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      1 //===-- Type.cpp - Implement the Type class -------------------------------===//
      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 // This file implements the Type class for the VMCore library.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #include "LLVMContextImpl.h"
     15 #include "llvm/Module.h"
     16 #include <algorithm>
     17 #include <cstdarg>
     18 #include "llvm/ADT/SmallString.h"
     19 using namespace llvm;
     20 
     21 //===----------------------------------------------------------------------===//
     22 //                         Type Class Implementation
     23 //===----------------------------------------------------------------------===//
     24 
     25 Type *Type::getPrimitiveType(LLVMContext &C, TypeID IDNumber) {
     26   switch (IDNumber) {
     27   case VoidTyID      : return getVoidTy(C);
     28   case FloatTyID     : return getFloatTy(C);
     29   case DoubleTyID    : return getDoubleTy(C);
     30   case X86_FP80TyID  : return getX86_FP80Ty(C);
     31   case FP128TyID     : return getFP128Ty(C);
     32   case PPC_FP128TyID : return getPPC_FP128Ty(C);
     33   case LabelTyID     : return getLabelTy(C);
     34   case MetadataTyID  : return getMetadataTy(C);
     35   case X86_MMXTyID   : return getX86_MMXTy(C);
     36   default:
     37     return 0;
     38   }
     39 }
     40 
     41 /// getScalarType - If this is a vector type, return the element type,
     42 /// otherwise return this.
     43 Type *Type::getScalarType() {
     44   if (VectorType *VTy = dyn_cast<VectorType>(this))
     45     return VTy->getElementType();
     46   return this;
     47 }
     48 
     49 /// isIntegerTy - Return true if this is an IntegerType of the specified width.
     50 bool Type::isIntegerTy(unsigned Bitwidth) const {
     51   return isIntegerTy() && cast<IntegerType>(this)->getBitWidth() == Bitwidth;
     52 }
     53 
     54 /// isIntOrIntVectorTy - Return true if this is an integer type or a vector of
     55 /// integer types.
     56 ///
     57 bool Type::isIntOrIntVectorTy() const {
     58   if (isIntegerTy())
     59     return true;
     60   if (ID != Type::VectorTyID) return false;
     61 
     62   return cast<VectorType>(this)->getElementType()->isIntegerTy();
     63 }
     64 
     65 /// isFPOrFPVectorTy - Return true if this is a FP type or a vector of FP types.
     66 ///
     67 bool Type::isFPOrFPVectorTy() const {
     68   if (ID == Type::FloatTyID || ID == Type::DoubleTyID ||
     69       ID == Type::FP128TyID || ID == Type::X86_FP80TyID ||
     70       ID == Type::PPC_FP128TyID)
     71     return true;
     72   if (ID != Type::VectorTyID) return false;
     73 
     74   return cast<VectorType>(this)->getElementType()->isFloatingPointTy();
     75 }
     76 
     77 // canLosslesslyBitCastTo - Return true if this type can be converted to
     78 // 'Ty' without any reinterpretation of bits.  For example, i8* to i32*.
     79 //
     80 bool Type::canLosslesslyBitCastTo(Type *Ty) const {
     81   // Identity cast means no change so return true
     82   if (this == Ty)
     83     return true;
     84 
     85   // They are not convertible unless they are at least first class types
     86   if (!this->isFirstClassType() || !Ty->isFirstClassType())
     87     return false;
     88 
     89   // Vector -> Vector conversions are always lossless if the two vector types
     90   // have the same size, otherwise not.  Also, 64-bit vector types can be
     91   // converted to x86mmx.
     92   if (const VectorType *thisPTy = dyn_cast<VectorType>(this)) {
     93     if (const VectorType *thatPTy = dyn_cast<VectorType>(Ty))
     94       return thisPTy->getBitWidth() == thatPTy->getBitWidth();
     95     if (Ty->getTypeID() == Type::X86_MMXTyID &&
     96         thisPTy->getBitWidth() == 64)
     97       return true;
     98   }
     99 
    100   if (this->getTypeID() == Type::X86_MMXTyID)
    101     if (const VectorType *thatPTy = dyn_cast<VectorType>(Ty))
    102       if (thatPTy->getBitWidth() == 64)
    103         return true;
    104 
    105   // At this point we have only various mismatches of the first class types
    106   // remaining and ptr->ptr. Just select the lossless conversions. Everything
    107   // else is not lossless.
