xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision 37687f3911e7e7be93ee3085946313fe240d3187)
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 /// Class to manage the bitcode writing for all bitcode file types.
67 /// Owns the BitstreamWriter, and includes the main entry point for
68 /// writing.
69 class BitcodeWriter {
70   /// Pointer to the buffer allocated by caller for bitcode writing.
71   SmallVectorImpl<char> *Buffer;
72 
73   /// The stream created and owned by the BitodeWriter.
74   BitstreamWriter Stream;
75 
76   /// Saves the offset of the VSTOffset record that must eventually be
77   /// backpatched with the offset of the actual VST.
78   uint64_t VSTOffsetPlaceholder = 0;
79 
80 public:
81   /// Constructs a BitcodeWriter object, and initializes a BitstreamRecord,
82   /// writing to the provided \p Buffer.
83   BitcodeWriter(SmallVectorImpl<char> *Buffer)
84       : Buffer(Buffer), Stream(*Buffer) {}
85 
86   virtual ~BitcodeWriter() = default;
87 
88   /// Main entry point to write the bitcode file, which writes the bitcode
89   /// header and will then invoke the virtual writeBlocks() method.
90   void write();
91 
92 private:
93   /// Derived classes must implement this to write the corresponding blocks for
94   /// that bitcode file type.
95   virtual void writeBlocks() = 0;
96 
97 protected:
98   bool hasVSTOffsetPlaceholder() { return VSTOffsetPlaceholder != 0; }
99   uint64_t getVSTOffsetPlaceholder() { return VSTOffsetPlaceholder; }
100   SmallVectorImpl<char> &buffer() { return *Buffer; }
101   BitstreamWriter &stream() { return Stream; }
102   void writeValueSymbolTableForwardDecl();
103   void writeBitcodeHeader();
104 };
105 
106 /// Class to manage the bitcode writing for a module.
107 class ModuleBitcodeWriter : public BitcodeWriter {
108   /// The Module to write to bitcode.
109   const Module *M;
110 
111   /// Enumerates ids for all values in the module.
112   ValueEnumerator VE;
113 
114   /// Optional per-module index to write for ThinLTO.
115   const ModuleSummaryIndex *Index;
116 
117   /// True if a module hash record should be written.
118   bool GenerateHash;
119 
120   /// The start bit of the module block, for use in generating a module hash
121   uint64_t BitcodeStartBit = 0;
122 
123 public:
124   /// Constructs a ModuleBitcodeWriter object for the given Module,
125   /// writing to the provided \p Buffer.
126   ModuleBitcodeWriter(const Module *M, SmallVectorImpl<char> *Buffer,
127                       bool ShouldPreserveUseListOrder,
128                       const ModuleSummaryIndex *Index, bool GenerateHash)
129       : BitcodeWriter(Buffer), M(M), VE(*M, ShouldPreserveUseListOrder),
130         Index(Index), GenerateHash(GenerateHash) {
131     // Save the start bit of the actual bitcode, in case there is space
132     // saved at the start for the darwin header above. The reader stream
133     // will start at the bitcode, and we need the offset of the VST
134     // to line up.
135     BitcodeStartBit = stream().GetCurrentBitNo();
136   }
137 
138 private:
139   /// Main entry point for writing a module to bitcode, invoked by
140   /// BitcodeWriter::write() after it writes the header.
141   void writeBlocks() override;
142 
143   /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
144   /// current llvm version, and a record for the epoch number.
145   void writeIdentificationBlock();
146 
147   /// Emit the current module to the bitstream.
148   void writeModule();
149 
150   uint64_t bitcodeStartBit() { return BitcodeStartBit; }
151 
152   void writeStringRecord(unsigned Code, StringRef Str, unsigned AbbrevToUse);
153   void writeAttributeGroupTable();
154   void writeAttributeTable();
155   void writeTypeTable();
156   void writeComdats();
157   void writeModuleInfo();
158   void writeValueAsMetadata(const ValueAsMetadata *MD,
159                             SmallVectorImpl<uint64_t> &Record);
160   void writeMDTuple(const MDTuple *N, SmallVectorImpl<uint64_t> &Record,
161                     unsigned Abbrev);
162   unsigned createDILocationAbbrev();
163   void writeDILocation(const DILocation *N, SmallVectorImpl<uint64_t> &Record,
164                        unsigned &Abbrev);
165   unsigned createGenericDINodeAbbrev();
166   void writeGenericDINode(const GenericDINode *N,
167                           SmallVectorImpl<uint64_t> &Record, unsigned &Abbrev);
168   void writeDISubrange(const DISubrange *N, SmallVectorImpl<uint64_t> &Record,
169                        unsigned Abbrev);
170   void writeDIEnumerator(const DIEnumerator *N,
171                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
172   void writeDIBasicType(const DIBasicType *N, SmallVectorImpl<uint64_t> &Record,
173                         unsigned Abbrev);
174   void writeDIDerivedType(const DIDerivedType *N,
175                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
176   void writeDICompositeType(const DICompositeType *N,
177                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
178   void writeDISubroutineType(const DISubroutineType *N,
179                              SmallVectorImpl<uint64_t> &Record,
180                              unsigned Abbrev);
181   void writeDIFile(const DIFile *N, SmallVectorImpl<uint64_t> &Record,
182                    unsigned Abbrev);
183   void writeDICompileUnit(const DICompileUnit *N,
184                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
185   void writeDISubprogram(const DISubprogram *N,
186                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
187   void writeDILexicalBlock(const DILexicalBlock *N,
188                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
189   void writeDILexicalBlockFile(const DILexicalBlockFile *N,
190                                SmallVectorImpl<uint64_t> &Record,
191                                unsigned Abbrev);
192   void writeDINamespace(const DINamespace *N, SmallVectorImpl<uint64_t> &Record,
193                         unsigned Abbrev);
194   void writeDIMacro(const DIMacro *N, SmallVectorImpl<uint64_t> &Record,
195                     unsigned Abbrev);
196   void writeDIMacroFile(const DIMacroFile *N, SmallVectorImpl<uint64_t> &Record,
197                         unsigned Abbrev);
198   void writeDIModule(const DIModule *N, SmallVectorImpl<uint64_t> &Record,
199                      unsigned Abbrev);
200   void writeDITemplateTypeParameter(const DITemplateTypeParameter *N,
201                                     SmallVectorImpl<uint64_t> &Record,
202                                     unsigned Abbrev);
203   void writeDITemplateValueParameter(const DITemplateValueParameter *N,
204                                      SmallVectorImpl<uint64_t> &Record,
205                                      unsigned Abbrev);
206   void writeDIGlobalVariable(const DIGlobalVariable *N,
207                              SmallVectorImpl<uint64_t> &Record,
208                              unsigned Abbrev);
209   void writeDILocalVariable(const DILocalVariable *N,
210                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
211   void writeDIExpression(const DIExpression *N,
212                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
213   void writeDIObjCProperty(const DIObjCProperty *N,
214                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
215   void writeDIImportedEntity(const DIImportedEntity *N,
216                              SmallVectorImpl<uint64_t> &Record,
217                              unsigned Abbrev);
218   unsigned createNamedMetadataAbbrev();
219   void writeNamedMetadata(SmallVectorImpl<uint64_t> &Record);
220   unsigned createMetadataStringsAbbrev();
221   void writeMetadataStrings(ArrayRef<const Metadata *> Strings,
222                             SmallVectorImpl<uint64_t> &Record);
223   void writeMetadataRecords(ArrayRef<const Metadata *> MDs,
224                             SmallVectorImpl<uint64_t> &Record);
225   void writeModuleMetadata();
226   void writeFunctionMetadata(const Function &F);
227   void writeMetadataAttachment(const Function &F);
228   void writeModuleMetadataStore();
229   void writeOperandBundleTags();
230   void writeConstants(unsigned FirstVal, unsigned LastVal, bool isGlobal);
231   void writeModuleConstants();
232   bool pushValueAndType(const Value *V, unsigned InstID,
233                         SmallVectorImpl<unsigned> &Vals);
234   void writeOperandBundles(ImmutableCallSite CS, unsigned InstID);
235   void pushValue(const Value *V, unsigned InstID,
236                  SmallVectorImpl<unsigned> &Vals);
237   void pushValueSigned(const Value *V, unsigned InstID,
238                        SmallVectorImpl<uint64_t> &Vals);
239   void writeInstruction(const Instruction &I, unsigned InstID,
240                         SmallVectorImpl<unsigned> &Vals);
241   void writeValueSymbolTable(
242       const ValueSymbolTable &VST, bool IsModuleLevel = false,
243       DenseMap<const Function *, uint64_t> *FunctionToBitcodeIndex = nullptr);
244   void writeUseList(UseListOrder &&Order);
245   void writeUseListBlock(const Function *F);
246   void
247   writeFunction(const Function &F,
248                 DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
249   void writeBlockInfo();
250   void writePerModuleFunctionSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
251                                            GlobalValueInfo *Info,
252                                            unsigned ValueID,
253                                            unsigned FSCallsAbbrev,
254                                            unsigned FSCallsProfileAbbrev,
255                                            const Function &F);
256   void writeModuleLevelReferences(const GlobalVariable &V,
257                                   SmallVector<uint64_t, 64> &NameVals,
258                                   unsigned FSModRefsAbbrev);
259   void writePerModuleGlobalValueSummary();
260   void writeModuleHash(size_t BlockStartPos);
261 };
262 
263 /// Class to manage the bitcode writing for a combined index.
264 class IndexBitcodeWriter : public BitcodeWriter {
265   /// The combined index to write to bitcode.
266   const ModuleSummaryIndex *Index;
267 
268   /// Map that holds the correspondence between the GUID used in the combined
269   /// index and a value id generated by this class to use in references.
270   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
271 
272   /// Tracks the last value id recorded in the GUIDToValueMap.
273   unsigned GlobalValueId = 0;
274 
275 public:
276   /// Constructs a IndexBitcodeWriter object for the given combined index,
277   /// writing to the provided \p Buffer.
278   IndexBitcodeWriter(SmallVectorImpl<char> *Buffer,
279                      const ModuleSummaryIndex *Index)
280       : BitcodeWriter(Buffer), Index(Index) {
281     // Assign unique value ids to all functions in the index for use
282     // in writing out the call graph edges. Save the mapping from GUID
283     // to the new global value id to use when writing those edges, which
284     // are currently saved in the index in terms of GUID.
285     for (auto &II : *Index)
286       GUIDToValueIdMap[II.first] = ++GlobalValueId;
287   }
288 
289 private:
290   /// Main entry point for writing a combined index to bitcode, invoked by
291   /// BitcodeWriter::write() after it writes the header.
292   void writeBlocks() override;
293 
294   void writeIndex();
295   void writeModStrings();
296   void writeCombinedValueSymbolTable();
297   void writeCombinedGlobalValueSummary();
298 
299   bool hasValueId(GlobalValue::GUID ValGUID) {
300     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
301     return VMI != GUIDToValueIdMap.end();
302   }
303   unsigned getValueId(GlobalValue::GUID ValGUID) {
304     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
305     // If this GUID doesn't have an entry, assign one.
306     if (VMI == GUIDToValueIdMap.end()) {
307       GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
308       return GlobalValueId;
309     } else {
310       return VMI->second;
311     }
312   }
313   unsigned popValueId(GlobalValue::GUID ValGUID) {
314     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
315     assert(VMI != GUIDToValueIdMap.end());
316     unsigned ValueId = VMI->second;
317     GUIDToValueIdMap.erase(VMI);
318     return ValueId;
319   }
320   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
321 };
322 
323 static unsigned getEncodedCastOpcode(unsigned Opcode) {
324   switch (Opcode) {
325   default: llvm_unreachable("Unknown cast instruction!");
326   case Instruction::Trunc   : return bitc::CAST_TRUNC;
327   case Instruction::ZExt    : return bitc::CAST_ZEXT;
328   case Instruction::SExt    : return bitc::CAST_SEXT;
329   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
330   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
331   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
332   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
333   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
334   case Instruction::FPExt   : return bitc::CAST_FPEXT;
335   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
336   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
337   case Instruction::BitCast : return bitc::CAST_BITCAST;
338   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
339   }
340 }
341 
342 static unsigned getEncodedBinaryOpcode(unsigned Opcode) {
343   switch (Opcode) {
344   default: llvm_unreachable("Unknown binary instruction!");
345   case Instruction::Add:
346   case Instruction::FAdd: return bitc::BINOP_ADD;
347   case Instruction::Sub:
348   case Instruction::FSub: return bitc::BINOP_SUB;
349   case Instruction::Mul:
350   case Instruction::FMul: return bitc::BINOP_MUL;
351   case Instruction::UDiv: return bitc::BINOP_UDIV;
352   case Instruction::FDiv:
353   case Instruction::SDiv: return bitc::BINOP_SDIV;
354   case Instruction::URem: return bitc::BINOP_UREM;
355   case Instruction::FRem:
356   case Instruction::SRem: return bitc::BINOP_SREM;
357   case Instruction::Shl:  return bitc::BINOP_SHL;
358   case Instruction::LShr: return bitc::BINOP_LSHR;
359   case Instruction::AShr: return bitc::BINOP_ASHR;
360   case Instruction::And:  return bitc::BINOP_AND;
361   case Instruction::Or:   return bitc::BINOP_OR;
362   case Instruction::Xor:  return bitc::BINOP_XOR;
363   }
364 }
365 
366 static unsigned getEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
367   switch (Op) {
368   default: llvm_unreachable("Unknown RMW operation!");
369   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
370   case AtomicRMWInst::Add: return bitc::RMW_ADD;
371   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
372   case AtomicRMWInst::And: return bitc::RMW_AND;
373   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
374   case AtomicRMWInst::Or: return bitc::RMW_OR;
375   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
376   case AtomicRMWInst::Max: return bitc::RMW_MAX;
377   case AtomicRMWInst::Min: return bitc::RMW_MIN;
378   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
379   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
380   }
381 }
382 
383 static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
384   switch (Ordering) {
385   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
386   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
387   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
388   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
389   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
390   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
391   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
392   }
393   llvm_unreachable("Invalid ordering");
394 }
395 
396 static unsigned getEncodedSynchScope(SynchronizationScope SynchScope) {
397   switch (SynchScope) {
398   case SingleThread: return bitc::SYNCHSCOPE_SINGLETHREAD;
399   case CrossThread: return bitc::SYNCHSCOPE_CROSSTHREAD;
400   }
401   llvm_unreachable("Invalid synch scope");
402 }
403 
404 void ModuleBitcodeWriter::writeStringRecord(unsigned Code, StringRef Str,
405                                             unsigned AbbrevToUse) {
406   SmallVector<unsigned, 64> Vals;
407 
408   // Code: [strchar x N]
409   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
410     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
411       AbbrevToUse = 0;
412     Vals.push_back(Str[i]);
413   }
414 
415   // Emit the finished record.
