1 //===- BitcodeReader.cpp - Internal BitcodeReader implementation ----------===//
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 #include "llvm/Bitcode/ReaderWriter.h"
11 #include "BitcodeReader.h"
12 #include "llvm/ADT/STLExtras.h"
13 #include "llvm/ADT/SmallString.h"
14 #include "llvm/ADT/SmallVector.h"
15 #include "llvm/ADT/Triple.h"
16 #include "llvm/Bitcode/LLVMBitCodes.h"
17 #include "llvm/IR/AutoUpgrade.h"
18 #include "llvm/IR/Constants.h"
19 #include "llvm/IR/DebugInfoMetadata.h"
20 #include "llvm/IR/DerivedTypes.h"
21 #include "llvm/IR/DiagnosticPrinter.h"
22 #include "llvm/IR/InlineAsm.h"
23 #include "llvm/IR/IntrinsicInst.h"
24 #include "llvm/IR/LLVMContext.h"
25 #include "llvm/IR/Module.h"
26 #include "llvm/IR/OperandTraits.h"
27 #include "llvm/IR/Operator.h"
28 #include "llvm/Support/DataStream.h"
29 #include "llvm/Support/ManagedStatic.h"
30 #include "llvm/Support/MathExtras.h"
31 #include "llvm/Support/MemoryBuffer.h"
32 #include "llvm/Support/raw_ostream.h"
33 
34 using namespace llvm;
35 
36 enum {
37   SWITCH_INST_MAGIC = 0x4B5 // May 2012 => 1205 => Hex
38 };
39 
40 BitcodeDiagnosticInfo::BitcodeDiagnosticInfo(std::error_code EC,
41                                              DiagnosticSeverity Severity,
42                                              const Twine &Msg)
43     : DiagnosticInfo(DK_Bitcode, Severity), Msg(Msg), EC(EC) {}
44 
45 void BitcodeDiagnosticInfo::print(DiagnosticPrinter &DP) const { DP << Msg; }
46 
47 static std::error_code Error(DiagnosticHandlerFunction DiagnosticHandler,
48                              std::error_code EC, const Twine &Message) {
49   BitcodeDiagnosticInfo DI(EC, DS_Error, Message);
50   DiagnosticHandler(DI);
51   return EC;
52 }
53 
54 static std::error_code Error(DiagnosticHandlerFunction DiagnosticHandler,
55                              std::error_code EC) {
56   return Error(DiagnosticHandler, EC, EC.message());
57 }
58 
59 std::error_code BitcodeReader::Error(BitcodeError E, const Twine &Message) {
60   return ::Error(DiagnosticHandler, make_error_code(E), Message);
61 }
62 
63 std::error_code BitcodeReader::Error(const Twine &Message) {
64   return ::Error(DiagnosticHandler,
65                  make_error_code(BitcodeError::CorruptedBitcode), Message);
66 }
67 
68 std::error_code BitcodeReader::Error(BitcodeError E) {
69   return ::Error(DiagnosticHandler, make_error_code(E));
70 }
71 
72 static DiagnosticHandlerFunction getDiagHandler(DiagnosticHandlerFunction F,
73                                                 LLVMContext &C) {
74   if (F)
75     return F;
76   return [&C](const DiagnosticInfo &DI) { C.diagnose(DI); };
77 }
78 
79 BitcodeReader::BitcodeReader(MemoryBuffer *buffer, LLVMContext &C,
80                              DiagnosticHandlerFunction DiagnosticHandler)
81     : Context(C), DiagnosticHandler(getDiagHandler(DiagnosticHandler, C)),
82       TheModule(nullptr), Buffer(buffer), LazyStreamer(nullptr),
83       NextUnreadBit(0), SeenValueSymbolTable(false), ValueList(C),
84       MDValueList(C), SeenFirstFunctionBody(false), UseRelativeIDs(false),
85       WillMaterializeAllForwardRefs(false) {}
86 
87 BitcodeReader::BitcodeReader(DataStreamer *streamer, LLVMContext &C,
88                              DiagnosticHandlerFunction DiagnosticHandler)
89     : Context(C), DiagnosticHandler(getDiagHandler(DiagnosticHandler, C)),
90       TheModule(nullptr), Buffer(nullptr), LazyStreamer(streamer),
91       NextUnreadBit(0), SeenValueSymbolTable(false), ValueList(C),
92       MDValueList(C), SeenFirstFunctionBody(false), UseRelativeIDs(false),
93       WillMaterializeAllForwardRefs(false) {}
94 
95 std::error_code BitcodeReader::materializeForwardReferencedFunctions() {
96   if (WillMaterializeAllForwardRefs)
97     return std::error_code();
98 
99   // Prevent recursion.
100   WillMaterializeAllForwardRefs = true;
101 
102   while (!BasicBlockFwdRefQueue.empty()) {
103     Function *F = BasicBlockFwdRefQueue.front();
104     BasicBlockFwdRefQueue.pop_front();
105     assert(F && "Expected valid function");
106     if (!BasicBlockFwdRefs.count(F))
107       // Already materialized.
108       continue;
109 
110     // Check for a function that isn't materializable to prevent an infinite
111     // loop.  When parsing a blockaddress stored in a global variable, there
112     // isn't a trivial way to check if a function will have a body without a
113     // linear search through FunctionsWithBodies, so just check it here.
114     if (!F->isMaterializable())
115       return Error("Never resolved function from blockaddress");
116 
117     // Try to materialize F.
118     if (std::error_code EC = materialize(F))
119       return EC;
120   }
121   assert(BasicBlockFwdRefs.empty() && "Function missing from queue");
122 
123   // Reset state.
124   WillMaterializeAllForwardRefs = false;
125   return std::error_code();
126 }
127 
128 void BitcodeReader::FreeState() {
129   Buffer = nullptr;
130   std::vector<Type*>().swap(TypeList);
131   ValueList.clear();
132   MDValueList.clear();
133   std::vector<Comdat *>().swap(ComdatList);
134 
135   std::vector<AttributeSet>().swap(MAttributes);
136   std::vector<BasicBlock*>().swap(FunctionBBs);
137   std::vector<Function*>().swap(FunctionsWithBodies);
138   DeferredFunctionInfo.clear();
139   MDKindMap.clear();
140 
141   assert(BasicBlockFwdRefs.empty() && "Unresolved blockaddress fwd references");
142   BasicBlockFwdRefQueue.clear();
143 }
144 
145 //===----------------------------------------------------------------------===//
146 //  Helper functions to implement forward reference resolution, etc.
147 //===----------------------------------------------------------------------===//
148 
149 /// ConvertToString - Convert a string from a record into an std::string, return
150 /// true on failure.
151 template<typename StrTy>
152 static bool ConvertToString(ArrayRef<uint64_t> Record, unsigned Idx,
153                             StrTy &Result) {
154   if (Idx > Record.size())
155     return true;
156 
157   for (unsigned i = Idx, e = Record.size(); i != e; ++i)
158     Result += (char)Record[i];
159   return false;
160 }
161 
162 static bool hasImplicitComdat(size_t Val) {
163   switch (Val) {
164   default:
165     return false;
166   case 1:  // Old WeakAnyLinkage
167   case 4:  // Old LinkOnceAnyLinkage
168   case 10: // Old WeakODRLinkage
169   case 11: // Old LinkOnceODRLinkage
170     return true;
171   }
172 }
173 
174 static GlobalValue::LinkageTypes getDecodedLinkage(unsigned Val) {
175   switch (Val) {
176   default: // Map unknown/new linkages to external
177   case 0:
178     return GlobalValue::ExternalLinkage;
179   case 2:
180     return GlobalValue::AppendingLinkage;
181   case 3:
182     return GlobalValue::InternalLinkage;
183   case 5:
184     return GlobalValue::ExternalLinkage; // Obsolete DLLImportLinkage
185   case 6:
186     return GlobalValue::ExternalLinkage; // Obsolete DLLExportLinkage
187   case 7:
188     return GlobalValue::ExternalWeakLinkage;
189   case 8:
190     return GlobalValue::CommonLinkage;
191   case 9:
192     return GlobalValue::PrivateLinkage;
193   case 12:
194     return GlobalValue::AvailableExternallyLinkage;
195   case 13:
196     return GlobalValue::PrivateLinkage; // Obsolete LinkerPrivateLinkage
197   case 14:
198     return GlobalValue::PrivateLinkage; // Obsolete LinkerPrivateWeakLinkage
199   case 15:
200     return GlobalValue::ExternalLinkage; // Obsolete LinkOnceODRAutoHideLinkage
201   case 1: // Old value with implicit comdat.
202   case 16:
203     return GlobalValue::WeakAnyLinkage;
204   case 10: // Old value with implicit comdat.
205   case 17:
206     return GlobalValue::WeakODRLinkage;
207   case 4: // Old value with implicit comdat.
208   case 18:
209     return GlobalValue::LinkOnceAnyLinkage;
210   case 11: // Old value with implicit comdat.
211   case 19:
212     return GlobalValue::LinkOnceODRLinkage;
213   }
214 }
215 
216 static GlobalValue::VisibilityTypes GetDecodedVisibility(unsigned Val) {
217   switch (Val) {
218   default: // Map unknown visibilities to default.
219   case 0: return GlobalValue::DefaultVisibility;
220   case 1: return GlobalValue::HiddenVisibility;
221   case 2: return GlobalValue::ProtectedVisibility;
222   }
223 }
224 
225 static GlobalValue::DLLStorageClassTypes
226 GetDecodedDLLStorageClass(unsigned Val) {
227   switch (Val) {
228   default: // Map unknown values to default.
229   case 0: return GlobalValue::DefaultStorageClass;
230   case 1: return GlobalValue::DLLImportStorageClass;
231   case 2: return GlobalValue::DLLExportStorageClass;
232   }
233 }
234 
235 static GlobalVariable::ThreadLocalMode GetDecodedThreadLocalMode(unsigned Val) {
236   switch (Val) {
237     case 0: return GlobalVariable::NotThreadLocal;
238     default: // Map unknown non-zero value to general dynamic.
239     case 1: return GlobalVariable::GeneralDynamicTLSModel;
240     case 2: return GlobalVariable::LocalDynamicTLSModel;
241     case 3: return GlobalVariable::InitialExecTLSModel;
242     case 4: return GlobalVariable::LocalExecTLSModel;
243   }
244 }
245 
246 static int GetDecodedCastOpcode(unsigned Val) {
247   switch (Val) {
248   default: return -1;
249   case bitc::CAST_TRUNC   : return Instruction::Trunc;
250   case bitc::CAST_ZEXT    : return Instruction::ZExt;
251   case bitc::CAST_SEXT    : return Instruction::SExt;
252   case bitc::CAST_FPTOUI  : return Instruction::FPToUI;
253   case bitc::CAST_FPTOSI  : return Instruction::FPToSI;
254   case bitc::CAST_UITOFP  : return Instruction::UIToFP;
255   case bitc::CAST_SITOFP  : return Instruction::SIToFP;
256   case bitc::CAST_FPTRUNC : return Instruction::FPTrunc;
257   case bitc::CAST_FPEXT   : return Instruction::FPExt;
258   case bitc::CAST_PTRTOINT: return Instruction::PtrToInt;
259   case bitc::CAST_INTTOPTR: return Instruction::IntToPtr;
260   case bitc::CAST_BITCAST : return Instruction::BitCast;
261   case bitc::CAST_ADDRSPACECAST: return Instruction::AddrSpaceCast;
262   }
263 }
264 static int GetDecodedBinaryOpcode(unsigned Val, Type *Ty) {
265   switch (Val) {
266   default: return -1;
267   case bitc::BINOP_ADD:
268     return Ty->isFPOrFPVectorTy() ? Instruction::FAdd : Instruction::Add;
269   case bitc::BINOP_SUB:
270     return Ty->isFPOrFPVectorTy() ? Instruction::FSub : Instruction::Sub;
271   case bitc::BINOP_MUL:
272     return Ty->isFPOrFPVectorTy() ? Instruction::FMul : Instruction::Mul;
273   case bitc::BINOP_UDIV: return Instruction::UDiv;
274   case bitc::BINOP_SDIV:
275     return Ty->isFPOrFPVectorTy() ? Instruction::FDiv : Instruction::SDiv;
276   case bitc::BINOP_UREM: return Instruction::URem;
277   case bitc::BINOP_SREM:
278     return Ty->isFPOrFPVectorTy() ? Instruction::FRem : Instruction::SRem;
279   case bitc::BINOP_SHL:  return Instruction::Shl;
280   case bitc::BINOP_LSHR: return Instruction::LShr;
281   case bitc::BINOP_ASHR: return Instruction::AShr;
282   case bitc::BINOP_AND:  return Instruction::And;
283   case bitc::BINOP_OR:   return Instruction::Or;
284   case bitc::BINOP_XOR:  return Instruction::Xor;
285   }
286 }
287 
288 static AtomicRMWInst::BinOp GetDecodedRMWOperation(unsigned Val) {
289   switch (Val) {
290   default: return AtomicRMWInst::BAD_BINOP;
291   case bitc::RMW_XCHG: return AtomicRMWInst::Xchg;
292   case bitc::RMW_ADD: return AtomicRMWInst::Add;
293   case bitc::RMW_SUB: return AtomicRMWInst::Sub;
294   case bitc::RMW_AND: return AtomicRMWInst::And;
295   case bitc::RMW_NAND: return AtomicRMWInst::Nand;
296   case bitc::RMW_OR: return AtomicRMWInst::Or;
297   case bitc::RMW_XOR: return AtomicRMWInst::Xor;
298   case bitc::RMW_MAX: return AtomicRMWInst::Max;
299   case bitc::RMW_MIN: return AtomicRMWInst::Min;
300   case bitc::RMW_UMAX: return AtomicRMWInst::UMax;
301   case bitc::RMW_UMIN: return AtomicRMWInst::UMin;
302   }
303 }
304 
305 static AtomicOrdering GetDecodedOrdering(unsigned Val) {
306   switch (Val) {
307   case bitc::ORDERING_NOTATOMIC: return NotAtomic;
308   case bitc::ORDERING_UNORDERED: return Unordered;
309   case bitc::ORDERING_MONOTONIC: return Monotonic;
310   case bitc::ORDERING_ACQUIRE: return Acquire;
311   case bitc::ORDERING_RELEASE: return Release;
312   case bitc::ORDERING_ACQREL: return AcquireRelease;
313   default: // Map unknown orderings to sequentially-consistent.
314   case bitc::ORDERING_SEQCST: return SequentiallyConsistent;
315   }
316 }
317 
318 static SynchronizationScope GetDecodedSynchScope(unsigned Val) {
319   switch (Val) {
320   case bitc::SYNCHSCOPE_SINGLETHREAD: return SingleThread;
321   default: // Map unknown scopes to cross-thread.
322   case bitc::SYNCHSCOPE_CROSSTHREAD: return CrossThread;
323   }
324 }
325 
326 static Comdat::SelectionKind getDecodedComdatSelectionKind(unsigned Val) {
327   switch (Val) {
328   default: // Map unknown selection kinds to any.
329   case bitc::COMDAT_SELECTION_KIND_ANY:
330     return Comdat::Any;
331   case bitc::COMDAT_SELECTION_KIND_EXACT_MATCH:
332     return Comdat::ExactMatch;
333   case bitc::COMDAT_SELECTION_KIND_LARGEST:
334     return Comdat::Largest;
335   case bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES:
336     return Comdat::NoDuplicates;
337   case bitc::COMDAT_SELECTION_KIND_SAME_SIZE:
338     return Comdat::SameSize;
339   }
340 }
341 
342 static void UpgradeDLLImportExportLinkage(llvm::GlobalValue *GV, unsigned Val) {
343   switch (Val) {
344   case 5: GV->setDLLStorageClass(GlobalValue::DLLImportStorageClass); break;
345   case 6: GV->setDLLStorageClass(GlobalValue::DLLExportStorageClass); break;
346   }
347 }
348 
349 namespace llvm {
350 namespace {
351   /// @brief A class for maintaining the slot number definition
352   /// as a placeholder for the actual definition for forward constants defs.
353   class ConstantPlaceHolder : public ConstantExpr {
354     void operator=(const ConstantPlaceHolder &) = delete;
355   public:
356     // allocate space for exactly one operand
357     void *operator new(size_t s) {
358       return User::operator new(s, 1);
359     }
360     explicit ConstantPlaceHolder(Type *Ty, LLVMContext& Context)
361       : ConstantExpr(Ty, Instruction::UserOp1, &Op<0>(), 1) {
362       Op<0>() = UndefValue::get(Type::getInt32Ty(Context));
363     }
364 
365     /// @brief Methods to support type inquiry through isa, cast, and dyn_cast.
366     static bool classof(const Value *V) {
367       return isa<ConstantExpr>(V) &&
368              cast<ConstantExpr>(V)->getOpcode() == Instruction::UserOp1;
369     }
370 
371 
372     /// Provide fast operand accessors
373     DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
374   };
375 }
376 
377 // FIXME: can we inherit this from ConstantExpr?
378 template <>
379 struct OperandTraits<ConstantPlaceHolder> :
380   public FixedNumOperandTraits<ConstantPlaceHolder, 1> {
381 };
382 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(ConstantPlaceHolder, Value)
383 }
384 
385 
386 void BitcodeReaderValueList::AssignValue(Value *V, unsigned Idx) {
387   if (Idx == size()) {
388     push_back(V);
389     return;
390   }
391 
392   if (Idx >= size())
393     resize(Idx+1);
394 
395   WeakVH &OldV = ValuePtrs[Idx];
396   if (!OldV) {
397     OldV = V;
398     return;
399   }
400 
401   // Handle constants and non-constants (e.g. instrs) differently for
402   // efficiency.
403   if (Constant *PHC = dyn_cast<Constant>(&*OldV)) {
404     ResolveConstants.push_back(std::make_pair(PHC, Idx));
405     OldV = V;
406   } else {
407     // If there was a forward reference to this value, replace it.
408     Value *PrevVal = OldV;
409     OldV->replaceAllUsesWith(V);
410     delete PrevVal;
411   }
412 }
413 
414 
415 Constant *BitcodeReaderValueList::getConstantFwdRef(unsigned Idx,
416                                                     Type *Ty) {
417   if (Idx >= size())
418     resize(Idx + 1);
419 
420   if (Value *V = ValuePtrs[Idx]) {
421     assert(Ty == V->getType() && "Type mismatch in constant table!");
422     return cast<Constant>(V);
423   }
424 
425   // Create and return a placeholder, which will later be RAUW'd.
426   Constant *C = new ConstantPlaceHolder(Ty, Context);
427   ValuePtrs[Idx] = C;
428   return C;
429 }
430 
431 Value *BitcodeReaderValueList::getValueFwdRef(unsigned Idx, Type *Ty) {
432   if (Idx >= size())
433     resize(Idx + 1);
434 
435   if (Value *V = ValuePtrs[Idx]) {
436     assert((!Ty || Ty == V->getType()) && "Type mismatch in value table!");
437     return V;
438   }
439 
440   // No type specified, must be invalid reference.
441   if (!Ty) return nullptr;
442 
443   // Create and return a placeholder, which will later be RAUW'd.
444   Value *V = new Argument(Ty);
445   ValuePtrs[Idx] = V;
446   return V;
447 }
448 
449 /// ResolveConstantForwardRefs - Once all constants are read, this method bulk
450 /// resolves any forward references.  The idea behind this is that we sometimes
451 /// get constants (such as large arrays) which reference *many* forward ref
452 /// constants.  Replacing each of these causes a lot of thrashing when
453 /// building/reuniquing the constant.  Instead of doing this, we look at all the
454 /// uses and rewrite all the place holders at once for any constant that uses
455 /// a placeholder.
456 void BitcodeReaderValueList::ResolveConstantForwardRefs() {
457   // Sort the values by-pointer so that they are efficient to look up with a
458   // binary search.
459   std::sort(ResolveConstants.begin(), ResolveConstants.end());
460 
461   SmallVector<Constant*, 64> NewOps;
462 
463   while (!ResolveConstants.empty()) {
464     Value *RealVal = operator[](ResolveConstants.back().second);
465     Constant *Placeholder = ResolveConstants.back().first;
466     ResolveConstants.pop_back();
467 
468     // Loop over all users of the placeholder, updating them to reference the
469     // new value.  If they reference more than one placeholder, update them all
470     // at once.
471     while (!Placeholder->use_empty()) {
472       auto UI = Placeholder->user_begin();
473       User *U = *UI;
474 
475       // If the using object isn't uniqued, just update the operands.  This
476       // handles instructions and initializers for global variables.
477       if (!isa<Constant>(U) || isa<GlobalValue>(U)) {
478         UI.getUse().set(RealVal);
479         continue;
480       }
481 
482       // Otherwise, we have a constant that uses the placeholder.  Replace that
483       // constant with a new constant that has *all* placeholder uses updated.
484       Constant *UserC = cast<Constant>(U);
485       for (User::op_iterator I = UserC->op_begin(), E = UserC->op_end();
486            I != E; ++I) {
487         Value *NewOp;
488         if (!isa<ConstantPlaceHolder>(*I)) {
489           // Not a placeholder reference.
490           NewOp = *I;
491         } else if (*I == Placeholder) {
492           // Common case is that it just references this one placeholder.
493           NewOp = RealVal;
494         } else {
495           // Otherwise, look up the placeholder in ResolveConstants.
496           ResolveConstantsTy::iterator It =
497             std::lower_bound(ResolveConstants.begin(), ResolveConstants.end(),
498                              std::pair<Constant*, unsigned>(cast<Constant>(*I),
499                                                             0));
500           assert(It != ResolveConstants.end() && It->first == *I);
501           NewOp = operator[](It->second);
502         }
503 
504         NewOps.push_back(cast<Constant>(NewOp));
505       }
506 
507       // Make the new constant.
508       Constant *NewC;
509       if (ConstantArray *UserCA = dyn_cast<ConstantArray>(UserC)) {
510         NewC = ConstantArray::get(UserCA->getType(), NewOps);
511       } else if (ConstantStruct *UserCS = dyn_cast<ConstantStruct>(UserC)) {
512         NewC = ConstantStruct::get(UserCS->getType(), NewOps);
513       } else if (isa<ConstantVector>(UserC)) {
514         NewC = ConstantVector::get(NewOps);
515       } else {
516         assert(isa<ConstantExpr>(UserC) && "Must be a ConstantExpr.");
517         NewC = cast<ConstantExpr>(UserC)->getWithOperands(NewOps);
518       }
519 
520       UserC->replaceAllUsesWith(NewC);
521       UserC->destroyConstant();
522       NewOps.clear();
523     }
524 
525     // Update all ValueHandles, they should be the only users at this point.
