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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 IR library.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #include "llvm/IR/Type.h"
     15 #include "LLVMContextImpl.h"
     16 #include "llvm/ADT/SmallString.h"
     17 #include "llvm/IR/Module.h"
     18 #include <algorithm>
     19 #include <cstdarg>
     20 using namespace llvm;
     21 
     22 //===----------------------------------------------------------------------===//
     23 //                         Type Class Implementation
     24 //===----------------------------------------------------------------------===//
     25 
     26 Type *Type::getPrimitiveType(LLVMContext &C, TypeID IDNumber) {
     27   switch (IDNumber) {
     28   case VoidTyID      : return getVoidTy(C);
     29   case HalfTyID      : return getHalfTy(C);
     30   case FloatTyID     : return getFloatTy(C);
     31   case DoubleTyID    : return getDoubleTy(C);
     32   case X86_FP80TyID  : return getX86_FP80Ty(C);
     33   case FP128TyID     : return getFP128Ty(C);
     34   case PPC_FP128TyID : return getPPC_FP128Ty(C);
     35   case LabelTyID     : return getLabelTy(C);
     36   case MetadataTyID  : return getMetadataTy(C);
     37   case X86_MMXTyID   : return getX86_MMXTy(C);
     38   default:
     39     return nullptr;
     40   }
     41 }
     42 
     43 /// getScalarType - If this is a vector type, return the element type,
     44 /// otherwise return this.
     45 Type *Type::getScalarType() {
     46   if (VectorType *VTy = dyn_cast<VectorType>(this))
     47     return VTy->getElementType();
     48   return this;
     49 }
     50 
     51 const Type *Type::getScalarType() const {
     52   if (const VectorType *VTy = dyn_cast<VectorType>(this))
     53     return VTy->getElementType();
     54   return this;
     55 }
     56 
     57 /// isIntegerTy - Return true if this is an IntegerType of the specified width.
     58 bool Type::isIntegerTy(unsigned Bitwidth) const {
     59   return isIntegerTy() && cast<IntegerType>(this)->getBitWidth() == Bitwidth;
     60 }
     61 
     62 // canLosslesslyBitCastTo - Return true if this type can be converted to
     63 // 'Ty' without any reinterpretation of bits.  For example, i8* to i32*.
     64 //
     65 bool Type::canLosslesslyBitCastTo(Type *Ty) const {
     66   // Identity cast means no change so return true
     67   if (this == Ty)
     68     return true;
     69 
     70   // They are not convertible unless they are at least first class types
     71   if (!this->isFirstClassType() || !Ty->isFirstClassType())
     72     return false;
     73 
     74   // Vector -> Vector conversions are always lossless if the two vector types
     75   // have the same size, otherwise not.  Also, 64-bit vector types can be
     76   // converted to x86mmx.
     77   if (const VectorType *thisPTy = dyn_cast<VectorType>(this)) {
     78     if (const VectorType *thatPTy = dyn_cast<VectorType>(Ty))
     79       return thisPTy->getBitWidth() == thatPTy->getBitWidth();
     80     if (Ty->getTypeID() == Type::X86_MMXTyID &&
     81         thisPTy->getBitWidth() == 64)
     82       return true;
     83   }
     84 
     85   if (this->getTypeID() == Type::X86_MMXTyID)
     86     if (const VectorType *thatPTy = dyn_cast<VectorType>(Ty))
     87       if (thatPTy->getBitWidth() == 64)
     88         return true;
     89 
     90   // At this point we have only various mismatches of the first class types
     91   // remaining and ptr->ptr. Just select the lossless conversions. Everything
     92   // else is not lossless.