    108   if (this->isPointerTy())
    109     return Ty->isPointerTy();
    110   return false;  // Other types have no identity values
    111 }
    112 
    113 bool Type::isEmptyTy() const {
    114   const ArrayType *ATy = dyn_cast<ArrayType>(this);
    115   if (ATy) {
    116     unsigned NumElements = ATy->getNumElements();
    117     return NumElements == 0 || ATy->getElementType()->isEmptyTy();
    118   }
    119 
    120   const StructType *STy = dyn_cast<StructType>(this);
    121   if (STy) {
    122     unsigned NumElements = STy->getNumElements();
    123     for (unsigned i = 0; i < NumElements; ++i)
    124       if (!STy->getElementType(i)->isEmptyTy())
    125         return false;
    126     return true;
    127   }
    128 
    129   return false;
    130 }
    131 
    132 unsigned Type::getPrimitiveSizeInBits() const {
    133   switch (getTypeID()) {
    134   case Type::FloatTyID: return 32;
    135   case Type::DoubleTyID: return 64;
    136   case Type::X86_FP80TyID: return 80;
    137   case Type::FP128TyID: return 128;
    138   case Type::PPC_FP128TyID: return 128;
    139   case Type::X86_MMXTyID: return 64;
    140   case Type::IntegerTyID: return cast<IntegerType>(this)->getBitWidth();
    141   case Type::VectorTyID:  return cast<VectorType>(this)->getBitWidth();
    142   default: return 0;
    143   }
    144 }
    145 
    146 /// getScalarSizeInBits - If this is a vector type, return the
    147 /// getPrimitiveSizeInBits value for the element type. Otherwise return the
    148 /// getPrimitiveSizeInBits value for this type.
    149 unsigned Type::getScalarSizeInBits() {
    150   return getScalarType()->getPrimitiveSizeInBits();
    151 }
    152 
    153 /// getFPMantissaWidth - Return the width of the mantissa of this type.  This
    154 /// is only valid on floating point types.  If the FP type does not
    155 /// have a stable mantissa (e.g. ppc long double), this method returns -1.
    156 int Type::getFPMantissaWidth() const {
    157   if (const VectorType *VTy = dyn_cast<VectorType>(this))
    158     return VTy->getElementType()->getFPMantissaWidth();
    159   assert(isFloatingPointTy() && "Not a floating point type!");
    160   if (ID == FloatTyID) return 24;
    161   if (ID == DoubleTyID) return 53;
    162   if (ID == X86_FP80TyID) return 64;
    163   if (ID == FP128TyID) return 113;
    164   assert(ID == PPC_FP128TyID && "unknown fp type");
    165   return -1;
    166 }
    167 
    168 /// isSizedDerivedType - Derived types like structures and arrays are sized
    169 /// iff all of the members of the type are sized as well.  Since asking for
    170 /// their size is relatively uncommon, move this operation out of line.
    171 bool Type::isSizedDerivedType() const {
    172   if (this->isIntegerTy())
    173     return true;
    174 
    175   if (const ArrayType *ATy = dyn_cast<ArrayType>(this))
    176     return ATy->getElementType()->isSized();
    177 
    178   if (const VectorType *VTy = dyn_cast<VectorType>(this))
    179     return VTy->getElementType()->isSized();
    180 
    181   if (!this->isStructTy())
    182     return false;
    183 
    184   // Opaque structs have no size.
    185   if (cast<StructType>(this)->isOpaque())
    186     return false;
    187 
    188   // Okay, our struct is sized if all of the elements are.
