xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision 2d5487cf446f9a58f6d2f76df33102423c83f285)
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/CommandLine.h"
32 #include "llvm/Support/ErrorHandling.h"
33 #include "llvm/Support/MathExtras.h"
34 #include "llvm/Support/Program.h"
35 #include "llvm/Support/raw_ostream.h"
36 #include "llvm/Support/SHA1.h"
37 #include <cctype>
38 #include <map>
39 using namespace llvm;
40 
41 /// These are manifest constants used by the bitcode writer. They do not need to
42 /// be kept in sync with the reader, but need to be consistent within this file.
43 enum {
44   // VALUE_SYMTAB_BLOCK abbrev id's.
45   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
46   VST_ENTRY_7_ABBREV,
47   VST_ENTRY_6_ABBREV,
48   VST_BBENTRY_6_ABBREV,
49 
50   // CONSTANTS_BLOCK abbrev id's.
51   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
52   CONSTANTS_INTEGER_ABBREV,
53   CONSTANTS_CE_CAST_Abbrev,
54   CONSTANTS_NULL_Abbrev,
55 
56   // FUNCTION_BLOCK abbrev id's.
57   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
58   FUNCTION_INST_BINOP_ABBREV,
59   FUNCTION_INST_BINOP_FLAGS_ABBREV,
60   FUNCTION_INST_CAST_ABBREV,
61   FUNCTION_INST_RET_VOID_ABBREV,
62   FUNCTION_INST_RET_VAL_ABBREV,
63   FUNCTION_INST_UNREACHABLE_ABBREV,
64   FUNCTION_INST_GEP_ABBREV,
65 };
66 
67 static unsigned GetEncodedCastOpcode(unsigned Opcode) {
68   switch (Opcode) {
69   default: llvm_unreachable("Unknown cast instruction!");
70   case Instruction::Trunc   : return bitc::CAST_TRUNC;
71   case Instruction::ZExt    : return bitc::CAST_ZEXT;
72   case Instruction::SExt    : return bitc::CAST_SEXT;
73   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
74   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
75   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
76   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
77   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
78   case Instruction::FPExt   : return bitc::CAST_FPEXT;
79   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
80   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
81   case Instruction::BitCast : return bitc::CAST_BITCAST;
82   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
83   }
84 }
85 
86 static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
87   switch (Opcode) {
88   default: llvm_unreachable("Unknown binary instruction!");
89   case Instruction::Add:
90   case Instruction::FAdd: return bitc::BINOP_ADD;
91   case Instruction::Sub:
92   case Instruction::FSub: return bitc::BINOP_SUB;
93   case Instruction::Mul:
94   case Instruction::FMul: return bitc::BINOP_MUL;
95   case Instruction::UDiv: return bitc::BINOP_UDIV;
96   case Instruction::FDiv:
97   case Instruction::SDiv: return bitc::BINOP_SDIV;
98   case Instruction::URem: return bitc::BINOP_UREM;
99   case Instruction::FRem:
100   case Instruction::SRem: return bitc::BINOP_SREM;
101   case Instruction::Shl:  return bitc::BINOP_SHL;
102   case Instruction::LShr: return bitc::BINOP_LSHR;
103   case Instruction::AShr: return bitc::BINOP_ASHR;
104   case Instruction::And:  return bitc::BINOP_AND;
105   case Instruction::Or:   return bitc::BINOP_OR;
106   case Instruction::Xor:  return bitc::BINOP_XOR;
107   }
108 }
109 
110 static unsigned GetEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
111   switch (Op) {
112   default: llvm_unreachable("Unknown RMW operation!");
113   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
114   case AtomicRMWInst::Add: return bitc::RMW_ADD;
115   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
116   case AtomicRMWInst::And: return bitc::RMW_AND;
117   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
118   case AtomicRMWInst::Or: return bitc::RMW_OR;
119   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
120   case AtomicRMWInst::Max: return bitc::RMW_MAX;
121   case AtomicRMWInst::Min: return bitc::RMW_MIN;
122   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
123   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
124   }
125 }
126 
127 static unsigned GetEncodedOrdering(AtomicOrdering Ordering) {
128   switch (Ordering) {
129   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
130   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
131   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
132   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
133   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
134   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
135   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
136   }
137   llvm_unreachable("Invalid ordering");
138 }
139 
140 static unsigned GetEncodedSynchScope(SynchronizationScope SynchScope) {
141   switch (SynchScope) {
142   case SingleThread: return bitc::SYNCHSCOPE_SINGLETHREAD;
143   case CrossThread: return bitc::SYNCHSCOPE_CROSSTHREAD;
144   }
145   llvm_unreachable("Invalid synch scope");
146 }
147 
148 static void WriteStringRecord(unsigned Code, StringRef Str,
149                               unsigned AbbrevToUse, BitstreamWriter &Stream) {
150   SmallVector<unsigned, 64> Vals;
151 
152   // Code: [strchar x N]
153   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
154     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
155       AbbrevToUse = 0;
156     Vals.push_back(Str[i]);
157   }
158 
159   // Emit the finished record.
160   Stream.EmitRecord(Code, Vals, AbbrevToUse);
161 }
162 
163 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
164   switch (Kind) {
165   case Attribute::Alignment:
166     return bitc::ATTR_KIND_ALIGNMENT;
167   case Attribute::AlwaysInline:
168     return bitc::ATTR_KIND_ALWAYS_INLINE;
169   case Attribute::ArgMemOnly:
170     return bitc::ATTR_KIND_ARGMEMONLY;
171   case Attribute::Builtin:
172     return bitc::ATTR_KIND_BUILTIN;
173   case Attribute::ByVal:
174     return bitc::ATTR_KIND_BY_VAL;
175   case Attribute::Convergent:
176     return bitc::ATTR_KIND_CONVERGENT;
177   case Attribute::InAlloca:
178     return bitc::ATTR_KIND_IN_ALLOCA;
179   case Attribute::Cold:
180     return bitc::ATTR_KIND_COLD;
181   case Attribute::InaccessibleMemOnly:
182     return bitc::ATTR_KIND_INACCESSIBLEMEM_ONLY;
183   case Attribute::InaccessibleMemOrArgMemOnly:
184     return bitc::ATTR_KIND_INACCESSIBLEMEM_OR_ARGMEMONLY;
185   case Attribute::InlineHint:
186     return bitc::ATTR_KIND_INLINE_HINT;
187   case Attribute::InReg:
188     return bitc::ATTR_KIND_IN_REG;
189   case Attribute::JumpTable:
190     return bitc::ATTR_KIND_JUMP_TABLE;
191   case Attribute::MinSize:
192     return bitc::ATTR_KIND_MIN_SIZE;
193   case Attribute::Naked:
194     return bitc::ATTR_KIND_NAKED;
195   case Attribute::Nest:
196     return bitc::ATTR_KIND_NEST;
197   case Attribute::NoAlias:
198     return bitc::ATTR_KIND_NO_ALIAS;
199   case Attribute::NoBuiltin:
200     return bitc::ATTR_KIND_NO_BUILTIN;
201   case Attribute::NoCapture:
202     return bitc::ATTR_KIND_NO_CAPTURE;
203   case Attribute::NoDuplicate:
204     return bitc::ATTR_KIND_NO_DUPLICATE;
205   case Attribute::NoImplicitFloat:
206     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
207   case Attribute::NoInline:
208     return bitc::ATTR_KIND_NO_INLINE;
209   case Attribute::NoRecurse:
210     return bitc::ATTR_KIND_NO_RECURSE;
211   case Attribute::NonLazyBind:
212     return bitc::ATTR_KIND_NON_LAZY_BIND;
213   case Attribute::NonNull:
214     return bitc::ATTR_KIND_NON_NULL;
215   case Attribute::Dereferenceable:
216     return bitc::ATTR_KIND_DEREFERENCEABLE;
217   case Attribute::DereferenceableOrNull:
218     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
219   case Attribute::NoRedZone:
220     return bitc::ATTR_KIND_NO_RED_ZONE;
221   case Attribute::NoReturn:
222     return bitc::ATTR_KIND_NO_RETURN;
223   case Attribute::NoUnwind:
224     return bitc::ATTR_KIND_NO_UNWIND;
225   case Attribute::OptimizeForSize:
226     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
227   case Attribute::OptimizeNone:
228     return bitc::ATTR_KIND_OPTIMIZE_NONE;
229   case Attribute::ReadNone:
230     return bitc::ATTR_KIND_READ_NONE;
231   case Attribute::ReadOnly:
232     return bitc::ATTR_KIND_READ_ONLY;
233   case Attribute::Returned:
234     return bitc::ATTR_KIND_RETURNED;
235   case Attribute::ReturnsTwice:
236     return bitc::ATTR_KIND_RETURNS_TWICE;
237   case Attribute::SExt:
238     return bitc::ATTR_KIND_S_EXT;
239   case Attribute::StackAlignment:
240     return bitc::ATTR_KIND_STACK_ALIGNMENT;
241   case Attribute::StackProtect:
242     return bitc::ATTR_KIND_STACK_PROTECT;
243   case Attribute::StackProtectReq:
244     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
245   case Attribute::StackProtectStrong:
246     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
247   case Attribute::SafeStack:
248     return bitc::ATTR_KIND_SAFESTACK;
249   case Attribute::StructRet:
250     return bitc::ATTR_KIND_STRUCT_RET;
251   case Attribute::SanitizeAddress:
252     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
253   case Attribute::SanitizeThread:
254     return bitc::ATTR_KIND_SANITIZE_THREAD;
255   case Attribute::SanitizeMemory:
256     return bitc::ATTR_KIND_SANITIZE_MEMORY;
257   case Attribute::SwiftError:
258     return bitc::ATTR_KIND_SWIFT_ERROR;
259   case Attribute::SwiftSelf:
260     return bitc::ATTR_KIND_SWIFT_SELF;
261   case Attribute::UWTable:
262     return bitc::ATTR_KIND_UW_TABLE;
263   case Attribute::ZExt:
264     return bitc::ATTR_KIND_Z_EXT;
265   case Attribute::EndAttrKinds:
266     llvm_unreachable("Can not encode end-attribute kinds marker.");
267   case Attribute::None:
268     llvm_unreachable("Can not encode none-attribute.");
269   }
270 
271   llvm_unreachable("Trying to encode unknown attribute");
272 }
273 
274 static void WriteAttributeGroupTable(const ValueEnumerator &VE,
275                                      BitstreamWriter &Stream) {
276   const std::vector<AttributeSet> &AttrGrps = VE.getAttributeGroups();
277   if (AttrGrps.empty()) return;
278 
279   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
280 
281   SmallVector<uint64_t, 64> Record;
282   for (unsigned i = 0, e = AttrGrps.size(); i != e; ++i) {
283     AttributeSet AS = AttrGrps[i];
284     for (unsigned i = 0, e = AS.getNumSlots(); i != e; ++i) {
285       AttributeSet A = AS.getSlotAttributes(i);
286 
287       Record.push_back(VE.getAttributeGroupID(A));
288       Record.push_back(AS.getSlotIndex(i));
289 
290       for (AttributeSet::iterator I = AS.begin(0), E = AS.end(0);
291            I != E; ++I) {
292         Attribute Attr = *I;
293         if (Attr.isEnumAttribute()) {
294           Record.push_back(0);
295           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
296         } else if (Attr.isIntAttribute()) {
297           Record.push_back(1);
298           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
299           Record.push_back(Attr.getValueAsInt());
300         } else {
301           StringRef Kind = Attr.getKindAsString();
302           StringRef Val = Attr.getValueAsString();
303 
304           Record.push_back(Val.empty() ? 3 : 4);
305           Record.append(Kind.begin(), Kind.end());
306           Record.push_back(0);
307           if (!Val.empty()) {
308             Record.append(Val.begin(), Val.end());
309             Record.push_back(0);
310           }
311         }
312       }
313 
314       Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
315       Record.clear();
316     }
317   }
318 
319   Stream.ExitBlock();
320 }
321 
322 static void WriteAttributeTable(const ValueEnumerator &VE,
323                                 BitstreamWriter &Stream) {
324   const std::vector<AttributeSet> &Attrs = VE.getAttributes();
325   if (Attrs.empty()) return;
326 
327   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
328 
329   SmallVector<uint64_t, 64> Record;
330   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
331     const AttributeSet &A = Attrs[i];
332     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i)
333       Record.push_back(VE.getAttributeGroupID(A.getSlotAttributes(i)));
334 
335     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
336     Record.clear();
337   }
338 
339   Stream.ExitBlock();
340 }
341 
342 /// WriteTypeTable - Write out the type table for a module.
343 static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
344   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
345 
346   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
347   SmallVector<uint64_t, 64> TypeVals;
348 
349   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
350 
351   // Abbrev for TYPE_CODE_POINTER.
352   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
353   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
354   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
355   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
356   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
357 
358   // Abbrev for TYPE_CODE_FUNCTION.
359   Abbv = new BitCodeAbbrev();
360   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
361   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
362   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
363   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
364 
365   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
366 
367   // Abbrev for TYPE_CODE_STRUCT_ANON.
368   Abbv = new BitCodeAbbrev();
369   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
370   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
371   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
372   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
373 
374   unsigned StructAnonAbbrev = Stream.EmitAbbrev(Abbv);
375 
376   // Abbrev for TYPE_CODE_STRUCT_NAME.
377   Abbv = new BitCodeAbbrev();
378   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
379   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
380   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
381   unsigned StructNameAbbrev = Stream.EmitAbbrev(Abbv);
382 
383   // Abbrev for TYPE_CODE_STRUCT_NAMED.
384   Abbv = new BitCodeAbbrev();
385   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
386   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
387   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
388   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
389 
390   unsigned StructNamedAbbrev = Stream.EmitAbbrev(Abbv);
391 
392   // Abbrev for TYPE_CODE_ARRAY.
393   Abbv = new BitCodeAbbrev();
394   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
395   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
396   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
397 
398   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
399 
400   // Emit an entry count so the reader can reserve space.
401   TypeVals.push_back(TypeList.size());
402   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
403   TypeVals.clear();
404 
405   // Loop over all of the types, emitting each in turn.
406   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
407     Type *T = TypeList[i];
408     int AbbrevToUse = 0;
409     unsigned Code = 0;
410 
411     switch (T->getTypeID()) {
412     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
413     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
414     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
415     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
416     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
417     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
418     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
419     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
420     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
421     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
422     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
423     case Type::IntegerTyID:
424       // INTEGER: [width]
425       Code = bitc::TYPE_CODE_INTEGER;
426       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
427       break;
428     case Type::PointerTyID: {
429       PointerType *PTy = cast<PointerType>(T);
430       // POINTER: [pointee type, address space]
431       Code = bitc::TYPE_CODE_POINTER;
432       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
433       unsigned AddressSpace = PTy->getAddressSpace();
434       TypeVals.push_back(AddressSpace);
435       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
436       break;
437     }
438     case Type::FunctionTyID: {
439       FunctionType *FT = cast<FunctionType>(T);
440       // FUNCTION: [isvararg, retty, paramty x N]
441       Code = bitc::TYPE_CODE_FUNCTION;
442       TypeVals.push_back(FT->isVarArg());
443       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
444       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
445         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
446       AbbrevToUse = FunctionAbbrev;
447       break;
448     }
449     case Type::StructTyID: {
450       StructType *ST = cast<StructType>(T);
451       // STRUCT: [ispacked, eltty x N]
452       TypeVals.push_back(ST->isPacked());
453       // Output all of the element types.