     93   if (this->isPointerTy())
     94     return Ty->isPointerTy();
     95   return false;  // Other types have no identity values
     96 }
     97 
     98 bool Type::isEmptyTy() const {
     99   const ArrayType *ATy = dyn_cast<ArrayType>(this);
    100   if (ATy) {
    101     unsigned NumElements = ATy->getNumElements();
    102     return NumElements == 0 || ATy->getElementType()->isEmptyTy();
    103   }
    104 
    105   const StructType *STy = dyn_cast<StructType>(this);
    106   if (STy) {
    107     unsigned NumElements = STy->getNumElements();
    108     for (unsigned i = 0; i < NumElements; ++i)
    109       if (!STy->getElementType(i)->isEmptyTy())
    110         return false;
    111     return true;
    112   }
    113 
    114   return false;
    115 }
    116 
    117 unsigned Type::getPrimitiveSizeInBits() const {
    118   switch (getTypeID()) {
    119   case Type::HalfTyID: return 16;
    120   case Type::FloatTyID: return 32;
    121   case Type::DoubleTyID: return 64;
    122   case Type::X86_FP80TyID: return 80;
    123   case Type::FP128TyID: return 128;
    124   case Type::PPC_FP128TyID: return 128;
    125   case Type::X86_MMXTyID: return 64;
    126   case Type::IntegerTyID: return cast<IntegerType>(this)->getBitWidth();
    127   case Type::VectorTyID:  return cast<VectorType>(this)->getBitWidth();
    128   default: return 0;
    129   }
    130 }
    131 
    132 /// getScalarSizeInBits - If this is a vector type, return the
    133 /// getPrimitiveSizeInBits value for the element type. Otherwise return the
    134 /// getPrimitiveSizeInBits value for this type.
    135 unsigned Type::getScalarSizeInBits() const {
    136   return getScalarType()->getPrimitiveSizeInBits();
    137 }
    138 
    139 /// getFPMantissaWidth - Return the width of the mantissa of this type.  This
    140 /// is only valid on floating point types.  If the FP type does not
    141 /// have a stable mantissa (e.g. ppc long double), this method returns -1.
    142 int Type::getFPMantissaWidth() const {
    143   if (const VectorType *VTy = dyn_cast<VectorType>(this))
    144     return VTy->getElementType()->getFPMantissaWidth();
    145   assert(isFloatingPointTy() && "Not a floating point type!");
    146   if (getTypeID() == HalfTyID) return 11;
    147   if (getTypeID() == FloatTyID) return 24;
    148   if (getTypeID() == DoubleTyID) return 53;
    149   if (getTypeID() == X86_FP80TyID) return 64;
    150   if (getTypeID() == FP128TyID) return 113;
    151   assert(getTypeID() == PPC_FP128TyID && "unknown fp type");
    152   return -1;
    153 }
    154 
    155 /// isSizedDerivedType - Derived types like structures and arrays are sized
    156 /// iff all of the members of the type are sized as well.  Since asking for
    157 /// their size is relatively uncommon, move this operation out of line.
    158 bool Type::isSizedDerivedType(SmallPtrSet<const Type*, 4> *Visited) const {
    159   if (const ArrayType *ATy = dyn_cast<ArrayType>(this))
    160     return ATy->getElementType()->isSized(Visited);
    161 
    162   if (const VectorType *VTy = dyn_cast<VectorType>(this))
    163     return VTy->getElementType()->isSized(Visited);
    164 
    165   return cast<StructType>(this)->isSized(Visited);
    166 }
    167 
    168 //===----------------------------------------------------------------------===//
    169 //                         Subclass Helper Methods
    170 //===----------------------------------------------------------------------===//
    171 
    172 unsigned Type::getIntegerBitWidth() const {
    173   return cast<IntegerType>(this)->getBitWidth();
    174 }
    175 
    176 bool Type::isFunctionVarArg() const {
    177   return cast<FunctionType>(this)->isVarArg();
    178 }
    179 
    180 Type *Type::getFunctionParamType(unsigned i) const {
    181   return cast<FunctionType>(this)->getParamType(i);
    182 }
    183 
    184 unsigned Type::getFunctionNumParams() const {
    185   return cast<FunctionType>(this)->getNumParams();
    186 }
