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/SmallString.h"
13 #include "llvm/ADT/SmallVector.h"
14 #include "llvm/ADT/Triple.h"
15 #include "llvm/Bitcode/LLVMBitCodes.h"
16 #include "llvm/IR/AutoUpgrade.h"
17 #include "llvm/IR/Constants.h"
18 #include "llvm/IR/DebugInfoMetadata.h"
19 #include "llvm/IR/DerivedTypes.h"
20 #include "llvm/IR/DiagnosticPrinter.h"
21 #include "llvm/IR/InlineAsm.h"
22 #include "llvm/IR/IntrinsicInst.h"
23 #include "llvm/IR/LLVMContext.h"
24 #include "llvm/IR/Module.h"
25 #include "llvm/IR/OperandTraits.h"
26 #include "llvm/IR/Operator.h"
27 #include "llvm/Support/DataStream.h"
28 #include "llvm/Support/ManagedStatic.h"
29 #include "llvm/Support/MathExtras.h"
30 #include "llvm/Support/MemoryBuffer.h"
31 #include "llvm/Support/raw_ostream.h"
32 
33 using namespace llvm;
34 
35 enum {
36   SWITCH_INST_MAGIC = 0x4B5 // May 2012 => 1205 => Hex
37 };
38 
39 BitcodeDiagnosticInfo::BitcodeDiagnosticInfo(std::error_code EC,
40                                              DiagnosticSeverity Severity,
41                                              const Twine &Msg)
42     : DiagnosticInfo(DK_Bitcode, Severity), Msg(Msg), EC(EC) {}
43 
44 void BitcodeDiagnosticInfo::print(DiagnosticPrinter &DP) const { DP << Msg; }
45 
46 static std::error_code Error(DiagnosticHandlerFunction DiagnosticHandler,
47                              std::error_code EC, const Twine &Message) {
48   BitcodeDiagnosticInfo DI(EC, DS_Error, Message);
49   DiagnosticHandler(DI);
50   return EC;
51 }
52 
53 static std::error_code Error(DiagnosticHandlerFunction DiagnosticHandler,
54                              std::error_code EC) {
55   return Error(DiagnosticHandler, EC, EC.message());
56 }
57 
58 std::error_code BitcodeReader::Error(BitcodeError E, const Twine &Message) {
59   return ::Error(DiagnosticHandler, make_error_code(E), Message);
60 }
61 
62 std::error_code BitcodeReader::Error(const Twine &Message) {
63   return ::Error(DiagnosticHandler,
64                  make_error_code(BitcodeError::CorruptedBitcode), Message);
65 }
66 
67 std::error_code BitcodeReader::Error(BitcodeError E) {
68   return ::Error(DiagnosticHandler, make_error_code(E));
69 }
70 
71 static DiagnosticHandlerFunction getDiagHandler(DiagnosticHandlerFunction F,
72                                                 LLVMContext &C) {
73   if (F)
74     return F;
75   return [&C](const DiagnosticInfo &DI) { C.diagnose(DI); };
76 }
77 
78 BitcodeReader::BitcodeReader(MemoryBuffer *buffer, LLVMContext &C,
79                              DiagnosticHandlerFunction DiagnosticHandler)
80     : Context(C), DiagnosticHandler(getDiagHandler(DiagnosticHandler, C)),
81       TheModule(nullptr), Buffer(buffer), LazyStreamer(nullptr),
82       NextUnreadBit(0), SeenValueSymbolTable(false), ValueList(C),
83       MDValueList(C), SeenFirstFunctionBody(false), UseRelativeIDs(false),
84       WillMaterializeAllForwardRefs(false) {}
85 
86 BitcodeReader::BitcodeReader(DataStreamer *streamer, LLVMContext &C,
87                              DiagnosticHandlerFunction DiagnosticHandler)
88     : Context(C), DiagnosticHandler(getDiagHandler(DiagnosticHandler, C)),
89       TheModule(nullptr), Buffer(nullptr), LazyStreamer(streamer),
90       NextUnreadBit(0), SeenValueSymbolTable(false), ValueList(C),
91       MDValueList(C), SeenFirstFunctionBody(false), UseRelativeIDs(false),
92       WillMaterializeAllForwardRefs(false) {}
93 
94 std::error_code BitcodeReader::materializeForwardReferencedFunctions() {
95   if (WillMaterializeAllForwardRefs)
96     return std::error_code();
97 
98   // Prevent recursion.
99   WillMaterializeAllForwardRefs = true;
100 
101   while (!BasicBlockFwdRefQueue.empty()) {
102     Function *F = BasicBlockFwdRefQueue.front();
103     BasicBlockFwdRefQueue.pop_front();
104     assert(F && "Expected valid function");
105     if (!BasicBlockFwdRefs.count(F))
106       // Already materialized.
107       continue;
108 
109     // Check for a function that isn't materializable to prevent an infinite
110     // loop.  When parsing a blockaddress stored in a global variable, there
111     // isn't a trivial way to check if a function will have a body without a
112     // linear search through FunctionsWithBodies, so just check it here.
113     if (!F->isMaterializable())
114       return Error("Never resolved function from blockaddress");
115 
116     // Try to materialize F.
117     if (std::error_code EC = materialize(F))
118       return EC;
119   }
120   assert(BasicBlockFwdRefs.empty() && "Function missing from queue");
121 
122   // Reset state.
123   WillMaterializeAllForwardRefs = false;
124   return std::error_code();
125 }
126 
127 void BitcodeReader::FreeState() {
128   Buffer = nullptr;
129   std::vector<Type*>().swap(TypeList);
130   ValueList.clear();
131   MDValueList.clear();
132   std::vector<Comdat *>().swap(ComdatList);
133 
134   std::vector<AttributeSet>().swap(MAttributes);
135   std::vector<BasicBlock*>().swap(FunctionBBs);
136   std::vector<Function*>().swap(FunctionsWithBodies);
137   DeferredFunctionInfo.clear();
138   MDKindMap.clear();
139 
140   assert(BasicBlockFwdRefs.empty() && "Unresolved blockaddress fwd references");
141   BasicBlockFwdRefQueue.clear();
142 }
143 
144 //===----------------------------------------------------------------------===//
145 //  Helper functions to implement forward reference resolution, etc.
146 //===----------------------------------------------------------------------===//
147 
148 /// ConvertToString - Convert a string from a record into an std::string, return
149 /// true on failure.
150 template<typename StrTy>
151 static bool ConvertToString(ArrayRef<uint64_t> Record, unsigned Idx,
152                             StrTy &Result) {
153   if (Idx > Record.size())
154     return true;
155 
156   for (unsigned i = Idx, e = Record.size(); i != e; ++i)
157     Result += (char)Record[i];
158   return false;
159 }
160 
161 static bool hasImplicitComdat(size_t Val) {
162   switch (Val) {
163   default:
164     return false;
165   case 1:  // Old WeakAnyLinkage
166   case 4:  // Old LinkOnceAnyLinkage
167   case 10: // Old WeakODRLinkage
168   case 11: // Old LinkOnceODRLinkage
169     return true;
170   }
171 }
172 
173 static GlobalValue::LinkageTypes getDecodedLinkage(unsigned Val) {
174   switch (Val) {
175   default: // Map unknown/new linkages to external
176   case 0:
177     return GlobalValue::ExternalLinkage;
178   case 2:
179     return GlobalValue::AppendingLinkage;
180   case 3:
181     return GlobalValue::InternalLinkage;
182   case 5:
183     return GlobalValue::ExternalLinkage; // Obsolete DLLImportLinkage
184   case 6:
185     return GlobalValue::ExternalLinkage; // Obsolete DLLExportLinkage
186   case 7:
187     return GlobalValue::ExternalWeakLinkage;
188   case 8:
189     return GlobalValue::CommonLinkage;
190   case 9:
191     return GlobalValue::PrivateLinkage;
192   case 12:
193     return GlobalValue::AvailableExternallyLinkage;
194   case 13:
195     return GlobalValue::PrivateLinkage; // Obsolete LinkerPrivateLinkage
196   case 14:
197     return GlobalValue::PrivateLinkage; // Obsolete LinkerPrivateWeakLinkage
198   case 15:
199     return GlobalValue::ExternalLinkage; // Obsolete LinkOnceODRAutoHideLinkage
200   case 1: // Old value with implicit comdat.
201   case 16:
202     return GlobalValue::WeakAnyLinkage;
203   case 10: // Old value with implicit comdat.
204   case 17:
205     return GlobalValue::WeakODRLinkage;
206   case 4: // Old value with implicit comdat.
207   case 18:
208     return GlobalValue::LinkOnceAnyLinkage;
209   case 11: // Old value with implicit comdat.
210   case 19:
211     return GlobalValue::LinkOnceODRLinkage;
212   }
213 }
214 
215 static GlobalValue::VisibilityTypes GetDecodedVisibility(unsigned Val) {
216   switch (Val) {
217   default: // Map unknown visibilities to default.
218   case 0: return GlobalValue::DefaultVisibility;
219   case 1: return GlobalValue::HiddenVisibility;
220   case 2: return GlobalValue::ProtectedVisibility;
221   }
222 }
223 
224 static GlobalValue::DLLStorageClassTypes
225 GetDecodedDLLStorageClass(unsigned Val) {
226   switch (Val) {
227   default: // Map unknown values to default.
228   case 0: return GlobalValue::DefaultStorageClass;
229   case 1: return GlobalValue::DLLImportStorageClass;
230   case 2: return GlobalValue::DLLExportStorageClass;
231   }
232 }
233 
234 static GlobalVariable::ThreadLocalMode GetDecodedThreadLocalMode(unsigned Val) {
235   switch (Val) {
236     case 0: return GlobalVariable::NotThreadLocal;
237     default: // Map unknown non-zero value to general dynamic.
238     case 1: return GlobalVariable::GeneralDynamicTLSModel;
239     case 2: return GlobalVariable::LocalDynamicTLSModel;
240     case 3: return GlobalVariable::InitialExecTLSModel;
241     case 4: return GlobalVariable::LocalExecTLSModel;
242   }
243 }
244 
245 static int GetDecodedCastOpcode(unsigned Val) {
246   switch (Val) {
247   default: return -1;
248   case bitc::CAST_TRUNC   : return Instruction::Trunc;
249   case bitc::CAST_ZEXT    : return Instruction::ZExt;
250   case bitc::CAST_SEXT    : return Instruction::SExt;
251   case bitc::CAST_FPTOUI  : return Instruction::FPToUI;
252   case bitc::CAST_FPTOSI  : return Instruction::FPToSI;
253   case bitc::CAST_UITOFP  : return Instruction::UIToFP;
254   case bitc::CAST_SITOFP  : return Instruction::SIToFP;
255   case bitc::CAST_FPTRUNC : return Instruction::FPTrunc;
256   case bitc::CAST_FPEXT   : return Instruction::FPExt;
257   case bitc::CAST_PTRTOINT: return Instruction::PtrToInt;
258   case bitc::CAST_INTTOPTR: return Instruction::IntToPtr;
259   case bitc::CAST_BITCAST : return Instruction::BitCast;
260   case bitc::CAST_ADDRSPACECAST: return Instruction::AddrSpaceCast;
261   }
262 }
263 static int GetDecodedBinaryOpcode(unsigned Val, Type *Ty) {
264   switch (Val) {
265   default: return -1;
266   case bitc::BINOP_ADD:
267     return Ty->isFPOrFPVectorTy() ? Instruction::FAdd : Instruction::Add;
268   case bitc::BINOP_SUB:
269     return Ty->isFPOrFPVectorTy() ? Instruction::FSub : Instruction::Sub;
270   case bitc::BINOP_MUL:
271     return Ty->isFPOrFPVectorTy() ? Instruction::FMul : Instruction::Mul;
272   case bitc::BINOP_UDIV: return Instruction::UDiv;
273   case bitc::BINOP_SDIV:
274     return Ty->isFPOrFPVectorTy() ? Instruction::FDiv : Instruction::SDiv;
275   case bitc::BINOP_UREM: return Instruction::URem;
276   case bitc::BINOP_SREM:
277     return Ty->isFPOrFPVectorTy() ? Instruction::FRem : Instruction::SRem;
278   case bitc::BINOP_SHL:  return Instruction::Shl;
279   case bitc::BINOP_LSHR: return Instruction::LShr;
280   case bitc::BINOP_ASHR: return Instruction::AShr;
281   case bitc::BINOP_AND:  return Instruction::And;
282   case bitc::BINOP_OR:   return Instruction::Or;
283   case bitc::BINOP_XOR:  return Instruction::Xor;
284   }
285 }
286 
287 static AtomicRMWInst::BinOp GetDecodedRMWOperation(unsigned Val) {
288   switch (Val) {
289   default: return AtomicRMWInst::BAD_BINOP;
290   case bitc::RMW_XCHG: return AtomicRMWInst::Xchg;
291   case bitc::RMW_ADD: return AtomicRMWInst::Add;
292   case bitc::RMW_SUB: return AtomicRMWInst::Sub;
293   case bitc::RMW_AND: return AtomicRMWInst::And;
294   case bitc::RMW_NAND: return AtomicRMWInst::Nand;
295   case bitc::RMW_OR: return AtomicRMWInst::Or;
296   case bitc::RMW_XOR: return AtomicRMWInst::Xor;
297   case bitc::RMW_MAX: return AtomicRMWInst::Max;
298   case bitc::RMW_MIN: return AtomicRMWInst::Min;
299   case bitc::RMW_UMAX: return AtomicRMWInst::UMax;
300   case bitc::RMW_UMIN: return AtomicRMWInst::UMin;
301   }
302 }
303 
304 static AtomicOrdering GetDecodedOrdering(unsigned Val) {
305   switch (Val) {
306   case bitc::ORDERING_NOTATOMIC: return NotAtomic;
307   case bitc::ORDERING_UNORDERED: return Unordered;
308   case bitc::ORDERING_MONOTONIC: return Monotonic;
309   case bitc::ORDERING_ACQUIRE: return Acquire;
310   case bitc::ORDERING_RELEASE: return Release;
311   case bitc::ORDERING_ACQREL: return AcquireRelease;
312   default: // Map unknown orderings to sequentially-consistent.
313   case bitc::ORDERING_SEQCST: return SequentiallyConsistent;
314   }
315 }
316 
317 static SynchronizationScope GetDecodedSynchScope(unsigned Val) {
318   switch (Val) {
319   case bitc::SYNCHSCOPE_SINGLETHREAD: return SingleThread;
320   default: // Map unknown scopes to cross-thread.
321   case bitc::SYNCHSCOPE_CROSSTHREAD: return CrossThread;
322   }
323 }
324 
325 static Comdat::SelectionKind getDecodedComdatSelectionKind(unsigned Val) {
326   switch (Val) {
327   default: // Map unknown selection kinds to any.
328   case bitc::COMDAT_SELECTION_KIND_ANY:
329     return Comdat::Any;
330   case bitc::COMDAT_SELECTION_KIND_EXACT_MATCH:
331     return Comdat::ExactMatch;
332   case bitc::COMDAT_SELECTION_KIND_LARGEST:
333     return Comdat::Largest;
334   case bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES:
335     return Comdat::NoDuplicates;
336   case bitc::COMDAT_SELECTION_KIND_SAME_SIZE:
337     return Comdat::SameSize;
338   }
339 }
340 
341 static void UpgradeDLLImportExportLinkage(llvm::GlobalValue *GV, unsigned Val) {
342   switch (Val) {
343   case 5: GV->setDLLStorageClass(GlobalValue::DLLImportStorageClass); break;
344   case 6: GV->setDLLStorageClass(GlobalValue::DLLExportStorageClass); break;
345   }
346 }
347 
348 namespace llvm {
349 namespace {
350   /// @brief A class for maintaining the slot number definition
351   /// as a placeholder for the actual definition for forward constants defs.
352   class ConstantPlaceHolder : public ConstantExpr {
353     void operator=(const ConstantPlaceHolder &) = delete;
354   public:
355     // allocate space for exactly one operand
356     void *operator new(size_t s) {
357       return User::operator new(s, 1);
358     }
359     explicit ConstantPlaceHolder(Type *Ty, LLVMContext& Context)
360       : ConstantExpr(Ty, Instruction::UserOp1, &Op<0>(), 1) {
361       Op<0>() = UndefValue::get(Type::getInt32Ty(Context));
362     }
363 
364     /// @brief Methods to support type inquiry through isa, cast, and dyn_cast.
365     static bool classof(const Value *V) {
366       return isa<ConstantExpr>(V) &&
367              cast<ConstantExpr>(V)->getOpcode() == Instruction::UserOp1;
368     }
369 
370 
371     /// Provide fast operand accessors
372     DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
373   };
374 }
375 
376 // FIXME: can we inherit this from ConstantExpr?
377 template <>
378 struct OperandTraits<ConstantPlaceHolder> :
379   public FixedNumOperandTraits<ConstantPlaceHolder, 1> {
380 };
381 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(ConstantPlaceHolder, Value)
382 }
383 
384 
385 void BitcodeReaderValueList::AssignValue(Value *V, unsigned Idx) {
386   if (Idx == size()) {
387     push_back(V);
388     return;
389   }
390 
391   if (Idx >= size())
392     resize(Idx+1);
393 
394   WeakVH &OldV = ValuePtrs[Idx];
395   if (!OldV) {
396     OldV = V;
397     return;
398   }
399 
400   // Handle constants and non-constants (e.g. instrs) differently for
401   // efficiency.
402   if (Constant *PHC = dyn_cast<Constant>(&*OldV)) {
403     ResolveConstants.push_back(std::make_pair(PHC, Idx));
404     OldV = V;
405   } else {
406     // If there was a forward reference to this value, replace it.
407     Value *PrevVal = OldV;
408     OldV->replaceAllUsesWith(V);
409     delete PrevVal;
410   }
411 }
412 
413 
414 Constant *BitcodeReaderValueList::getConstantFwdRef(unsigned Idx,
415                                                     Type *Ty) {
416   if (Idx >= size())
417     resize(Idx + 1);
418 
419   if (Value *V = ValuePtrs[Idx]) {
420     assert(Ty == V->getType() && "Type mismatch in constant table!");
421     return cast<Constant>(V);
422   }
423 
424   // Create and return a placeholder, which will later be RAUW'd.
425   Constant *C = new ConstantPlaceHolder(Ty, Context);
426   ValuePtrs[Idx] = C;
427   return C;
428 }
429 
430 Value *BitcodeReaderValueList::getValueFwdRef(unsigned Idx, Type *Ty) {
431   if (Idx >= size())
432     resize(Idx + 1);
433 
434   if (Value *V = ValuePtrs[Idx]) {
435     assert((!Ty || Ty == V->getType()) && "Type mismatch in value table!");
436     return V;
437   }
438 
439   // No type specified, must be invalid reference.
440   if (!Ty) return nullptr;
441 
442   // Create and return a placeholder, which will later be RAUW'd.
443   Value *V = new Argument(Ty);
444   ValuePtrs[Idx] = V;
445   return V;
446 }
447 
448 /// ResolveConstantForwardRefs - Once all constants are read, this method bulk
449 /// resolves any forward references.  The idea behind this is that we sometimes
450 /// get constants (such as large arrays) which reference *many* forward ref
451 /// constants.  Replacing each of these causes a lot of thrashing when
452 /// building/reuniquing the constant.  Instead of doing this, we look at all the
453 /// uses and rewrite all the place holders at once for any constant that uses
454 /// a placeholder.
455 void BitcodeReaderValueList::ResolveConstantForwardRefs() {
456   // Sort the values by-pointer so that they are efficient to look up with a
457   // binary search.
458   std::sort(ResolveConstants.begin(), ResolveConstants.end());
459 
460   SmallVector<Constant*, 64> NewOps;
461 
462   while (!ResolveConstants.empty()) {
463     Value *RealVal = operator[](ResolveConstants.back().second);
464     Constant *Placeholder = ResolveConstants.back().first;
465     ResolveConstants.pop_back();
466 
467     // Loop over all users of the placeholder, updating them to reference the
468     // new value.  If they reference more than one placeholder, update them all
469     // at once.
470     while (!Placeholder->use_empty()) {
471       auto UI = Placeholder->user_begin();
472       User *U = *UI;
473 
474       // If the using object isn't uniqued, just update the operands.  This
475       // handles instructions and initializers for global variables.
476       if (!isa<Constant>(U) || isa<GlobalValue>(U)) {
477         UI.getUse().set(RealVal);
478         continue;
479       }
480 
481       // Otherwise, we have a constant that uses the placeholder.  Replace that
482       // constant with a new constant that has *all* placeholder uses updated.
483       Constant *UserC = cast<Constant>(U);
484       for (User::op_iterator I = UserC->op_begin(), E = UserC->op_end();
485            I != E; ++I) {
486         Value *NewOp;
487         if (!isa<ConstantPlaceHolder>(*I)) {
488           // Not a placeholder reference.
489           NewOp = *I;
490         } else if (*I == Placeholder) {
491           // Common case is that it just references this one placeholder.
492           NewOp = RealVal;
493         } else {
494           // Otherwise, look up the placeholder in ResolveConstants.
495           ResolveConstantsTy::iterator It =
496             std::lower_bound(ResolveConstants.begin(), ResolveConstants.end(),
497                              std::pair<Constant*, unsigned>(cast<Constant>(*I),
498                                                             0));
499           assert(It != ResolveConstants.end() && It->first == *I);
500           NewOp = operator[](It->second);
501         }
502 
503         NewOps.push_back(cast<Constant>(NewOp));
504       }
505 
506       // Make the new constant.
507       Constant *NewC;
508       if (ConstantArray *UserCA = dyn_cast<ConstantArray>(UserC)) {
509         NewC = ConstantArray::get(UserCA->getType(), NewOps);
510       } else if (ConstantStruct *UserCS = dyn_cast<ConstantStruct>(UserC)) {
511         NewC = ConstantStruct::get(UserCS->getType(), NewOps);
512       } else if (isa<ConstantVector>(UserC)) {
513         NewC = ConstantVector::get(NewOps);
514       } else {
515         assert(isa<ConstantExpr>(UserC) && "Must be a ConstantExpr.");
516         NewC = cast<ConstantExpr>(UserC)->getWithOperands(NewOps);
517       }
518 
519       UserC->replaceAllUsesWith(NewC);
520       UserC->destroyConstant();
521       NewOps.clear();
522     }
523 
524     // Update all ValueHandles, they should be the only users at this point.