454       for (StructType::element_iterator I = ST->element_begin(),
455            E = ST->element_end(); I != E; ++I)
456         TypeVals.push_back(VE.getTypeID(*I));
457 
458       if (ST->isLiteral()) {
459         Code = bitc::TYPE_CODE_STRUCT_ANON;
460         AbbrevToUse = StructAnonAbbrev;
461       } else {
462         if (ST->isOpaque()) {
463           Code = bitc::TYPE_CODE_OPAQUE;
464         } else {
465           Code = bitc::TYPE_CODE_STRUCT_NAMED;
466           AbbrevToUse = StructNamedAbbrev;
467         }
468 
469         // Emit the name if it is present.
470         if (!ST->getName().empty())
471           WriteStringRecord(bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
472                             StructNameAbbrev, Stream);
473       }
474       break;
475     }
476     case Type::ArrayTyID: {
477       ArrayType *AT = cast<ArrayType>(T);
478       // ARRAY: [numelts, eltty]
479       Code = bitc::TYPE_CODE_ARRAY;
480       TypeVals.push_back(AT->getNumElements());
481       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
482       AbbrevToUse = ArrayAbbrev;
483       break;
484     }
485     case Type::VectorTyID: {
486       VectorType *VT = cast<VectorType>(T);
487       // VECTOR [numelts, eltty]
488       Code = bitc::TYPE_CODE_VECTOR;
489       TypeVals.push_back(VT->getNumElements());
490       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
491       break;
492     }
493     }
494 
495     // Emit the finished record.
496     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
497     TypeVals.clear();
498   }
499 
500   Stream.ExitBlock();
501 }
502 
503 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
504   switch (Linkage) {
505   case GlobalValue::ExternalLinkage:
506     return 0;
507   case GlobalValue::WeakAnyLinkage:
508     return 16;
509   case GlobalValue::AppendingLinkage:
510     return 2;
511   case GlobalValue::InternalLinkage:
512     return 3;
513   case GlobalValue::LinkOnceAnyLinkage:
514     return 18;
515   case GlobalValue::ExternalWeakLinkage:
516     return 7;
517   case GlobalValue::CommonLinkage:
518     return 8;
519   case GlobalValue::PrivateLinkage:
520     return 9;
521   case GlobalValue::WeakODRLinkage:
522     return 17;
523   case GlobalValue::LinkOnceODRLinkage:
524     return 19;
525   case GlobalValue::AvailableExternallyLinkage:
526     return 12;
527   }
528   llvm_unreachable("Invalid linkage");
529 }
530 
531 static unsigned getEncodedLinkage(const GlobalValue &GV) {
532   return getEncodedLinkage(GV.getLinkage());
533 }
534 
535 static unsigned getEncodedVisibility(const GlobalValue &GV) {
536   switch (GV.getVisibility()) {
537   case GlobalValue::DefaultVisibility:   return 0;
538   case GlobalValue::HiddenVisibility:    return 1;
539   case GlobalValue::ProtectedVisibility: return 2;
540   }
541   llvm_unreachable("Invalid visibility");
542 }
543 
544 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
545   switch (GV.getDLLStorageClass()) {
546   case GlobalValue::DefaultStorageClass:   return 0;
547   case GlobalValue::DLLImportStorageClass: return 1;
548   case GlobalValue::DLLExportStorageClass: return 2;
549   }
550   llvm_unreachable("Invalid DLL storage class");
551 }
552 
553 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
554   switch (GV.getThreadLocalMode()) {
555     case GlobalVariable::NotThreadLocal:         return 0;
556     case GlobalVariable::GeneralDynamicTLSModel: return 1;
557     case GlobalVariable::LocalDynamicTLSModel:   return 2;
558     case GlobalVariable::InitialExecTLSModel:    return 3;
559     case GlobalVariable::LocalExecTLSModel:      return 4;
560   }
561   llvm_unreachable("Invalid TLS model");
562 }
563 
564 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
565   switch (C.getSelectionKind()) {
566   case Comdat::Any:
567     return bitc::COMDAT_SELECTION_KIND_ANY;
568   case Comdat::ExactMatch:
569     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
570   case Comdat::Largest:
571     return bitc::COMDAT_SELECTION_KIND_LARGEST;
572   case Comdat::NoDuplicates:
573     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
574   case Comdat::SameSize:
575     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
576   }
577   llvm_unreachable("Invalid selection kind");
578 }
579 
580 static void writeComdats(const ValueEnumerator &VE, BitstreamWriter &Stream) {
581   SmallVector<unsigned, 64> Vals;
582   for (const Comdat *C : VE.getComdats()) {
583     // COMDAT: [selection_kind, name]
584     Vals.push_back(getEncodedComdatSelectionKind(*C));
585     size_t Size = C->getName().size();
586     assert(isUInt<32>(Size));
587     Vals.push_back(Size);
588     for (char Chr : C->getName())
589       Vals.push_back((unsigned char)Chr);
590     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
591     Vals.clear();
592   }
593 }
594 
595 /// Write a record that will eventually hold the word offset of the
596 /// module-level VST. For now the offset is 0, which will be backpatched
597 /// after the real VST is written. Returns the bit offset to backpatch.
598 static uint64_t WriteValueSymbolTableForwardDecl(BitstreamWriter &Stream) {
599   // Write a placeholder value in for the offset of the real VST,
600   // which is written after the function blocks so that it can include
601   // the offset of each function. The placeholder offset will be
602   // updated when the real VST is written.
603   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
604   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
605   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
606   // hold the real VST offset. Must use fixed instead of VBR as we don't
607   // know how many VBR chunks to reserve ahead of time.
608   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
609   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(Abbv);
610 
611   // Emit the placeholder
612   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
613   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
614 
615   // Compute and return the bit offset to the placeholder, which will be
616   // patched when the real VST is written. We can simply subtract the 32-bit
617   // fixed size from the current bit number to get the location to backpatch.
618   return Stream.GetCurrentBitNo() - 32;
619 }
620 
621 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
622 
623 /// Determine the encoding to use for the given string name and length.
624 static StringEncoding getStringEncoding(const char *Str, unsigned StrLen) {
625   bool isChar6 = true;
626   for (const char *C = Str, *E = C + StrLen; C != E; ++C) {
627     if (isChar6)
628       isChar6 = BitCodeAbbrevOp::isChar6(*C);
629     if ((unsigned char)*C & 128)
630       // don't bother scanning the rest.
631       return SE_Fixed8;
632   }
633   if (isChar6)
634     return SE_Char6;
635   else
636     return SE_Fixed7;
637 }
638 
639 /// Emit top-level description of module, including target triple, inline asm,
640 /// descriptors for global variables, and function prototype info.
641 /// Returns the bit offset to backpatch with the location of the real VST.
642 static uint64_t WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
643                                 BitstreamWriter &Stream) {
644   // Emit various pieces of data attached to a module.
645   if (!M->getTargetTriple().empty())
646     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
647                       0/*TODO*/, Stream);
648   const std::string &DL = M->getDataLayoutStr();
649   if (!DL.empty())
650     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/, Stream);
651   if (!M->getModuleInlineAsm().empty())
652     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
653                       0/*TODO*/, Stream);
654 
655   // Emit information about sections and GC, computing how many there are. Also
656   // compute the maximum alignment value.
657   std::map<std::string, unsigned> SectionMap;
658   std::map<std::string, unsigned> GCMap;
659   unsigned MaxAlignment = 0;
660   unsigned MaxGlobalType = 0;
661   for (const GlobalValue &GV : M->globals()) {
662     MaxAlignment = std::max(MaxAlignment, GV.getAlignment());
663     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
664     if (GV.hasSection()) {
665       // Give section names unique ID's.
666       unsigned &Entry = SectionMap[GV.getSection()];
667       if (!Entry) {
668         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
669                           0/*TODO*/, Stream);
670         Entry = SectionMap.size();
671       }
672     }
673   }
674   for (const Function &F : *M) {
675     MaxAlignment = std::max(MaxAlignment, F.getAlignment());
676     if (F.hasSection()) {
677       // Give section names unique ID's.
678       unsigned &Entry = SectionMap[F.getSection()];
679       if (!Entry) {
680         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
681                           0/*TODO*/, Stream);
682         Entry = SectionMap.size();
683       }
684     }
685     if (F.hasGC()) {
686       // Same for GC names.
687       unsigned &Entry = GCMap[F.getGC()];
688       if (!Entry) {
689         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F.getGC(),
690                           0/*TODO*/, Stream);
691         Entry = GCMap.size();
692       }
693     }
694   }
695 
696   // Emit abbrev for globals, now that we know # sections and max alignment.
697   unsigned SimpleGVarAbbrev = 0;
698   if (!M->global_empty()) {
699     // Add an abbrev for common globals with no visibility or thread localness.
700     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
701     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
702     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
703                               Log2_32_Ceil(MaxGlobalType+1)));
704     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
705                                                            //| explicitType << 1
706                                                            //| constant
707     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
708     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
709     if (MaxAlignment == 0)                                 // Alignment.
710       Abbv->Add(BitCodeAbbrevOp(0));
711     else {
712       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
713       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
714                                Log2_32_Ceil(MaxEncAlignment+1)));
715     }
716     if (SectionMap.empty())                                    // Section.
717       Abbv->Add(BitCodeAbbrevOp(0));
718     else
719       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
720                                Log2_32_Ceil(SectionMap.size()+1)));
721     // Don't bother emitting vis + thread local.
722     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
723   }
724 
725   // Emit the global variable information.
726   SmallVector<unsigned, 64> Vals;
727   for (const GlobalVariable &GV : M->globals()) {
728     unsigned AbbrevToUse = 0;
729 
730     // GLOBALVAR: [type, isconst, initid,
731     //             linkage, alignment, section, visibility, threadlocal,
732     //             unnamed_addr, externally_initialized, dllstorageclass,
733     //             comdat]
734     Vals.push_back(VE.getTypeID(GV.getValueType()));
735     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
736     Vals.push_back(GV.isDeclaration() ? 0 :
737                    (VE.getValueID(GV.getInitializer()) + 1));
738     Vals.push_back(getEncodedLinkage(GV));
739     Vals.push_back(Log2_32(GV.getAlignment())+1);
740     Vals.push_back(GV.hasSection() ? SectionMap[GV.getSection()] : 0);
741     if (GV.isThreadLocal() ||
742         GV.getVisibility() != GlobalValue::DefaultVisibility ||
743         GV.hasUnnamedAddr() || GV.isExternallyInitialized() ||
744         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
745         GV.hasComdat()) {
746       Vals.push_back(getEncodedVisibility(GV));
747       Vals.push_back(getEncodedThreadLocalMode(GV));
748       Vals.push_back(GV.hasUnnamedAddr());
749       Vals.push_back(GV.isExternallyInitialized());
750       Vals.push_back(getEncodedDLLStorageClass(GV));
751       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
752     } else {
753       AbbrevToUse = SimpleGVarAbbrev;
754     }
755 
756     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
757     Vals.clear();
758   }
759 
760   // Emit the function proto information.
761   for (const Function &F : *M) {
762     // FUNCTION:  [type, callingconv, isproto, linkage, paramattrs, alignment,
763     //             section, visibility, gc, unnamed_addr, prologuedata,
764     //             dllstorageclass, comdat, prefixdata, personalityfn]
765     Vals.push_back(VE.getTypeID(F.getFunctionType()));
766     Vals.push_back(F.getCallingConv());
767     Vals.push_back(F.isDeclaration());
768     Vals.push_back(getEncodedLinkage(F));
769     Vals.push_back(VE.getAttributeID(F.getAttributes()));
770     Vals.push_back(Log2_32(F.getAlignment())+1);
771     Vals.push_back(F.hasSection() ? SectionMap[F.getSection()] : 0);
772     Vals.push_back(getEncodedVisibility(F));
773     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
774     Vals.push_back(F.hasUnnamedAddr());
775     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
776                                        : 0);
777     Vals.push_back(getEncodedDLLStorageClass(F));
778     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
779     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
780                                      : 0);
781     Vals.push_back(
782         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
783 
784     unsigned AbbrevToUse = 0;
785     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
786     Vals.clear();
787   }
788 
789   // Emit the alias information.
790   for (const GlobalAlias &A : M->aliases()) {
791     // ALIAS: [alias type, aliasee val#, linkage, visibility]
792     Vals.push_back(VE.getTypeID(A.getValueType()));
793     Vals.push_back(A.getType()->getAddressSpace());
794     Vals.push_back(VE.getValueID(A.getAliasee()));
795     Vals.push_back(getEncodedLinkage(A));
796     Vals.push_back(getEncodedVisibility(A));
797     Vals.push_back(getEncodedDLLStorageClass(A));
798     Vals.push_back(getEncodedThreadLocalMode(A));
799     Vals.push_back(A.hasUnnamedAddr());
800     unsigned AbbrevToUse = 0;
801     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
802     Vals.clear();
803   }
804 
805   // Emit the ifunc information.
806   for (const GlobalIFunc &I : M->ifuncs()) {
807     // IFUNC: [ifunc type, address space, resolver val#, linkage, visibility]
808     Vals.push_back(VE.getTypeID(I.getValueType()));
809     Vals.push_back(I.getType()->getAddressSpace());
810     Vals.push_back(VE.getValueID(I.getResolver()));
811     Vals.push_back(getEncodedLinkage(I));
812     Vals.push_back(getEncodedVisibility(I));
813     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
814     Vals.clear();
815   }
816 
817   // Emit the module's source file name.
818   {
819     StringEncoding Bits = getStringEncoding(M->getSourceFileName().data(),
820                                             M->getSourceFileName().size());
821     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
822     if (Bits == SE_Char6)
823       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
824     else if (Bits == SE_Fixed7)
825       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
826 
827     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
828     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
829     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
830     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
831     Abbv->Add(AbbrevOpToUse);
832     unsigned FilenameAbbrev = Stream.EmitAbbrev(Abbv);
833 
834     for (const auto P : M->getSourceFileName())
835       Vals.push_back((unsigned char)P);
836 
837     // Emit the finished record.
838     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
839     Vals.clear();
840   }
841 
842   // If we have a VST, write the VSTOFFSET record placeholder and return
843   // its offset.