526     Placeholder->replaceAllUsesWith(RealVal);
527     delete Placeholder;
528   }
529 }
530 
531 void BitcodeReaderMDValueList::AssignValue(Metadata *MD, unsigned Idx) {
532   if (Idx == size()) {
533     push_back(MD);
534     return;
535   }
536 
537   if (Idx >= size())
538     resize(Idx+1);
539 
540   TrackingMDRef &OldMD = MDValuePtrs[Idx];
541   if (!OldMD) {
542     OldMD.reset(MD);
543     return;
544   }
545 
546   // If there was a forward reference to this value, replace it.
547   TempMDTuple PrevMD(cast<MDTuple>(OldMD.get()));
548   PrevMD->replaceAllUsesWith(MD);
549   --NumFwdRefs;
550 }
551 
552 Metadata *BitcodeReaderMDValueList::getValueFwdRef(unsigned Idx) {
553   if (Idx >= size())
554     resize(Idx + 1);
555 
556   if (Metadata *MD = MDValuePtrs[Idx])
557     return MD;
558 
559   // Track forward refs to be resolved later.
560   if (AnyFwdRefs) {
561     MinFwdRef = std::min(MinFwdRef, Idx);
562     MaxFwdRef = std::max(MaxFwdRef, Idx);
563   } else {
564     AnyFwdRefs = true;
565     MinFwdRef = MaxFwdRef = Idx;
566   }
567   ++NumFwdRefs;
568 
569   // Create and return a placeholder, which will later be RAUW'd.
570   Metadata *MD = MDNode::getTemporary(Context, None).release();
571   MDValuePtrs[Idx].reset(MD);
572   return MD;
573 }
574 
575 void BitcodeReaderMDValueList::tryToResolveCycles() {
576   if (!AnyFwdRefs)
577     // Nothing to do.
578     return;
579 
580   if (NumFwdRefs)
581     // Still forward references... can't resolve cycles.
582     return;
583 
584   // Resolve any cycles.
585   for (unsigned I = MinFwdRef, E = MaxFwdRef + 1; I != E; ++I) {
586     auto &MD = MDValuePtrs[I];
587     auto *N = dyn_cast_or_null<MDNode>(MD);
588     if (!N)
589       continue;
590 
591     assert(!N->isTemporary() && "Unexpected forward reference");
592     N->resolveCycles();
593   }
594 
595   // Make sure we return early again until there's another forward ref.
596   AnyFwdRefs = false;
597 }
598 
599 Type *BitcodeReader::getTypeByID(unsigned ID) {
600   // The type table size is always specified correctly.
601   if (ID >= TypeList.size())
602     return nullptr;
603 
604   if (Type *Ty = TypeList[ID])
605     return Ty;
606 
607   // If we have a forward reference, the only possible case is when it is to a
608   // named struct.  Just create a placeholder for now.
609   return TypeList[ID] = createIdentifiedStructType(Context);
610 }
611 
612 StructType *BitcodeReader::createIdentifiedStructType(LLVMContext &Context,
613                                                       StringRef Name) {
614   auto *Ret = StructType::create(Context, Name);
615   IdentifiedStructTypes.push_back(Ret);
616   return Ret;
617 }
618 
619 StructType *BitcodeReader::createIdentifiedStructType(LLVMContext &Context) {
620   auto *Ret = StructType::create(Context);
621   IdentifiedStructTypes.push_back(Ret);
622   return Ret;
623 }
624 
625 
626 //===----------------------------------------------------------------------===//
627 //  Functions for parsing blocks from the bitcode file
628 //===----------------------------------------------------------------------===//
629 
630 
631 /// \brief This fills an AttrBuilder object with the LLVM attributes that have
632 /// been decoded from the given integer. This function must stay in sync with
633 /// 'encodeLLVMAttributesForBitcode'.
634 static void decodeLLVMAttributesForBitcode(AttrBuilder &B,
635                                            uint64_t EncodedAttrs) {
636   // FIXME: Remove in 4.0.
637 
638   // The alignment is stored as a 16-bit raw value from bits 31--16.  We shift
639   // the bits above 31 down by 11 bits.
640   unsigned Alignment = (EncodedAttrs & (0xffffULL << 16)) >> 16;
641   assert((!Alignment || isPowerOf2_32(Alignment)) &&
642          "Alignment must be a power of two.");
643 
644   if (Alignment)
645     B.addAlignmentAttr(Alignment);
646   B.addRawValue(((EncodedAttrs & (0xfffffULL << 32)) >> 11) |
647                 (EncodedAttrs & 0xffff));
648 }
649 
650 std::error_code BitcodeReader::ParseAttributeBlock() {
651   if (Stream.EnterSubBlock(bitc::PARAMATTR_BLOCK_ID))
652     return Error("Invalid record");
653 
654   if (!MAttributes.empty())
655     return Error("Invalid multiple blocks");
656 
657   SmallVector<uint64_t, 64> Record;
658 
659   SmallVector<AttributeSet, 8> Attrs;
660 
661   // Read all the records.
662   while (1) {
663     BitstreamEntry Entry = Stream.advanceSkippingSubblocks();
664 
665     switch (Entry.Kind) {
666     case BitstreamEntry::SubBlock: // Handled for us already.
667     case BitstreamEntry::Error:
668       return Error("Malformed block");
669     case BitstreamEntry::EndBlock:
670       return std::error_code();
671     case BitstreamEntry::Record:
672       // The interesting case.
673       break;
674     }
675 
676     // Read a record.
677     Record.clear();
678     switch (Stream.readRecord(Entry.ID, Record)) {
679     default:  // Default behavior: ignore.
680       break;
681     case bitc::PARAMATTR_CODE_ENTRY_OLD: { // ENTRY: [paramidx0, attr0, ...]
682       // FIXME: Remove in 4.0.
683       if (Record.size() & 1)
684         return Error("Invalid record");
685 
686       for (unsigned i = 0, e = Record.size(); i != e; i += 2) {
687         AttrBuilder B;
688         decodeLLVMAttributesForBitcode(B, Record[i+1]);
689         Attrs.push_back(AttributeSet::get(Context, Record[i], B));
690       }
691 
692       MAttributes.push_back(AttributeSet::get(Context, Attrs));
693       Attrs.clear();
694       break;
695     }
696     case bitc::PARAMATTR_CODE_ENTRY: { // ENTRY: [attrgrp0, attrgrp1, ...]
697       for (unsigned i = 0, e = Record.size(); i != e; ++i)
698         Attrs.push_back(MAttributeGroups[Record[i]]);
699 
700       MAttributes.push_back(AttributeSet::get(Context, Attrs));
701       Attrs.clear();
702       break;
703     }
704     }
705   }
706 }
707 
708 // Returns Attribute::None on unrecognized codes.
709 static Attribute::AttrKind GetAttrFromCode(uint64_t Code) {
710   switch (Code) {
711   default:
712     return Attribute::None;
713   case bitc::ATTR_KIND_ALIGNMENT:
714     return Attribute::Alignment;
715   case bitc::ATTR_KIND_ALWAYS_INLINE:
716     return Attribute::AlwaysInline;
717   case bitc::ATTR_KIND_BUILTIN:
718     return Attribute::Builtin;
719   case bitc::ATTR_KIND_BY_VAL:
720     return Attribute::ByVal;
721   case bitc::ATTR_KIND_IN_ALLOCA:
722     return Attribute::InAlloca;
723   case bitc::ATTR_KIND_COLD:
724     return Attribute::Cold;
725   case bitc::ATTR_KIND_INLINE_HINT:
726     return Attribute::InlineHint;
727   case bitc::ATTR_KIND_IN_REG:
728     return Attribute::InReg;
729   case bitc::ATTR_KIND_JUMP_TABLE:
730     return Attribute::JumpTable;
731   case bitc::ATTR_KIND_MIN_SIZE:
732     return Attribute::MinSize;
733   case bitc::ATTR_KIND_NAKED:
734     return Attribute::Naked;
735   case bitc::ATTR_KIND_NEST:
736     return Attribute::Nest;
737   case bitc::ATTR_KIND_NO_ALIAS:
738     return Attribute::NoAlias;
739   case bitc::ATTR_KIND_NO_BUILTIN:
740     return Attribute::NoBuiltin;
741   case bitc::ATTR_KIND_NO_CAPTURE:
742     return Attribute::NoCapture;
743   case bitc::ATTR_KIND_NO_DUPLICATE:
744     return Attribute::NoDuplicate;
745   case bitc::ATTR_KIND_NO_IMPLICIT_FLOAT:
746     return Attribute::NoImplicitFloat;
747   case bitc::ATTR_KIND_NO_INLINE:
748     return Attribute::NoInline;
749   case bitc::ATTR_KIND_NON_LAZY_BIND:
750     return Attribute::NonLazyBind;
751   case bitc::ATTR_KIND_NON_NULL:
752     return Attribute::NonNull;
753   case bitc::ATTR_KIND_DEREFERENCEABLE:
754     return Attribute::Dereferenceable;
755   case bitc::ATTR_KIND_NO_RED_ZONE:
756     return Attribute::NoRedZone;
757   case bitc::ATTR_KIND_NO_RETURN:
758     return Attribute::NoReturn;
759   case bitc::ATTR_KIND_NO_UNWIND:
760     return Attribute::NoUnwind;
761   case bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE:
762     return Attribute::OptimizeForSize;
763   case bitc::ATTR_KIND_OPTIMIZE_NONE:
764     return Attribute::OptimizeNone;
765   case bitc::ATTR_KIND_READ_NONE:
766     return Attribute::ReadNone;
767   case bitc::ATTR_KIND_READ_ONLY:
768     return Attribute::ReadOnly;
769   case bitc::ATTR_KIND_RETURNED:
770     return Attribute::Returned;
771   case bitc::ATTR_KIND_RETURNS_TWICE:
772     return Attribute::ReturnsTwice;
773   case bitc::ATTR_KIND_S_EXT:
774     return Attribute::SExt;
775   case bitc::ATTR_KIND_STACK_ALIGNMENT:
776     return Attribute::StackAlignment;
777   case bitc::ATTR_KIND_STACK_PROTECT:
778     return Attribute::StackProtect;
779   case bitc::ATTR_KIND_STACK_PROTECT_REQ:
780     return Attribute::StackProtectReq;
781   case bitc::ATTR_KIND_STACK_PROTECT_STRONG:
782     return Attribute::StackProtectStrong;
783   case bitc::ATTR_KIND_STRUCT_RET:
784     return Attribute::StructRet;
785   case bitc::ATTR_KIND_SANITIZE_ADDRESS:
786     return Attribute::SanitizeAddress;
787   case bitc::ATTR_KIND_SANITIZE_THREAD:
788     return Attribute::SanitizeThread;
789   case bitc::ATTR_KIND_SANITIZE_MEMORY:
790     return Attribute::SanitizeMemory;
791   case bitc::ATTR_KIND_UW_TABLE:
792     return Attribute::UWTable;
793   case bitc::ATTR_KIND_Z_EXT:
794     return Attribute::ZExt;
795   }
796 }
797 
798 std::error_code BitcodeReader::parseAlignmentValue(uint64_t Exponent,
799                                                    unsigned &Alignment) {
800   // Note: Alignment in bitcode files is incremented by 1, so that zero
801   // can be used for default alignment.
802   if (Exponent > Value::MaxAlignmentExponent + 1)
803     return Error("Invalid alignment value");
804   Alignment = (1 << static_cast<unsigned>(Exponent)) >> 1;
805   return std::error_code();
806 }
807 
808 std::error_code BitcodeReader::ParseAttrKind(uint64_t Code,
809                                              Attribute::AttrKind *Kind) {
810   *Kind = GetAttrFromCode(Code);
811   if (*Kind == Attribute::None)
812     return Error(BitcodeError::CorruptedBitcode,
813                  "Unknown attribute kind (" + Twine(Code) + ")");
814   return std::error_code();
815 }
816 
817 std::error_code BitcodeReader::ParseAttributeGroupBlock() {
818   if (Stream.EnterSubBlock(bitc::PARAMATTR_GROUP_BLOCK_ID))
819     return Error("Invalid record");
820 
821   if (!MAttributeGroups.empty())
822     return Error("Invalid multiple blocks");
823 
824   SmallVector<uint64_t, 64> Record;
825 
826   // Read all the records.
827   while (1) {
828     BitstreamEntry Entry = Stream.advanceSkippingSubblocks();
829 
830     switch (Entry.Kind) {
831     case BitstreamEntry::SubBlock: // Handled for us already.
832     case BitstreamEntry::Error:
833       return Error("Malformed block");
834     case BitstreamEntry::EndBlock:
835       return std::error_code();
836     case BitstreamEntry::Record:
837       // The interesting case.
838       break;
839     }
840 
841     // Read a record.
842     Record.clear();
843     switch (Stream.readRecord(Entry.ID, Record)) {
844     default:  // Default behavior: ignore.
845       break;
846     case bitc::PARAMATTR_GRP_CODE_ENTRY: { // ENTRY: [grpid, idx, a0, a1, ...]
847       if (Record.size() < 3)
848         return Error("Invalid record");
849 
850       uint64_t GrpID = Record[0];
851       uint64_t Idx = Record[1]; // Index of the object this attribute refers to.
852 
853       AttrBuilder B;
854       for (unsigned i = 2, e = Record.size(); i != e; ++i) {
855         if (Record[i] == 0) {        // Enum attribute
856           Attribute::AttrKind Kind;
857           if (std::error_code EC = ParseAttrKind(Record[++i], &Kind))
858             return EC;
859 
860           B.addAttribute(Kind);
861         } else if (Record[i] == 1) { // Integer attribute
862           Attribute::AttrKind Kind;
863           if (std::error_code EC = ParseAttrKind(Record[++i], &Kind))
864             return EC;
865           if (Kind == Attribute::Alignment)
866             B.addAlignmentAttr(Record[++i]);
867           else if (Kind == Attribute::StackAlignment)
868             B.addStackAlignmentAttr(Record[++i]);
869           else if (Kind == Attribute::Dereferenceable)
870             B.addDereferenceableAttr(Record[++i]);
871         } else {                     // String attribute
872           assert((Record[i] == 3 || Record[i] == 4) &&
873                  "Invalid attribute group entry");
874           bool HasValue = (Record[i++] == 4);
875           SmallString<64> KindStr;
876           SmallString<64> ValStr;
877 
878           while (Record[i] != 0 && i != e)
879             KindStr += Record[i++];
880           assert(Record[i] == 0 && "Kind string not null terminated");
881 
882           if (HasValue) {
883             // Has a value associated with it.
884             ++i; // Skip the '0' that terminates the "kind" string.
885             while (Record[i] != 0 && i != e)
886               ValStr += Record[i++];
887             assert(Record[i] == 0 && "Value string not null terminated");
888           }
889 
890           B.addAttribute(KindStr.str(), ValStr.str());
891         }
892       }
893 
894       MAttributeGroups[GrpID] = AttributeSet::get(Context, Idx, B);
895       break;
896     }
897     }
898   }
899 }
900 
901 std::error_code BitcodeReader::ParseTypeTable() {
902   if (Stream.EnterSubBlock(bitc::TYPE_BLOCK_ID_NEW))
903     return Error("Invalid record");
904 
905   return ParseTypeTableBody();
906 }
907 
908 std::error_code BitcodeReader::ParseTypeTableBody() {
909   if (!TypeList.empty())
910     return Error("Invalid multiple blocks");
911 
912   SmallVector<uint64_t, 64> Record;
913   unsigned NumRecords = 0;
914 
915   SmallString<64> TypeName;
916 
917   // Read all the records for this type table.
918   while (1) {
919     BitstreamEntry Entry = Stream.advanceSkippingSubblocks();
920 
921     switch (Entry.Kind) {
922     case BitstreamEntry::SubBlock: // Handled for us already.
923     case BitstreamEntry::Error:
924       return Error("Malformed block");
925     case BitstreamEntry::EndBlock:
926       if (NumRecords != TypeList.size())
927         return Error("Malformed block");
928       return std::error_code();
929     case BitstreamEntry::Record:
930       // The interesting case.
931       break;
932     }
933 
934     // Read a record.
935     Record.clear();
936     Type *ResultTy = nullptr;
937     switch (Stream.readRecord(Entry.ID, Record)) {
938     default:
939       return Error("Invalid value");
940     case bitc::TYPE_CODE_NUMENTRY: // TYPE_CODE_NUMENTRY: [numentries]
941       // TYPE_CODE_NUMENTRY contains a count of the number of types in the
942       // type list.  This allows us to reserve space.
943       if (Record.size() < 1)
944         return Error("Invalid record");
945       TypeList.resize(Record[0]);
946       continue;
947     case bitc::TYPE_CODE_VOID:      // VOID
948       ResultTy = Type::getVoidTy(Context);
949       break;
950     case bitc::TYPE_CODE_HALF:     // HALF
951       ResultTy = Type::getHalfTy(Context);
952       break;
953     case bitc::TYPE_CODE_FLOAT:     // FLOAT
954       ResultTy = Type::getFloatTy(Context);
955       break;
956     case bitc::TYPE_CODE_DOUBLE:    // DOUBLE
957       ResultTy = Type::getDoubleTy(Context);
958       break;
959     case bitc::TYPE_CODE_X86_FP80:  // X86_FP80
960       ResultTy = Type::getX86_FP80Ty(Context);
961       break;
962     case bitc::TYPE_CODE_FP128:     // FP128
963       ResultTy = Type::getFP128Ty(Context);
964       break;
965     case bitc::TYPE_CODE_PPC_FP128: // PPC_FP128
966       ResultTy = Type::getPPC_FP128Ty(Context);
967       break;
968     case bitc::TYPE_CODE_LABEL:     // LABEL
969       ResultTy = Type::getLabelTy(Context);
970       break;
971     case bitc::TYPE_CODE_METADATA:  // METADATA
972       ResultTy = Type::getMetadataTy(Context);
973       break;
974     case bitc::TYPE_CODE_X86_MMX:   // X86_MMX
975       ResultTy = Type::getX86_MMXTy(Context);
976       break;
977     case bitc::TYPE_CODE_INTEGER: { // INTEGER: [width]
978       if (Record.size() < 1)
979         return Error("Invalid record");
980 
981       uint64_t NumBits = Record[0];
982       if (NumBits < IntegerType::MIN_INT_BITS ||
983           NumBits > IntegerType::MAX_INT_BITS)
984         return Error("Bitwidth for integer type out of range");
985       ResultTy = IntegerType::get(Context, NumBits);
986       break;
987     }
988     case bitc::TYPE_CODE_POINTER: { // POINTER: [pointee type] or
989                                     //          [pointee type, address space]
990       if (Record.size() < 1)
991         return Error("Invalid record");
992       unsigned AddressSpace = 0;
993       if (Record.size() == 2)
994         AddressSpace = Record[1];
995       ResultTy = getTypeByID(Record[0]);
996       if (!ResultTy)
997         return Error("Invalid type");
998       ResultTy = PointerType::get(ResultTy, AddressSpace);
999       break;
1000     }
1001     case bitc::TYPE_CODE_FUNCTION_OLD: {
1002       // FIXME: attrid is dead, remove it in LLVM 4.0
1003       // FUNCTION: [vararg, attrid, retty, paramty x N]
1004       if (Record.size() < 3)
1005         return Error("Invalid record");
1006       SmallVector<Type*, 8> ArgTys;
1007       for (unsigned i = 3, e = Record.size(); i != e; ++i) {
1008         if (Type *T = getTypeByID(Record[i]))
1009           ArgTys.push_back(T);
1010         else
1011           break;
1012       }
1013 
1014       ResultTy = getTypeByID(Record[2]);
1015       if (!ResultTy || ArgTys.size() < Record.size()-3)
1016         return Error("Invalid type");
1017 
1018       ResultTy = FunctionType::get(ResultTy, ArgTys, Record[0]);
1019       break;
1020     }
1021     case bitc::TYPE_CODE_FUNCTION: {
1022       // FUNCTION: [vararg, retty, paramty x N]
1023       if (Record.size() < 2)
1024         return Error("Invalid record");
1025       SmallVector<Type*, 8> ArgTys;
1026       for (unsigned i = 2, e = Record.size(); i != e; ++i) {
1027         if (Type *T = getTypeByID(Record[i]))
1028           ArgTys.push_back(T);
1029         else
1030           break;
1031       }
1032 
1033       ResultTy = getTypeByID(Record[1]);
1034       if (!ResultTy || ArgTys.size() < Record.size()-2)
1035         return Error("Invalid type");
1036 
1037       ResultTy = FunctionType::get(ResultTy, ArgTys, Record[0]);
1038       break;
1039     }
1040     case bitc::TYPE_CODE_STRUCT_ANON: {  // STRUCT: [ispacked, eltty x N]
1041       if (Record.size() < 1)
1042         return Error("Invalid record");
1043       SmallVector<Type*, 8> EltTys;
1044       for (unsigned i = 1, e = Record.size(); i != e; ++i) {
1045         if (Type *T = getTypeByID(Record[i]))
1046           EltTys.push_back(T);
1047         else
1048           break;
1049       }
1050       if (EltTys.size() != Record.size()-1)
1051         return Error("Invalid type");
1052       ResultTy = StructType::get(Context, EltTys, Record[0]);
1053       break;
1054     }
1055     case bitc::TYPE_CODE_STRUCT_NAME:   // STRUCT_NAME: [strchr x N]
1056       if (ConvertToString(Record, 0, TypeName))
1057         return Error("Invalid record");
1058       continue;
1059 
1060     case bitc::TYPE_CODE_STRUCT_NAMED: { // STRUCT: [ispacked, eltty x N]
1061       if (Record.size() < 1)
1062         return Error("Invalid record");
1063 
1064       if (NumRecords >= TypeList.size())
1065         return Error("Invalid TYPE table");
1066 
1067       // Check to see if this was forward referenced, if so fill in the temp.
1068       StructType *Res = cast_or_null<StructType>(TypeList[NumRecords]);
1069       if (Res) {
1070         Res->setName(TypeName);
1071         TypeList[NumRecords] = nullptr;
1072       } else  // Otherwise, create a new struct.
1073         Res = createIdentifiedStructType(Context, TypeName);
1074       TypeName.clear();
1075 
1076       SmallVector<Type*, 8> EltTys;
1077       for (unsigned i = 1, e = Record.size(); i != e; ++i) {
1078         if (Type *T = getTypeByID(Record[i]))
1079           EltTys.push_back(T);
1080         else
1081           break;
1082       }
1083       if (EltTys.size() != Record.size()-1)
1084         return Error("Invalid record");
1085       Res->setBody(EltTys, Record[0]);
1086       ResultTy = Res;
1087       break;
1088     }
1089     case bitc::TYPE_CODE_OPAQUE: {       // OPAQUE: []
1090       if (Record.size() != 1)
1091         return Error("Invalid record");
1092 
1093       if (NumRecords >= TypeList.size())
1094         return Error("Invalid TYPE table");
1095 
1096       // Check to see if this was forward referenced, if so fill in the temp.