525     Placeholder->replaceAllUsesWith(RealVal);
526     delete Placeholder;
527   }
528 }
529 
530 void BitcodeReaderMDValueList::AssignValue(Metadata *MD, unsigned Idx) {
531   if (Idx == size()) {
532     push_back(MD);
533     return;
534   }
535 
536   if (Idx >= size())
537     resize(Idx+1);
538 
539   TrackingMDRef &OldMD = MDValuePtrs[Idx];
540   if (!OldMD) {
541     OldMD.reset(MD);
542     return;
543   }
544 
545   // If there was a forward reference to this value, replace it.
546   TempMDTuple PrevMD(cast<MDTuple>(OldMD.get()));
547   PrevMD->replaceAllUsesWith(MD);
548   --NumFwdRefs;
549 }
550 
551 Metadata *BitcodeReaderMDValueList::getValueFwdRef(unsigned Idx) {
552   if (Idx >= size())
553     resize(Idx + 1);
554 
555   if (Metadata *MD = MDValuePtrs[Idx])
556     return MD;
557 
558   // Track forward refs to be resolved later.
559   if (AnyFwdRefs) {
560     MinFwdRef = std::min(MinFwdRef, Idx);
561     MaxFwdRef = std::max(MaxFwdRef, Idx);
562   } else {
563     AnyFwdRefs = true;
564     MinFwdRef = MaxFwdRef = Idx;
565   }
566   ++NumFwdRefs;
567 
568   // Create and return a placeholder, which will later be RAUW'd.
569   Metadata *MD = MDNode::getTemporary(Context, None).release();
570   MDValuePtrs[Idx].reset(MD);
571   return MD;
572 }
573 
574 void BitcodeReaderMDValueList::tryToResolveCycles() {
575   if (!AnyFwdRefs)
576     // Nothing to do.
577     return;
578 
579   if (NumFwdRefs)
580     // Still forward references... can't resolve cycles.
581     return;
582 
583   // Resolve any cycles.
584   for (unsigned I = MinFwdRef, E = MaxFwdRef + 1; I != E; ++I) {
585     auto &MD = MDValuePtrs[I];
586     auto *N = dyn_cast_or_null<MDNode>(MD);
587     if (!N)
588       continue;
589 
590     assert(!N->isTemporary() && "Unexpected forward reference");
591     N->resolveCycles();
592   }
593 
594   // Make sure we return early again until there's another forward ref.
595   AnyFwdRefs = false;
596 }
597 
598 Type *BitcodeReader::getTypeByID(unsigned ID) {
599   // The type table size is always specified correctly.
600   if (ID >= TypeList.size())
601     return nullptr;
602 
603   if (Type *Ty = TypeList[ID])
604     return Ty;
605 
606   // If we have a forward reference, the only possible case is when it is to a
607   // named struct.  Just create a placeholder for now.
608   return TypeList[ID] = createIdentifiedStructType(Context);
609 }
610 
611 StructType *BitcodeReader::createIdentifiedStructType(LLVMContext &Context,
612                                                       StringRef Name) {
613   auto *Ret = StructType::create(Context, Name);
614   IdentifiedStructTypes.push_back(Ret);
615   return Ret;
616 }
617 
618 StructType *BitcodeReader::createIdentifiedStructType(LLVMContext &Context) {
619   auto *Ret = StructType::create(Context);
620   IdentifiedStructTypes.push_back(Ret);
621   return Ret;
622 }
623 
624 
625 //===----------------------------------------------------------------------===//
626 //  Functions for parsing blocks from the bitcode file
627 //===----------------------------------------------------------------------===//
628 
629 
630 /// \brief This fills an AttrBuilder object with the LLVM attributes that have
631 /// been decoded from the given integer. This function must stay in sync with
632 /// 'encodeLLVMAttributesForBitcode'.
633 static void decodeLLVMAttributesForBitcode(AttrBuilder &B,
634                                            uint64_t EncodedAttrs) {
635   // FIXME: Remove in 4.0.
636 
637   // The alignment is stored as a 16-bit raw value from bits 31--16.  We shift
638   // the bits above 31 down by 11 bits.
639   unsigned Alignment = (EncodedAttrs & (0xffffULL << 16)) >> 16;
640   assert((!Alignment || isPowerOf2_32(Alignment)) &&
641          "Alignment must be a power of two.");
642 
643   if (Alignment)
644     B.addAlignmentAttr(Alignment);
645   B.addRawValue(((EncodedAttrs & (0xfffffULL << 32)) >> 11) |
646                 (EncodedAttrs & 0xffff));
647 }
648 
649 std::error_code BitcodeReader::ParseAttributeBlock() {
650   if (Stream.EnterSubBlock(bitc::PARAMATTR_BLOCK_ID))
651     return Error("Invalid record");
652 
653   if (!MAttributes.empty())
654     return Error("Invalid multiple blocks");
655 
656   SmallVector<uint64_t, 64> Record;
657 
658   SmallVector<AttributeSet, 8> Attrs;
659 
660   // Read all the records.
661   while (1) {
662     BitstreamEntry Entry = Stream.advanceSkippingSubblocks();
663 
664     switch (Entry.Kind) {
665     case BitstreamEntry::SubBlock: // Handled for us already.
666     case BitstreamEntry::Error:
667       return Error("Malformed block");
668     case BitstreamEntry::EndBlock:
669       return std::error_code();
670     case BitstreamEntry::Record:
671       // The interesting case.
672       break;
673     }
674 
675     // Read a record.
676     Record.clear();
677     switch (Stream.readRecord(Entry.ID, Record)) {
678     default:  // Default behavior: ignore.
679       break;
680     case bitc::PARAMATTR_CODE_ENTRY_OLD: { // ENTRY: [paramidx0, attr0, ...]
681       // FIXME: Remove in 4.0.
682       if (Record.size() & 1)
683         return Error("Invalid record");
684 
685       for (unsigned i = 0, e = Record.size(); i != e; i += 2) {
686         AttrBuilder B;
687         decodeLLVMAttributesForBitcode(B, Record[i+1]);
688         Attrs.push_back(AttributeSet::get(Context, Record[i], B));
689       }
690 
691       MAttributes.push_back(AttributeSet::get(Context, Attrs));
692       Attrs.clear();
693       break;
694     }
695     case bitc::PARAMATTR_CODE_ENTRY: { // ENTRY: [attrgrp0, attrgrp1, ...]
696       for (unsigned i = 0, e = Record.size(); i != e; ++i)
697         Attrs.push_back(MAttributeGroups[Record[i]]);
698 
699       MAttributes.push_back(AttributeSet::get(Context, Attrs));
700       Attrs.clear();
701       break;
702     }
703     }
704   }
705 }
706 
707 // Returns Attribute::None on unrecognized codes.
708 static Attribute::AttrKind GetAttrFromCode(uint64_t Code) {
709   switch (Code) {
710   default:
711     return Attribute::None;
712   case bitc::ATTR_KIND_ALIGNMENT:
713     return Attribute::Alignment;
714   case bitc::ATTR_KIND_ALWAYS_INLINE:
715     return Attribute::AlwaysInline;
716   case bitc::ATTR_KIND_BUILTIN:
717     return Attribute::Builtin;
718   case bitc::ATTR_KIND_BY_VAL:
719     return Attribute::ByVal;
720   case bitc::ATTR_KIND_IN_ALLOCA:
721     return Attribute::InAlloca;
722   case bitc::ATTR_KIND_COLD:
723     return Attribute::Cold;
724   case bitc::ATTR_KIND_INLINE_HINT:
725     return Attribute::InlineHint;
726   case bitc::ATTR_KIND_IN_REG:
727     return Attribute::InReg;
728   case bitc::ATTR_KIND_JUMP_TABLE:
729     return Attribute::JumpTable;
730   case bitc::ATTR_KIND_MIN_SIZE:
731     return Attribute::MinSize;
732   case bitc::ATTR_KIND_NAKED:
733     return Attribute::Naked;
734   case bitc::ATTR_KIND_NEST:
735     return Attribute::Nest;
736   case bitc::ATTR_KIND_NO_ALIAS:
737     return Attribute::NoAlias;
738   case bitc::ATTR_KIND_NO_BUILTIN:
739     return Attribute::NoBuiltin;
740   case bitc::ATTR_KIND_NO_CAPTURE:
741     return Attribute::NoCapture;
742   case bitc::ATTR_KIND_NO_DUPLICATE:
743     return Attribute::NoDuplicate;
744   case bitc::ATTR_KIND_NO_IMPLICIT_FLOAT:
745     return Attribute::NoImplicitFloat;
746   case bitc::ATTR_KIND_NO_INLINE:
747     return Attribute::NoInline;
748   case bitc::ATTR_KIND_NON_LAZY_BIND:
749     return Attribute::NonLazyBind;
750   case bitc::ATTR_KIND_NON_NULL:
751     return Attribute::NonNull;
752   case bitc::ATTR_KIND_DEREFERENCEABLE:
753     return Attribute::Dereferenceable;
754   case bitc::ATTR_KIND_NO_RED_ZONE:
755     return Attribute::NoRedZone;
756   case bitc::ATTR_KIND_NO_RETURN:
757     return Attribute::NoReturn;
758   case bitc::ATTR_KIND_NO_UNWIND:
759     return Attribute::NoUnwind;
760   case bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE:
761     return Attribute::OptimizeForSize;
762   case bitc::ATTR_KIND_OPTIMIZE_NONE:
763     return Attribute::OptimizeNone;
764   case bitc::ATTR_KIND_READ_NONE:
765     return Attribute::ReadNone;
766   case bitc::ATTR_KIND_READ_ONLY:
767     return Attribute::ReadOnly;
768   case bitc::ATTR_KIND_RETURNED:
769     return Attribute::Returned;
770   case bitc::ATTR_KIND_RETURNS_TWICE:
771     return Attribute::ReturnsTwice;
772   case bitc::ATTR_KIND_S_EXT:
773     return Attribute::SExt;
774   case bitc::ATTR_KIND_STACK_ALIGNMENT:
775     return Attribute::StackAlignment;
776   case bitc::ATTR_KIND_STACK_PROTECT:
777     return Attribute::StackProtect;
778   case bitc::ATTR_KIND_STACK_PROTECT_REQ:
779     return Attribute::StackProtectReq;
780   case bitc::ATTR_KIND_STACK_PROTECT_STRONG:
781     return Attribute::StackProtectStrong;
782   case bitc::ATTR_KIND_STRUCT_RET:
783     return Attribute::StructRet;
784   case bitc::ATTR_KIND_SANITIZE_ADDRESS:
785     return Attribute::SanitizeAddress;
786   case bitc::ATTR_KIND_SANITIZE_THREAD:
787     return Attribute::SanitizeThread;
788   case bitc::ATTR_KIND_SANITIZE_MEMORY:
789     return Attribute::SanitizeMemory;
790   case bitc::ATTR_KIND_UW_TABLE:
791     return Attribute::UWTable;
792   case bitc::ATTR_KIND_Z_EXT:
793     return Attribute::ZExt;
794   }
795 }
796 
797 std::error_code BitcodeReader::ParseAttrKind(uint64_t Code,
798                                              Attribute::AttrKind *Kind) {
799   *Kind = GetAttrFromCode(Code);
800   if (*Kind == Attribute::None)
801     return Error(BitcodeError::CorruptedBitcode,
802                  "Unknown attribute kind (" + Twine(Code) + ")");
803   return std::error_code();
804 }
805 
806 std::error_code BitcodeReader::ParseAttributeGroupBlock() {
807   if (Stream.EnterSubBlock(bitc::PARAMATTR_GROUP_BLOCK_ID))
808     return Error("Invalid record");
809 
810   if (!MAttributeGroups.empty())
811     return Error("Invalid multiple blocks");
812 
813   SmallVector<uint64_t, 64> Record;
814 
815   // Read all the records.
816   while (1) {
817     BitstreamEntry Entry = Stream.advanceSkippingSubblocks();
818 
819     switch (Entry.Kind) {
820     case BitstreamEntry::SubBlock: // Handled for us already.
821     case BitstreamEntry::Error:
822       return Error("Malformed block");
823     case BitstreamEntry::EndBlock:
824       return std::error_code();
825     case BitstreamEntry::Record:
826       // The interesting case.
827       break;
828     }
829 
830     // Read a record.
831     Record.clear();
832     switch (Stream.readRecord(Entry.ID, Record)) {
833     default:  // Default behavior: ignore.
834       break;
835     case bitc::PARAMATTR_GRP_CODE_ENTRY: { // ENTRY: [grpid, idx, a0, a1, ...]
836       if (Record.size() < 3)
837         return Error("Invalid record");
838 
839       uint64_t GrpID = Record[0];
840       uint64_t Idx = Record[1]; // Index of the object this attribute refers to.
841 
842       AttrBuilder B;
843       for (unsigned i = 2, e = Record.size(); i != e; ++i) {
844         if (Record[i] == 0) {        // Enum attribute
845           Attribute::AttrKind Kind;
846           if (std::error_code EC = ParseAttrKind(Record[++i], &Kind))
847             return EC;
848 
849           B.addAttribute(Kind);
850         } else if (Record[i] == 1) { // Integer attribute
851           Attribute::AttrKind Kind;
852           if (std::error_code EC = ParseAttrKind(Record[++i], &Kind))
853             return EC;
854           if (Kind == Attribute::Alignment)
855             B.addAlignmentAttr(Record[++i]);
856           else if (Kind == Attribute::StackAlignment)
857             B.addStackAlignmentAttr(Record[++i]);
858           else if (Kind == Attribute::Dereferenceable)
859             B.addDereferenceableAttr(Record[++i]);
860         } else {                     // String attribute
861           assert((Record[i] == 3 || Record[i] == 4) &&
862                  "Invalid attribute group entry");
863           bool HasValue = (Record[i++] == 4);
864           SmallString<64> KindStr;
865           SmallString<64> ValStr;
866 
867           while (Record[i] != 0 && i != e)
868             KindStr += Record[i++];
869           assert(Record[i] == 0 && "Kind string not null terminated");
870 
871           if (HasValue) {
872             // Has a value associated with it.
873             ++i; // Skip the '0' that terminates the "kind" string.
874             while (Record[i] != 0 && i != e)
875               ValStr += Record[i++];
876             assert(Record[i] == 0 && "Value string not null terminated");
877           }
878 
879           B.addAttribute(KindStr.str(), ValStr.str());
880         }
881       }
882 
883       MAttributeGroups[GrpID] = AttributeSet::get(Context, Idx, B);
884       break;
885     }
886     }
887   }
888 }
889 
890 std::error_code BitcodeReader::ParseTypeTable() {
891   if (Stream.EnterSubBlock(bitc::TYPE_BLOCK_ID_NEW))
892     return Error("Invalid record");
893 
894   return ParseTypeTableBody();
895 }
896 
897 std::error_code BitcodeReader::ParseTypeTableBody() {
898   if (!TypeList.empty())
899     return Error("Invalid multiple blocks");
900 
901   SmallVector<uint64_t, 64> Record;
902   unsigned NumRecords = 0;
903 
904   SmallString<64> TypeName;
905 
906   // Read all the records for this type table.
907   while (1) {
908     BitstreamEntry Entry = Stream.advanceSkippingSubblocks();
909 
910     switch (Entry.Kind) {
911     case BitstreamEntry::SubBlock: // Handled for us already.
912     case BitstreamEntry::Error:
913       return Error("Malformed block");
914     case BitstreamEntry::EndBlock:
915       if (NumRecords != TypeList.size())
916         return Error("Malformed block");
917       return std::error_code();
918     case BitstreamEntry::Record:
919       // The interesting case.
920       break;
921     }
922 
923     // Read a record.
924     Record.clear();
925     Type *ResultTy = nullptr;
926     switch (Stream.readRecord(Entry.ID, Record)) {
927     default:
928       return Error("Invalid value");
929     case bitc::TYPE_CODE_NUMENTRY: // TYPE_CODE_NUMENTRY: [numentries]
930       // TYPE_CODE_NUMENTRY contains a count of the number of types in the
931       // type list.  This allows us to reserve space.
932       if (Record.size() < 1)
933         return Error("Invalid record");
934       TypeList.resize(Record[0]);
935       continue;
936     case bitc::TYPE_CODE_VOID:      // VOID
937       ResultTy = Type::getVoidTy(Context);
938       break;
939     case bitc::TYPE_CODE_HALF:     // HALF
940       ResultTy = Type::getHalfTy(Context);
941       break;
942     case bitc::TYPE_CODE_FLOAT:     // FLOAT
943       ResultTy = Type::getFloatTy(Context);
944       break;
945     case bitc::TYPE_CODE_DOUBLE:    // DOUBLE
946       ResultTy = Type::getDoubleTy(Context);
947       break;
948     case bitc::TYPE_CODE_X86_FP80:  // X86_FP80
949       ResultTy = Type::getX86_FP80Ty(Context);
950       break;
951     case bitc::TYPE_CODE_FP128:     // FP128
952       ResultTy = Type::getFP128Ty(Context);
953       break;
954     case bitc::TYPE_CODE_PPC_FP128: // PPC_FP128
955       ResultTy = Type::getPPC_FP128Ty(Context);
956       break;
957     case bitc::TYPE_CODE_LABEL:     // LABEL
958       ResultTy = Type::getLabelTy(Context);
959       break;
960     case bitc::TYPE_CODE_METADATA:  // METADATA
961       ResultTy = Type::getMetadataTy(Context);
962       break;
963     case bitc::TYPE_CODE_X86_MMX:   // X86_MMX
964       ResultTy = Type::getX86_MMXTy(Context);
965       break;
966     case bitc::TYPE_CODE_INTEGER: { // INTEGER: [width]
967       if (Record.size() < 1)
968         return Error("Invalid record");
969 
970       uint64_t NumBits = Record[0];
971       if (NumBits < IntegerType::MIN_INT_BITS ||
972           NumBits > IntegerType::MAX_INT_BITS)
973         return Error("Bitwidth for integer type out of range");
974       ResultTy = IntegerType::get(Context, NumBits);
975       break;
976     }
977     case bitc::TYPE_CODE_POINTER: { // POINTER: [pointee type] or
978                                     //          [pointee type, address space]
979       if (Record.size() < 1)
980         return Error("Invalid record");
981       unsigned AddressSpace = 0;
982       if (Record.size() == 2)
983         AddressSpace = Record[1];
984       ResultTy = getTypeByID(Record[0]);
985       if (!ResultTy)
986         return Error("Invalid type");
987       ResultTy = PointerType::get(ResultTy, AddressSpace);
988       break;
989     }
990     case bitc::TYPE_CODE_FUNCTION_OLD: {
991       // FIXME: attrid is dead, remove it in LLVM 4.0
992       // FUNCTION: [vararg, attrid, retty, paramty x N]
993       if (Record.size() < 3)
994         return Error("Invalid record");
995       SmallVector<Type*, 8> ArgTys;
996       for (unsigned i = 3, e = Record.size(); i != e; ++i) {
997         if (Type *T = getTypeByID(Record[i]))
998           ArgTys.push_back(T);
999         else
1000           break;
1001       }
1002 
1003       ResultTy = getTypeByID(Record[2]);
1004       if (!ResultTy || ArgTys.size() < Record.size()-3)
1005         return Error("Invalid type");
1006 
1007       ResultTy = FunctionType::get(ResultTy, ArgTys, Record[0]);
1008       break;
1009     }
1010     case bitc::TYPE_CODE_FUNCTION: {
1011       // FUNCTION: [vararg, retty, paramty x N]
1012       if (Record.size() < 2)
1013         return Error("Invalid record");
1014       SmallVector<Type*, 8> ArgTys;
1015       for (unsigned i = 2, e = Record.size(); i != e; ++i) {
1016         if (Type *T = getTypeByID(Record[i]))
1017           ArgTys.push_back(T);
1018         else
1019           break;
1020       }
1021 
1022       ResultTy = getTypeByID(Record[1]);
1023       if (!ResultTy || ArgTys.size() < Record.size()-2)
1024         return Error("Invalid type");
1025 
1026       ResultTy = FunctionType::get(ResultTy, ArgTys, Record[0]);
1027       break;
1028     }
1029     case bitc::TYPE_CODE_STRUCT_ANON: {  // STRUCT: [ispacked, eltty x N]
1030       if (Record.size() < 1)
1031         return Error("Invalid record");
1032       SmallVector<Type*, 8> EltTys;
1033       for (unsigned i = 1, e = Record.size(); i != e; ++i) {
1034         if (Type *T = getTypeByID(Record[i]))
1035           EltTys.push_back(T);
1036         else
1037           break;
1038       }
1039       if (EltTys.size() != Record.size()-1)
1040         return Error("Invalid type");
1041       ResultTy = StructType::get(Context, EltTys, Record[0]);
1042       break;
1043     }
1044     case bitc::TYPE_CODE_STRUCT_NAME:   // STRUCT_NAME: [strchr x N]
1045       if (ConvertToString(Record, 0, TypeName))
1046         return Error("Invalid record");
1047       continue;
1048 
1049     case bitc::TYPE_CODE_STRUCT_NAMED: { // STRUCT: [ispacked, eltty x N]
1050       if (Record.size() < 1)
1051         return Error("Invalid record");
1052 
1053       if (NumRecords >= TypeList.size())
1054         return Error("Invalid TYPE table");
1055 
1056       // Check to see if this was forward referenced, if so fill in the temp.
1057       StructType *Res = cast_or_null<StructType>(TypeList[NumRecords]);
1058       if (Res) {
1059         Res->setName(TypeName);
1060         TypeList[NumRecords] = nullptr;
1061       } else  // Otherwise, create a new struct.
1062         Res = createIdentifiedStructType(Context, TypeName);
1063       TypeName.clear();
1064 
1065       SmallVector<Type*, 8> EltTys;
1066       for (unsigned i = 1, e = Record.size(); i != e; ++i) {
1067         if (Type *T = getTypeByID(Record[i]))
1068           EltTys.push_back(T);
1069         else
1070           break;
1071       }
1072       if (EltTys.size() != Record.size()-1)
1073         return Error("Invalid record");
1074       Res->setBody(EltTys, Record[0]);
1075       ResultTy = Res;
1076       break;
1077     }
1078     case bitc::TYPE_CODE_OPAQUE: {       // OPAQUE: []
1079       if (Record.size() != 1)
1080         return Error("Invalid record");
1081 
1082       if (NumRecords >= TypeList.size())
1083         return Error("Invalid TYPE table");
1084 
1085       // Check to see if this was forward referenced, if so fill in the temp.