844   if (M->getValueSymbolTable().empty())
845     return 0;
846   return WriteValueSymbolTableForwardDecl(Stream);
847 }
848 
849 static uint64_t GetOptimizationFlags(const Value *V) {
850   uint64_t Flags = 0;
851 
852   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
853     if (OBO->hasNoSignedWrap())
854       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
855     if (OBO->hasNoUnsignedWrap())
856       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
857   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
858     if (PEO->isExact())
859       Flags |= 1 << bitc::PEO_EXACT;
860   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
861     if (FPMO->hasUnsafeAlgebra())
862       Flags |= FastMathFlags::UnsafeAlgebra;
863     if (FPMO->hasNoNaNs())
864       Flags |= FastMathFlags::NoNaNs;
865     if (FPMO->hasNoInfs())
866       Flags |= FastMathFlags::NoInfs;
867     if (FPMO->hasNoSignedZeros())
868       Flags |= FastMathFlags::NoSignedZeros;
869     if (FPMO->hasAllowReciprocal())
870       Flags |= FastMathFlags::AllowReciprocal;
871   }
872 
873   return Flags;
874 }
875 
876 static void writeValueAsMetadata(const ValueAsMetadata *MD,
877                                  const ValueEnumerator &VE,
878                                  BitstreamWriter &Stream,
879                                  SmallVectorImpl<uint64_t> &Record) {
880   // Mimic an MDNode with a value as one operand.
881   Value *V = MD->getValue();
882   Record.push_back(VE.getTypeID(V->getType()));
883   Record.push_back(VE.getValueID(V));
884   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
885   Record.clear();
886 }
887 
888 static void writeMDTuple(const MDTuple *N, const ValueEnumerator &VE,
889                          BitstreamWriter &Stream,
890                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
891   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
892     Metadata *MD = N->getOperand(i);
893     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
894            "Unexpected function-local metadata");
895     Record.push_back(VE.getMetadataOrNullID(MD));
896   }
897   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
898                                     : bitc::METADATA_NODE,
899                     Record, Abbrev);
900   Record.clear();
901 }
902 
903 static unsigned createDILocationAbbrev(BitstreamWriter &Stream) {
904   // Assume the column is usually under 128, and always output the inlined-at
905   // location (it's never more expensive than building an array size 1).
906   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
907   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
908   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
909   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
910   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
911   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
912   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
913   return Stream.EmitAbbrev(Abbv);
914 }
915 
916 static void writeDILocation(const DILocation *N, const ValueEnumerator &VE,
917                             BitstreamWriter &Stream,
918                             SmallVectorImpl<uint64_t> &Record,
919                             unsigned &Abbrev) {
920   if (!Abbrev)
921     Abbrev = createDILocationAbbrev(Stream);
922 
923   Record.push_back(N->isDistinct());
924   Record.push_back(N->getLine());
925   Record.push_back(N->getColumn());
926   Record.push_back(VE.getMetadataID(N->getScope()));
927   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
928 
929   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
930   Record.clear();
931 }
932 
933 static unsigned createGenericDINodeAbbrev(BitstreamWriter &Stream) {
934   // Assume the column is usually under 128, and always output the inlined-at
935   // location (it's never more expensive than building an array size 1).
936   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
937   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
938   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
939   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
940   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
941   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
942   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
943   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
944   return Stream.EmitAbbrev(Abbv);
945 }
946 
947 static void writeGenericDINode(const GenericDINode *N,
948                                const ValueEnumerator &VE,
949                                BitstreamWriter &Stream,
950                                SmallVectorImpl<uint64_t> &Record,
951                                unsigned &Abbrev) {
952   if (!Abbrev)
953     Abbrev = createGenericDINodeAbbrev(Stream);
954 
955   Record.push_back(N->isDistinct());
956   Record.push_back(N->getTag());
957   Record.push_back(0); // Per-tag version field; unused for now.
958 
959   for (auto &I : N->operands())
960     Record.push_back(VE.getMetadataOrNullID(I));
961 
962   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
963   Record.clear();
964 }
965 
966 static uint64_t rotateSign(int64_t I) {
967   uint64_t U = I;
968   return I < 0 ? ~(U << 1) : U << 1;
969 }
970 
971 static void writeDISubrange(const DISubrange *N, const ValueEnumerator &,
972                             BitstreamWriter &Stream,
973                             SmallVectorImpl<uint64_t> &Record,
974                             unsigned Abbrev) {
975   Record.push_back(N->isDistinct());
976   Record.push_back(N->getCount());
977   Record.push_back(rotateSign(N->getLowerBound()));
978 
979   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
980   Record.clear();
981 }
982 
983 static void writeDIEnumerator(const DIEnumerator *N, const ValueEnumerator &VE,
984                               BitstreamWriter &Stream,
985                               SmallVectorImpl<uint64_t> &Record,
986                               unsigned Abbrev) {
987   Record.push_back(N->isDistinct());
988   Record.push_back(rotateSign(N->getValue()));
989   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
990 
991   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
992   Record.clear();
993 }
994 
995 static void writeDIBasicType(const DIBasicType *N, const ValueEnumerator &VE,
996                              BitstreamWriter &Stream,
997                              SmallVectorImpl<uint64_t> &Record,
998                              unsigned Abbrev) {
999   Record.push_back(N->isDistinct());
1000   Record.push_back(N->getTag());
1001   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1002   Record.push_back(N->getSizeInBits());
1003   Record.push_back(N->getAlignInBits());
1004   Record.push_back(N->getEncoding());
1005 
1006   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1007   Record.clear();
1008 }
1009 
1010 static void writeDIDerivedType(const DIDerivedType *N,
1011                                const ValueEnumerator &VE,
1012                                BitstreamWriter &Stream,
1013                                SmallVectorImpl<uint64_t> &Record,
1014                                unsigned Abbrev) {
1015   Record.push_back(N->isDistinct());
1016   Record.push_back(N->getTag());
1017   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1018   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1019   Record.push_back(N->getLine());
1020   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1021   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1022   Record.push_back(N->getSizeInBits());
1023   Record.push_back(N->getAlignInBits());
1024   Record.push_back(N->getOffsetInBits());
1025   Record.push_back(N->getFlags());
1026   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1027 
1028   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1029   Record.clear();
1030 }
1031 
1032 static void writeDICompositeType(const DICompositeType *N,
1033                                  const ValueEnumerator &VE,
1034                                  BitstreamWriter &Stream,
1035                                  SmallVectorImpl<uint64_t> &Record,
1036                                  unsigned Abbrev) {
1037   Record.push_back(N->isDistinct());
1038   Record.push_back(N->getTag());
1039   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1040   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1041   Record.push_back(N->getLine());
1042   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1043   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1044   Record.push_back(N->getSizeInBits());
1045   Record.push_back(N->getAlignInBits());
1046   Record.push_back(N->getOffsetInBits());
1047   Record.push_back(N->getFlags());
1048   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1049   Record.push_back(N->getRuntimeLang());
1050   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1051   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1052   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1053 
1054   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1055   Record.clear();
1056 }
1057 
1058 static void writeDISubroutineType(const DISubroutineType *N,
1059                                   const ValueEnumerator &VE,
1060                                   BitstreamWriter &Stream,
1061                                   SmallVectorImpl<uint64_t> &Record,
1062                                   unsigned Abbrev) {
1063   Record.push_back(N->isDistinct());
1064   Record.push_back(N->getFlags());
1065   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1066 
1067   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1068   Record.clear();
1069 }
1070 
1071 static void writeDIFile(const DIFile *N, const ValueEnumerator &VE,
1072                         BitstreamWriter &Stream,
1073                         SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
1074   Record.push_back(N->isDistinct());
1075   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1076   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1077 
1078   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1079   Record.clear();
1080 }
1081 
1082 static void writeDICompileUnit(const DICompileUnit *N,
1083                                const ValueEnumerator &VE,
1084                                BitstreamWriter &Stream,
1085                                SmallVectorImpl<uint64_t> &Record,
1086                                unsigned Abbrev) {
1087   assert(N->isDistinct() && "Expected distinct compile units");
1088   Record.push_back(/* IsDistinct */ true);
1089   Record.push_back(N->getSourceLanguage());
1090   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1091   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1092   Record.push_back(N->isOptimized());
1093   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1094   Record.push_back(N->getRuntimeVersion());
1095   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1096   Record.push_back(N->getEmissionKind());
1097   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1098   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1099   Record.push_back(VE.getMetadataOrNullID(N->getSubprograms().get()));
1100   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1101   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1102   Record.push_back(N->getDWOId());
1103   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1104 
1105   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1106   Record.clear();
1107 }
1108 
1109 static void writeDISubprogram(const DISubprogram *N, const ValueEnumerator &VE,
1110                               BitstreamWriter &Stream,
1111                               SmallVectorImpl<uint64_t> &Record,
1112                               unsigned Abbrev) {
1113   Record.push_back(N->isDistinct());
1114   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1115   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1116   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1117   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1118   Record.push_back(N->getLine());
1119   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1120   Record.push_back(N->isLocalToUnit());
1121   Record.push_back(N->isDefinition());
1122   Record.push_back(N->getScopeLine());
1123   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1124   Record.push_back(N->getVirtuality());
1125   Record.push_back(N->getVirtualIndex());
1126   Record.push_back(N->getFlags());
1127   Record.push_back(N->isOptimized());
1128   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1129   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1130   Record.push_back(VE.getMetadataOrNullID(N->getVariables().get()));
1131 
1132   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1133   Record.clear();
1134 }
1135 
1136 static void writeDILexicalBlock(const DILexicalBlock *N,
1137                                 const ValueEnumerator &VE,
1138                                 BitstreamWriter &Stream,
1139                                 SmallVectorImpl<uint64_t> &Record,
1140                                 unsigned Abbrev) {
1141   Record.push_back(N->isDistinct());
1142   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1143   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1144   Record.push_back(N->getLine());
1145   Record.push_back(N->getColumn());
1146 
1147   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1148   Record.clear();
1149 }
1150 
1151 static void writeDILexicalBlockFile(const DILexicalBlockFile *N,
1152                                     const ValueEnumerator &VE,
1153                                     BitstreamWriter &Stream,
1154                                     SmallVectorImpl<uint64_t> &Record,
1155                                     unsigned Abbrev) {
1156   Record.push_back(N->isDistinct());
1157   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1158   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1159   Record.push_back(N->getDiscriminator());
1160 
1161   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1162   Record.clear();
1163 }
1164 
1165 static void writeDINamespace(const DINamespace *N, const ValueEnumerator &VE,
1166                              BitstreamWriter &Stream,
1167                              SmallVectorImpl<uint64_t> &Record,
1168                              unsigned Abbrev) {
1169   Record.push_back(N->isDistinct());
1170   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1171   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1172   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1173   Record.push_back(N->getLine());
1174 
1175   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1176   Record.clear();
1177 }
1178 
1179 static void writeDIMacro(const DIMacro *N, const ValueEnumerator &VE,
1180                          BitstreamWriter &Stream,
1181                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
1182   Record.push_back(N->isDistinct());
1183   Record.push_back(N->getMacinfoType());
1184   Record.push_back(N->getLine());
1185   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1186   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1187 
1188   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1189   Record.clear();
1190 }
1191 
1192 static void writeDIMacroFile(const DIMacroFile *N, const ValueEnumerator &VE,
1193                              BitstreamWriter &Stream,
1194                              SmallVectorImpl<uint64_t> &Record,
1195                              unsigned Abbrev) {
1196   Record.push_back(N->isDistinct());
1197   Record.push_back(N->getMacinfoType());
1198   Record.push_back(N->getLine());
1199   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1200   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1201 
1202   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1203   Record.clear();
1204 }
1205 
1206 static void writeDIModule(const DIModule *N, const ValueEnumerator &VE,
1207                           BitstreamWriter &Stream,
1208                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
1209   Record.push_back(N->isDistinct());
1210   for (auto &I : N->operands())
1211     Record.push_back(VE.getMetadataOrNullID(I));
1212 
1213   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1214   Record.clear();
1215 }
1216 
1217 static void writeDITemplateTypeParameter(const DITemplateTypeParameter *N,
1218                                          const ValueEnumerator &VE,
1219                                          BitstreamWriter &Stream,
1220                                          SmallVectorImpl<uint64_t> &Record,
1221                                          unsigned Abbrev) {
1222   Record.push_back(N->isDistinct());
1223   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1224   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1225 
1226   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1227   Record.clear();
1228 }
1229 
1230 static void writeDITemplateValueParameter(const DITemplateValueParameter *N,
1231                                           const ValueEnumerator &VE,
1232                                           BitstreamWriter &Stream,
1233                                           SmallVectorImpl<uint64_t> &Record,
1234                                           unsigned Abbrev) {
1235   Record.push_back(N->isDistinct());
1236   Record.push_back(N->getTag());
1237   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1238   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1239   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1240 
1241   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1242   Record.clear();
1243 }
1244 
1245 static void writeDIGlobalVariable(const DIGlobalVariable *N,
1246                                   const ValueEnumerator &VE,
1247                                   BitstreamWriter &Stream,
1248                                   SmallVectorImpl<uint64_t> &Record,
1249                                   unsigned Abbrev) {
1250   Record.push_back(N->isDistinct());
1251   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1252   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1253   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1254   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1255   Record.push_back(N->getLine());
1256   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1257   Record.push_back(N->isLocalToUnit());
1258   Record.push_back(N->isDefinition());
1259   Record.push_back(VE.getMetadataOrNullID(N->getRawVariable()));
1260   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1261 
1262   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1263   Record.clear();
1264 }
1265 
1266 static void writeDILocalVariable(const DILocalVariable *N,
1267                                  const ValueEnumerator &VE,
1268                                  BitstreamWriter &Stream,
1269                                  SmallVectorImpl<uint64_t> &Record,
1270                                  unsigned Abbrev) {
1271   Record.push_back(N->isDistinct());
1272   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1273   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1274   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1275   Record.push_back(N->getLine());
1276   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1277   Record.push_back(N->getArg());
1278   Record.push_back(N->getFlags());
1279 
1280   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1281   Record.clear();
1282 }
1283 
1284 static void writeDIExpression(const DIExpression *N, const ValueEnumerator &,
1285                               BitstreamWriter &Stream,
1286                               SmallVectorImpl<uint64_t> &Record,
1287                               unsigned Abbrev) {
1288   Record.reserve(N->getElements().size() + 1);
1289 
1290   Record.push_back(N->isDistinct());
1291   Record.append(N->elements_begin(), N->elements_end());
1292 
1293   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
1294   Record.clear();
1295 }
1296 
1297 static void writeDIObjCProperty(const DIObjCProperty *N,
1298                                 const ValueEnumerator &VE,
1299                                 BitstreamWriter &Stream,
1300                                 SmallVectorImpl<uint64_t> &Record,
1301                                 unsigned Abbrev) {
1302   Record.push_back(N->isDistinct());
1303   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1304   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1305   Record.push_back(N->getLine());
1306   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
1307   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
1308   Record.push_back(N->getAttributes());
1309   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1310 
1311   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
1312   Record.clear();
1313 }
1314 
1315 static void writeDIImportedEntity(const DIImportedEntity *N,
1316                                   const ValueEnumerator &VE,
1317                                   BitstreamWriter &Stream,
1318                                   SmallVectorImpl<uint64_t> &Record,
1319                                   unsigned Abbrev) {
1320   Record.push_back(N->isDistinct());
1321   Record.push_back(N->getTag());
1322   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1323   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
1324   Record.push_back(N->getLine());
1325   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1326 
1327   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
1328   Record.clear();
1329 }
1330 
1331 static unsigned createNamedMetadataAbbrev(BitstreamWriter &Stream) {
1332   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1333   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
1334   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1335   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1336   return Stream.EmitAbbrev(Abbv);
1337 }
1338 
1339 static void writeNamedMetadata(const Module &M, const ValueEnumerator &VE,
1340                                BitstreamWriter &Stream,
1341                                SmallVectorImpl<uint64_t> &Record) {
1342   if (M.named_metadata_empty())
1343     return;
1344 
1345   unsigned Abbrev = createNamedMetadataAbbrev(Stream);
1346   for (const NamedMDNode &NMD : M.named_metadata()) {
1347     // Write name.