    189   for (subtype_iterator I = subtype_begin(), E = subtype_end(); I != E; ++I)
    190     if (!(*I)->isSized())
    191       return false;
    192 
    193   return true;
    194 }
    195 
    196 //===----------------------------------------------------------------------===//
    197 //                          Primitive 'Type' data
    198 //===----------------------------------------------------------------------===//
    199 
    200 Type *Type::getVoidTy(LLVMContext &C) { return &C.pImpl->VoidTy; }
    201 Type *Type::getLabelTy(LLVMContext &C) { return &C.pImpl->LabelTy; }
    202 Type *Type::getFloatTy(LLVMContext &C) { return &C.pImpl->FloatTy; }
    203 Type *Type::getDoubleTy(LLVMContext &C) { return &C.pImpl->DoubleTy; }
    204 Type *Type::getMetadataTy(LLVMContext &C) { return &C.pImpl->MetadataTy; }
    205 Type *Type::getX86_FP80Ty(LLVMContext &C) { return &C.pImpl->X86_FP80Ty; }
    206 Type *Type::getFP128Ty(LLVMContext &C) { return &C.pImpl->FP128Ty; }
    207 Type *Type::getPPC_FP128Ty(LLVMContext &C) { return &C.pImpl->PPC_FP128Ty; }
    208 Type *Type::getX86_MMXTy(LLVMContext &C) { return &C.pImpl->X86_MMXTy; }
    209 
    210 IntegerType *Type::getInt1Ty(LLVMContext &C) { return &C.pImpl->Int1Ty; }
    211 IntegerType *Type::getInt8Ty(LLVMContext &C) { return &C.pImpl->Int8Ty; }
    212 IntegerType *Type::getInt16Ty(LLVMContext &C) { return &C.pImpl->Int16Ty; }
    213 IntegerType *Type::getInt32Ty(LLVMContext &C) { return &C.pImpl->Int32Ty; }
    214 IntegerType *Type::getInt64Ty(LLVMContext &C) { return &C.pImpl->Int64Ty; }
    215 
    216 IntegerType *Type::getIntNTy(LLVMContext &C, unsigned N) {
    217   return IntegerType::get(C, N);
    218 }
    219 
    220 PointerType *Type::getFloatPtrTy(LLVMContext &C, unsigned AS) {
    221   return getFloatTy(C)->getPointerTo(AS);
    222 }
    223 
    224 PointerType *Type::getDoublePtrTy(LLVMContext &C, unsigned AS) {
    225   return getDoubleTy(C)->getPointerTo(AS);
    226 }
    227 
    228 PointerType *Type::getX86_FP80PtrTy(LLVMContext &C, unsigned AS) {
    229   return getX86_FP80Ty(C)->getPointerTo(AS);
    230 }
    231 
    232 PointerType *Type::getFP128PtrTy(LLVMContext &C, unsigned AS) {
    233   return getFP128Ty(C)->getPointerTo(AS);
    234 }
    235 
    236 PointerType *Type::getPPC_FP128PtrTy(LLVMContext &C, unsigned AS) {
    237   return getPPC_FP128Ty(C)->getPointerTo(AS);
    238 }
    239 
    240 PointerType *Type::getX86_MMXPtrTy(LLVMContext &C, unsigned AS) {
    241   return getX86_MMXTy(C)->getPointerTo(AS);
    242 }
    243 
    244 PointerType *Type::getIntNPtrTy(LLVMContext &C, unsigned N, unsigned AS) {
    245   return getIntNTy(C, N)->getPointerTo(AS);
    246 }
    247 
    248 PointerType *Type::getInt1PtrTy(LLVMContext &C, unsigned AS) {
    249   return getInt1Ty(C)->getPointerTo(AS);
    250 }
    251 
    252 PointerType *Type::getInt8PtrTy(LLVMContext &C, unsigned AS) {
    253   return getInt8Ty(C)->getPointerTo(AS);
    254 }
    255 
    256 PointerType *Type::getInt16PtrTy(LLVMContext &C, unsigned AS) {
    257   return getInt16Ty(C)->getPointerTo(AS);
    258 }
    259 
    260 PointerType *Type::getInt32PtrTy(LLVMContext &C, unsigned AS) {
    261   return getInt32Ty(C)->getPointerTo(AS);
    262 }
    263 
    264 PointerType *Type::getInt64PtrTy(LLVMContext &C, unsigned AS) {
    265   return getInt64Ty(C)->getPointerTo(AS);
    266 }
    267 
    268 
    269 //===----------------------------------------------------------------------===//
    270 //                       IntegerType Implementation
    271 //===----------------------------------------------------------------------===//
    272 
    273 IntegerType *IntegerType::get(LLVMContext &C, unsigned NumBits) {
    274   assert(NumBits >= MIN_INT_BITS && "bitwidth too small");
    275   assert(NumBits <= MAX_INT_BITS && "bitwidth too large");
    276 
    277   // Check for the built-in integer types
    278   switch (NumBits) {
    279   case  1: return cast<IntegerType>(Type::getInt1Ty(C));
    280   case  8: return cast<IntegerType>(Type::getInt8Ty(C));
    281   case 16: return cast<IntegerType>(Type::getInt16Ty(C));
    282   case 32: return cast<IntegerType>(Type::getInt32Ty(C));
    283   case 64: return cast<IntegerType>(Type::getInt64Ty(C));