1086       StructType *Res = cast_or_null<StructType>(TypeList[NumRecords]);
1087       if (Res) {
1088         Res->setName(TypeName);
1089         TypeList[NumRecords] = nullptr;
1090       } else  // Otherwise, create a new struct with no body.
1091         Res = createIdentifiedStructType(Context, TypeName);
1092       TypeName.clear();
1093       ResultTy = Res;
1094       break;
1095     }
1096     case bitc::TYPE_CODE_ARRAY:     // ARRAY: [numelts, eltty]
1097       if (Record.size() < 2)
1098         return Error("Invalid record");
1099       if ((ResultTy = getTypeByID(Record[1])))
1100         ResultTy = ArrayType::get(ResultTy, Record[0]);
1101       else
1102         return Error("Invalid type");
1103       break;
1104     case bitc::TYPE_CODE_VECTOR:    // VECTOR: [numelts, eltty]
1105       if (Record.size() < 2)
1106         return Error("Invalid record");
1107       if ((ResultTy = getTypeByID(Record[1])))
1108         ResultTy = VectorType::get(ResultTy, Record[0]);
1109       else
1110         return Error("Invalid type");
1111       break;
1112     }
1113 
1114     if (NumRecords >= TypeList.size())
1115       return Error("Invalid TYPE table");
1116     if (TypeList[NumRecords])
1117       return Error(
1118           "Invalid TYPE table: Only named structs can be forward referenced");
1119     assert(ResultTy && "Didn't read a type?");
1120     TypeList[NumRecords++] = ResultTy;
1121   }
1122 }
1123 
1124 std::error_code BitcodeReader::ParseValueSymbolTable() {
1125   if (Stream.EnterSubBlock(bitc::VALUE_SYMTAB_BLOCK_ID))
1126     return Error("Invalid record");
1127 
1128   SmallVector<uint64_t, 64> Record;
1129 
1130   Triple TT(TheModule->getTargetTriple());
1131 
1132   // Read all the records for this value table.
1133   SmallString<128> ValueName;
1134   while (1) {
1135     BitstreamEntry Entry = Stream.advanceSkippingSubblocks();
1136 
1137     switch (Entry.Kind) {
1138     case BitstreamEntry::SubBlock: // Handled for us already.
1139     case BitstreamEntry::Error:
1140       return Error("Malformed block");
1141     case BitstreamEntry::EndBlock:
1142       return std::error_code();
1143     case BitstreamEntry::Record:
1144       // The interesting case.
1145       break;
1146     }
1147 
1148     // Read a record.
1149     Record.clear();
1150     switch (Stream.readRecord(Entry.ID, Record)) {
1151     default:  // Default behavior: unknown type.
1152       break;
1153     case bitc::VST_CODE_ENTRY: {  // VST_ENTRY: [valueid, namechar x N]
1154       if (ConvertToString(Record, 1, ValueName))
1155         return Error("Invalid record");
1156       unsigned ValueID = Record[0];
1157       if (ValueID >= ValueList.size() || !ValueList[ValueID])
1158         return Error("Invalid record");
1159       Value *V = ValueList[ValueID];
1160 
1161       V->setName(StringRef(ValueName.data(), ValueName.size()));
1162       if (auto *GO = dyn_cast<GlobalObject>(V)) {
1163         if (GO->getComdat() == reinterpret_cast<Comdat *>(1)) {
1164           if (TT.isOSBinFormatMachO())
1165             GO->setComdat(nullptr);
1166           else
1167             GO->setComdat(TheModule->getOrInsertComdat(V->getName()));
1168         }
1169       }
1170       ValueName.clear();
1171       break;
1172     }
1173     case bitc::VST_CODE_BBENTRY: {
1174       if (ConvertToString(Record, 1, ValueName))
1175         return Error("Invalid record");
1176       BasicBlock *BB = getBasicBlock(Record[0]);
1177       if (!BB)
1178         return Error("Invalid record");
1179 
1180       BB->setName(StringRef(ValueName.data(), ValueName.size()));
1181       ValueName.clear();
1182       break;
1183     }
1184     }
1185   }
1186 }
1187 
1188 static int64_t unrotateSign(uint64_t U) { return U & 1 ? ~(U >> 1) : U >> 1; }
1189 
1190 std::error_code BitcodeReader::ParseMetadata() {
1191   unsigned NextMDValueNo = MDValueList.size();
1192 
1193   if (Stream.EnterSubBlock(bitc::METADATA_BLOCK_ID))
1194     return Error("Invalid record");
1195 
1196   SmallVector<uint64_t, 64> Record;
1197 
1198   auto getMD =
1199       [&](unsigned ID) -> Metadata *{ return MDValueList.getValueFwdRef(ID); };
1200   auto getMDOrNull = [&](unsigned ID) -> Metadata *{
1201     if (ID)
1202       return getMD(ID - 1);
1203     return nullptr;
1204   };
1205   auto getMDString = [&](unsigned ID) -> MDString *{
1206     // This requires that the ID is not really a forward reference.  In
1207     // particular, the MDString must already have been resolved.
1208     return cast_or_null<MDString>(getMDOrNull(ID));
1209   };
1210 
1211 #define GET_OR_DISTINCT(CLASS, DISTINCT, ARGS)                                 \
1212   (DISTINCT ? CLASS::getDistinct ARGS : CLASS::get ARGS)
1213 
1214   // Read all the records.
1215   while (1) {
1216     BitstreamEntry Entry = Stream.advanceSkippingSubblocks();
1217 
1218     switch (Entry.Kind) {
1219     case BitstreamEntry::SubBlock: // Handled for us already.
1220     case BitstreamEntry::Error:
1221       return Error("Malformed block");
1222     case BitstreamEntry::EndBlock:
1223       MDValueList.tryToResolveCycles();
1224       return std::error_code();
1225     case BitstreamEntry::Record:
1226       // The interesting case.
1227       break;
1228     }
1229 
1230     // Read a record.
1231     Record.clear();
1232     unsigned Code = Stream.readRecord(Entry.ID, Record);
1233     bool IsDistinct = false;
1234     switch (Code) {
1235     default:  // Default behavior: ignore.
1236       break;
1237     case bitc::METADATA_NAME: {
1238       // Read name of the named metadata.
1239       SmallString<8> Name(Record.begin(), Record.end());
1240       Record.clear();
1241       Code = Stream.ReadCode();
1242 
1243       // METADATA_NAME is always followed by METADATA_NAMED_NODE.
1244       unsigned NextBitCode = Stream.readRecord(Code, Record);
1245       assert(NextBitCode == bitc::METADATA_NAMED_NODE); (void)NextBitCode;
1246 
1247       // Read named metadata elements.
1248       unsigned Size = Record.size();
1249       NamedMDNode *NMD = TheModule->getOrInsertNamedMetadata(Name);
1250       for (unsigned i = 0; i != Size; ++i) {
1251         MDNode *MD = dyn_cast_or_null<MDNode>(MDValueList.getValueFwdRef(Record[i]));
1252         if (!MD)
1253           return Error("Invalid record");
1254         NMD->addOperand(MD);
1255       }
1256       break;
1257     }
1258     case bitc::METADATA_OLD_FN_NODE: {
1259       // FIXME: Remove in 4.0.
1260       // This is a LocalAsMetadata record, the only type of function-local
1261       // metadata.
1262       if (Record.size() % 2 == 1)
1263         return Error("Invalid record");
1264 
1265       // If this isn't a LocalAsMetadata record, we're dropping it.  This used
1266       // to be legal, but there's no upgrade path.
1267       auto dropRecord = [&] {
1268         MDValueList.AssignValue(MDNode::get(Context, None), NextMDValueNo++);
1269       };
1270       if (Record.size() != 2) {
1271         dropRecord();
1272         break;
1273       }
1274 
1275       Type *Ty = getTypeByID(Record[0]);
1276       if (Ty->isMetadataTy() || Ty->isVoidTy()) {
1277         dropRecord();
1278         break;
1279       }
1280 
1281       MDValueList.AssignValue(
1282           LocalAsMetadata::get(ValueList.getValueFwdRef(Record[1], Ty)),
1283           NextMDValueNo++);
1284       break;
1285     }
1286     case bitc::METADATA_OLD_NODE: {
1287       // FIXME: Remove in 4.0.
1288       if (Record.size() % 2 == 1)
1289         return Error("Invalid record");
1290 
1291       unsigned Size = Record.size();
1292       SmallVector<Metadata *, 8> Elts;
1293       for (unsigned i = 0; i != Size; i += 2) {
1294         Type *Ty = getTypeByID(Record[i]);
1295         if (!Ty)
1296           return Error("Invalid record");
1297         if (Ty->isMetadataTy())
1298           Elts.push_back(MDValueList.getValueFwdRef(Record[i+1]));
1299         else if (!Ty->isVoidTy()) {
1300           auto *MD =
1301               ValueAsMetadata::get(ValueList.getValueFwdRef(Record[i + 1], Ty));
1302           assert(isa<ConstantAsMetadata>(MD) &&
1303                  "Expected non-function-local metadata");
1304           Elts.push_back(MD);
1305         } else
1306           Elts.push_back(nullptr);
1307       }
1308       MDValueList.AssignValue(MDNode::get(Context, Elts), NextMDValueNo++);
1309       break;
1310     }
1311     case bitc::METADATA_VALUE: {
1312       if (Record.size() != 2)
1313         return Error("Invalid record");
1314 
1315       Type *Ty = getTypeByID(Record[0]);
1316       if (Ty->isMetadataTy() || Ty->isVoidTy())
1317         return Error("Invalid record");
1318 
1319       MDValueList.AssignValue(
1320           ValueAsMetadata::get(ValueList.getValueFwdRef(Record[1], Ty)),
1321           NextMDValueNo++);
1322       break;
1323     }
1324     case bitc::METADATA_DISTINCT_NODE:
1325       IsDistinct = true;
1326       // fallthrough...
1327     case bitc::METADATA_NODE: {
1328       SmallVector<Metadata *, 8> Elts;
1329       Elts.reserve(Record.size());
1330       for (unsigned ID : Record)
1331         Elts.push_back(ID ? MDValueList.getValueFwdRef(ID - 1) : nullptr);
1332       MDValueList.AssignValue(IsDistinct ? MDNode::getDistinct(Context, Elts)
1333                                          : MDNode::get(Context, Elts),
1334                               NextMDValueNo++);
1335       break;
1336     }
1337     case bitc::METADATA_LOCATION: {
1338       if (Record.size() != 5)
1339         return Error("Invalid record");
1340 
1341       auto get = Record[0] ? MDLocation::getDistinct : MDLocation::get;
1342       unsigned Line = Record[1];
1343       unsigned Column = Record[2];
1344       MDNode *Scope = cast<MDNode>(MDValueList.getValueFwdRef(Record[3]));
1345       Metadata *InlinedAt =
1346           Record[4] ? MDValueList.getValueFwdRef(Record[4] - 1) : nullptr;
1347       MDValueList.AssignValue(get(Context, Line, Column, Scope, InlinedAt),
1348                               NextMDValueNo++);
1349       break;
1350     }
1351     case bitc::METADATA_GENERIC_DEBUG: {
1352       if (Record.size() < 4)
1353         return Error("Invalid record");
1354 
1355       unsigned Tag = Record[1];
1356       unsigned Version = Record[2];
1357 
1358       if (Tag >= 1u << 16 || Version != 0)
1359         return Error("Invalid record");
1360 
1361       auto *Header = getMDString(Record[3]);
1362       SmallVector<Metadata *, 8> DwarfOps;
1363       for (unsigned I = 4, E = Record.size(); I != E; ++I)
1364         DwarfOps.push_back(Record[I] ? MDValueList.getValueFwdRef(Record[I] - 1)
1365                                      : nullptr);
1366       MDValueList.AssignValue(GET_OR_DISTINCT(GenericDebugNode, Record[0],
1367                                               (Context, Tag, Header, DwarfOps)),
1368                               NextMDValueNo++);
1369       break;
1370     }
1371     case bitc::METADATA_SUBRANGE: {
1372       if (Record.size() != 3)
1373         return Error("Invalid record");
1374 
1375       MDValueList.AssignValue(
1376           GET_OR_DISTINCT(MDSubrange, Record[0],
1377                           (Context, Record[1], unrotateSign(Record[2]))),
1378           NextMDValueNo++);
1379       break;
1380     }
1381     case bitc::METADATA_ENUMERATOR: {
1382       if (Record.size() != 3)
1383         return Error("Invalid record");
1384 
1385       MDValueList.AssignValue(GET_OR_DISTINCT(MDEnumerator, Record[0],
1386                                               (Context, unrotateSign(Record[1]),
1387                                                getMDString(Record[2]))),
1388                               NextMDValueNo++);
1389       break;
1390     }
1391     case bitc::METADATA_BASIC_TYPE: {
1392       if (Record.size() != 6)
1393         return Error("Invalid record");
1394 
1395       MDValueList.AssignValue(
1396           GET_OR_DISTINCT(MDBasicType, Record[0],
1397                           (Context, Record[1], getMDString(Record[2]),
1398                            Record[3], Record[4], Record[5])),
1399           NextMDValueNo++);
1400       break;
1401     }
1402     case bitc::METADATA_DERIVED_TYPE: {
1403       if (Record.size() != 12)
1404         return Error("Invalid record");
1405 
1406       MDValueList.AssignValue(
1407           GET_OR_DISTINCT(MDDerivedType, Record[0],
1408                           (Context, Record[1], getMDString(Record[2]),
1409                            getMDOrNull(Record[3]), Record[4],
1410                            getMDOrNull(Record[5]), getMD(Record[6]), Record[7],
1411                            Record[8], Record[9], Record[10],
1412                            getMDOrNull(Record[11]))),
1413           NextMDValueNo++);
1414       break;
1415     }
1416     case bitc::METADATA_COMPOSITE_TYPE: {
1417       if (Record.size() != 16)
1418         return Error("Invalid record");
1419 
1420       MDValueList.AssignValue(
1421           GET_OR_DISTINCT(MDCompositeType, Record[0],
1422                           (Context, Record[1], getMDString(Record[2]),
1423                            getMDOrNull(Record[3]), Record[4],
1424                            getMDOrNull(Record[5]), getMDOrNull(Record[6]),
1425                            Record[7], Record[8], Record[9], Record[10],
1426                            getMDOrNull(Record[11]), Record[12],
1427                            getMDOrNull(Record[13]), getMDOrNull(Record[14]),
1428                            getMDString(Record[15]))),
1429           NextMDValueNo++);
1430       break;
1431     }
1432     case bitc::METADATA_SUBROUTINE_TYPE: {
1433       if (Record.size() != 3)
1434         return Error("Invalid record");
1435 
1436       MDValueList.AssignValue(
1437           GET_OR_DISTINCT(MDSubroutineType, Record[0],
1438                           (Context, Record[1], getMDOrNull(Record[2]))),
1439           NextMDValueNo++);
1440       break;
1441     }
1442     case bitc::METADATA_FILE: {
1443       if (Record.size() != 3)
1444         return Error("Invalid record");
1445 
1446       MDValueList.AssignValue(
1447           GET_OR_DISTINCT(MDFile, Record[0], (Context, getMDString(Record[1]),
1448                                               getMDString(Record[2]))),
1449           NextMDValueNo++);
1450       break;
1451     }
1452     case bitc::METADATA_COMPILE_UNIT: {
1453       if (Record.size() != 14)
1454         return Error("Invalid record");
1455 
1456       MDValueList.AssignValue(
1457           GET_OR_DISTINCT(
1458               MDCompileUnit, Record[0],
1459               (Context, Record[1], getMD(Record[2]), getMDString(Record[3]),
1460                Record[4], getMDString(Record[5]), Record[6],
1461                getMDString(Record[7]), Record[8], getMDOrNull(Record[9]),
1462                getMDOrNull(Record[10]), getMDOrNull(Record[11]),
1463                getMDOrNull(Record[12]), getMDOrNull(Record[13]))),
1464           NextMDValueNo++);
1465       break;
1466     }
1467     case bitc::METADATA_SUBPROGRAM: {
1468       if (Record.size() != 19)
1469         return Error("Invalid record");
1470 
1471       MDValueList.AssignValue(
1472           GET_OR_DISTINCT(
1473               MDSubprogram, Record[0],
1474               (Context, getMDOrNull(Record[1]), getMDString(Record[2]),
1475                getMDString(Record[3]), getMDOrNull(Record[4]), Record[5],
1476                getMDOrNull(Record[6]), Record[7], Record[8], Record[9],
1477                getMDOrNull(Record[10]), Record[11], Record[12], Record[13],
1478                Record[14], getMDOrNull(Record[15]), getMDOrNull(Record[16]),
1479                getMDOrNull(Record[17]), getMDOrNull(Record[18]))),
1480           NextMDValueNo++);
1481       break;
1482     }
1483     case bitc::METADATA_LEXICAL_BLOCK: {
1484       if (Record.size() != 5)
1485         return Error("Invalid record");
1486 
1487       MDValueList.AssignValue(
1488           GET_OR_DISTINCT(MDLexicalBlock, Record[0],
1489                           (Context, getMDOrNull(Record[1]),
1490                            getMDOrNull(Record[2]), Record[3], Record[4])),
1491           NextMDValueNo++);
1492       break;
1493     }
1494     case bitc::METADATA_LEXICAL_BLOCK_FILE: {
1495       if (Record.size() != 4)
1496         return Error("Invalid record");
1497 
1498       MDValueList.AssignValue(
1499           GET_OR_DISTINCT(MDLexicalBlockFile, Record[0],
1500                           (Context, getMDOrNull(Record[1]),
1501                            getMDOrNull(Record[2]), Record[3])),
1502           NextMDValueNo++);
1503       break;
1504     }
1505     case bitc::METADATA_NAMESPACE: {
1506       if (Record.size() != 5)
1507         return Error("Invalid record");
1508 
1509       MDValueList.AssignValue(
1510           GET_OR_DISTINCT(MDNamespace, Record[0],
1511                           (Context, getMDOrNull(Record[1]),
1512                            getMDOrNull(Record[2]), getMDString(Record[3]),
1513                            Record[4])),
1514           NextMDValueNo++);
1515       break;
1516     }
1517     case bitc::METADATA_TEMPLATE_TYPE: {
1518       if (Record.size() != 3)
1519         return Error("Invalid record");
1520 
1521       MDValueList.AssignValue(GET_OR_DISTINCT(MDTemplateTypeParameter,
1522                                               Record[0],
1523                                               (Context, getMDString(Record[1]),
1524                                                getMDOrNull(Record[2]))),
1525                               NextMDValueNo++);
1526       break;
1527     }
1528     case bitc::METADATA_TEMPLATE_VALUE: {
1529       if (Record.size() != 5)
1530         return Error("Invalid record");
1531 
1532       MDValueList.AssignValue(
1533           GET_OR_DISTINCT(MDTemplateValueParameter, Record[0],
1534                           (Context, Record[1], getMDString(Record[2]),
1535                            getMDOrNull(Record[3]), getMDOrNull(Record[4]))),
1536           NextMDValueNo++);
1537       break;
1538     }
1539     case bitc::METADATA_GLOBAL_VAR: {
1540       if (Record.size() != 11)
1541         return Error("Invalid record");
1542 
1543       MDValueList.AssignValue(
1544           GET_OR_DISTINCT(MDGlobalVariable, Record[0],
1545                           (Context, getMDOrNull(Record[1]),
1546                            getMDString(Record[2]), getMDString(Record[3]),
1547                            getMDOrNull(Record[4]), Record[5],
1548                            getMDOrNull(Record[6]), Record[7], Record[8],
1549                            getMDOrNull(Record[9]), getMDOrNull(Record[10]))),
1550           NextMDValueNo++);
1551       break;
1552     }
1553     case bitc::METADATA_LOCAL_VAR: {
1554       if (Record.size() != 10)
1555         return Error("Invalid record");
1556 
1557       MDValueList.AssignValue(
1558           GET_OR_DISTINCT(MDLocalVariable, Record[0],
1559                           (Context, Record[1], getMDOrNull(Record[2]),
1560                            getMDString(Record[3]), getMDOrNull(Record[4]),
1561                            Record[5], getMDOrNull(Record[6]), Record[7],
1562                            Record[8], getMDOrNull(Record[9]))),
1563           NextMDValueNo++);
1564       break;
1565     }
1566     case bitc::METADATA_EXPRESSION: {
1567       if (Record.size() < 1)
1568         return Error("Invalid record");
1569 
1570       MDValueList.AssignValue(
1571           GET_OR_DISTINCT(MDExpression, Record[0],
1572                           (Context, makeArrayRef(Record).slice(1))),
1573           NextMDValueNo++);
1574       break;
1575     }
1576     case bitc::METADATA_OBJC_PROPERTY: {
1577       if (Record.size() != 8)
1578         return Error("Invalid record");
1579 
1580       MDValueList.AssignValue(
1581           GET_OR_DISTINCT(MDObjCProperty, Record[0],
1582                           (Context, getMDString(Record[1]),
1583                            getMDOrNull(Record[2]), Record[3],
1584                            getMDString(Record[4]), getMDString(Record[5]),
1585                            Record[6], getMDOrNull(Record[7]))),
1586           NextMDValueNo++);
1587       break;
1588     }
1589     case bitc::METADATA_IMPORTED_ENTITY: {
1590       if (Record.size() != 6)
1591         return Error("Invalid record");
1592 
1593       MDValueList.AssignValue(
1594           GET_OR_DISTINCT(MDImportedEntity, Record[0],
1595                           (Context, Record[1], getMDOrNull(Record[2]),
1596                            getMDOrNull(Record[3]), Record[4],
1597                            getMDString(Record[5]))),
1598           NextMDValueNo++);
1599       break;
1600     }
1601     case bitc::METADATA_STRING: {
1602       std::string String(Record.begin(), Record.end());
1603       llvm::UpgradeMDStringConstant(String);
1604       Metadata *MD = MDString::get(Context, String);
1605       MDValueList.AssignValue(MD, NextMDValueNo++);
1606       break;
1607     }
1608     case bitc::METADATA_KIND: {
1609       if (Record.size() < 2)
1610         return Error("Invalid record");
1611 
1612       unsigned Kind = Record[0];
1613       SmallString<8> Name(Record.begin()+1, Record.end());
1614 
1615       unsigned NewKind = TheModule->getMDKindID(Name.str());
1616       if (!MDKindMap.insert(std::make_pair(Kind, NewKind)).second)
1617         return Error("Conflicting METADATA_KIND records");
1618       break;
1619     }
1620     }
1621   }
1622 #undef GET_OR_DISTINCT
1623 }
1624 
1625 /// decodeSignRotatedValue - Decode a signed value stored with the sign bit in
1626 /// the LSB for dense VBR encoding.