416   stream().EmitRecord(Code, Vals, AbbrevToUse);
417 }
418 
419 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
420   switch (Kind) {
421   case Attribute::Alignment:
422     return bitc::ATTR_KIND_ALIGNMENT;
423   case Attribute::AllocSize:
424     return bitc::ATTR_KIND_ALLOC_SIZE;
425   case Attribute::AlwaysInline:
426     return bitc::ATTR_KIND_ALWAYS_INLINE;
427   case Attribute::ArgMemOnly:
428     return bitc::ATTR_KIND_ARGMEMONLY;
429   case Attribute::Builtin:
430     return bitc::ATTR_KIND_BUILTIN;
431   case Attribute::ByVal:
432     return bitc::ATTR_KIND_BY_VAL;
433   case Attribute::Convergent:
434     return bitc::ATTR_KIND_CONVERGENT;
435   case Attribute::InAlloca:
436     return bitc::ATTR_KIND_IN_ALLOCA;
437   case Attribute::Cold:
438     return bitc::ATTR_KIND_COLD;
439   case Attribute::InaccessibleMemOnly:
440     return bitc::ATTR_KIND_INACCESSIBLEMEM_ONLY;
441   case Attribute::InaccessibleMemOrArgMemOnly:
442     return bitc::ATTR_KIND_INACCESSIBLEMEM_OR_ARGMEMONLY;
443   case Attribute::InlineHint:
444     return bitc::ATTR_KIND_INLINE_HINT;
445   case Attribute::InReg:
446     return bitc::ATTR_KIND_IN_REG;
447   case Attribute::JumpTable:
448     return bitc::ATTR_KIND_JUMP_TABLE;
449   case Attribute::MinSize:
450     return bitc::ATTR_KIND_MIN_SIZE;
451   case Attribute::Naked:
452     return bitc::ATTR_KIND_NAKED;
453   case Attribute::Nest:
454     return bitc::ATTR_KIND_NEST;
455   case Attribute::NoAlias:
456     return bitc::ATTR_KIND_NO_ALIAS;
457   case Attribute::NoBuiltin:
458     return bitc::ATTR_KIND_NO_BUILTIN;
459   case Attribute::NoCapture:
460     return bitc::ATTR_KIND_NO_CAPTURE;
461   case Attribute::NoDuplicate:
462     return bitc::ATTR_KIND_NO_DUPLICATE;
463   case Attribute::NoImplicitFloat:
464     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
465   case Attribute::NoInline:
466     return bitc::ATTR_KIND_NO_INLINE;
467   case Attribute::NoRecurse:
468     return bitc::ATTR_KIND_NO_RECURSE;
469   case Attribute::NonLazyBind:
470     return bitc::ATTR_KIND_NON_LAZY_BIND;
471   case Attribute::NonNull:
472     return bitc::ATTR_KIND_NON_NULL;
473   case Attribute::Dereferenceable:
474     return bitc::ATTR_KIND_DEREFERENCEABLE;
475   case Attribute::DereferenceableOrNull:
476     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
477   case Attribute::NoRedZone:
478     return bitc::ATTR_KIND_NO_RED_ZONE;
479   case Attribute::NoReturn:
480     return bitc::ATTR_KIND_NO_RETURN;
481   case Attribute::NoUnwind:
482     return bitc::ATTR_KIND_NO_UNWIND;
483   case Attribute::OptimizeForSize:
484     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
485   case Attribute::OptimizeNone:
486     return bitc::ATTR_KIND_OPTIMIZE_NONE;
487   case Attribute::ReadNone:
488     return bitc::ATTR_KIND_READ_NONE;
489   case Attribute::ReadOnly:
490     return bitc::ATTR_KIND_READ_ONLY;
491   case Attribute::Returned:
492     return bitc::ATTR_KIND_RETURNED;
493   case Attribute::ReturnsTwice:
494     return bitc::ATTR_KIND_RETURNS_TWICE;
495   case Attribute::SExt:
496     return bitc::ATTR_KIND_S_EXT;
497   case Attribute::StackAlignment:
498     return bitc::ATTR_KIND_STACK_ALIGNMENT;
499   case Attribute::StackProtect:
500     return bitc::ATTR_KIND_STACK_PROTECT;
501   case Attribute::StackProtectReq:
502     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
503   case Attribute::StackProtectStrong:
504     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
505   case Attribute::SafeStack:
506     return bitc::ATTR_KIND_SAFESTACK;
507   case Attribute::StructRet:
508     return bitc::ATTR_KIND_STRUCT_RET;
509   case Attribute::SanitizeAddress:
510     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
511   case Attribute::SanitizeThread:
512     return bitc::ATTR_KIND_SANITIZE_THREAD;
513   case Attribute::SanitizeMemory:
514     return bitc::ATTR_KIND_SANITIZE_MEMORY;
515   case Attribute::SwiftError:
516     return bitc::ATTR_KIND_SWIFT_ERROR;
517   case Attribute::SwiftSelf:
518     return bitc::ATTR_KIND_SWIFT_SELF;
519   case Attribute::UWTable:
520     return bitc::ATTR_KIND_UW_TABLE;
521   case Attribute::ZExt:
522     return bitc::ATTR_KIND_Z_EXT;
523   case Attribute::EndAttrKinds:
524     llvm_unreachable("Can not encode end-attribute kinds marker.");
525   case Attribute::None:
526     llvm_unreachable("Can not encode none-attribute.");
527   }
528 
529   llvm_unreachable("Trying to encode unknown attribute");
530 }
531 
532 void ModuleBitcodeWriter::writeAttributeGroupTable() {
533   const std::vector<AttributeSet> &AttrGrps = VE.getAttributeGroups();
534   if (AttrGrps.empty()) return;
535 
536   stream().EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
537 
538   SmallVector<uint64_t, 64> Record;
539   for (unsigned i = 0, e = AttrGrps.size(); i != e; ++i) {
540     AttributeSet AS = AttrGrps[i];
541     for (unsigned i = 0, e = AS.getNumSlots(); i != e; ++i) {
542       AttributeSet A = AS.getSlotAttributes(i);
543 
544       Record.push_back(VE.getAttributeGroupID(A));
545       Record.push_back(AS.getSlotIndex(i));
546 
547       for (AttributeSet::iterator I = AS.begin(0), E = AS.end(0);
548            I != E; ++I) {
549         Attribute Attr = *I;
550         if (Attr.isEnumAttribute()) {
551           Record.push_back(0);
552           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
553         } else if (Attr.isIntAttribute()) {
554           Record.push_back(1);
555           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
556           Record.push_back(Attr.getValueAsInt());
557         } else {
558           StringRef Kind = Attr.getKindAsString();
559           StringRef Val = Attr.getValueAsString();
560 
561           Record.push_back(Val.empty() ? 3 : 4);
562           Record.append(Kind.begin(), Kind.end());
563           Record.push_back(0);
564           if (!Val.empty()) {
565             Record.append(Val.begin(), Val.end());
566             Record.push_back(0);
567           }
568         }
569       }
570 
571       stream().EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
572       Record.clear();
573     }
574   }
575 
576   stream().ExitBlock();
577 }
578 
579 void ModuleBitcodeWriter::writeAttributeTable() {
580   const std::vector<AttributeSet> &Attrs = VE.getAttributes();
581   if (Attrs.empty()) return;
582 
583   stream().EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
584 
585   SmallVector<uint64_t, 64> Record;
586   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
587     const AttributeSet &A = Attrs[i];
588     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i)
589       Record.push_back(VE.getAttributeGroupID(A.getSlotAttributes(i)));
590 
591     stream().EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
592     Record.clear();
593   }
594 
595   stream().ExitBlock();
596 }
597 
598 /// WriteTypeTable - Write out the type table for a module.
599 void ModuleBitcodeWriter::writeTypeTable() {
600   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
601 
602   stream().EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
603   SmallVector<uint64_t, 64> TypeVals;
604 
605   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
606 
607   // Abbrev for TYPE_CODE_POINTER.
608   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
609   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
610   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
611   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
612   unsigned PtrAbbrev = stream().EmitAbbrev(Abbv);
613 
614   // Abbrev for TYPE_CODE_FUNCTION.
615   Abbv = new BitCodeAbbrev();
616   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
617   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
618   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
619   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
620 
621   unsigned FunctionAbbrev = stream().EmitAbbrev(Abbv);
622 
623   // Abbrev for TYPE_CODE_STRUCT_ANON.
624   Abbv = new BitCodeAbbrev();
625   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
626   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
627   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
628   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
629 
630   unsigned StructAnonAbbrev = stream().EmitAbbrev(Abbv);
631 
632   // Abbrev for TYPE_CODE_STRUCT_NAME.
633   Abbv = new BitCodeAbbrev();
634   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
635   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
636   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
637   unsigned StructNameAbbrev = stream().EmitAbbrev(Abbv);
638 
639   // Abbrev for TYPE_CODE_STRUCT_NAMED.
640   Abbv = new BitCodeAbbrev();
641   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
642   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
643   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
644   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
645 
646   unsigned StructNamedAbbrev = stream().EmitAbbrev(Abbv);
647 
648   // Abbrev for TYPE_CODE_ARRAY.
649   Abbv = new BitCodeAbbrev();
650   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
651   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
652   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
653 
654   unsigned ArrayAbbrev = stream().EmitAbbrev(Abbv);
655 
656   // Emit an entry count so the reader can reserve space.
657   TypeVals.push_back(TypeList.size());
658   stream().EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
659   TypeVals.clear();
660 
661   // Loop over all of the types, emitting each in turn.
662   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
663     Type *T = TypeList[i];
664     int AbbrevToUse = 0;
665     unsigned Code = 0;
666 
667     switch (T->getTypeID()) {
668     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
669     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
670     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
671     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
672     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
673     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
674     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
675     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
676     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
677     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
678     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
679     case Type::IntegerTyID:
680       // INTEGER: [width]
681       Code = bitc::TYPE_CODE_INTEGER;
682       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
683       break;
684     case Type::PointerTyID: {
685       PointerType *PTy = cast<PointerType>(T);
686       // POINTER: [pointee type, address space]
687       Code = bitc::TYPE_CODE_POINTER;
688       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
689       unsigned AddressSpace = PTy->getAddressSpace();
690       TypeVals.push_back(AddressSpace);
691       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
692       break;
693     }
694     case Type::FunctionTyID: {
695       FunctionType *FT = cast<FunctionType>(T);
696       // FUNCTION: [isvararg, retty, paramty x N]
697       Code = bitc::TYPE_CODE_FUNCTION;
698       TypeVals.push_back(FT->isVarArg());
699       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
700       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
701         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
702       AbbrevToUse = FunctionAbbrev;
703       break;
704     }
705     case Type::StructTyID: {
706       StructType *ST = cast<StructType>(T);
707       // STRUCT: [ispacked, eltty x N]
708       TypeVals.push_back(ST->isPacked());
709       // Output all of the element types.
710       for (StructType::element_iterator I = ST->element_begin(),
711            E = ST->element_end(); I != E; ++I)
712         TypeVals.push_back(VE.getTypeID(*I));
713 
714       if (ST->isLiteral()) {
715         Code = bitc::TYPE_CODE_STRUCT_ANON;
716         AbbrevToUse = StructAnonAbbrev;
717       } else {
718         if (ST->isOpaque()) {
719           Code = bitc::TYPE_CODE_OPAQUE;
720         } else {
721           Code = bitc::TYPE_CODE_STRUCT_NAMED;
722           AbbrevToUse = StructNamedAbbrev;
723         }
724 
725         // Emit the name if it is present.
726         if (!ST->getName().empty())
727           writeStringRecord(bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
728                             StructNameAbbrev);
729       }
730       break;
731     }
732     case Type::ArrayTyID: {
733       ArrayType *AT = cast<ArrayType>(T);
734       // ARRAY: [numelts, eltty]
735       Code = bitc::TYPE_CODE_ARRAY;
736       TypeVals.push_back(AT->getNumElements());
737       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
738       AbbrevToUse = ArrayAbbrev;
739       break;
740     }
741     case Type::VectorTyID: {
742       VectorType *VT = cast<VectorType>(T);
743       // VECTOR [numelts, eltty]
744       Code = bitc::TYPE_CODE_VECTOR;
745       TypeVals.push_back(VT->getNumElements());
746       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
747       break;
748     }
749     }
750 
751     // Emit the finished record.
752     stream().EmitRecord(Code, TypeVals, AbbrevToUse);
753     TypeVals.clear();
754   }
755 
756   stream().ExitBlock();
757 }
758 
759 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
760   switch (Linkage) {
761   case GlobalValue::ExternalLinkage:
762     return 0;
763   case GlobalValue::WeakAnyLinkage:
764     return 16;
765   case GlobalValue::AppendingLinkage:
766     return 2;
767   case GlobalValue::InternalLinkage:
768     return 3;
769   case GlobalValue::LinkOnceAnyLinkage:
770     return 18;
771   case GlobalValue::ExternalWeakLinkage:
772     return 7;
773   case GlobalValue::CommonLinkage:
774     return 8;
775   case GlobalValue::PrivateLinkage:
776     return 9;
777   case GlobalValue::WeakODRLinkage:
778     return 17;
779   case GlobalValue::LinkOnceODRLinkage:
780     return 19;
781   case GlobalValue::AvailableExternallyLinkage:
782     return 12;
783   }
784   llvm_unreachable("Invalid linkage");
785 }
786 
787 static unsigned getEncodedLinkage(const GlobalValue &GV) {
788   return getEncodedLinkage(GV.getLinkage());
789 }
790 
791 static unsigned getEncodedVisibility(const GlobalValue &GV) {
792   switch (GV.getVisibility()) {
793   case GlobalValue::DefaultVisibility:   return 0;
794   case GlobalValue::HiddenVisibility:    return 1;
795   case GlobalValue::ProtectedVisibility: return 2;
796   }
797   llvm_unreachable("Invalid visibility");
798 }
799 
800 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
801   switch (GV.getDLLStorageClass()) {
802   case GlobalValue::DefaultStorageClass:   return 0;
803   case GlobalValue::DLLImportStorageClass: return 1;
804   case GlobalValue::DLLExportStorageClass: return 2;
805   }
806   llvm_unreachable("Invalid DLL storage class");
807 }
808 
809 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
810   switch (GV.getThreadLocalMode()) {
811     case GlobalVariable::NotThreadLocal:         return 0;
812     case GlobalVariable::GeneralDynamicTLSModel: return 1;
813     case GlobalVariable::LocalDynamicTLSModel:   return 2;
814     case GlobalVariable::InitialExecTLSModel:    return 3;
815     case GlobalVariable::LocalExecTLSModel:      return 4;
816   }
817   llvm_unreachable("Invalid TLS model");
818 }
819 
820 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
821   switch (C.getSelectionKind()) {
822   case Comdat::Any:
823     return bitc::COMDAT_SELECTION_KIND_ANY;
824   case Comdat::ExactMatch:
825     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
826   case Comdat::Largest:
827     return bitc::COMDAT_SELECTION_KIND_LARGEST;
828   case Comdat::NoDuplicates:
829     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
830   case Comdat::SameSize:
831     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
832   }
833   llvm_unreachable("Invalid selection kind");
834 }
835 
836 void ModuleBitcodeWriter::writeComdats() {
837   SmallVector<unsigned, 64> Vals;
838   for (const Comdat *C : VE.getComdats()) {
839     // COMDAT: [selection_kind, name]
840     Vals.push_back(getEncodedComdatSelectionKind(*C));
841     size_t Size = C->getName().size();
842     assert(isUInt<32>(Size));
843     Vals.push_back(Size);
844     for (char Chr : C->getName())
845       Vals.push_back((unsigned char)Chr);
846     stream().EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
847     Vals.clear();
848   }
849 }
850 
851 /// Write a record that will eventually hold the word offset of the
852 /// module-level VST. For now the offset is 0, which will be backpatched
853 /// after the real VST is written. Saves the bit offset to backpatch.
854 void BitcodeWriter::writeValueSymbolTableForwardDecl() {
855   // Write a placeholder value in for the offset of the real VST,
856   // which is written after the function blocks so that it can include
857   // the offset of each function. The placeholder offset will be
858   // updated when the real VST is written.
859   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
860   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
861   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
862   // hold the real VST offset. Must use fixed instead of VBR as we don't
863   // know how many VBR chunks to reserve ahead of time.