    284   default:
    285     break;
    286   }
    287 
    288   IntegerType *&Entry = C.pImpl->IntegerTypes[NumBits];
    289 
    290   if (Entry == 0)
    291     Entry = new (C.pImpl->TypeAllocator) IntegerType(C, NumBits);
    292 
    293   return Entry;
    294 }
    295 
    296 bool IntegerType::isPowerOf2ByteWidth() const {
    297   unsigned BitWidth = getBitWidth();
    298   return (BitWidth > 7) && isPowerOf2_32(BitWidth);
    299 }
    300 
    301 APInt IntegerType::getMask() const {
    302   return APInt::getAllOnesValue(getBitWidth());
    303 }
    304 
    305 //===----------------------------------------------------------------------===//
    306 //                       FunctionType Implementation
    307 //===----------------------------------------------------------------------===//
    308 
    309 FunctionType::FunctionType(Type *Result, ArrayRef<Type*> Params,
    310                            bool IsVarArgs)
    311   : Type(Result->getContext(), FunctionTyID) {
    312   Type **SubTys = reinterpret_cast<Type**>(this+1);
    313   assert(isValidReturnType(Result) && "invalid return type for function");
    314   setSubclassData(IsVarArgs);
    315 
    316   SubTys[0] = const_cast<Type*>(Result);
    317 
    318   for (unsigned i = 0, e = Params.size(); i != e; ++i) {
    319     assert(isValidArgumentType(Params[i]) &&
    320            "Not a valid type for function argument!");
    321     SubTys[i+1] = Params[i];
    322   }
    323 
    324   ContainedTys = SubTys;
    325   NumContainedTys = Params.size() + 1; // + 1 for result type
    326 }
    327 
    328 // FunctionType::get - The factory function for the FunctionType class.
    329 FunctionType *FunctionType::get(Type *ReturnType,
    330                                 ArrayRef<Type*> Params, bool isVarArg) {
    331   // TODO: This is brutally slow.
    332   std::vector<Type*> Key;
    333   Key.reserve(Params.size()+2);
    334   Key.push_back(const_cast<Type*>(ReturnType));
    335   for (unsigned i = 0, e = Params.size(); i != e; ++i)
    336     Key.push_back(const_cast<Type*>(Params[i]));
    337   if (isVarArg)
    338     Key.push_back(0);
    339 
    340   LLVMContextImpl *pImpl = ReturnType->getContext().pImpl;
    341   FunctionType *&FT = pImpl->FunctionTypes[Key];
    342 
    343   if (FT == 0) {
    344     FT = (FunctionType*) pImpl->TypeAllocator.
    345       Allocate(sizeof(FunctionType) + sizeof(Type*)*(Params.size()+1),
    346                AlignOf<FunctionType>::Alignment);
    347     new (FT) FunctionType(ReturnType, Params, isVarArg);
    348   }
    349 
    350   return FT;
    351 }
    352 
    353 
    354 FunctionType *FunctionType::get(Type *Result, bool isVarArg) {
    355   return get(Result, ArrayRef<Type *>(), isVarArg);
    356 }
    357 
    358 
    359 /// isValidReturnType - Return true if the specified type is valid as a return
    360 /// type.
    361 bool FunctionType::isValidReturnType(Type *RetTy) {
    362   return !RetTy->isFunctionTy() && !RetTy->isLabelTy() &&
    363   !RetTy->isMetadataTy();
    364 }
    365 
    366 /// isValidArgumentType - Return true if the specified type is valid as an
    367 /// argument type.
    368 bool FunctionType::isValidArgumentType(Type *ArgTy) {
    369   return ArgTy->isFirstClassType();
    370 }
    371 
    372 //===----------------------------------------------------------------------===//
    373 //                       StructType Implementation
    374 //===----------------------------------------------------------------------===//
    375 
    376 // Primitive Constructors.
    377 
    378 StructType *StructType::get(LLVMContext &Context, ArrayRef<Type*> ETypes,
    379                             bool isPacked) {
    380   // FIXME: std::vector is horribly inefficient for this probe.
    381   std::vector<Type*> Key;
    382   for (unsigned i = 0, e = ETypes.size(); i != e; ++i) {
    383     assert(isValidElementType(ETypes[i]) &&
    384            "Invalid type for structure element!");
    385     Key.push_back(ETypes[i]);
    386   }
    387   if (isPacked)
    388     Key.push_back(0);
    389 
    390   StructType *&ST = Context.pImpl->AnonStructTypes[Key];
    391   if (ST) return ST;
    392 
    393   // Value not found.  Create a new type!
