
3240 
3241   for (const auto &FII : Index) {
3242     for (auto &FI : FII.second) {
3243       GlobalValueSummary *S = FI->summary();
3244       assert(S);
3245       if (isa<AliasSummary>(S)) {
3246         // Will process aliases as a post-pass because the reader wants all
3247         // global to be loaded first.
3248         Aliases.push_back(FI.get());
3249         continue;
3250       }
3251 
3252       if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
3253         NameVals.push_back(Index.getModuleId(VS->modulePath()));
3254         NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3255         for (auto &RI : VS->refs()) {
3256           NameVals.push_back(getValueId(RI.getGUID()));
3257         }
3258 
3259         // Record the starting offset of this summary entry for use
3260         // in the VST entry. Add the current code size since the
3261         // reader will invoke readRecord after the abbrev id read.
3262         FI->setBitcodeIndex(Stream.GetCurrentBitNo() +
3263                             Stream.GetAbbrevIDWidth());
3264         // Store temporarily the offset in the map for a possible alias.
3265         SummaryToOffsetMap[S] = FI->bitcodeIndex();
3266 
3267         // Emit the finished record.
3268         Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
3269                           FSModRefsAbbrev);
3270         NameVals.clear();
3271         MaybeEmitOriginalName(*S);
3272         continue;
3273       }
3274 
3275       auto *FS = cast<FunctionSummary>(S);
3276       NameVals.push_back(Index.getModuleId(FS->modulePath()));
3277       NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3278       NameVals.push_back(FS->instCount());
3279       NameVals.push_back(FS->refs().size());
3280 
3281       for (auto &RI : FS->refs()) {
3282         NameVals.push_back(getValueId(RI.getGUID()));
3283       }
3284 
3285       bool HasProfileData = false;
3286       for (auto &EI : FS->calls()) {
3287         HasProfileData |= EI.second.ProfileCount != 0;
3288         if (HasProfileData)
3289           break;
3290       }
3291 
3292       for (auto &EI : FS->calls()) {
3293         // If this GUID doesn't have a value id, it doesn't have a function
3294         // summary and we don't need to record any calls to it.
3295         if (!hasValueId(EI.first.getGUID()))
3296           continue;
3297         NameVals.push_back(getValueId(EI.first.getGUID()));
3298         assert(EI.second.CallsiteCount > 0 && "Expected at least one callsite");
3299         NameVals.push_back(EI.second.CallsiteCount);
3300         if (HasProfileData)
3301           NameVals.push_back(EI.second.ProfileCount);
3302       }
3303 
3304       // Record the starting offset of this summary entry for use
3305       // in the VST entry. Add the current code size since the
3306       // reader will invoke readRecord after the abbrev id read.
3307       FI->setBitcodeIndex(Stream.GetCurrentBitNo() + Stream.GetAbbrevIDWidth());
3308       // Store temporarily the offset in the map for a possible alias.
3309       SummaryToOffsetMap[S] = FI->bitcodeIndex();
3310 
3311       unsigned FSAbbrev =
3312           (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3313       unsigned Code =
3314           (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
3315 
3316       // Emit the finished record.
3317       Stream.EmitRecord(Code, NameVals, FSAbbrev);
3318       NameVals.clear();
3319       MaybeEmitOriginalName(*S);
3320     }
3321   }
3322 
3323   for (auto GVI : Aliases) {
3324     AliasSummary *AS = cast<AliasSummary>(GVI->summary());
3325     NameVals.push_back(Index.getModuleId(AS->modulePath()));
3326     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
3327     auto AliaseeOffset = SummaryToOffsetMap[&AS->getAliasee()];
3328     assert(AliaseeOffset);
3329     NameVals.push_back(AliaseeOffset);
3330 
3331     // Record the starting offset of this summary entry for use
3332     // in the VST entry. Add the current code size since the
3333     // reader will invoke readRecord after the abbrev id read.
3334     GVI->setBitcodeIndex(Stream.GetCurrentBitNo() + Stream.GetAbbrevIDWidth());
3335 
3336     // Emit the finished record.
3337     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
3338     NameVals.clear();
3339     MaybeEmitOriginalName(*AS);
3340   }
3341 
3342   Stream.ExitBlock();
3343 }
3344 
3345 void ModuleBitcodeWriter::writeIdentificationBlock() {
3346   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
3347 
3348   // Write the "user readable" string identifying the bitcode producer
3349   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3350   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
3351   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3352   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3353   auto StringAbbrev = Stream.EmitAbbrev(Abbv);
3354   writeStringRecord(bitc::IDENTIFICATION_CODE_STRING,
3355                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
3356 
3357   // Write the epoch version
3358   Abbv = new BitCodeAbbrev();
3359   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
3360   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3361   auto EpochAbbrev = Stream.EmitAbbrev(Abbv);
3362   SmallVector<unsigned, 1> Vals = {bitc::BITCODE_CURRENT_EPOCH};
3363   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
3364   Stream.ExitBlock();
3365 }
3366 
3367 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
3368   // Emit the module's hash.