    187 
    188 StringRef Type::getStructName() const {
    189   return cast<StructType>(this)->getName();
    190 }
    191 
    192 unsigned Type::getStructNumElements() const {
    193   return cast<StructType>(this)->getNumElements();
    194 }
    195 
    196 Type *Type::getStructElementType(unsigned N) const {
    197   return cast<StructType>(this)->getElementType(N);
    198 }
    199 
    200 Type *Type::getSequentialElementType() const {
    201   return cast<SequentialType>(this)->getElementType();
    202 }
    203 
    204 uint64_t Type::getArrayNumElements() const {
    205   return cast<ArrayType>(this)->getNumElements();
    206 }
    207 
    208 unsigned Type::getVectorNumElements() const {
    209   return cast<VectorType>(this)->getNumElements();
    210 }
    211 
    212 unsigned Type::getPointerAddressSpace() const {
    213   return cast<PointerType>(getScalarType())->getAddressSpace();
    214 }
    215 
    216 
    217 //===----------------------------------------------------------------------===//
    218 //                          Primitive 'Type' data
    219 //===----------------------------------------------------------------------===//
    220 
    221 Type *Type::getVoidTy(LLVMContext &C) { return &C.pImpl->VoidTy; }
    222 Type *Type::getLabelTy(LLVMContext &C) { return &C.pImpl->LabelTy; }
    223 Type *Type::getHalfTy(LLVMContext &C) { return &C.pImpl->HalfTy; }
    224 Type *Type::getFloatTy(LLVMContext &C) { return &C.pImpl->FloatTy; }
    225 Type *Type::getDoubleTy(LLVMContext &C) { return &C.pImpl->DoubleTy; }
    226 Type *Type::getMetadataTy(LLVMContext &C) { return &C.pImpl->MetadataTy; }
    227 Type *Type::getX86_FP80Ty(LLVMContext &C) { return &C.pImpl->X86_FP80Ty; }
    228 Type *Type::getFP128Ty(LLVMContext &C) { return &C.pImpl->FP128Ty; }
    229 Type *Type::getPPC_FP128Ty(LLVMContext &C) { return &C.pImpl->PPC_FP128Ty; }
    230 Type *Type::getX86_MMXTy(LLVMContext &C) { return &C.pImpl->X86_MMXTy; }
    231 
    232 IntegerType *Type::getInt1Ty(LLVMContext &C) { return &C.pImpl->Int1Ty; }
    233 IntegerType *Type::getInt8Ty(LLVMContext &C) { return &C.pImpl->Int8Ty; }
    234 IntegerType *Type::getInt16Ty(LLVMContext &C) { return &C.pImpl->Int16Ty; }
    235 IntegerType *Type::getInt32Ty(LLVMContext &C) { return &C.pImpl->Int32Ty; }
    236 IntegerType *Type::getInt64Ty(LLVMContext &C) { return &C.pImpl->Int64Ty; }
    237 
    238 IntegerType *Type::getIntNTy(LLVMContext &C, unsigned N) {
    239   return IntegerType::get(C, N);
    240 }
    241 
    242 PointerType *Type::getHalfPtrTy(LLVMContext &C, unsigned AS) {
    243   return getHalfTy(C)->getPointerTo(AS);
    244 }
    245 
    246 PointerType *Type::getFloatPtrTy(LLVMContext &C, unsigned AS) {
    247   return getFloatTy(C)->getPointerTo(AS);
    248 }
    249 
    250 PointerType *Type::getDoublePtrTy(LLVMContext &C, unsigned AS) {
    251   return getDoubleTy(C)->getPointerTo(AS);
    252 }
    253 
    254 PointerType *Type::getX86_FP80PtrTy(LLVMContext &C, unsigned AS) {
    255   return getX86_FP80Ty(C)->getPointerTo(AS);
    256 }
    257 
    258 PointerType *Type::getFP128PtrTy(LLVMContext &C, unsigned AS) {
    259   return getFP128Ty(C)->getPointerTo(AS);
    260 }
    261 
    262 PointerType *Type::getPPC_FP128PtrTy(LLVMContext &C, unsigned AS) {
    263   return getPPC_FP128Ty(C)->getPointerTo(AS);
    264 }
    265 
    266 PointerType *Type::getX86_MMXPtrTy(LLVMContext &C, unsigned AS) {
    267   return getX86_MMXTy(C)->getPointerTo(AS);
    268 }
    269 
    270 PointerType *Type::getIntNPtrTy(LLVMContext &C, unsigned N, unsigned AS) {
    271   return getIntNTy(C, N)->getPointerTo(AS);
    272 }
    273 
    274 PointerType *Type::getInt1PtrTy(LLVMContext &C, unsigned AS) {
    275   return getInt1Ty(C)->getPointerTo(AS);
    276 }
    277 
    278 PointerType *Type::getInt8PtrTy(LLVMContext &C, unsigned AS) {
    279   return getInt8Ty(C)->getPointerTo(AS);
    280 }
    281 
    282 PointerType *Type::getInt16PtrTy(LLVMContext &C, unsigned AS) {