1097       StructType *Res = cast_or_null<StructType>(TypeList[NumRecords]);
1098       if (Res) {
1099         Res->setName(TypeName);
1100         TypeList[NumRecords] = nullptr;
1101       } else  // Otherwise, create a new struct with no body.
1102         Res = createIdentifiedStructType(Context, TypeName);
1103       TypeName.clear();
1104       ResultTy = Res;
1105       break;
1106     }
1107     case bitc::TYPE_CODE_ARRAY:     // ARRAY: [numelts, eltty]
1108       if (Record.size() < 2)
1109         return Error("Invalid record");
1110       if ((ResultTy = getTypeByID(Record[1])))
1111         ResultTy = ArrayType::get(ResultTy, Record[0]);
1112       else
1113         return Error("Invalid type");
1114       break;
1115     case bitc::TYPE_CODE_VECTOR:    // VECTOR: [numelts, eltty]
1116       if (Record.size() < 2)
1117         return Error("Invalid record");
1118       if ((ResultTy = getTypeByID(Record[1])))
1119         ResultTy = VectorType::get(ResultTy, Record[0]);
1120       else
1121         return Error("Invalid type");
1122       break;
1123     }
1124 
1125     if (NumRecords >= TypeList.size())
1126       return Error("Invalid TYPE table");
1127     if (TypeList[NumRecords])
1128       return Error(
1129           "Invalid TYPE table: Only named structs can be forward referenced");
1130     assert(ResultTy && "Didn't read a type?");
1131     TypeList[NumRecords++] = ResultTy;
1132   }
1133 }
1134 
1135 std::error_code BitcodeReader::ParseValueSymbolTable() {
1136   if (Stream.EnterSubBlock(bitc::VALUE_SYMTAB_BLOCK_ID))
1137     return Error("Invalid record");
1138 
1139   SmallVector<uint64_t, 64> Record;
1140 
1141   Triple TT(TheModule->getTargetTriple());
1142 
1143   // Read all the records for this value table.
1144   SmallString<128> ValueName;
1145   while (1) {
1146     BitstreamEntry Entry = Stream.advanceSkippingSubblocks();
1147 
1148     switch (Entry.Kind) {
1149     case BitstreamEntry::SubBlock: // Handled for us already.
1150     case BitstreamEntry::Error:
1151       return Error("Malformed block");
1152     case BitstreamEntry::EndBlock:
1153       return std::error_code();
1154     case BitstreamEntry::Record:
1155       // The interesting case.
1156       break;
1157     }
1158 
1159     // Read a record.
1160     Record.clear();
1161     switch (Stream.readRecord(Entry.ID, Record)) {
1162     default:  // Default behavior: unknown type.
1163       break;
1164     case bitc::VST_CODE_ENTRY: {  // VST_ENTRY: [valueid, namechar x N]
1165       if (ConvertToString(Record, 1, ValueName))
1166         return Error("Invalid record");
1167       unsigned ValueID = Record[0];
1168       if (ValueID >= ValueList.size() || !ValueList[ValueID])
1169         return Error("Invalid record");
1170       Value *V = ValueList[ValueID];
1171 
1172       V->setName(StringRef(ValueName.data(), ValueName.size()));
1173       if (auto *GO = dyn_cast<GlobalObject>(V)) {
1174         if (GO->getComdat() == reinterpret_cast<Comdat *>(1)) {
1175           if (TT.isOSBinFormatMachO())
1176             GO->setComdat(nullptr);
1177           else
1178             GO->setComdat(TheModule->getOrInsertComdat(V->getName()));
1179         }
1180       }
1181       ValueName.clear();
1182       break;
1183     }
1184     case bitc::VST_CODE_BBENTRY: {
1185       if (ConvertToString(Record, 1, ValueName))
1186         return Error("Invalid record");
1187       BasicBlock *BB = getBasicBlock(Record[0]);
1188       if (!BB)
1189         return Error("Invalid record");
1190 
1191       BB->setName(StringRef(ValueName.data(), ValueName.size()));
1192       ValueName.clear();
1193       break;
1194     }
1195     }
1196   }
1197 }
1198 
1199 static int64_t unrotateSign(uint64_t U) { return U & 1 ? ~(U >> 1) : U >> 1; }
1200 
1201 std::error_code BitcodeReader::ParseMetadata() {
1202   unsigned NextMDValueNo = MDValueList.size();
1203 
1204   if (Stream.EnterSubBlock(bitc::METADATA_BLOCK_ID))
1205     return Error("Invalid record");
1206 
1207   SmallVector<uint64_t, 64> Record;
1208 
1209   auto getMD =
1210       [&](unsigned ID) -> Metadata *{ return MDValueList.getValueFwdRef(ID); };
1211   auto getMDOrNull = [&](unsigned ID) -> Metadata *{
1212     if (ID)
1213       return getMD(ID - 1);
1214     return nullptr;
1215   };
1216   auto getMDString = [&](unsigned ID) -> MDString *{
1217     // This requires that the ID is not really a forward reference.  In
1218     // particular, the MDString must already have been resolved.
1219     return cast_or_null<MDString>(getMDOrNull(ID));
1220   };
1221 
1222 #define GET_OR_DISTINCT(CLASS, DISTINCT, ARGS)                                 \
1223   (DISTINCT ? CLASS::getDistinct ARGS : CLASS::get ARGS)
1224 
1225   // Read all the records.
1226   while (1) {
1227     BitstreamEntry Entry = Stream.advanceSkippingSubblocks();
1228 
1229     switch (Entry.Kind) {
1230     case BitstreamEntry::SubBlock: // Handled for us already.
1231     case BitstreamEntry::Error:
1232       return Error("Malformed block");
1233     case BitstreamEntry::EndBlock:
1234       MDValueList.tryToResolveCycles();
1235       return std::error_code();
1236     case BitstreamEntry::Record:
1237       // The interesting case.
1238       break;
1239     }
1240 
1241     // Read a record.
1242     Record.clear();
1243     unsigned Code = Stream.readRecord(Entry.ID, Record);
1244     bool IsDistinct = false;
1245     switch (Code) {
1246     default:  // Default behavior: ignore.
1247       break;
1248     case bitc::METADATA_NAME: {
1249       // Read name of the named metadata.
1250       SmallString<8> Name(Record.begin(), Record.end());
1251       Record.clear();
1252       Code = Stream.ReadCode();
1253 
1254       // METADATA_NAME is always followed by METADATA_NAMED_NODE.
1255       unsigned NextBitCode = Stream.readRecord(Code, Record);
1256       assert(NextBitCode == bitc::METADATA_NAMED_NODE); (void)NextBitCode;
1257 
1258       // Read named metadata elements.
1259       unsigned Size = Record.size();
1260       NamedMDNode *NMD = TheModule->getOrInsertNamedMetadata(Name);
1261       for (unsigned i = 0; i != Size; ++i) {
1262         MDNode *MD = dyn_cast_or_null<MDNode>(MDValueList.getValueFwdRef(Record[i]));
1263         if (!MD)
1264           return Error("Invalid record");
1265         NMD->addOperand(MD);
1266       }
1267       break;
1268     }
1269     case bitc::METADATA_OLD_FN_NODE: {
1270       // FIXME: Remove in 4.0.
1271       // This is a LocalAsMetadata record, the only type of function-local
1272       // metadata.
1273       if (Record.size() % 2 == 1)
1274         return Error("Invalid record");
1275 
1276       // If this isn't a LocalAsMetadata record, we're dropping it.  This used
1277       // to be legal, but there's no upgrade path.
1278       auto dropRecord = [&] {
1279         MDValueList.AssignValue(MDNode::get(Context, None), NextMDValueNo++);
1280       };
1281       if (Record.size() != 2) {
1282         dropRecord();
1283         break;
1284       }
1285 
1286       Type *Ty = getTypeByID(Record[0]);
1287       if (Ty->isMetadataTy() || Ty->isVoidTy()) {
1288         dropRecord();
1289         break;
1290       }
1291 
1292       MDValueList.AssignValue(
1293           LocalAsMetadata::get(ValueList.getValueFwdRef(Record[1], Ty)),
1294           NextMDValueNo++);
1295       break;
1296     }
1297     case bitc::METADATA_OLD_NODE: {
1298       // FIXME: Remove in 4.0.
1299       if (Record.size() % 2 == 1)
1300         return Error("Invalid record");
1301 
1302       unsigned Size = Record.size();
1303       SmallVector<Metadata *, 8> Elts;
1304       for (unsigned i = 0; i != Size; i += 2) {
1305         Type *Ty = getTypeByID(Record[i]);
1306         if (!Ty)
1307           return Error("Invalid record");
1308         if (Ty->isMetadataTy())
1309           Elts.push_back(MDValueList.getValueFwdRef(Record[i+1]));
1310         else if (!Ty->isVoidTy()) {
1311           auto *MD =
1312               ValueAsMetadata::get(ValueList.getValueFwdRef(Record[i + 1], Ty));
1313           assert(isa<ConstantAsMetadata>(MD) &&
1314                  "Expected non-function-local metadata");
1315           Elts.push_back(MD);
1316         } else
1317           Elts.push_back(nullptr);
1318       }
1319       MDValueList.AssignValue(MDNode::get(Context, Elts), NextMDValueNo++);
1320       break;
1321     }
1322     case bitc::METADATA_VALUE: {
1323       if (Record.size() != 2)
1324         return Error("Invalid record");
1325 
1326       Type *Ty = getTypeByID(Record[0]);
1327       if (Ty->isMetadataTy() || Ty->isVoidTy())
1328         return Error("Invalid record");
1329 
1330       MDValueList.AssignValue(
1331           ValueAsMetadata::get(ValueList.getValueFwdRef(Record[1], Ty)),
1332           NextMDValueNo++);
1333       break;
1334     }
1335     case bitc::METADATA_DISTINCT_NODE:
1336       IsDistinct = true;
1337       // fallthrough...
1338     case bitc::METADATA_NODE: {
1339       SmallVector<Metadata *, 8> Elts;
1340       Elts.reserve(Record.size());
1341       for (unsigned ID : Record)
1342         Elts.push_back(ID ? MDValueList.getValueFwdRef(ID - 1) : nullptr);
1343       MDValueList.AssignValue(IsDistinct ? MDNode::getDistinct(Context, Elts)
1344                                          : MDNode::get(Context, Elts),
1345                               NextMDValueNo++);
1346       break;
1347     }
1348     case bitc::METADATA_LOCATION: {
1349       if (Record.size() != 5)
1350         return Error("Invalid record");
1351 
1352       auto get = Record[0] ? MDLocation::getDistinct : MDLocation::get;
1353       unsigned Line = Record[1];
1354       unsigned Column = Record[2];
1355       MDNode *Scope = cast<MDNode>(MDValueList.getValueFwdRef(Record[3]));
1356       Metadata *InlinedAt =
1357           Record[4] ? MDValueList.getValueFwdRef(Record[4] - 1) : nullptr;
1358       MDValueList.AssignValue(get(Context, Line, Column, Scope, InlinedAt),
1359                               NextMDValueNo++);
1360       break;
1361     }
1362     case bitc::METADATA_GENERIC_DEBUG: {
1363       if (Record.size() < 4)
1364         return Error("Invalid record");
1365 
1366       unsigned Tag = Record[1];
1367       unsigned Version = Record[2];
1368 
1369       if (Tag >= 1u << 16 || Version != 0)
1370         return Error("Invalid record");
1371 
1372       auto *Header = getMDString(Record[3]);
1373       SmallVector<Metadata *, 8> DwarfOps;
1374       for (unsigned I = 4, E = Record.size(); I != E; ++I)
1375         DwarfOps.push_back(Record[I] ? MDValueList.getValueFwdRef(Record[I] - 1)
1376                                      : nullptr);
1377       MDValueList.AssignValue(GET_OR_DISTINCT(GenericDebugNode, Record[0],
1378                                               (Context, Tag, Header, DwarfOps)),
1379                               NextMDValueNo++);
1380       break;
1381     }
1382     case bitc::METADATA_SUBRANGE: {
1383       if (Record.size() != 3)
1384         return Error("Invalid record");
1385 
1386       MDValueList.AssignValue(
1387           GET_OR_DISTINCT(MDSubrange, Record[0],
1388                           (Context, Record[1], unrotateSign(Record[2]))),
1389           NextMDValueNo++);
1390       break;
1391     }
1392     case bitc::METADATA_ENUMERATOR: {
1393       if (Record.size() != 3)
1394         return Error("Invalid record");
1395 
1396       MDValueList.AssignValue(GET_OR_DISTINCT(MDEnumerator, Record[0],
1397                                               (Context, unrotateSign(Record[1]),
1398                                                getMDString(Record[2]))),
1399                               NextMDValueNo++);
1400       break;
1401     }
1402     case bitc::METADATA_BASIC_TYPE: {
1403       if (Record.size() != 6)
1404         return Error("Invalid record");
1405 
1406       MDValueList.AssignValue(
1407           GET_OR_DISTINCT(MDBasicType, Record[0],
1408                           (Context, Record[1], getMDString(Record[2]),
1409                            Record[3], Record[4], Record[5])),
1410           NextMDValueNo++);
1411       break;
1412     }
1413     case bitc::METADATA_DERIVED_TYPE: {
1414       if (Record.size() != 12)
1415         return Error("Invalid record");
1416 
1417       MDValueList.AssignValue(
1418           GET_OR_DISTINCT(MDDerivedType, Record[0],
1419                           (Context, Record[1], getMDString(Record[2]),
1420                            getMDOrNull(Record[3]), Record[4],
1421                            getMDOrNull(Record[5]), getMDOrNull(Record[6]),
1422                            Record[7], Record[8], Record[9], Record[10],
1423                            getMDOrNull(Record[11]))),
1424           NextMDValueNo++);
1425       break;
1426     }
1427     case bitc::METADATA_COMPOSITE_TYPE: {
1428       if (Record.size() != 16)
1429         return Error("Invalid record");
1430 
1431       MDValueList.AssignValue(
1432           GET_OR_DISTINCT(MDCompositeType, Record[0],
1433                           (Context, Record[1], getMDString(Record[2]),
1434                            getMDOrNull(Record[3]), Record[4],
1435                            getMDOrNull(Record[5]), getMDOrNull(Record[6]),
1436                            Record[7], Record[8], Record[9], Record[10],
1437                            getMDOrNull(Record[11]), Record[12],
1438                            getMDOrNull(Record[13]), getMDOrNull(Record[14]),
1439                            getMDString(Record[15]))),
1440           NextMDValueNo++);
1441       break;
1442     }
1443     case bitc::METADATA_SUBROUTINE_TYPE: {
1444       if (Record.size() != 3)
1445         return Error("Invalid record");
1446 
1447       MDValueList.AssignValue(
1448           GET_OR_DISTINCT(MDSubroutineType, Record[0],
1449                           (Context, Record[1], getMDOrNull(Record[2]))),
1450           NextMDValueNo++);
1451       break;
1452     }
1453     case bitc::METADATA_FILE: {
1454       if (Record.size() != 3)
1455         return Error("Invalid record");
1456 
1457       MDValueList.AssignValue(
1458           GET_OR_DISTINCT(MDFile, Record[0], (Context, getMDString(Record[1]),
1459                                               getMDString(Record[2]))),
1460           NextMDValueNo++);
1461       break;
1462     }
1463     case bitc::METADATA_COMPILE_UNIT: {
1464       if (Record.size() != 14)
1465         return Error("Invalid record");
1466 
1467       MDValueList.AssignValue(
1468           GET_OR_DISTINCT(MDCompileUnit, Record[0],
1469                           (Context, Record[1], getMDOrNull(Record[2]),
1470                            getMDString(Record[3]), Record[4],
1471                            getMDString(Record[5]), Record[6],
1472                            getMDString(Record[7]), Record[8],
1473                            getMDOrNull(Record[9]), getMDOrNull(Record[10]),
1474                            getMDOrNull(Record[11]), getMDOrNull(Record[12]),
1475                            getMDOrNull(Record[13]))),
1476           NextMDValueNo++);
1477       break;
1478     }
1479     case bitc::METADATA_SUBPROGRAM: {
1480       if (Record.size() != 19)
1481         return Error("Invalid record");
1482 
1483       MDValueList.AssignValue(
1484           GET_OR_DISTINCT(
1485               MDSubprogram, Record[0],
1486               (Context, getMDOrNull(Record[1]), getMDString(Record[2]),
1487                getMDString(Record[3]), getMDOrNull(Record[4]), Record[5],
1488                getMDOrNull(Record[6]), Record[7], Record[8], Record[9],
1489                getMDOrNull(Record[10]), Record[11], Record[12], Record[13],
1490                Record[14], getMDOrNull(Record[15]), getMDOrNull(Record[16]),
1491                getMDOrNull(Record[17]), getMDOrNull(Record[18]))),
1492           NextMDValueNo++);
1493       break;
1494     }
1495     case bitc::METADATA_LEXICAL_BLOCK: {
1496       if (Record.size() != 5)
1497         return Error("Invalid record");
1498 
1499       MDValueList.AssignValue(
1500           GET_OR_DISTINCT(MDLexicalBlock, Record[0],
1501                           (Context, getMDOrNull(Record[1]),
1502                            getMDOrNull(Record[2]), Record[3], Record[4])),
1503           NextMDValueNo++);
1504       break;
1505     }
1506     case bitc::METADATA_LEXICAL_BLOCK_FILE: {
1507       if (Record.size() != 4)
1508         return Error("Invalid record");
1509 
1510       MDValueList.AssignValue(
1511           GET_OR_DISTINCT(MDLexicalBlockFile, Record[0],
1512                           (Context, getMDOrNull(Record[1]),
1513                            getMDOrNull(Record[2]), Record[3])),
1514           NextMDValueNo++);
1515       break;
1516     }
1517     case bitc::METADATA_NAMESPACE: {
1518       if (Record.size() != 5)
1519         return Error("Invalid record");
1520 
1521       MDValueList.AssignValue(
1522           GET_OR_DISTINCT(MDNamespace, Record[0],
1523                           (Context, getMDOrNull(Record[1]),
1524                            getMDOrNull(Record[2]), getMDString(Record[3]),
1525                            Record[4])),
1526           NextMDValueNo++);
1527       break;
1528     }
1529     case bitc::METADATA_TEMPLATE_TYPE: {
1530       if (Record.size() != 3)
1531         return Error("Invalid record");
1532 
1533       MDValueList.AssignValue(GET_OR_DISTINCT(MDTemplateTypeParameter,
1534                                               Record[0],
1535                                               (Context, getMDString(Record[1]),
1536                                                getMDOrNull(Record[2]))),
1537                               NextMDValueNo++);
1538       break;
1539     }
1540     case bitc::METADATA_TEMPLATE_VALUE: {
1541       if (Record.size() != 5)
1542         return Error("Invalid record");
1543 
1544       MDValueList.AssignValue(
1545           GET_OR_DISTINCT(MDTemplateValueParameter, Record[0],
1546                           (Context, Record[1], getMDString(Record[2]),
1547                            getMDOrNull(Record[3]), getMDOrNull(Record[4]))),
1548           NextMDValueNo++);
1549       break;
1550     }
1551     case bitc::METADATA_GLOBAL_VAR: {
1552       if (Record.size() != 11)
1553         return Error("Invalid record");
1554 
1555       MDValueList.AssignValue(
1556           GET_OR_DISTINCT(MDGlobalVariable, Record[0],
1557                           (Context, getMDOrNull(Record[1]),
1558                            getMDString(Record[2]), getMDString(Record[3]),
1559                            getMDOrNull(Record[4]), Record[5],
1560                            getMDOrNull(Record[6]), Record[7], Record[8],
1561                            getMDOrNull(Record[9]), getMDOrNull(Record[10]))),
1562           NextMDValueNo++);
1563       break;
1564     }
1565     case bitc::METADATA_LOCAL_VAR: {
1566       if (Record.size() != 10)
1567         return Error("Invalid record");
1568 
1569       MDValueList.AssignValue(
1570           GET_OR_DISTINCT(MDLocalVariable, Record[0],
1571                           (Context, Record[1], getMDOrNull(Record[2]),
1572                            getMDString(Record[3]), getMDOrNull(Record[4]),
1573                            Record[5], getMDOrNull(Record[6]), Record[7],
1574                            Record[8], getMDOrNull(Record[9]))),
1575           NextMDValueNo++);
1576       break;
1577     }
1578     case bitc::METADATA_EXPRESSION: {
1579       if (Record.size() < 1)
1580         return Error("Invalid record");
1581 
1582       MDValueList.AssignValue(
1583           GET_OR_DISTINCT(MDExpression, Record[0],
1584                           (Context, makeArrayRef(Record).slice(1))),
1585           NextMDValueNo++);
1586       break;
1587     }
1588     case bitc::METADATA_OBJC_PROPERTY: {
1589       if (Record.size() != 8)
1590         return Error("Invalid record");
1591 
1592       MDValueList.AssignValue(
1593           GET_OR_DISTINCT(MDObjCProperty, Record[0],
1594                           (Context, getMDString(Record[1]),
1595                            getMDOrNull(Record[2]), Record[3],
1596                            getMDString(Record[4]), getMDString(Record[5]),
1597                            Record[6], getMDOrNull(Record[7]))),
1598           NextMDValueNo++);
1599       break;
1600     }
1601     case bitc::METADATA_IMPORTED_ENTITY: {
1602       if (Record.size() != 6)
1603         return Error("Invalid record");
1604 
1605       MDValueList.AssignValue(
1606           GET_OR_DISTINCT(MDImportedEntity, Record[0],
1607                           (Context, Record[1], getMDOrNull(Record[2]),
1608                            getMDOrNull(Record[3]), Record[4],
1609                            getMDString(Record[5]))),
1610           NextMDValueNo++);
1611       break;
1612     }
1613     case bitc::METADATA_STRING: {
1614       std::string String(Record.begin(), Record.end());
1615       llvm::UpgradeMDStringConstant(String);
1616       Metadata *MD = MDString::get(Context, String);
1617       MDValueList.AssignValue(MD, NextMDValueNo++);
1618       break;
1619     }
1620     case bitc::METADATA_KIND: {
1621       if (Record.size() < 2)
1622         return Error("Invalid record");
1623 
1624       unsigned Kind = Record[0];
1625       SmallString<8> Name(Record.begin()+1, Record.end());
1626 
1627       unsigned NewKind = TheModule->getMDKindID(Name.str());
1628       if (!MDKindMap.insert(std::make_pair(Kind, NewKind)).second)
1629         return Error("Conflicting METADATA_KIND records");
1630       break;
1631     }
1632     }
1633   }
1634 #undef GET_OR_DISTINCT
1635 }
1636 
1637 /// decodeSignRotatedValue - Decode a signed value stored with the sign bit in
1638 /// the LSB for dense VBR encoding.