864   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
865   unsigned VSTOffsetAbbrev = stream().EmitAbbrev(Abbv);
866 
867   // Emit the placeholder
868   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
869   stream().EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
870 
871   // Compute and save the bit offset to the placeholder, which will be
872   // patched when the real VST is written. We can simply subtract the 32-bit
873   // fixed size from the current bit number to get the location to backpatch.
874   VSTOffsetPlaceholder = stream().GetCurrentBitNo() - 32;
875 }
876 
877 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
878 
879 /// Determine the encoding to use for the given string name and length.
880 static StringEncoding getStringEncoding(const char *Str, unsigned StrLen) {
881   bool isChar6 = true;
882   for (const char *C = Str, *E = C + StrLen; C != E; ++C) {
883     if (isChar6)
884       isChar6 = BitCodeAbbrevOp::isChar6(*C);
885     if ((unsigned char)*C & 128)
886       // don't bother scanning the rest.
887       return SE_Fixed8;
888   }
889   if (isChar6)
890     return SE_Char6;
891   else
892     return SE_Fixed7;
893 }
894 
895 /// Emit top-level description of module, including target triple, inline asm,
896 /// descriptors for global variables, and function prototype info.
897 /// Returns the bit offset to backpatch with the location of the real VST.
898 void ModuleBitcodeWriter::writeModuleInfo() {
899   // Emit various pieces of data attached to a module.
900   if (!M->getTargetTriple().empty())
901     writeStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
902                       0 /*TODO*/);
903   const std::string &DL = M->getDataLayoutStr();
904   if (!DL.empty())
905     writeStringRecord(bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
906   if (!M->getModuleInlineAsm().empty())
907     writeStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
908                       0 /*TODO*/);
909 
910   // Emit information about sections and GC, computing how many there are. Also
911   // compute the maximum alignment value.
912   std::map<std::string, unsigned> SectionMap;
913   std::map<std::string, unsigned> GCMap;
914   unsigned MaxAlignment = 0;
915   unsigned MaxGlobalType = 0;
916   for (const GlobalValue &GV : M->globals()) {
917     MaxAlignment = std::max(MaxAlignment, GV.getAlignment());
918     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
919     if (GV.hasSection()) {
920       // Give section names unique ID's.
921       unsigned &Entry = SectionMap[GV.getSection()];
922       if (!Entry) {
923         writeStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
924                           0 /*TODO*/);
925         Entry = SectionMap.size();
926       }
927     }
928   }
929   for (const Function &F : *M) {
930     MaxAlignment = std::max(MaxAlignment, F.getAlignment());
931     if (F.hasSection()) {
932       // Give section names unique ID's.
933       unsigned &Entry = SectionMap[F.getSection()];
934       if (!Entry) {
935         writeStringRecord(bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
936                           0 /*TODO*/);
937         Entry = SectionMap.size();
938       }
939     }
940     if (F.hasGC()) {
941       // Same for GC names.
942       unsigned &Entry = GCMap[F.getGC()];
943       if (!Entry) {
944         writeStringRecord(bitc::MODULE_CODE_GCNAME, F.getGC(), 0 /*TODO*/);
945         Entry = GCMap.size();
946       }
947     }
948   }
949 
950   // Emit abbrev for globals, now that we know # sections and max alignment.
951   unsigned SimpleGVarAbbrev = 0;
952   if (!M->global_empty()) {
953     // Add an abbrev for common globals with no visibility or thread localness.
954     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
955     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
956     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
957                               Log2_32_Ceil(MaxGlobalType+1)));
958     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
959                                                            //| explicitType << 1
960                                                            //| constant
961     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
962     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
963     if (MaxAlignment == 0)                                 // Alignment.
964       Abbv->Add(BitCodeAbbrevOp(0));
965     else {
966       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
967       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
968                                Log2_32_Ceil(MaxEncAlignment+1)));
969     }
970     if (SectionMap.empty())                                    // Section.
971       Abbv->Add(BitCodeAbbrevOp(0));
972     else
973       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
974                                Log2_32_Ceil(SectionMap.size()+1)));
975     // Don't bother emitting vis + thread local.
976     SimpleGVarAbbrev = stream().EmitAbbrev(Abbv);
977   }
978 
979   // Emit the global variable information.
980   SmallVector<unsigned, 64> Vals;
981   for (const GlobalVariable &GV : M->globals()) {
982     unsigned AbbrevToUse = 0;
983 
984     // GLOBALVAR: [type, isconst, initid,
985     //             linkage, alignment, section, visibility, threadlocal,
986     //             unnamed_addr, externally_initialized, dllstorageclass,
987     //             comdat]
988     Vals.push_back(VE.getTypeID(GV.getValueType()));
989     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
990     Vals.push_back(GV.isDeclaration() ? 0 :
991                    (VE.getValueID(GV.getInitializer()) + 1));
992     Vals.push_back(getEncodedLinkage(GV));
993     Vals.push_back(Log2_32(GV.getAlignment())+1);
994     Vals.push_back(GV.hasSection() ? SectionMap[GV.getSection()] : 0);
995     if (GV.isThreadLocal() ||
996         GV.getVisibility() != GlobalValue::DefaultVisibility ||
997         GV.hasUnnamedAddr() || GV.isExternallyInitialized() ||
998         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
999         GV.hasComdat()) {
1000       Vals.push_back(getEncodedVisibility(GV));
1001       Vals.push_back(getEncodedThreadLocalMode(GV));
1002       Vals.push_back(GV.hasUnnamedAddr());
1003       Vals.push_back(GV.isExternallyInitialized());
1004       Vals.push_back(getEncodedDLLStorageClass(GV));
1005       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1006     } else {
1007       AbbrevToUse = SimpleGVarAbbrev;
1008     }
1009 
1010     stream().EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1011     Vals.clear();
1012   }
1013 
1014   // Emit the function proto information.
1015   for (const Function &F : *M) {
1016     // FUNCTION:  [type, callingconv, isproto, linkage, paramattrs, alignment,
1017     //             section, visibility, gc, unnamed_addr, prologuedata,
1018     //             dllstorageclass, comdat, prefixdata, personalityfn]
1019     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1020     Vals.push_back(F.getCallingConv());
1021     Vals.push_back(F.isDeclaration());
1022     Vals.push_back(getEncodedLinkage(F));
1023     Vals.push_back(VE.getAttributeID(F.getAttributes()));
1024     Vals.push_back(Log2_32(F.getAlignment())+1);
1025     Vals.push_back(F.hasSection() ? SectionMap[F.getSection()] : 0);
1026     Vals.push_back(getEncodedVisibility(F));
1027     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1028     Vals.push_back(F.hasUnnamedAddr());
1029     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1030                                        : 0);
1031     Vals.push_back(getEncodedDLLStorageClass(F));
1032     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1033     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1034                                      : 0);
1035     Vals.push_back(
1036         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1037 
1038     unsigned AbbrevToUse = 0;
1039     stream().EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1040     Vals.clear();
1041   }
1042 
1043   // Emit the alias information.
1044   for (const GlobalAlias &A : M->aliases()) {
1045     // ALIAS: [alias type, aliasee val#, linkage, visibility]
1046     Vals.push_back(VE.getTypeID(A.getValueType()));
1047     Vals.push_back(A.getType()->getAddressSpace());
1048     Vals.push_back(VE.getValueID(A.getAliasee()));
1049     Vals.push_back(getEncodedLinkage(A));
1050     Vals.push_back(getEncodedVisibility(A));
1051     Vals.push_back(getEncodedDLLStorageClass(A));
1052     Vals.push_back(getEncodedThreadLocalMode(A));
1053     Vals.push_back(A.hasUnnamedAddr());
1054     unsigned AbbrevToUse = 0;
1055     stream().EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1056     Vals.clear();
1057   }
1058 
1059   // Emit the ifunc information.
1060   for (const GlobalIFunc &I : M->ifuncs()) {
1061     // IFUNC: [ifunc type, address space, resolver val#, linkage, visibility]
1062     Vals.push_back(VE.getTypeID(I.getValueType()));
1063     Vals.push_back(I.getType()->getAddressSpace());
1064     Vals.push_back(VE.getValueID(I.getResolver()));
1065     Vals.push_back(getEncodedLinkage(I));
1066     Vals.push_back(getEncodedVisibility(I));
1067     stream().EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1068     Vals.clear();
1069   }
1070 
1071   // Emit the module's source file name.
1072   {
1073     StringEncoding Bits = getStringEncoding(M->getSourceFileName().data(),
1074                                             M->getSourceFileName().size());
1075     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1076     if (Bits == SE_Char6)
1077       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1078     else if (Bits == SE_Fixed7)
1079       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1080 
1081     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1082     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1083     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1084     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1085     Abbv->Add(AbbrevOpToUse);
1086     unsigned FilenameAbbrev = stream().EmitAbbrev(Abbv);
1087 
1088     for (const auto P : M->getSourceFileName())
1089       Vals.push_back((unsigned char)P);
1090 
1091     // Emit the finished record.
1092     stream().EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals,
1093                         FilenameAbbrev);
1094     Vals.clear();
1095   }
1096 
1097   // If we have a VST, write the VSTOFFSET record placeholder.
1098   if (M->getValueSymbolTable().empty())
1099     return;
1100   writeValueSymbolTableForwardDecl();
1101 }
1102 
1103 static uint64_t getOptimizationFlags(const Value *V) {
1104   uint64_t Flags = 0;
1105 
1106   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1107     if (OBO->hasNoSignedWrap())
1108       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1109     if (OBO->hasNoUnsignedWrap())
1110       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1111   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1112     if (PEO->isExact())
1113       Flags |= 1 << bitc::PEO_EXACT;
1114   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1115     if (FPMO->hasUnsafeAlgebra())
1116       Flags |= FastMathFlags::UnsafeAlgebra;
1117     if (FPMO->hasNoNaNs())
1118       Flags |= FastMathFlags::NoNaNs;
1119     if (FPMO->hasNoInfs())
1120       Flags |= FastMathFlags::NoInfs;
1121     if (FPMO->hasNoSignedZeros())
1122       Flags |= FastMathFlags::NoSignedZeros;
1123     if (FPMO->hasAllowReciprocal())
1124       Flags |= FastMathFlags::AllowReciprocal;
1125   }
1126 
1127   return Flags;
1128 }
1129 
1130 void ModuleBitcodeWriter::writeValueAsMetadata(
1131     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1132   // Mimic an MDNode with a value as one operand.
1133   Value *V = MD->getValue();
1134   Record.push_back(VE.getTypeID(V->getType()));
1135   Record.push_back(VE.getValueID(V));
1136   stream().EmitRecord(bitc::METADATA_VALUE, Record, 0);
1137   Record.clear();
1138 }
1139 
1140 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1141                                        SmallVectorImpl<uint64_t> &Record,
1142                                        unsigned Abbrev) {
1143   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1144     Metadata *MD = N->getOperand(i);
1145     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1146            "Unexpected function-local metadata");
1147     Record.push_back(VE.getMetadataOrNullID(MD));
1148   }
1149   stream().EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1150                                       : bitc::METADATA_NODE,
1151                       Record, Abbrev);
1152   Record.clear();
1153 }
1154 
1155 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1156   // Assume the column is usually under 128, and always output the inlined-at
1157   // location (it's never more expensive than building an array size 1).
1158   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1159   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1160   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1161   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1162   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1163   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1164   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1165   return stream().EmitAbbrev(Abbv);
1166 }
1167 
1168 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1169                                           SmallVectorImpl<uint64_t> &Record,
1170                                           unsigned &Abbrev) {
1171   if (!Abbrev)
1172     Abbrev = createDILocationAbbrev();
1173 
1174   Record.push_back(N->isDistinct());
1175   Record.push_back(N->getLine());
1176   Record.push_back(N->getColumn());
1177   Record.push_back(VE.getMetadataID(N->getScope()));
1178   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1179 
1180   stream().EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1181   Record.clear();
1182 }
1183 
1184 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1185   // Assume the column is usually under 128, and always output the inlined-at
1186   // location (it's never more expensive than building an array size 1).
1187   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1188   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1189   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1190   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1191   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1192   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1193   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1194   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1195   return stream().EmitAbbrev(Abbv);
1196 }
1197 
1198 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1199                                              SmallVectorImpl<uint64_t> &Record,
1200                                              unsigned &Abbrev) {
1201   if (!Abbrev)