    283   return getInt16Ty(C)->getPointerTo(AS);
    284 }
    285 
    286 PointerType *Type::getInt32PtrTy(LLVMContext &C, unsigned AS) {
    287   return getInt32Ty(C)->getPointerTo(AS);
    288 }
    289 
    290 PointerType *Type::getInt64PtrTy(LLVMContext &C, unsigned AS) {
    291   return getInt64Ty(C)->getPointerTo(AS);
    292 }
    293 
    294 
    295 //===----------------------------------------------------------------------===//
    296 //                       IntegerType Implementation
    297 //===----------------------------------------------------------------------===//
    298 
    299 IntegerType *IntegerType::get(LLVMContext &C, unsigned NumBits) {
    300   assert(NumBits >= MIN_INT_BITS && "bitwidth too small");
    301   assert(NumBits <= MAX_INT_BITS && "bitwidth too large");
    302 
    303   // Check for the built-in integer types
    304   switch (NumBits) {
    305   case  1: return cast<IntegerType>(Type::getInt1Ty(C));
    306   case  8: return cast<IntegerType>(Type::getInt8Ty(C));
    307   case 16: return cast<IntegerType>(Type::getInt16Ty(C));
    308   case 32: return cast<IntegerType>(Type::getInt32Ty(C));
    309   case 64: return cast<IntegerType>(Type::getInt64Ty(C));
    310   default:
    311     break;
    312   }
    313 
    314   IntegerType *&Entry = C.pImpl->IntegerTypes[NumBits];
    315 
    316   if (!Entry)
    317     Entry = new (C.pImpl->TypeAllocator) IntegerType(C, NumBits);
    318 
    319   return Entry;
    320 }
    321 
    322 bool IntegerType::isPowerOf2ByteWidth() const {
    323   unsigned BitWidth = getBitWidth();
    324   return (BitWidth > 7) && isPowerOf2_32(BitWidth);
    325 }
    326 
    327 APInt IntegerType::getMask() const {
    328   return APInt::getAllOnesValue(getBitWidth());
    329 }
    330 
    331 //===----------------------------------------------------------------------===//
    332 //                       FunctionType Implementation
    333 //===----------------------------------------------------------------------===//
    334 
    335 FunctionType::FunctionType(Type *Result, ArrayRef<Type*> Params,
    336                            bool IsVarArgs)
    337   : Type(Result->getContext(), FunctionTyID) {
    338   Type **SubTys = reinterpret_cast<Type**>(this+1);
    339   assert(isValidReturnType(Result) && "invalid return type for function");
    340   setSubclassData(IsVarArgs);
    341 
    342   SubTys[0] = const_cast<Type*>(Result);
    343 
    344   for (unsigned i = 0, e = Params.size(); i != e; ++i) {
    345     assert(isValidArgumentType(Params[i]) &&
    346            "Not a valid type for function argument!");
    347     SubTys[i+1] = Params[i];
    348   }
    349 
    350   ContainedTys = SubTys;
    351   NumContainedTys = Params.size() + 1; // + 1 for result type
    352 }
    353 
    354 // FunctionType::get - The factory function for the FunctionType class.
    355 FunctionType *FunctionType::get(Type *ReturnType,
    356                                 ArrayRef<Type*> Params, bool isVarArg) {
    357   LLVMContextImpl *pImpl = ReturnType->getContext().pImpl;
    358   FunctionTypeKeyInfo::KeyTy Key(ReturnType, Params, isVarArg);
    359   LLVMContextImpl::FunctionTypeMap::iterator I =
    360     pImpl->FunctionTypes.find_as(Key);
    361   FunctionType *FT;
    362 
    363   if (I == pImpl->FunctionTypes.end()) {
    364     FT = (FunctionType*) pImpl->TypeAllocator.
    365       Allocate(sizeof(FunctionType) + sizeof(Type*) * (Params.size() + 1),
    366                AlignOf<FunctionType>::Alignment);
    367     new (FT) FunctionType(ReturnType, Params, isVarArg);
    368     pImpl->FunctionTypes[FT] = true;
    369   } else {
    370     FT = I->first;
    371   }
    372 
    373   return FT;
    374 }
    375 
    376 FunctionType *FunctionType::get(Type *Result, bool isVarArg) {
    377   return get(Result, None, isVarArg);
    378 }
    379 
    380 /// isValidReturnType - Return true if the specified type is valid as a return
    381 /// type.