1639 uint64_t BitcodeReader::decodeSignRotatedValue(uint64_t V) {
1640   if ((V & 1) == 0)
1641     return V >> 1;
1642   if (V != 1)
1643     return -(V >> 1);
1644   // There is no such thing as -0 with integers.  "-0" really means MININT.
1645   return 1ULL << 63;
1646 }
1647 
1648 /// ResolveGlobalAndAliasInits - Resolve all of the initializers for global
1649 /// values and aliases that we can.
1650 std::error_code BitcodeReader::ResolveGlobalAndAliasInits() {
1651   std::vector<std::pair<GlobalVariable*, unsigned> > GlobalInitWorklist;
1652   std::vector<std::pair<GlobalAlias*, unsigned> > AliasInitWorklist;
1653   std::vector<std::pair<Function*, unsigned> > FunctionPrefixWorklist;
1654   std::vector<std::pair<Function*, unsigned> > FunctionPrologueWorklist;
1655 
1656   GlobalInitWorklist.swap(GlobalInits);
1657   AliasInitWorklist.swap(AliasInits);
1658   FunctionPrefixWorklist.swap(FunctionPrefixes);
1659   FunctionPrologueWorklist.swap(FunctionPrologues);
1660 
1661   while (!GlobalInitWorklist.empty()) {
1662     unsigned ValID = GlobalInitWorklist.back().second;
1663     if (ValID >= ValueList.size()) {
1664       // Not ready to resolve this yet, it requires something later in the file.
1665       GlobalInits.push_back(GlobalInitWorklist.back());
1666     } else {
1667       if (Constant *C = dyn_cast_or_null<Constant>(ValueList[ValID]))
1668         GlobalInitWorklist.back().first->setInitializer(C);
1669       else
1670         return Error("Expected a constant");
1671     }
1672     GlobalInitWorklist.pop_back();
1673   }
1674 
1675   while (!AliasInitWorklist.empty()) {
1676     unsigned ValID = AliasInitWorklist.back().second;
1677     if (ValID >= ValueList.size()) {
1678       AliasInits.push_back(AliasInitWorklist.back());
1679     } else {
1680       if (Constant *C = dyn_cast_or_null<Constant>(ValueList[ValID]))
1681         AliasInitWorklist.back().first->setAliasee(C);
1682       else
1683         return Error("Expected a constant");
1684     }
1685     AliasInitWorklist.pop_back();
1686   }
1687 
1688   while (!FunctionPrefixWorklist.empty()) {
1689     unsigned ValID = FunctionPrefixWorklist.back().second;
1690     if (ValID >= ValueList.size()) {
1691       FunctionPrefixes.push_back(FunctionPrefixWorklist.back());
1692     } else {
1693       if (Constant *C = dyn_cast_or_null<Constant>(ValueList[ValID]))
1694         FunctionPrefixWorklist.back().first->setPrefixData(C);
1695       else
1696         return Error("Expected a constant");
1697     }
1698     FunctionPrefixWorklist.pop_back();
1699   }
1700 
1701   while (!FunctionPrologueWorklist.empty()) {
1702     unsigned ValID = FunctionPrologueWorklist.back().second;
1703     if (ValID >= ValueList.size()) {
1704       FunctionPrologues.push_back(FunctionPrologueWorklist.back());
1705     } else {
1706       if (Constant *C = dyn_cast_or_null<Constant>(ValueList[ValID]))
1707         FunctionPrologueWorklist.back().first->setPrologueData(C);
1708       else
1709         return Error("Expected a constant");
1710     }
1711     FunctionPrologueWorklist.pop_back();
1712   }
1713 
1714   return std::error_code();
1715 }
1716 
1717 static APInt ReadWideAPInt(ArrayRef<uint64_t> Vals, unsigned TypeBits) {
1718   SmallVector<uint64_t, 8> Words(Vals.size());
1719   std::transform(Vals.begin(), Vals.end(), Words.begin(),
1720                  BitcodeReader::decodeSignRotatedValue);
1721 
1722   return APInt(TypeBits, Words);
1723 }
1724 
1725 std::error_code BitcodeReader::ParseConstants() {
1726   if (Stream.EnterSubBlock(bitc::CONSTANTS_BLOCK_ID))
1727     return Error("Invalid record");
1728 
1729   SmallVector<uint64_t, 64> Record;
1730 
1731   // Read all the records for this value table.
1732   Type *CurTy = Type::getInt32Ty(Context);
1733   unsigned NextCstNo = ValueList.size();
1734   while (1) {
1735     BitstreamEntry Entry = Stream.advanceSkippingSubblocks();
1736 
1737     switch (Entry.Kind) {
1738     case BitstreamEntry::SubBlock: // Handled for us already.
1739     case BitstreamEntry::Error:
1740       return Error("Malformed block");
1741     case BitstreamEntry::EndBlock:
1742       if (NextCstNo != ValueList.size())
1743         return Error("Invalid ronstant reference");
1744 
1745       // Once all the constants have been read, go through and resolve forward
1746       // references.
1747       ValueList.ResolveConstantForwardRefs();
1748       return std::error_code();
1749     case BitstreamEntry::Record:
1750       // The interesting case.
1751       break;
1752     }
1753 
1754     // Read a record.
1755     Record.clear();
1756     Value *V = nullptr;
1757     unsigned BitCode = Stream.readRecord(Entry.ID, Record);
1758     switch (BitCode) {
1759     default:  // Default behavior: unknown constant
1760     case bitc::CST_CODE_UNDEF:     // UNDEF
1761       V = UndefValue::get(CurTy);
1762       break;
1763     case bitc::CST_CODE_SETTYPE:   // SETTYPE: [typeid]
1764       if (Record.empty())
1765         return Error("Invalid record");
1766       if (Record[0] >= TypeList.size() || !TypeList[Record[0]])
1767         return Error("Invalid record");
1768       CurTy = TypeList[Record[0]];
1769       continue;  // Skip the ValueList manipulation.
1770     case bitc::CST_CODE_NULL:      // NULL
1771       V = Constant::getNullValue(CurTy);
1772       break;
1773     case bitc::CST_CODE_INTEGER:   // INTEGER: [intval]
1774       if (!CurTy->isIntegerTy() || Record.empty())
1775         return Error("Invalid record");
1776       V = ConstantInt::get(CurTy, decodeSignRotatedValue(Record[0]));
1777       break;
1778     case bitc::CST_CODE_WIDE_INTEGER: {// WIDE_INTEGER: [n x intval]
1779       if (!CurTy->isIntegerTy() || Record.empty())
1780         return Error("Invalid record");
1781 
1782       APInt VInt = ReadWideAPInt(Record,
1783                                  cast<IntegerType>(CurTy)->getBitWidth());
1784       V = ConstantInt::get(Context, VInt);
1785 
1786       break;
1787     }
1788     case bitc::CST_CODE_FLOAT: {    // FLOAT: [fpval]
1789       if (Record.empty())
1790         return Error("Invalid record");
1791       if (CurTy->isHalfTy())
1792         V = ConstantFP::get(Context, APFloat(APFloat::IEEEhalf,
1793                                              APInt(16, (uint16_t)Record[0])));
1794       else if (CurTy->isFloatTy())
1795         V = ConstantFP::get(Context, APFloat(APFloat::IEEEsingle,
1796                                              APInt(32, (uint32_t)Record[0])));
1797       else if (CurTy->isDoubleTy())
1798         V = ConstantFP::get(Context, APFloat(APFloat::IEEEdouble,
1799                                              APInt(64, Record[0])));
1800       else if (CurTy->isX86_FP80Ty()) {
1801         // Bits are not stored the same way as a normal i80 APInt, compensate.
1802         uint64_t Rearrange[2];
1803         Rearrange[0] = (Record[1] & 0xffffLL) | (Record[0] << 16);
1804         Rearrange[1] = Record[0] >> 48;
1805         V = ConstantFP::get(Context, APFloat(APFloat::x87DoubleExtended,
1806                                              APInt(80, Rearrange)));
1807       } else if (CurTy->isFP128Ty())
1808         V = ConstantFP::get(Context, APFloat(APFloat::IEEEquad,
1809                                              APInt(128, Record)));
1810       else if (CurTy->isPPC_FP128Ty())
1811         V = ConstantFP::get(Context, APFloat(APFloat::PPCDoubleDouble,
1812                                              APInt(128, Record)));
1813       else
1814         V = UndefValue::get(CurTy);
1815       break;
1816     }
1817 
1818     case bitc::CST_CODE_AGGREGATE: {// AGGREGATE: [n x value number]
1819       if (Record.empty())
1820         return Error("Invalid record");
1821 
1822       unsigned Size = Record.size();
1823       SmallVector<Constant*, 16> Elts;
1824 
1825       if (StructType *STy = dyn_cast<StructType>(CurTy)) {
1826         for (unsigned i = 0; i != Size; ++i)
1827           Elts.push_back(ValueList.getConstantFwdRef(Record[i],
1828                                                      STy->getElementType(i)));
1829         V = ConstantStruct::get(STy, Elts);
1830       } else if (ArrayType *ATy = dyn_cast<ArrayType>(CurTy)) {
1831         Type *EltTy = ATy->getElementType();
1832         for (unsigned i = 0; i != Size; ++i)
1833           Elts.push_back(ValueList.getConstantFwdRef(Record[i], EltTy));
1834         V = ConstantArray::get(ATy, Elts);
1835       } else if (VectorType *VTy = dyn_cast<VectorType>(CurTy)) {
1836         Type *EltTy = VTy->getElementType();
1837         for (unsigned i = 0; i != Size; ++i)
1838           Elts.push_back(ValueList.getConstantFwdRef(Record[i], EltTy));
1839         V = ConstantVector::get(Elts);
1840       } else {
1841         V = UndefValue::get(CurTy);
1842       }
1843       break;
1844     }
1845     case bitc::CST_CODE_STRING:    // STRING: [values]
1846     case bitc::CST_CODE_CSTRING: { // CSTRING: [values]
1847       if (Record.empty())
1848         return Error("Invalid record");
1849 
1850       SmallString<16> Elts(Record.begin(), Record.end());
1851       V = ConstantDataArray::getString(Context, Elts,
1852                                        BitCode == bitc::CST_CODE_CSTRING);
1853       break;
1854     }
1855     case bitc::CST_CODE_DATA: {// DATA: [n x value]
1856       if (Record.empty())
1857         return Error("Invalid record");
1858 
1859       Type *EltTy = cast<SequentialType>(CurTy)->getElementType();
1860       unsigned Size = Record.size();
1861 
1862       if (EltTy->isIntegerTy(8)) {
1863         SmallVector<uint8_t, 16> Elts(Record.begin(), Record.end());
1864         if (isa<VectorType>(CurTy))
1865           V = ConstantDataVector::get(Context, Elts);
1866         else
1867           V = ConstantDataArray::get(Context, Elts);
1868       } else if (EltTy->isIntegerTy(16)) {
1869         SmallVector<uint16_t, 16> Elts(Record.begin(), Record.end());
1870         if (isa<VectorType>(CurTy))
1871           V = ConstantDataVector::get(Context, Elts);
1872         else
1873           V = ConstantDataArray::get(Context, Elts);
1874       } else if (EltTy->isIntegerTy(32)) {
1875         SmallVector<uint32_t, 16> Elts(Record.begin(), Record.end());
1876         if (isa<VectorType>(CurTy))
1877           V = ConstantDataVector::get(Context, Elts);
1878         else
1879           V = ConstantDataArray::get(Context, Elts);
1880       } else if (EltTy->isIntegerTy(64)) {
1881         SmallVector<uint64_t, 16> Elts(Record.begin(), Record.end());
1882         if (isa<VectorType>(CurTy))
1883           V = ConstantDataVector::get(Context, Elts);
1884         else
1885           V = ConstantDataArray::get(Context, Elts);
1886       } else if (EltTy->isFloatTy()) {
1887         SmallVector<float, 16> Elts(Size);
1888         std::transform(Record.begin(), Record.end(), Elts.begin(), BitsToFloat);
1889         if (isa<VectorType>(CurTy))
1890           V = ConstantDataVector::get(Context, Elts);
1891         else
1892           V = ConstantDataArray::get(Context, Elts);
1893       } else if (EltTy->isDoubleTy()) {
1894         SmallVector<double, 16> Elts(Size);
1895         std::transform(Record.begin(), Record.end(), Elts.begin(),
1896                        BitsToDouble);
1897         if (isa<VectorType>(CurTy))
1898           V = ConstantDataVector::get(Context, Elts);
1899         else
1900           V = ConstantDataArray::get(Context, Elts);
1901       } else {
1902         return Error("Invalid type for value");
1903       }
1904       break;
1905     }
1906 
1907     case bitc::CST_CODE_CE_BINOP: {  // CE_BINOP: [opcode, opval, opval]
1908       if (Record.size() < 3)
1909         return Error("Invalid record");
1910       int Opc = GetDecodedBinaryOpcode(Record[0], CurTy);
1911       if (Opc < 0) {
1912         V = UndefValue::get(CurTy);  // Unknown binop.
1913       } else {
1914         Constant *LHS = ValueList.getConstantFwdRef(Record[1], CurTy);
1915         Constant *RHS = ValueList.getConstantFwdRef(Record[2], CurTy);
1916         unsigned Flags = 0;
1917         if (Record.size() >= 4) {
1918           if (Opc == Instruction::Add ||
1919               Opc == Instruction::Sub ||
1920               Opc == Instruction::Mul ||
1921               Opc == Instruction::Shl) {
1922             if (Record[3] & (1 << bitc::OBO_NO_SIGNED_WRAP))
1923               Flags |= OverflowingBinaryOperator::NoSignedWrap;
1924             if (Record[3] & (1 << bitc::OBO_NO_UNSIGNED_WRAP))
1925               Flags |= OverflowingBinaryOperator::NoUnsignedWrap;
1926           } else if (Opc == Instruction::SDiv ||
1927                      Opc == Instruction::UDiv ||
1928                      Opc == Instruction::LShr ||
1929                      Opc == Instruction::AShr) {
1930             if (Record[3] & (1 << bitc::PEO_EXACT))
1931               Flags |= SDivOperator::IsExact;
1932           }
1933         }
1934         V = ConstantExpr::get(Opc, LHS, RHS, Flags);
1935       }
1936       break;
1937     }
1938     case bitc::CST_CODE_CE_CAST: {  // CE_CAST: [opcode, opty, opval]
1939       if (Record.size() < 3)
1940         return Error("Invalid record");
1941       int Opc = GetDecodedCastOpcode(Record[0]);
1942       if (Opc < 0) {
1943         V = UndefValue::get(CurTy);  // Unknown cast.
1944       } else {
1945         Type *OpTy = getTypeByID(Record[1]);
1946         if (!OpTy)
1947           return Error("Invalid record");
1948         Constant *Op = ValueList.getConstantFwdRef(Record[2], OpTy);
1949         V = UpgradeBitCastExpr(Opc, Op, CurTy);
1950         if (!V) V = ConstantExpr::getCast(Opc, Op, CurTy);
1951       }
1952       break;
1953     }
1954     case bitc::CST_CODE_CE_INBOUNDS_GEP:
1955     case bitc::CST_CODE_CE_GEP: {  // CE_GEP:        [n x operands]
1956       if (Record.size() & 1)
1957         return Error("Invalid record");
1958       SmallVector<Constant*, 16> Elts;
1959       for (unsigned i = 0, e = Record.size(); i != e; i += 2) {
1960         Type *ElTy = getTypeByID(Record[i]);
1961         if (!ElTy)
1962           return Error("Invalid record");
1963         Elts.push_back(ValueList.getConstantFwdRef(Record[i+1], ElTy));
1964       }
1965       ArrayRef<Constant *> Indices(Elts.begin() + 1, Elts.end());
1966       V = ConstantExpr::getGetElementPtr(Elts[0], Indices,
1967                                          BitCode ==
1968                                            bitc::CST_CODE_CE_INBOUNDS_GEP);
1969       break;
1970     }
1971     case bitc::CST_CODE_CE_SELECT: {  // CE_SELECT: [opval#, opval#, opval#]
1972       if (Record.size() < 3)
1973         return Error("Invalid record");
1974 
1975       Type *SelectorTy = Type::getInt1Ty(Context);
1976 
1977       // If CurTy is a vector of length n, then Record[0] must be a <n x i1>
1978       // vector. Otherwise, it must be a single bit.
1979       if (VectorType *VTy = dyn_cast<VectorType>(CurTy))
1980         SelectorTy = VectorType::get(Type::getInt1Ty(Context),
1981                                      VTy->getNumElements());
1982 
1983       V = ConstantExpr::getSelect(ValueList.getConstantFwdRef(Record[0],
1984                                                               SelectorTy),
1985                                   ValueList.getConstantFwdRef(Record[1],CurTy),
1986                                   ValueList.getConstantFwdRef(Record[2],CurTy));
1987       break;
1988     }
1989     case bitc::CST_CODE_CE_EXTRACTELT
1990         : { // CE_EXTRACTELT: [opty, opval, opty, opval]
1991       if (Record.size() < 3)
1992         return Error("Invalid record");
1993       VectorType *OpTy =
1994         dyn_cast_or_null<VectorType>(getTypeByID(Record[0]));
1995       if (!OpTy)
1996         return Error("Invalid record");
1997       Constant *Op0 = ValueList.getConstantFwdRef(Record[1], OpTy);
1998       Constant *Op1 = nullptr;
1999       if (Record.size() == 4) {
2000         Type *IdxTy = getTypeByID(Record[2]);
2001         if (!IdxTy)
2002           return Error("Invalid record");
2003         Op1 = ValueList.getConstantFwdRef(Record[3], IdxTy);
2004       } else // TODO: Remove with llvm 4.0
2005         Op1 = ValueList.getConstantFwdRef(Record[2], Type::getInt32Ty(Context));
2006       if (!Op1)
2007         return Error("Invalid record");
2008       V = ConstantExpr::getExtractElement(Op0, Op1);
2009       break;
2010     }
2011     case bitc::CST_CODE_CE_INSERTELT
2012         : { // CE_INSERTELT: [opval, opval, opty, opval]
2013       VectorType *OpTy = dyn_cast<VectorType>(CurTy);
2014       if (Record.size() < 3 || !OpTy)
2015         return Error("Invalid record");
2016       Constant *Op0 = ValueList.getConstantFwdRef(Record[0], OpTy);
2017       Constant *Op1 = ValueList.getConstantFwdRef(Record[1],
2018                                                   OpTy->getElementType());
2019       Constant *Op2 = nullptr;
2020       if (Record.size() == 4) {
2021         Type *IdxTy = getTypeByID(Record[2]);
2022         if (!IdxTy)
2023           return Error("Invalid record");
2024         Op2 = ValueList.getConstantFwdRef(Record[3], IdxTy);
2025       } else // TODO: Remove with llvm 4.0
2026         Op2 = ValueList.getConstantFwdRef(Record[2], Type::getInt32Ty(Context));
2027       if (!Op2)
2028         return Error("Invalid record");
2029       V = ConstantExpr::getInsertElement(Op0, Op1, Op2);
2030       break;
2031     }
2032     case bitc::CST_CODE_CE_SHUFFLEVEC: { // CE_SHUFFLEVEC: [opval, opval, opval]
2033       VectorType *OpTy = dyn_cast<VectorType>(CurTy);
2034       if (Record.size() < 3 || !OpTy)
2035         return Error("Invalid record");
2036       Constant *Op0 = ValueList.getConstantFwdRef(Record[0], OpTy);
2037       Constant *Op1 = ValueList.getConstantFwdRef(Record[1], OpTy);
2038       Type *ShufTy = VectorType::get(Type::getInt32Ty(Context),
2039                                                  OpTy->getNumElements());
2040       Constant *Op2 = ValueList.getConstantFwdRef(Record[2], ShufTy);
2041       V = ConstantExpr::getShuffleVector(Op0, Op1, Op2);
2042       break;
2043     }
2044     case bitc::CST_CODE_CE_SHUFVEC_EX: { // [opty, opval, opval, opval]
2045       VectorType *RTy = dyn_cast<VectorType>(CurTy);
2046       VectorType *OpTy =
2047         dyn_cast_or_null<VectorType>(getTypeByID(Record[0]));
2048       if (Record.size() < 4 || !RTy || !OpTy)
2049         return Error("Invalid record");
2050       Constant *Op0 = ValueList.getConstantFwdRef(Record[1], OpTy);
2051       Constant *Op1 = ValueList.getConstantFwdRef(Record[2], OpTy);
2052       Type *ShufTy = VectorType::get(Type::getInt32Ty(Context),
2053                                                  RTy->getNumElements());
2054       Constant *Op2 = ValueList.getConstantFwdRef(Record[3], ShufTy);
2055       V = ConstantExpr::getShuffleVector(Op0, Op1, Op2);
2056       break;
2057     }
2058     case bitc::CST_CODE_CE_CMP: {     // CE_CMP: [opty, opval, opval, pred]
2059       if (Record.size() < 4)
2060         return Error("Invalid record");
2061       Type *OpTy = getTypeByID(Record[0]);
2062       if (!OpTy)
2063         return Error("Invalid record");
2064       Constant *Op0 = ValueList.getConstantFwdRef(Record[1], OpTy);
2065       Constant *Op1 = ValueList.getConstantFwdRef(Record[2], OpTy);
2066 
2067       if (OpTy->isFPOrFPVectorTy())
2068         V = ConstantExpr::getFCmp(Record[3], Op0, Op1);
2069       else
2070         V = ConstantExpr::getICmp(Record[3], Op0, Op1);
2071       break;
2072     }
2073     // This maintains backward compatibility, pre-asm dialect keywords.
2074     // FIXME: Remove with the 4.0 release.
2075     case bitc::CST_CODE_INLINEASM_OLD: {
2076       if (Record.size() < 2)
2077         return Error("Invalid record");
2078       std::string AsmStr, ConstrStr;
2079       bool HasSideEffects = Record[0] & 1;
2080       bool IsAlignStack = Record[0] >> 1;
2081       unsigned AsmStrSize = Record[1];
2082       if (2+AsmStrSize >= Record.size())
2083         return Error("Invalid record");
2084       unsigned ConstStrSize = Record[2+AsmStrSize];
2085       if (3+AsmStrSize+ConstStrSize > Record.size())
2086         return Error("Invalid record");
2087 
2088       for (unsigned i = 0; i != AsmStrSize; ++i)
2089         AsmStr += (char)Record[2+i];
2090       for (unsigned i = 0; i != ConstStrSize; ++i)
2091         ConstrStr += (char)Record[3+AsmStrSize+i];
2092       PointerType *PTy = cast<PointerType>(CurTy);
2093       V = InlineAsm::get(cast<FunctionType>(PTy->getElementType()),
2094                          AsmStr, ConstrStr, HasSideEffects, IsAlignStack);
2095       break;
2096     }
2097     // This version adds support for the asm dialect keywords (e.g.,
2098     // inteldialect).