1202     Abbrev = createGenericDINodeAbbrev();
1203 
1204   Record.push_back(N->isDistinct());
1205   Record.push_back(N->getTag());
1206   Record.push_back(0); // Per-tag version field; unused for now.
1207 
1208   for (auto &I : N->operands())
1209     Record.push_back(VE.getMetadataOrNullID(I));
1210 
1211   stream().EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1212   Record.clear();
1213 }
1214 
1215 static uint64_t rotateSign(int64_t I) {
1216   uint64_t U = I;
1217   return I < 0 ? ~(U << 1) : U << 1;
1218 }
1219 
1220 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1221                                           SmallVectorImpl<uint64_t> &Record,
1222                                           unsigned Abbrev) {
1223   Record.push_back(N->isDistinct());
1224   Record.push_back(N->getCount());
1225   Record.push_back(rotateSign(N->getLowerBound()));
1226 
1227   stream().EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1228   Record.clear();
1229 }
1230 
1231 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1232                                             SmallVectorImpl<uint64_t> &Record,
1233                                             unsigned Abbrev) {
1234   Record.push_back(N->isDistinct());
1235   Record.push_back(rotateSign(N->getValue()));
1236   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1237 
1238   stream().EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1239   Record.clear();
1240 }
1241 
1242 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1243                                            SmallVectorImpl<uint64_t> &Record,
1244                                            unsigned Abbrev) {
1245   Record.push_back(N->isDistinct());
1246   Record.push_back(N->getTag());
1247   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1248   Record.push_back(N->getSizeInBits());
1249   Record.push_back(N->getAlignInBits());
1250   Record.push_back(N->getEncoding());
1251 
1252   stream().EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1253   Record.clear();
1254 }
1255 
1256 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1257                                              SmallVectorImpl<uint64_t> &Record,
1258                                              unsigned Abbrev) {
1259   Record.push_back(N->isDistinct());
1260   Record.push_back(N->getTag());
1261   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1262   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1263   Record.push_back(N->getLine());
1264   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1265   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1266   Record.push_back(N->getSizeInBits());
1267   Record.push_back(N->getAlignInBits());
1268   Record.push_back(N->getOffsetInBits());
1269   Record.push_back(N->getFlags());
1270   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1271 
1272   stream().EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1273   Record.clear();
1274 }
1275 
1276 void ModuleBitcodeWriter::writeDICompositeType(
1277     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1278     unsigned Abbrev) {
1279   Record.push_back(N->isDistinct());
1280   Record.push_back(N->getTag());
1281   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1282   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1283   Record.push_back(N->getLine());
1284   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1285   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1286   Record.push_back(N->getSizeInBits());
1287   Record.push_back(N->getAlignInBits());
1288   Record.push_back(N->getOffsetInBits());
1289   Record.push_back(N->getFlags());
1290   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1291   Record.push_back(N->getRuntimeLang());
1292   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1293   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1294   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1295 
1296   stream().EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1297   Record.clear();
1298 }
1299 
1300 void ModuleBitcodeWriter::writeDISubroutineType(
1301     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1302     unsigned Abbrev) {
1303   Record.push_back(N->isDistinct());
1304   Record.push_back(N->getFlags());
1305   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1306 
1307   stream().EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1308   Record.clear();
1309 }
1310 
1311 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1312                                       SmallVectorImpl<uint64_t> &Record,
1313                                       unsigned Abbrev) {
1314   Record.push_back(N->isDistinct());
1315   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1316   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1317 
1318   stream().EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1319   Record.clear();
1320 }
1321 
1322 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1323                                              SmallVectorImpl<uint64_t> &Record,
1324                                              unsigned Abbrev) {
1325   assert(N->isDistinct() && "Expected distinct compile units");
1326   Record.push_back(/* IsDistinct */ true);
1327   Record.push_back(N->getSourceLanguage());
1328   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1329   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1330   Record.push_back(N->isOptimized());
1331   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1332   Record.push_back(N->getRuntimeVersion());
1333   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1334   Record.push_back(N->getEmissionKind());
1335   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1336   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1337   Record.push_back(/* subprograms */ 0);
1338   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1339   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1340   Record.push_back(N->getDWOId());
1341   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1342 
1343   stream().EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1344   Record.clear();
1345 }
1346 
1347 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1348                                             SmallVectorImpl<uint64_t> &Record,
1349                                             unsigned Abbrev) {
1350   Record.push_back(N->isDistinct());
1351   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1352   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1353   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1354   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1355   Record.push_back(N->getLine());
1356   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1357   Record.push_back(N->isLocalToUnit());
1358   Record.push_back(N->isDefinition());
1359   Record.push_back(N->getScopeLine());
1360   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1361   Record.push_back(N->getVirtuality());
1362   Record.push_back(N->getVirtualIndex());
1363   Record.push_back(N->getFlags());
1364   Record.push_back(N->isOptimized());
1365   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1366   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1367   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1368   Record.push_back(VE.getMetadataOrNullID(N->getVariables().get()));
1369 
1370   stream().EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1371   Record.clear();
1372 }
1373 
1374 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1375                                               SmallVectorImpl<uint64_t> &Record,
1376                                               unsigned Abbrev) {
1377   Record.push_back(N->isDistinct());
1378   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1379   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1380   Record.push_back(N->getLine());
1381   Record.push_back(N->getColumn());
1382 
1383   stream().EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1384   Record.clear();
1385 }
1386 
1387 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1388     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1389     unsigned Abbrev) {
1390   Record.push_back(N->isDistinct());
1391   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1392   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1393   Record.push_back(N->getDiscriminator());
1394 
1395   stream().EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1396   Record.clear();
1397 }
1398 
1399 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1400                                            SmallVectorImpl<uint64_t> &Record,
1401                                            unsigned Abbrev) {
1402   Record.push_back(N->isDistinct());
1403   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1404   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1405   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1406   Record.push_back(N->getLine());
1407 
1408   stream().EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1409   Record.clear();
1410 }
1411 
1412 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1413                                        SmallVectorImpl<uint64_t> &Record,
1414                                        unsigned Abbrev) {
1415   Record.push_back(N->isDistinct());
1416   Record.push_back(N->getMacinfoType());
1417   Record.push_back(N->getLine());
1418   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1419   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1420 
1421   stream().EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1422   Record.clear();
1423 }
1424 
1425 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1426                                            SmallVectorImpl<uint64_t> &Record,
1427                                            unsigned Abbrev) {
1428   Record.push_back(N->isDistinct());
1429   Record.push_back(N->getMacinfoType());
1430   Record.push_back(N->getLine());
1431   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1432   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1433 
1434   stream().EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1435   Record.clear();
1436 }
1437 
1438 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1439                                         SmallVectorImpl<uint64_t> &Record,
1440                                         unsigned Abbrev) {
1441   Record.push_back(N->isDistinct());
1442   for (auto &I : N->operands())
1443     Record.push_back(VE.getMetadataOrNullID(I));
1444 
1445   stream().EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1446   Record.clear();
1447 }
1448 
1449 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1450     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1451     unsigned Abbrev) {
1452   Record.push_back(N->isDistinct());
1453   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1454   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1455 
1456   stream().EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1457   Record.clear();
1458 }
1459 
1460 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1461     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1462     unsigned Abbrev) {
1463   Record.push_back(N->isDistinct());
1464   Record.push_back(N->getTag());
1465   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1466   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1467   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1468 
1469   stream().EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1470   Record.clear();
1471 }
1472 
1473 void ModuleBitcodeWriter::writeDIGlobalVariable(
1474     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1475     unsigned Abbrev) {
1476   Record.push_back(N->isDistinct());
1477   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1478   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1479   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1480   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1481   Record.push_back(N->getLine());
1482   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1483   Record.push_back(N->isLocalToUnit());
1484   Record.push_back(N->isDefinition());
1485   Record.push_back(VE.getMetadataOrNullID(N->getRawVariable()));
1486   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1487 
1488   stream().EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1489   Record.clear();
1490 }
1491 
1492 void ModuleBitcodeWriter::writeDILocalVariable(
1493     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
1494     unsigned Abbrev) {
1495   Record.push_back(N->isDistinct());
1496   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1497   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1498   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1499   Record.push_back(N->getLine());
1500   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1501   Record.push_back(N->getArg());
1502   Record.push_back(N->getFlags());
1503 
1504   stream().EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1505   Record.clear();
1506 }
1507 
1508 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
1509                                             SmallVectorImpl<uint64_t> &Record,
1510                                             unsigned Abbrev) {
1511   Record.reserve(N->getElements().size() + 1);
1512 
1513   Record.push_back(N->isDistinct());
1514   Record.append(N->elements_begin(), N->elements_end());
1515 
1516   stream().EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
1517   Record.clear();
1518 }
1519 
1520 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
1521                                               SmallVectorImpl<uint64_t> &Record,
1522                                               unsigned Abbrev) {
1523   Record.push_back(N->isDistinct());
1524   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1525   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1526   Record.push_back(N->getLine());
1527   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
1528   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
1529   Record.push_back(N->getAttributes());
1530   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1531 
1532   stream().EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
1533   Record.clear();
1534 }
1535 
1536 void ModuleBitcodeWriter::writeDIImportedEntity(
1537     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
1538     unsigned Abbrev) {
1539   Record.push_back(N->isDistinct());
1540   Record.push_back(N->getTag());
1541   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1542   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
1543   Record.push_back(N->getLine());
1544   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1545 
1546   stream().EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
1547   Record.clear();
1548 }
1549 
1550 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
1551   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1552   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
1553   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1554   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1555   return stream().EmitAbbrev(Abbv);
1556 }
1557 
1558 void ModuleBitcodeWriter::writeNamedMetadata(
1559     SmallVectorImpl<uint64_t> &Record) {
1560   if (M->named_metadata_empty())
1561     return;
1562 
1563   unsigned Abbrev = createNamedMetadataAbbrev();
1564   for (const NamedMDNode &NMD : M->named_metadata()) {
1565     // Write name.
1566     StringRef Str = NMD.getName();
1567     Record.append(Str.bytes_begin(), Str.bytes_end());
1568     stream().EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
1569     Record.clear();
1570 
1571     // Write named metadata operands.
1572     for (const MDNode *N : NMD.operands())
1573       Record.push_back(VE.getMetadataID(N));
1574     stream().EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
1575     Record.clear();
1576   }
1577 }
1578 
1579 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
1580   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1581   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
1582   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
1583   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
1584   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
1585   return stream().EmitAbbrev(Abbv);
1586 }
1587 
1588 /// Write out a record for MDString.
1589 ///
1590 /// All the metadata strings in a metadata block are emitted in a single
1591 /// record.  The sizes and strings themselves are shoved into a blob.
1592 void ModuleBitcodeWriter::writeMetadataStrings(
1593     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
1594   if (Strings.empty())
1595     return;
1596 
1597   // Start the record with the number of strings.
1598   Record.push_back(bitc::METADATA_STRINGS);
1599   Record.push_back(Strings.size());
1600 
1601   // Emit the sizes of the strings in the blob.
1602   SmallString<256> Blob;
1603   {
1604     BitstreamWriter W(Blob);
1605     for (const Metadata *MD : Strings)
1606       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
1607     W.FlushToWord();
1608   }
1609 
1610   // Add the offset to the strings to the record.
1611   Record.push_back(Blob.size());
1612 
1613   // Add the strings to the blob.
1614   for (const Metadata *MD : Strings)
1615     Blob.append(cast<MDString>(MD)->getString());
1616 
1617   // Emit the final record.
1618   stream().EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
1619   Record.clear();
1620 }
1621 
1622 void ModuleBitcodeWriter::writeMetadataRecords(
1623     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record) {
1624   if (MDs.empty())
1625     return;
1626 
1627   // Initialize MDNode abbreviations.
1628 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
1629 #include "llvm/IR/Metadata.def"
1630 
1631   for (const Metadata *MD : MDs) {
1632     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
1633       assert(N->isResolved() && "Expected forward references to be resolved");
1634 
1635       switch (N->getMetadataID()) {
1636       default:
1637         llvm_unreachable("Invalid MDNode subclass");
1638 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
1639   case Metadata::CLASS##Kind:                                                  \
1640     write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                       \
1641     continue;
1642 #include "llvm/IR/Metadata.def"
1643       }
1644     }
1645     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
1646   }
1647 }
1648 
1649 void ModuleBitcodeWriter::writeModuleMetadata() {
1650   if (!VE.hasMDs() && M->named_metadata_empty())
1651     return;
1652 
1653   stream().EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1654   SmallVector<uint64_t, 64> Record;
1655   writeMetadataStrings(VE.getMDStrings(), Record);
1656   writeMetadataRecords(VE.getNonMDStrings(), Record);
1657   writeNamedMetadata(Record);
1658   stream().ExitBlock();
1659 }
1660 
1661 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
1662   if (!VE.hasMDs())
1663     return;
1664 
1665   stream().EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1666   SmallVector<uint64_t, 64> Record;
1667   writeMetadataStrings(VE.getMDStrings(), Record);
1668   writeMetadataRecords(VE.getNonMDStrings(), Record);
1669   stream().ExitBlock();
1670 }
1671 
1672 void ModuleBitcodeWriter::writeMetadataAttachment(const Function &F) {
1673   stream().EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
1674 
1675   SmallVector<uint64_t, 64> Record;
1676 
1677   // Write metadata attachments
1678   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
1679   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
1680   F.getAllMetadata(MDs);
1681   if (!MDs.empty()) {
1682     for (const auto &I : MDs) {
1683       Record.push_back(I.first);
1684       Record.push_back(VE.getMetadataID(I.second));
1685     }
1686     stream().EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1687     Record.clear();
1688   }
1689 
1690   for (const BasicBlock &BB : F)
1691     for (const Instruction &I : BB) {
1692       MDs.clear();
1693       I.getAllMetadataOtherThanDebugLoc(MDs);
1694 
1695       // If no metadata, ignore instruction.
1696       if (MDs.empty()) continue;
1697 
1698       Record.push_back(VE.getInstructionID(&I));
1699 
1700       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1701         Record.push_back(MDs[i].first);
1702         Record.push_back(VE.getMetadataID(MDs[i].second));
1703       }
1704       stream().EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1705       Record.clear();
1706     }
1707 
1708   stream().ExitBlock();
1709 }
1710 
1711 void ModuleBitcodeWriter::writeModuleMetadataStore() {
1712   SmallVector<uint64_t, 64> Record;
1713 
1714   // Write metadata kinds
1715   // METADATA_KIND - [n x [id, name]]
1716   SmallVector<StringRef, 8> Names;
1717   M->getMDKindNames(Names);
1718 
1719   if (Names.empty()) return;
1720 
1721   stream().EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
1722 
1723   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
1724     Record.push_back(MDKindID);
1725     StringRef KName = Names[MDKindID];
1726     Record.append(KName.begin(), KName.end());
1727 
1728     stream().EmitRecord(bitc::METADATA_KIND, Record, 0);
1729     Record.clear();
1730   }
1731 
1732   stream().ExitBlock();
1733 }
1734 
1735 void ModuleBitcodeWriter::writeOperandBundleTags() {
1736   // Write metadata kinds
1737   //
1738   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
1739   //
1740   // OPERAND_BUNDLE_TAG - [strchr x N]
1741 
1742   SmallVector<StringRef, 8> Tags;
1743   M->getOperandBundleTags(Tags);
1744 
1745   if (Tags.empty())
1746     return;
1747 
1748   stream().EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
1749 
1750   SmallVector<uint64_t, 64> Record;
1751 
1752   for (auto Tag : Tags) {
1753     Record.append(Tag.begin(), Tag.end());
1754 
1755     stream().EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
1756     Record.clear();
1757   }
1758 
1759   stream().ExitBlock();
1760 }
1761 
1762 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1763   if ((int64_t)V >= 0)
1764     Vals.push_back(V << 1);
1765   else
1766     Vals.push_back((-V << 1) | 1);
1767 }
1768 
1769 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
1770                                          bool isGlobal) {
1771   if (FirstVal == LastVal) return;
1772 
1773   stream().EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
1774 
1775   unsigned AggregateAbbrev = 0;
1776   unsigned String8Abbrev = 0;
1777   unsigned CString7Abbrev = 0;
1778   unsigned CString6Abbrev = 0;
1779   // If this is a constant pool for the module, emit module-specific abbrevs.
1780   if (isGlobal) {
1781     // Abbrev for CST_CODE_AGGREGATE.
1782     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1783     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
1784     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1785     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
1786     AggregateAbbrev = stream().EmitAbbrev(Abbv);
1787 
1788     // Abbrev for CST_CODE_STRING.
1789     Abbv = new BitCodeAbbrev();
1790     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
1791     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1792     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1793     String8Abbrev = stream().EmitAbbrev(Abbv);
1794     // Abbrev for CST_CODE_CSTRING.
1795     Abbv = new BitCodeAbbrev();
1796     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1797     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1798     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1799     CString7Abbrev = stream().EmitAbbrev(Abbv);
1800     // Abbrev for CST_CODE_CSTRING.
1801     Abbv = new BitCodeAbbrev();
1802     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1803     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1804     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1805     CString6Abbrev = stream().EmitAbbrev(Abbv);
1806   }
1807 
1808   SmallVector<uint64_t, 64> Record;
1809 
1810   const ValueEnumerator::ValueList &Vals = VE.getValues();
1811   Type *LastTy = nullptr;
1812   for (unsigned i = FirstVal; i != LastVal; ++i) {
1813     const Value *V = Vals[i].first;
1814     // If we need to switch types, do so now.
1815     if (V->getType() != LastTy) {
1816       LastTy = V->getType();
1817       Record.push_back(VE.getTypeID(LastTy));
1818       stream().EmitRecord(bitc::CST_CODE_SETTYPE, Record,
1819                           CONSTANTS_SETTYPE_ABBREV);
1820       Record.clear();
1821     }
1822 
1823     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
1824       Record.push_back(unsigned(IA->hasSideEffects()) |
1825                        unsigned(IA->isAlignStack()) << 1 |
1826                        unsigned(IA->getDialect()&1) << 2);
1827 
1828       // Add the asm string.
1829       const std::string &AsmStr = IA->getAsmString();
1830       Record.push_back(AsmStr.size());
1831       Record.append(AsmStr.begin(), AsmStr.end());
1832 
1833       // Add the constraint string.