1627 uint64_t BitcodeReader::decodeSignRotatedValue(uint64_t V) {
1628   if ((V & 1) == 0)
1629     return V >> 1;
1630   if (V != 1)
1631     return -(V >> 1);
1632   // There is no such thing as -0 with integers.  "-0" really means MININT.
1633   return 1ULL << 63;
1634 }
1635 
1636 /// ResolveGlobalAndAliasInits - Resolve all of the initializers for global
1637 /// values and aliases that we can.
1638 std::error_code BitcodeReader::ResolveGlobalAndAliasInits() {
1639   std::vector<std::pair<GlobalVariable*, unsigned> > GlobalInitWorklist;
1640   std::vector<std::pair<GlobalAlias*, unsigned> > AliasInitWorklist;
1641   std::vector<std::pair<Function*, unsigned> > FunctionPrefixWorklist;
1642   std::vector<std::pair<Function*, unsigned> > FunctionPrologueWorklist;
1643 
1644   GlobalInitWorklist.swap(GlobalInits);
1645   AliasInitWorklist.swap(AliasInits);
1646   FunctionPrefixWorklist.swap(FunctionPrefixes);
1647   FunctionPrologueWorklist.swap(FunctionPrologues);
1648 
1649   while (!GlobalInitWorklist.empty()) {
1650     unsigned ValID = GlobalInitWorklist.back().second;
1651     if (ValID >= ValueList.size()) {
1652       // Not ready to resolve this yet, it requires something later in the file.
1653       GlobalInits.push_back(GlobalInitWorklist.back());
1654     } else {
1655       if (Constant *C = dyn_cast_or_null<Constant>(ValueList[ValID]))
1656         GlobalInitWorklist.back().first->setInitializer(C);
1657       else
1658         return Error("Expected a constant");
1659     }
1660     GlobalInitWorklist.pop_back();
1661   }
1662 
1663   while (!AliasInitWorklist.empty()) {
1664     unsigned ValID = AliasInitWorklist.back().second;
1665     if (ValID >= ValueList.size()) {
1666       AliasInits.push_back(AliasInitWorklist.back());
1667     } else {
1668       if (Constant *C = dyn_cast_or_null<Constant>(ValueList[ValID]))
1669         AliasInitWorklist.back().first->setAliasee(C);
1670       else
1671         return Error("Expected a constant");
1672     }
1673     AliasInitWorklist.pop_back();
1674   }
1675 
1676   while (!FunctionPrefixWorklist.empty()) {
1677     unsigned ValID = FunctionPrefixWorklist.back().second;
1678     if (ValID >= ValueList.size()) {
1679       FunctionPrefixes.push_back(FunctionPrefixWorklist.back());
1680     } else {
1681       if (Constant *C = dyn_cast_or_null<Constant>(ValueList[ValID]))
1682         FunctionPrefixWorklist.back().first->setPrefixData(C);
1683       else
1684         return Error("Expected a constant");
1685     }
1686     FunctionPrefixWorklist.pop_back();
1687   }
1688 
1689   while (!FunctionPrologueWorklist.empty()) {
1690     unsigned ValID = FunctionPrologueWorklist.back().second;
1691     if (ValID >= ValueList.size()) {
1692       FunctionPrologues.push_back(FunctionPrologueWorklist.back());
1693     } else {
1694       if (Constant *C = dyn_cast_or_null<Constant>(ValueList[ValID]))
1695         FunctionPrologueWorklist.back().first->setPrologueData(C);
1696       else
1697         return Error("Expected a constant");
1698     }
1699     FunctionPrologueWorklist.pop_back();
1700   }
1701 
1702   return std::error_code();
1703 }
1704 
1705 static APInt ReadWideAPInt(ArrayRef<uint64_t> Vals, unsigned TypeBits) {
1706   SmallVector<uint64_t, 8> Words(Vals.size());
1707   std::transform(Vals.begin(), Vals.end(), Words.begin(),
1708                  BitcodeReader::decodeSignRotatedValue);
1709 
1710   return APInt(TypeBits, Words);
1711 }
1712 
1713 std::error_code BitcodeReader::ParseConstants() {
1714   if (Stream.EnterSubBlock(bitc::CONSTANTS_BLOCK_ID))
1715     return Error("Invalid record");
1716 
1717   SmallVector<uint64_t, 64> Record;
1718 
1719   // Read all the records for this value table.
1720   Type *CurTy = Type::getInt32Ty(Context);
1721   unsigned NextCstNo = ValueList.size();
1722   while (1) {
1723     BitstreamEntry Entry = Stream.advanceSkippingSubblocks();
1724 
1725     switch (Entry.Kind) {
1726     case BitstreamEntry::SubBlock: // Handled for us already.
1727     case BitstreamEntry::Error:
1728       return Error("Malformed block");
1729     case BitstreamEntry::EndBlock:
1730       if (NextCstNo != ValueList.size())
1731         return Error("Invalid ronstant reference");
1732 
1733       // Once all the constants have been read, go through and resolve forward
1734       // references.
1735       ValueList.ResolveConstantForwardRefs();
1736       return std::error_code();
1737     case BitstreamEntry::Record:
1738       // The interesting case.
1739       break;
1740     }
1741 
1742     // Read a record.
1743     Record.clear();
1744     Value *V = nullptr;
1745     unsigned BitCode = Stream.readRecord(Entry.ID, Record);
1746     switch (BitCode) {
1747     default:  // Default behavior: unknown constant
1748     case bitc::CST_CODE_UNDEF:     // UNDEF
1749       V = UndefValue::get(CurTy);
1750       break;
1751     case bitc::CST_CODE_SETTYPE:   // SETTYPE: [typeid]
1752       if (Record.empty())
1753         return Error("Invalid record");
1754       if (Record[0] >= TypeList.size() || !TypeList[Record[0]])
1755         return Error("Invalid record");
1756       CurTy = TypeList[Record[0]];
1757       continue;  // Skip the ValueList manipulation.
1758     case bitc::CST_CODE_NULL:      // NULL
1759       V = Constant::getNullValue(CurTy);
1760       break;
1761     case bitc::CST_CODE_INTEGER:   // INTEGER: [intval]
1762       if (!CurTy->isIntegerTy() || Record.empty())
1763         return Error("Invalid record");
1764       V = ConstantInt::get(CurTy, decodeSignRotatedValue(Record[0]));
1765       break;
1766     case bitc::CST_CODE_WIDE_INTEGER: {// WIDE_INTEGER: [n x intval]
1767       if (!CurTy->isIntegerTy() || Record.empty())
1768         return Error("Invalid record");
1769 
1770       APInt VInt = ReadWideAPInt(Record,
1771                                  cast<IntegerType>(CurTy)->getBitWidth());
1772       V = ConstantInt::get(Context, VInt);
1773 
1774       break;
1775     }
1776     case bitc::CST_CODE_FLOAT: {    // FLOAT: [fpval]
1777       if (Record.empty())
1778         return Error("Invalid record");
1779       if (CurTy->isHalfTy())
1780         V = ConstantFP::get(Context, APFloat(APFloat::IEEEhalf,
1781                                              APInt(16, (uint16_t)Record[0])));
1782       else if (CurTy->isFloatTy())
1783         V = ConstantFP::get(Context, APFloat(APFloat::IEEEsingle,
1784                                              APInt(32, (uint32_t)Record[0])));
1785       else if (CurTy->isDoubleTy())
1786         V = ConstantFP::get(Context, APFloat(APFloat::IEEEdouble,
1787                                              APInt(64, Record[0])));
1788       else if (CurTy->isX86_FP80Ty()) {
1789         // Bits are not stored the same way as a normal i80 APInt, compensate.
1790         uint64_t Rearrange[2];
1791         Rearrange[0] = (Record[1] & 0xffffLL) | (Record[0] << 16);
1792         Rearrange[1] = Record[0] >> 48;
1793         V = ConstantFP::get(Context, APFloat(APFloat::x87DoubleExtended,
1794                                              APInt(80, Rearrange)));
1795       } else if (CurTy->isFP128Ty())
1796         V = ConstantFP::get(Context, APFloat(APFloat::IEEEquad,
1797                                              APInt(128, Record)));
1798       else if (CurTy->isPPC_FP128Ty())
1799         V = ConstantFP::get(Context, APFloat(APFloat::PPCDoubleDouble,
1800                                              APInt(128, Record)));
1801       else
1802         V = UndefValue::get(CurTy);
1803       break;
1804     }
1805 
1806     case bitc::CST_CODE_AGGREGATE: {// AGGREGATE: [n x value number]
1807       if (Record.empty())
1808         return Error("Invalid record");
1809 
1810       unsigned Size = Record.size();
1811       SmallVector<Constant*, 16> Elts;
1812 
1813       if (StructType *STy = dyn_cast<StructType>(CurTy)) {
1814         for (unsigned i = 0; i != Size; ++i)
1815           Elts.push_back(ValueList.getConstantFwdRef(Record[i],
1816                                                      STy->getElementType(i)));
1817         V = ConstantStruct::get(STy, Elts);
1818       } else if (ArrayType *ATy = dyn_cast<ArrayType>(CurTy)) {
1819         Type *EltTy = ATy->getElementType();
1820         for (unsigned i = 0; i != Size; ++i)
1821           Elts.push_back(ValueList.getConstantFwdRef(Record[i], EltTy));
1822         V = ConstantArray::get(ATy, Elts);
1823       } else if (VectorType *VTy = dyn_cast<VectorType>(CurTy)) {
1824         Type *EltTy = VTy->getElementType();
1825         for (unsigned i = 0; i != Size; ++i)
1826           Elts.push_back(ValueList.getConstantFwdRef(Record[i], EltTy));
1827         V = ConstantVector::get(Elts);
1828       } else {
1829         V = UndefValue::get(CurTy);
1830       }
1831       break;
1832     }
1833     case bitc::CST_CODE_STRING:    // STRING: [values]
1834     case bitc::CST_CODE_CSTRING: { // CSTRING: [values]
1835       if (Record.empty())
1836         return Error("Invalid record");
1837 
1838       SmallString<16> Elts(Record.begin(), Record.end());
1839       V = ConstantDataArray::getString(Context, Elts,
1840                                        BitCode == bitc::CST_CODE_CSTRING);
1841       break;
1842     }
1843     case bitc::CST_CODE_DATA: {// DATA: [n x value]
1844       if (Record.empty())
1845         return Error("Invalid record");
1846 
1847       Type *EltTy = cast<SequentialType>(CurTy)->getElementType();
1848       unsigned Size = Record.size();
1849 
1850       if (EltTy->isIntegerTy(8)) {
1851         SmallVector<uint8_t, 16> Elts(Record.begin(), Record.end());
1852         if (isa<VectorType>(CurTy))
1853           V = ConstantDataVector::get(Context, Elts);
1854         else
1855           V = ConstantDataArray::get(Context, Elts);
1856       } else if (EltTy->isIntegerTy(16)) {
1857         SmallVector<uint16_t, 16> Elts(Record.begin(), Record.end());
1858         if (isa<VectorType>(CurTy))
1859           V = ConstantDataVector::get(Context, Elts);
1860         else
1861           V = ConstantDataArray::get(Context, Elts);
1862       } else if (EltTy->isIntegerTy(32)) {
1863         SmallVector<uint32_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(64)) {
1869         SmallVector<uint64_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->isFloatTy()) {
1875         SmallVector<float, 16> Elts(Size);
1876         std::transform(Record.begin(), Record.end(), Elts.begin(), BitsToFloat);
1877         if (isa<VectorType>(CurTy))
1878           V = ConstantDataVector::get(Context, Elts);
1879         else
1880           V = ConstantDataArray::get(Context, Elts);
1881       } else if (EltTy->isDoubleTy()) {
1882         SmallVector<double, 16> Elts(Size);
1883         std::transform(Record.begin(), Record.end(), Elts.begin(),
1884                        BitsToDouble);
1885         if (isa<VectorType>(CurTy))
1886           V = ConstantDataVector::get(Context, Elts);
1887         else
1888           V = ConstantDataArray::get(Context, Elts);
1889       } else {
1890         return Error("Invalid type for value");
1891       }
1892       break;
1893     }
1894 
1895     case bitc::CST_CODE_CE_BINOP: {  // CE_BINOP: [opcode, opval, opval]
1896       if (Record.size() < 3)
1897         return Error("Invalid record");
1898       int Opc = GetDecodedBinaryOpcode(Record[0], CurTy);
1899       if (Opc < 0) {
1900         V = UndefValue::get(CurTy);  // Unknown binop.
1901       } else {
1902         Constant *LHS = ValueList.getConstantFwdRef(Record[1], CurTy);
1903         Constant *RHS = ValueList.getConstantFwdRef(Record[2], CurTy);
1904         unsigned Flags = 0;
1905         if (Record.size() >= 4) {
1906           if (Opc == Instruction::Add ||
1907               Opc == Instruction::Sub ||
1908               Opc == Instruction::Mul ||
1909               Opc == Instruction::Shl) {
1910             if (Record[3] & (1 << bitc::OBO_NO_SIGNED_WRAP))
1911               Flags |= OverflowingBinaryOperator::NoSignedWrap;
1912             if (Record[3] & (1 << bitc::OBO_NO_UNSIGNED_WRAP))
1913               Flags |= OverflowingBinaryOperator::NoUnsignedWrap;
1914           } else if (Opc == Instruction::SDiv ||
1915                      Opc == Instruction::UDiv ||
1916                      Opc == Instruction::LShr ||
1917                      Opc == Instruction::AShr) {
1918             if (Record[3] & (1 << bitc::PEO_EXACT))
1919               Flags |= SDivOperator::IsExact;
1920           }
1921         }
1922         V = ConstantExpr::get(Opc, LHS, RHS, Flags);
1923       }
1924       break;
1925     }
1926     case bitc::CST_CODE_CE_CAST: {  // CE_CAST: [opcode, opty, opval]
1927       if (Record.size() < 3)
1928         return Error("Invalid record");
1929       int Opc = GetDecodedCastOpcode(Record[0]);
1930       if (Opc < 0) {
1931         V = UndefValue::get(CurTy);  // Unknown cast.
1932       } else {
1933         Type *OpTy = getTypeByID(Record[1]);
1934         if (!OpTy)
1935           return Error("Invalid record");
1936         Constant *Op = ValueList.getConstantFwdRef(Record[2], OpTy);
1937         V = UpgradeBitCastExpr(Opc, Op, CurTy);
1938         if (!V) V = ConstantExpr::getCast(Opc, Op, CurTy);
1939       }
1940       break;
1941     }
1942     case bitc::CST_CODE_CE_INBOUNDS_GEP:
1943     case bitc::CST_CODE_CE_GEP: {  // CE_GEP:        [n x operands]
1944       if (Record.size() & 1)
1945         return Error("Invalid record");
1946       SmallVector<Constant*, 16> Elts;
1947       for (unsigned i = 0, e = Record.size(); i != e; i += 2) {
1948         Type *ElTy = getTypeByID(Record[i]);
1949         if (!ElTy)
1950           return Error("Invalid record");
1951         Elts.push_back(ValueList.getConstantFwdRef(Record[i+1], ElTy));
1952       }
1953       ArrayRef<Constant *> Indices(Elts.begin() + 1, Elts.end());
1954       V = ConstantExpr::getGetElementPtr(Elts[0], Indices,
1955                                          BitCode ==
1956                                            bitc::CST_CODE_CE_INBOUNDS_GEP);
1957       break;
1958     }
1959     case bitc::CST_CODE_CE_SELECT: {  // CE_SELECT: [opval#, opval#, opval#]
1960       if (Record.size() < 3)
1961         return Error("Invalid record");
1962 
1963       Type *SelectorTy = Type::getInt1Ty(Context);
1964 
1965       // If CurTy is a vector of length n, then Record[0] must be a <n x i1>
1966       // vector. Otherwise, it must be a single bit.
1967       if (VectorType *VTy = dyn_cast<VectorType>(CurTy))
1968         SelectorTy = VectorType::get(Type::getInt1Ty(Context),
1969                                      VTy->getNumElements());
1970 
1971       V = ConstantExpr::getSelect(ValueList.getConstantFwdRef(Record[0],
1972                                                               SelectorTy),
1973                                   ValueList.getConstantFwdRef(Record[1],CurTy),
1974                                   ValueList.getConstantFwdRef(Record[2],CurTy));
1975       break;
1976     }
1977     case bitc::CST_CODE_CE_EXTRACTELT
1978         : { // CE_EXTRACTELT: [opty, opval, opty, opval]
1979       if (Record.size() < 3)
1980         return Error("Invalid record");
1981       VectorType *OpTy =
1982         dyn_cast_or_null<VectorType>(getTypeByID(Record[0]));
1983       if (!OpTy)
1984         return Error("Invalid record");
1985       Constant *Op0 = ValueList.getConstantFwdRef(Record[1], OpTy);
1986       Constant *Op1 = nullptr;
1987       if (Record.size() == 4) {
1988         Type *IdxTy = getTypeByID(Record[2]);
1989         if (!IdxTy)
1990           return Error("Invalid record");
1991         Op1 = ValueList.getConstantFwdRef(Record[3], IdxTy);
1992       } else // TODO: Remove with llvm 4.0
1993         Op1 = ValueList.getConstantFwdRef(Record[2], Type::getInt32Ty(Context));
1994       if (!Op1)
1995         return Error("Invalid record");
1996       V = ConstantExpr::getExtractElement(Op0, Op1);
1997       break;
1998     }
1999     case bitc::CST_CODE_CE_INSERTELT
2000         : { // CE_INSERTELT: [opval, opval, opty, opval]
2001       VectorType *OpTy = dyn_cast<VectorType>(CurTy);
2002       if (Record.size() < 3 || !OpTy)
2003         return Error("Invalid record");
2004       Constant *Op0 = ValueList.getConstantFwdRef(Record[0], OpTy);
2005       Constant *Op1 = ValueList.getConstantFwdRef(Record[1],
2006                                                   OpTy->getElementType());
2007       Constant *Op2 = nullptr;
2008       if (Record.size() == 4) {
2009         Type *IdxTy = getTypeByID(Record[2]);
2010         if (!IdxTy)
2011           return Error("Invalid record");
2012         Op2 = ValueList.getConstantFwdRef(Record[3], IdxTy);
2013       } else // TODO: Remove with llvm 4.0
2014         Op2 = ValueList.getConstantFwdRef(Record[2], Type::getInt32Ty(Context));
2015       if (!Op2)
2016         return Error("Invalid record");
2017       V = ConstantExpr::getInsertElement(Op0, Op1, Op2);
2018       break;
2019     }
2020     case bitc::CST_CODE_CE_SHUFFLEVEC: { // CE_SHUFFLEVEC: [opval, opval, opval]
2021       VectorType *OpTy = dyn_cast<VectorType>(CurTy);
2022       if (Record.size() < 3 || !OpTy)
2023         return Error("Invalid record");
2024       Constant *Op0 = ValueList.getConstantFwdRef(Record[0], OpTy);
2025       Constant *Op1 = ValueList.getConstantFwdRef(Record[1], OpTy);
2026       Type *ShufTy = VectorType::get(Type::getInt32Ty(Context),
2027                                                  OpTy->getNumElements());
2028       Constant *Op2 = ValueList.getConstantFwdRef(Record[2], ShufTy);
2029       V = ConstantExpr::getShuffleVector(Op0, Op1, Op2);
2030       break;
2031     }
2032     case bitc::CST_CODE_CE_SHUFVEC_EX: { // [opty, opval, opval, opval]
2033       VectorType *RTy = dyn_cast<VectorType>(CurTy);
2034       VectorType *OpTy =
2035         dyn_cast_or_null<VectorType>(getTypeByID(Record[0]));
2036       if (Record.size() < 4 || !RTy || !OpTy)
2037         return Error("Invalid record");
2038       Constant *Op0 = ValueList.getConstantFwdRef(Record[1], OpTy);
2039       Constant *Op1 = ValueList.getConstantFwdRef(Record[2], OpTy);
2040       Type *ShufTy = VectorType::get(Type::getInt32Ty(Context),
2041                                                  RTy->getNumElements());
2042       Constant *Op2 = ValueList.getConstantFwdRef(Record[3], ShufTy);
2043       V = ConstantExpr::getShuffleVector(Op0, Op1, Op2);
2044       break;
2045     }
2046     case bitc::CST_CODE_CE_CMP: {     // CE_CMP: [opty, opval, opval, pred]
2047       if (Record.size() < 4)
2048         return Error("Invalid record");
2049       Type *OpTy = getTypeByID(Record[0]);
2050       if (!OpTy)
2051         return Error("Invalid record");
2052       Constant *Op0 = ValueList.getConstantFwdRef(Record[1], OpTy);
2053       Constant *Op1 = ValueList.getConstantFwdRef(Record[2], OpTy);
2054 
2055       if (OpTy->isFPOrFPVectorTy())
2056         V = ConstantExpr::getFCmp(Record[3], Op0, Op1);
2057       else
2058         V = ConstantExpr::getICmp(Record[3], Op0, Op1);
2059       break;
2060     }
2061     // This maintains backward compatibility, pre-asm dialect keywords.
2062     // FIXME: Remove with the 4.0 release.
2063     case bitc::CST_CODE_INLINEASM_OLD: {
2064       if (Record.size() < 2)
2065         return Error("Invalid record");
2066       std::string AsmStr, ConstrStr;
2067       bool HasSideEffects = Record[0] & 1;
2068       bool IsAlignStack = Record[0] >> 1;
2069       unsigned AsmStrSize = Record[1];
2070       if (2+AsmStrSize >= Record.size())
2071         return Error("Invalid record");
2072       unsigned ConstStrSize = Record[2+AsmStrSize];
2073       if (3+AsmStrSize+ConstStrSize > Record.size())
2074         return Error("Invalid record");
2075 
2076       for (unsigned i = 0; i != AsmStrSize; ++i)
2077         AsmStr += (char)Record[2+i];
2078       for (unsigned i = 0; i != ConstStrSize; ++i)
2079         ConstrStr += (char)Record[3+AsmStrSize+i];
2080       PointerType *PTy = cast<PointerType>(CurTy);
2081       V = InlineAsm::get(cast<FunctionType>(PTy->getElementType()),
2082                          AsmStr, ConstrStr, HasSideEffects, IsAlignStack);
2083       break;
2084     }
2085     // This version adds support for the asm dialect keywords (e.g.,
2086     // inteldialect).