    382 bool FunctionType::isValidReturnType(Type *RetTy) {
    383   return !RetTy->isFunctionTy() && !RetTy->isLabelTy() &&
    384   !RetTy->isMetadataTy();
    385 }
    386 
    387 /// isValidArgumentType - Return true if the specified type is valid as an
    388 /// argument type.
    389 bool FunctionType::isValidArgumentType(Type *ArgTy) {
    390   return ArgTy->isFirstClassType();
    391 }
    392 
    393 //===----------------------------------------------------------------------===//
    394 //                       StructType Implementation
    395 //===----------------------------------------------------------------------===//
    396 
    397 // Primitive Constructors.
    398 
    399 StructType *StructType::get(LLVMContext &Context, ArrayRef<Type*> ETypes,
    400                             bool isPacked) {
    401   LLVMContextImpl *pImpl = Context.pImpl;
    402   AnonStructTypeKeyInfo::KeyTy Key(ETypes, isPacked);
    403   LLVMContextImpl::StructTypeMap::iterator I =
    404     pImpl->AnonStructTypes.find_as(Key);
    405   StructType *ST;
    406 
    407   if (I == pImpl->AnonStructTypes.end()) {
    408     // Value not found.  Create a new type!
    409     ST = new (Context.pImpl->TypeAllocator) StructType(Context);
    410     ST->setSubclassData(SCDB_IsLiteral);  // Literal struct.
    411     ST->setBody(ETypes, isPacked);
    412     Context.pImpl->AnonStructTypes[ST] = true;
    413   } else {
    414     ST = I->first;
    415   }
    416 
    417   return ST;
    418 }
    419 
    420 void StructType::setBody(ArrayRef<Type*> Elements, bool isPacked) {
    421   assert(isOpaque() && "Struct body already set!");
    422 
    423   setSubclassData(getSubclassData() | SCDB_HasBody);
    424   if (isPacked)
    425     setSubclassData(getSubclassData() | SCDB_Packed);
    426 
    427   unsigned NumElements = Elements.size();
    428   Type **Elts = getContext().pImpl->TypeAllocator.Allocate<Type*>(NumElements);
    429   memcpy(Elts, Elements.data(), sizeof(Elements[0]) * NumElements);
    430 
    431   ContainedTys = Elts;
    432   NumContainedTys = NumElements;
    433 }
    434 
    435 void StructType::setName(StringRef Name) {
    436   if (Name == getName()) return;
    437 
    438   StringMap<StructType *> &SymbolTable = getContext().pImpl->NamedStructTypes;
    439   typedef StringMap<StructType *>::MapEntryTy EntryTy;
    440 
    441   // If this struct already had a name, remove its symbol table entry. Don't
    442   // delete the data yet because it may be part of the new name.
    443   if (SymbolTableEntry)
    444     SymbolTable.remove((EntryTy *)SymbolTableEntry);
    445 
    446   // If this is just removing the name, we're done.
    447   if (Name.empty()) {
    448     if (SymbolTableEntry) {
    449       // Delete the old string data.
    450       ((EntryTy *)SymbolTableEntry)->Destroy(SymbolTable.getAllocator());
    451       SymbolTableEntry = nullptr;
    452     }
    453     return;
    454   }
    455 
    456   // Look up the entry for the name.
    457   EntryTy *Entry = &getContext().pImpl->NamedStructTypes.GetOrCreateValue(Name);
    458 
    459   // While we have a name collision, try a random rename.