1348     StringRef Str = NMD.getName();
1349     Record.append(Str.bytes_begin(), Str.bytes_end());
1350     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
1351     Record.clear();
1352 
1353     // Write named metadata operands.
1354     for (const MDNode *N : NMD.operands())
1355       Record.push_back(VE.getMetadataID(N));
1356     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
1357     Record.clear();
1358   }
1359 }
1360 
1361 static unsigned createMetadataStringsAbbrev(BitstreamWriter &Stream) {
1362   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1363   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
1364   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
1365   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
1366   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
1367   return Stream.EmitAbbrev(Abbv);
1368 }
1369 
1370 /// Write out a record for MDString.
1371 ///
1372 /// All the metadata strings in a metadata block are emitted in a single
1373 /// record.  The sizes and strings themselves are shoved into a blob.
1374 static void writeMetadataStrings(ArrayRef<const Metadata *> Strings,
1375                                  BitstreamWriter &Stream,
1376                                  SmallVectorImpl<uint64_t> &Record) {
1377   if (Strings.empty())
1378     return;
1379 
1380   // Start the record with the number of strings.
1381   Record.push_back(bitc::METADATA_STRINGS);
1382   Record.push_back(Strings.size());
1383 
1384   // Emit the sizes of the strings in the blob.
1385   SmallString<256> Blob;
1386   {
1387     BitstreamWriter W(Blob);
1388     for (const Metadata *MD : Strings)
1389       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
1390     W.FlushToWord();
1391   }
1392 
1393   // Add the offset to the strings to the record.
1394   Record.push_back(Blob.size());
1395 
1396   // Add the strings to the blob.
1397   for (const Metadata *MD : Strings)
1398     Blob.append(cast<MDString>(MD)->getString());
1399 
1400   // Emit the final record.
1401   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(Stream), Record, Blob);
1402   Record.clear();
1403 }
1404 
1405 static void writeMetadataRecords(ArrayRef<const Metadata *> MDs,
1406                                  const ValueEnumerator &VE,
1407                                  BitstreamWriter &Stream,
1408                                  SmallVectorImpl<uint64_t> &Record) {
1409   if (MDs.empty())
1410     return;
1411 
1412   // Initialize MDNode abbreviations.
1413 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
1414 #include "llvm/IR/Metadata.def"
1415 
1416   for (const Metadata *MD : MDs) {
1417     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
1418       assert(N->isResolved() && "Expected forward references to be resolved");
1419 
1420       switch (N->getMetadataID()) {
1421       default:
1422         llvm_unreachable("Invalid MDNode subclass");
1423 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
1424   case Metadata::CLASS##Kind:                                                  \
1425     write##CLASS(cast<CLASS>(N), VE, Stream, Record, CLASS##Abbrev);           \
1426     continue;
1427 #include "llvm/IR/Metadata.def"
1428       }
1429     }
1430     writeValueAsMetadata(cast<ValueAsMetadata>(MD), VE, Stream, Record);
1431   }
1432 }
1433 
1434 static void writeModuleMetadata(const Module &M,
1435                                 const ValueEnumerator &VE,
1436                                 BitstreamWriter &Stream) {
1437   if (!VE.hasMDs() && M.named_metadata_empty())
1438     return;
1439 
1440   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1441   SmallVector<uint64_t, 64> Record;
1442   writeMetadataStrings(VE.getMDStrings(), Stream, Record);
1443   writeMetadataRecords(VE.getNonMDStrings(), VE, Stream, Record);
1444   writeNamedMetadata(M, VE, Stream, Record);
1445   Stream.ExitBlock();
1446 }
1447 
1448 static void writeFunctionMetadata(const Function &F, const ValueEnumerator &VE,
1449                                   BitstreamWriter &Stream) {
1450   if (!VE.hasMDs())
1451     return;
1452 
1453   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1454   SmallVector<uint64_t, 64> Record;
1455   writeMetadataStrings(VE.getMDStrings(), Stream, Record);
1456   writeMetadataRecords(VE.getNonMDStrings(), VE, Stream, Record);
1457   Stream.ExitBlock();
1458 }
1459 
1460 static void WriteMetadataAttachment(const Function &F,
1461                                     const ValueEnumerator &VE,
1462                                     BitstreamWriter &Stream) {
1463   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
1464 
1465   SmallVector<uint64_t, 64> Record;
1466 
1467   // Write metadata attachments
1468   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
1469   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
1470   F.getAllMetadata(MDs);
1471   if (!MDs.empty()) {
1472     for (const auto &I : MDs) {
1473       Record.push_back(I.first);
1474       Record.push_back(VE.getMetadataID(I.second));
1475     }
1476     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1477     Record.clear();
1478   }
1479 
1480   for (const BasicBlock &BB : F)
1481     for (const Instruction &I : BB) {
1482       MDs.clear();
1483       I.getAllMetadataOtherThanDebugLoc(MDs);
1484 
1485       // If no metadata, ignore instruction.
1486       if (MDs.empty()) continue;
1487 
1488       Record.push_back(VE.getInstructionID(&I));
1489 
1490       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1491         Record.push_back(MDs[i].first);
1492         Record.push_back(VE.getMetadataID(MDs[i].second));
1493       }
1494       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1495       Record.clear();
1496     }
1497 
1498   Stream.ExitBlock();
1499 }
1500 
1501 static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
1502   SmallVector<uint64_t, 64> Record;
1503 
1504   // Write metadata kinds
1505   // METADATA_KIND - [n x [id, name]]
1506   SmallVector<StringRef, 8> Names;
1507   M->getMDKindNames(Names);
1508 
1509   if (Names.empty()) return;
1510 
1511   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
1512 
1513   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
1514     Record.push_back(MDKindID);
1515     StringRef KName = Names[MDKindID];
1516     Record.append(KName.begin(), KName.end());
1517 
1518     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
1519     Record.clear();
1520   }
1521 
1522   Stream.ExitBlock();
1523 }
1524 
1525 static void WriteOperandBundleTags(const Module *M, BitstreamWriter &Stream) {
1526   // Write metadata kinds
1527   //
1528   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
1529   //
1530   // OPERAND_BUNDLE_TAG - [strchr x N]
1531 
1532   SmallVector<StringRef, 8> Tags;
1533   M->getOperandBundleTags(Tags);
1534 
1535   if (Tags.empty())
1536     return;
1537 
1538   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
1539 
1540   SmallVector<uint64_t, 64> Record;
1541 
1542   for (auto Tag : Tags) {
1543     Record.append(Tag.begin(), Tag.end());
1544 
1545     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
1546     Record.clear();
1547   }
1548 
1549   Stream.ExitBlock();
1550 }
1551 
1552 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1553   if ((int64_t)V >= 0)
1554     Vals.push_back(V << 1);
1555   else
1556     Vals.push_back((-V << 1) | 1);
1557 }
1558 
1559 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
1560                            const ValueEnumerator &VE,
1561                            BitstreamWriter &Stream, bool isGlobal) {
1562   if (FirstVal == LastVal) return;
1563 
1564   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
1565 
1566   unsigned AggregateAbbrev = 0;
1567   unsigned String8Abbrev = 0;
1568   unsigned CString7Abbrev = 0;
1569   unsigned CString6Abbrev = 0;
1570   // If this is a constant pool for the module, emit module-specific abbrevs.
1571   if (isGlobal) {
1572     // Abbrev for CST_CODE_AGGREGATE.
1573     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1574     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
1575     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1576     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
1577     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
1578 
1579     // Abbrev for CST_CODE_STRING.
1580     Abbv = new BitCodeAbbrev();
1581     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
1582     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1583     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1584     String8Abbrev = Stream.EmitAbbrev(Abbv);
1585     // Abbrev for CST_CODE_CSTRING.
1586     Abbv = new BitCodeAbbrev();
1587     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1588     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1589     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1590     CString7Abbrev = Stream.EmitAbbrev(Abbv);
1591     // Abbrev for CST_CODE_CSTRING.
1592     Abbv = new BitCodeAbbrev();
1593     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1594     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1595     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1596     CString6Abbrev = Stream.EmitAbbrev(Abbv);
1597   }
1598 
1599   SmallVector<uint64_t, 64> Record;
1600 
1601   const ValueEnumerator::ValueList &Vals = VE.getValues();
1602   Type *LastTy = nullptr;
1603   for (unsigned i = FirstVal; i != LastVal; ++i) {
1604     const Value *V = Vals[i].first;
1605     // If we need to switch types, do so now.
1606     if (V->getType() != LastTy) {
1607       LastTy = V->getType();
1608       Record.push_back(VE.getTypeID(LastTy));
1609       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
1610                         CONSTANTS_SETTYPE_ABBREV);
1611       Record.clear();
1612     }
1613 
1614     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
1615       Record.push_back(unsigned(IA->hasSideEffects()) |
1616                        unsigned(IA->isAlignStack()) << 1 |
1617                        unsigned(IA->getDialect()&1) << 2);
1618 
1619       // Add the asm string.
1620       const std::string &AsmStr = IA->getAsmString();
1621       Record.push_back(AsmStr.size());
1622       Record.append(AsmStr.begin(), AsmStr.end());
1623 
1624       // Add the constraint string.
1625       const std::string &ConstraintStr = IA->getConstraintString();
1626       Record.push_back(ConstraintStr.size());
1627       Record.append(ConstraintStr.begin(), ConstraintStr.end());
1628       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
1629       Record.clear();
1630       continue;
1631     }
1632     const Constant *C = cast<Constant>(V);
1633     unsigned Code = -1U;
1634     unsigned AbbrevToUse = 0;
1635     if (C->isNullValue()) {
1636       Code = bitc::CST_CODE_NULL;
1637     } else if (isa<UndefValue>(C)) {
1638       Code = bitc::CST_CODE_UNDEF;
1639     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
1640       if (IV->getBitWidth() <= 64) {
1641         uint64_t V = IV->getSExtValue();
1642         emitSignedInt64(Record, V);
1643         Code = bitc::CST_CODE_INTEGER;
1644         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
1645       } else {                             // Wide integers, > 64 bits in size.
1646         // We have an arbitrary precision integer value to write whose
1647         // bit width is > 64. However, in canonical unsigned integer
1648         // format it is likely that the high bits are going to be zero.
1649         // So, we only write the number of active words.
1650         unsigned NWords = IV->getValue().getActiveWords();
1651         const uint64_t *RawWords = IV->getValue().getRawData();
1652         for (unsigned i = 0; i != NWords; ++i) {
1653           emitSignedInt64(Record, RawWords[i]);
1654         }
1655         Code = bitc::CST_CODE_WIDE_INTEGER;
1656       }
1657     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
1658       Code = bitc::CST_CODE_FLOAT;
1659       Type *Ty = CFP->getType();
1660       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
1661         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
1662       } else if (Ty->isX86_FP80Ty()) {
1663         // api needed to prevent premature destruction
1664         // bits are not in the same order as a normal i80 APInt, compensate.
1665         APInt api = CFP->getValueAPF().bitcastToAPInt();
1666         const uint64_t *p = api.getRawData();
1667         Record.push_back((p[1] << 48) | (p[0] >> 16));
1668         Record.push_back(p[0] & 0xffffLL);
1669       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
1670         APInt api = CFP->getValueAPF().bitcastToAPInt();
1671         const uint64_t *p = api.getRawData();
1672         Record.push_back(p[0]);
1673         Record.push_back(p[1]);
1674       } else {
1675         assert (0 && "Unknown FP type!");
1676       }
1677     } else if (isa<ConstantDataSequential>(C) &&
1678                cast<ConstantDataSequential>(C)->isString()) {
1679       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
1680       // Emit constant strings specially.
1681       unsigned NumElts = Str->getNumElements();
1682       // If this is a null-terminated string, use the denser CSTRING encoding.
1683       if (Str->isCString()) {
1684         Code = bitc::CST_CODE_CSTRING;
1685         --NumElts;  // Don't encode the null, which isn't allowed by char6.