2087     case bitc::CST_CODE_INLINEASM: {
2088       if (Record.size() < 2)
2089         return Error("Invalid record");
2090       std::string AsmStr, ConstrStr;
2091       bool HasSideEffects = Record[0] & 1;
2092       bool IsAlignStack = (Record[0] >> 1) & 1;
2093       unsigned AsmDialect = Record[0] >> 2;
2094       unsigned AsmStrSize = Record[1];
2095       if (2+AsmStrSize >= Record.size())
2096         return Error("Invalid record");
2097       unsigned ConstStrSize = Record[2+AsmStrSize];
2098       if (3+AsmStrSize+ConstStrSize > Record.size())
2099         return Error("Invalid record");
2100 
2101       for (unsigned i = 0; i != AsmStrSize; ++i)
2102         AsmStr += (char)Record[2+i];
2103       for (unsigned i = 0; i != ConstStrSize; ++i)
2104         ConstrStr += (char)Record[3+AsmStrSize+i];
2105       PointerType *PTy = cast<PointerType>(CurTy);
2106       V = InlineAsm::get(cast<FunctionType>(PTy->getElementType()),
2107                          AsmStr, ConstrStr, HasSideEffects, IsAlignStack,
2108                          InlineAsm::AsmDialect(AsmDialect));
2109       break;
2110     }
2111     case bitc::CST_CODE_BLOCKADDRESS:{
2112       if (Record.size() < 3)
2113         return Error("Invalid record");
2114       Type *FnTy = getTypeByID(Record[0]);
2115       if (!FnTy)
2116         return Error("Invalid record");
2117       Function *Fn =
2118         dyn_cast_or_null<Function>(ValueList.getConstantFwdRef(Record[1],FnTy));
2119       if (!Fn)
2120         return Error("Invalid record");
2121 
2122       // Don't let Fn get dematerialized.
2123       BlockAddressesTaken.insert(Fn);
2124 
2125       // If the function is already parsed we can insert the block address right
2126       // away.
2127       BasicBlock *BB;
2128       unsigned BBID = Record[2];
2129       if (!BBID)
2130         // Invalid reference to entry block.
2131         return Error("Invalid ID");
2132       if (!Fn->empty()) {
2133         Function::iterator BBI = Fn->begin(), BBE = Fn->end();
2134         for (size_t I = 0, E = BBID; I != E; ++I) {
2135           if (BBI == BBE)
2136             return Error("Invalid ID");
2137           ++BBI;
2138         }
2139         BB = BBI;
2140       } else {
2141         // Otherwise insert a placeholder and remember it so it can be inserted
2142         // when the function is parsed.
2143         auto &FwdBBs = BasicBlockFwdRefs[Fn];
2144         if (FwdBBs.empty())
2145           BasicBlockFwdRefQueue.push_back(Fn);
2146         if (FwdBBs.size() < BBID + 1)
2147           FwdBBs.resize(BBID + 1);
2148         if (!FwdBBs[BBID])
2149           FwdBBs[BBID] = BasicBlock::Create(Context);
2150         BB = FwdBBs[BBID];
2151       }
2152       V = BlockAddress::get(Fn, BB);
2153       break;
2154     }
2155     }
2156 
2157     ValueList.AssignValue(V, NextCstNo);
2158     ++NextCstNo;
2159   }
2160 }
2161 
2162 std::error_code BitcodeReader::ParseUseLists() {
2163   if (Stream.EnterSubBlock(bitc::USELIST_BLOCK_ID))
2164     return Error("Invalid record");
2165 
2166   // Read all the records.
2167   SmallVector<uint64_t, 64> Record;
2168   while (1) {
2169     BitstreamEntry Entry = Stream.advanceSkippingSubblocks();
2170 
2171     switch (Entry.Kind) {
2172     case BitstreamEntry::SubBlock: // Handled for us already.
2173     case BitstreamEntry::Error:
2174       return Error("Malformed block");
2175     case BitstreamEntry::EndBlock:
2176       return std::error_code();
2177     case BitstreamEntry::Record:
2178       // The interesting case.
2179       break;
2180     }
2181 
2182     // Read a use list record.
2183     Record.clear();
2184     bool IsBB = false;
2185     switch (Stream.readRecord(Entry.ID, Record)) {
2186     default:  // Default behavior: unknown type.
2187       break;
2188     case bitc::USELIST_CODE_BB:
2189       IsBB = true;
2190       // fallthrough
2191     case bitc::USELIST_CODE_DEFAULT: {
2192       unsigned RecordLength = Record.size();
2193       if (RecordLength < 3)
2194         // Records should have at least an ID and two indexes.
2195         return Error("Invalid record");
2196       unsigned ID = Record.back();
2197       Record.pop_back();
2198 
2199       Value *V;
2200       if (IsBB) {
2201         assert(ID < FunctionBBs.size() && "Basic block not found");
2202         V = FunctionBBs[ID];
2203       } else
2204         V = ValueList[ID];
2205       unsigned NumUses = 0;
2206       SmallDenseMap<const Use *, unsigned, 16> Order;
2207       for (const Use &U : V->uses()) {
2208         if (++NumUses > Record.size())
2209           break;
2210         Order[&U] = Record[NumUses - 1];
2211       }
2212       if (Order.size() != Record.size() || NumUses > Record.size())
2213         // Mismatches can happen if the functions are being materialized lazily
2214         // (out-of-order), or a value has been upgraded.
2215         break;
2216 
2217       V->sortUseList([&](const Use &L, const Use &R) {
2218         return Order.lookup(&L) < Order.lookup(&R);
2219       });
2220       break;
2221     }
2222     }
2223   }
2224 }
2225 
2226 /// RememberAndSkipFunctionBody - When we see the block for a function body,
2227 /// remember where it is and then skip it.  This lets us lazily deserialize the
2228 /// functions.
2229 std::error_code BitcodeReader::RememberAndSkipFunctionBody() {
2230   // Get the function we are talking about.
2231   if (FunctionsWithBodies.empty())
2232     return Error("Insufficient function protos");
2233 
2234   Function *Fn = FunctionsWithBodies.back();
2235   FunctionsWithBodies.pop_back();
2236 
2237   // Save the current stream state.
2238   uint64_t CurBit = Stream.GetCurrentBitNo();
2239   DeferredFunctionInfo[Fn] = CurBit;
2240 
2241   // Skip over the function block for now.
2242   if (Stream.SkipBlock())
2243     return Error("Invalid record");
2244   return std::error_code();
2245 }
2246 
2247 std::error_code BitcodeReader::GlobalCleanup() {
2248   // Patch the initializers for globals and aliases up.
2249   ResolveGlobalAndAliasInits();
2250   if (!GlobalInits.empty() || !AliasInits.empty())
2251     return Error("Malformed global initializer set");
2252 
2253   // Look for intrinsic functions which need to be upgraded at some point
2254   for (Module::iterator FI = TheModule->begin(), FE = TheModule->end();
2255        FI != FE; ++FI) {
2256     Function *NewFn;
2257     if (UpgradeIntrinsicFunction(FI, NewFn))
2258       UpgradedIntrinsics.push_back(std::make_pair(FI, NewFn));
2259   }
2260 
2261   // Look for global variables which need to be renamed.
2262   for (Module::global_iterator
2263          GI = TheModule->global_begin(), GE = TheModule->global_end();
2264        GI != GE;) {
2265     GlobalVariable *GV = GI++;
2266     UpgradeGlobalVariable(GV);
2267   }
2268 
2269   // Force deallocation of memory for these vectors to favor the client that
2270   // want lazy deserialization.
2271   std::vector<std::pair<GlobalVariable*, unsigned> >().swap(GlobalInits);
2272   std::vector<std::pair<GlobalAlias*, unsigned> >().swap(AliasInits);
2273   return std::error_code();
2274 }
2275 
2276 std::error_code BitcodeReader::ParseModule(bool Resume) {
2277   if (Resume)
2278     Stream.JumpToBit(NextUnreadBit);
2279   else if (Stream.EnterSubBlock(bitc::MODULE_BLOCK_ID))
2280     return Error("Invalid record");
2281 
2282   SmallVector<uint64_t, 64> Record;
2283   std::vector<std::string> SectionTable;
2284   std::vector<std::string> GCTable;
2285 
2286   // Read all the records for this module.
2287   while (1) {
2288     BitstreamEntry Entry = Stream.advance();
2289 
2290     switch (Entry.Kind) {
2291     case BitstreamEntry::Error:
2292       return Error("Malformed block");
2293     case BitstreamEntry::EndBlock:
2294       return GlobalCleanup();
2295 
2296     case BitstreamEntry::SubBlock:
2297       switch (Entry.ID) {
2298       default:  // Skip unknown content.
2299         if (Stream.SkipBlock())
2300           return Error("Invalid record");
2301         break;
2302       case bitc::BLOCKINFO_BLOCK_ID:
2303         if (Stream.ReadBlockInfoBlock())
2304           return Error("Malformed block");
2305         break;
2306       case bitc::PARAMATTR_BLOCK_ID:
2307         if (std::error_code EC = ParseAttributeBlock())
2308           return EC;
2309         break;
2310       case bitc::PARAMATTR_GROUP_BLOCK_ID:
2311         if (std::error_code EC = ParseAttributeGroupBlock())
2312           return EC;
2313         break;
2314       case bitc::TYPE_BLOCK_ID_NEW:
2315         if (std::error_code EC = ParseTypeTable())
2316           return EC;
2317         break;
2318       case bitc::VALUE_SYMTAB_BLOCK_ID:
2319         if (std::error_code EC = ParseValueSymbolTable())
2320           return EC;
2321         SeenValueSymbolTable = true;
2322         break;
2323       case bitc::CONSTANTS_BLOCK_ID:
2324         if (std::error_code EC = ParseConstants())
2325           return EC;
2326         if (std::error_code EC = ResolveGlobalAndAliasInits())
2327           return EC;
2328         break;
2329       case bitc::METADATA_BLOCK_ID:
2330         if (std::error_code EC = ParseMetadata())
2331           return EC;
2332         break;
2333       case bitc::FUNCTION_BLOCK_ID:
2334         // If this is the first function body we've seen, reverse the
2335         // FunctionsWithBodies list.
2336         if (!SeenFirstFunctionBody) {
2337           std::reverse(FunctionsWithBodies.begin(), FunctionsWithBodies.end());
2338           if (std::error_code EC = GlobalCleanup())
2339             return EC;
2340           SeenFirstFunctionBody = true;
2341         }
2342 
2343         if (std::error_code EC = RememberAndSkipFunctionBody())
2344           return EC;
2345         // For streaming bitcode, suspend parsing when we reach the function
2346         // bodies. Subsequent materialization calls will resume it when
2347         // necessary. For streaming, the function bodies must be at the end of
2348         // the bitcode. If the bitcode file is old, the symbol table will be
2349         // at the end instead and will not have been seen yet. In this case,
2350         // just finish the parse now.
2351         if (LazyStreamer && SeenValueSymbolTable) {
2352           NextUnreadBit = Stream.GetCurrentBitNo();
2353           return std::error_code();
2354         }
2355         break;
2356       case bitc::USELIST_BLOCK_ID:
2357         if (std::error_code EC = ParseUseLists())
2358           return EC;
2359         break;
2360       }
2361       continue;
2362 
2363     case BitstreamEntry::Record:
2364       // The interesting case.
2365       break;
2366     }
2367 
2368 
2369     // Read a record.
2370     switch (Stream.readRecord(Entry.ID, Record)) {
2371     default: break;  // Default behavior, ignore unknown content.
2372     case bitc::MODULE_CODE_VERSION: {  // VERSION: [version#]
2373       if (Record.size() < 1)
2374         return Error("Invalid record");
2375       // Only version #0 and #1 are supported so far.
2376       unsigned module_version = Record[0];
2377       switch (module_version) {
2378         default:
2379           return Error("Invalid value");
2380         case 0:
2381           UseRelativeIDs = false;
2382           break;
2383         case 1:
2384           UseRelativeIDs = true;
2385           break;
2386       }
2387       break;
2388     }
2389     case bitc::MODULE_CODE_TRIPLE: {  // TRIPLE: [strchr x N]
2390       std::string S;
2391       if (ConvertToString(Record, 0, S))
2392         return Error("Invalid record");
2393       TheModule->setTargetTriple(S);
2394       break;
2395     }
2396     case bitc::MODULE_CODE_DATALAYOUT: {  // DATALAYOUT: [strchr x N]
2397       std::string S;
2398       if (ConvertToString(Record, 0, S))
2399         return Error("Invalid record");
2400       TheModule->setDataLayout(S);
2401       break;
2402     }
2403     case bitc::MODULE_CODE_ASM: {  // ASM: [strchr x N]
2404       std::string S;
2405       if (ConvertToString(Record, 0, S))
2406         return Error("Invalid record");
2407       TheModule->setModuleInlineAsm(S);
2408       break;
2409     }
2410     case bitc::MODULE_CODE_DEPLIB: {  // DEPLIB: [strchr x N]
2411       // FIXME: Remove in 4.0.
2412       std::string S;
2413       if (ConvertToString(Record, 0, S))
2414         return Error("Invalid record");
2415       // Ignore value.
2416       break;
2417     }
2418     case bitc::MODULE_CODE_SECTIONNAME: {  // SECTIONNAME: [strchr x N]
2419       std::string S;
2420       if (ConvertToString(Record, 0, S))
2421         return Error("Invalid record");
2422       SectionTable.push_back(S);
2423       break;
2424     }
2425     case bitc::MODULE_CODE_GCNAME: {  // SECTIONNAME: [strchr x N]
2426       std::string S;
2427       if (ConvertToString(Record, 0, S))
2428         return Error("Invalid record");
2429       GCTable.push_back(S);
2430       break;
2431     }
2432     case bitc::MODULE_CODE_COMDAT: { // COMDAT: [selection_kind, name]
2433       if (Record.size() < 2)
2434         return Error("Invalid record");
2435       Comdat::SelectionKind SK = getDecodedComdatSelectionKind(Record[0]);
2436       unsigned ComdatNameSize = Record[1];
2437       std::string ComdatName;
2438       ComdatName.reserve(ComdatNameSize);
2439       for (unsigned i = 0; i != ComdatNameSize; ++i)
2440         ComdatName += (char)Record[2 + i];
2441       Comdat *C = TheModule->getOrInsertComdat(ComdatName);
2442       C->setSelectionKind(SK);
2443       ComdatList.push_back(C);
2444       break;
2445     }
2446     // GLOBALVAR: [pointer type, isconst, initid,
2447     //             linkage, alignment, section, visibility, threadlocal,
2448     //             unnamed_addr, externally_initialized, dllstorageclass,
2449     //             comdat]
2450     case bitc::MODULE_CODE_GLOBALVAR: {
2451       if (Record.size() < 6)
2452         return Error("Invalid record");
2453       Type *Ty = getTypeByID(Record[0]);
2454       if (!Ty)
2455         return Error("Invalid record");
2456       if (!Ty->isPointerTy())
2457         return Error("Invalid type for value");
2458       unsigned AddressSpace = cast<PointerType>(Ty)->getAddressSpace();
2459       Ty = cast<PointerType>(Ty)->getElementType();
2460 
2461       bool isConstant = Record[1];
2462       uint64_t RawLinkage = Record[3];
2463       GlobalValue::LinkageTypes Linkage = getDecodedLinkage(RawLinkage);
2464       unsigned Alignment = (1 << Record[4]) >> 1;
2465       std::string Section;
2466       if (Record[5]) {
2467         if (Record[5]-1 >= SectionTable.size())
2468           return Error("Invalid ID");
2469         Section = SectionTable[Record[5]-1];
2470       }
2471       GlobalValue::VisibilityTypes Visibility = GlobalValue::DefaultVisibility;
2472       // Local linkage must have default visibility.
2473       if (Record.size() > 6 && !GlobalValue::isLocalLinkage(Linkage))
2474         // FIXME: Change to an error if non-default in 4.0.
2475         Visibility = GetDecodedVisibility(Record[6]);
2476 
2477       GlobalVariable::ThreadLocalMode TLM = GlobalVariable::NotThreadLocal;
2478       if (Record.size() > 7)
2479         TLM = GetDecodedThreadLocalMode(Record[7]);
2480 
2481       bool UnnamedAddr = false;
2482       if (Record.size() > 8)
2483         UnnamedAddr = Record[8];
2484 
2485       bool ExternallyInitialized = false;
2486       if (Record.size() > 9)
2487         ExternallyInitialized = Record[9];
2488 
2489       GlobalVariable *NewGV =
2490         new GlobalVariable(*TheModule, Ty, isConstant, Linkage, nullptr, "", nullptr,
2491                            TLM, AddressSpace, ExternallyInitialized);
2492       NewGV->setAlignment(Alignment);
2493       if (!Section.empty())
2494         NewGV->setSection(Section);
2495       NewGV->setVisibility(Visibility);
2496       NewGV->setUnnamedAddr(UnnamedAddr);
2497 
2498       if (Record.size() > 10)
2499         NewGV->setDLLStorageClass(GetDecodedDLLStorageClass(Record[10]));
2500       else
2501         UpgradeDLLImportExportLinkage(NewGV, RawLinkage);
2502 
2503       ValueList.push_back(NewGV);
2504 
2505       // Remember which value to use for the global initializer.
2506       if (unsigned InitID = Record[2])
2507         GlobalInits.push_back(std::make_pair(NewGV, InitID-1));
2508 
2509       if (Record.size() > 11) {
2510         if (unsigned ComdatID = Record[11]) {
2511           assert(ComdatID <= ComdatList.size());
2512           NewGV->setComdat(ComdatList[ComdatID - 1]);
2513         }
2514       } else if (hasImplicitComdat(RawLinkage)) {
2515         NewGV->setComdat(reinterpret_cast<Comdat *>(1));
2516       }
2517       break;
2518     }
2519     // FUNCTION:  [type, callingconv, isproto, linkage, paramattr,
2520     //             alignment, section, visibility, gc, unnamed_addr,
2521     //             prologuedata, dllstorageclass, comdat, prefixdata]
2522     case bitc::MODULE_CODE_FUNCTION: {
2523       if (Record.size() < 8)
2524         return Error("Invalid record");
2525       Type *Ty = getTypeByID(Record[0]);
2526       if (!Ty)
2527         return Error("Invalid record");
2528       if (!Ty->isPointerTy())
2529         return Error("Invalid type for value");
2530       FunctionType *FTy =
2531         dyn_cast<FunctionType>(cast<PointerType>(Ty)->getElementType());
2532       if (!FTy)
2533         return Error("Invalid type for value");
2534 
2535       Function *Func = Function::Create(FTy, GlobalValue::ExternalLinkage,
2536                                         "", TheModule);
2537 
2538       Func->setCallingConv(static_cast<CallingConv::ID>(Record[1]));
2539       bool isProto = Record[2];
2540       uint64_t RawLinkage = Record[3];
2541       Func->setLinkage(getDecodedLinkage(RawLinkage));
2542       Func->setAttributes(getAttributes(Record[4]));
2543 
2544       Func->setAlignment((1 << Record[5]) >> 1);
2545       if (Record[6]) {
2546         if (Record[6]-1 >= SectionTable.size())
2547           return Error("Invalid ID");
2548         Func->setSection(SectionTable[Record[6]-1]);
2549       }
2550       // Local linkage must have default visibility.
2551       if (!Func->hasLocalLinkage())
2552         // FIXME: Change to an error if non-default in 4.0.
2553         Func->setVisibility(GetDecodedVisibility(Record[7]));
2554       if (Record.size() > 8 && Record[8]) {
2555         if (Record[8]-1 > GCTable.size())
2556           return Error("Invalid ID");
2557         Func->setGC(GCTable[Record[8]-1].c_str());
2558       }
2559       bool UnnamedAddr = false;
2560       if (Record.size() > 9)
2561         UnnamedAddr = Record[9];
2562       Func->setUnnamedAddr(UnnamedAddr);
2563       if (Record.size() > 10 && Record[10] != 0)
2564         FunctionPrologues.push_back(std::make_pair(Func, Record[10]-1));
2565 
2566       if (Record.size() > 11)
2567         Func->setDLLStorageClass(GetDecodedDLLStorageClass(Record[11]));
2568       else
2569         UpgradeDLLImportExportLinkage(Func, RawLinkage);
2570 
2571       if (Record.size() > 12) {
2572         if (unsigned ComdatID = Record[12]) {
2573           assert(ComdatID <= ComdatList.size());
2574           Func->setComdat(ComdatList[ComdatID - 1]);
2575         }
2576       } else if (hasImplicitComdat(RawLinkage)) {
2577         Func->setComdat(reinterpret_cast<Comdat *>(1));
2578       }
2579 
2580       if (Record.size() > 13 && Record[13] != 0)
2581         FunctionPrefixes.push_back(std::make_pair(Func, Record[13]-1));
2582 
2583       ValueList.push_back(Func);
2584 
2585       // If this is a function with a body, remember the prototype we are
2586       // creating now, so that we can match up the body with them later.
2587       if (!isProto) {
2588         Func->setIsMaterializable(true);
2589         FunctionsWithBodies.push_back(Func);
2590         if (LazyStreamer)
2591           DeferredFunctionInfo[Func] = 0;
2592       }
2593       break;
2594     }
2595     // ALIAS: [alias type, aliasee val#, linkage]
2596     // ALIAS: [alias type, aliasee val#, linkage, visibility, dllstorageclass]
2597     case bitc::MODULE_CODE_ALIAS: {
2598       if (Record.size() < 3)
2599         return Error("Invalid record");
2600       Type *Ty = getTypeByID(Record[0]);
2601       if (!Ty)
2602         return Error("Invalid record");
2603       auto *PTy = dyn_cast<PointerType>(Ty);
2604       if (!PTy)
2605         return Error("Invalid type for value");
2606 
2607       auto *NewGA =
2608           GlobalAlias::create(PTy->getElementType(), PTy->getAddressSpace(),
2609                               getDecodedLinkage(Record[2]), "", TheModule);
2610       // Old bitcode files didn't have visibility field.