3369   // MODULE_CODE_HASH: [5*i32]
3370   SHA1 Hasher;
3371   Hasher.update(ArrayRef<uint8_t>((uint8_t *)&(Buffer)[BlockStartPos],
3372                                   Buffer.size() - BlockStartPos));
3373   auto Hash = Hasher.result();
3374   SmallVector<uint64_t, 20> Vals;
3375   auto LShift = [&](unsigned char Val, unsigned Amount)
3376                     -> uint64_t { return ((uint64_t)Val) << Amount; };
3377   for (int Pos = 0; Pos < 20; Pos += 4) {
3378     uint32_t SubHash = LShift(Hash[Pos + 0], 24);
3379     SubHash |= LShift(Hash[Pos + 1], 16) | LShift(Hash[Pos + 2], 8) |
3380                (unsigned)(unsigned char)Hash[Pos + 3];
3381     Vals.push_back(SubHash);
3382   }
3383 
3384   // Emit the finished record.
3385   Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
3386 }
3387 
3388 void BitcodeWriter::write() {
3389   // Emit the file header first.
3390   writeBitcodeHeader();
3391 
3392   writeBlocks();
3393 }
3394 
3395 void ModuleBitcodeWriter::writeBlocks() {
3396   writeIdentificationBlock();
3397   writeModule();
3398 }
3399 
3400 void IndexBitcodeWriter::writeBlocks() {
3401   // Index contains only a single outer (module) block.
3402   writeIndex();
3403 }
3404 
3405 void ModuleBitcodeWriter::writeModule() {
3406   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
3407   size_t BlockStartPos = Buffer.size();
3408 
3409   SmallVector<unsigned, 1> Vals;
3410   unsigned CurVersion = 1;
3411   Vals.push_back(CurVersion);
3412   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
3413 
3414   // Emit blockinfo, which defines the standard abbreviations etc.
3415   writeBlockInfo();
3416 
3417   // Emit information about attribute groups.
3418   writeAttributeGroupTable();
3419 
3420   // Emit information about parameter attributes.
3421   writeAttributeTable();
3422 
3423   // Emit information describing all of the types in the module.
3424   writeTypeTable();
3425 
3426   writeComdats();
3427 
3428   // Emit top-level description of module, including target triple, inline asm,
3429   // descriptors for global variables, and function prototype info.
3430   writeModuleInfo();
3431 
3432   // Emit constants.
3433   writeModuleConstants();
3434 
3435   // Emit metadata.
3436   writeModuleMetadata();
3437 
3438   // Emit metadata.
3439   writeModuleMetadataStore();
3440 
3441   // Emit module-level use-lists.
3442   if (VE.shouldPreserveUseListOrder())
3443     writeUseListBlock(nullptr);
3444 
3445   writeOperandBundleTags();
3446 
3447   // Emit function bodies.
3448   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
3449   for (Module::const_iterator F = M.begin(), E = M.end(); F != E; ++F)
3450     if (!F->isDeclaration())
3451       writeFunction(*F, FunctionToBitcodeIndex);
3452 
3453   // Need to write after the above call to WriteFunction which populates
3454   // the summary information in the index.
3455   if (Index)
3456     writePerModuleGlobalValueSummary();
3457 
3458   writeValueSymbolTable(M.getValueSymbolTable(),
3459                         /* IsModuleLevel */ true, &FunctionToBitcodeIndex);
3460 
3461   if (GenerateHash) {
3462     writeModuleHash(BlockStartPos);
3463   }
3464 
3465   Stream.ExitBlock();
3466 }
3467 
3468 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
3469                                uint32_t &Position) {
3470   support::endian::write32le(&Buffer[Position], Value);
3471   Position += 4;
3472 }
3473 
3474 /// If generating a bc file on darwin, we have to emit a
3475 /// header and trailer to make it compatible with the system archiver.  To do
3476 /// this we emit the following header, and then emit a trailer that pads the
3477 /// file out to be a multiple of 16 bytes.
3478 ///
3479 /// struct bc_header {
3480 ///   uint32_t Magic;         // 0x0B17C0DE
3481 ///   uint32_t Version;       // Version, currently always 0.
3482 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
3483 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
3484 ///   uint32_t CPUType;       // CPU specifier.
3485 ///   ... potentially more later ...