2099     case bitc::CST_CODE_INLINEASM: {
2100       if (Record.size() < 2)
2101         return Error("Invalid record");
2102       std::string AsmStr, ConstrStr;
2103       bool HasSideEffects = Record[0] & 1;
2104       bool IsAlignStack = (Record[0] >> 1) & 1;
2105       unsigned AsmDialect = Record[0] >> 2;
2106       unsigned AsmStrSize = Record[1];
2107       if (2+AsmStrSize >= Record.size())
2108         return Error("Invalid record");
2109       unsigned ConstStrSize = Record[2+AsmStrSize];
2110       if (3+AsmStrSize+ConstStrSize > Record.size())
2111         return Error("Invalid record");
2112 
2113       for (unsigned i = 0; i != AsmStrSize; ++i)
2114         AsmStr += (char)Record[2+i];
2115       for (unsigned i = 0; i != ConstStrSize; ++i)
2116         ConstrStr += (char)Record[3+AsmStrSize+i];
2117       PointerType *PTy = cast<PointerType>(CurTy);
2118       V = InlineAsm::get(cast<FunctionType>(PTy->getElementType()),
2119                          AsmStr, ConstrStr, HasSideEffects, IsAlignStack,
2120                          InlineAsm::AsmDialect(AsmDialect));
2121       break;
2122     }
2123     case bitc::CST_CODE_BLOCKADDRESS:{
2124       if (Record.size() < 3)
2125         return Error("Invalid record");
2126       Type *FnTy = getTypeByID(Record[0]);
2127       if (!FnTy)
2128         return Error("Invalid record");
2129       Function *Fn =
2130         dyn_cast_or_null<Function>(ValueList.getConstantFwdRef(Record[1],FnTy));
2131       if (!Fn)
2132         return Error("Invalid record");
2133 
2134       // Don't let Fn get dematerialized.
2135       BlockAddressesTaken.insert(Fn);
2136 
2137       // If the function is already parsed we can insert the block address right
2138       // away.
2139       BasicBlock *BB;
2140       unsigned BBID = Record[2];
2141       if (!BBID)
2142         // Invalid reference to entry block.
2143         return Error("Invalid ID");
2144       if (!Fn->empty()) {
2145         Function::iterator BBI = Fn->begin(), BBE = Fn->end();
2146         for (size_t I = 0, E = BBID; I != E; ++I) {
2147           if (BBI == BBE)
2148             return Error("Invalid ID");
2149           ++BBI;
2150         }
2151         BB = BBI;
2152       } else {
2153         // Otherwise insert a placeholder and remember it so it can be inserted
2154         // when the function is parsed.
2155         auto &FwdBBs = BasicBlockFwdRefs[Fn];
2156         if (FwdBBs.empty())
2157           BasicBlockFwdRefQueue.push_back(Fn);
2158         if (FwdBBs.size() < BBID + 1)
2159           FwdBBs.resize(BBID + 1);
2160         if (!FwdBBs[BBID])
2161           FwdBBs[BBID] = BasicBlock::Create(Context);
2162         BB = FwdBBs[BBID];
2163       }
2164       V = BlockAddress::get(Fn, BB);
2165       break;
2166     }
2167     }
2168 
2169     ValueList.AssignValue(V, NextCstNo);
2170     ++NextCstNo;
2171   }
2172 }
2173 
2174 std::error_code BitcodeReader::ParseUseLists() {
2175   if (Stream.EnterSubBlock(bitc::USELIST_BLOCK_ID))
2176     return Error("Invalid record");
2177 
2178   // Read all the records.
2179   SmallVector<uint64_t, 64> Record;
2180   while (1) {
2181     BitstreamEntry Entry = Stream.advanceSkippingSubblocks();
2182 
2183     switch (Entry.Kind) {
2184     case BitstreamEntry::SubBlock: // Handled for us already.
2185     case BitstreamEntry::Error:
2186       return Error("Malformed block");
2187     case BitstreamEntry::EndBlock:
2188       return std::error_code();
2189     case BitstreamEntry::Record:
2190       // The interesting case.
2191       break;
2192     }
2193 
2194     // Read a use list record.
2195     Record.clear();
2196     bool IsBB = false;
2197     switch (Stream.readRecord(Entry.ID, Record)) {
2198     default:  // Default behavior: unknown type.
2199       break;
2200     case bitc::USELIST_CODE_BB:
2201       IsBB = true;
2202       // fallthrough
2203     case bitc::USELIST_CODE_DEFAULT: {
2204       unsigned RecordLength = Record.size();
2205       if (RecordLength < 3)
2206         // Records should have at least an ID and two indexes.
2207         return Error("Invalid record");
2208       unsigned ID = Record.back();
2209       Record.pop_back();
2210 
2211       Value *V;
2212       if (IsBB) {
2213         assert(ID < FunctionBBs.size() && "Basic block not found");
2214         V = FunctionBBs[ID];
2215       } else
2216         V = ValueList[ID];
2217       unsigned NumUses = 0;
2218       SmallDenseMap<const Use *, unsigned, 16> Order;
2219       for (const Use &U : V->uses()) {
2220         if (++NumUses > Record.size())
2221           break;
2222         Order[&U] = Record[NumUses - 1];
2223       }
2224       if (Order.size() != Record.size() || NumUses > Record.size())
2225         // Mismatches can happen if the functions are being materialized lazily
2226         // (out-of-order), or a value has been upgraded.
2227         break;
2228 
2229       V->sortUseList([&](const Use &L, const Use &R) {
2230         return Order.lookup(&L) < Order.lookup(&R);
2231       });
2232       break;
2233     }
2234     }
2235   }
2236 }
2237 
2238 /// RememberAndSkipFunctionBody - When we see the block for a function body,
2239 /// remember where it is and then skip it.  This lets us lazily deserialize the
2240 /// functions.
2241 std::error_code BitcodeReader::RememberAndSkipFunctionBody() {
2242   // Get the function we are talking about.
2243   if (FunctionsWithBodies.empty())
2244     return Error("Insufficient function protos");
2245 
2246   Function *Fn = FunctionsWithBodies.back();
2247   FunctionsWithBodies.pop_back();
2248 
2249   // Save the current stream state.
2250   uint64_t CurBit = Stream.GetCurrentBitNo();
2251   DeferredFunctionInfo[Fn] = CurBit;
2252 
2253   // Skip over the function block for now.
2254   if (Stream.SkipBlock())
2255     return Error("Invalid record");
2256   return std::error_code();
2257 }
2258 
2259 std::error_code BitcodeReader::GlobalCleanup() {
2260   // Patch the initializers for globals and aliases up.
2261   ResolveGlobalAndAliasInits();
2262   if (!GlobalInits.empty() || !AliasInits.empty())
2263     return Error("Malformed global initializer set");
2264 
2265   // Look for intrinsic functions which need to be upgraded at some point
2266   for (Module::iterator FI = TheModule->begin(), FE = TheModule->end();
2267        FI != FE; ++FI) {
2268     Function *NewFn;
2269     if (UpgradeIntrinsicFunction(FI, NewFn))
2270       UpgradedIntrinsics.push_back(std::make_pair(FI, NewFn));
2271   }
2272 
2273   // Look for global variables which need to be renamed.
2274   for (Module::global_iterator
2275          GI = TheModule->global_begin(), GE = TheModule->global_end();
2276        GI != GE;) {
2277     GlobalVariable *GV = GI++;
2278     UpgradeGlobalVariable(GV);
2279   }
2280 
2281   // Force deallocation of memory for these vectors to favor the client that
2282   // want lazy deserialization.
2283   std::vector<std::pair<GlobalVariable*, unsigned> >().swap(GlobalInits);
2284   std::vector<std::pair<GlobalAlias*, unsigned> >().swap(AliasInits);
2285   return std::error_code();
2286 }
2287 
2288 std::error_code BitcodeReader::ParseModule(bool Resume) {
2289   if (Resume)
2290     Stream.JumpToBit(NextUnreadBit);
2291   else if (Stream.EnterSubBlock(bitc::MODULE_BLOCK_ID))
2292     return Error("Invalid record");
2293 
2294   SmallVector<uint64_t, 64> Record;
2295   std::vector<std::string> SectionTable;
2296   std::vector<std::string> GCTable;
2297 
2298   // Read all the records for this module.
2299   while (1) {
2300     BitstreamEntry Entry = Stream.advance();
2301 
2302     switch (Entry.Kind) {
2303     case BitstreamEntry::Error:
2304       return Error("Malformed block");
2305     case BitstreamEntry::EndBlock:
2306       return GlobalCleanup();
2307 
2308     case BitstreamEntry::SubBlock:
2309       switch (Entry.ID) {
2310       default:  // Skip unknown content.
2311         if (Stream.SkipBlock())
2312           return Error("Invalid record");
2313         break;
2314       case bitc::BLOCKINFO_BLOCK_ID:
2315         if (Stream.ReadBlockInfoBlock())
2316           return Error("Malformed block");
2317         break;
2318       case bitc::PARAMATTR_BLOCK_ID:
2319         if (std::error_code EC = ParseAttributeBlock())
2320           return EC;
2321         break;
2322       case bitc::PARAMATTR_GROUP_BLOCK_ID:
2323         if (std::error_code EC = ParseAttributeGroupBlock())
2324           return EC;
2325         break;
2326       case bitc::TYPE_BLOCK_ID_NEW:
2327         if (std::error_code EC = ParseTypeTable())
2328           return EC;
2329         break;
2330       case bitc::VALUE_SYMTAB_BLOCK_ID:
2331         if (std::error_code EC = ParseValueSymbolTable())
2332           return EC;
2333         SeenValueSymbolTable = true;
2334         break;
2335       case bitc::CONSTANTS_BLOCK_ID:
2336         if (std::error_code EC = ParseConstants())
2337           return EC;
2338         if (std::error_code EC = ResolveGlobalAndAliasInits())
2339           return EC;
2340         break;
2341       case bitc::METADATA_BLOCK_ID:
2342         if (std::error_code EC = ParseMetadata())
2343           return EC;
2344         break;
2345       case bitc::FUNCTION_BLOCK_ID:
2346         // If this is the first function body we've seen, reverse the
2347         // FunctionsWithBodies list.
2348         if (!SeenFirstFunctionBody) {
2349           std::reverse(FunctionsWithBodies.begin(), FunctionsWithBodies.end());
2350           if (std::error_code EC = GlobalCleanup())
2351             return EC;
2352           SeenFirstFunctionBody = true;
2353         }
2354 
2355         if (std::error_code EC = RememberAndSkipFunctionBody())
2356           return EC;
2357         // For streaming bitcode, suspend parsing when we reach the function
2358         // bodies. Subsequent materialization calls will resume it when
2359         // necessary. For streaming, the function bodies must be at the end of
2360         // the bitcode. If the bitcode file is old, the symbol table will be
2361         // at the end instead and will not have been seen yet. In this case,
2362         // just finish the parse now.
2363         if (LazyStreamer && SeenValueSymbolTable) {
2364           NextUnreadBit = Stream.GetCurrentBitNo();
2365           return std::error_code();
2366         }
2367         break;
2368       case bitc::USELIST_BLOCK_ID:
2369         if (std::error_code EC = ParseUseLists())
2370           return EC;
2371         break;
2372       }
2373       continue;
2374 
2375     case BitstreamEntry::Record:
2376       // The interesting case.
2377       break;
2378     }
2379 
2380 
2381     // Read a record.
2382     switch (Stream.readRecord(Entry.ID, Record)) {
2383     default: break;  // Default behavior, ignore unknown content.
2384     case bitc::MODULE_CODE_VERSION: {  // VERSION: [version#]
2385       if (Record.size() < 1)
2386         return Error("Invalid record");
2387       // Only version #0 and #1 are supported so far.
2388       unsigned module_version = Record[0];
2389       switch (module_version) {
2390         default:
2391           return Error("Invalid value");
2392         case 0:
2393           UseRelativeIDs = false;
2394           break;
2395         case 1:
2396           UseRelativeIDs = true;
2397           break;
2398       }
2399       break;
2400     }
2401     case bitc::MODULE_CODE_TRIPLE: {  // TRIPLE: [strchr x N]
2402       std::string S;
2403       if (ConvertToString(Record, 0, S))
2404         return Error("Invalid record");
2405       TheModule->setTargetTriple(S);
2406       break;
2407     }
2408     case bitc::MODULE_CODE_DATALAYOUT: {  // DATALAYOUT: [strchr x N]
2409       std::string S;
2410       if (ConvertToString(Record, 0, S))
2411         return Error("Invalid record");
2412       TheModule->setDataLayout(S);
2413       break;
2414     }
2415     case bitc::MODULE_CODE_ASM: {  // ASM: [strchr x N]
2416       std::string S;
2417       if (ConvertToString(Record, 0, S))
2418         return Error("Invalid record");
2419       TheModule->setModuleInlineAsm(S);
2420       break;
2421     }
2422     case bitc::MODULE_CODE_DEPLIB: {  // DEPLIB: [strchr x N]
2423       // FIXME: Remove in 4.0.
2424       std::string S;
2425       if (ConvertToString(Record, 0, S))
2426         return Error("Invalid record");
2427       // Ignore value.
2428       break;
2429     }
2430     case bitc::MODULE_CODE_SECTIONNAME: {  // SECTIONNAME: [strchr x N]
2431       std::string S;
2432       if (ConvertToString(Record, 0, S))
2433         return Error("Invalid record");
2434       SectionTable.push_back(S);
2435       break;
2436     }
2437     case bitc::MODULE_CODE_GCNAME: {  // SECTIONNAME: [strchr x N]
2438       std::string S;
2439       if (ConvertToString(Record, 0, S))
2440         return Error("Invalid record");
2441       GCTable.push_back(S);
2442       break;
2443     }
2444     case bitc::MODULE_CODE_COMDAT: { // COMDAT: [selection_kind, name]
2445       if (Record.size() < 2)
2446         return Error("Invalid record");
2447       Comdat::SelectionKind SK = getDecodedComdatSelectionKind(Record[0]);
2448       unsigned ComdatNameSize = Record[1];
2449       std::string ComdatName;
2450       ComdatName.reserve(ComdatNameSize);
2451       for (unsigned i = 0; i != ComdatNameSize; ++i)
2452         ComdatName += (char)Record[2 + i];
2453       Comdat *C = TheModule->getOrInsertComdat(ComdatName);
2454       C->setSelectionKind(SK);
2455       ComdatList.push_back(C);
2456       break;
2457     }
2458     // GLOBALVAR: [pointer type, isconst, initid,
2459     //             linkage, alignment, section, visibility, threadlocal,
2460     //             unnamed_addr, externally_initialized, dllstorageclass,
2461     //             comdat]
2462     case bitc::MODULE_CODE_GLOBALVAR: {
2463       if (Record.size() < 6)
2464         return Error("Invalid record");
2465       Type *Ty = getTypeByID(Record[0]);
2466       if (!Ty)
2467         return Error("Invalid record");
2468       if (!Ty->isPointerTy())
2469         return Error("Invalid type for value");
2470       unsigned AddressSpace = cast<PointerType>(Ty)->getAddressSpace();
2471       Ty = cast<PointerType>(Ty)->getElementType();
2472 
2473       bool isConstant = Record[1];
2474       uint64_t RawLinkage = Record[3];
2475       GlobalValue::LinkageTypes Linkage = getDecodedLinkage(RawLinkage);
2476       unsigned Alignment;
2477       if (std::error_code EC = parseAlignmentValue(Record[4], Alignment))
2478         return EC;
2479       std::string Section;
2480       if (Record[5]) {
2481         if (Record[5]-1 >= SectionTable.size())
2482           return Error("Invalid ID");
2483         Section = SectionTable[Record[5]-1];
2484       }
2485       GlobalValue::VisibilityTypes Visibility = GlobalValue::DefaultVisibility;
2486       // Local linkage must have default visibility.
2487       if (Record.size() > 6 && !GlobalValue::isLocalLinkage(Linkage))
2488         // FIXME: Change to an error if non-default in 4.0.
2489         Visibility = GetDecodedVisibility(Record[6]);
2490 
2491       GlobalVariable::ThreadLocalMode TLM = GlobalVariable::NotThreadLocal;
2492       if (Record.size() > 7)
2493         TLM = GetDecodedThreadLocalMode(Record[7]);
2494 
2495       bool UnnamedAddr = false;
2496       if (Record.size() > 8)
2497         UnnamedAddr = Record[8];
2498 
2499       bool ExternallyInitialized = false;
2500       if (Record.size() > 9)
2501         ExternallyInitialized = Record[9];
2502 
2503       GlobalVariable *NewGV =
2504         new GlobalVariable(*TheModule, Ty, isConstant, Linkage, nullptr, "", nullptr,
2505                            TLM, AddressSpace, ExternallyInitialized);
2506       NewGV->setAlignment(Alignment);
2507       if (!Section.empty())
2508         NewGV->setSection(Section);
2509       NewGV->setVisibility(Visibility);
2510       NewGV->setUnnamedAddr(UnnamedAddr);
2511 
2512       if (Record.size() > 10)
2513         NewGV->setDLLStorageClass(GetDecodedDLLStorageClass(Record[10]));
2514       else
2515         UpgradeDLLImportExportLinkage(NewGV, RawLinkage);
2516 
2517       ValueList.push_back(NewGV);
2518 
2519       // Remember which value to use for the global initializer.
2520       if (unsigned InitID = Record[2])
2521         GlobalInits.push_back(std::make_pair(NewGV, InitID-1));
2522 
2523       if (Record.size() > 11) {
2524         if (unsigned ComdatID = Record[11]) {
2525           assert(ComdatID <= ComdatList.size());
2526           NewGV->setComdat(ComdatList[ComdatID - 1]);
2527         }
2528       } else if (hasImplicitComdat(RawLinkage)) {
2529         NewGV->setComdat(reinterpret_cast<Comdat *>(1));
2530       }
2531       break;
2532     }
2533     // FUNCTION:  [type, callingconv, isproto, linkage, paramattr,
2534     //             alignment, section, visibility, gc, unnamed_addr,
2535     //             prologuedata, dllstorageclass, comdat, prefixdata]
2536     case bitc::MODULE_CODE_FUNCTION: {
2537       if (Record.size() < 8)
2538         return Error("Invalid record");
2539       Type *Ty = getTypeByID(Record[0]);
2540       if (!Ty)
2541         return Error("Invalid record");
2542       if (!Ty->isPointerTy())
2543         return Error("Invalid type for value");
2544       FunctionType *FTy =
2545         dyn_cast<FunctionType>(cast<PointerType>(Ty)->getElementType());
2546       if (!FTy)
2547         return Error("Invalid type for value");
2548 
2549       Function *Func = Function::Create(FTy, GlobalValue::ExternalLinkage,
2550                                         "", TheModule);
2551 
2552       Func->setCallingConv(static_cast<CallingConv::ID>(Record[1]));
2553       bool isProto = Record[2];
2554       uint64_t RawLinkage = Record[3];
2555       Func->setLinkage(getDecodedLinkage(RawLinkage));
2556       Func->setAttributes(getAttributes(Record[4]));
2557 
2558       unsigned Alignment;
2559       if (std::error_code EC = parseAlignmentValue(Record[5], Alignment))
2560         return EC;
2561       Func->setAlignment(Alignment);
2562       if (Record[6]) {
2563         if (Record[6]-1 >= SectionTable.size())
2564           return Error("Invalid ID");
2565         Func->setSection(SectionTable[Record[6]-1]);
2566       }
2567       // Local linkage must have default visibility.
2568       if (!Func->hasLocalLinkage())
2569         // FIXME: Change to an error if non-default in 4.0.
2570         Func->setVisibility(GetDecodedVisibility(Record[7]));
2571       if (Record.size() > 8 && Record[8]) {
2572         if (Record[8]-1 > GCTable.size())
2573           return Error("Invalid ID");
2574         Func->setGC(GCTable[Record[8]-1].c_str());
2575       }
2576       bool UnnamedAddr = false;
2577       if (Record.size() > 9)
2578         UnnamedAddr = Record[9];
2579       Func->setUnnamedAddr(UnnamedAddr);
2580       if (Record.size() > 10 && Record[10] != 0)
2581         FunctionPrologues.push_back(std::make_pair(Func, Record[10]-1));
2582 
2583       if (Record.size() > 11)
2584         Func->setDLLStorageClass(GetDecodedDLLStorageClass(Record[11]));
2585       else
2586         UpgradeDLLImportExportLinkage(Func, RawLinkage);
2587 
2588       if (Record.size() > 12) {
2589         if (unsigned ComdatID = Record[12]) {
2590           assert(ComdatID <= ComdatList.size());
2591           Func->setComdat(ComdatList[ComdatID - 1]);
2592         }
2593       } else if (hasImplicitComdat(RawLinkage)) {
2594         Func->setComdat(reinterpret_cast<Comdat *>(1));
2595       }
2596 
2597       if (Record.size() > 13 && Record[13] != 0)
2598         FunctionPrefixes.push_back(std::make_pair(Func, Record[13]-1));
2599 
2600       ValueList.push_back(Func);
2601 
2602       // If this is a function with a body, remember the prototype we are
2603       // creating now, so that we can match up the body with them later.
2604       if (!isProto) {
2605         Func->setIsMaterializable(true);
2606         FunctionsWithBodies.push_back(Func);
2607         if (LazyStreamer)
2608           DeferredFunctionInfo[Func] = 0;
2609       }
2610       break;
2611     }
2612     // ALIAS: [alias type, aliasee val#, linkage]
2613     // ALIAS: [alias type, aliasee val#, linkage, visibility, dllstorageclass]
2614     case bitc::MODULE_CODE_ALIAS: {
2615       if (Record.size() < 3)
2616         return Error("Invalid record");
2617       Type *Ty = getTypeByID(Record[0]);
2618       if (!Ty)
2619         return Error("Invalid record");
2620       auto *PTy = dyn_cast<PointerType>(Ty);
2621       if (!PTy)
2622         return Error("Invalid type for value");
2623 
2624       auto *NewGA =
2625           GlobalAlias::create(PTy->getElementType(), PTy->getAddressSpace(),
2626                               getDecodedLinkage(Record[2]), "", TheModule);
2627       // Old bitcode files didn't have visibility field.
2628       // Local linkage must have default visibility.
2629       if (Record.size() > 3 && !NewGA->hasLocalLinkage())
2630         // FIXME: Change to an error if non-default in 4.0.