    460   if (Entry->getValue()) {
    461     SmallString<64> TempStr(Name);
    462     TempStr.push_back('.');
    463     raw_svector_ostream TmpStream(TempStr);
    464     unsigned NameSize = Name.size();
    465 
    466     do {
    467       TempStr.resize(NameSize + 1);
    468       TmpStream.resync();
    469       TmpStream << getContext().pImpl->NamedStructTypesUniqueID++;
    470 
    471       Entry = &getContext().pImpl->
    472                  NamedStructTypes.GetOrCreateValue(TmpStream.str());
    473     } while (Entry->getValue());
    474   }
    475 
    476   // Okay, we found an entry that isn't used.  It's us!
    477   Entry->setValue(this);
    478 
    479   // Delete the old string data.
    480   if (SymbolTableEntry)
    481     ((EntryTy *)SymbolTableEntry)->Destroy(SymbolTable.getAllocator());
    482   SymbolTableEntry = Entry;
    483 }
    484 
    485 //===----------------------------------------------------------------------===//
    486 // StructType Helper functions.
    487 
    488 StructType *StructType::create(LLVMContext &Context, StringRef Name) {
    489   StructType *ST = new (Context.pImpl->TypeAllocator) StructType(Context);
    490   if (!Name.empty())
    491     ST->setName(Name);
    492   return ST;
    493 }
    494 
    495 StructType *StructType::get(LLVMContext &Context, bool isPacked) {
    496   return get(Context, None, isPacked);
    497 }
    498 
    499 StructType *StructType::get(Type *type, ...) {
    500   assert(type && "Cannot create a struct type with no elements with this");
    501   LLVMContext &Ctx = type->getContext();
    502   va_list ap;
    503   SmallVector<llvm::Type*, 8> StructFields;
    504   va_start(ap, type);
    505   while (type) {
    506     StructFields.push_back(type);
    507     type = va_arg(ap, llvm::Type*);
    508   }
    509   return llvm::StructType::get(Ctx, StructFields);
    510 }
    511 
    512 StructType *StructType::create(LLVMContext &Context, ArrayRef<Type*> Elements,
    513                                StringRef Name, bool isPacked) {
    514   StructType *ST = create(Context, Name);
    515   ST->setBody(Elements, isPacked);
    516   return ST;
    517 }
    518 
    519 StructType *StructType::create(LLVMContext &Context, ArrayRef<Type*> Elements) {
    520   return create(Context, Elements, StringRef());
    521 }
    522 
    523 StructType *StructType::create(LLVMContext &Context) {
    524   return create(Context, StringRef());
    525 }
    526 
    527 StructType *StructType::create(ArrayRef<Type*> Elements, StringRef Name,
    528                                bool isPacked) {
    529   assert(!Elements.empty() &&
    530          "This method may not be invoked with an empty list");
    531   return create(Elements[0]->getContext(), Elements, Name, isPacked);
    532 }
    533 
    534 StructType *StructType::create(ArrayRef<Type*> Elements) {
    535   assert(!Elements.empty() &&
    536          "This method may not be invoked with an empty list");
    537   return create(Elements[0]->getContext(), Elements, StringRef());
    538 }
    539 
    540 StructType *StructType::create(StringRef Name, Type *type, ...) {
    541   assert(type && "Cannot create a struct type with no elements with this");
    542   LLVMContext &Ctx = type->getContext();
    543   va_list ap;
    544   SmallVector<llvm::Type*, 8> StructFields;
    545   va_start(ap, type);
    546   while (type) {
    547     StructFields.push_back(type);
    548     type = va_arg(ap, llvm::Type*);
    549   }
    550   return llvm::StructType::create(Ctx, StructFields, Name);
    551 }
    552 
    553 bool StructType::isSized(SmallPtrSet<const Type*, 4> *Visited) const {
    554   if ((getSubclassData() & SCDB_IsSized) != 0)
    555     return true;
    556   if (isOpaque())
    557     return false;
    558 
    559   if (Visited && !Visited->insert(this))
    560     return false;
    561 
    562   // Okay, our struct is sized if all of the elements are, but if one of the
    563   // elements is opaque, the struct isn't sized *yet*, but may become sized in
    564   // the future, so just bail out without caching.
    565   for (element_iterator I = element_begin(), E = element_end(); I != E; ++I)
    566     if (!(*I)->isSized(Visited))
    567       return false;
    568 
    569   // Here we cheat a bit and cast away const-ness. The goal is to memoize when
    570   // we find a sized type, as types can only move from opaque to sized, not the
    571   // other way.