    394   ST = new (Context.pImpl->TypeAllocator) StructType(Context);
    395   ST->setSubclassData(SCDB_IsLiteral);  // Literal struct.
    396   ST->setBody(ETypes, isPacked);
    397   return ST;
    398 }
    399 
    400 void StructType::setBody(ArrayRef<Type*> Elements, bool isPacked) {
    401   assert(isOpaque() && "Struct body already set!");
    402 
    403   setSubclassData(getSubclassData() | SCDB_HasBody);
    404   if (isPacked)
    405     setSubclassData(getSubclassData() | SCDB_Packed);
    406 
    407   Type **Elts = getContext().pImpl->
    408     TypeAllocator.Allocate<Type*>(Elements.size());
    409   memcpy(Elts, Elements.data(), sizeof(Elements[0])*Elements.size());
    410 
    411   ContainedTys = Elts;
    412   NumContainedTys = Elements.size();
    413 }
    414 
    415 void StructType::setName(StringRef Name) {
    416   if (Name == getName()) return;
    417 
    418   // If this struct already had a name, remove its symbol table entry.
    419   if (SymbolTableEntry) {
    420     getContext().pImpl->NamedStructTypes.erase(getName());
    421     SymbolTableEntry = 0;
    422   }
    423 
    424   // If this is just removing the name, we're done.
    425   if (Name.empty())
    426     return;
    427 
    428   // Look up the entry for the name.
    429   StringMapEntry<StructType*> *Entry =
    430     &getContext().pImpl->NamedStructTypes.GetOrCreateValue(Name);
    431 
    432   // While we have a name collision, try a random rename.
    433   if (Entry->getValue()) {
    434     SmallString<64> TempStr(Name);
    435     TempStr.push_back('.');
    436     raw_svector_ostream TmpStream(TempStr);
    437 
    438     do {
    439       TempStr.resize(Name.size()+1);
    440       TmpStream.resync();
    441       TmpStream << getContext().pImpl->NamedStructTypesUniqueID++;
    442 
    443       Entry = &getContext().pImpl->
    444                  NamedStructTypes.GetOrCreateValue(TmpStream.str());
    445     } while (Entry->getValue());
    446   }
    447 
    448   // Okay, we found an entry that isn't used.  It's us!
    449   Entry->setValue(this);
    450 
    451   SymbolTableEntry = Entry;
    452 }
    453 
    454 //===----------------------------------------------------------------------===//
    455 // StructType Helper functions.
    456 
    457 StructType *StructType::create(LLVMContext &Context, StringRef Name) {
    458   StructType *ST = new (Context.pImpl->TypeAllocator) StructType(Context);
    459   if (!Name.empty())
    460     ST->setName(Name);
    461   return ST;
    462 }
    463 
    464 StructType *StructType::get(LLVMContext &Context, bool isPacked) {
    465   return get(Context, llvm::ArrayRef<Type*>(), isPacked);
    466 }
    467 
    468 StructType *StructType::get(Type *type, ...) {
    469   assert(type != 0 && "Cannot create a struct type with no elements with this");
    470   LLVMContext &Ctx = type->getContext();
    471   va_list ap;
    472   SmallVector<llvm::Type*, 8> StructFields;
    473   va_start(ap, type);
    474   while (type) {
    475     StructFields.push_back(type);
    476     type = va_arg(ap, llvm::Type*);
    477   }
    478   return llvm::StructType::get(Ctx, StructFields);
    479 }
    480 
    481 StructType *StructType::create(LLVMContext &Context, ArrayRef<Type*> Elements,
    482                                StringRef Name, bool isPacked) {
    483   StructType *ST = create(Context, Name);
    484   ST->setBody(Elements, isPacked);
    485   return ST;
    486 }
    487 
    488 StructType *StructType::create(LLVMContext &Context, ArrayRef<Type*> Elements) {
    489   return create(Context, Elements, StringRef());
    490 }
    491 
    492 StructType *StructType::create(LLVMContext &Context) {
    493   return create(Context, StringRef());
    494 }
    495 
    496 
    497 StructType *StructType::create(ArrayRef<Type*> Elements, StringRef Name,
    498                                bool isPacked) {
    499   assert(!Elements.empty() &&
    500          "This method may not be invoked with an empty list");
    501   return create(Elements[0]->getContext(), Elements, Name, isPacked);