2611       // Local linkage must have default visibility.
2612       if (Record.size() > 3 && !NewGA->hasLocalLinkage())
2613         // FIXME: Change to an error if non-default in 4.0.
2614         NewGA->setVisibility(GetDecodedVisibility(Record[3]));
2615       if (Record.size() > 4)
2616         NewGA->setDLLStorageClass(GetDecodedDLLStorageClass(Record[4]));
2617       else
2618         UpgradeDLLImportExportLinkage(NewGA, Record[2]);
2619       if (Record.size() > 5)
2620         NewGA->setThreadLocalMode(GetDecodedThreadLocalMode(Record[5]));
2621       if (Record.size() > 6)
2622         NewGA->setUnnamedAddr(Record[6]);
2623       ValueList.push_back(NewGA);
2624       AliasInits.push_back(std::make_pair(NewGA, Record[1]));
2625       break;
2626     }
2627     /// MODULE_CODE_PURGEVALS: [numvals]
2628     case bitc::MODULE_CODE_PURGEVALS:
2629       // Trim down the value list to the specified size.
2630       if (Record.size() < 1 || Record[0] > ValueList.size())
2631         return Error("Invalid record");
2632       ValueList.shrinkTo(Record[0]);
2633       break;
2634     }
2635     Record.clear();
2636   }
2637 }
2638 
2639 std::error_code BitcodeReader::ParseBitcodeInto(Module *M) {
2640   TheModule = nullptr;
2641 
2642   if (std::error_code EC = InitStream())
2643     return EC;
2644 
2645   // Sniff for the signature.
2646   if (Stream.Read(8) != 'B' ||
2647       Stream.Read(8) != 'C' ||
2648       Stream.Read(4) != 0x0 ||
2649       Stream.Read(4) != 0xC ||
2650       Stream.Read(4) != 0xE ||
2651       Stream.Read(4) != 0xD)
2652     return Error("Invalid bitcode signature");
2653 
2654   // We expect a number of well-defined blocks, though we don't necessarily
2655   // need to understand them all.
2656   while (1) {
2657     if (Stream.AtEndOfStream())
2658       return std::error_code();
2659 
2660     BitstreamEntry Entry =
2661       Stream.advance(BitstreamCursor::AF_DontAutoprocessAbbrevs);
2662 
2663     switch (Entry.Kind) {
2664     case BitstreamEntry::Error:
2665       return Error("Malformed block");
2666     case BitstreamEntry::EndBlock:
2667       return std::error_code();
2668 
2669     case BitstreamEntry::SubBlock:
2670       switch (Entry.ID) {
2671       case bitc::BLOCKINFO_BLOCK_ID:
2672         if (Stream.ReadBlockInfoBlock())
2673           return Error("Malformed block");
2674         break;
2675       case bitc::MODULE_BLOCK_ID:
2676         // Reject multiple MODULE_BLOCK's in a single bitstream.
2677         if (TheModule)
2678           return Error("Invalid multiple blocks");
2679         TheModule = M;
2680         if (std::error_code EC = ParseModule(false))
2681           return EC;
2682         if (LazyStreamer)
2683           return std::error_code();
2684         break;
2685       default:
2686         if (Stream.SkipBlock())
2687           return Error("Invalid record");
2688         break;
2689       }
2690       continue;
2691     case BitstreamEntry::Record:
2692       // There should be no records in the top-level of blocks.
2693 
2694       // The ranlib in Xcode 4 will align archive members by appending newlines
2695       // to the end of them. If this file size is a multiple of 4 but not 8, we
2696       // have to read and ignore these final 4 bytes :-(
2697       if (Stream.getAbbrevIDWidth() == 2 && Entry.ID == 2 &&
2698           Stream.Read(6) == 2 && Stream.Read(24) == 0xa0a0a &&
2699           Stream.AtEndOfStream())
2700         return std::error_code();
2701 
2702       return Error("Invalid record");
2703     }
2704   }
2705 }
2706 
2707 ErrorOr<std::string> BitcodeReader::parseModuleTriple() {
2708   if (Stream.EnterSubBlock(bitc::MODULE_BLOCK_ID))
2709     return Error("Invalid record");
2710 
2711   SmallVector<uint64_t, 64> Record;
2712 
2713   std::string Triple;
2714   // Read all the records for this module.
2715   while (1) {
2716     BitstreamEntry Entry = Stream.advanceSkippingSubblocks();
2717 
2718     switch (Entry.Kind) {
2719     case BitstreamEntry::SubBlock: // Handled for us already.
2720     case BitstreamEntry::Error:
2721       return Error("Malformed block");
2722     case BitstreamEntry::EndBlock:
2723       return Triple;
2724     case BitstreamEntry::Record:
2725       // The interesting case.
2726       break;
2727     }
2728 
2729     // Read a record.
2730     switch (Stream.readRecord(Entry.ID, Record)) {
2731     default: break;  // Default behavior, ignore unknown content.
2732     case bitc::MODULE_CODE_TRIPLE: {  // TRIPLE: [strchr x N]
2733       std::string S;
2734       if (ConvertToString(Record, 0, S))
2735         return Error("Invalid record");
2736       Triple = S;
2737       break;
2738     }
2739     }
2740     Record.clear();
2741   }
2742   llvm_unreachable("Exit infinite loop");
2743 }
2744 
2745 ErrorOr<std::string> BitcodeReader::parseTriple() {
2746   if (std::error_code EC = InitStream())
2747     return EC;
2748 
2749   // Sniff for the signature.
2750   if (Stream.Read(8) != 'B' ||
2751       Stream.Read(8) != 'C' ||
2752       Stream.Read(4) != 0x0 ||
2753       Stream.Read(4) != 0xC ||
2754       Stream.Read(4) != 0xE ||
2755       Stream.Read(4) != 0xD)
2756     return Error("Invalid bitcode signature");
2757 
2758   // We expect a number of well-defined blocks, though we don't necessarily
2759   // need to understand them all.
2760   while (1) {
2761     BitstreamEntry Entry = Stream.advance();
2762 
2763     switch (Entry.Kind) {
2764     case BitstreamEntry::Error:
2765       return Error("Malformed block");
2766     case BitstreamEntry::EndBlock:
2767       return std::error_code();
2768 
2769     case BitstreamEntry::SubBlock:
2770       if (Entry.ID == bitc::MODULE_BLOCK_ID)
2771         return parseModuleTriple();
2772 
2773       // Ignore other sub-blocks.
2774       if (Stream.SkipBlock())
2775         return Error("Malformed block");
2776       continue;
2777 
2778     case BitstreamEntry::Record:
2779       Stream.skipRecord(Entry.ID);
2780       continue;
2781     }
2782   }
2783 }
2784 
2785 /// ParseMetadataAttachment - Parse metadata attachments.
2786 std::error_code BitcodeReader::ParseMetadataAttachment() {
2787   if (Stream.EnterSubBlock(bitc::METADATA_ATTACHMENT_ID))
2788     return Error("Invalid record");
2789 
2790   SmallVector<uint64_t, 64> Record;
2791   while (1) {
2792     BitstreamEntry Entry = Stream.advanceSkippingSubblocks();
2793 
2794     switch (Entry.Kind) {
2795     case BitstreamEntry::SubBlock: // Handled for us already.
2796     case BitstreamEntry::Error:
2797       return Error("Malformed block");
2798     case BitstreamEntry::EndBlock:
2799       return std::error_code();
2800     case BitstreamEntry::Record:
2801       // The interesting case.
2802       break;
2803     }
2804 
2805     // Read a metadata attachment record.
2806     Record.clear();
2807     switch (Stream.readRecord(Entry.ID, Record)) {
2808     default:  // Default behavior: ignore.
2809       break;
2810     case bitc::METADATA_ATTACHMENT: {
2811       unsigned RecordLength = Record.size();
2812       if (Record.empty() || (RecordLength - 1) % 2 == 1)
2813         return Error("Invalid record");
2814       Instruction *Inst = InstructionList[Record[0]];
2815       for (unsigned i = 1; i != RecordLength; i = i+2) {
2816         unsigned Kind = Record[i];
2817         DenseMap<unsigned, unsigned>::iterator I =
2818           MDKindMap.find(Kind);
2819         if (I == MDKindMap.end())
2820           return Error("Invalid ID");
2821         Metadata *Node = MDValueList.getValueFwdRef(Record[i + 1]);
2822         if (isa<LocalAsMetadata>(Node))
2823           // Drop the attachment.  This used to be legal, but there's no
2824           // upgrade path.
2825           break;
2826         Inst->setMetadata(I->second, cast<MDNode>(Node));
2827         if (I->second == LLVMContext::MD_tbaa)
2828           InstsWithTBAATag.push_back(Inst);
2829       }
2830       break;
2831     }
2832     }
2833   }
2834 }
2835 
2836 /// ParseFunctionBody - Lazily parse the specified function body block.
2837 std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
2838   if (Stream.EnterSubBlock(bitc::FUNCTION_BLOCK_ID))
2839     return Error("Invalid record");
2840 
2841   InstructionList.clear();
2842   unsigned ModuleValueListSize = ValueList.size();
2843   unsigned ModuleMDValueListSize = MDValueList.size();
2844 
2845   // Add all the function arguments to the value table.
2846   for(Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); I != E; ++I)
2847     ValueList.push_back(I);
2848 
2849   unsigned NextValueNo = ValueList.size();
2850   BasicBlock *CurBB = nullptr;
2851   unsigned CurBBNo = 0;
2852 
2853   DebugLoc LastLoc;
2854   auto getLastInstruction = [&]() -> Instruction * {
2855     if (CurBB && !CurBB->empty())
2856       return &CurBB->back();
2857     else if (CurBBNo && FunctionBBs[CurBBNo - 1] &&
2858              !FunctionBBs[CurBBNo - 1]->empty())
2859       return &FunctionBBs[CurBBNo - 1]->back();
2860     return nullptr;
2861   };
2862 
2863   // Read all the records.
2864   SmallVector<uint64_t, 64> Record;
2865   while (1) {
2866     BitstreamEntry Entry = Stream.advance();
2867 
2868     switch (Entry.Kind) {
2869     case BitstreamEntry::Error:
2870       return Error("Malformed block");
2871     case BitstreamEntry::EndBlock:
2872       goto OutOfRecordLoop;
2873 
2874     case BitstreamEntry::SubBlock:
2875       switch (Entry.ID) {
2876       default:  // Skip unknown content.
2877         if (Stream.SkipBlock())
2878           return Error("Invalid record");
2879         break;
2880       case bitc::CONSTANTS_BLOCK_ID:
2881         if (std::error_code EC = ParseConstants())
2882           return EC;
2883         NextValueNo = ValueList.size();
2884         break;
2885       case bitc::VALUE_SYMTAB_BLOCK_ID:
2886         if (std::error_code EC = ParseValueSymbolTable())
2887           return EC;
2888         break;
2889       case bitc::METADATA_ATTACHMENT_ID:
2890         if (std::error_code EC = ParseMetadataAttachment())
2891           return EC;
2892         break;
2893       case bitc::METADATA_BLOCK_ID:
2894         if (std::error_code EC = ParseMetadata())
2895           return EC;
2896         break;
2897       case bitc::USELIST_BLOCK_ID:
2898         if (std::error_code EC = ParseUseLists())
2899           return EC;
2900         break;
2901       }
2902       continue;
2903 
2904     case BitstreamEntry::Record:
2905       // The interesting case.
2906       break;
2907     }
2908 
2909     // Read a record.
2910     Record.clear();
2911     Instruction *I = nullptr;
2912     unsigned BitCode = Stream.readRecord(Entry.ID, Record);
2913     switch (BitCode) {
2914     default: // Default behavior: reject
2915       return Error("Invalid value");
2916     case bitc::FUNC_CODE_DECLAREBLOCKS: {   // DECLAREBLOCKS: [nblocks]
2917       if (Record.size() < 1 || Record[0] == 0)
2918         return Error("Invalid record");
2919       // Create all the basic blocks for the function.
2920       FunctionBBs.resize(Record[0]);
2921 
2922       // See if anything took the address of blocks in this function.
2923       auto BBFRI = BasicBlockFwdRefs.find(F);
2924       if (BBFRI == BasicBlockFwdRefs.end()) {
2925         for (unsigned i = 0, e = FunctionBBs.size(); i != e; ++i)
2926           FunctionBBs[i] = BasicBlock::Create(Context, "", F);
2927       } else {
2928         auto &BBRefs = BBFRI->second;
2929         // Check for invalid basic block references.
2930         if (BBRefs.size() > FunctionBBs.size())
2931           return Error("Invalid ID");
2932         assert(!BBRefs.empty() && "Unexpected empty array");
2933         assert(!BBRefs.front() && "Invalid reference to entry block");
2934         for (unsigned I = 0, E = FunctionBBs.size(), RE = BBRefs.size(); I != E;
2935              ++I)
2936           if (I < RE && BBRefs[I]) {
2937             BBRefs[I]->insertInto(F);
2938             FunctionBBs[I] = BBRefs[I];
2939           } else {
2940             FunctionBBs[I] = BasicBlock::Create(Context, "", F);
2941           }
2942 
2943         // Erase from the table.
2944         BasicBlockFwdRefs.erase(BBFRI);
2945       }
2946 
2947       CurBB = FunctionBBs[0];
2948       continue;
2949     }
2950 
2951     case bitc::FUNC_CODE_DEBUG_LOC_AGAIN:  // DEBUG_LOC_AGAIN
2952       // This record indicates that the last instruction is at the same
2953       // location as the previous instruction with a location.
2954       I = getLastInstruction();
2955 
2956       if (!I)
2957         return Error("Invalid record");
2958       I->setDebugLoc(LastLoc);
2959       I = nullptr;
2960       continue;
2961 
2962     case bitc::FUNC_CODE_DEBUG_LOC: {      // DEBUG_LOC: [line, col, scope, ia]
2963       I = getLastInstruction();
2964       if (!I || Record.size() < 4)
2965         return Error("Invalid record");
2966 
2967       unsigned Line = Record[0], Col = Record[1];
2968       unsigned ScopeID = Record[2], IAID = Record[3];
2969 
2970       MDNode *Scope = nullptr, *IA = nullptr;
2971       if (ScopeID) Scope = cast<MDNode>(MDValueList.getValueFwdRef(ScopeID-1));
2972       if (IAID)    IA = cast<MDNode>(MDValueList.getValueFwdRef(IAID-1));
2973       LastLoc = DebugLoc::get(Line, Col, Scope, IA);
2974       I->setDebugLoc(LastLoc);
2975       I = nullptr;
2976       continue;
2977     }
2978 
2979     case bitc::FUNC_CODE_INST_BINOP: {    // BINOP: [opval, ty, opval, opcode]
2980       unsigned OpNum = 0;
2981       Value *LHS, *RHS;
2982       if (getValueTypePair(Record, OpNum, NextValueNo, LHS) ||
2983           popValue(Record, OpNum, NextValueNo, LHS->getType(), RHS) ||
2984           OpNum+1 > Record.size())
2985         return Error("Invalid record");
2986 
2987       int Opc = GetDecodedBinaryOpcode(Record[OpNum++], LHS->getType());
2988       if (Opc == -1)
2989         return Error("Invalid record");
2990       I = BinaryOperator::Create((Instruction::BinaryOps)Opc, LHS, RHS);
2991       InstructionList.push_back(I);
2992       if (OpNum < Record.size()) {
2993         if (Opc == Instruction::Add ||
2994             Opc == Instruction::Sub ||
2995             Opc == Instruction::Mul ||
2996             Opc == Instruction::Shl) {
2997           if (Record[OpNum] & (1 << bitc::OBO_NO_SIGNED_WRAP))
2998             cast<BinaryOperator>(I)->setHasNoSignedWrap(true);
2999           if (Record[OpNum] & (1 << bitc::OBO_NO_UNSIGNED_WRAP))
3000             cast<BinaryOperator>(I)->setHasNoUnsignedWrap(true);
3001         } else if (Opc == Instruction::SDiv ||
3002                    Opc == Instruction::UDiv ||
3003                    Opc == Instruction::LShr ||
3004                    Opc == Instruction::AShr) {
3005           if (Record[OpNum] & (1 << bitc::PEO_EXACT))
3006             cast<BinaryOperator>(I)->setIsExact(true);
3007         } else if (isa<FPMathOperator>(I)) {
3008           FastMathFlags FMF;
3009           if (0 != (Record[OpNum] & FastMathFlags::UnsafeAlgebra))
3010             FMF.setUnsafeAlgebra();
3011           if (0 != (Record[OpNum] & FastMathFlags::NoNaNs))
3012             FMF.setNoNaNs();
3013           if (0 != (Record[OpNum] & FastMathFlags::NoInfs))
3014             FMF.setNoInfs();
3015           if (0 != (Record[OpNum] & FastMathFlags::NoSignedZeros))
3016             FMF.setNoSignedZeros();
3017           if (0 != (Record[OpNum] & FastMathFlags::AllowReciprocal))
3018             FMF.setAllowReciprocal();
3019           if (FMF.any())
3020             I->setFastMathFlags(FMF);
3021         }
3022 
3023       }
3024       break;
3025     }
3026     case bitc::FUNC_CODE_INST_CAST: {    // CAST: [opval, opty, destty, castopc]
3027       unsigned OpNum = 0;
3028       Value *Op;
3029       if (getValueTypePair(Record, OpNum, NextValueNo, Op) ||
3030           OpNum+2 != Record.size())
3031         return Error("Invalid record");
3032 
3033       Type *ResTy = getTypeByID(Record[OpNum]);
3034       int Opc = GetDecodedCastOpcode(Record[OpNum+1]);
3035       if (Opc == -1 || !ResTy)
3036         return Error("Invalid record");
3037       Instruction *Temp = nullptr;
3038       if ((I = UpgradeBitCastInst(Opc, Op, ResTy, Temp))) {
3039         if (Temp) {
3040           InstructionList.push_back(Temp);
3041           CurBB->getInstList().push_back(Temp);
3042         }
3043       } else {
3044         I = CastInst::Create((Instruction::CastOps)Opc, Op, ResTy);
3045       }
3046       InstructionList.push_back(I);
3047       break;
3048     }
3049     case bitc::FUNC_CODE_INST_INBOUNDS_GEP:
3050     case bitc::FUNC_CODE_INST_GEP: { // GEP: [n x operands]
3051       unsigned OpNum = 0;
3052       Value *BasePtr;
3053       if (getValueTypePair(Record, OpNum, NextValueNo, BasePtr))
3054         return Error("Invalid record");
3055 
3056       SmallVector<Value*, 16> GEPIdx;
3057       while (OpNum != Record.size()) {
3058         Value *Op;
3059         if (getValueTypePair(Record, OpNum, NextValueNo, Op))
3060           return Error("Invalid record");
3061         GEPIdx.push_back(Op);
3062       }
3063 
3064       I = GetElementPtrInst::Create(BasePtr, GEPIdx);
3065       InstructionList.push_back(I);
3066       if (BitCode == bitc::FUNC_CODE_INST_INBOUNDS_GEP)
3067         cast<GetElementPtrInst>(I)->setIsInBounds(true);
3068       break;
3069     }
3070 
3071     case bitc::FUNC_CODE_INST_EXTRACTVAL: {
3072                                        // EXTRACTVAL: [opty, opval, n x indices]
3073       unsigned OpNum = 0;
3074       Value *Agg;
3075       if (getValueTypePair(Record, OpNum, NextValueNo, Agg))
3076         return Error("Invalid record");
3077 
3078       SmallVector<unsigned, 4> EXTRACTVALIdx;
3079       Type *CurTy = Agg->getType();
3080       for (unsigned RecSize = Record.size();
3081            OpNum != RecSize; ++OpNum) {
3082         bool IsArray = CurTy->isArrayTy();
3083         bool IsStruct = CurTy->isStructTy();
3084         uint64_t Index = Record[OpNum];
3085 
3086         if (!IsStruct && !IsArray)
3087           return Error("EXTRACTVAL: Invalid type");
3088         if ((unsigned)Index != Index)
3089           return Error("Invalid value");
3090         if (IsStruct && Index >= CurTy->subtypes().size())
3091           return Error("EXTRACTVAL: Invalid struct index");
3092         if (IsArray && Index >= CurTy->getArrayNumElements())
3093           return Error("EXTRACTVAL: Invalid array index");
3094         EXTRACTVALIdx.push_back((unsigned)Index);
3095 
3096         if (IsStruct)
3097           CurTy = CurTy->subtypes()[Index];
3098         else
3099           CurTy = CurTy->subtypes()[0];
3100       }
3101 
3102       I = ExtractValueInst::Create(Agg, EXTRACTVALIdx);
3103       InstructionList.push_back(I);
3104       break;
3105     }
3106 
3107     case bitc::FUNC_CODE_INST_INSERTVAL: {
3108                            // INSERTVAL: [opty, opval, opty, opval, n x indices]
3109       unsigned OpNum = 0;
3110       Value *Agg;
3111       if (getValueTypePair(Record, OpNum, NextValueNo, Agg))
3112         return Error("Invalid record");
3113       Value *Val;
3114       if (getValueTypePair(Record, OpNum, NextValueNo, Val))
3115         return Error("Invalid record");
3116 
3117       SmallVector<unsigned, 4> INSERTVALIdx;
3118       Type *CurTy = Agg->getType();
3119       for (unsigned RecSize = Record.size();
3120            OpNum != RecSize; ++OpNum) {
3121         bool IsArray = CurTy->isArrayTy();
3122         bool IsStruct = CurTy->isStructTy();
3123         uint64_t Index = Record[OpNum];
3124 
3125         if (!IsStruct && !IsArray)
3126           return Error("INSERTVAL: Invalid type");
3127         if (!CurTy->isStructTy() && !CurTy->isArrayTy())
3128           return Error("Invalid type");
3129         if ((unsigned)Index != Index)
3130           return Error("Invalid value");
3131         if (IsStruct && Index >= CurTy->subtypes().size())
3132           return Error("INSERTVAL: Invalid struct index");
3133         if (IsArray && Index >= CurTy->getArrayNumElements())
3134           return Error("INSERTVAL: Invalid array index");
3135 
3136         INSERTVALIdx.push_back((unsigned)Index);
3137         if (IsStruct)
3138           CurTy = CurTy->subtypes()[Index];
3139         else
3140           CurTy = CurTy->subtypes()[0];
3141       }
3142 
3143       I = InsertValueInst::Create(Agg, Val, INSERTVALIdx);
3144       InstructionList.push_back(I);
3145       break;
3146     }
3147 
3148     case bitc::FUNC_CODE_INST_SELECT: { // SELECT: [opval, ty, opval, opval]
3149       // obsolete form of select
3150       // handles select i1 ... in old bitcode
3151       unsigned OpNum = 0;
3152       Value *TrueVal, *FalseVal, *Cond;
3153       if (getValueTypePair(Record, OpNum, NextValueNo, TrueVal) ||
3154           popValue(Record, OpNum, NextValueNo, TrueVal->getType(), FalseVal) ||
3155           popValue(Record, OpNum, NextValueNo, Type::getInt1Ty(Context), Cond))
3156         return Error("Invalid record");
3157 
3158       I = SelectInst::Create(Cond, TrueVal, FalseVal);
3159       InstructionList.push_back(I);
3160       break;
3161     }
3162 
3163     case bitc::FUNC_CODE_INST_VSELECT: {// VSELECT: [ty,opval,opval,predty,pred]
3164       // new form of select
3165       // handles select i1 or select [N x i1]
3166       unsigned OpNum = 0;
3167       Value *TrueVal, *FalseVal, *Cond;
3168       if (getValueTypePair(Record, OpNum, NextValueNo, TrueVal) ||
3169           popValue(Record, OpNum, NextValueNo, TrueVal->getType(), FalseVal) ||
3170           getValueTypePair(Record, OpNum, NextValueNo, Cond))
3171         return Error("Invalid record");
3172 
3173       // select condition can be either i1 or [N x i1]
3174       if (VectorType* vector_type =
3175           dyn_cast<VectorType>(Cond->getType())) {
3176         // expect <n x i1>
3177         if (vector_type->getElementType() != Type::getInt1Ty(Context))
3178           return Error("Invalid type for value");
3179       } else {
3180         // expect i1
3181         if (Cond->getType() != Type::getInt1Ty(Context))
3182           return Error("Invalid type for value");
3183       }
3184 
3185       I = SelectInst::Create(Cond, TrueVal, FalseVal);
3186       InstructionList.push_back(I);
3187       break;
3188     }
3189 
3190     case bitc::FUNC_CODE_INST_EXTRACTELT: { // EXTRACTELT: [opty, opval, opval]
3191       unsigned OpNum = 0;
3192       Value *Vec, *Idx;
3193       if (getValueTypePair(Record, OpNum, NextValueNo, Vec) ||
3194           getValueTypePair(Record, OpNum, NextValueNo, Idx))
3195         return Error("Invalid record");
3196       I = ExtractElementInst::Create(Vec, Idx);
3197       InstructionList.push_back(I);
3198       break;
3199     }
3200 
3201     case bitc::FUNC_CODE_INST_INSERTELT: { // INSERTELT: [ty, opval,opval,opval]
3202       unsigned OpNum = 0;
3203       Value *Vec, *Elt, *Idx;
3204       if (getValueTypePair(Record, OpNum, NextValueNo, Vec) ||
3205           popValue(Record, OpNum, NextValueNo,
3206                    cast<VectorType>(Vec->getType())->getElementType(), Elt) ||
3207           getValueTypePair(Record, OpNum, NextValueNo, Idx))
3208         return Error("Invalid record");
3209       I = InsertElementInst::Create(Vec, Elt, Idx);
3210       InstructionList.push_back(I);
3211       break;
3212     }
3213 
3214     case bitc::FUNC_CODE_INST_SHUFFLEVEC: {// SHUFFLEVEC: [opval,ty,opval,opval]
3215       unsigned OpNum = 0;
3216       Value *Vec1, *Vec2, *Mask;
3217       if (getValueTypePair(Record, OpNum, NextValueNo, Vec1) ||
3218           popValue(Record, OpNum, NextValueNo, Vec1->getType(), Vec2))
3219         return Error("Invalid record");
3220 
3221       if (getValueTypePair(Record, OpNum, NextValueNo, Mask))
3222         return Error("Invalid record");
3223       I = new ShuffleVectorInst(Vec1, Vec2, Mask);
3224       InstructionList.push_back(I);
3225       break;
3226     }
3227 
3228     case bitc::FUNC_CODE_INST_CMP:   // CMP: [opty, opval, opval, pred]
3229       // Old form of ICmp/FCmp returning bool
3230       // Existed to differentiate between icmp/fcmp and vicmp/vfcmp which were
3231       // both legal on vectors but had different behaviour.