1834       const std::string &ConstraintStr = IA->getConstraintString();
1835       Record.push_back(ConstraintStr.size());
1836       Record.append(ConstraintStr.begin(), ConstraintStr.end());
1837       stream().EmitRecord(bitc::CST_CODE_INLINEASM, Record);
1838       Record.clear();
1839       continue;
1840     }
1841     const Constant *C = cast<Constant>(V);
1842     unsigned Code = -1U;
1843     unsigned AbbrevToUse = 0;
1844     if (C->isNullValue()) {
1845       Code = bitc::CST_CODE_NULL;
1846     } else if (isa<UndefValue>(C)) {
1847       Code = bitc::CST_CODE_UNDEF;
1848     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
1849       if (IV->getBitWidth() <= 64) {
1850         uint64_t V = IV->getSExtValue();
1851         emitSignedInt64(Record, V);
1852         Code = bitc::CST_CODE_INTEGER;
1853         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
1854       } else {                             // Wide integers, > 64 bits in size.
1855         // We have an arbitrary precision integer value to write whose
1856         // bit width is > 64. However, in canonical unsigned integer
1857         // format it is likely that the high bits are going to be zero.
1858         // So, we only write the number of active words.
1859         unsigned NWords = IV->getValue().getActiveWords();
1860         const uint64_t *RawWords = IV->getValue().getRawData();
1861         for (unsigned i = 0; i != NWords; ++i) {
1862           emitSignedInt64(Record, RawWords[i]);
1863         }
1864         Code = bitc::CST_CODE_WIDE_INTEGER;
1865       }
1866     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
1867       Code = bitc::CST_CODE_FLOAT;
1868       Type *Ty = CFP->getType();
1869       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
1870         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
1871       } else if (Ty->isX86_FP80Ty()) {
1872         // api needed to prevent premature destruction
1873         // bits are not in the same order as a normal i80 APInt, compensate.
1874         APInt api = CFP->getValueAPF().bitcastToAPInt();
1875         const uint64_t *p = api.getRawData();
1876         Record.push_back((p[1] << 48) | (p[0] >> 16));
1877         Record.push_back(p[0] & 0xffffLL);
1878       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
1879         APInt api = CFP->getValueAPF().bitcastToAPInt();
1880         const uint64_t *p = api.getRawData();
1881         Record.push_back(p[0]);
1882         Record.push_back(p[1]);
1883       } else {
1884         assert (0 && "Unknown FP type!");
1885       }
1886     } else if (isa<ConstantDataSequential>(C) &&
1887                cast<ConstantDataSequential>(C)->isString()) {
1888       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
1889       // Emit constant strings specially.
1890       unsigned NumElts = Str->getNumElements();
1891       // If this is a null-terminated string, use the denser CSTRING encoding.
1892       if (Str->isCString()) {
1893         Code = bitc::CST_CODE_CSTRING;
1894         --NumElts;  // Don't encode the null, which isn't allowed by char6.
1895       } else {
1896         Code = bitc::CST_CODE_STRING;
1897         AbbrevToUse = String8Abbrev;
1898       }
1899       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
1900       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
1901       for (unsigned i = 0; i != NumElts; ++i) {
1902         unsigned char V = Str->getElementAsInteger(i);
1903         Record.push_back(V);
1904         isCStr7 &= (V & 128) == 0;
1905         if (isCStrChar6)
1906           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
1907       }
1908 
1909       if (isCStrChar6)
1910         AbbrevToUse = CString6Abbrev;
1911       else if (isCStr7)
1912         AbbrevToUse = CString7Abbrev;
1913     } else if (const ConstantDataSequential *CDS =
1914                   dyn_cast<ConstantDataSequential>(C)) {
1915       Code = bitc::CST_CODE_DATA;
1916       Type *EltTy = CDS->getType()->getElementType();
1917       if (isa<IntegerType>(EltTy)) {
1918         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
1919           Record.push_back(CDS->getElementAsInteger(i));
1920       } else {
1921         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
1922           Record.push_back(
1923               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
1924       }
1925     } else if (isa<ConstantAggregate>(C)) {
1926       Code = bitc::CST_CODE_AGGREGATE;
1927       for (const Value *Op : C->operands())
1928         Record.push_back(VE.getValueID(Op));
1929       AbbrevToUse = AggregateAbbrev;
1930     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
1931       switch (CE->getOpcode()) {
1932       default:
1933         if (Instruction::isCast(CE->getOpcode())) {
1934           Code = bitc::CST_CODE_CE_CAST;
1935           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
1936           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1937           Record.push_back(VE.getValueID(C->getOperand(0)));
1938           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
1939         } else {
1940           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
1941           Code = bitc::CST_CODE_CE_BINOP;
1942           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
1943           Record.push_back(VE.getValueID(C->getOperand(0)));
1944           Record.push_back(VE.getValueID(C->getOperand(1)));
1945           uint64_t Flags = getOptimizationFlags(CE);
1946           if (Flags != 0)
1947             Record.push_back(Flags);
1948         }
1949         break;
1950       case Instruction::GetElementPtr: {
1951         Code = bitc::CST_CODE_CE_GEP;
1952         const auto *GO = cast<GEPOperator>(C);
1953         if (GO->isInBounds())
1954           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
1955         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
1956         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
1957           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
1958           Record.push_back(VE.getValueID(C->getOperand(i)));
1959         }
1960         break;
1961       }
1962       case Instruction::Select:
1963         Code = bitc::CST_CODE_CE_SELECT;
1964         Record.push_back(VE.getValueID(C->getOperand(0)));
1965         Record.push_back(VE.getValueID(C->getOperand(1)));
1966         Record.push_back(VE.getValueID(C->getOperand(2)));
1967         break;
1968       case Instruction::ExtractElement:
1969         Code = bitc::CST_CODE_CE_EXTRACTELT;
1970         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1971         Record.push_back(VE.getValueID(C->getOperand(0)));
1972         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
1973         Record.push_back(VE.getValueID(C->getOperand(1)));
1974         break;
1975       case Instruction::InsertElement:
1976         Code = bitc::CST_CODE_CE_INSERTELT;
1977         Record.push_back(VE.getValueID(C->getOperand(0)));
1978         Record.push_back(VE.getValueID(C->getOperand(1)));
1979         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
1980         Record.push_back(VE.getValueID(C->getOperand(2)));
1981         break;
1982       case Instruction::ShuffleVector:
1983         // If the return type and argument types are the same, this is a
1984         // standard shufflevector instruction.  If the types are different,
1985         // then the shuffle is widening or truncating the input vectors, and
1986         // the argument type must also be encoded.
1987         if (C->getType() == C->getOperand(0)->getType()) {
1988           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
1989         } else {
1990           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
1991           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1992         }
1993         Record.push_back(VE.getValueID(C->getOperand(0)));
1994         Record.push_back(VE.getValueID(C->getOperand(1)));
1995         Record.push_back(VE.getValueID(C->getOperand(2)));
1996         break;
1997       case Instruction::ICmp:
1998       case Instruction::FCmp:
1999         Code = bitc::CST_CODE_CE_CMP;
2000         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2001         Record.push_back(VE.getValueID(C->getOperand(0)));
2002         Record.push_back(VE.getValueID(C->getOperand(1)));
2003         Record.push_back(CE->getPredicate());
2004         break;
2005       }
2006     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2007       Code = bitc::CST_CODE_BLOCKADDRESS;
2008       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2009       Record.push_back(VE.getValueID(BA->getFunction()));
2010       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2011     } else {
2012 #ifndef NDEBUG
2013       C->dump();
2014 #endif
2015       llvm_unreachable("Unknown constant!");
2016     }
2017     stream().EmitRecord(Code, Record, AbbrevToUse);
2018     Record.clear();
2019   }
2020 
2021   stream().ExitBlock();
2022 }
2023 
2024 void ModuleBitcodeWriter::writeModuleConstants() {
2025   const ValueEnumerator::ValueList &Vals = VE.getValues();
2026 
2027   // Find the first constant to emit, which is the first non-globalvalue value.
2028   // We know globalvalues have been emitted by WriteModuleInfo.
2029   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2030     if (!isa<GlobalValue>(Vals[i].first)) {
2031       writeConstants(i, Vals.size(), true);
2032       return;
2033     }
2034   }
2035 }
2036 
2037 /// pushValueAndType - The file has to encode both the value and type id for
2038 /// many values, because we need to know what type to create for forward
2039 /// references.  However, most operands are not forward references, so this type
2040 /// field is not needed.
2041 ///
2042 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2043 /// instruction ID, then it is a forward reference, and it also includes the
2044 /// type ID.  The value ID that is written is encoded relative to the InstID.
2045 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2046                                            SmallVectorImpl<unsigned> &Vals) {
2047   unsigned ValID = VE.getValueID(V);
2048   // Make encoding relative to the InstID.
2049   Vals.push_back(InstID - ValID);
2050   if (ValID >= InstID) {
2051     Vals.push_back(VE.getTypeID(V->getType()));
2052     return true;
2053   }
2054   return false;
2055 }
2056 
2057 void ModuleBitcodeWriter::writeOperandBundles(ImmutableCallSite CS,
2058                                               unsigned InstID) {
2059   SmallVector<unsigned, 64> Record;
2060   LLVMContext &C = CS.getInstruction()->getContext();
2061 
2062   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2063     const auto &Bundle = CS.getOperandBundleAt(i);
2064     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2065 
2066     for (auto &Input : Bundle.Inputs)
2067       pushValueAndType(Input, InstID, Record);
2068 
2069     stream().EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2070     Record.clear();
2071   }
2072 }
2073 
2074 /// pushValue - Like pushValueAndType, but where the type of the value is
2075 /// omitted (perhaps it was already encoded in an earlier operand).
2076 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2077                                     SmallVectorImpl<unsigned> &Vals) {
2078   unsigned ValID = VE.getValueID(V);
2079   Vals.push_back(InstID - ValID);
2080 }
2081 
2082 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2083                                           SmallVectorImpl<uint64_t> &Vals) {
2084   unsigned ValID = VE.getValueID(V);
2085   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2086   emitSignedInt64(Vals, diff);
2087 }
2088 
2089 /// WriteInstruction - Emit an instruction to the specified stream.
2090 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2091                                            unsigned InstID,
2092                                            SmallVectorImpl<unsigned> &Vals) {
2093   unsigned Code = 0;
2094   unsigned AbbrevToUse = 0;
2095   VE.setInstructionID(&I);
2096   switch (I.getOpcode()) {
2097   default:
2098     if (Instruction::isCast(I.getOpcode())) {
2099       Code = bitc::FUNC_CODE_INST_CAST;
2100       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2101         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2102       Vals.push_back(VE.getTypeID(I.getType()));
2103       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2104     } else {
2105       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2106       Code = bitc::FUNC_CODE_INST_BINOP;
2107       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2108         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2109       pushValue(I.getOperand(1), InstID, Vals);
2110       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2111       uint64_t Flags = getOptimizationFlags(&I);
2112       if (Flags != 0) {
2113         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2114           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2115         Vals.push_back(Flags);
2116       }
2117     }
2118     break;
2119 
2120   case Instruction::GetElementPtr: {
2121     Code = bitc::FUNC_CODE_INST_GEP;
2122     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2123     auto &GEPInst = cast<GetElementPtrInst>(I);
2124     Vals.push_back(GEPInst.isInBounds());
2125     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2126     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2127       pushValueAndType(I.getOperand(i), InstID, Vals);
2128     break;
2129   }
2130   case Instruction::ExtractValue: {
2131     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2132     pushValueAndType(I.getOperand(0), InstID, Vals);
2133     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2134     Vals.append(EVI->idx_begin(), EVI->idx_end());
2135     break;
2136   }
2137   case Instruction::InsertValue: {
2138     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2139     pushValueAndType(I.getOperand(0), InstID, Vals);
2140     pushValueAndType(I.getOperand(1), InstID, Vals);
2141     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2142     Vals.append(IVI->idx_begin(), IVI->idx_end());
2143     break;
2144   }
2145   case Instruction::Select:
2146     Code = bitc::FUNC_CODE_INST_VSELECT;
2147     pushValueAndType(I.getOperand(1), InstID, Vals);
2148     pushValue(I.getOperand(2), InstID, Vals);
2149     pushValueAndType(I.getOperand(0), InstID, Vals);
2150     break;
2151   case Instruction::ExtractElement:
2152     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2153     pushValueAndType(I.getOperand(0), InstID, Vals);
2154     pushValueAndType(I.getOperand(1), InstID, Vals);
2155     break;
2156   case Instruction::InsertElement:
2157     Code = bitc::FUNC_CODE_INST_INSERTELT;
2158     pushValueAndType(I.getOperand(0), InstID, Vals);
2159     pushValue(I.getOperand(1), InstID, Vals);
2160     pushValueAndType(I.getOperand(2), InstID, Vals);
2161     break;
2162   case Instruction::ShuffleVector:
2163     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2164     pushValueAndType(I.getOperand(0), InstID, Vals);
2165     pushValue(I.getOperand(1), InstID, Vals);
2166     pushValue(I.getOperand(2), InstID, Vals);
2167     break;
2168   case Instruction::ICmp:
2169   case Instruction::FCmp: {
2170     // compare returning Int1Ty or vector of Int1Ty
2171     Code = bitc::FUNC_CODE_INST_CMP2;
2172     pushValueAndType(I.getOperand(0), InstID, Vals);
2173     pushValue(I.getOperand(1), InstID, Vals);
2174     Vals.push_back(cast<CmpInst>(I).getPredicate());
2175     uint64_t Flags = getOptimizationFlags(&I);
2176     if (Flags != 0)
2177       Vals.push_back(Flags);
2178     break;
2179   }
2180 
2181   case Instruction::Ret:
2182     {
2183       Code = bitc::FUNC_CODE_INST_RET;
2184       unsigned NumOperands = I.getNumOperands();
2185       if (NumOperands == 0)
2186         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2187       else if (NumOperands == 1) {
2188         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2189           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2190       } else {
2191         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2192           pushValueAndType(I.getOperand(i), InstID, Vals);
2193       }
2194     }
2195     break;
2196   case Instruction::Br:
2197     {
2198       Code = bitc::FUNC_CODE_INST_BR;
2199       const BranchInst &II = cast<BranchInst>(I);
2200       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2201       if (II.isConditional()) {
2202         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2203         pushValue(II.getCondition(), InstID, Vals);
2204       }
2205     }
2206     break;
2207   case Instruction::Switch:
2208     {
2209       Code = bitc::FUNC_CODE_INST_SWITCH;
2210       const SwitchInst &SI = cast<SwitchInst>(I);
2211       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2212       pushValue(SI.getCondition(), InstID, Vals);
2213       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2214       for (SwitchInst::ConstCaseIt Case : SI.cases()) {
2215         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2216         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2217       }
2218     }
2219     break;
2220   case Instruction::IndirectBr:
2221     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2222     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2223     // Encode the address operand as relative, but not the basic blocks.
2224     pushValue(I.getOperand(0), InstID, Vals);
2225     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2226       Vals.push_back(VE.getValueID(I.getOperand(i)));
2227     break;
2228 
2229   case Instruction::Invoke: {
2230     const InvokeInst *II = cast<InvokeInst>(&I);
2231     const Value *Callee = II->getCalledValue();
2232     FunctionType *FTy = II->getFunctionType();
2233 
2234     if (II->hasOperandBundles())
2235       writeOperandBundles(II, InstID);
2236 
2237     Code = bitc::FUNC_CODE_INST_INVOKE;
2238 
2239     Vals.push_back(VE.getAttributeID(II->getAttributes()));
2240     Vals.push_back(II->getCallingConv() | 1 << 13);
2241     Vals.push_back(VE.getValueID(II->getNormalDest()));
2242     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2243     Vals.push_back(VE.getTypeID(FTy));
2244     pushValueAndType(Callee, InstID, Vals);
2245 
2246     // Emit value #'s for the fixed parameters.
2247     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2248       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2249 
2250     // Emit type/value pairs for varargs params.