1686       } else {
1687         Code = bitc::CST_CODE_STRING;
1688         AbbrevToUse = String8Abbrev;
1689       }
1690       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
1691       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
1692       for (unsigned i = 0; i != NumElts; ++i) {
1693         unsigned char V = Str->getElementAsInteger(i);
1694         Record.push_back(V);
1695         isCStr7 &= (V & 128) == 0;
1696         if (isCStrChar6)
1697           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
1698       }
1699 
1700       if (isCStrChar6)
1701         AbbrevToUse = CString6Abbrev;
1702       else if (isCStr7)
1703         AbbrevToUse = CString7Abbrev;
1704     } else if (const ConstantDataSequential *CDS =
1705                   dyn_cast<ConstantDataSequential>(C)) {
1706       Code = bitc::CST_CODE_DATA;
1707       Type *EltTy = CDS->getType()->getElementType();
1708       if (isa<IntegerType>(EltTy)) {
1709         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
1710           Record.push_back(CDS->getElementAsInteger(i));
1711       } else {
1712         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
1713           Record.push_back(
1714               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
1715       }
1716     } else if (isa<ConstantAggregate>(C)) {
1717       Code = bitc::CST_CODE_AGGREGATE;
1718       for (const Value *Op : C->operands())
1719         Record.push_back(VE.getValueID(Op));
1720       AbbrevToUse = AggregateAbbrev;
1721     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
1722       switch (CE->getOpcode()) {
1723       default:
1724         if (Instruction::isCast(CE->getOpcode())) {
1725           Code = bitc::CST_CODE_CE_CAST;
1726           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
1727           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1728           Record.push_back(VE.getValueID(C->getOperand(0)));
1729           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
1730         } else {
1731           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
1732           Code = bitc::CST_CODE_CE_BINOP;
1733           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
1734           Record.push_back(VE.getValueID(C->getOperand(0)));
1735           Record.push_back(VE.getValueID(C->getOperand(1)));
1736           uint64_t Flags = GetOptimizationFlags(CE);
1737           if (Flags != 0)
1738             Record.push_back(Flags);
1739         }
1740         break;
1741       case Instruction::GetElementPtr: {
1742         Code = bitc::CST_CODE_CE_GEP;
1743         const auto *GO = cast<GEPOperator>(C);
1744         if (GO->isInBounds())
1745           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
1746         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
1747         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
1748           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
1749           Record.push_back(VE.getValueID(C->getOperand(i)));
1750         }
1751         break;
1752       }
1753       case Instruction::Select:
1754         Code = bitc::CST_CODE_CE_SELECT;
1755         Record.push_back(VE.getValueID(C->getOperand(0)));
1756         Record.push_back(VE.getValueID(C->getOperand(1)));
1757         Record.push_back(VE.getValueID(C->getOperand(2)));
1758         break;
1759       case Instruction::ExtractElement:
1760         Code = bitc::CST_CODE_CE_EXTRACTELT;
1761         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1762         Record.push_back(VE.getValueID(C->getOperand(0)));
1763         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
1764         Record.push_back(VE.getValueID(C->getOperand(1)));
1765         break;
1766       case Instruction::InsertElement:
1767         Code = bitc::CST_CODE_CE_INSERTELT;
1768         Record.push_back(VE.getValueID(C->getOperand(0)));
1769         Record.push_back(VE.getValueID(C->getOperand(1)));
1770         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
1771         Record.push_back(VE.getValueID(C->getOperand(2)));
1772         break;
1773       case Instruction::ShuffleVector:
1774         // If the return type and argument types are the same, this is a
1775         // standard shufflevector instruction.  If the types are different,
1776         // then the shuffle is widening or truncating the input vectors, and
1777         // the argument type must also be encoded.
1778         if (C->getType() == C->getOperand(0)->getType()) {
1779           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
1780         } else {
1781           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
1782           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1783         }
1784         Record.push_back(VE.getValueID(C->getOperand(0)));
1785         Record.push_back(VE.getValueID(C->getOperand(1)));
1786         Record.push_back(VE.getValueID(C->getOperand(2)));
1787         break;
1788       case Instruction::ICmp:
1789       case Instruction::FCmp:
1790         Code = bitc::CST_CODE_CE_CMP;
1791         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1792         Record.push_back(VE.getValueID(C->getOperand(0)));
1793         Record.push_back(VE.getValueID(C->getOperand(1)));
1794         Record.push_back(CE->getPredicate());
1795         break;
1796       }
1797     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
1798       Code = bitc::CST_CODE_BLOCKADDRESS;
1799       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
1800       Record.push_back(VE.getValueID(BA->getFunction()));
1801       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
1802     } else {
1803 #ifndef NDEBUG
1804       C->dump();
1805 #endif
1806       llvm_unreachable("Unknown constant!");
1807     }
1808     Stream.EmitRecord(Code, Record, AbbrevToUse);
1809     Record.clear();
1810   }
1811 
1812   Stream.ExitBlock();
1813 }
1814 
1815 static void WriteModuleConstants(const ValueEnumerator &VE,
1816                                  BitstreamWriter &Stream) {
1817   const ValueEnumerator::ValueList &Vals = VE.getValues();
1818 
1819   // Find the first constant to emit, which is the first non-globalvalue value.
1820   // We know globalvalues have been emitted by WriteModuleInfo.
1821   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
1822     if (!isa<GlobalValue>(Vals[i].first)) {
1823       WriteConstants(i, Vals.size(), VE, Stream, true);
1824       return;
1825     }
1826   }
1827 }
1828 
1829 /// PushValueAndType - The file has to encode both the value and type id for
1830 /// many values, because we need to know what type to create for forward
1831 /// references.  However, most operands are not forward references, so this type
1832 /// field is not needed.
1833 ///
1834 /// This function adds V's value ID to Vals.  If the value ID is higher than the
1835 /// instruction ID, then it is a forward reference, and it also includes the
1836 /// type ID.  The value ID that is written is encoded relative to the InstID.
1837 static bool PushValueAndType(const Value *V, unsigned InstID,
1838                              SmallVectorImpl<unsigned> &Vals,
1839                              ValueEnumerator &VE) {
1840   unsigned ValID = VE.getValueID(V);
1841   // Make encoding relative to the InstID.
1842   Vals.push_back(InstID - ValID);
1843   if (ValID >= InstID) {
1844     Vals.push_back(VE.getTypeID(V->getType()));
1845     return true;
1846   }
1847   return false;
1848 }
1849 
1850 static void WriteOperandBundles(BitstreamWriter &Stream, ImmutableCallSite CS,
1851                                 unsigned InstID, ValueEnumerator &VE) {
1852   SmallVector<unsigned, 64> Record;
1853   LLVMContext &C = CS.getInstruction()->getContext();
1854 
1855   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
1856     const auto &Bundle = CS.getOperandBundleAt(i);
1857     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
1858 
1859     for (auto &Input : Bundle.Inputs)
1860       PushValueAndType(Input, InstID, Record, VE);
1861 
1862     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
1863     Record.clear();
1864   }
1865 }
1866 
1867 /// pushValue - Like PushValueAndType, but where the type of the value is
1868 /// omitted (perhaps it was already encoded in an earlier operand).
1869 static void pushValue(const Value *V, unsigned InstID,
1870                       SmallVectorImpl<unsigned> &Vals,
1871                       ValueEnumerator &VE) {
1872   unsigned ValID = VE.getValueID(V);
1873   Vals.push_back(InstID - ValID);
1874 }
1875 
1876 static void pushValueSigned(const Value *V, unsigned InstID,
1877                             SmallVectorImpl<uint64_t> &Vals,
1878                             ValueEnumerator &VE) {
1879   unsigned ValID = VE.getValueID(V);
1880   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
1881   emitSignedInt64(Vals, diff);
1882 }
1883 
1884 /// WriteInstruction - Emit an instruction to the specified stream.
1885 static void WriteInstruction(const Instruction &I, unsigned InstID,
1886                              ValueEnumerator &VE, BitstreamWriter &Stream,
1887                              SmallVectorImpl<unsigned> &Vals) {
1888   unsigned Code = 0;
1889   unsigned AbbrevToUse = 0;
1890   VE.setInstructionID(&I);
1891   switch (I.getOpcode()) {
1892   default:
1893     if (Instruction::isCast(I.getOpcode())) {
1894       Code = bitc::FUNC_CODE_INST_CAST;
1895       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1896         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
1897       Vals.push_back(VE.getTypeID(I.getType()));
1898       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
1899     } else {
1900       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
1901       Code = bitc::FUNC_CODE_INST_BINOP;
1902       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1903         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
1904       pushValue(I.getOperand(1), InstID, Vals, VE);
1905       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
1906       uint64_t Flags = GetOptimizationFlags(&I);
1907       if (Flags != 0) {
1908         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
1909           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
1910         Vals.push_back(Flags);
1911       }
1912     }
1913     break;
1914 
1915   case Instruction::GetElementPtr: {
1916     Code = bitc::FUNC_CODE_INST_GEP;
1917     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
1918     auto &GEPInst = cast<GetElementPtrInst>(I);
1919     Vals.push_back(GEPInst.isInBounds());
1920     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
1921     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1922       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1923     break;
1924   }
1925   case Instruction::ExtractValue: {
1926     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
1927     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1928     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
1929     Vals.append(EVI->idx_begin(), EVI->idx_end());
1930     break;
1931   }
1932   case Instruction::InsertValue: {
1933     Code = bitc::FUNC_CODE_INST_INSERTVAL;
1934     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1935     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1936     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
1937     Vals.append(IVI->idx_begin(), IVI->idx_end());
1938     break;
1939   }
1940   case Instruction::Select:
1941     Code = bitc::FUNC_CODE_INST_VSELECT;
1942     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1943     pushValue(I.getOperand(2), InstID, Vals, VE);
1944     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1945     break;
1946   case Instruction::ExtractElement:
1947     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
1948     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1949     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1950     break;
1951   case Instruction::InsertElement:
1952     Code = bitc::FUNC_CODE_INST_INSERTELT;
1953     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1954     pushValue(I.getOperand(1), InstID, Vals, VE);
1955     PushValueAndType(I.getOperand(2), InstID, Vals, VE);
1956     break;
1957   case Instruction::ShuffleVector:
1958     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1959     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1960     pushValue(I.getOperand(1), InstID, Vals, VE);
1961     pushValue(I.getOperand(2), InstID, Vals, VE);
1962     break;
1963   case Instruction::ICmp:
1964   case Instruction::FCmp: {
1965     // compare returning Int1Ty or vector of Int1Ty
1966     Code = bitc::FUNC_CODE_INST_CMP2;
1967     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1968     pushValue(I.getOperand(1), InstID, Vals, VE);
1969     Vals.push_back(cast<CmpInst>(I).getPredicate());
1970     uint64_t Flags = GetOptimizationFlags(&I);
1971     if (Flags != 0)
1972       Vals.push_back(Flags);
1973     break;
1974   }
1975 
1976   case Instruction::Ret:
1977     {
1978       Code = bitc::FUNC_CODE_INST_RET;
1979       unsigned NumOperands = I.getNumOperands();
1980       if (NumOperands == 0)
1981         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1982       else if (NumOperands == 1) {
1983         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1984           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1985       } else {
1986         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1987           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1988       }
1989     }
1990     break;
1991   case Instruction::Br:
1992     {
1993       Code = bitc::FUNC_CODE_INST_BR;
1994       const BranchInst &II = cast<BranchInst>(I);
1995       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1996       if (II.isConditional()) {
1997         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1998         pushValue(II.getCondition(), InstID, Vals, VE);
1999       }
2000     }
2001     break;
2002   case Instruction::Switch:
2003     {
2004       Code = bitc::FUNC_CODE_INST_SWITCH;
2005       const SwitchInst &SI = cast<SwitchInst>(I);
2006       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2007       pushValue(SI.getCondition(), InstID, Vals, VE);
2008       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2009       for (SwitchInst::ConstCaseIt Case : SI.cases()) {
2010         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2011         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2012       }
2013     }
2014     break;
2015   case Instruction::IndirectBr:
2016     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2017     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2018     // Encode the address operand as relative, but not the basic blocks.
2019     pushValue(I.getOperand(0), InstID, Vals, VE);
2020     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2021       Vals.push_back(VE.getValueID(I.getOperand(i)));
2022     break;
2023 
2024   case Instruction::Invoke: {
2025     const InvokeInst *II = cast<InvokeInst>(&I);
2026     const Value *Callee = II->getCalledValue();
2027     FunctionType *FTy = II->getFunctionType();
2028 
2029     if (II->hasOperandBundles())
2030       WriteOperandBundles(Stream, II, InstID, VE);
2031 
2032     Code = bitc::FUNC_CODE_INST_INVOKE;
2033 
2034     Vals.push_back(VE.getAttributeID(II->getAttributes()));
2035     Vals.push_back(II->getCallingConv() | 1 << 13);
2036     Vals.push_back(VE.getValueID(II->getNormalDest()));
2037     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2038     Vals.push_back(VE.getTypeID(FTy));
2039     PushValueAndType(Callee, InstID, Vals, VE);
2040 
2041     // Emit value #'s for the fixed parameters.
2042     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2043       pushValue(I.getOperand(i), InstID, Vals, VE);  // fixed param.
2044 
2045     // Emit type/value pairs for varargs params.
2046     if (FTy->isVarArg()) {
2047       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
2048            i != e; ++i)
2049         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
2050     }
2051     break;
2052   }
2053   case Instruction::Resume:
2054     Code = bitc::FUNC_CODE_INST_RESUME;
2055     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
2056     break;
2057   case Instruction::CleanupRet: {
2058     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2059     const auto &CRI = cast<CleanupReturnInst>(I);
2060     pushValue(CRI.getCleanupPad(), InstID, Vals, VE);
2061     if (CRI.hasUnwindDest())
2062       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2063     break;
2064   }
2065   case Instruction::CatchRet: {
2066     Code = bitc::FUNC_CODE_INST_CATCHRET;
2067     const auto &CRI = cast<CatchReturnInst>(I);
2068     pushValue(CRI.getCatchPad(), InstID, Vals, VE);
2069     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2070     break;
2071   }
2072   case Instruction::CleanupPad:
2073   case Instruction::CatchPad: {
2074     const auto &FuncletPad = cast<FuncletPadInst>(I);
2075     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2076                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2077     pushValue(FuncletPad.getParentPad(), InstID, Vals, VE);
2078 
2079     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2080     Vals.push_back(NumArgOperands);
2081     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2082       PushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals, VE);
2083     break;
2084   }
2085   case Instruction::CatchSwitch: {
2086     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2087     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2088 
2089     pushValue(CatchSwitch.getParentPad(), InstID, Vals, VE);
2090 
2091     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2092     Vals.push_back(NumHandlers);
2093     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2094       Vals.push_back(VE.getValueID(CatchPadBB));
2095 
2096     if (CatchSwitch.hasUnwindDest())
2097       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
2098     break;
2099   }
2100   case Instruction::Unreachable:
2101     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
2102     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
2103     break;
2104 
2105   case Instruction::PHI: {
2106     const PHINode &PN = cast<PHINode>(I);
2107     Code = bitc::FUNC_CODE_INST_PHI;
2108     // With the newer instruction encoding, forward references could give
2109     // negative valued IDs.  This is most common for PHIs, so we use
2110     // signed VBRs.
2111     SmallVector<uint64_t, 128> Vals64;
2112     Vals64.push_back(VE.getTypeID(PN.getType()));
2113     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
2114       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64, VE);
2115       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
2116     }
2117     // Emit a Vals64 vector and exit.