    502 }
    503 
    504 StructType *StructType::create(ArrayRef<Type*> Elements) {
    505   assert(!Elements.empty() &&
    506          "This method may not be invoked with an empty list");
    507   return create(Elements[0]->getContext(), Elements, StringRef());
    508 }
    509 
    510 StructType *StructType::create(StringRef Name, Type *type, ...) {
    511   assert(type != 0 && "Cannot create a struct type with no elements with this");
    512   LLVMContext &Ctx = type->getContext();
    513   va_list ap;
    514   SmallVector<llvm::Type*, 8> StructFields;
    515   va_start(ap, type);
    516   while (type) {
    517     StructFields.push_back(type);
    518     type = va_arg(ap, llvm::Type*);
    519   }
    520   return llvm::StructType::create(Ctx, StructFields, Name);
    521 }
    522 
    523 
    524 StringRef StructType::getName() const {
    525   assert(!isLiteral() && "Literal structs never have names");
    526   if (SymbolTableEntry == 0) return StringRef();
    527 
    528   return ((StringMapEntry<StructType*> *)SymbolTableEntry)->getKey();
    529 }
    530 
    531 void StructType::setBody(Type *type, ...) {
    532   assert(type != 0 && "Cannot create a struct type with no elements with this");
    533   va_list ap;
    534   SmallVector<llvm::Type*, 8> StructFields;
    535   va_start(ap, type);
    536   while (type) {
    537     StructFields.push_back(type);
    538     type = va_arg(ap, llvm::Type*);
    539   }
    540   setBody(StructFields);
    541 }
    542 
    543 bool StructType::isValidElementType(Type *ElemTy) {
    544   return !ElemTy->isVoidTy() && !ElemTy->isLabelTy() &&
    545          !ElemTy->isMetadataTy() && !ElemTy->isFunctionTy();
    546 }
    547 
    548 /// isLayoutIdentical - Return true if this is layout identical to the
    549 /// specified struct.
    550 bool StructType::isLayoutIdentical(StructType *Other) const {
    551   if (this == Other) return true;
    552 
    553   if (isPacked() != Other->isPacked() ||
    554       getNumElements() != Other->getNumElements())
    555     return false;
    556 
    557   return std::equal(element_begin(), element_end(), Other->element_begin());
    558 }
    559 
    560 
    561 /// getTypeByName - Return the type with the specified name, or null if there
    562 /// is none by that name.
    563 StructType *Module::getTypeByName(StringRef Name) const {
    564   StringMap<StructType*>::iterator I =
    565     getContext().pImpl->NamedStructTypes.find(Name);
    566   if (I != getContext().pImpl->NamedStructTypes.end())
    567     return I->second;
    568   return 0;
    569 }
    570 
    571 
    572 //===----------------------------------------------------------------------===//
    573 //                       CompositeType Implementation
    574 //===----------------------------------------------------------------------===//
    575 
    576 Type *CompositeType::getTypeAtIndex(const Value *V) {
    577   if (StructType *STy = dyn_cast<StructType>(this)) {
    578     unsigned Idx = (unsigned)cast<ConstantInt>(V)->getZExtValue();
    579     assert(indexValid(Idx) && "Invalid structure index!");
    580     return STy->getElementType(Idx);
    581   }
    582 
    583   return cast<SequentialType>(this)->getElementType();
    584 }
    585 Type *CompositeType::getTypeAtIndex(unsigned Idx) {
    586   if (StructType *STy = dyn_cast<StructType>(this)) {
    587     assert(indexValid(Idx) && "Invalid structure index!");
    588     return STy->getElementType(Idx);
    589   }
    590 
    591   return cast<SequentialType>(this)->getElementType();
    592 }
    593 bool CompositeType::indexValid(const Value *V) const {
    594   if (const StructType *STy = dyn_cast<StructType>(this)) {
    595     // Structure indexes require 32-bit integer constants.
    596     if (V->getType()->isIntegerTy(32))
    597       if (const ConstantInt *CU = dyn_cast<ConstantInt>(V))
    598         return CU->getZExtValue() < STy->getNumElements();
    599     return false;
    600   }
    601 
    602   // Sequential types can be indexed by any integer.