2251     if (FTy->isVarArg()) {
2252       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
2253            i != e; ++i)
2254         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2255     }
2256     break;
2257   }
2258   case Instruction::Resume:
2259     Code = bitc::FUNC_CODE_INST_RESUME;
2260     pushValueAndType(I.getOperand(0), InstID, Vals);
2261     break;
2262   case Instruction::CleanupRet: {
2263     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2264     const auto &CRI = cast<CleanupReturnInst>(I);
2265     pushValue(CRI.getCleanupPad(), InstID, Vals);
2266     if (CRI.hasUnwindDest())
2267       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2268     break;
2269   }
2270   case Instruction::CatchRet: {
2271     Code = bitc::FUNC_CODE_INST_CATCHRET;
2272     const auto &CRI = cast<CatchReturnInst>(I);
2273     pushValue(CRI.getCatchPad(), InstID, Vals);
2274     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2275     break;
2276   }
2277   case Instruction::CleanupPad:
2278   case Instruction::CatchPad: {
2279     const auto &FuncletPad = cast<FuncletPadInst>(I);
2280     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2281                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2282     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2283 
2284     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2285     Vals.push_back(NumArgOperands);
2286     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2287       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2288     break;
2289   }
2290   case Instruction::CatchSwitch: {
2291     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2292     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2293 
2294     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2295 
2296     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2297     Vals.push_back(NumHandlers);
2298     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2299       Vals.push_back(VE.getValueID(CatchPadBB));
2300 
2301     if (CatchSwitch.hasUnwindDest())
2302       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
2303     break;
2304   }
2305   case Instruction::Unreachable:
2306     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
2307     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
2308     break;
2309 
2310   case Instruction::PHI: {
2311     const PHINode &PN = cast<PHINode>(I);
2312     Code = bitc::FUNC_CODE_INST_PHI;
2313     // With the newer instruction encoding, forward references could give
2314     // negative valued IDs.  This is most common for PHIs, so we use
2315     // signed VBRs.
2316     SmallVector<uint64_t, 128> Vals64;
2317     Vals64.push_back(VE.getTypeID(PN.getType()));
2318     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
2319       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
2320       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
2321     }
2322     // Emit a Vals64 vector and exit.
2323     stream().EmitRecord(Code, Vals64, AbbrevToUse);
2324     Vals64.clear();
2325     return;
2326   }
2327 
2328   case Instruction::LandingPad: {
2329     const LandingPadInst &LP = cast<LandingPadInst>(I);
2330     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
2331     Vals.push_back(VE.getTypeID(LP.getType()));
2332     Vals.push_back(LP.isCleanup());
2333     Vals.push_back(LP.getNumClauses());
2334     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
2335       if (LP.isCatch(I))
2336         Vals.push_back(LandingPadInst::Catch);
2337       else
2338         Vals.push_back(LandingPadInst::Filter);
2339       pushValueAndType(LP.getClause(I), InstID, Vals);
2340     }
2341     break;
2342   }
2343 
2344   case Instruction::Alloca: {
2345     Code = bitc::FUNC_CODE_INST_ALLOCA;
2346     const AllocaInst &AI = cast<AllocaInst>(I);
2347     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
2348     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2349     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
2350     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
2351     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
2352            "not enough bits for maximum alignment");
2353     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
2354     AlignRecord |= AI.isUsedWithInAlloca() << 5;
2355     AlignRecord |= 1 << 6;
2356     AlignRecord |= AI.isSwiftError() << 7;
2357     Vals.push_back(AlignRecord);
2358     break;
2359   }
2360 
2361   case Instruction::Load:
2362     if (cast<LoadInst>(I).isAtomic()) {
2363       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
2364       pushValueAndType(I.getOperand(0), InstID, Vals);
2365     } else {
2366       Code = bitc::FUNC_CODE_INST_LOAD;
2367       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
2368         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
2369     }
2370     Vals.push_back(VE.getTypeID(I.getType()));
2371     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
2372     Vals.push_back(cast<LoadInst>(I).isVolatile());
2373     if (cast<LoadInst>(I).isAtomic()) {
2374       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
2375       Vals.push_back(getEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
2376     }
2377     break;
2378   case Instruction::Store:
2379     if (cast<StoreInst>(I).isAtomic())
2380       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
2381     else
2382       Code = bitc::FUNC_CODE_INST_STORE;
2383     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
2384     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
2385     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
2386     Vals.push_back(cast<StoreInst>(I).isVolatile());
2387     if (cast<StoreInst>(I).isAtomic()) {
2388       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
2389       Vals.push_back(getEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
2390     }
2391     break;
2392   case Instruction::AtomicCmpXchg:
2393     Code = bitc::FUNC_CODE_INST_CMPXCHG;
2394     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
2395     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
2396     pushValue(I.getOperand(2), InstID, Vals);        // newval.
2397     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
2398     Vals.push_back(
2399         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
2400     Vals.push_back(
2401         getEncodedSynchScope(cast<AtomicCmpXchgInst>(I).getSynchScope()));
2402     Vals.push_back(
2403         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
2404     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
2405     break;
2406   case Instruction::AtomicRMW:
2407     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
2408     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
2409     pushValue(I.getOperand(1), InstID, Vals);        // val.
2410     Vals.push_back(
2411         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
2412     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
2413     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
2414     Vals.push_back(
2415         getEncodedSynchScope(cast<AtomicRMWInst>(I).getSynchScope()));
2416     break;
2417   case Instruction::Fence:
2418     Code = bitc::FUNC_CODE_INST_FENCE;
2419     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
2420     Vals.push_back(getEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
2421     break;
2422   case Instruction::Call: {
2423     const CallInst &CI = cast<CallInst>(I);
2424     FunctionType *FTy = CI.getFunctionType();
2425 
2426     if (CI.hasOperandBundles())
2427       writeOperandBundles(&CI, InstID);
2428 
2429     Code = bitc::FUNC_CODE_INST_CALL;
2430 
2431     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
2432 
2433     unsigned Flags = getOptimizationFlags(&I);
2434     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
2435                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
2436                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
2437                    1 << bitc::CALL_EXPLICIT_TYPE |
2438                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
2439                    unsigned(Flags != 0) << bitc::CALL_FMF);
2440     if (Flags != 0)
2441       Vals.push_back(Flags);
2442 
2443     Vals.push_back(VE.getTypeID(FTy));
2444     pushValueAndType(CI.getCalledValue(), InstID, Vals); // Callee
2445 
2446     // Emit value #'s for the fixed parameters.
2447     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
2448       // Check for labels (can happen with asm labels).
2449       if (FTy->getParamType(i)->isLabelTy())
2450         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
2451       else
2452         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
2453     }
2454 
2455     // Emit type/value pairs for varargs params.
2456     if (FTy->isVarArg()) {
2457       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
2458            i != e; ++i)
2459         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
2460     }
2461     break;
2462   }
2463   case Instruction::VAArg:
2464     Code = bitc::FUNC_CODE_INST_VAARG;
2465     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
2466     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
2467     Vals.push_back(VE.getTypeID(I.getType())); // restype.
2468     break;
2469   }
2470 
2471   stream().EmitRecord(Code, Vals, AbbrevToUse);
2472   Vals.clear();
2473 }
2474 
2475 /// Emit names for globals/functions etc. \p IsModuleLevel is true when
2476 /// we are writing the module-level VST, where we are including a function
2477 /// bitcode index and need to backpatch the VST forward declaration record.
2478 void ModuleBitcodeWriter::writeValueSymbolTable(
2479     const ValueSymbolTable &VST, bool IsModuleLevel,
2480     DenseMap<const Function *, uint64_t> *FunctionToBitcodeIndex) {
2481   if (VST.empty()) {
2482     // writeValueSymbolTableForwardDecl should have returned early as
2483     // well. Ensure this handling remains in sync by asserting that
2484     // the placeholder offset is not set.
2485     assert(!IsModuleLevel || !hasVSTOffsetPlaceholder());
2486     return;
2487   }
2488 
2489   if (IsModuleLevel && hasVSTOffsetPlaceholder()) {
2490     // Get the offset of the VST we are writing, and backpatch it into
2491     // the VST forward declaration record.
2492     uint64_t VSTOffset = stream().GetCurrentBitNo();
2493     // The BitcodeStartBit was the stream offset of the actual bitcode
2494     // (e.g. excluding any initial darwin header).
2495     VSTOffset -= bitcodeStartBit();
2496     assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
2497     stream().BackpatchWord(getVSTOffsetPlaceholder(), VSTOffset / 32);
2498   }
2499 
2500   stream().EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
2501 
2502   // For the module-level VST, add abbrev Ids for the VST_CODE_FNENTRY
2503   // records, which are not used in the per-function VSTs.
2504   unsigned FnEntry8BitAbbrev;
2505   unsigned FnEntry7BitAbbrev;
2506   unsigned FnEntry6BitAbbrev;
2507   if (IsModuleLevel && hasVSTOffsetPlaceholder()) {
2508     // 8-bit fixed-width VST_CODE_FNENTRY function strings.
2509     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2510     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2511     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2512     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2513     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2514     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2515     FnEntry8BitAbbrev = stream().EmitAbbrev(Abbv);
2516 
2517     // 7-bit fixed width VST_CODE_FNENTRY function strings.
2518     Abbv = new BitCodeAbbrev();
2519     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2520     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2521     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2522     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2523     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2524     FnEntry7BitAbbrev = stream().EmitAbbrev(Abbv);
2525 
2526     // 6-bit char6 VST_CODE_FNENTRY function strings.
2527     Abbv = new BitCodeAbbrev();
2528     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2529     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2530     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2531     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2532     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2533     FnEntry6BitAbbrev = stream().EmitAbbrev(Abbv);
2534   }
2535 
2536   // FIXME: Set up the abbrev, we know how many values there are!
2537   // FIXME: We know if the type names can use 7-bit ascii.
2538   SmallVector<unsigned, 64> NameVals;
2539 
2540   for (const ValueName &Name : VST) {
2541     // Figure out the encoding to use for the name.
2542     StringEncoding Bits =
2543         getStringEncoding(Name.getKeyData(), Name.getKeyLength());
2544 
2545     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
2546     NameVals.push_back(VE.getValueID(Name.getValue()));
2547 
2548     Function *F = dyn_cast<Function>(Name.getValue());
2549     if (!F) {
2550       // If value is an alias, need to get the aliased base object to
2551       // see if it is a function.
2552       auto *GA = dyn_cast<GlobalAlias>(Name.getValue());
2553       if (GA && GA->getBaseObject())
2554         F = dyn_cast<Function>(GA->getBaseObject());
2555     }
2556 
2557     // VST_CODE_ENTRY:   [valueid, namechar x N]
2558     // VST_CODE_FNENTRY: [valueid, funcoffset, namechar x N]
2559     // VST_CODE_BBENTRY: [bbid, namechar x N]
2560     unsigned Code;
2561     if (isa<BasicBlock>(Name.getValue())) {
2562       Code = bitc::VST_CODE_BBENTRY;
2563       if (Bits == SE_Char6)
2564         AbbrevToUse = VST_BBENTRY_6_ABBREV;
2565     } else if (F && !F->isDeclaration()) {
2566       // Must be the module-level VST, where we pass in the Index and
2567       // have a VSTOffsetPlaceholder. The function-level VST should not
2568       // contain any Function symbols.
2569       assert(FunctionToBitcodeIndex);
2570       assert(hasVSTOffsetPlaceholder());
2571 
2572       // Save the word offset of the function (from the start of the
2573       // actual bitcode written to the stream).
2574       uint64_t BitcodeIndex = (*FunctionToBitcodeIndex)[F] - bitcodeStartBit();
2575       assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
2576       NameVals.push_back(BitcodeIndex / 32);
2577 
2578       Code = bitc::VST_CODE_FNENTRY;
2579       AbbrevToUse = FnEntry8BitAbbrev;
2580       if (Bits == SE_Char6)
2581         AbbrevToUse = FnEntry6BitAbbrev;
2582       else if (Bits == SE_Fixed7)
2583         AbbrevToUse = FnEntry7BitAbbrev;
2584     } else {
2585       Code = bitc::VST_CODE_ENTRY;
2586       if (Bits == SE_Char6)
2587         AbbrevToUse = VST_ENTRY_6_ABBREV;
2588       else if (Bits == SE_Fixed7)
2589         AbbrevToUse = VST_ENTRY_7_ABBREV;
2590     }
2591 
2592     for (const auto P : Name.getKey())
2593       NameVals.push_back((unsigned char)P);
2594 
2595     // Emit the finished record.
2596     stream().EmitRecord(Code, NameVals, AbbrevToUse);
2597     NameVals.clear();
2598   }
2599   stream().ExitBlock();
2600 }
2601 
2602 /// Emit function names and summary offsets for the combined index
2603 /// used by ThinLTO.
2604 void IndexBitcodeWriter::writeCombinedValueSymbolTable() {
2605   assert(hasVSTOffsetPlaceholder() && "Expected non-zero VSTOffsetPlaceholder");
2606   // Get the offset of the VST we are writing, and backpatch it into
2607   // the VST forward declaration record.
2608   uint64_t VSTOffset = stream().GetCurrentBitNo();
2609   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
2610   stream().BackpatchWord(getVSTOffsetPlaceholder(), VSTOffset / 32);
2611 
2612   stream().EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
2613 
2614   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2615   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_COMBINED_GVDEFENTRY));
2616   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
2617   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // sumoffset
2618   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // guid
2619   unsigned DefEntryAbbrev = stream().EmitAbbrev(Abbv);
2620 
2621   Abbv = new BitCodeAbbrev();
2622   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_COMBINED_ENTRY));
2623   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
2624   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // refguid
2625   unsigned EntryAbbrev = stream().EmitAbbrev(Abbv);
2626 
2627   SmallVector<uint64_t, 64> NameVals;
2628 
2629   for (const auto &FII : *Index) {
2630     GlobalValue::GUID FuncGUID = FII.first;
2631     unsigned ValueId = popValueId(FuncGUID);
2632 
2633     for (const auto &FI : FII.second) {
2634       // VST_CODE_COMBINED_GVDEFENTRY: [valueid, sumoffset, guid]
2635       NameVals.push_back(ValueId);
2636       NameVals.push_back(FI->bitcodeIndex());
2637       NameVals.push_back(FuncGUID);
2638 
2639       // Emit the finished record.
2640       stream().EmitRecord(bitc::VST_CODE_COMBINED_GVDEFENTRY, NameVals,
2641                           DefEntryAbbrev);
2642       NameVals.clear();
2643     }
2644   }
2645   for (const auto &GVI : valueIds()) {
2646     // VST_CODE_COMBINED_ENTRY: [valueid, refguid]
2647     NameVals.push_back(GVI.second);
2648     NameVals.push_back(GVI.first);
2649 
2650     // Emit the finished record.
2651     stream().EmitRecord(bitc::VST_CODE_COMBINED_ENTRY, NameVals, EntryAbbrev);
2652     NameVals.clear();
2653   }
2654   stream().ExitBlock();
2655 }
2656 
2657 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
2658   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
2659   unsigned Code;
2660   if (isa<BasicBlock>(Order.V))
2661     Code = bitc::USELIST_CODE_BB;
2662   else
2663     Code = bitc::USELIST_CODE_DEFAULT;
2664 
2665   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
2666   Record.push_back(VE.getValueID(Order.V));
2667   stream().EmitRecord(Code, Record);
2668 }
2669 
2670 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
2671   assert(VE.shouldPreserveUseListOrder() &&
2672          "Expected to be preserving use-list order");
2673 
2674   auto hasMore = [&]() {
2675     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
2676   };
2677   if (!hasMore())
2678     // Nothing to do.