2118     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
2119     Vals64.clear();
2120     return;
2121   }
2122 
2123   case Instruction::LandingPad: {
2124     const LandingPadInst &LP = cast<LandingPadInst>(I);
2125     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
2126     Vals.push_back(VE.getTypeID(LP.getType()));
2127     Vals.push_back(LP.isCleanup());
2128     Vals.push_back(LP.getNumClauses());
2129     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
2130       if (LP.isCatch(I))
2131         Vals.push_back(LandingPadInst::Catch);
2132       else
2133         Vals.push_back(LandingPadInst::Filter);
2134       PushValueAndType(LP.getClause(I), InstID, Vals, VE);
2135     }
2136     break;
2137   }
2138 
2139   case Instruction::Alloca: {
2140     Code = bitc::FUNC_CODE_INST_ALLOCA;
2141     const AllocaInst &AI = cast<AllocaInst>(I);
2142     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
2143     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2144     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
2145     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
2146     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
2147            "not enough bits for maximum alignment");
2148     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
2149     AlignRecord |= AI.isUsedWithInAlloca() << 5;
2150     AlignRecord |= 1 << 6;
2151     AlignRecord |= AI.isSwiftError() << 7;
2152     Vals.push_back(AlignRecord);
2153     break;
2154   }
2155 
2156   case Instruction::Load:
2157     if (cast<LoadInst>(I).isAtomic()) {
2158       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
2159       PushValueAndType(I.getOperand(0), InstID, Vals, VE);
2160     } else {
2161       Code = bitc::FUNC_CODE_INST_LOAD;
2162       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
2163         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
2164     }
2165     Vals.push_back(VE.getTypeID(I.getType()));
2166     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
2167     Vals.push_back(cast<LoadInst>(I).isVolatile());
2168     if (cast<LoadInst>(I).isAtomic()) {
2169       Vals.push_back(GetEncodedOrdering(cast<LoadInst>(I).getOrdering()));
2170       Vals.push_back(GetEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
2171     }
2172     break;
2173   case Instruction::Store:
2174     if (cast<StoreInst>(I).isAtomic())
2175       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
2176     else
2177       Code = bitc::FUNC_CODE_INST_STORE;
2178     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
2179     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // valty + val
2180     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
2181     Vals.push_back(cast<StoreInst>(I).isVolatile());
2182     if (cast<StoreInst>(I).isAtomic()) {
2183       Vals.push_back(GetEncodedOrdering(cast<StoreInst>(I).getOrdering()));
2184       Vals.push_back(GetEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
2185     }
2186     break;
2187   case Instruction::AtomicCmpXchg:
2188     Code = bitc::FUNC_CODE_INST_CMPXCHG;
2189     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
2190     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // cmp.
2191     pushValue(I.getOperand(2), InstID, Vals, VE);         // newval.
2192     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
2193     Vals.push_back(GetEncodedOrdering(
2194                      cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
2195     Vals.push_back(GetEncodedSynchScope(
2196                      cast<AtomicCmpXchgInst>(I).getSynchScope()));
2197     Vals.push_back(GetEncodedOrdering(
2198                      cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
2199     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
2200     break;
2201   case Instruction::AtomicRMW:
2202     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
2203     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
2204     pushValue(I.getOperand(1), InstID, Vals, VE);         // val.
2205     Vals.push_back(GetEncodedRMWOperation(
2206                      cast<AtomicRMWInst>(I).getOperation()));
2207     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
2208     Vals.push_back(GetEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
2209     Vals.push_back(GetEncodedSynchScope(
2210                      cast<AtomicRMWInst>(I).getSynchScope()));
2211     break;
2212   case Instruction::Fence:
2213     Code = bitc::FUNC_CODE_INST_FENCE;
2214     Vals.push_back(GetEncodedOrdering(cast<FenceInst>(I).getOrdering()));
2215     Vals.push_back(GetEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
2216     break;
2217   case Instruction::Call: {
2218     const CallInst &CI = cast<CallInst>(I);
2219     FunctionType *FTy = CI.getFunctionType();
2220 
2221     if (CI.hasOperandBundles())
2222       WriteOperandBundles(Stream, &CI, InstID, VE);
2223 
2224     Code = bitc::FUNC_CODE_INST_CALL;
2225 
2226     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
2227 
2228     unsigned Flags = GetOptimizationFlags(&I);
2229     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
2230                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
2231                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
2232                    1 << bitc::CALL_EXPLICIT_TYPE |
2233                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
2234                    unsigned(Flags != 0) << bitc::CALL_FMF);
2235     if (Flags != 0)
2236       Vals.push_back(Flags);
2237 
2238     Vals.push_back(VE.getTypeID(FTy));
2239     PushValueAndType(CI.getCalledValue(), InstID, Vals, VE);  // Callee
2240 
2241     // Emit value #'s for the fixed parameters.
2242     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
2243       // Check for labels (can happen with asm labels).
2244       if (FTy->getParamType(i)->isLabelTy())
2245         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
2246       else
2247         pushValue(CI.getArgOperand(i), InstID, Vals, VE);  // fixed param.
2248     }
2249 
2250     // Emit type/value pairs for varargs params.
2251     if (FTy->isVarArg()) {
2252       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
2253            i != e; ++i)
2254         PushValueAndType(CI.getArgOperand(i), InstID, Vals, VE);  // varargs
2255     }
2256     break;
2257   }
2258   case Instruction::VAArg:
2259     Code = bitc::FUNC_CODE_INST_VAARG;
2260     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
2261     pushValue(I.getOperand(0), InstID, Vals, VE); // valist.
2262     Vals.push_back(VE.getTypeID(I.getType())); // restype.
2263     break;
2264   }
2265 
2266   Stream.EmitRecord(Code, Vals, AbbrevToUse);
2267   Vals.clear();
2268 }
2269 
2270 /// Emit names for globals/functions etc. The VSTOffsetPlaceholder,
2271 /// BitcodeStartBit and ModuleSummaryIndex are only passed for the module-level
2272 /// VST, where we are including a function bitcode index and need to
2273 /// backpatch the VST forward declaration record.
2274 static void WriteValueSymbolTable(
2275     const ValueSymbolTable &VST, const ValueEnumerator &VE,
2276     BitstreamWriter &Stream, uint64_t VSTOffsetPlaceholder = 0,
2277     uint64_t BitcodeStartBit = 0,
2278     DenseMap<const Function *, uint64_t> *FunctionToBitcodeIndex = nullptr) {
2279   if (VST.empty()) {
2280     // WriteValueSymbolTableForwardDecl should have returned early as
2281     // well. Ensure this handling remains in sync by asserting that
2282     // the placeholder offset is not set.
2283     assert(VSTOffsetPlaceholder == 0);
2284     return;
2285   }
2286 
2287   if (VSTOffsetPlaceholder > 0) {
2288     // Get the offset of the VST we are writing, and backpatch it into
2289     // the VST forward declaration record.
2290     uint64_t VSTOffset = Stream.GetCurrentBitNo();
2291     // The BitcodeStartBit was the stream offset of the actual bitcode
2292     // (e.g. excluding any initial darwin header).
2293     VSTOffset -= BitcodeStartBit;
2294     assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
2295     Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32);
2296   }
2297 
2298   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
2299 
2300   // For the module-level VST, add abbrev Ids for the VST_CODE_FNENTRY
2301   // records, which are not used in the per-function VSTs.
2302   unsigned FnEntry8BitAbbrev;
2303   unsigned FnEntry7BitAbbrev;
2304   unsigned FnEntry6BitAbbrev;
2305   if (VSTOffsetPlaceholder > 0) {
2306     // 8-bit fixed-width VST_CODE_FNENTRY function strings.
2307     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2308     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2309     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2310     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2311     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2312     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2313     FnEntry8BitAbbrev = Stream.EmitAbbrev(Abbv);
2314 
2315     // 7-bit fixed width VST_CODE_FNENTRY function strings.
2316     Abbv = new BitCodeAbbrev();
2317     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2318     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2319     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2320     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2321     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2322     FnEntry7BitAbbrev = Stream.EmitAbbrev(Abbv);
2323 
2324     // 6-bit char6 VST_CODE_FNENTRY function strings.
2325     Abbv = new BitCodeAbbrev();
2326     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2327     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2328     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2329     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2330     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2331     FnEntry6BitAbbrev = Stream.EmitAbbrev(Abbv);
2332   }
2333 
2334   // FIXME: Set up the abbrev, we know how many values there are!
2335   // FIXME: We know if the type names can use 7-bit ascii.
2336   SmallVector<unsigned, 64> NameVals;
2337 
2338   for (const ValueName &Name : VST) {
2339     // Figure out the encoding to use for the name.
2340     StringEncoding Bits =
2341         getStringEncoding(Name.getKeyData(), Name.getKeyLength());
2342 
2343     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
2344     NameVals.push_back(VE.getValueID(Name.getValue()));
2345 
2346     Function *F = dyn_cast<Function>(Name.getValue());
2347     if (!F) {
2348       // If value is an alias, need to get the aliased base object to
2349       // see if it is a function.
2350       auto *GA = dyn_cast<GlobalAlias>(Name.getValue());
2351       if (GA && GA->getBaseObject())
2352         F = dyn_cast<Function>(GA->getBaseObject());
2353     }
2354 
2355     // VST_CODE_ENTRY:   [valueid, namechar x N]
2356     // VST_CODE_FNENTRY: [valueid, funcoffset, namechar x N]
2357     // VST_CODE_BBENTRY: [bbid, namechar x N]
2358     unsigned Code;
2359     if (isa<BasicBlock>(Name.getValue())) {
2360       Code = bitc::VST_CODE_BBENTRY;
2361       if (Bits == SE_Char6)
2362         AbbrevToUse = VST_BBENTRY_6_ABBREV;
2363     } else if (F && !F->isDeclaration()) {
2364       // Must be the module-level VST, where we pass in the Index and
2365       // have a VSTOffsetPlaceholder. The function-level VST should not
2366       // contain any Function symbols.
2367       assert(FunctionToBitcodeIndex);
2368       assert(VSTOffsetPlaceholder > 0);
2369 
2370       // Save the word offset of the function (from the start of the
2371       // actual bitcode written to the stream).
2372       uint64_t BitcodeIndex = (*FunctionToBitcodeIndex)[F] - BitcodeStartBit;
2373       assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
2374       NameVals.push_back(BitcodeIndex / 32);
2375 
2376       Code = bitc::VST_CODE_FNENTRY;
2377       AbbrevToUse = FnEntry8BitAbbrev;
2378       if (Bits == SE_Char6)
2379         AbbrevToUse = FnEntry6BitAbbrev;
2380       else if (Bits == SE_Fixed7)
2381         AbbrevToUse = FnEntry7BitAbbrev;
2382     } else {
2383       Code = bitc::VST_CODE_ENTRY;
2384       if (Bits == SE_Char6)
2385         AbbrevToUse = VST_ENTRY_6_ABBREV;
2386       else if (Bits == SE_Fixed7)
2387         AbbrevToUse = VST_ENTRY_7_ABBREV;
2388     }
2389 
2390     for (const auto P : Name.getKey())
2391       NameVals.push_back((unsigned char)P);
2392 
2393     // Emit the finished record.
2394     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
2395     NameVals.clear();
2396   }
2397   Stream.ExitBlock();
2398 }
2399 
2400 /// Emit function names and summary offsets for the combined index
2401 /// used by ThinLTO.
2402 static void WriteCombinedValueSymbolTable(
2403     const ModuleSummaryIndex &Index, BitstreamWriter &Stream,
2404     std::map<GlobalValue::GUID, unsigned> &GUIDToValueIdMap,
2405     uint64_t VSTOffsetPlaceholder) {
2406   assert(VSTOffsetPlaceholder > 0 && "Expected non-zero VSTOffsetPlaceholder");
2407   // Get the offset of the VST we are writing, and backpatch it into
2408   // the VST forward declaration record.
2409   uint64_t VSTOffset = Stream.GetCurrentBitNo();
2410   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
2411   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32);
2412 
2413   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
2414 
2415   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2416   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_COMBINED_GVDEFENTRY));
2417   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
2418   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // sumoffset
2419   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // guid
2420   unsigned DefEntryAbbrev = Stream.EmitAbbrev(Abbv);
2421 
2422   Abbv = new BitCodeAbbrev();
2423   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_COMBINED_ENTRY));
2424   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
2425   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // refguid
2426   unsigned EntryAbbrev = Stream.EmitAbbrev(Abbv);
2427 
2428   SmallVector<uint64_t, 64> NameVals;
2429 
2430   for (const auto &FII : Index) {
2431     GlobalValue::GUID FuncGUID = FII.first;
2432     const auto &VMI = GUIDToValueIdMap.find(FuncGUID);
2433     assert(VMI != GUIDToValueIdMap.end());
2434 
2435     for (const auto &FI : FII.second) {
2436       // VST_CODE_COMBINED_GVDEFENTRY: [valueid, sumoffset, guid]
2437       NameVals.push_back(VMI->second);
2438       NameVals.push_back(FI->bitcodeIndex());
2439       NameVals.push_back(FuncGUID);
2440 
2441       // Emit the finished record.
2442       Stream.EmitRecord(bitc::VST_CODE_COMBINED_GVDEFENTRY, NameVals,
2443                         DefEntryAbbrev);
2444       NameVals.clear();
2445     }
2446     GUIDToValueIdMap.erase(VMI);
2447   }
2448   for (const auto &GVI : GUIDToValueIdMap) {
2449     // VST_CODE_COMBINED_ENTRY: [valueid, refguid]
2450     NameVals.push_back(GVI.second);
2451     NameVals.push_back(GVI.first);
2452 
2453     // Emit the finished record.
2454     Stream.EmitRecord(bitc::VST_CODE_COMBINED_ENTRY, NameVals, EntryAbbrev);
2455     NameVals.clear();
2456   }
2457   Stream.ExitBlock();
2458 }
2459 
2460 static void WriteUseList(ValueEnumerator &VE, UseListOrder &&Order,
2461                          BitstreamWriter &Stream) {
2462   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
2463   unsigned Code;
2464   if (isa<BasicBlock>(Order.V))
2465     Code = bitc::USELIST_CODE_BB;
2466   else
2467     Code = bitc::USELIST_CODE_DEFAULT;
2468 
2469   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
2470   Record.push_back(VE.getValueID(Order.V));
2471   Stream.EmitRecord(Code, Record);
2472 }
2473 
2474 static void WriteUseListBlock(const Function *F, ValueEnumerator &VE,
2475                               BitstreamWriter &Stream) {
2476   assert(VE.shouldPreserveUseListOrder() &&
2477          "Expected to be preserving use-list order");
2478 
2479   auto hasMore = [&]() {
2480     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
2481   };
2482   if (!hasMore())
2483     // Nothing to do.
2484     return;
2485 
2486   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
2487   while (hasMore()) {
2488     WriteUseList(VE, std::move(VE.UseListOrders.back()), Stream);
2489     VE.UseListOrders.pop_back();
2490   }
2491   Stream.ExitBlock();
2492 }
2493 
2494 /// Emit a function body to the module stream.
2495 static void
2496 WriteFunction(const Function &F, const Module *M, ValueEnumerator &VE,
2497               BitstreamWriter &Stream,
2498               DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
2499   // Save the bitcode index of the start of this function block for recording
2500   // in the VST.
2501   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
2502 
2503   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
2504   VE.incorporateFunction(F);
2505 
2506   SmallVector<unsigned, 64> Vals;
2507 
2508   // Emit the number of basic blocks, so the reader can create them ahead of
2509   // time.
2510   Vals.push_back(VE.getBasicBlocks().size());
2511   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
2512   Vals.clear();
2513 
2514   // If there are function-local constants, emit them now.
2515   unsigned CstStart, CstEnd;
2516   VE.getFunctionConstantRange(CstStart, CstEnd);
2517   WriteConstants(CstStart, CstEnd, VE, Stream, false);
2518 
2519   // If there is function-local metadata, emit it now.