    603   return V->getType()->isIntegerTy();
    604 }
    605 
    606 bool CompositeType::indexValid(unsigned Idx) const {
    607   if (const StructType *STy = dyn_cast<StructType>(this))
    608     return Idx < STy->getNumElements();
    609   // Sequential types can be indexed by any integer.
    610   return true;
    611 }
    612 
    613 
    614 //===----------------------------------------------------------------------===//
    615 //                           ArrayType Implementation
    616 //===----------------------------------------------------------------------===//
    617 
    618 ArrayType::ArrayType(Type *ElType, uint64_t NumEl)
    619   : SequentialType(ArrayTyID, ElType) {
    620   NumElements = NumEl;
    621 }
    622 
    623 
    624 ArrayType *ArrayType::get(Type *elementType, uint64_t NumElements) {
    625   Type *ElementType = const_cast<Type*>(elementType);
    626   assert(isValidElementType(ElementType) && "Invalid type for array element!");
    627 
    628   LLVMContextImpl *pImpl = ElementType->getContext().pImpl;
    629   ArrayType *&Entry =
    630     pImpl->ArrayTypes[std::make_pair(ElementType, NumElements)];
    631 
    632   if (Entry == 0)
    633     Entry = new (pImpl->TypeAllocator) ArrayType(ElementType, NumElements);
    634   return Entry;
    635 }
    636 
    637 bool ArrayType::isValidElementType(Type *ElemTy) {
    638   return !ElemTy->isVoidTy() && !ElemTy->isLabelTy() &&
    639          !ElemTy->isMetadataTy() && !ElemTy->isFunctionTy();
    640 }
    641 
    642 //===----------------------------------------------------------------------===//
    643 //                          VectorType Implementation
    644 //===----------------------------------------------------------------------===//
    645 
    646 VectorType::VectorType(Type *ElType, unsigned NumEl)
    647   : SequentialType(VectorTyID, ElType) {
    648   NumElements = NumEl;
    649 }
    650 
    651 VectorType *VectorType::get(Type *elementType, unsigned NumElements) {
    652   Type *ElementType = const_cast<Type*>(elementType);
    653   assert(NumElements > 0 && "#Elements of a VectorType must be greater than 0");
    654   assert(isValidElementType(ElementType) &&
    655          "Elements of a VectorType must be a primitive type");
    656 
    657   LLVMContextImpl *pImpl = ElementType->getContext().pImpl;
    658   VectorType *&Entry = ElementType->getContext().pImpl
    659     ->VectorTypes[std::make_pair(ElementType, NumElements)];
    660 
    661   if (Entry == 0)
    662     Entry = new (pImpl->TypeAllocator) VectorType(ElementType, NumElements);
    663   return Entry;
    664 }
    665 
    666 bool VectorType::isValidElementType(Type *ElemTy) {
    667   return ElemTy->isIntegerTy() || ElemTy->isFloatingPointTy();
    668 }
    669 
    670 //===----------------------------------------------------------------------===//
    671 //                         PointerType Implementation
    672 //===----------------------------------------------------------------------===//
    673 
    674 PointerType *PointerType::get(Type *EltTy, unsigned AddressSpace) {
    675   assert(EltTy && "Can't get a pointer to <null> type!");
    676   assert(isValidElementType(EltTy) && "Invalid type for pointer element!");
    677 
    678   LLVMContextImpl *CImpl = EltTy->getContext().pImpl;
    679 
    680   // Since AddressSpace #0 is the common case, we special case it.
    681   PointerType *&Entry = AddressSpace == 0 ? CImpl->PointerTypes[EltTy]
    682      : CImpl->ASPointerTypes[std::make_pair(EltTy, AddressSpace)];
    683 
    684   if (Entry == 0)
    685     Entry = new (CImpl->TypeAllocator) PointerType(EltTy, AddressSpace);
    686   return Entry;
    687 }
    688 
    689 
    690 PointerType::PointerType(Type *E, unsigned AddrSpace)
    691   : SequentialType(PointerTyID, E) {
    692   setSubclassData(AddrSpace);
    693 }
    694 
    695 PointerType *Type::getPointerTo(unsigned addrs) {
    696   return PointerType::get(this, addrs);
    697 }
    698 
    699 bool PointerType::isValidElementType(Type *ElemTy) {
    700   return !ElemTy->isVoidTy() && !ElemTy->isLabelTy() &&
    701          !ElemTy->isMetadataTy();
    702 }
    703