2631         NewGA->setVisibility(GetDecodedVisibility(Record[3]));
2632       if (Record.size() > 4)
2633         NewGA->setDLLStorageClass(GetDecodedDLLStorageClass(Record[4]));
2634       else
2635         UpgradeDLLImportExportLinkage(NewGA, Record[2]);
2636       if (Record.size() > 5)
2637         NewGA->setThreadLocalMode(GetDecodedThreadLocalMode(Record[5]));
2638       if (Record.size() > 6)
2639         NewGA->setUnnamedAddr(Record[6]);
2640       ValueList.push_back(NewGA);
2641       AliasInits.push_back(std::make_pair(NewGA, Record[1]));
2642       break;
2643     }
2644     /// MODULE_CODE_PURGEVALS: [numvals]
2645     case bitc::MODULE_CODE_PURGEVALS:
2646       // Trim down the value list to the specified size.
2647       if (Record.size() < 1 || Record[0] > ValueList.size())
2648         return Error("Invalid record");
2649       ValueList.shrinkTo(Record[0]);
2650       break;
2651     }
2652     Record.clear();
2653   }
2654 }
2655 
2656 std::error_code BitcodeReader::ParseBitcodeInto(Module *M) {
2657   TheModule = nullptr;
2658 
2659   if (std::error_code EC = InitStream())
2660     return EC;
2661 
2662   // Sniff for the signature.
2663   if (Stream.Read(8) != 'B' ||
2664       Stream.Read(8) != 'C' ||
2665       Stream.Read(4) != 0x0 ||
2666       Stream.Read(4) != 0xC ||
2667       Stream.Read(4) != 0xE ||
2668       Stream.Read(4) != 0xD)
2669     return Error("Invalid bitcode signature");
2670 
2671   // We expect a number of well-defined blocks, though we don't necessarily
2672   // need to understand them all.
2673   while (1) {
2674     if (Stream.AtEndOfStream())
2675       return std::error_code();
2676 
2677     BitstreamEntry Entry =
2678       Stream.advance(BitstreamCursor::AF_DontAutoprocessAbbrevs);
2679 
2680     switch (Entry.Kind) {
2681     case BitstreamEntry::Error:
2682       return Error("Malformed block");
2683     case BitstreamEntry::EndBlock:
2684       return std::error_code();
2685 
2686     case BitstreamEntry::SubBlock:
2687       switch (Entry.ID) {
2688       case bitc::BLOCKINFO_BLOCK_ID:
2689         if (Stream.ReadBlockInfoBlock())
2690           return Error("Malformed block");
2691         break;
2692       case bitc::MODULE_BLOCK_ID:
2693         // Reject multiple MODULE_BLOCK's in a single bitstream.
2694         if (TheModule)
2695           return Error("Invalid multiple blocks");
2696         TheModule = M;
2697         if (std::error_code EC = ParseModule(false))
2698           return EC;
2699         if (LazyStreamer)
2700           return std::error_code();
2701         break;
2702       default:
2703         if (Stream.SkipBlock())
2704           return Error("Invalid record");
2705         break;
2706       }
2707       continue;
2708     case BitstreamEntry::Record:
2709       // There should be no records in the top-level of blocks.
2710 
2711       // The ranlib in Xcode 4 will align archive members by appending newlines
2712       // to the end of them. If this file size is a multiple of 4 but not 8, we
2713       // have to read and ignore these final 4 bytes :-(
2714       if (Stream.getAbbrevIDWidth() == 2 && Entry.ID == 2 &&
2715           Stream.Read(6) == 2 && Stream.Read(24) == 0xa0a0a &&
2716           Stream.AtEndOfStream())
2717         return std::error_code();
2718 
2719       return Error("Invalid record");
2720     }
2721   }
2722 }
2723 
2724 ErrorOr<std::string> BitcodeReader::parseModuleTriple() {
2725   if (Stream.EnterSubBlock(bitc::MODULE_BLOCK_ID))
2726     return Error("Invalid record");
2727 
2728   SmallVector<uint64_t, 64> Record;
2729 
2730   std::string Triple;
2731   // Read all the records for this module.
2732   while (1) {
2733     BitstreamEntry Entry = Stream.advanceSkippingSubblocks();
2734 
2735     switch (Entry.Kind) {
2736     case BitstreamEntry::SubBlock: // Handled for us already.
2737     case BitstreamEntry::Error:
2738       return Error("Malformed block");
2739     case BitstreamEntry::EndBlock:
2740       return Triple;
2741     case BitstreamEntry::Record:
2742       // The interesting case.
2743       break;
2744     }
2745 
2746     // Read a record.
2747     switch (Stream.readRecord(Entry.ID, Record)) {
2748     default: break;  // Default behavior, ignore unknown content.
2749     case bitc::MODULE_CODE_TRIPLE: {  // TRIPLE: [strchr x N]
2750       std::string S;
2751       if (ConvertToString(Record, 0, S))
2752         return Error("Invalid record");
2753       Triple = S;
2754       break;
2755     }
2756     }
2757     Record.clear();
2758   }
2759   llvm_unreachable("Exit infinite loop");
2760 }
2761 
2762 ErrorOr<std::string> BitcodeReader::parseTriple() {
2763   if (std::error_code EC = InitStream())
2764     return EC;
2765 
2766   // Sniff for the signature.
2767   if (Stream.Read(8) != 'B' ||
2768       Stream.Read(8) != 'C' ||
2769       Stream.Read(4) != 0x0 ||
2770       Stream.Read(4) != 0xC ||
2771       Stream.Read(4) != 0xE ||
2772       Stream.Read(4) != 0xD)
2773     return Error("Invalid bitcode signature");
2774 
2775   // We expect a number of well-defined blocks, though we don't necessarily
2776   // need to understand them all.
2777   while (1) {
2778     BitstreamEntry Entry = Stream.advance();
2779 
2780     switch (Entry.Kind) {
2781     case BitstreamEntry::Error:
2782       return Error("Malformed block");
2783     case BitstreamEntry::EndBlock:
2784       return std::error_code();
2785 
2786     case BitstreamEntry::SubBlock:
2787       if (Entry.ID == bitc::MODULE_BLOCK_ID)
2788         return parseModuleTriple();
2789 
2790       // Ignore other sub-blocks.
2791       if (Stream.SkipBlock())
2792         return Error("Malformed block");
2793       continue;
2794 
2795     case BitstreamEntry::Record:
2796       Stream.skipRecord(Entry.ID);
2797       continue;
2798     }
2799   }
2800 }
2801 
2802 /// ParseMetadataAttachment - Parse metadata attachments.
2803 std::error_code BitcodeReader::ParseMetadataAttachment() {
2804   if (Stream.EnterSubBlock(bitc::METADATA_ATTACHMENT_ID))
2805     return Error("Invalid record");
2806 
2807   SmallVector<uint64_t, 64> Record;
2808   while (1) {
2809     BitstreamEntry Entry = Stream.advanceSkippingSubblocks();
2810 
2811     switch (Entry.Kind) {
2812     case BitstreamEntry::SubBlock: // Handled for us already.
2813     case BitstreamEntry::Error:
2814       return Error("Malformed block");
2815     case BitstreamEntry::EndBlock:
2816       return std::error_code();
2817     case BitstreamEntry::Record:
2818       // The interesting case.
2819       break;
2820     }
2821 
2822     // Read a metadata attachment record.
2823     Record.clear();
2824     switch (Stream.readRecord(Entry.ID, Record)) {
2825     default:  // Default behavior: ignore.
2826       break;
2827     case bitc::METADATA_ATTACHMENT: {
2828       unsigned RecordLength = Record.size();
2829       if (Record.empty() || (RecordLength - 1) % 2 == 1)
2830         return Error("Invalid record");
2831       Instruction *Inst = InstructionList[Record[0]];
2832       for (unsigned i = 1; i != RecordLength; i = i+2) {
2833         unsigned Kind = Record[i];
2834         DenseMap<unsigned, unsigned>::iterator I =
2835           MDKindMap.find(Kind);
2836         if (I == MDKindMap.end())
2837           return Error("Invalid ID");
2838         Metadata *Node = MDValueList.getValueFwdRef(Record[i + 1]);
2839         if (isa<LocalAsMetadata>(Node))
2840           // Drop the attachment.  This used to be legal, but there's no
2841           // upgrade path.
2842           break;
2843         Inst->setMetadata(I->second, cast<MDNode>(Node));
2844         if (I->second == LLVMContext::MD_tbaa)
2845           InstsWithTBAATag.push_back(Inst);
2846       }
2847       break;
2848     }
2849     }
2850   }
2851 }
2852 
2853 /// ParseFunctionBody - Lazily parse the specified function body block.
2854 std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
2855   if (Stream.EnterSubBlock(bitc::FUNCTION_BLOCK_ID))
2856     return Error("Invalid record");
2857 
2858   InstructionList.clear();
2859   unsigned ModuleValueListSize = ValueList.size();
2860   unsigned ModuleMDValueListSize = MDValueList.size();
2861 
2862   // Add all the function arguments to the value table.
2863   for(Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); I != E; ++I)
2864     ValueList.push_back(I);
2865 
2866   unsigned NextValueNo = ValueList.size();
2867   BasicBlock *CurBB = nullptr;
2868   unsigned CurBBNo = 0;
2869 
2870   DebugLoc LastLoc;
2871   auto getLastInstruction = [&]() -> Instruction * {
2872     if (CurBB && !CurBB->empty())
2873       return &CurBB->back();
2874     else if (CurBBNo && FunctionBBs[CurBBNo - 1] &&
2875              !FunctionBBs[CurBBNo - 1]->empty())
2876       return &FunctionBBs[CurBBNo - 1]->back();
2877     return nullptr;
2878   };
2879 
2880   // Read all the records.
2881   SmallVector<uint64_t, 64> Record;
2882   while (1) {
2883     BitstreamEntry Entry = Stream.advance();
2884 
2885     switch (Entry.Kind) {
2886     case BitstreamEntry::Error:
2887       return Error("Malformed block");
2888     case BitstreamEntry::EndBlock:
2889       goto OutOfRecordLoop;
2890 
2891     case BitstreamEntry::SubBlock:
2892       switch (Entry.ID) {
2893       default:  // Skip unknown content.
2894         if (Stream.SkipBlock())
2895           return Error("Invalid record");
2896         break;
2897       case bitc::CONSTANTS_BLOCK_ID:
2898         if (std::error_code EC = ParseConstants())
2899           return EC;
2900         NextValueNo = ValueList.size();
2901         break;
2902       case bitc::VALUE_SYMTAB_BLOCK_ID:
2903         if (std::error_code EC = ParseValueSymbolTable())
2904           return EC;
2905         break;
2906       case bitc::METADATA_ATTACHMENT_ID:
2907         if (std::error_code EC = ParseMetadataAttachment())
2908           return EC;
2909         break;
2910       case bitc::METADATA_BLOCK_ID:
2911         if (std::error_code EC = ParseMetadata())
2912           return EC;
2913         break;
2914       case bitc::USELIST_BLOCK_ID:
2915         if (std::error_code EC = ParseUseLists())
2916           return EC;
2917         break;
2918       }
2919       continue;
2920 
2921     case BitstreamEntry::Record:
2922       // The interesting case.
2923       break;
2924     }
2925 
2926     // Read a record.
2927     Record.clear();
2928     Instruction *I = nullptr;
2929     unsigned BitCode = Stream.readRecord(Entry.ID, Record);
2930     switch (BitCode) {
2931     default: // Default behavior: reject
2932       return Error("Invalid value");
2933     case bitc::FUNC_CODE_DECLAREBLOCKS: {   // DECLAREBLOCKS: [nblocks]
2934       if (Record.size() < 1 || Record[0] == 0)
2935         return Error("Invalid record");
2936       // Create all the basic blocks for the function.
2937       FunctionBBs.resize(Record[0]);
2938 
2939       // See if anything took the address of blocks in this function.
2940       auto BBFRI = BasicBlockFwdRefs.find(F);
2941       if (BBFRI == BasicBlockFwdRefs.end()) {
2942         for (unsigned i = 0, e = FunctionBBs.size(); i != e; ++i)
2943           FunctionBBs[i] = BasicBlock::Create(Context, "", F);
2944       } else {
2945         auto &BBRefs = BBFRI->second;
2946         // Check for invalid basic block references.
2947         if (BBRefs.size() > FunctionBBs.size())
2948           return Error("Invalid ID");
2949         assert(!BBRefs.empty() && "Unexpected empty array");
2950         assert(!BBRefs.front() && "Invalid reference to entry block");
2951         for (unsigned I = 0, E = FunctionBBs.size(), RE = BBRefs.size(); I != E;
2952              ++I)
2953           if (I < RE && BBRefs[I]) {
2954             BBRefs[I]->insertInto(F);
2955             FunctionBBs[I] = BBRefs[I];
2956           } else {
2957             FunctionBBs[I] = BasicBlock::Create(Context, "", F);
2958           }
2959 
2960         // Erase from the table.
2961         BasicBlockFwdRefs.erase(BBFRI);
2962       }
2963 
2964       CurBB = FunctionBBs[0];
2965       continue;
2966     }
2967 
2968     case bitc::FUNC_CODE_DEBUG_LOC_AGAIN:  // DEBUG_LOC_AGAIN
2969       // This record indicates that the last instruction is at the same
2970       // location as the previous instruction with a location.
2971       I = getLastInstruction();
2972 
2973       if (!I)
2974         return Error("Invalid record");
2975       I->setDebugLoc(LastLoc);
2976       I = nullptr;
2977       continue;
2978 
2979     case bitc::FUNC_CODE_DEBUG_LOC: {      // DEBUG_LOC: [line, col, scope, ia]
2980       I = getLastInstruction();
2981       if (!I || Record.size() < 4)
2982         return Error("Invalid record");
2983 
2984       unsigned Line = Record[0], Col = Record[1];
2985       unsigned ScopeID = Record[2], IAID = Record[3];
2986 
2987       MDNode *Scope = nullptr, *IA = nullptr;
2988       if (ScopeID) Scope = cast<MDNode>(MDValueList.getValueFwdRef(ScopeID-1));
2989       if (IAID)    IA = cast<MDNode>(MDValueList.getValueFwdRef(IAID-1));
2990       LastLoc = DebugLoc::get(Line, Col, Scope, IA);
2991       I->setDebugLoc(LastLoc);
2992       I = nullptr;
2993       continue;
2994     }
2995 
2996     case bitc::FUNC_CODE_INST_BINOP: {    // BINOP: [opval, ty, opval, opcode]
2997       unsigned OpNum = 0;
2998       Value *LHS, *RHS;
2999       if (getValueTypePair(Record, OpNum, NextValueNo, LHS) ||
3000           popValue(Record, OpNum, NextValueNo, LHS->getType(), RHS) ||
3001           OpNum+1 > Record.size())
3002         return Error("Invalid record");
3003 
3004       int Opc = GetDecodedBinaryOpcode(Record[OpNum++], LHS->getType());
3005       if (Opc == -1)
3006         return Error("Invalid record");
3007       I = BinaryOperator::Create((Instruction::BinaryOps)Opc, LHS, RHS);
3008       InstructionList.push_back(I);
3009       if (OpNum < Record.size()) {
3010         if (Opc == Instruction::Add ||
3011             Opc == Instruction::Sub ||
3012             Opc == Instruction::Mul ||
3013             Opc == Instruction::Shl) {
3014           if (Record[OpNum] & (1 << bitc::OBO_NO_SIGNED_WRAP))
3015             cast<BinaryOperator>(I)->setHasNoSignedWrap(true);
3016           if (Record[OpNum] & (1 << bitc::OBO_NO_UNSIGNED_WRAP))
3017             cast<BinaryOperator>(I)->setHasNoUnsignedWrap(true);
3018         } else if (Opc == Instruction::SDiv ||
3019                    Opc == Instruction::UDiv ||
3020                    Opc == Instruction::LShr ||
3021                    Opc == Instruction::AShr) {
3022           if (Record[OpNum] & (1 << bitc::PEO_EXACT))
3023             cast<BinaryOperator>(I)->setIsExact(true);
3024         } else if (isa<FPMathOperator>(I)) {
3025           FastMathFlags FMF;
3026           if (0 != (Record[OpNum] & FastMathFlags::UnsafeAlgebra))
3027             FMF.setUnsafeAlgebra();
3028           if (0 != (Record[OpNum] & FastMathFlags::NoNaNs))
3029             FMF.setNoNaNs();
3030           if (0 != (Record[OpNum] & FastMathFlags::NoInfs))
3031             FMF.setNoInfs();
3032           if (0 != (Record[OpNum] & FastMathFlags::NoSignedZeros))
3033             FMF.setNoSignedZeros();
3034           if (0 != (Record[OpNum] & FastMathFlags::AllowReciprocal))
3035             FMF.setAllowReciprocal();
3036           if (FMF.any())
3037             I->setFastMathFlags(FMF);
3038         }
3039 
3040       }
3041       break;
3042     }
3043     case bitc::FUNC_CODE_INST_CAST: {    // CAST: [opval, opty, destty, castopc]
3044       unsigned OpNum = 0;
3045       Value *Op;
3046       if (getValueTypePair(Record, OpNum, NextValueNo, Op) ||
3047           OpNum+2 != Record.size())
3048         return Error("Invalid record");
3049 
3050       Type *ResTy = getTypeByID(Record[OpNum]);
3051       int Opc = GetDecodedCastOpcode(Record[OpNum+1]);
3052       if (Opc == -1 || !ResTy)
3053         return Error("Invalid record");
3054       Instruction *Temp = nullptr;
3055       if ((I = UpgradeBitCastInst(Opc, Op, ResTy, Temp))) {
3056         if (Temp) {
3057           InstructionList.push_back(Temp);
3058           CurBB->getInstList().push_back(Temp);
3059         }
3060       } else {
3061         I = CastInst::Create((Instruction::CastOps)Opc, Op, ResTy);
3062       }
3063       InstructionList.push_back(I);
3064       break;
3065     }
3066     case bitc::FUNC_CODE_INST_INBOUNDS_GEP_OLD:
3067     case bitc::FUNC_CODE_INST_GEP_OLD:
3068     case bitc::FUNC_CODE_INST_GEP: { // GEP: type, [n x operands]
3069       unsigned OpNum = 0;
3070 
3071       Type *Ty;
3072       bool InBounds;
3073 
3074       if (BitCode == bitc::FUNC_CODE_INST_GEP) {
3075         InBounds = Record[OpNum++];
3076         Ty = getTypeByID(Record[OpNum++]);
3077       } else {
3078         InBounds = BitCode == bitc::FUNC_CODE_INST_INBOUNDS_GEP_OLD;
3079         Ty = nullptr;
3080       }
3081 
3082       Value *BasePtr;
3083       if (getValueTypePair(Record, OpNum, NextValueNo, BasePtr))
3084         return Error("Invalid record");
3085 
3086       SmallVector<Value*, 16> GEPIdx;
3087       while (OpNum != Record.size()) {
3088         Value *Op;
3089         if (getValueTypePair(Record, OpNum, NextValueNo, Op))
3090           return Error("Invalid record");
3091         GEPIdx.push_back(Op);
3092       }
3093 
3094       I = GetElementPtrInst::Create(BasePtr, GEPIdx);
3095       (void)Ty;
3096       assert(!Ty || Ty == cast<GetElementPtrInst>(I)->getSourceElementType());
3097       InstructionList.push_back(I);
3098       if (InBounds)
3099         cast<GetElementPtrInst>(I)->setIsInBounds(true);
3100       break;
3101     }
3102 
3103     case bitc::FUNC_CODE_INST_EXTRACTVAL: {
3104                                        // EXTRACTVAL: [opty, opval, n x indices]
3105       unsigned OpNum = 0;
3106       Value *Agg;
3107       if (getValueTypePair(Record, OpNum, NextValueNo, Agg))
3108         return Error("Invalid record");
3109 
3110       SmallVector<unsigned, 4> EXTRACTVALIdx;
3111       Type *CurTy = Agg->getType();
3112       for (unsigned RecSize = Record.size();
3113            OpNum != RecSize; ++OpNum) {
3114         bool IsArray = CurTy->isArrayTy();
3115         bool IsStruct = CurTy->isStructTy();
3116         uint64_t Index = Record[OpNum];
3117 
3118         if (!IsStruct && !IsArray)
3119           return Error("EXTRACTVAL: Invalid type");
3120         if ((unsigned)Index != Index)
3121           return Error("Invalid value");
3122         if (IsStruct && Index >= CurTy->subtypes().size())
3123           return Error("EXTRACTVAL: Invalid struct index");
3124         if (IsArray && Index >= CurTy->getArrayNumElements())
3125           return Error("EXTRACTVAL: Invalid array index");
3126         EXTRACTVALIdx.push_back((unsigned)Index);
3127 
3128         if (IsStruct)
3129           CurTy = CurTy->subtypes()[Index];
3130         else
3131           CurTy = CurTy->subtypes()[0];
3132       }
3133 
3134       I = ExtractValueInst::Create(Agg, EXTRACTVALIdx);
3135       InstructionList.push_back(I);
3136       break;
3137     }
3138 
3139     case bitc::FUNC_CODE_INST_INSERTVAL: {
3140                            // INSERTVAL: [opty, opval, opty, opval, n x indices]
3141       unsigned OpNum = 0;
3142       Value *Agg;
3143       if (getValueTypePair(Record, OpNum, NextValueNo, Agg))
3144         return Error("Invalid record");
3145       Value *Val;
3146       if (getValueTypePair(Record, OpNum, NextValueNo, Val))
3147         return Error("Invalid record");
3148 
3149       SmallVector<unsigned, 4> INSERTVALIdx;
3150       Type *CurTy = Agg->getType();
3151       for (unsigned RecSize = Record.size();
3152            OpNum != RecSize; ++OpNum) {
3153         bool IsArray = CurTy->isArrayTy();
3154         bool IsStruct = CurTy->isStructTy();
3155         uint64_t Index = Record[OpNum];
3156 
3157         if (!IsStruct && !IsArray)
3158           return Error("INSERTVAL: Invalid type");
3159         if (!CurTy->isStructTy() && !CurTy->isArrayTy())
3160           return Error("Invalid type");
3161         if ((unsigned)Index != Index)
3162           return Error("Invalid value");
3163         if (IsStruct && Index >= CurTy->subtypes().size())
3164           return Error("INSERTVAL: Invalid struct index");
3165         if (IsArray && Index >= CurTy->getArrayNumElements())
3166           return Error("INSERTVAL: Invalid array index");
3167 
3168         INSERTVALIdx.push_back((unsigned)Index);
3169         if (IsStruct)
3170           CurTy = CurTy->subtypes()[Index];
3171         else
3172           CurTy = CurTy->subtypes()[0];
3173       }
3174 
3175       I = InsertValueInst::Create(Agg, Val, INSERTVALIdx);
3176       InstructionList.push_back(I);
3177       break;
3178     }
3179 
3180     case bitc::FUNC_CODE_INST_SELECT: { // SELECT: [opval, ty, opval, opval]
3181       // obsolete form of select
3182       // handles select i1 ... in old bitcode
3183       unsigned OpNum = 0;
3184       Value *TrueVal, *FalseVal, *Cond;
3185       if (getValueTypePair(Record, OpNum, NextValueNo, TrueVal) ||
3186           popValue(Record, OpNum, NextValueNo, TrueVal->getType(), FalseVal) ||
3187           popValue(Record, OpNum, NextValueNo, Type::getInt1Ty(Context), Cond))
3188         return Error("Invalid record");
3189 
3190       I = SelectInst::Create(Cond, TrueVal, FalseVal);
3191       InstructionList.push_back(I);
3192       break;
3193     }
3194 
3195     case bitc::FUNC_CODE_INST_VSELECT: {// VSELECT: [ty,opval,opval,predty,pred]
3196       // new form of select
3197       // handles select i1 or select [N x i1]
3198       unsigned OpNum = 0;
3199       Value *TrueVal, *FalseVal, *Cond;
3200       if (getValueTypePair(Record, OpNum, NextValueNo, TrueVal) ||
3201           popValue(Record, OpNum, NextValueNo, TrueVal->getType(), FalseVal) ||
3202           getValueTypePair(Record, OpNum, NextValueNo, Cond))
3203         return Error("Invalid record");
3204 
3205       // select condition can be either i1 or [N x i1]
3206       if (VectorType* vector_type =
3207           dyn_cast<VectorType>(Cond->getType())) {
3208         // expect <n x i1>
3209         if (vector_type->getElementType() != Type::getInt1Ty(Context))
3210           return Error("Invalid type for value");
3211       } else {
3212         // expect i1
3213         if (Cond->getType() != Type::getInt1Ty(Context))
3214           return Error("Invalid type for value");
3215       }
3216 
3217       I = SelectInst::Create(Cond, TrueVal, FalseVal);
3218       InstructionList.push_back(I);
3219       break;
3220     }
3221 
3222     case bitc::FUNC_CODE_INST_EXTRACTELT: { // EXTRACTELT: [opty, opval, opval]
3223       unsigned OpNum = 0;
3224       Value *Vec, *Idx;
3225       if (getValueTypePair(Record, OpNum, NextValueNo, Vec) ||
3226           getValueTypePair(Record, OpNum, NextValueNo, Idx))
3227         return Error("Invalid record");
3228       I = ExtractElementInst::Create(Vec, Idx);
3229       InstructionList.push_back(I);
3230       break;
3231     }
3232 
3233     case bitc::FUNC_CODE_INST_INSERTELT: { // INSERTELT: [ty, opval,opval,opval]
3234       unsigned OpNum = 0;
3235       Value *Vec, *Elt, *Idx;
3236       if (getValueTypePair(Record, OpNum, NextValueNo, Vec) ||
3237           popValue(Record, OpNum, NextValueNo,
3238                    cast<VectorType>(Vec->getType())->getElementType(), Elt) ||
3239           getValueTypePair(Record, OpNum, NextValueNo, Idx))
3240         return Error("Invalid record");
3241       I = InsertElementInst::Create(Vec, Elt, Idx);
3242       InstructionList.push_back(I);
3243       break;
3244     }
3245 
3246     case bitc::FUNC_CODE_INST_SHUFFLEVEC: {// SHUFFLEVEC: [opval,ty,opval,opval]
3247       unsigned OpNum = 0;
3248       Value *Vec1, *Vec2, *Mask;
3249       if (getValueTypePair(Record, OpNum, NextValueNo, Vec1) ||
3250           popValue(Record, OpNum, NextValueNo, Vec1->getType(), Vec2))
3251         return Error("Invalid record");
3252 
3253       if (getValueTypePair(Record, OpNum, NextValueNo, Mask))
3254         return Error("Invalid record");
3255       I = new ShuffleVectorInst(Vec1, Vec2, Mask);
3256       InstructionList.push_back(I);
3257       break;
3258     }
3259 
3260     case bitc::FUNC_CODE_INST_CMP:   // CMP: [opty, opval, opval, pred]
3261       // Old form of ICmp/FCmp returning bool
3262       // Existed to differentiate between icmp/fcmp and vicmp/vfcmp which were
3263       // both legal on vectors but had different behaviour.