2520   writeFunctionMetadata(F, VE, Stream);
2521 
2522   // Keep a running idea of what the instruction ID is.
2523   unsigned InstID = CstEnd;
2524 
2525   bool NeedsMetadataAttachment = F.hasMetadata();
2526 
2527   DILocation *LastDL = nullptr;
2528   // Finally, emit all the instructions, in order.
2529   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
2530     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
2531          I != E; ++I) {
2532       WriteInstruction(*I, InstID, VE, Stream, Vals);
2533 
2534       if (!I->getType()->isVoidTy())
2535         ++InstID;
2536 
2537       // If the instruction has metadata, write a metadata attachment later.
2538       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
2539 
2540       // If the instruction has a debug location, emit it.
2541       DILocation *DL = I->getDebugLoc();
2542       if (!DL)
2543         continue;
2544 
2545       if (DL == LastDL) {
2546         // Just repeat the same debug loc as last time.
2547         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
2548         continue;
2549       }
2550 
2551       Vals.push_back(DL->getLine());
2552       Vals.push_back(DL->getColumn());
2553       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
2554       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
2555       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
2556       Vals.clear();
2557 
2558       LastDL = DL;
2559     }
2560 
2561   // Emit names for all the instructions etc.
2562   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
2563 
2564   if (NeedsMetadataAttachment)
2565     WriteMetadataAttachment(F, VE, Stream);
2566   if (VE.shouldPreserveUseListOrder())
2567     WriteUseListBlock(&F, VE, Stream);
2568   VE.purgeFunction();
2569   Stream.ExitBlock();
2570 }
2571 
2572 // Emit blockinfo, which defines the standard abbreviations etc.
2573 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
2574   // We only want to emit block info records for blocks that have multiple
2575   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
2576   // Other blocks can define their abbrevs inline.
2577   Stream.EnterBlockInfoBlock(2);
2578 
2579   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
2580     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2581     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
2582     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2583     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2584     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2585     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2586                                    Abbv) != VST_ENTRY_8_ABBREV)
2587       llvm_unreachable("Unexpected abbrev ordering!");
2588   }
2589 
2590   { // 7-bit fixed width VST_CODE_ENTRY strings.
2591     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2592     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2593     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2594     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2595     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2596     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2597                                    Abbv) != VST_ENTRY_7_ABBREV)
2598       llvm_unreachable("Unexpected abbrev ordering!");
2599   }
2600   { // 6-bit char6 VST_CODE_ENTRY strings.
2601     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2602     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2603     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2604     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2605     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2606     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2607                                    Abbv) != VST_ENTRY_6_ABBREV)
2608       llvm_unreachable("Unexpected abbrev ordering!");
2609   }
2610   { // 6-bit char6 VST_CODE_BBENTRY strings.
2611     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2612     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
2613     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2614     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2615     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2616     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2617                                    Abbv) != VST_BBENTRY_6_ABBREV)
2618       llvm_unreachable("Unexpected abbrev ordering!");
2619   }
2620 
2621 
2622 
2623   { // SETTYPE abbrev for CONSTANTS_BLOCK.
2624     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2625     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
2626     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
2627                               VE.computeBitsRequiredForTypeIndicies()));
2628     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2629                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
2630       llvm_unreachable("Unexpected abbrev ordering!");
2631   }
2632 
2633   { // INTEGER abbrev for CONSTANTS_BLOCK.
2634     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2635     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
2636     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2637     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2638                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
2639       llvm_unreachable("Unexpected abbrev ordering!");
2640   }
2641 
2642   { // CE_CAST abbrev for CONSTANTS_BLOCK.
2643     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2644     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
2645     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
2646     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
2647                               VE.computeBitsRequiredForTypeIndicies()));
2648     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
2649 
2650     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2651                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
2652       llvm_unreachable("Unexpected abbrev ordering!");
2653   }
2654   { // NULL abbrev for CONSTANTS_BLOCK.
2655     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2656     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
2657     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2658                                    Abbv) != CONSTANTS_NULL_Abbrev)
2659       llvm_unreachable("Unexpected abbrev ordering!");
2660   }
2661 
2662   // FIXME: This should only use space for first class types!
2663 
2664   { // INST_LOAD abbrev for FUNCTION_BLOCK.
2665     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2666     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
2667     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
2668     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
2669                               VE.computeBitsRequiredForTypeIndicies()));
2670     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
2671     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
2672     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2673                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
2674       llvm_unreachable("Unexpected abbrev ordering!");
2675   }
2676   { // INST_BINOP abbrev for FUNCTION_BLOCK.
2677     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2678     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2679     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2680     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2681     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2682     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2683                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
2684       llvm_unreachable("Unexpected abbrev ordering!");
2685   }
2686   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
2687     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2688     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2689     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2690     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2691     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2692     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
2693     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2694                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
2695       llvm_unreachable("Unexpected abbrev ordering!");
2696   }
2697   { // INST_CAST abbrev for FUNCTION_BLOCK.
2698     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2699     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
2700     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
2701     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
2702                               VE.computeBitsRequiredForTypeIndicies()));
2703     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
2704     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2705                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
2706       llvm_unreachable("Unexpected abbrev ordering!");
2707   }
2708 
2709   { // INST_RET abbrev for FUNCTION_BLOCK.
2710     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2711     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2712     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2713                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
2714       llvm_unreachable("Unexpected abbrev ordering!");
2715   }
2716   { // INST_RET abbrev for FUNCTION_BLOCK.
2717     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2718     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2719     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
2720     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2721                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
2722       llvm_unreachable("Unexpected abbrev ordering!");
2723   }
2724   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
2725     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2726     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
2727     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2728                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
2729       llvm_unreachable("Unexpected abbrev ordering!");
2730   }
2731   {
2732     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2733     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
2734     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2735     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
2736                               Log2_32_Ceil(VE.getTypes().size() + 1)));
2737     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2738     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2739     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2740         FUNCTION_INST_GEP_ABBREV)
2741       llvm_unreachable("Unexpected abbrev ordering!");
2742   }
2743 
2744   Stream.ExitBlock();
2745 }
2746 
2747 /// Write the module path strings, currently only used when generating
2748 /// a combined index file.
2749 static void WriteModStrings(const ModuleSummaryIndex &I,
2750                             BitstreamWriter &Stream) {
2751   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
2752 
2753   // TODO: See which abbrev sizes we actually need to emit
2754 
2755   // 8-bit fixed-width MST_ENTRY strings.
2756   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2757   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
2758   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2759   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2760   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2761   unsigned Abbrev8Bit = Stream.EmitAbbrev(Abbv);
2762 
2763   // 7-bit fixed width MST_ENTRY strings.
2764   Abbv = new BitCodeAbbrev();
2765   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
2766   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2767   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2768   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2769   unsigned Abbrev7Bit = Stream.EmitAbbrev(Abbv);
2770 
2771   // 6-bit char6 MST_ENTRY strings.
2772   Abbv = new BitCodeAbbrev();
2773   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
2774   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2775   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2776   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2777   unsigned Abbrev6Bit = Stream.EmitAbbrev(Abbv);
2778 
2779   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
2780   Abbv = new BitCodeAbbrev();
2781   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
2782   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2783   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2784   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2785   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2786   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2787   unsigned AbbrevHash = Stream.EmitAbbrev(Abbv);
2788 
2789   SmallVector<unsigned, 64> Vals;
2790   for (const auto &MPSE : I.modulePaths()) {
2791     StringEncoding Bits =
2792         getStringEncoding(MPSE.getKey().data(), MPSE.getKey().size());
2793     unsigned AbbrevToUse = Abbrev8Bit;
2794     if (Bits == SE_Char6)
2795       AbbrevToUse = Abbrev6Bit;
2796     else if (Bits == SE_Fixed7)
2797       AbbrevToUse = Abbrev7Bit;
2798 
2799     Vals.push_back(MPSE.getValue().first);
2800 
2801     for (const auto P : MPSE.getKey())
2802       Vals.push_back((unsigned char)P);
2803 
2804     // Emit the finished record.
2805     Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
2806 
2807     Vals.clear();
2808     // Emit an optional hash for the module now
2809     auto &Hash = MPSE.getValue().second;
2810     bool AllZero = true; // Detect if the hash is empty, and do not generate it
2811     for (auto Val : Hash) {
2812       if (Val)
2813         AllZero = false;
2814       Vals.push_back(Val);
2815     }
2816     if (!AllZero) {
2817       // Emit the hash record.
2818       Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
2819     }
2820 
2821     Vals.clear();
2822   }
2823   Stream.ExitBlock();
2824 }
2825 
2826 // Helper to emit a single function summary record.
2827 static void WritePerModuleFunctionSummaryRecord(
2828     SmallVector<uint64_t, 64> &NameVals, GlobalValueInfo *Info,
2829     unsigned ValueID, const ValueEnumerator &VE, unsigned FSCallsAbbrev,
2830     unsigned FSCallsProfileAbbrev, BitstreamWriter &Stream, const Function &F) {
2831   NameVals.push_back(ValueID);
2832 
2833   FunctionSummary *FS = cast<FunctionSummary>(Info->summary());
2834   NameVals.push_back(getEncodedLinkage(FS->linkage()));
2835   NameVals.push_back(FS->instCount());
2836   NameVals.push_back(FS->refs().size());
2837 
2838   for (auto &RI : FS->refs())
2839     NameVals.push_back(VE.getValueID(RI.getValue()));
2840 
2841   bool HasProfileData = F.getEntryCount().hasValue();
2842   for (auto &ECI : FS->calls()) {
2843     NameVals.push_back(VE.getValueID(ECI.first.getValue()));
2844     assert(ECI.second.CallsiteCount > 0 && "Expected at least one callsite");
2845     NameVals.push_back(ECI.second.CallsiteCount);
2846     if (HasProfileData)
2847       NameVals.push_back(ECI.second.ProfileCount);
2848   }
2849 
2850   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
2851   unsigned Code =
2852       (HasProfileData ? bitc::FS_PERMODULE_PROFILE : bitc::FS_PERMODULE);
2853 
2854   // Emit the finished record.
2855   Stream.EmitRecord(Code, NameVals, FSAbbrev);
2856   NameVals.clear();
2857 }
2858 
2859 // Collect the global value references in the given variable's initializer,
2860 // and emit them in a summary record.
2861 static void WriteModuleLevelReferences(const GlobalVariable &V,
2862                                        const ModuleSummaryIndex &Index,
2863                                        const ValueEnumerator &VE,
2864                                        SmallVector<uint64_t, 64> &NameVals,
2865                                        unsigned FSModRefsAbbrev,
2866                                        BitstreamWriter &Stream) {
2867   // Only interested in recording variable defs in the summary.
2868   if (V.isDeclaration())
2869     return;
2870   NameVals.push_back(VE.getValueID(&V));
2871   NameVals.push_back(getEncodedLinkage(V.getLinkage()));
2872   auto *Info = Index.getGlobalValueInfo(V);
2873   GlobalVarSummary *VS = cast<GlobalVarSummary>(Info->summary());
2874   for (auto Ref : VS->refs())
2875     NameVals.push_back(VE.getValueID(Ref.getValue()));
2876   Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
2877                     FSModRefsAbbrev);
2878   NameVals.clear();
2879 }
2880 
2881 /// Emit the per-module summary section alongside the rest of
2882 /// the module's bitcode.
2883 static void WritePerModuleGlobalValueSummary(const Module *M,
2884                                              const ModuleSummaryIndex &Index,
2885                                              const ValueEnumerator &VE,
2886                                              BitstreamWriter &Stream) {
2887   if (M->empty())
2888     return;
2889 
2890   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
2891 
2892   // Abbrev for FS_PERMODULE.
2893   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2894   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
2895   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
2896   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // linkage
2897   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
2898   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
2899   // numrefs x valueid, n x (valueid, callsitecount)
2900   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2901   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2902   unsigned FSCallsAbbrev = Stream.EmitAbbrev(Abbv);
2903 
2904   // Abbrev for FS_PERMODULE_PROFILE.
2905   Abbv = new BitCodeAbbrev();
2906   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
2907   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
2908   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // linkage
2909   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
2910   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
2911   // numrefs x valueid, n x (valueid, callsitecount, profilecount)
2912   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2913   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2914   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(Abbv);
2915 
2916   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
2917   Abbv = new BitCodeAbbrev();
2918   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
2919   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
2920   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // linkage
2921   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
2922   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2923   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(Abbv);
2924 
2925   SmallVector<uint64_t, 64> NameVals;
2926   // Iterate over the list of functions instead of the Index to
2927   // ensure the ordering is stable.
2928   for (const Function &F : *M) {
2929     if (F.isDeclaration())
2930       continue;
2931     // Skip anonymous functions. We will emit a function summary for
2932     // any aliases below.
2933     if (!F.hasName())
2934       continue;
2935 
2936     auto *Info = Index.getGlobalValueInfo(F);
2937     WritePerModuleFunctionSummaryRecord(
2938         NameVals, Info,
2939         VE.getValueID(M->getValueSymbolTable().lookup(F.getName())), VE,
2940         FSCallsAbbrev, FSCallsProfileAbbrev, Stream, F);
2941   }
2942 
2943   // Capture references from GlobalVariable initializers, which are outside
2944   // of a function scope.
2945   for (const GlobalVariable &G : M->globals())
2946     WriteModuleLevelReferences(G, Index, VE, NameVals, FSModRefsAbbrev, Stream);
2947 
2948   Stream.ExitBlock();
2949 }
2950 
2951 /// Emit the combined summary section into the combined index file.
2952 static void WriteCombinedGlobalValueSummary(
2953     const ModuleSummaryIndex &Index, BitstreamWriter &Stream,
2954     std::map<GlobalValue::GUID, unsigned> &GUIDToValueIdMap,
2955     unsigned GlobalValueId) {
2956   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
2957 
2958   // Abbrev for FS_COMBINED.
2959   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2960   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
2961   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
2962   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // linkage
2963   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
2964   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
2965   // numrefs x valueid, n x (valueid, callsitecount)
2966   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2967   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2968   unsigned FSCallsAbbrev = Stream.EmitAbbrev(Abbv);
2969 
2970   // Abbrev for FS_COMBINED_PROFILE.
2971   Abbv = new BitCodeAbbrev();
2972   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
2973   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
2974   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // linkage
2975   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
2976   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
2977   // numrefs x valueid, n x (valueid, callsitecount, profilecount)
2978   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2979   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2980   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(Abbv);
2981 
2982   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
2983   Abbv = new BitCodeAbbrev();
2984   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
2985   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
2986   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // linkage
2987   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
2988   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2989   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(Abbv);
2990 
2991   SmallVector<uint64_t, 64> NameVals;
2992   for (const auto &FII : Index) {
2993     for (auto &FI : FII.second) {
2994       GlobalValueSummary *S = FI->summary();
2995       assert(S);
2996 
2997       if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
2998         NameVals.push_back(Index.getModuleId(VS->modulePath()));
2999         NameVals.push_back(getEncodedLinkage(VS->linkage()));
3000         for (auto &RI : VS->refs()) {
3001           const auto &VMI = GUIDToValueIdMap.find(RI.getGUID());
3002           unsigned RefId;
3003           // If this GUID doesn't have an entry, assign one.