3232     case bitc::FUNC_CODE_INST_CMP2: { // CMP2: [opty, opval, opval, pred]
3233       // FCmp/ICmp returning bool or vector of bool
3234 
3235       unsigned OpNum = 0;
3236       Value *LHS, *RHS;
3237       if (getValueTypePair(Record, OpNum, NextValueNo, LHS) ||
3238           popValue(Record, OpNum, NextValueNo, LHS->getType(), RHS) ||
3239           OpNum+1 != Record.size())
3240         return Error("Invalid record");
3241 
3242       if (LHS->getType()->isFPOrFPVectorTy())
3243         I = new FCmpInst((FCmpInst::Predicate)Record[OpNum], LHS, RHS);
3244       else
3245         I = new ICmpInst((ICmpInst::Predicate)Record[OpNum], LHS, RHS);
3246       InstructionList.push_back(I);
3247       break;
3248     }
3249 
3250     case bitc::FUNC_CODE_INST_RET: // RET: [opty,opval<optional>]
3251       {
3252         unsigned Size = Record.size();
3253         if (Size == 0) {
3254           I = ReturnInst::Create(Context);
3255           InstructionList.push_back(I);
3256           break;
3257         }
3258 
3259         unsigned OpNum = 0;
3260         Value *Op = nullptr;
3261         if (getValueTypePair(Record, OpNum, NextValueNo, Op))
3262           return Error("Invalid record");
3263         if (OpNum != Record.size())
3264           return Error("Invalid record");
3265 
3266         I = ReturnInst::Create(Context, Op);
3267         InstructionList.push_back(I);
3268         break;
3269       }
3270     case bitc::FUNC_CODE_INST_BR: { // BR: [bb#, bb#, opval] or [bb#]
3271       if (Record.size() != 1 && Record.size() != 3)
3272         return Error("Invalid record");
3273       BasicBlock *TrueDest = getBasicBlock(Record[0]);
3274       if (!TrueDest)
3275         return Error("Invalid record");
3276 
3277       if (Record.size() == 1) {
3278         I = BranchInst::Create(TrueDest);
3279         InstructionList.push_back(I);
3280       }
3281       else {
3282         BasicBlock *FalseDest = getBasicBlock(Record[1]);
3283         Value *Cond = getValue(Record, 2, NextValueNo,
3284                                Type::getInt1Ty(Context));
3285         if (!FalseDest || !Cond)
3286           return Error("Invalid record");
3287         I = BranchInst::Create(TrueDest, FalseDest, Cond);
3288         InstructionList.push_back(I);
3289       }
3290       break;
3291     }
3292     case bitc::FUNC_CODE_INST_SWITCH: { // SWITCH: [opty, op0, op1, ...]
3293       // Check magic
3294       if ((Record[0] >> 16) == SWITCH_INST_MAGIC) {
3295         // "New" SwitchInst format with case ranges. The changes to write this
3296         // format were reverted but we still recognize bitcode that uses it.
3297         // Hopefully someday we will have support for case ranges and can use
3298         // this format again.
3299 
3300         Type *OpTy = getTypeByID(Record[1]);
3301         unsigned ValueBitWidth = cast<IntegerType>(OpTy)->getBitWidth();
3302 
3303         Value *Cond = getValue(Record, 2, NextValueNo, OpTy);
3304         BasicBlock *Default = getBasicBlock(Record[3]);
3305         if (!OpTy || !Cond || !Default)
3306           return Error("Invalid record");
3307 
3308         unsigned NumCases = Record[4];
3309 
3310         SwitchInst *SI = SwitchInst::Create(Cond, Default, NumCases);
3311         InstructionList.push_back(SI);
3312 
3313         unsigned CurIdx = 5;
3314         for (unsigned i = 0; i != NumCases; ++i) {
3315           SmallVector<ConstantInt*, 1> CaseVals;
3316           unsigned NumItems = Record[CurIdx++];
3317           for (unsigned ci = 0; ci != NumItems; ++ci) {
3318             bool isSingleNumber = Record[CurIdx++];
3319 
3320             APInt Low;
3321             unsigned ActiveWords = 1;
3322             if (ValueBitWidth > 64)
3323               ActiveWords = Record[CurIdx++];
3324             Low = ReadWideAPInt(makeArrayRef(&Record[CurIdx], ActiveWords),
3325                                 ValueBitWidth);
3326             CurIdx += ActiveWords;
3327 
3328             if (!isSingleNumber) {
3329               ActiveWords = 1;
3330               if (ValueBitWidth > 64)
3331                 ActiveWords = Record[CurIdx++];
3332               APInt High =
3333                   ReadWideAPInt(makeArrayRef(&Record[CurIdx], ActiveWords),
3334                                 ValueBitWidth);
3335               CurIdx += ActiveWords;
3336 
3337               // FIXME: It is not clear whether values in the range should be
3338               // compared as signed or unsigned values. The partially
3339               // implemented changes that used this format in the past used
3340               // unsigned comparisons.
3341               for ( ; Low.ule(High); ++Low)
3342                 CaseVals.push_back(ConstantInt::get(Context, Low));
3343             } else
3344               CaseVals.push_back(ConstantInt::get(Context, Low));
3345           }
3346           BasicBlock *DestBB = getBasicBlock(Record[CurIdx++]);
3347           for (SmallVector<ConstantInt*, 1>::iterator cvi = CaseVals.begin(),
3348                  cve = CaseVals.end(); cvi != cve; ++cvi)
3349             SI->addCase(*cvi, DestBB);
3350         }
3351         I = SI;
3352         break;
3353       }
3354 
3355       // Old SwitchInst format without case ranges.
3356 
3357       if (Record.size() < 3 || (Record.size() & 1) == 0)
3358         return Error("Invalid record");
3359       Type *OpTy = getTypeByID(Record[0]);
3360       Value *Cond = getValue(Record, 1, NextValueNo, OpTy);
3361       BasicBlock *Default = getBasicBlock(Record[2]);
3362       if (!OpTy || !Cond || !Default)
3363         return Error("Invalid record");
3364       unsigned NumCases = (Record.size()-3)/2;
3365       SwitchInst *SI = SwitchInst::Create(Cond, Default, NumCases);
3366       InstructionList.push_back(SI);
3367       for (unsigned i = 0, e = NumCases; i != e; ++i) {
3368         ConstantInt *CaseVal =
3369           dyn_cast_or_null<ConstantInt>(getFnValueByID(Record[3+i*2], OpTy));
3370         BasicBlock *DestBB = getBasicBlock(Record[1+3+i*2]);
3371         if (!CaseVal || !DestBB) {
3372           delete SI;
3373           return Error("Invalid record");
3374         }
3375         SI->addCase(CaseVal, DestBB);
3376       }
3377       I = SI;
3378       break;
3379     }
3380     case bitc::FUNC_CODE_INST_INDIRECTBR: { // INDIRECTBR: [opty, op0, op1, ...]
3381       if (Record.size() < 2)
3382         return Error("Invalid record");
3383       Type *OpTy = getTypeByID(Record[0]);
3384       Value *Address = getValue(Record, 1, NextValueNo, OpTy);
3385       if (!OpTy || !Address)
3386         return Error("Invalid record");
3387       unsigned NumDests = Record.size()-2;
3388       IndirectBrInst *IBI = IndirectBrInst::Create(Address, NumDests);
3389       InstructionList.push_back(IBI);
3390       for (unsigned i = 0, e = NumDests; i != e; ++i) {
3391         if (BasicBlock *DestBB = getBasicBlock(Record[2+i])) {
3392           IBI->addDestination(DestBB);
3393         } else {
3394           delete IBI;
3395           return Error("Invalid record");
3396         }
3397       }
3398       I = IBI;
3399       break;
3400     }
3401 
3402     case bitc::FUNC_CODE_INST_INVOKE: {
3403       // INVOKE: [attrs, cc, normBB, unwindBB, fnty, op0,op1,op2, ...]
3404       if (Record.size() < 4)
3405         return Error("Invalid record");
3406       AttributeSet PAL = getAttributes(Record[0]);
3407       unsigned CCInfo = Record[1];
3408       BasicBlock *NormalBB = getBasicBlock(Record[2]);
3409       BasicBlock *UnwindBB = getBasicBlock(Record[3]);
3410 
3411       unsigned OpNum = 4;
3412       Value *Callee;
3413       if (getValueTypePair(Record, OpNum, NextValueNo, Callee))
3414         return Error("Invalid record");
3415 
3416       PointerType *CalleeTy = dyn_cast<PointerType>(Callee->getType());
3417       FunctionType *FTy = !CalleeTy ? nullptr :
3418         dyn_cast<FunctionType>(CalleeTy->getElementType());
3419 
3420       // Check that the right number of fixed parameters are here.
3421       if (!FTy || !NormalBB || !UnwindBB ||
3422           Record.size() < OpNum+FTy->getNumParams())
3423         return Error("Invalid record");
3424 
3425       SmallVector<Value*, 16> Ops;
3426       for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i, ++OpNum) {
3427         Ops.push_back(getValue(Record, OpNum, NextValueNo,
3428                                FTy->getParamType(i)));
3429         if (!Ops.back())
3430           return Error("Invalid record");
3431       }
3432 
3433       if (!FTy->isVarArg()) {
3434         if (Record.size() != OpNum)
3435           return Error("Invalid record");
3436       } else {
3437         // Read type/value pairs for varargs params.
3438         while (OpNum != Record.size()) {
3439           Value *Op;
3440           if (getValueTypePair(Record, OpNum, NextValueNo, Op))
3441             return Error("Invalid record");
3442           Ops.push_back(Op);
3443         }
3444       }
3445 
3446       I = InvokeInst::Create(Callee, NormalBB, UnwindBB, Ops);
3447       InstructionList.push_back(I);
3448       cast<InvokeInst>(I)->setCallingConv(
3449         static_cast<CallingConv::ID>(CCInfo));
3450       cast<InvokeInst>(I)->setAttributes(PAL);
3451       break;
3452     }
3453     case bitc::FUNC_CODE_INST_RESUME: { // RESUME: [opval]
3454       unsigned Idx = 0;
3455       Value *Val = nullptr;
3456       if (getValueTypePair(Record, Idx, NextValueNo, Val))
3457         return Error("Invalid record");
3458       I = ResumeInst::Create(Val);
3459       InstructionList.push_back(I);
3460       break;
3461     }
3462     case bitc::FUNC_CODE_INST_UNREACHABLE: // UNREACHABLE
3463       I = new UnreachableInst(Context);
3464       InstructionList.push_back(I);
3465       break;
3466     case bitc::FUNC_CODE_INST_PHI: { // PHI: [ty, val0,bb0, ...]
3467       if (Record.size() < 1 || ((Record.size()-1)&1))
3468         return Error("Invalid record");
3469       Type *Ty = getTypeByID(Record[0]);
3470       if (!Ty)
3471         return Error("Invalid record");
3472 
3473       PHINode *PN = PHINode::Create(Ty, (Record.size()-1)/2);
3474       InstructionList.push_back(PN);
3475 
3476       for (unsigned i = 0, e = Record.size()-1; i != e; i += 2) {
3477         Value *V;
3478         // With the new function encoding, it is possible that operands have
3479         // negative IDs (for forward references).  Use a signed VBR
3480         // representation to keep the encoding small.
3481         if (UseRelativeIDs)
3482           V = getValueSigned(Record, 1+i, NextValueNo, Ty);
3483         else
3484           V = getValue(Record, 1+i, NextValueNo, Ty);
3485         BasicBlock *BB = getBasicBlock(Record[2+i]);
3486         if (!V || !BB)
3487           return Error("Invalid record");
3488         PN->addIncoming(V, BB);
3489       }
3490       I = PN;
3491       break;
3492     }
3493 
3494     case bitc::FUNC_CODE_INST_LANDINGPAD: {
3495       // LANDINGPAD: [ty, val, val, num, (id0,val0 ...)?]
3496       unsigned Idx = 0;
3497       if (Record.size() < 4)
3498         return Error("Invalid record");
3499       Type *Ty = getTypeByID(Record[Idx++]);
3500       if (!Ty)
3501         return Error("Invalid record");
3502       Value *PersFn = nullptr;
3503       if (getValueTypePair(Record, Idx, NextValueNo, PersFn))
3504         return Error("Invalid record");
3505 
3506       bool IsCleanup = !!Record[Idx++];
3507       unsigned NumClauses = Record[Idx++];
3508       LandingPadInst *LP = LandingPadInst::Create(Ty, PersFn, NumClauses);
3509       LP->setCleanup(IsCleanup);
3510       for (unsigned J = 0; J != NumClauses; ++J) {
3511         LandingPadInst::ClauseType CT =
3512           LandingPadInst::ClauseType(Record[Idx++]); (void)CT;
3513         Value *Val;
3514 
3515         if (getValueTypePair(Record, Idx, NextValueNo, Val)) {
3516           delete LP;
3517           return Error("Invalid record");
3518         }
3519 
3520         assert((CT != LandingPadInst::Catch ||
3521                 !isa<ArrayType>(Val->getType())) &&
3522                "Catch clause has a invalid type!");
3523         assert((CT != LandingPadInst::Filter ||
3524                 isa<ArrayType>(Val->getType())) &&
3525                "Filter clause has invalid type!");
3526         LP->addClause(cast<Constant>(Val));
3527       }
3528 
3529       I = LP;
3530       InstructionList.push_back(I);
3531       break;
3532     }
3533 
3534     case bitc::FUNC_CODE_INST_ALLOCA: { // ALLOCA: [instty, opty, op, align]
3535       if (Record.size() != 4)
3536         return Error("Invalid record");
3537       PointerType *Ty =
3538         dyn_cast_or_null<PointerType>(getTypeByID(Record[0]));
3539       Type *OpTy = getTypeByID(Record[1]);
3540       Value *Size = getFnValueByID(Record[2], OpTy);
3541       unsigned AlignRecord = Record[3];
3542       bool InAlloca = AlignRecord & (1 << 5);
3543       unsigned Align = AlignRecord & ((1 << 5) - 1);
3544       if (!Ty || !Size)
3545         return Error("Invalid record");
3546       AllocaInst *AI = new AllocaInst(Ty->getElementType(), Size, (1 << Align) >> 1);
3547       AI->setUsedWithInAlloca(InAlloca);
3548       I = AI;
3549       InstructionList.push_back(I);
3550       break;
3551     }
3552     case bitc::FUNC_CODE_INST_LOAD: { // LOAD: [opty, op, align, vol]
3553       unsigned OpNum = 0;
3554       Value *Op;
3555       if (getValueTypePair(Record, OpNum, NextValueNo, Op) ||
3556           OpNum+2 != Record.size())
3557         return Error("Invalid record");
3558 
3559       I = new LoadInst(Op, "", Record[OpNum+1], (1 << Record[OpNum]) >> 1);
3560       InstructionList.push_back(I);
3561       break;
3562     }
3563     case bitc::FUNC_CODE_INST_LOADATOMIC: {
3564        // LOADATOMIC: [opty, op, align, vol, ordering, synchscope]
3565       unsigned OpNum = 0;
3566       Value *Op;
3567       if (getValueTypePair(Record, OpNum, NextValueNo, Op) ||
3568           OpNum+4 != Record.size())
3569         return Error("Invalid record");
3570 
3571       AtomicOrdering Ordering = GetDecodedOrdering(Record[OpNum+2]);
3572       if (Ordering == NotAtomic || Ordering == Release ||
3573           Ordering == AcquireRelease)
3574         return Error("Invalid record");
3575       if (Ordering != NotAtomic && Record[OpNum] == 0)
3576         return Error("Invalid record");
3577       SynchronizationScope SynchScope = GetDecodedSynchScope(Record[OpNum+3]);
3578 
3579       I = new LoadInst(Op, "", Record[OpNum+1], (1 << Record[OpNum]) >> 1,
3580                        Ordering, SynchScope);
3581       InstructionList.push_back(I);
3582       break;
3583     }
3584     case bitc::FUNC_CODE_INST_STORE: { // STORE2:[ptrty, ptr, val, align, vol]
3585       unsigned OpNum = 0;
3586       Value *Val, *Ptr;
3587       if (getValueTypePair(Record, OpNum, NextValueNo, Ptr) ||
3588           popValue(Record, OpNum, NextValueNo,
3589                     cast<PointerType>(Ptr->getType())->getElementType(), Val) ||
3590           OpNum+2 != Record.size())
3591         return Error("Invalid record");
3592 
3593       I = new StoreInst(Val, Ptr, Record[OpNum+1], (1 << Record[OpNum]) >> 1);
3594       InstructionList.push_back(I);
3595       break;
3596     }
3597     case bitc::FUNC_CODE_INST_STOREATOMIC: {
3598       // STOREATOMIC: [ptrty, ptr, val, align, vol, ordering, synchscope]
3599       unsigned OpNum = 0;
3600       Value *Val, *Ptr;
3601       if (getValueTypePair(Record, OpNum, NextValueNo, Ptr) ||
3602           popValue(Record, OpNum, NextValueNo,
3603                     cast<PointerType>(Ptr->getType())->getElementType(), Val) ||
3604           OpNum+4 != Record.size())
3605         return Error("Invalid record");
3606 
3607       AtomicOrdering Ordering = GetDecodedOrdering(Record[OpNum+2]);
3608       if (Ordering == NotAtomic || Ordering == Acquire ||
3609           Ordering == AcquireRelease)
3610         return Error("Invalid record");
3611       SynchronizationScope SynchScope = GetDecodedSynchScope(Record[OpNum+3]);
3612       if (Ordering != NotAtomic && Record[OpNum] == 0)
3613         return Error("Invalid record");
3614 
3615       I = new StoreInst(Val, Ptr, Record[OpNum+1], (1 << Record[OpNum]) >> 1,
3616                         Ordering, SynchScope);
3617       InstructionList.push_back(I);
3618       break;
3619     }
3620     case bitc::FUNC_CODE_INST_CMPXCHG: {
3621       // CMPXCHG:[ptrty, ptr, cmp, new, vol, successordering, synchscope,
3622       //          failureordering?, isweak?]