2679     return;
2680 
2681   stream().EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
2682   while (hasMore()) {
2683     writeUseList(std::move(VE.UseListOrders.back()));
2684     VE.UseListOrders.pop_back();
2685   }
2686   stream().ExitBlock();
2687 }
2688 
2689 /// Emit a function body to the module stream.
2690 void ModuleBitcodeWriter::writeFunction(
2691     const Function &F,
2692     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
2693   // Save the bitcode index of the start of this function block for recording
2694   // in the VST.
2695   FunctionToBitcodeIndex[&F] = stream().GetCurrentBitNo();
2696 
2697   stream().EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
2698   VE.incorporateFunction(F);
2699 
2700   SmallVector<unsigned, 64> Vals;
2701 
2702   // Emit the number of basic blocks, so the reader can create them ahead of
2703   // time.
2704   Vals.push_back(VE.getBasicBlocks().size());
2705   stream().EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
2706   Vals.clear();
2707 
2708   // If there are function-local constants, emit them now.
2709   unsigned CstStart, CstEnd;
2710   VE.getFunctionConstantRange(CstStart, CstEnd);
2711   writeConstants(CstStart, CstEnd, false);
2712 
2713   // If there is function-local metadata, emit it now.
2714   writeFunctionMetadata(F);
2715 
2716   // Keep a running idea of what the instruction ID is.
2717   unsigned InstID = CstEnd;
2718 
2719   bool NeedsMetadataAttachment = F.hasMetadata();
2720 
2721   DILocation *LastDL = nullptr;
2722   // Finally, emit all the instructions, in order.
2723   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
2724     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
2725          I != E; ++I) {
2726       writeInstruction(*I, InstID, Vals);
2727 
2728       if (!I->getType()->isVoidTy())
2729         ++InstID;
2730 
2731       // If the instruction has metadata, write a metadata attachment later.
2732       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
2733 
2734       // If the instruction has a debug location, emit it.
2735       DILocation *DL = I->getDebugLoc();
2736       if (!DL)
2737         continue;
2738 
2739       if (DL == LastDL) {
2740         // Just repeat the same debug loc as last time.
2741         stream().EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
2742         continue;
2743       }
2744 
2745       Vals.push_back(DL->getLine());
2746       Vals.push_back(DL->getColumn());
2747       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
2748       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
2749       stream().EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
2750       Vals.clear();
2751 
2752       LastDL = DL;
2753     }
2754 
2755   // Emit names for all the instructions etc.
2756   writeValueSymbolTable(F.getValueSymbolTable());
2757 
2758   if (NeedsMetadataAttachment)
2759     writeMetadataAttachment(F);
2760   if (VE.shouldPreserveUseListOrder())
2761     writeUseListBlock(&F);
2762   VE.purgeFunction();
2763   stream().ExitBlock();
2764 }
2765 
2766 // Emit blockinfo, which defines the standard abbreviations etc.
2767 void ModuleBitcodeWriter::writeBlockInfo() {
2768   // We only want to emit block info records for blocks that have multiple
2769   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
2770   // Other blocks can define their abbrevs inline.
2771   stream().EnterBlockInfoBlock(2);
2772 
2773   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
2774     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2775     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
2776     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2777     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2778     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2779     if (stream().EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
2780         VST_ENTRY_8_ABBREV)
2781       llvm_unreachable("Unexpected abbrev ordering!");
2782   }
2783 
2784   { // 7-bit fixed width VST_CODE_ENTRY strings.
2785     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2786     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2787     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2788     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2789     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2790     if (stream().EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
2791         VST_ENTRY_7_ABBREV)
2792       llvm_unreachable("Unexpected abbrev ordering!");
2793   }
2794   { // 6-bit char6 VST_CODE_ENTRY strings.
2795     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2796     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2797     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2798     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2799     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2800     if (stream().EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
2801         VST_ENTRY_6_ABBREV)
2802       llvm_unreachable("Unexpected abbrev ordering!");
2803   }
2804   { // 6-bit char6 VST_CODE_BBENTRY strings.
2805     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2806     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
2807     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2808     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2809     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2810     if (stream().EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
2811         VST_BBENTRY_6_ABBREV)
2812       llvm_unreachable("Unexpected abbrev ordering!");
2813   }
2814 
2815 
2816 
2817   { // SETTYPE abbrev for CONSTANTS_BLOCK.
2818     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2819     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
2820     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
2821                               VE.computeBitsRequiredForTypeIndicies()));
2822     if (stream().EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
2823         CONSTANTS_SETTYPE_ABBREV)
2824       llvm_unreachable("Unexpected abbrev ordering!");
2825   }
2826 
2827   { // INTEGER abbrev for CONSTANTS_BLOCK.
2828     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2829     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
2830     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2831     if (stream().EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
2832         CONSTANTS_INTEGER_ABBREV)
2833       llvm_unreachable("Unexpected abbrev ordering!");
2834   }
2835 
2836   { // CE_CAST abbrev for CONSTANTS_BLOCK.
2837     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2838     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
2839     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
2840     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
2841                               VE.computeBitsRequiredForTypeIndicies()));
2842     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
2843 
2844     if (stream().EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
2845         CONSTANTS_CE_CAST_Abbrev)
2846       llvm_unreachable("Unexpected abbrev ordering!");
2847   }
2848   { // NULL abbrev for CONSTANTS_BLOCK.
2849     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2850     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
2851     if (stream().EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
2852         CONSTANTS_NULL_Abbrev)
2853       llvm_unreachable("Unexpected abbrev ordering!");
2854   }
2855 
2856   // FIXME: This should only use space for first class types!
2857 
2858   { // INST_LOAD abbrev for FUNCTION_BLOCK.
2859     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2860     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
2861     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
2862     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
2863                               VE.computeBitsRequiredForTypeIndicies()));
2864     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
2865     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
2866     if (stream().EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2867         FUNCTION_INST_LOAD_ABBREV)
2868       llvm_unreachable("Unexpected abbrev ordering!");
2869   }
2870   { // INST_BINOP abbrev for FUNCTION_BLOCK.
2871     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2872     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2873     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2874     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2875     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2876     if (stream().EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2877         FUNCTION_INST_BINOP_ABBREV)
2878       llvm_unreachable("Unexpected abbrev ordering!");
2879   }
2880   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
2881     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2882     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2883     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2884     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2885     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2886     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
2887     if (stream().EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2888         FUNCTION_INST_BINOP_FLAGS_ABBREV)
2889       llvm_unreachable("Unexpected abbrev ordering!");
2890   }
2891   { // INST_CAST abbrev for FUNCTION_BLOCK.
2892     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2893     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
2894     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
2895     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
2896                               VE.computeBitsRequiredForTypeIndicies()));
2897     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
2898     if (stream().EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2899         FUNCTION_INST_CAST_ABBREV)
2900       llvm_unreachable("Unexpected abbrev ordering!");
2901   }
2902 
2903   { // INST_RET abbrev for FUNCTION_BLOCK.
2904     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2905     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2906     if (stream().EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2907         FUNCTION_INST_RET_VOID_ABBREV)
2908       llvm_unreachable("Unexpected abbrev ordering!");
2909   }
2910   { // INST_RET abbrev for FUNCTION_BLOCK.
2911     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2912     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2913     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
2914     if (stream().EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2915         FUNCTION_INST_RET_VAL_ABBREV)
2916       llvm_unreachable("Unexpected abbrev ordering!");
2917   }
2918   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
2919     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2920     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
2921     if (stream().EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2922         FUNCTION_INST_UNREACHABLE_ABBREV)
2923       llvm_unreachable("Unexpected abbrev ordering!");
2924   }
2925   {
2926     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2927     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
2928     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2929     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
2930                               Log2_32_Ceil(VE.getTypes().size() + 1)));
2931     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2932     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2933     if (stream().EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2934         FUNCTION_INST_GEP_ABBREV)
2935       llvm_unreachable("Unexpected abbrev ordering!");
2936   }
2937 
2938   stream().ExitBlock();
2939 }
2940 
2941 /// Write the module path strings, currently only used when generating
2942 /// a combined index file.
2943 void IndexBitcodeWriter::writeModStrings() {
2944   stream().EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
2945 
2946   // TODO: See which abbrev sizes we actually need to emit
2947 
2948   // 8-bit fixed-width MST_ENTRY strings.
2949   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2950   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
2951   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2952   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2953   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2954   unsigned Abbrev8Bit = stream().EmitAbbrev(Abbv);
2955 
2956   // 7-bit fixed width MST_ENTRY strings.
2957   Abbv = new BitCodeAbbrev();
2958   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
2959   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2960   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2961   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2962   unsigned Abbrev7Bit = stream().EmitAbbrev(Abbv);
2963 
2964   // 6-bit char6 MST_ENTRY strings.
2965   Abbv = new BitCodeAbbrev();
2966   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
2967   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2968   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2969   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2970   unsigned Abbrev6Bit = stream().EmitAbbrev(Abbv);
2971 
2972   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
2973   Abbv = new BitCodeAbbrev();
2974   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
2975   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2976   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2977   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2978   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2979   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2980   unsigned AbbrevHash = stream().EmitAbbrev(Abbv);
2981 
2982   SmallVector<unsigned, 64> Vals;
2983   for (const auto &MPSE : Index->modulePaths()) {
2984     StringEncoding Bits =
2985         getStringEncoding(MPSE.getKey().data(), MPSE.getKey().size());
2986     unsigned AbbrevToUse = Abbrev8Bit;
2987     if (Bits == SE_Char6)
2988       AbbrevToUse = Abbrev6Bit;
2989     else if (Bits == SE_Fixed7)
2990       AbbrevToUse = Abbrev7Bit;
2991 
2992     Vals.push_back(MPSE.getValue().first);
2993 
2994     for (const auto P : MPSE.getKey())
2995       Vals.push_back((unsigned char)P);
2996 
2997     // Emit the finished record.
2998     stream().EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
2999 
3000     Vals.clear();
3001     // Emit an optional hash for the module now
3002     auto &Hash = MPSE.getValue().second;
3003     bool AllZero = true; // Detect if the hash is empty, and do not generate it
3004     for (auto Val : Hash) {
3005       if (Val)
3006         AllZero = false;
3007       Vals.push_back(Val);
3008     }
3009     if (!AllZero) {
3010       // Emit the hash record.
3011       stream().EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3012     }
3013 
3014     Vals.clear();
3015   }
3016   stream().ExitBlock();
3017 }
3018 
3019 // Helper to emit a single function summary record.
3020 void ModuleBitcodeWriter::writePerModuleFunctionSummaryRecord(
3021     SmallVector<uint64_t, 64> &NameVals, GlobalValueInfo *Info,
3022     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3023     const Function &F) {
3024   NameVals.push_back(ValueID);
3025 
3026   FunctionSummary *FS = cast<FunctionSummary>(Info->summary());
3027   NameVals.push_back(getEncodedLinkage(FS->linkage()));
3028   NameVals.push_back(FS->instCount());
3029   NameVals.push_back(FS->refs().size());
3030 
3031   for (auto &RI : FS->refs())
3032     NameVals.push_back(VE.getValueID(RI.getValue()));
3033 
3034   bool HasProfileData = F.getEntryCount().hasValue();
3035   for (auto &ECI : FS->calls()) {
3036     NameVals.push_back(VE.getValueID(ECI.first.getValue()));
3037     assert(ECI.second.CallsiteCount > 0 && "Expected at least one callsite");
3038     NameVals.push_back(ECI.second.CallsiteCount);
3039     if (HasProfileData)
3040       NameVals.push_back(ECI.second.ProfileCount);
3041   }
3042 
3043   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3044   unsigned Code =
3045       (HasProfileData ? bitc::FS_PERMODULE_PROFILE : bitc::FS_PERMODULE);
3046 
3047   // Emit the finished record.
3048   stream().EmitRecord(Code, NameVals, FSAbbrev);
3049   NameVals.clear();
3050 }
3051 
3052 // Collect the global value references in the given variable's initializer,
3053 // and emit them in a summary record.
3054 void ModuleBitcodeWriter::writeModuleLevelReferences(
3055     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3056     unsigned FSModRefsAbbrev) {
3057   // Only interested in recording variable defs in the summary.
3058   if (V.isDeclaration())
3059     return;
3060   NameVals.push_back(VE.getValueID(&V));
3061   NameVals.push_back(getEncodedLinkage(V.getLinkage()));
3062   auto *Info = Index->getGlobalValueInfo(V);
3063   GlobalVarSummary *VS = cast<GlobalVarSummary>(Info->summary());
3064   for (auto Ref : VS->refs())
3065     NameVals.push_back(VE.getValueID(Ref.getValue()));
3066   stream().EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3067                       FSModRefsAbbrev);
3068   NameVals.clear();
3069 }
3070 
3071 /// Emit the per-module summary section alongside the rest of
3072 /// the module's bitcode.
3073 void ModuleBitcodeWriter::writePerModuleGlobalValueSummary() {
3074   if (M->empty())
3075     return;
3076 
3077   if (Index->begin() == Index->end())
3078     return;
3079 
3080   stream().EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
3081 
3082   // Abbrev for FS_PERMODULE.
3083   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3084   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
3085   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3086   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // linkage
3087   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3088   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3089   // numrefs x valueid, n x (valueid, callsitecount)
3090   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3091   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3092   unsigned FSCallsAbbrev = stream().EmitAbbrev(Abbv);
3093 
3094   // Abbrev for FS_PERMODULE_PROFILE.
3095   Abbv = new BitCodeAbbrev();
3096   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
3097   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3098   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // linkage
3099   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3100   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3101   // numrefs x valueid, n x (valueid, callsitecount, profilecount)
3102   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3103   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3104   unsigned FSCallsProfileAbbrev = stream().EmitAbbrev(Abbv);
3105 
3106   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
3107   Abbv = new BitCodeAbbrev();
3108   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
3109   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3110   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // linkage
3111   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
3112   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3113   unsigned FSModRefsAbbrev = stream().EmitAbbrev(Abbv);
3114 
3115   // Abbrev for FS_ALIAS.
3116   Abbv = new BitCodeAbbrev();
3117   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
3118   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3119   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // linkage
3120   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3121   unsigned FSAliasAbbrev = stream().EmitAbbrev(Abbv);
3122 
3123   SmallVector<uint64_t, 64> NameVals;
3124   // Iterate over the list of functions instead of the Index to
3125   // ensure the ordering is stable.
3126   for (const Function &F : *M) {
3127     if (F.isDeclaration())
3128       continue;
3129     // Summary emission does not support anonymous functions, they have to
3130     // renamed using the anonymous function renaming pass.
3131     if (!F.hasName())
3132       report_fatal_error("Unexpected anonymous function when writing summary");
3133 
3134     auto *Info = Index->getGlobalValueInfo(F);
3135     writePerModuleFunctionSummaryRecord(
3136         NameVals, Info,
3137         VE.getValueID(M->getValueSymbolTable().lookup(F.getName())),
3138         FSCallsAbbrev, FSCallsProfileAbbrev, F);
3139   }
3140 
3141   // Capture references from GlobalVariable initializers, which are outside
3142   // of a function scope.
3143   for (const GlobalVariable &G : M->globals())
3144     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev);
3145 
3146   for (const GlobalAlias &A : M->aliases()) {
3147     auto *Aliasee = A.getBaseObject();
3148     if (!Aliasee->hasName())
3149       // Nameless function don't have an entry in the summary, skip it.