3486 /// };
3487 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
3488                                          const Triple &TT) {
3489   unsigned CPUType = ~0U;
3490 
3491   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
3492   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
3493   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
3494   // specific constants here because they are implicitly part of the Darwin ABI.
3495   enum {
3496     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
3497     DARWIN_CPU_TYPE_X86        = 7,
3498     DARWIN_CPU_TYPE_ARM        = 12,
3499     DARWIN_CPU_TYPE_POWERPC    = 18
3500   };
3501 
3502   Triple::ArchType Arch = TT.getArch();
3503   if (Arch == Triple::x86_64)
3504     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
3505   else if (Arch == Triple::x86)
3506     CPUType = DARWIN_CPU_TYPE_X86;
3507   else if (Arch == Triple::ppc)
3508     CPUType = DARWIN_CPU_TYPE_POWERPC;
3509   else if (Arch == Triple::ppc64)
3510     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
3511   else if (Arch == Triple::arm || Arch == Triple::thumb)
3512     CPUType = DARWIN_CPU_TYPE_ARM;
3513 
3514   // Traditional Bitcode starts after header.
3515   assert(Buffer.size() >= BWH_HeaderSize &&
3516          "Expected header size to be reserved");
3517   unsigned BCOffset = BWH_HeaderSize;
3518   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
3519 
3520   // Write the magic and version.
3521   unsigned Position = 0;
3522   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
3523   writeInt32ToBuffer(0, Buffer, Position); // Version.
3524   writeInt32ToBuffer(BCOffset, Buffer, Position);
3525   writeInt32ToBuffer(BCSize, Buffer, Position);
3526   writeInt32ToBuffer(CPUType, Buffer, Position);
3527 
3528   // If the file is not a multiple of 16 bytes, insert dummy padding.
3529   while (Buffer.size() & 15)
3530     Buffer.push_back(0);
3531 }
3532 
3533 /// Helper to write the header common to all bitcode files.
3534 void BitcodeWriter::writeBitcodeHeader() {
3535   // Emit the file header.
3536   Stream.Emit((unsigned)'B', 8);
3537   Stream.Emit((unsigned)'C', 8);
3538   Stream.Emit(0x0, 4);
3539   Stream.Emit(0xC, 4);
3540   Stream.Emit(0xE, 4);
3541   Stream.Emit(0xD, 4);
3542 }
3543 
3544 /// WriteBitcodeToFile - Write the specified module to the specified output
3545 /// stream.
3546 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out,
3547                               bool ShouldPreserveUseListOrder,
3548                               const ModuleSummaryIndex *Index,
3549                               bool GenerateHash) {
3550   SmallVector<char, 0> Buffer;
3551   Buffer.reserve(256*1024);
3552 
3553   // If this is darwin or another generic macho target, reserve space for the
3554   // header.
3555   Triple TT(M->getTargetTriple());
3556   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
3557     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
3558 
3559   // Emit the module into the buffer.
3560   ModuleBitcodeWriter ModuleWriter(M, Buffer, ShouldPreserveUseListOrder, Index,
3561                                    GenerateHash);
3562   ModuleWriter.write();
3563 
3564   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
3565     emitDarwinBCHeaderAndTrailer(Buffer, TT);
3566 
3567   // Write the generated bitstream to "Out".
3568   Out.write((char*)&Buffer.front(), Buffer.size());
3569 }
3570 
3571 void IndexBitcodeWriter::writeIndex() {
3572   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
3573 
3574   SmallVector<unsigned, 1> Vals;
3575   unsigned CurVersion = 1;
3576   Vals.push_back(CurVersion);
3577   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
3578 
3579   // If we have a VST, write the VSTOFFSET record placeholder.
3580   writeValueSymbolTableForwardDecl();
3581 
3582   // Write the module paths in the combined index.
3583   writeModStrings();
3584 
3585   // Write the summary combined index records.
3586   writeCombinedGlobalValueSummary();
3587 
3588   // Need a special VST writer for the combined index (we don't have a
3589   // real VST and real values when this is invoked).
3590   writeCombinedValueSymbolTable();
3591 
3592   Stream.ExitBlock();
3593 }
3594 
3595 // Write the specified module summary index to the given raw output stream,
3596 // where it will be written in a new bitcode block. This is used when
3597 // writing the combined index file for ThinLTO.
3598 void llvm::WriteIndexToFile(const ModuleSummaryIndex &Index, raw_ostream &Out) {
3599   SmallVector<char, 0> Buffer;
3600   Buffer.reserve(256 * 1024);
3601 
3602   IndexBitcodeWriter IndexWriter(Buffer, Index);
3603   IndexWriter.write();
3604 
3605   Out.write((char *)&Buffer.front(), Buffer.size());
3606 }
3607