3623       unsigned OpNum = 0;
3624       Value *Ptr, *Cmp, *New;
3625       if (getValueTypePair(Record, OpNum, NextValueNo, Ptr) ||
3626           popValue(Record, OpNum, NextValueNo,
3627                     cast<PointerType>(Ptr->getType())->getElementType(), Cmp) ||
3628           popValue(Record, OpNum, NextValueNo,
3629                     cast<PointerType>(Ptr->getType())->getElementType(), New) ||
3630           (Record.size() < OpNum + 3 || Record.size() > OpNum + 5))
3631         return Error("Invalid record");
3632       AtomicOrdering SuccessOrdering = GetDecodedOrdering(Record[OpNum+1]);
3633       if (SuccessOrdering == NotAtomic || SuccessOrdering == Unordered)
3634         return Error("Invalid record");
3635       SynchronizationScope SynchScope = GetDecodedSynchScope(Record[OpNum+2]);
3636 
3637       AtomicOrdering FailureOrdering;
3638       if (Record.size() < 7)
3639         FailureOrdering =
3640             AtomicCmpXchgInst::getStrongestFailureOrdering(SuccessOrdering);
3641       else
3642         FailureOrdering = GetDecodedOrdering(Record[OpNum+3]);
3643 
3644       I = new AtomicCmpXchgInst(Ptr, Cmp, New, SuccessOrdering, FailureOrdering,
3645                                 SynchScope);
3646       cast<AtomicCmpXchgInst>(I)->setVolatile(Record[OpNum]);
3647 
3648       if (Record.size() < 8) {
3649         // Before weak cmpxchgs existed, the instruction simply returned the
3650         // value loaded from memory, so bitcode files from that era will be
3651         // expecting the first component of a modern cmpxchg.
3652         CurBB->getInstList().push_back(I);
3653         I = ExtractValueInst::Create(I, 0);
3654       } else {
3655         cast<AtomicCmpXchgInst>(I)->setWeak(Record[OpNum+4]);
3656       }
3657 
3658       InstructionList.push_back(I);
3659       break;
3660     }
3661     case bitc::FUNC_CODE_INST_ATOMICRMW: {
3662       // ATOMICRMW:[ptrty, ptr, val, op, vol, ordering, synchscope]
3663       unsigned OpNum = 0;
3664       Value *Ptr, *Val;
3665       if (getValueTypePair(Record, OpNum, NextValueNo, Ptr) ||
3666           popValue(Record, OpNum, NextValueNo,
3667                     cast<PointerType>(Ptr->getType())->getElementType(), Val) ||
3668           OpNum+4 != Record.size())
3669         return Error("Invalid record");
3670       AtomicRMWInst::BinOp Operation = GetDecodedRMWOperation(Record[OpNum]);
3671       if (Operation < AtomicRMWInst::FIRST_BINOP ||
3672           Operation > AtomicRMWInst::LAST_BINOP)
3673         return Error("Invalid record");
3674       AtomicOrdering Ordering = GetDecodedOrdering(Record[OpNum+2]);
3675       if (Ordering == NotAtomic || Ordering == Unordered)
3676         return Error("Invalid record");
3677       SynchronizationScope SynchScope = GetDecodedSynchScope(Record[OpNum+3]);
3678       I = new AtomicRMWInst(Operation, Ptr, Val, Ordering, SynchScope);
3679       cast<AtomicRMWInst>(I)->setVolatile(Record[OpNum+1]);
3680       InstructionList.push_back(I);
3681       break;
3682     }
3683     case bitc::FUNC_CODE_INST_FENCE: { // FENCE:[ordering, synchscope]
3684       if (2 != Record.size())
3685         return Error("Invalid record");
3686       AtomicOrdering Ordering = GetDecodedOrdering(Record[0]);
3687       if (Ordering == NotAtomic || Ordering == Unordered ||
3688           Ordering == Monotonic)
3689         return Error("Invalid record");
3690       SynchronizationScope SynchScope = GetDecodedSynchScope(Record[1]);
3691       I = new FenceInst(Context, Ordering, SynchScope);
3692       InstructionList.push_back(I);
3693       break;
3694     }
3695     case bitc::FUNC_CODE_INST_CALL: {
3696       // CALL: [paramattrs, cc, fnty, fnid, arg0, arg1...]
3697       if (Record.size() < 3)
3698         return Error("Invalid record");
3699 
3700       AttributeSet PAL = getAttributes(Record[0]);
3701       unsigned CCInfo = Record[1];
3702 
3703       unsigned OpNum = 2;
3704       Value *Callee;
3705       if (getValueTypePair(Record, OpNum, NextValueNo, Callee))
3706         return Error("Invalid record");
3707 
3708       PointerType *OpTy = dyn_cast<PointerType>(Callee->getType());
3709       FunctionType *FTy = nullptr;
3710       if (OpTy) FTy = dyn_cast<FunctionType>(OpTy->getElementType());
3711       if (!FTy || Record.size() < FTy->getNumParams()+OpNum)
3712         return Error("Invalid record");
3713 
3714       SmallVector<Value*, 16> Args;
3715       // Read the fixed params.
3716       for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i, ++OpNum) {
3717         if (FTy->getParamType(i)->isLabelTy())
3718           Args.push_back(getBasicBlock(Record[OpNum]));
3719         else
3720           Args.push_back(getValue(Record, OpNum, NextValueNo,
3721                                   FTy->getParamType(i)));
3722         if (!Args.back())
3723           return Error("Invalid record");
3724       }
3725 
3726       // Read type/value pairs for varargs params.
3727       if (!FTy->isVarArg()) {
3728         if (OpNum != Record.size())
3729           return Error("Invalid record");
3730       } else {
3731         while (OpNum != Record.size()) {
3732           Value *Op;
3733           if (getValueTypePair(Record, OpNum, NextValueNo, Op))
3734             return Error("Invalid record");
3735           Args.push_back(Op);
3736         }
3737       }
3738 
3739       I = CallInst::Create(Callee, Args);
3740       InstructionList.push_back(I);
3741       cast<CallInst>(I)->setCallingConv(
3742           static_cast<CallingConv::ID>((~(1U << 14) & CCInfo) >> 1));
3743       CallInst::TailCallKind TCK = CallInst::TCK_None;
3744       if (CCInfo & 1)
3745         TCK = CallInst::TCK_Tail;
3746       if (CCInfo & (1 << 14))
3747         TCK = CallInst::TCK_MustTail;
3748       cast<CallInst>(I)->setTailCallKind(TCK);
3749       cast<CallInst>(I)->setAttributes(PAL);
3750       break;
3751     }
3752     case bitc::FUNC_CODE_INST_VAARG: { // VAARG: [valistty, valist, instty]
3753       if (Record.size() < 3)
3754         return Error("Invalid record");
3755       Type *OpTy = getTypeByID(Record[0]);
3756       Value *Op = getValue(Record, 1, NextValueNo, OpTy);
3757       Type *ResTy = getTypeByID(Record[2]);
3758       if (!OpTy || !Op || !ResTy)
3759         return Error("Invalid record");
3760       I = new VAArgInst(Op, ResTy);
3761       InstructionList.push_back(I);
3762       break;
3763     }
3764     }
3765 
3766     // Add instruction to end of current BB.  If there is no current BB, reject
3767     // this file.
3768     if (!CurBB) {
3769       delete I;
3770       return Error("Invalid instruction with no BB");
3771     }
3772     CurBB->getInstList().push_back(I);
3773 
3774     // If this was a terminator instruction, move to the next block.
3775     if (isa<TerminatorInst>(I)) {
3776       ++CurBBNo;
3777       CurBB = CurBBNo < FunctionBBs.size() ? FunctionBBs[CurBBNo] : nullptr;
3778     }
3779 
3780     // Non-void values get registered in the value table for future use.
3781     if (I && !I->getType()->isVoidTy())
3782       ValueList.AssignValue(I, NextValueNo++);
3783   }
3784 
3785 OutOfRecordLoop:
3786 
3787   // Check the function list for unresolved values.
3788   if (Argument *A = dyn_cast<Argument>(ValueList.back())) {
3789     if (!A->getParent()) {
3790       // We found at least one unresolved value.  Nuke them all to avoid leaks.
3791       for (unsigned i = ModuleValueListSize, e = ValueList.size(); i != e; ++i){
3792         if ((A = dyn_cast_or_null<Argument>(ValueList[i])) && !A->getParent()) {
3793           A->replaceAllUsesWith(UndefValue::get(A->getType()));
3794           delete A;
3795         }
3796       }
3797       return Error("Never resolved value found in function");
3798     }
3799   }
3800 
3801   // FIXME: Check for unresolved forward-declared metadata references
3802   // and clean up leaks.
3803 
3804   // Trim the value list down to the size it was before we parsed this function.
3805   ValueList.shrinkTo(ModuleValueListSize);
3806   MDValueList.shrinkTo(ModuleMDValueListSize);
3807   std::vector<BasicBlock*>().swap(FunctionBBs);
3808   return std::error_code();
3809 }
3810 
3811 /// Find the function body in the bitcode stream
3812 std::error_code BitcodeReader::FindFunctionInStream(
3813     Function *F,
3814     DenseMap<Function *, uint64_t>::iterator DeferredFunctionInfoIterator) {
3815   while (DeferredFunctionInfoIterator->second == 0) {
3816     if (Stream.AtEndOfStream())
3817       return Error("Could not find function in stream");
3818     // ParseModule will parse the next body in the stream and set its
3819     // position in the DeferredFunctionInfo map.
3820     if (std::error_code EC = ParseModule(true))
3821       return EC;
3822   }
3823   return std::error_code();
3824 }
3825 
3826 //===----------------------------------------------------------------------===//
3827 // GVMaterializer implementation
3828 //===----------------------------------------------------------------------===//
3829 
3830 void BitcodeReader::releaseBuffer() { Buffer.release(); }
3831 
3832 std::error_code BitcodeReader::materialize(GlobalValue *GV) {
3833   Function *F = dyn_cast<Function>(GV);
3834   // If it's not a function or is already material, ignore the request.
3835   if (!F || !F->isMaterializable())
3836     return std::error_code();
3837 
3838   DenseMap<Function*, uint64_t>::iterator DFII = DeferredFunctionInfo.find(F);
3839   assert(DFII != DeferredFunctionInfo.end() && "Deferred function not found!");
3840   // If its position is recorded as 0, its body is somewhere in the stream
3841   // but we haven't seen it yet.
3842   if (DFII->second == 0 && LazyStreamer)
3843     if (std::error_code EC = FindFunctionInStream(F, DFII))
3844       return EC;
3845 
3846   // Move the bit stream to the saved position of the deferred function body.
3847   Stream.JumpToBit(DFII->second);
3848 
3849   if (std::error_code EC = ParseFunctionBody(F))
3850     return EC;
3851   F->setIsMaterializable(false);
3852 
3853   // Upgrade any old intrinsic calls in the function.
3854   for (UpgradedIntrinsicMap::iterator I = UpgradedIntrinsics.begin(),
3855        E = UpgradedIntrinsics.end(); I != E; ++I) {
3856     if (I->first != I->second) {
3857       for (auto UI = I->first->user_begin(), UE = I->first->user_end();
3858            UI != UE;) {
3859         if (CallInst* CI = dyn_cast<CallInst>(*UI++))
3860           UpgradeIntrinsicCall(CI, I->second);
3861       }
3862     }
3863   }
3864 
3865   // Bring in any functions that this function forward-referenced via
3866   // blockaddresses.
3867   return materializeForwardReferencedFunctions();
3868 }
3869 
3870 bool BitcodeReader::isDematerializable(const GlobalValue *GV) const {
3871   const Function *F = dyn_cast<Function>(GV);
3872   if (!F || F->isDeclaration())
3873     return false;
3874 
3875   // Dematerializing F would leave dangling references that wouldn't be
3876   // reconnected on re-materialization.
3877   if (BlockAddressesTaken.count(F))
3878     return false;
3879 
3880   return DeferredFunctionInfo.count(const_cast<Function*>(F));
3881 }
3882 
3883 void BitcodeReader::Dematerialize(GlobalValue *GV) {
3884   Function *F = dyn_cast<Function>(GV);
3885   // If this function isn't dematerializable, this is a noop.
3886   if (!F || !isDematerializable(F))
3887     return;
3888 
3889   assert(DeferredFunctionInfo.count(F) && "No info to read function later?");
3890 
3891   // Just forget the function body, we can remat it later.
3892   F->dropAllReferences();
3893   F->setIsMaterializable(true);
3894 }
3895 
3896 std::error_code BitcodeReader::MaterializeModule(Module *M) {
3897   assert(M == TheModule &&
3898          "Can only Materialize the Module this BitcodeReader is attached to.");
3899 
3900   // Promise to materialize all forward references.
3901   WillMaterializeAllForwardRefs = true;
3902 
3903   // Iterate over the module, deserializing any functions that are still on
3904   // disk.
3905   for (Module::iterator F = TheModule->begin(), E = TheModule->end();
3906        F != E; ++F) {
3907     if (std::error_code EC = materialize(F))
3908       return EC;
3909   }
3910   // At this point, if there are any function bodies, the current bit is
3911   // pointing to the END_BLOCK record after them. Now make sure the rest
3912   // of the bits in the module have been read.
3913   if (NextUnreadBit)
3914     ParseModule(true);
3915 
3916   // Check that all block address forward references got resolved (as we
3917   // promised above).
3918   if (!BasicBlockFwdRefs.empty())
3919     return Error("Never resolved function from blockaddress");
3920 
3921   // Upgrade any intrinsic calls that slipped through (should not happen!) and
3922   // delete the old functions to clean up. We can't do this unless the entire
3923   // module is materialized because there could always be another function body
3924   // with calls to the old function.
3925   for (std::vector<std::pair<Function*, Function*> >::iterator I =
3926        UpgradedIntrinsics.begin(), E = UpgradedIntrinsics.end(); I != E; ++I) {
3927     if (I->first != I->second) {
3928       for (auto UI = I->first->user_begin(), UE = I->first->user_end();
3929            UI != UE;) {
3930         if (CallInst* CI = dyn_cast<CallInst>(*UI++))
3931           UpgradeIntrinsicCall(CI, I->second);
3932       }
3933       if (!I->first->use_empty())
3934         I->first->replaceAllUsesWith(I->second);
3935       I->first->eraseFromParent();
3936     }
3937   }
3938   std::vector<std::pair<Function*, Function*> >().swap(UpgradedIntrinsics);
3939 
3940   for (unsigned I = 0, E = InstsWithTBAATag.size(); I < E; I++)
3941     UpgradeInstWithTBAATag(InstsWithTBAATag[I]);
3942 
3943   UpgradeDebugInfo(*M);
3944   return std::error_code();
3945 }
3946 
3947 std::vector<StructType *> BitcodeReader::getIdentifiedStructTypes() const {
3948   return IdentifiedStructTypes;
3949 }
3950 
3951 std::error_code BitcodeReader::InitStream() {
3952   if (LazyStreamer)
3953     return InitLazyStream();
3954   return InitStreamFromBuffer();
3955 }
3956 
3957 std::error_code BitcodeReader::InitStreamFromBuffer() {
3958   const unsigned char *BufPtr = (const unsigned char*)Buffer->getBufferStart();
3959   const unsigned char *BufEnd = BufPtr+Buffer->getBufferSize();
3960 
3961   if (Buffer->getBufferSize() & 3)
3962     return Error("Invalid bitcode signature");
3963 
3964   // If we have a wrapper header, parse it and ignore the non-bc file contents.
3965   // The magic number is 0x0B17C0DE stored in little endian.
3966   if (isBitcodeWrapper(BufPtr, BufEnd))
3967     if (SkipBitcodeWrapperHeader(BufPtr, BufEnd, true))
3968       return Error("Invalid bitcode wrapper header");
3969 
3970   StreamFile.reset(new BitstreamReader(BufPtr, BufEnd));
3971   Stream.init(&*StreamFile);
3972 
3973   return std::error_code();
3974 }
3975 
3976 std::error_code BitcodeReader::InitLazyStream() {
3977   // Check and strip off the bitcode wrapper; BitstreamReader expects never to
3978   // see it.
3979   auto OwnedBytes = llvm::make_unique<StreamingMemoryObject>(LazyStreamer);
3980   StreamingMemoryObject &Bytes = *OwnedBytes;
3981   StreamFile = llvm::make_unique<BitstreamReader>(std::move(OwnedBytes));
3982   Stream.init(&*StreamFile);
3983 
3984   unsigned char buf[16];
3985   if (Bytes.readBytes(buf, 16, 0) != 16)
3986     return Error("Invalid bitcode signature");
3987 
3988   if (!isBitcode(buf, buf + 16))
3989     return Error("Invalid bitcode signature");
3990 
3991   if (isBitcodeWrapper(buf, buf + 4)) {
3992     const unsigned char *bitcodeStart = buf;
3993     const unsigned char *bitcodeEnd = buf + 16;
3994     SkipBitcodeWrapperHeader(bitcodeStart, bitcodeEnd, false);
3995     Bytes.dropLeadingBytes(bitcodeStart - buf);
3996     Bytes.setKnownObjectSize(bitcodeEnd - bitcodeStart);
3997   }
3998   return std::error_code();
3999 }
4000 
4001 namespace {
4002 class BitcodeErrorCategoryType : public std::error_category {
4003   const char *name() const LLVM_NOEXCEPT override {
4004     return "llvm.bitcode";
4005   }
4006   std::string message(int IE) const override {
4007     BitcodeError E = static_cast<BitcodeError>(IE);
4008     switch (E) {
4009     case BitcodeError::InvalidBitcodeSignature:
4010       return "Invalid bitcode signature";
4011     case BitcodeError::CorruptedBitcode:
4012       return "Corrupted bitcode";
4013     }
4014     llvm_unreachable("Unknown error type!");
4015   }
4016 };
4017 }
4018 
4019 static ManagedStatic<BitcodeErrorCategoryType> ErrorCategory;
4020 
4021 const std::error_category &llvm::BitcodeErrorCategory() {
4022   return *ErrorCategory;
4023 }
4024 
4025 //===----------------------------------------------------------------------===//
4026 // External interface
4027 //===----------------------------------------------------------------------===//
4028 
4029 /// \brief Get a lazy one-at-time loading module from bitcode.
4030 ///
4031 /// This isn't always used in a lazy context.  In particular, it's also used by
4032 /// \a parseBitcodeFile().  If this is truly lazy, then we need to eagerly pull
4033 /// in forward-referenced functions from block address references.
4034 ///
4035 /// \param[in] WillMaterializeAll Set to \c true if the caller promises to
4036 /// materialize everything -- in particular, if this isn't truly lazy.
4037 static ErrorOr<Module *>
4038 getLazyBitcodeModuleImpl(std::unique_ptr<MemoryBuffer> &&Buffer,
4039                          LLVMContext &Context, bool WillMaterializeAll,
4040                          DiagnosticHandlerFunction DiagnosticHandler) {
4041   Module *M = new Module(Buffer->getBufferIdentifier(), Context);
4042   BitcodeReader *R =
4043       new BitcodeReader(Buffer.get(), Context, DiagnosticHandler);
4044   M->setMaterializer(R);
4045 
4046   auto cleanupOnError = [&](std::error_code EC) {
4047     R->releaseBuffer(); // Never take ownership on error.
4048     delete M;  // Also deletes R.
4049     return EC;
4050   };
4051 
4052   if (std::error_code EC = R->ParseBitcodeInto(M))
4053     return cleanupOnError(EC);
4054 
4055   if (!WillMaterializeAll)
4056     // Resolve forward references from blockaddresses.
4057     if (std::error_code EC = R->materializeForwardReferencedFunctions())
4058       return cleanupOnError(EC);
4059 
4060   Buffer.release(); // The BitcodeReader owns it now.
4061   return M;
4062 }
4063 
4064 ErrorOr<Module *>
4065 llvm::getLazyBitcodeModule(std::unique_ptr<MemoryBuffer> &&Buffer,
4066                            LLVMContext &Context,
4067                            DiagnosticHandlerFunction DiagnosticHandler) {
4068   return getLazyBitcodeModuleImpl(std::move(Buffer), Context, false,
4069                                   DiagnosticHandler);
4070 }
4071 
4072 ErrorOr<std::unique_ptr<Module>>
4073 llvm::getStreamedBitcodeModule(StringRef Name, DataStreamer *Streamer,
4074                                LLVMContext &Context,
4075                                DiagnosticHandlerFunction DiagnosticHandler) {
4076   std::unique_ptr<Module> M = make_unique<Module>(Name, Context);
4077   BitcodeReader *R = new BitcodeReader(Streamer, Context, DiagnosticHandler);
4078   M->setMaterializer(R);
4079   if (std::error_code EC = R->ParseBitcodeInto(M.get()))
4080     return EC;
4081   return std::move(M);
4082 }
4083 
4084 ErrorOr<Module *>
4085 llvm::parseBitcodeFile(MemoryBufferRef Buffer, LLVMContext &Context,
4086                        DiagnosticHandlerFunction DiagnosticHandler) {
4087   std::unique_ptr<MemoryBuffer> Buf = MemoryBuffer::getMemBuffer(Buffer, false);
4088   ErrorOr<Module *> ModuleOrErr = getLazyBitcodeModuleImpl(
4089       std::move(Buf), Context, true, DiagnosticHandler);
4090   if (!ModuleOrErr)
4091     return ModuleOrErr;
4092   Module *M = ModuleOrErr.get();
4093   // Read in the entire module, and destroy the BitcodeReader.
4094   if (std::error_code EC = M->materializeAllPermanently()) {
4095     delete M;
4096     return EC;
4097   }
4098 
4099   // TODO: Restore the use-lists to the in-memory state when the bitcode was
4100   // written.  We must defer until the Module has been fully materialized.
4101 
4102   return M;
4103 }
4104 
4105 std::string
4106 llvm::getBitcodeTargetTriple(MemoryBufferRef Buffer, LLVMContext &Context,
4107                              DiagnosticHandlerFunction DiagnosticHandler) {
4108   std::unique_ptr<MemoryBuffer> Buf = MemoryBuffer::getMemBuffer(Buffer, false);
4109   auto R = llvm::make_unique<BitcodeReader>(Buf.release(), Context,
4110                                             DiagnosticHandler);
4111   ErrorOr<std::string> Triple = R->parseTriple();
4112   if (Triple.getError())
4113     return "";
4114   return Triple.get();
4115 }
4116