3264     case bitc::FUNC_CODE_INST_CMP2: { // CMP2: [opty, opval, opval, pred]
3265       // FCmp/ICmp returning bool or vector of bool
3266 
3267       unsigned OpNum = 0;
3268       Value *LHS, *RHS;
3269       if (getValueTypePair(Record, OpNum, NextValueNo, LHS) ||
3270           popValue(Record, OpNum, NextValueNo, LHS->getType(), RHS) ||
3271           OpNum+1 != Record.size())
3272         return Error("Invalid record");
3273 
3274       if (LHS->getType()->isFPOrFPVectorTy())
3275         I = new FCmpInst((FCmpInst::Predicate)Record[OpNum], LHS, RHS);
3276       else
3277         I = new ICmpInst((ICmpInst::Predicate)Record[OpNum], LHS, RHS);
3278       InstructionList.push_back(I);
3279       break;
3280     }
3281 
3282     case bitc::FUNC_CODE_INST_RET: // RET: [opty,opval<optional>]
3283       {
3284         unsigned Size = Record.size();
3285         if (Size == 0) {
3286           I = ReturnInst::Create(Context);
3287           InstructionList.push_back(I);
3288           break;
3289         }
3290 
3291         unsigned OpNum = 0;
3292         Value *Op = nullptr;
3293         if (getValueTypePair(Record, OpNum, NextValueNo, Op))
3294           return Error("Invalid record");
3295         if (OpNum != Record.size())
3296           return Error("Invalid record");
3297 
3298         I = ReturnInst::Create(Context, Op);
3299         InstructionList.push_back(I);
3300         break;
3301       }
3302     case bitc::FUNC_CODE_INST_BR: { // BR: [bb#, bb#, opval] or [bb#]
3303       if (Record.size() != 1 && Record.size() != 3)
3304         return Error("Invalid record");
3305       BasicBlock *TrueDest = getBasicBlock(Record[0]);
3306       if (!TrueDest)
3307         return Error("Invalid record");
3308 
3309       if (Record.size() == 1) {
3310         I = BranchInst::Create(TrueDest);
3311         InstructionList.push_back(I);
3312       }
3313       else {
3314         BasicBlock *FalseDest = getBasicBlock(Record[1]);
3315         Value *Cond = getValue(Record, 2, NextValueNo,
3316                                Type::getInt1Ty(Context));
3317         if (!FalseDest || !Cond)
3318           return Error("Invalid record");
3319         I = BranchInst::Create(TrueDest, FalseDest, Cond);
3320         InstructionList.push_back(I);
3321       }
3322       break;
3323     }
3324     case bitc::FUNC_CODE_INST_SWITCH: { // SWITCH: [opty, op0, op1, ...]
3325       // Check magic
3326       if ((Record[0] >> 16) == SWITCH_INST_MAGIC) {
3327         // "New" SwitchInst format with case ranges. The changes to write this
3328         // format were reverted but we still recognize bitcode that uses it.
3329         // Hopefully someday we will have support for case ranges and can use
3330         // this format again.
3331 
3332         Type *OpTy = getTypeByID(Record[1]);
3333         unsigned ValueBitWidth = cast<IntegerType>(OpTy)->getBitWidth();
3334 
3335         Value *Cond = getValue(Record, 2, NextValueNo, OpTy);
3336         BasicBlock *Default = getBasicBlock(Record[3]);
3337         if (!OpTy || !Cond || !Default)
3338           return Error("Invalid record");
3339 
3340         unsigned NumCases = Record[4];
3341 
3342         SwitchInst *SI = SwitchInst::Create(Cond, Default, NumCases);
3343         InstructionList.push_back(SI);
3344 
3345         unsigned CurIdx = 5;
3346         for (unsigned i = 0; i != NumCases; ++i) {
3347           SmallVector<ConstantInt*, 1> CaseVals;
3348           unsigned NumItems = Record[CurIdx++];
3349           for (unsigned ci = 0; ci != NumItems; ++ci) {
3350             bool isSingleNumber = Record[CurIdx++];
3351 
3352             APInt Low;
3353             unsigned ActiveWords = 1;
3354             if (ValueBitWidth > 64)
3355               ActiveWords = Record[CurIdx++];
3356             Low = ReadWideAPInt(makeArrayRef(&Record[CurIdx], ActiveWords),
3357                                 ValueBitWidth);
3358             CurIdx += ActiveWords;
3359 
3360             if (!isSingleNumber) {
3361               ActiveWords = 1;
3362               if (ValueBitWidth > 64)
3363                 ActiveWords = Record[CurIdx++];
3364               APInt High =
3365                   ReadWideAPInt(makeArrayRef(&Record[CurIdx], ActiveWords),
3366                                 ValueBitWidth);
3367               CurIdx += ActiveWords;
3368 
3369               // FIXME: It is not clear whether values in the range should be
3370               // compared as signed or unsigned values. The partially
3371               // implemented changes that used this format in the past used
3372               // unsigned comparisons.
3373               for ( ; Low.ule(High); ++Low)
3374                 CaseVals.push_back(ConstantInt::get(Context, Low));
3375             } else
3376               CaseVals.push_back(ConstantInt::get(Context, Low));
3377           }
3378           BasicBlock *DestBB = getBasicBlock(Record[CurIdx++]);
3379           for (SmallVector<ConstantInt*, 1>::iterator cvi = CaseVals.begin(),
3380                  cve = CaseVals.end(); cvi != cve; ++cvi)
3381             SI->addCase(*cvi, DestBB);
3382         }
3383         I = SI;
3384         break;
3385       }
3386 
3387       // Old SwitchInst format without case ranges.
3388 
3389       if (Record.size() < 3 || (Record.size() & 1) == 0)
3390         return Error("Invalid record");
3391       Type *OpTy = getTypeByID(Record[0]);
3392       Value *Cond = getValue(Record, 1, NextValueNo, OpTy);
3393       BasicBlock *Default = getBasicBlock(Record[2]);
3394       if (!OpTy || !Cond || !Default)
3395         return Error("Invalid record");
3396       unsigned NumCases = (Record.size()-3)/2;
3397       SwitchInst *SI = SwitchInst::Create(Cond, Default, NumCases);
3398       InstructionList.push_back(SI);
3399       for (unsigned i = 0, e = NumCases; i != e; ++i) {
3400         ConstantInt *CaseVal =
3401           dyn_cast_or_null<ConstantInt>(getFnValueByID(Record[3+i*2], OpTy));
3402         BasicBlock *DestBB = getBasicBlock(Record[1+3+i*2]);
3403         if (!CaseVal || !DestBB) {
3404           delete SI;
3405           return Error("Invalid record");
3406         }
3407         SI->addCase(CaseVal, DestBB);
3408       }
3409       I = SI;
3410       break;
3411     }
3412     case bitc::FUNC_CODE_INST_INDIRECTBR: { // INDIRECTBR: [opty, op0, op1, ...]
3413       if (Record.size() < 2)
3414         return Error("Invalid record");
3415       Type *OpTy = getTypeByID(Record[0]);
3416       Value *Address = getValue(Record, 1, NextValueNo, OpTy);
3417       if (!OpTy || !Address)
3418         return Error("Invalid record");
3419       unsigned NumDests = Record.size()-2;
3420       IndirectBrInst *IBI = IndirectBrInst::Create(Address, NumDests);
3421       InstructionList.push_back(IBI);
3422       for (unsigned i = 0, e = NumDests; i != e; ++i) {
3423         if (BasicBlock *DestBB = getBasicBlock(Record[2+i])) {
3424           IBI->addDestination(DestBB);
3425         } else {
3426           delete IBI;
3427           return Error("Invalid record");
3428         }
3429       }
3430       I = IBI;
3431       break;
3432     }
3433 
3434     case bitc::FUNC_CODE_INST_INVOKE: {
3435       // INVOKE: [attrs, cc, normBB, unwindBB, fnty, op0,op1,op2, ...]
3436       if (Record.size() < 4)
3437         return Error("Invalid record");
3438       AttributeSet PAL = getAttributes(Record[0]);
3439       unsigned CCInfo = Record[1];
3440       BasicBlock *NormalBB = getBasicBlock(Record[2]);
3441       BasicBlock *UnwindBB = getBasicBlock(Record[3]);
3442 
3443       unsigned OpNum = 4;
3444       Value *Callee;
3445       if (getValueTypePair(Record, OpNum, NextValueNo, Callee))
3446         return Error("Invalid record");
3447 
3448       PointerType *CalleeTy = dyn_cast<PointerType>(Callee->getType());
3449       FunctionType *FTy = !CalleeTy ? nullptr :
3450         dyn_cast<FunctionType>(CalleeTy->getElementType());
3451 
3452       // Check that the right number of fixed parameters are here.
3453       if (!FTy || !NormalBB || !UnwindBB ||
3454           Record.size() < OpNum+FTy->getNumParams())
3455         return Error("Invalid record");
3456 
3457       SmallVector<Value*, 16> Ops;
3458       for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i, ++OpNum) {
3459         Ops.push_back(getValue(Record, OpNum, NextValueNo,
3460                                FTy->getParamType(i)));
3461         if (!Ops.back())
3462           return Error("Invalid record");
3463       }
3464 
3465       if (!FTy->isVarArg()) {
3466         if (Record.size() != OpNum)
3467           return Error("Invalid record");
3468       } else {
3469         // Read type/value pairs for varargs params.
3470         while (OpNum != Record.size()) {
3471           Value *Op;
3472           if (getValueTypePair(Record, OpNum, NextValueNo, Op))
3473             return Error("Invalid record");
3474           Ops.push_back(Op);
3475         }
3476       }
3477 
3478       I = InvokeInst::Create(Callee, NormalBB, UnwindBB, Ops);
3479       InstructionList.push_back(I);
3480       cast<InvokeInst>(I)->setCallingConv(
3481         static_cast<CallingConv::ID>(CCInfo));
3482       cast<InvokeInst>(I)->setAttributes(PAL);
3483       break;
3484     }
3485     case bitc::FUNC_CODE_INST_RESUME: { // RESUME: [opval]
3486       unsigned Idx = 0;
3487       Value *Val = nullptr;
3488       if (getValueTypePair(Record, Idx, NextValueNo, Val))
3489         return Error("Invalid record");
3490       I = ResumeInst::Create(Val);
3491       InstructionList.push_back(I);
3492       break;
3493     }
3494     case bitc::FUNC_CODE_INST_UNREACHABLE: // UNREACHABLE
3495       I = new UnreachableInst(Context);
3496       InstructionList.push_back(I);
3497       break;
3498     case bitc::FUNC_CODE_INST_PHI: { // PHI: [ty, val0,bb0, ...]
3499       if (Record.size() < 1 || ((Record.size()-1)&1))
3500         return Error("Invalid record");
3501       Type *Ty = getTypeByID(Record[0]);
3502       if (!Ty)
3503         return Error("Invalid record");
3504 
3505       PHINode *PN = PHINode::Create(Ty, (Record.size()-1)/2);
3506       InstructionList.push_back(PN);
3507 
3508       for (unsigned i = 0, e = Record.size()-1; i != e; i += 2) {
3509         Value *V;
3510         // With the new function encoding, it is possible that operands have
3511         // negative IDs (for forward references).  Use a signed VBR
3512         // representation to keep the encoding small.
3513         if (UseRelativeIDs)
3514           V = getValueSigned(Record, 1+i, NextValueNo, Ty);
3515         else
3516           V = getValue(Record, 1+i, NextValueNo, Ty);
3517         BasicBlock *BB = getBasicBlock(Record[2+i]);
3518         if (!V || !BB)
3519           return Error("Invalid record");
3520         PN->addIncoming(V, BB);
3521       }
3522       I = PN;
3523       break;
3524     }
3525 
3526     case bitc::FUNC_CODE_INST_LANDINGPAD: {
3527       // LANDINGPAD: [ty, val, val, num, (id0,val0 ...)?]
3528       unsigned Idx = 0;
3529       if (Record.size() < 4)
3530         return Error("Invalid record");
3531       Type *Ty = getTypeByID(Record[Idx++]);
3532       if (!Ty)
3533         return Error("Invalid record");
3534       Value *PersFn = nullptr;
3535       if (getValueTypePair(Record, Idx, NextValueNo, PersFn))
3536         return Error("Invalid record");
3537 
3538       bool IsCleanup = !!Record[Idx++];
3539       unsigned NumClauses = Record[Idx++];
3540       LandingPadInst *LP = LandingPadInst::Create(Ty, PersFn, NumClauses);
3541       LP->setCleanup(IsCleanup);
3542       for (unsigned J = 0; J != NumClauses; ++J) {
3543         LandingPadInst::ClauseType CT =
3544           LandingPadInst::ClauseType(Record[Idx++]); (void)CT;
3545         Value *Val;
3546 
3547         if (getValueTypePair(Record, Idx, NextValueNo, Val)) {
3548           delete LP;
3549           return Error("Invalid record");
3550         }
3551 
3552         assert((CT != LandingPadInst::Catch ||
3553                 !isa<ArrayType>(Val->getType())) &&
3554                "Catch clause has a invalid type!");
3555         assert((CT != LandingPadInst::Filter ||
3556                 isa<ArrayType>(Val->getType())) &&
3557                "Filter clause has invalid type!");
3558         LP->addClause(cast<Constant>(Val));
3559       }
3560 
3561       I = LP;
3562       InstructionList.push_back(I);
3563       break;
3564     }
3565 
3566     case bitc::FUNC_CODE_INST_ALLOCA: { // ALLOCA: [instty, opty, op, align]
3567       if (Record.size() != 4)
3568         return Error("Invalid record");
3569       PointerType *Ty =
3570         dyn_cast_or_null<PointerType>(getTypeByID(Record[0]));
3571       Type *OpTy = getTypeByID(Record[1]);
3572       Value *Size = getFnValueByID(Record[2], OpTy);
3573       uint64_t AlignRecord = Record[3];
3574       const uint64_t InAllocaMask = uint64_t(1) << 5;
3575       bool InAlloca = AlignRecord & InAllocaMask;
3576       unsigned Align;
3577       if (std::error_code EC =
3578           parseAlignmentValue(AlignRecord & ~InAllocaMask, Align)) {
3579         return EC;
3580       }
3581       if (!Ty || !Size)
3582         return Error("Invalid record");
3583       AllocaInst *AI = new AllocaInst(Ty->getElementType(), Size, Align);
3584       AI->setUsedWithInAlloca(InAlloca);
3585       I = AI;
3586       InstructionList.push_back(I);
3587       break;
3588     }
3589     case bitc::FUNC_CODE_INST_LOAD: { // LOAD: [opty, op, align, vol]
3590       unsigned OpNum = 0;
3591       Value *Op;
3592       if (getValueTypePair(Record, OpNum, NextValueNo, Op) ||
3593           (OpNum + 2 != Record.size() && OpNum + 3 != Record.size()))
3594         return Error("Invalid record");
3595 
3596       Type *Ty = nullptr;
3597       if (OpNum + 3 == Record.size())
3598         Ty = getTypeByID(Record[OpNum++]);
3599 
3600       unsigned Align;
3601       if (std::error_code EC = parseAlignmentValue(Record[OpNum], Align))
3602         return EC;
3603       I = new LoadInst(Op, "", Record[OpNum+1], Align);
3604 
3605       (void)Ty;
3606       assert((!Ty || Ty == I->getType()) &&
3607              "Explicit type doesn't match pointee type of the first operand");
3608 
3609       InstructionList.push_back(I);
3610       break;
3611     }
3612     case bitc::FUNC_CODE_INST_LOADATOMIC: {
3613        // LOADATOMIC: [opty, op, align, vol, ordering, synchscope]
3614       unsigned OpNum = 0;
3615       Value *Op;
3616       if (getValueTypePair(Record, OpNum, NextValueNo, Op) ||
3617           (OpNum + 4 != Record.size() && OpNum + 5 != Record.size()))
3618         return Error("Invalid record");
3619 
3620       Type *Ty = nullptr;
3621       if (OpNum + 5 == Record.size())
3622         Ty = getTypeByID(Record[OpNum++]);
3623 
3624       AtomicOrdering Ordering = GetDecodedOrdering(Record[OpNum+2]);
3625       if (Ordering == NotAtomic || Ordering == Release ||
3626           Ordering == AcquireRelease)
3627         return Error("Invalid record");
3628       if (Ordering != NotAtomic && Record[OpNum] == 0)
3629         return Error("Invalid record");
3630       SynchronizationScope SynchScope = GetDecodedSynchScope(Record[OpNum+3]);
3631 
3632       unsigned Align;
3633       if (std::error_code EC = parseAlignmentValue(Record[OpNum], Align))
3634         return EC;
3635       I = new LoadInst(Op, "", Record[OpNum+1], Align, Ordering, SynchScope);
3636 
3637       (void)Ty;
3638       assert((!Ty || Ty == I->getType()) &&
3639              "Explicit type doesn't match pointee type of the first operand");
3640 
3641       InstructionList.push_back(I);
3642       break;
3643     }
3644     case bitc::FUNC_CODE_INST_STORE: { // STORE2:[ptrty, ptr, val, align, vol]
3645       unsigned OpNum = 0;
3646       Value *Val, *Ptr;
3647       if (getValueTypePair(Record, OpNum, NextValueNo, Ptr) ||
3648           popValue(Record, OpNum, NextValueNo,
3649                     cast<PointerType>(Ptr->getType())->getElementType(), Val) ||
3650           OpNum+2 != Record.size())
3651         return Error("Invalid record");
3652       unsigned Align;
3653       if (std::error_code EC = parseAlignmentValue(Record[OpNum], Align))
3654         return EC;
3655       I = new StoreInst(Val, Ptr, Record[OpNum+1], Align);
3656       InstructionList.push_back(I);
3657       break;
3658     }
3659     case bitc::FUNC_CODE_INST_STOREATOMIC: {
3660       // STOREATOMIC: [ptrty, ptr, val, align, vol, ordering, synchscope]
3661       unsigned OpNum = 0;
3662       Value *Val, *Ptr;
3663       if (getValueTypePair(Record, OpNum, NextValueNo, Ptr) ||
3664           popValue(Record, OpNum, NextValueNo,
3665                     cast<PointerType>(Ptr->getType())->getElementType(), Val) ||
3666           OpNum+4 != Record.size())
3667         return Error("Invalid record");
3668 
3669       AtomicOrdering Ordering = GetDecodedOrdering(Record[OpNum+2]);
3670       if (Ordering == NotAtomic || Ordering == Acquire ||
3671           Ordering == AcquireRelease)
3672         return Error("Invalid record");
3673       SynchronizationScope SynchScope = GetDecodedSynchScope(Record[OpNum+3]);
3674       if (Ordering != NotAtomic && Record[OpNum] == 0)
3675         return Error("Invalid record");
3676 
3677       unsigned Align;
3678       if (std::error_code EC = parseAlignmentValue(Record[OpNum], Align))
3679         return EC;
3680       I = new StoreInst(Val, Ptr, Record[OpNum+1], Align, Ordering, SynchScope);
3681       InstructionList.push_back(I);
3682       break;
3683     }
3684     case bitc::FUNC_CODE_INST_CMPXCHG: {
3685       // CMPXCHG:[ptrty, ptr, cmp, new, vol, successordering, synchscope,
3686       //          failureordering?, isweak?]