    572   const_cast<StructType*>(this)->setSubclassData(
    573     getSubclassData() | SCDB_IsSized);
    574   return true;
    575 }
    576 
    577 StringRef StructType::getName() const {
    578   assert(!isLiteral() && "Literal structs never have names");
    579   if (!SymbolTableEntry) return StringRef();
    580 
    581   return ((StringMapEntry<StructType*> *)SymbolTableEntry)->getKey();
    582 }
    583 
    584 void StructType::setBody(Type *type, ...) {
    585   assert(type && "Cannot create a struct type with no elements with this");
    586   va_list ap;
    587   SmallVector<llvm::Type*, 8> StructFields;
    588   va_start(ap, type);
    589   while (type) {
    590     StructFields.push_back(type);
    591     type = va_arg(ap, llvm::Type*);
    592   }
    593   setBody(StructFields);
    594 }
    595 
    596 bool StructType::isValidElementType(Type *ElemTy) {
    597   return !ElemTy->isVoidTy() && !ElemTy->isLabelTy() &&
    598          !ElemTy->isMetadataTy() && !ElemTy->isFunctionTy();
    599 }
    600 
    601 /// isLayoutIdentical - Return true if this is layout identical to the
    602 /// specified struct.
    603 bool StructType::isLayoutIdentical(StructType *Other) const {
    604   if (this == Other) return true;
    605 
    606   if (isPacked() != Other->isPacked() ||
    607       getNumElements() != Other->getNumElements())
    608     return false;
    609 
    610   return std::equal(element_begin(), element_end(), Other->element_begin());
    611 }
    612 
    613 /// getTypeByName - Return the type with the specified name, or null if there
    614 /// is none by that name.
    615 StructType *Module::getTypeByName(StringRef Name) const {
    616   return getContext().pImpl->NamedStructTypes.lookup(Name);
    617 }
    618 
    619 
    620 //===----------------------------------------------------------------------===//
    621 //                       CompositeType Implementation
    622 //===----------------------------------------------------------------------===//
    623 
    624 Type *CompositeType::getTypeAtIndex(const Value *V) {
    625   if (StructType *STy = dyn_cast<StructType>(this)) {
    626     unsigned Idx =
    627       (unsigned)cast<Constant>(V)->getUniqueInteger().getZExtValue();
    628     assert(indexValid(Idx) && "Invalid structure index!");
    629     return STy->getElementType(Idx);
    630   }
    631 
    632   return cast<SequentialType>(this)->getElementType();
    633 }
    634 Type *CompositeType::getTypeAtIndex(unsigned Idx) {
    635   if (StructType *STy = dyn_cast<StructType>(this)) {
    636     assert(indexValid(Idx) && "Invalid structure index!");
    637     return STy->getElementType(Idx);
    638   }
    639 
    640   return cast<SequentialType>(this)->getElementType();
    641 }
    642 bool CompositeType::indexValid(const Value *V) const {
    643   if (const StructType *STy = dyn_cast<StructType>(this)) {
    644     // Structure indexes require (vectors of) 32-bit integer constants.  In the
    645     // vector case all of the indices must be equal.
    646     if (!V->getType()->getScalarType()->isIntegerTy(32))
    647       return false;
    648     const Constant *C = dyn_cast<Constant>(V);
    649     if (C && V->getType()->isVectorTy())
    650       C = C->getSplatValue();
    651     const ConstantInt *CU = dyn_cast_or_null<ConstantInt>(C);
    652     return CU && CU->getZExtValue() < STy->getNumElements();
    653   }
    654 
    655   // Sequential types can be indexed by any integer.
    656   return V->getType()->isIntOrIntVectorTy();
    657 }
    658 
    659 bool CompositeType::indexValid(unsigned Idx) const {
    660   if (const StructType *STy = dyn_cast<StructType>(this))
    661     return Idx < STy->getNumElements();
    662   // Sequential types can be indexed by any integer.