3004           if (VMI == GUIDToValueIdMap.end()) {
3005             GUIDToValueIdMap[RI.getGUID()] = ++GlobalValueId;
3006             RefId = GlobalValueId;
3007           } else {
3008             RefId = VMI->second;
3009           }
3010           NameVals.push_back(RefId);
3011         }
3012 
3013         // Record the starting offset of this summary entry for use
3014         // in the VST entry. Add the current code size since the
3015         // reader will invoke readRecord after the abbrev id read.
3016         FI->setBitcodeIndex(Stream.GetCurrentBitNo() +
3017                             Stream.GetAbbrevIDWidth());
3018 
3019         // Emit the finished record.
3020         Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
3021                           FSModRefsAbbrev);
3022         NameVals.clear();
3023         continue;
3024       }
3025 
3026       auto *FS = cast<FunctionSummary>(S);
3027       NameVals.push_back(Index.getModuleId(FS->modulePath()));
3028       NameVals.push_back(getEncodedLinkage(FS->linkage()));
3029       NameVals.push_back(FS->instCount());
3030       NameVals.push_back(FS->refs().size());
3031 
3032       for (auto &RI : FS->refs()) {
3033         const auto &VMI = GUIDToValueIdMap.find(RI.getGUID());
3034         unsigned RefId;
3035         // If this GUID doesn't have an entry, assign one.
3036         if (VMI == GUIDToValueIdMap.end()) {
3037           GUIDToValueIdMap[RI.getGUID()] = ++GlobalValueId;
3038           RefId = GlobalValueId;
3039         } else {
3040           RefId = VMI->second;
3041         }
3042         NameVals.push_back(RefId);
3043       }
3044 
3045       bool HasProfileData = false;
3046       for (auto &EI : FS->calls()) {
3047         HasProfileData |= EI.second.ProfileCount != 0;
3048         if (HasProfileData)
3049           break;
3050       }
3051 
3052       for (auto &EI : FS->calls()) {
3053         const auto &VMI = GUIDToValueIdMap.find(EI.first.getGUID());
3054         // If this GUID doesn't have an entry, it doesn't have a function
3055         // summary and we don't need to record any calls to it.
3056         if (VMI == GUIDToValueIdMap.end())
3057           continue;
3058         NameVals.push_back(VMI->second);
3059         assert(EI.second.CallsiteCount > 0 && "Expected at least one callsite");
3060         NameVals.push_back(EI.second.CallsiteCount);
3061         if (HasProfileData)
3062           NameVals.push_back(EI.second.ProfileCount);
3063       }
3064 
3065       // Record the starting offset of this summary entry for use
3066       // in the VST entry. Add the current code size since the
3067       // reader will invoke readRecord after the abbrev id read.
3068       FI->setBitcodeIndex(Stream.GetCurrentBitNo() + Stream.GetAbbrevIDWidth());
3069 
3070       unsigned FSAbbrev =
3071           (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3072       unsigned Code =
3073           (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
3074 
3075       // Emit the finished record.
3076       Stream.EmitRecord(Code, NameVals, FSAbbrev);
3077       NameVals.clear();
3078     }
3079   }
3080 
3081   Stream.ExitBlock();
3082 }
3083 
3084 // Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
3085 // current llvm version, and a record for the epoch number.
3086 static void WriteIdentificationBlock(const Module *M, BitstreamWriter &Stream) {
3087   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
3088 
3089   // Write the "user readable" string identifying the bitcode producer
3090   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3091   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
3092   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3093   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3094   auto StringAbbrev = Stream.EmitAbbrev(Abbv);
3095   WriteStringRecord(bitc::IDENTIFICATION_CODE_STRING,
3096                     "LLVM" LLVM_VERSION_STRING, StringAbbrev, Stream);
3097 
3098   // Write the epoch version
3099   Abbv = new BitCodeAbbrev();
3100   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
3101   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3102   auto EpochAbbrev = Stream.EmitAbbrev(Abbv);
3103   SmallVector<unsigned, 1> Vals = {bitc::BITCODE_CURRENT_EPOCH};
3104   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
3105   Stream.ExitBlock();
3106 }
3107 
3108 static void writeModuleHash(BitstreamWriter &Stream,
3109                             SmallVectorImpl<char> &Buffer,
3110                             size_t BlockStartPos) {
3111   // Emit the module's hash.
3112   // MODULE_CODE_HASH: [5*i32]
3113   SHA1 Hasher;
3114   Hasher.update(ArrayRef<uint8_t>((uint8_t *)&Buffer[BlockStartPos],
3115                                   Buffer.size() - BlockStartPos));
3116   auto Hash = Hasher.result();
3117   SmallVector<uint64_t, 20> Vals;
3118   auto LShift = [&](unsigned char Val, unsigned Amount)
3119                     -> uint64_t { return ((uint64_t)Val) << Amount; };
3120   for (int Pos = 0; Pos < 20; Pos += 4) {
3121     uint32_t SubHash = LShift(Hash[Pos + 0], 24);
3122     SubHash |= LShift(Hash[Pos + 1], 16) | LShift(Hash[Pos + 2], 8) |
3123                (unsigned)(unsigned char)Hash[Pos + 3];
3124     Vals.push_back(SubHash);
3125   }
3126 
3127   // Emit the finished record.
3128   Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
3129 }
3130 
3131 /// WriteModule - Emit the specified module to the bitstream.
3132 static void WriteModule(const Module *M, BitstreamWriter &Stream,
3133                         bool ShouldPreserveUseListOrder,
3134                         uint64_t BitcodeStartBit,
3135                         const ModuleSummaryIndex *Index, bool GenerateHash,
3136                         SmallVectorImpl<char> &Buffer) {
3137   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
3138   size_t BlockStartPos = Buffer.size();
3139 
3140   SmallVector<unsigned, 1> Vals;
3141   unsigned CurVersion = 1;
3142   Vals.push_back(CurVersion);
3143   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
3144 
3145   // Analyze the module, enumerating globals, functions, etc.
3146   ValueEnumerator VE(*M, ShouldPreserveUseListOrder);
3147 
3148   // Emit blockinfo, which defines the standard abbreviations etc.
3149   WriteBlockInfo(VE, Stream);
3150 
3151   // Emit information about attribute groups.
3152   WriteAttributeGroupTable(VE, Stream);
3153 
3154   // Emit information about parameter attributes.
3155   WriteAttributeTable(VE, Stream);
3156 
3157   // Emit information describing all of the types in the module.
3158   WriteTypeTable(VE, Stream);
3159 
3160   writeComdats(VE, Stream);
3161 
3162   // Emit top-level description of module, including target triple, inline asm,
3163   // descriptors for global variables, and function prototype info.
3164   uint64_t VSTOffsetPlaceholder = WriteModuleInfo(M, VE, Stream);
3165 
3166   // Emit constants.
3167   WriteModuleConstants(VE, Stream);
3168 
3169   // Emit metadata.
3170   writeModuleMetadata(*M, VE, Stream);
3171 
3172   // Emit metadata.
3173   WriteModuleMetadataStore(M, Stream);
3174 
3175   // Emit module-level use-lists.
3176   if (VE.shouldPreserveUseListOrder())
3177     WriteUseListBlock(nullptr, VE, Stream);
3178 
3179   WriteOperandBundleTags(M, Stream);
3180 
3181   // Emit function bodies.
3182   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
3183   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
3184     if (!F->isDeclaration())
3185       WriteFunction(*F, M, VE, Stream, FunctionToBitcodeIndex);
3186 
3187   // Need to write after the above call to WriteFunction which populates
3188   // the summary information in the index.
3189   if (Index)
3190     WritePerModuleGlobalValueSummary(M, *Index, VE, Stream);
3191 
3192   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream,
3193                         VSTOffsetPlaceholder, BitcodeStartBit,
3194                         &FunctionToBitcodeIndex);
3195 
3196   if (GenerateHash) {
3197     writeModuleHash(Stream, Buffer, BlockStartPos);
3198   }
3199 
3200   Stream.ExitBlock();
3201 }
3202 
3203 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
3204 /// header and trailer to make it compatible with the system archiver.  To do
3205 /// this we emit the following header, and then emit a trailer that pads the
3206 /// file out to be a multiple of 16 bytes.
3207 ///
3208 /// struct bc_header {
3209 ///   uint32_t Magic;         // 0x0B17C0DE
3210 ///   uint32_t Version;       // Version, currently always 0.
3211 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
3212 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
3213 ///   uint32_t CPUType;       // CPU specifier.
3214 ///   ... potentially more later ...
3215 /// };
3216 
3217 static void WriteInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
3218                                uint32_t &Position) {
3219   support::endian::write32le(&Buffer[Position], Value);
3220   Position += 4;
3221 }
3222 
3223 static void EmitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
3224                                          const Triple &TT) {
3225   unsigned CPUType = ~0U;
3226 
3227   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
3228   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
3229   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
3230   // specific constants here because they are implicitly part of the Darwin ABI.
3231   enum {
3232     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
3233     DARWIN_CPU_TYPE_X86        = 7,
3234     DARWIN_CPU_TYPE_ARM        = 12,
3235     DARWIN_CPU_TYPE_POWERPC    = 18
3236   };
3237 
3238   Triple::ArchType Arch = TT.getArch();
3239   if (Arch == Triple::x86_64)
3240     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
3241   else if (Arch == Triple::x86)
3242     CPUType = DARWIN_CPU_TYPE_X86;
3243   else if (Arch == Triple::ppc)
3244     CPUType = DARWIN_CPU_TYPE_POWERPC;
3245   else if (Arch == Triple::ppc64)
3246     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
3247   else if (Arch == Triple::arm || Arch == Triple::thumb)
3248     CPUType = DARWIN_CPU_TYPE_ARM;
3249 
3250   // Traditional Bitcode starts after header.
3251   assert(Buffer.size() >= BWH_HeaderSize &&
3252          "Expected header size to be reserved");
3253   unsigned BCOffset = BWH_HeaderSize;
3254   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
3255 
3256   // Write the magic and version.
3257   unsigned Position = 0;
3258   WriteInt32ToBuffer(0x0B17C0DE , Buffer, Position);
3259   WriteInt32ToBuffer(0          , Buffer, Position); // Version.
3260   WriteInt32ToBuffer(BCOffset   , Buffer, Position);
3261   WriteInt32ToBuffer(BCSize     , Buffer, Position);
3262   WriteInt32ToBuffer(CPUType    , Buffer, Position);
3263 
3264   // If the file is not a multiple of 16 bytes, insert dummy padding.
3265   while (Buffer.size() & 15)
3266     Buffer.push_back(0);
3267 }
3268 
3269 /// Helper to write the header common to all bitcode files.
3270 static void WriteBitcodeHeader(BitstreamWriter &Stream) {
3271   // Emit the file header.
3272   Stream.Emit((unsigned)'B', 8);
3273   Stream.Emit((unsigned)'C', 8);
3274   Stream.Emit(0x0, 4);
3275   Stream.Emit(0xC, 4);
3276   Stream.Emit(0xE, 4);
3277   Stream.Emit(0xD, 4);
3278 }
3279 
3280 /// WriteBitcodeToFile - Write the specified module to the specified output
3281 /// stream.
3282 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out,
3283                               bool ShouldPreserveUseListOrder,
3284                               const ModuleSummaryIndex *Index,
3285                               bool GenerateHash) {
3286   SmallVector<char, 0> Buffer;
3287   Buffer.reserve(256*1024);
3288 
3289   // If this is darwin or another generic macho target, reserve space for the
3290   // header.
3291   Triple TT(M->getTargetTriple());
3292   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
3293     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
3294 
3295   // Emit the module into the buffer.
3296   {
3297     BitstreamWriter Stream(Buffer);
3298     // Save the start bit of the actual bitcode, in case there is space
3299     // saved at the start for the darwin header above. The reader stream
3300     // will start at the bitcode, and we need the offset of the VST
3301     // to line up.
3302     uint64_t BitcodeStartBit = Stream.GetCurrentBitNo();
3303 
3304     // Emit the file header.
3305     WriteBitcodeHeader(Stream);
3306 
3307     WriteIdentificationBlock(M, Stream);
3308 
3309     // Emit the module.
3310     WriteModule(M, Stream, ShouldPreserveUseListOrder, BitcodeStartBit, Index,
3311                 GenerateHash, Buffer);
3312   }
3313 
3314   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
3315     EmitDarwinBCHeaderAndTrailer(Buffer, TT);
3316 
3317   // Write the generated bitstream to "Out".
3318   Out.write((char*)&Buffer.front(), Buffer.size());
3319 }
3320 
3321 // Write the specified module summary index to the given raw output stream,
3322 // where it will be written in a new bitcode block. This is used when
3323 // writing the combined index file for ThinLTO.
3324 void llvm::WriteIndexToFile(const ModuleSummaryIndex &Index, raw_ostream &Out) {
3325   SmallVector<char, 0> Buffer;
3326   Buffer.reserve(256 * 1024);
3327 
3328   BitstreamWriter Stream(Buffer);
3329 
3330   // Emit the bitcode header.
3331   WriteBitcodeHeader(Stream);
3332 
3333   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
3334 
3335   SmallVector<unsigned, 1> Vals;
3336   unsigned CurVersion = 1;
3337   Vals.push_back(CurVersion);
3338   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
3339 
3340   // If we have a VST, write the VSTOFFSET record placeholder and record
3341   // its offset.
3342   uint64_t VSTOffsetPlaceholder = WriteValueSymbolTableForwardDecl(Stream);
3343 
3344   // Write the module paths in the combined index.
3345   WriteModStrings(Index, Stream);
3346 
3347   // Assign unique value ids to all functions in the index for use
3348   // in writing out the call graph edges. Save the mapping from GUID
3349   // to the new global value id to use when writing those edges, which
3350   // are currently saved in the index in terms of GUID.
3351   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
3352   unsigned GlobalValueId = 0;
3353   for (auto &II : Index)
3354     GUIDToValueIdMap[II.first] = ++GlobalValueId;
3355 
3356   // Write the summary combined index records.
3357   WriteCombinedGlobalValueSummary(Index, Stream, GUIDToValueIdMap,
3358                                   GlobalValueId);
3359 
3360   // Need a special VST writer for the combined index (we don't have a
3361   // real VST and real values when this is invoked).
3362   WriteCombinedValueSymbolTable(Index, Stream, GUIDToValueIdMap,
3363                                 VSTOffsetPlaceholder);
3364 
3365   Stream.ExitBlock();
3366 
3367   Out.write((char *)&Buffer.front(), Buffer.size());
3368 }
3369