3687       unsigned OpNum = 0;
3688       Value *Ptr, *Cmp, *New;
3689       if (getValueTypePair(Record, OpNum, NextValueNo, Ptr) ||
3690           popValue(Record, OpNum, NextValueNo,
3691                     cast<PointerType>(Ptr->getType())->getElementType(), Cmp) ||
3692           popValue(Record, OpNum, NextValueNo,
3693                     cast<PointerType>(Ptr->getType())->getElementType(), New) ||
3694           (Record.size() < OpNum + 3 || Record.size() > OpNum + 5))
3695         return Error("Invalid record");
3696       AtomicOrdering SuccessOrdering = GetDecodedOrdering(Record[OpNum+1]);
3697       if (SuccessOrdering == NotAtomic || SuccessOrdering == Unordered)
3698         return Error("Invalid record");
3699       SynchronizationScope SynchScope = GetDecodedSynchScope(Record[OpNum+2]);
3700 
3701       AtomicOrdering FailureOrdering;
3702       if (Record.size() < 7)
3703         FailureOrdering =
3704             AtomicCmpXchgInst::getStrongestFailureOrdering(SuccessOrdering);
3705       else
3706         FailureOrdering = GetDecodedOrdering(Record[OpNum+3]);
3707 
3708       I = new AtomicCmpXchgInst(Ptr, Cmp, New, SuccessOrdering, FailureOrdering,
3709                                 SynchScope);
3710       cast<AtomicCmpXchgInst>(I)->setVolatile(Record[OpNum]);
3711 
3712       if (Record.size() < 8) {
3713         // Before weak cmpxchgs existed, the instruction simply returned the
3714         // value loaded from memory, so bitcode files from that era will be
3715         // expecting the first component of a modern cmpxchg.
3716         CurBB->getInstList().push_back(I);
3717         I = ExtractValueInst::Create(I, 0);
3718       } else {
3719         cast<AtomicCmpXchgInst>(I)->setWeak(Record[OpNum+4]);
3720       }
3721 
3722       InstructionList.push_back(I);
3723       break;
3724     }
3725     case bitc::FUNC_CODE_INST_ATOMICRMW: {
3726       // ATOMICRMW:[ptrty, ptr, val, op, vol, ordering, synchscope]
3727       unsigned OpNum = 0;
3728       Value *Ptr, *Val;
3729       if (getValueTypePair(Record, OpNum, NextValueNo, Ptr) ||
3730           popValue(Record, OpNum, NextValueNo,
3731                     cast<PointerType>(Ptr->getType())->getElementType(), Val) ||
3732           OpNum+4 != Record.size())
3733         return Error("Invalid record");
3734       AtomicRMWInst::BinOp Operation = GetDecodedRMWOperation(Record[OpNum]);
3735       if (Operation < AtomicRMWInst::FIRST_BINOP ||
3736           Operation > AtomicRMWInst::LAST_BINOP)
3737         return Error("Invalid record");
3738       AtomicOrdering Ordering = GetDecodedOrdering(Record[OpNum+2]);
3739       if (Ordering == NotAtomic || Ordering == Unordered)
3740         return Error("Invalid record");
3741       SynchronizationScope SynchScope = GetDecodedSynchScope(Record[OpNum+3]);
3742       I = new AtomicRMWInst(Operation, Ptr, Val, Ordering, SynchScope);
3743       cast<AtomicRMWInst>(I)->setVolatile(Record[OpNum+1]);
3744       InstructionList.push_back(I);
3745       break;
3746     }
3747     case bitc::FUNC_CODE_INST_FENCE: { // FENCE:[ordering, synchscope]
3748       if (2 != Record.size())
3749         return Error("Invalid record");
3750       AtomicOrdering Ordering = GetDecodedOrdering(Record[0]);
3751       if (Ordering == NotAtomic || Ordering == Unordered ||
3752           Ordering == Monotonic)
3753         return Error("Invalid record");
3754       SynchronizationScope SynchScope = GetDecodedSynchScope(Record[1]);
3755       I = new FenceInst(Context, Ordering, SynchScope);
3756       InstructionList.push_back(I);
3757       break;
3758     }
3759     case bitc::FUNC_CODE_INST_CALL: {
3760       // CALL: [paramattrs, cc, fnty, fnid, arg0, arg1...]
3761       if (Record.size() < 3)
3762         return Error("Invalid record");
3763 
3764       AttributeSet PAL = getAttributes(Record[0]);
3765       unsigned CCInfo = Record[1];
3766 
3767       unsigned OpNum = 2;
3768       Value *Callee;
3769       if (getValueTypePair(Record, OpNum, NextValueNo, Callee))
3770         return Error("Invalid record");
3771 
3772       PointerType *OpTy = dyn_cast<PointerType>(Callee->getType());
3773       FunctionType *FTy = nullptr;
3774       if (OpTy) FTy = dyn_cast<FunctionType>(OpTy->getElementType());
3775       if (!FTy || Record.size() < FTy->getNumParams()+OpNum)
3776         return Error("Invalid record");
3777 
3778       SmallVector<Value*, 16> Args;
3779       // Read the fixed params.
3780       for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i, ++OpNum) {
3781         if (FTy->getParamType(i)->isLabelTy())
3782           Args.push_back(getBasicBlock(Record[OpNum]));
3783         else
3784           Args.push_back(getValue(Record, OpNum, NextValueNo,
3785                                   FTy->getParamType(i)));
3786         if (!Args.back())
3787           return Error("Invalid record");
3788       }
3789 
3790       // Read type/value pairs for varargs params.
3791       if (!FTy->isVarArg()) {
3792         if (OpNum != Record.size())
3793           return Error("Invalid record");
3794       } else {
3795         while (OpNum != Record.size()) {
3796           Value *Op;
3797           if (getValueTypePair(Record, OpNum, NextValueNo, Op))
3798             return Error("Invalid record");
3799           Args.push_back(Op);
3800         }
3801       }
3802 
3803       I = CallInst::Create(Callee, Args);
3804       InstructionList.push_back(I);
3805       cast<CallInst>(I)->setCallingConv(
3806           static_cast<CallingConv::ID>((~(1U << 14) & CCInfo) >> 1));
3807       CallInst::TailCallKind TCK = CallInst::TCK_None;
3808       if (CCInfo & 1)
3809         TCK = CallInst::TCK_Tail;
3810       if (CCInfo & (1 << 14))
3811         TCK = CallInst::TCK_MustTail;
3812       cast<CallInst>(I)->setTailCallKind(TCK);
3813       cast<CallInst>(I)->setAttributes(PAL);
3814       break;
3815     }
3816     case bitc::FUNC_CODE_INST_VAARG: { // VAARG: [valistty, valist, instty]
3817       if (Record.size() < 3)
3818         return Error("Invalid record");
3819       Type *OpTy = getTypeByID(Record[0]);
3820       Value *Op = getValue(Record, 1, NextValueNo, OpTy);
3821       Type *ResTy = getTypeByID(Record[2]);
3822       if (!OpTy || !Op || !ResTy)
3823         return Error("Invalid record");
3824       I = new VAArgInst(Op, ResTy);
3825       InstructionList.push_back(I);
3826       break;
3827     }
3828     }
3829 
3830     // Add instruction to end of current BB.  If there is no current BB, reject
3831     // this file.
3832     if (!CurBB) {
3833       delete I;
3834       return Error("Invalid instruction with no BB");
3835     }
3836     CurBB->getInstList().push_back(I);
3837 
3838     // If this was a terminator instruction, move to the next block.
3839     if (isa<TerminatorInst>(I)) {
3840       ++CurBBNo;
3841       CurBB = CurBBNo < FunctionBBs.size() ? FunctionBBs[CurBBNo] : nullptr;
3842     }
3843 
3844     // Non-void values get registered in the value table for future use.
3845     if (I && !I->getType()->isVoidTy())
3846       ValueList.AssignValue(I, NextValueNo++);
3847   }
3848 
3849 OutOfRecordLoop:
3850 
3851   // Check the function list for unresolved values.
3852   if (Argument *A = dyn_cast<Argument>(ValueList.back())) {
3853     if (!A->getParent()) {
3854       // We found at least one unresolved value.  Nuke them all to avoid leaks.
3855       for (unsigned i = ModuleValueListSize, e = ValueList.size(); i != e; ++i){
3856         if ((A = dyn_cast_or_null<Argument>(ValueList[i])) && !A->getParent()) {
3857           A->replaceAllUsesWith(UndefValue::get(A->getType()));
3858           delete A;
3859         }
3860       }
3861       return Error("Never resolved value found in function");
3862     }
3863   }
3864 
3865   // FIXME: Check for unresolved forward-declared metadata references
3866   // and clean up leaks.
3867 
3868   // Trim the value list down to the size it was before we parsed this function.
3869   ValueList.shrinkTo(ModuleValueListSize);
3870   MDValueList.shrinkTo(ModuleMDValueListSize);
3871   std::vector<BasicBlock*>().swap(FunctionBBs);
3872   return std::error_code();
3873 }
3874 
3875 /// Find the function body in the bitcode stream
3876 std::error_code BitcodeReader::FindFunctionInStream(
3877     Function *F,
3878     DenseMap<Function *, uint64_t>::iterator DeferredFunctionInfoIterator) {
3879   while (DeferredFunctionInfoIterator->second == 0) {
3880     if (Stream.AtEndOfStream())
3881       return Error("Could not find function in stream");
3882     // ParseModule will parse the next body in the stream and set its
3883     // position in the DeferredFunctionInfo map.
3884     if (std::error_code EC = ParseModule(true))
3885       return EC;
3886   }
3887   return std::error_code();
3888 }
3889 
3890 //===----------------------------------------------------------------------===//
3891 // GVMaterializer implementation
3892 //===----------------------------------------------------------------------===//
3893 
3894 void BitcodeReader::releaseBuffer() { Buffer.release(); }
3895 
3896 std::error_code BitcodeReader::materialize(GlobalValue *GV) {
3897   Function *F = dyn_cast<Function>(GV);
3898   // If it's not a function or is already material, ignore the request.
3899   if (!F || !F->isMaterializable())
3900     return std::error_code();
3901 
3902   DenseMap<Function*, uint64_t>::iterator DFII = DeferredFunctionInfo.find(F);
3903   assert(DFII != DeferredFunctionInfo.end() && "Deferred function not found!");
3904   // If its position is recorded as 0, its body is somewhere in the stream
3905   // but we haven't seen it yet.
3906   if (DFII->second == 0 && LazyStreamer)
3907     if (std::error_code EC = FindFunctionInStream(F, DFII))
3908       return EC;
3909 
3910   // Move the bit stream to the saved position of the deferred function body.
3911   Stream.JumpToBit(DFII->second);
3912 
3913   if (std::error_code EC = ParseFunctionBody(F))
3914     return EC;
3915   F->setIsMaterializable(false);
3916 
3917   // Upgrade any old intrinsic calls in the function.
3918   for (UpgradedIntrinsicMap::iterator I = UpgradedIntrinsics.begin(),
3919        E = UpgradedIntrinsics.end(); I != E; ++I) {
3920     if (I->first != I->second) {
3921       for (auto UI = I->first->user_begin(), UE = I->first->user_end();
3922            UI != UE;) {
3923         if (CallInst* CI = dyn_cast<CallInst>(*UI++))
3924           UpgradeIntrinsicCall(CI, I->second);
3925       }
3926     }
3927   }
3928 
3929   // Bring in any functions that this function forward-referenced via
3930   // blockaddresses.
3931   return materializeForwardReferencedFunctions();
3932 }
3933 
3934 bool BitcodeReader::isDematerializable(const GlobalValue *GV) const {
3935   const Function *F = dyn_cast<Function>(GV);
3936   if (!F || F->isDeclaration())
3937     return false;
3938 
3939   // Dematerializing F would leave dangling references that wouldn't be
3940   // reconnected on re-materialization.
3941   if (BlockAddressesTaken.count(F))
3942     return false;
3943 
3944   return DeferredFunctionInfo.count(const_cast<Function*>(F));
3945 }
3946 
3947 void BitcodeReader::Dematerialize(GlobalValue *GV) {
3948   Function *F = dyn_cast<Function>(GV);
3949   // If this function isn't dematerializable, this is a noop.
3950   if (!F || !isDematerializable(F))
3951     return;
3952 
3953   assert(DeferredFunctionInfo.count(F) && "No info to read function later?");
3954 
3955   // Just forget the function body, we can remat it later.
3956   F->dropAllReferences();
3957   F->setIsMaterializable(true);
3958 }
3959 
3960 std::error_code BitcodeReader::MaterializeModule(Module *M) {
3961   assert(M == TheModule &&
3962          "Can only Materialize the Module this BitcodeReader is attached to.");
3963 
3964   // Promise to materialize all forward references.
3965   WillMaterializeAllForwardRefs = true;
3966 
3967   // Iterate over the module, deserializing any functions that are still on
3968   // disk.
3969   for (Module::iterator F = TheModule->begin(), E = TheModule->end();
3970        F != E; ++F) {
3971     if (std::error_code EC = materialize(F))
3972       return EC;
3973   }
3974   // At this point, if there are any function bodies, the current bit is
3975   // pointing to the END_BLOCK record after them. Now make sure the rest
3976   // of the bits in the module have been read.
3977   if (NextUnreadBit)
3978     ParseModule(true);
3979 
3980   // Check that all block address forward references got resolved (as we
3981   // promised above).
3982   if (!BasicBlockFwdRefs.empty())
3983     return Error("Never resolved function from blockaddress");
3984 
3985   // Upgrade any intrinsic calls that slipped through (should not happen!) and
3986   // delete the old functions to clean up. We can't do this unless the entire
3987   // module is materialized because there could always be another function body
3988   // with calls to the old function.
3989   for (std::vector<std::pair<Function*, Function*> >::iterator I =
3990        UpgradedIntrinsics.begin(), E = UpgradedIntrinsics.end(); I != E; ++I) {
3991     if (I->first != I->second) {
3992       for (auto UI = I->first->user_begin(), UE = I->first->user_end();
3993            UI != UE;) {
3994         if (CallInst* CI = dyn_cast<CallInst>(*UI++))
3995           UpgradeIntrinsicCall(CI, I->second);
3996       }
3997       if (!I->first->use_empty())
3998         I->first->replaceAllUsesWith(I->second);
3999       I->first->eraseFromParent();
4000     }
4001   }
4002   std::vector<std::pair<Function*, Function*> >().swap(UpgradedIntrinsics);
4003 
4004   for (unsigned I = 0, E = InstsWithTBAATag.size(); I < E; I++)
4005     UpgradeInstWithTBAATag(InstsWithTBAATag[I]);
4006 
4007   UpgradeDebugInfo(*M);
4008   return std::error_code();
4009 }
4010 
4011 std::vector<StructType *> BitcodeReader::getIdentifiedStructTypes() const {
4012   return IdentifiedStructTypes;
4013 }
4014 
4015 std::error_code BitcodeReader::InitStream() {
4016   if (LazyStreamer)
4017     return InitLazyStream();
4018   return InitStreamFromBuffer();
4019 }
4020 
4021 std::error_code BitcodeReader::InitStreamFromBuffer() {
4022   const unsigned char *BufPtr = (const unsigned char*)Buffer->getBufferStart();
4023   const unsigned char *BufEnd = BufPtr+Buffer->getBufferSize();
4024 
4025   if (Buffer->getBufferSize() & 3)
4026     return Error("Invalid bitcode signature");
4027 
4028   // If we have a wrapper header, parse it and ignore the non-bc file contents.
4029   // The magic number is 0x0B17C0DE stored in little endian.
4030   if (isBitcodeWrapper(BufPtr, BufEnd))
4031     if (SkipBitcodeWrapperHeader(BufPtr, BufEnd, true))
4032       return Error("Invalid bitcode wrapper header");
4033 
4034   StreamFile.reset(new BitstreamReader(BufPtr, BufEnd));
4035   Stream.init(&*StreamFile);
4036 
4037   return std::error_code();
4038 }
4039 
4040 std::error_code BitcodeReader::InitLazyStream() {
4041   // Check and strip off the bitcode wrapper; BitstreamReader expects never to
4042   // see it.
4043   auto OwnedBytes = llvm::make_unique<StreamingMemoryObject>(LazyStreamer);
4044   StreamingMemoryObject &Bytes = *OwnedBytes;
4045   StreamFile = llvm::make_unique<BitstreamReader>(std::move(OwnedBytes));
4046   Stream.init(&*StreamFile);
4047 
4048   unsigned char buf[16];
4049   if (Bytes.readBytes(buf, 16, 0) != 16)
4050     return Error("Invalid bitcode signature");
4051 
4052   if (!isBitcode(buf, buf + 16))
4053     return Error("Invalid bitcode signature");
4054 
4055   if (isBitcodeWrapper(buf, buf + 4)) {
4056     const unsigned char *bitcodeStart = buf;
4057     const unsigned char *bitcodeEnd = buf + 16;
4058     SkipBitcodeWrapperHeader(bitcodeStart, bitcodeEnd, false);
4059     Bytes.dropLeadingBytes(bitcodeStart - buf);
4060     Bytes.setKnownObjectSize(bitcodeEnd - bitcodeStart);
4061   }
4062   return std::error_code();
4063 }
4064 
4065 namespace {
4066 class BitcodeErrorCategoryType : public std::error_category {
4067   const char *name() const LLVM_NOEXCEPT override {
4068     return "llvm.bitcode";
4069   }
4070   std::string message(int IE) const override {
4071     BitcodeError E = static_cast<BitcodeError>(IE);
4072     switch (E) {
4073     case BitcodeError::InvalidBitcodeSignature:
4074       return "Invalid bitcode signature";
4075     case BitcodeError::CorruptedBitcode:
4076       return "Corrupted bitcode";
4077     }
4078     llvm_unreachable("Unknown error type!");
4079   }
4080 };
4081 }
4082 
4083 static ManagedStatic<BitcodeErrorCategoryType> ErrorCategory;
4084 
4085 const std::error_category &llvm::BitcodeErrorCategory() {
4086   return *ErrorCategory;
4087 }
4088 
4089 //===----------------------------------------------------------------------===//
4090 // External interface
4091 //===----------------------------------------------------------------------===//
4092 
4093 /// \brief Get a lazy one-at-time loading module from bitcode.
4094 ///
4095 /// This isn't always used in a lazy context.  In particular, it's also used by
4096 /// \a parseBitcodeFile().  If this is truly lazy, then we need to eagerly pull
4097 /// in forward-referenced functions from block address references.
4098 ///
4099 /// \param[in] WillMaterializeAll Set to \c true if the caller promises to
4100 /// materialize everything -- in particular, if this isn't truly lazy.
4101 static ErrorOr<Module *>
4102 getLazyBitcodeModuleImpl(std::unique_ptr<MemoryBuffer> &&Buffer,
4103                          LLVMContext &Context, bool WillMaterializeAll,
4104                          DiagnosticHandlerFunction DiagnosticHandler) {
4105   Module *M = new Module(Buffer->getBufferIdentifier(), Context);
4106   BitcodeReader *R =
4107       new BitcodeReader(Buffer.get(), Context, DiagnosticHandler);
4108   M->setMaterializer(R);
4109 
4110   auto cleanupOnError = [&](std::error_code EC) {
4111     R->releaseBuffer(); // Never take ownership on error.
4112     delete M;  // Also deletes R.
4113     return EC;
4114   };
4115 
4116   if (std::error_code EC = R->ParseBitcodeInto(M))
4117     return cleanupOnError(EC);
4118 
4119   if (!WillMaterializeAll)
4120     // Resolve forward references from blockaddresses.
4121     if (std::error_code EC = R->materializeForwardReferencedFunctions())
4122       return cleanupOnError(EC);
4123 
4124   Buffer.release(); // The BitcodeReader owns it now.
4125   return M;
4126 }
4127 
4128 ErrorOr<Module *>
4129 llvm::getLazyBitcodeModule(std::unique_ptr<MemoryBuffer> &&Buffer,
4130                            LLVMContext &Context,
4131                            DiagnosticHandlerFunction DiagnosticHandler) {
4132   return getLazyBitcodeModuleImpl(std::move(Buffer), Context, false,
4133                                   DiagnosticHandler);
4134 }
4135 
4136 ErrorOr<std::unique_ptr<Module>>
4137 llvm::getStreamedBitcodeModule(StringRef Name, DataStreamer *Streamer,
4138                                LLVMContext &Context,
4139                                DiagnosticHandlerFunction DiagnosticHandler) {
4140   std::unique_ptr<Module> M = make_unique<Module>(Name, Context);
4141   BitcodeReader *R = new BitcodeReader(Streamer, Context, DiagnosticHandler);
4142   M->setMaterializer(R);
4143   if (std::error_code EC = R->ParseBitcodeInto(M.get()))
4144     return EC;
4145   return std::move(M);
4146 }
4147 
4148 ErrorOr<Module *>
4149 llvm::parseBitcodeFile(MemoryBufferRef Buffer, LLVMContext &Context,
4150                        DiagnosticHandlerFunction DiagnosticHandler) {
4151   std::unique_ptr<MemoryBuffer> Buf = MemoryBuffer::getMemBuffer(Buffer, false);
4152   ErrorOr<Module *> ModuleOrErr = getLazyBitcodeModuleImpl(
4153       std::move(Buf), Context, true, DiagnosticHandler);
4154   if (!ModuleOrErr)
4155     return ModuleOrErr;
4156   Module *M = ModuleOrErr.get();
4157   // Read in the entire module, and destroy the BitcodeReader.
4158   if (std::error_code EC = M->materializeAllPermanently()) {
4159     delete M;
4160     return EC;
4161   }
4162 
4163   // TODO: Restore the use-lists to the in-memory state when the bitcode was
4164   // written.  We must defer until the Module has been fully materialized.
4165 
4166   return M;
4167 }
4168 
4169 std::string
4170 llvm::getBitcodeTargetTriple(MemoryBufferRef Buffer, LLVMContext &Context,
4171                              DiagnosticHandlerFunction DiagnosticHandler) {
4172   std::unique_ptr<MemoryBuffer> Buf = MemoryBuffer::getMemBuffer(Buffer, false);
4173   auto R = llvm::make_unique<BitcodeReader>(Buf.release(), Context,
4174                                             DiagnosticHandler);
4175   ErrorOr<std::string> Triple = R->parseTriple();
4176   if (Triple.getError())
4177     return "";
4178   return Triple.get();
4179 }
4180