    663   return true;
    664 }
    665 
    666 
    667 //===----------------------------------------------------------------------===//
    668 //                           ArrayType Implementation
    669 //===----------------------------------------------------------------------===//
    670 
    671 ArrayType::ArrayType(Type *ElType, uint64_t NumEl)
    672   : SequentialType(ArrayTyID, ElType) {
    673   NumElements = NumEl;
    674 }
    675 
    676 ArrayType *ArrayType::get(Type *elementType, uint64_t NumElements) {
    677   Type *ElementType = const_cast<Type*>(elementType);
    678   assert(isValidElementType(ElementType) && "Invalid type for array element!");
    679 
    680   LLVMContextImpl *pImpl = ElementType->getContext().pImpl;
    681   ArrayType *&Entry =
    682     pImpl->ArrayTypes[std::make_pair(ElementType, NumElements)];
    683 
    684   if (!Entry)
    685     Entry = new (pImpl->TypeAllocator) ArrayType(ElementType, NumElements);
    686   return Entry;
    687 }
    688 
    689 bool ArrayType::isValidElementType(Type *ElemTy) {
    690   return !ElemTy->isVoidTy() && !ElemTy->isLabelTy() &&
    691          !ElemTy->isMetadataTy() && !ElemTy->isFunctionTy();
    692 }
    693 
    694 //===----------------------------------------------------------------------===//
    695 //                          VectorType Implementation
    696 //===----------------------------------------------------------------------===//
    697 
    698 VectorType::VectorType(Type *ElType, unsigned NumEl)
    699   : SequentialType(VectorTyID, ElType) {
    700   NumElements = NumEl;
    701 }
    702 
    703 VectorType *VectorType::get(Type *elementType, unsigned NumElements) {
    704   Type *ElementType = const_cast<Type*>(elementType);
    705   assert(NumElements > 0 && "#Elements of a VectorType must be greater than 0");
    706   assert(isValidElementType(ElementType) &&
    707          "Elements of a VectorType must be a primitive type");
    708 
    709   LLVMContextImpl *pImpl = ElementType->getContext().pImpl;
    710   VectorType *&Entry = ElementType->getContext().pImpl
    711     ->VectorTypes[std::make_pair(ElementType, NumElements)];
    712 
    713   if (!Entry)
    714     Entry = new (pImpl->TypeAllocator) VectorType(ElementType, NumElements);
    715   return Entry;
    716 }
    717 
    718 bool VectorType::isValidElementType(Type *ElemTy) {
    719   return ElemTy->isIntegerTy() || ElemTy->isFloatingPointTy() ||
    720     ElemTy->isPointerTy();
    721 }
    722 
    723 //===----------------------------------------------------------------------===//
    724 //                         PointerType Implementation
    725 //===----------------------------------------------------------------------===//
    726 
    727 PointerType *PointerType::get(Type *EltTy, unsigned AddressSpace) {
    728   assert(EltTy && "Can't get a pointer to <null> type!");
    729   assert(isValidElementType(EltTy) && "Invalid type for pointer element!");
    730 
    731   LLVMContextImpl *CImpl = EltTy->getContext().pImpl;
    732 
    733   // Since AddressSpace #0 is the common case, we special case it.
    734   PointerType *&Entry = AddressSpace == 0 ? CImpl->PointerTypes[EltTy]
    735      : CImpl->ASPointerTypes[std::make_pair(EltTy, AddressSpace)];
    736 
    737   if (!Entry)
    738     Entry = new (CImpl->TypeAllocator) PointerType(EltTy, AddressSpace);
    739   return Entry;
    740 }
    741 
    742 
    743 PointerType::PointerType(Type *E, unsigned AddrSpace)
    744   : SequentialType(PointerTyID, E) {
    745 #ifndef NDEBUG
    746   const unsigned oldNCT = NumContainedTys;
    747 #endif
    748   setSubclassData(AddrSpace);
    749   // Check for miscompile. PR11652.
    750   assert(oldNCT == NumContainedTys && "bitfield written out of bounds?");
    751 }
    752 
    753 PointerType *Type::getPointerTo(unsigned addrs) {
    754   return PointerType::get(this, addrs);
    755 }
    756 
    757 bool PointerType::isValidElementType(Type *ElemTy) {
    758   return !ElemTy->isVoidTy() && !ElemTy->isLabelTy() &&
    759          !ElemTy->isMetadataTy();
    760 }
    761