3150       continue;
3151     auto AliasId = VE.getValueID(&A);
3152     auto AliaseeId = VE.getValueID(Aliasee);
3153     NameVals.push_back(AliasId);
3154     NameVals.push_back(getEncodedLinkage(A.getLinkage()));
3155     NameVals.push_back(AliaseeId);
3156     stream().EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
3157     NameVals.clear();
3158   }
3159 
3160   stream().ExitBlock();
3161 }
3162 
3163 /// Emit the combined summary section into the combined index file.
3164 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
3165   stream().EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
3166 
3167   // Abbrev for FS_COMBINED.
3168   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3169   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
3170   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3171   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // linkage
3172   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3173   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3174   // numrefs x valueid, n x (valueid, callsitecount)
3175   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3176   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3177   unsigned FSCallsAbbrev = stream().EmitAbbrev(Abbv);
3178 
3179   // Abbrev for FS_COMBINED_PROFILE.
3180   Abbv = new BitCodeAbbrev();
3181   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
3182   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3183   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // linkage
3184   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3185   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3186   // numrefs x valueid, n x (valueid, callsitecount, profilecount)
3187   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3188   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3189   unsigned FSCallsProfileAbbrev = stream().EmitAbbrev(Abbv);
3190 
3191   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
3192   Abbv = new BitCodeAbbrev();
3193   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
3194   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3195   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // linkage
3196   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
3197   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3198   unsigned FSModRefsAbbrev = stream().EmitAbbrev(Abbv);
3199 
3200   // Abbrev for FS_COMBINED_ALIAS.
3201   Abbv = new BitCodeAbbrev();
3202   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
3203   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3204   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // linkage
3205   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // offset
3206   unsigned FSAliasAbbrev = stream().EmitAbbrev(Abbv);
3207 
3208   // The aliases are emitted as a post-pass, and will point to the summary
3209   // offset id of the aliasee. For this purpose we need to be able to get back
3210   // from the summary to the offset
3211   SmallVector<GlobalValueInfo *, 64> Aliases;
3212   DenseMap<const GlobalValueSummary *, uint64_t> SummaryToOffsetMap;
3213 
3214   SmallVector<uint64_t, 64> NameVals;
3215   for (const auto &FII : *Index) {
3216     for (auto &FI : FII.second) {
3217       GlobalValueSummary *S = FI->summary();
3218       assert(S);
3219       if (isa<AliasSummary>(S)) {
3220         // Will process aliases as a post-pass because the reader wants all
3221         // global to be loaded first.
3222         Aliases.push_back(FI.get());
3223         continue;
3224       }
3225 
3226       if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
3227         NameVals.push_back(Index->getModuleId(VS->modulePath()));
3228         NameVals.push_back(getEncodedLinkage(VS->linkage()));
3229         for (auto &RI : VS->refs()) {
3230           NameVals.push_back(getValueId(RI.getGUID()));
3231         }
3232 
3233         // Record the starting offset of this summary entry for use
3234         // in the VST entry. Add the current code size since the
3235         // reader will invoke readRecord after the abbrev id read.
3236         FI->setBitcodeIndex(stream().GetCurrentBitNo() +
3237                             stream().GetAbbrevIDWidth());
3238         // Store temporarily the offset in the map for a possible alias.
3239         SummaryToOffsetMap[S] = FI->bitcodeIndex();
3240 
3241         // Emit the finished record.
3242         stream().EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
3243                             FSModRefsAbbrev);
3244         NameVals.clear();
3245         continue;
3246       }
3247 
3248       auto *FS = cast<FunctionSummary>(S);
3249       NameVals.push_back(Index->getModuleId(FS->modulePath()));
3250       NameVals.push_back(getEncodedLinkage(FS->linkage()));
3251       NameVals.push_back(FS->instCount());
3252       NameVals.push_back(FS->refs().size());
3253 
3254       for (auto &RI : FS->refs()) {
3255         NameVals.push_back(getValueId(RI.getGUID()));
3256       }
3257 
3258       bool HasProfileData = false;
3259       for (auto &EI : FS->calls()) {
3260         HasProfileData |= EI.second.ProfileCount != 0;
3261         if (HasProfileData)
3262           break;
3263       }
3264 
3265       for (auto &EI : FS->calls()) {
3266         // If this GUID doesn't have a value id, it doesn't have a function
3267         // summary and we don't need to record any calls to it.
3268         if (!hasValueId(EI.first.getGUID()))
3269           continue;
3270         NameVals.push_back(getValueId(EI.first.getGUID()));
3271         assert(EI.second.CallsiteCount > 0 && "Expected at least one callsite");
3272         NameVals.push_back(EI.second.CallsiteCount);
3273         if (HasProfileData)
3274           NameVals.push_back(EI.second.ProfileCount);
3275       }
3276 
3277       // Record the starting offset of this summary entry for use
3278       // in the VST entry. Add the current code size since the
3279       // reader will invoke readRecord after the abbrev id read.
3280       FI->setBitcodeIndex(stream().GetCurrentBitNo() +
3281                           stream().GetAbbrevIDWidth());
3282       // Store temporarily the offset in the map for a possible alias.
3283       SummaryToOffsetMap[S] = FI->bitcodeIndex();
3284 
3285       unsigned FSAbbrev =
3286           (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3287       unsigned Code =
3288           (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
3289 
3290       // Emit the finished record.
3291       stream().EmitRecord(Code, NameVals, FSAbbrev);
3292       NameVals.clear();
3293     }
3294   }
3295 
3296   for (auto GVI : Aliases) {
3297     AliasSummary *AS = cast<AliasSummary>(GVI->summary());
3298     NameVals.push_back(Index->getModuleId(AS->modulePath()));
3299     NameVals.push_back(getEncodedLinkage(AS->linkage()));
3300     auto AliaseeOffset = SummaryToOffsetMap[&AS->getAliasee()];
3301     assert(AliaseeOffset);
3302     NameVals.push_back(AliaseeOffset);
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     GVI->setBitcodeIndex(stream().GetCurrentBitNo() +
3308                          stream().GetAbbrevIDWidth());
3309 
3310     // Emit the finished record.
3311     stream().EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
3312     NameVals.clear();
3313   }
3314 
3315   stream().ExitBlock();
3316 }
3317 
3318 void ModuleBitcodeWriter::writeIdentificationBlock() {
3319   stream().EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
3320 
3321   // Write the "user readable" string identifying the bitcode producer
3322   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3323   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
3324   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3325   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3326   auto StringAbbrev = stream().EmitAbbrev(Abbv);
3327   writeStringRecord(bitc::IDENTIFICATION_CODE_STRING,
3328                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
3329 
3330   // Write the epoch version
3331   Abbv = new BitCodeAbbrev();
3332   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
3333   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3334   auto EpochAbbrev = stream().EmitAbbrev(Abbv);
3335   SmallVector<unsigned, 1> Vals = {bitc::BITCODE_CURRENT_EPOCH};
3336   stream().EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
3337   stream().ExitBlock();
3338 }
3339 
3340 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
3341   // Emit the module's hash.
3342   // MODULE_CODE_HASH: [5*i32]
3343   SHA1 Hasher;
3344   Hasher.update(ArrayRef<uint8_t>((uint8_t *)&(buffer())[BlockStartPos],
3345                                   buffer().size() - BlockStartPos));
3346   auto Hash = Hasher.result();
3347   SmallVector<uint64_t, 20> Vals;
3348   auto LShift = [&](unsigned char Val, unsigned Amount)
3349                     -> uint64_t { return ((uint64_t)Val) << Amount; };
3350   for (int Pos = 0; Pos < 20; Pos += 4) {
3351     uint32_t SubHash = LShift(Hash[Pos + 0], 24);
3352     SubHash |= LShift(Hash[Pos + 1], 16) | LShift(Hash[Pos + 2], 8) |
3353                (unsigned)(unsigned char)Hash[Pos + 3];
3354     Vals.push_back(SubHash);
3355   }
3356 
3357   // Emit the finished record.
3358   stream().EmitRecord(bitc::MODULE_CODE_HASH, Vals);
3359 }
3360 
3361 void BitcodeWriter::write() {
3362   // Emit the file header first.
3363   writeBitcodeHeader();
3364 
3365   writeBlocks();
3366 }
3367 
3368 void ModuleBitcodeWriter::writeBlocks() {
3369   writeIdentificationBlock();
3370   writeModule();
3371 }
3372 
3373 void IndexBitcodeWriter::writeBlocks() {
3374   // Index contains only a single outer (module) block.
3375   writeIndex();
3376 }
3377 
3378 void ModuleBitcodeWriter::writeModule() {
3379   stream().EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
3380   size_t BlockStartPos = buffer().size();
3381 
3382   SmallVector<unsigned, 1> Vals;
3383   unsigned CurVersion = 1;
3384   Vals.push_back(CurVersion);
3385   stream().EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
3386 
3387   // Emit blockinfo, which defines the standard abbreviations etc.
3388   writeBlockInfo();
3389 
3390   // Emit information about attribute groups.
3391   writeAttributeGroupTable();
3392 
3393   // Emit information about parameter attributes.
3394   writeAttributeTable();
3395 
3396   // Emit information describing all of the types in the module.
3397   writeTypeTable();
3398 
3399   writeComdats();
3400 
3401   // Emit top-level description of module, including target triple, inline asm,
3402   // descriptors for global variables, and function prototype info.
3403   writeModuleInfo();
3404 
3405   // Emit constants.
3406   writeModuleConstants();
3407 
3408   // Emit metadata.
3409   writeModuleMetadata();
3410 
3411   // Emit metadata.
3412   writeModuleMetadataStore();
3413 
3414   // Emit module-level use-lists.
3415   if (VE.shouldPreserveUseListOrder())
3416     writeUseListBlock(nullptr);
3417 
3418   writeOperandBundleTags();
3419 
3420   // Emit function bodies.
3421   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
3422   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
3423     if (!F->isDeclaration())
3424       writeFunction(*F, FunctionToBitcodeIndex);
3425 
3426   // Need to write after the above call to WriteFunction which populates
3427   // the summary information in the index.
3428   if (Index)
3429     writePerModuleGlobalValueSummary();
3430 
3431   writeValueSymbolTable(M->getValueSymbolTable(),
3432                         /* IsModuleLevel */ true, &FunctionToBitcodeIndex);
3433 
3434   if (GenerateHash) {
3435     writeModuleHash(BlockStartPos);
3436   }
3437 
3438   stream().ExitBlock();
3439 }
3440 
3441 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
3442                                uint32_t &Position) {
3443   support::endian::write32le(&Buffer[Position], Value);
3444   Position += 4;
3445 }
3446 
3447 /// If generating a bc file on darwin, we have to emit a
3448 /// header and trailer to make it compatible with the system archiver.  To do
3449 /// this we emit the following header, and then emit a trailer that pads the
3450 /// file out to be a multiple of 16 bytes.
3451 ///
3452 /// struct bc_header {
3453 ///   uint32_t Magic;         // 0x0B17C0DE
3454 ///   uint32_t Version;       // Version, currently always 0.
3455 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
3456 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
3457 ///   uint32_t CPUType;       // CPU specifier.
3458 ///   ... potentially more later ...
3459 /// };
3460 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
3461                                          const Triple &TT) {
3462   unsigned CPUType = ~0U;
3463 
3464   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
3465   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
3466   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
3467   // specific constants here because they are implicitly part of the Darwin ABI.
3468   enum {
3469     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
3470     DARWIN_CPU_TYPE_X86        = 7,
3471     DARWIN_CPU_TYPE_ARM        = 12,
3472     DARWIN_CPU_TYPE_POWERPC    = 18
3473   };
3474 
3475   Triple::ArchType Arch = TT.getArch();
3476   if (Arch == Triple::x86_64)
3477     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
3478   else if (Arch == Triple::x86)
3479     CPUType = DARWIN_CPU_TYPE_X86;
3480   else if (Arch == Triple::ppc)
3481     CPUType = DARWIN_CPU_TYPE_POWERPC;
3482   else if (Arch == Triple::ppc64)
3483     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
3484   else if (Arch == Triple::arm || Arch == Triple::thumb)
3485     CPUType = DARWIN_CPU_TYPE_ARM;
3486 
3487   // Traditional Bitcode starts after header.
3488   assert(Buffer.size() >= BWH_HeaderSize &&
3489          "Expected header size to be reserved");
3490   unsigned BCOffset = BWH_HeaderSize;
3491   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
3492 
3493   // Write the magic and version.
3494   unsigned Position = 0;
3495   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
3496   writeInt32ToBuffer(0, Buffer, Position); // Version.
3497   writeInt32ToBuffer(BCOffset, Buffer, Position);
3498   writeInt32ToBuffer(BCSize, Buffer, Position);
3499   writeInt32ToBuffer(CPUType, Buffer, Position);
3500 
3501   // If the file is not a multiple of 16 bytes, insert dummy padding.
3502   while (Buffer.size() & 15)
3503     Buffer.push_back(0);
3504 }
3505 
3506 /// Helper to write the header common to all bitcode files.
3507 void BitcodeWriter::writeBitcodeHeader() {
3508   // Emit the file header.
3509   stream().Emit((unsigned)'B', 8);
3510   stream().Emit((unsigned)'C', 8);
3511   stream().Emit(0x0, 4);
3512   stream().Emit(0xC, 4);
3513   stream().Emit(0xE, 4);
3514   stream().Emit(0xD, 4);
3515 }
3516 
3517 /// WriteBitcodeToFile - Write the specified module to the specified output
3518 /// stream.
3519 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out,
3520                               bool ShouldPreserveUseListOrder,
3521                               const ModuleSummaryIndex *Index,
3522                               bool GenerateHash) {
3523   SmallVector<char, 0> Buffer;
3524   Buffer.reserve(256*1024);
3525 
3526   // If this is darwin or another generic macho target, reserve space for the
3527   // header.
3528   Triple TT(M->getTargetTriple());
3529   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
3530     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
3531 
3532   // Emit the module into the buffer.
3533   ModuleBitcodeWriter ModuleWriter(M, &Buffer, ShouldPreserveUseListOrder,
3534                                    Index, GenerateHash);
3535   ModuleWriter.write();
3536 
3537   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
3538     emitDarwinBCHeaderAndTrailer(Buffer, TT);
3539 
3540   // Write the generated bitstream to "Out".
3541   Out.write((char*)&Buffer.front(), Buffer.size());
3542 }
3543 
3544 void IndexBitcodeWriter::writeIndex() {
3545   stream().EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
3546 
3547   SmallVector<unsigned, 1> Vals;
3548   unsigned CurVersion = 1;
3549   Vals.push_back(CurVersion);
3550   stream().EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
3551 
3552   // If we have a VST, write the VSTOFFSET record placeholder.
3553   writeValueSymbolTableForwardDecl();
3554 
3555   // Write the module paths in the combined index.
3556   writeModStrings();
3557 
3558   // Write the summary combined index records.
3559   writeCombinedGlobalValueSummary();
3560 
3561   // Need a special VST writer for the combined index (we don't have a
3562   // real VST and real values when this is invoked).
3563   writeCombinedValueSymbolTable();
3564 
3565   stream().ExitBlock();
3566 }
3567 
3568 // Write the specified module summary index to the given raw output stream,
3569 // where it will be written in a new bitcode block. This is used when
3570 // writing the combined index file for ThinLTO.
3571 void llvm::WriteIndexToFile(const ModuleSummaryIndex &Index, raw_ostream &Out) {
3572   SmallVector<char, 0> Buffer;
3573   Buffer.reserve(256 * 1024);
3574 
3575   IndexBitcodeWriter IndexWriter(&Buffer, &Index);
3576   IndexWriter.write();
3577 
3578   Out.write((char *)&Buffer.front(), Buffer.size());
3579 }
3580