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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 0;
     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() {
    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() const {
    159   if (this->isIntegerTy())
    160     return true;
    161 
    162   if (const ArrayType *ATy = dyn_cast<ArrayType>(this))
    163     return ATy->getElementType()->isSized();
    164 
    165   if (const VectorType *VTy = dyn_cast<VectorType>(this))
    166     return VTy->getElementType()->isSized();
    167 
    168   if (!this->isStructTy())
    169     return false;
    170 
    171   return cast<StructType>(this)->isSized();
    172 }
    173 
    174 //===----------------------------------------------------------------------===//
    175 //                         Subclass Helper Methods
    176 //===----------------------------------------------------------------------===//
    177 
    178 unsigned Type::getIntegerBitWidth() const {
    179   return cast<IntegerType>(this)->getBitWidth();
    180 }
    181 
    182 bool Type::isFunctionVarArg() const {
    183   return cast<FunctionType>(this)->isVarArg();
    184 }
    185 
    186 Type *Type::getFunctionParamType(unsigned i) const {
    187   return cast<FunctionType>(this)->getParamType(i);
    188 }
    189 
    190 unsigned Type::getFunctionNumParams() const {
    191   return cast<FunctionType>(this)->getNumParams();
    192 }
    193 
    194 StringRef Type::getStructName() const {
    195   return cast<StructType>(this)->getName();
    196 }
    197 
    198 unsigned Type::getStructNumElements() const {
    199   return cast<StructType>(this)->getNumElements();
    200 }
    201 
    202 Type *Type::getStructElementType(unsigned N) const {
    203   return cast<StructType>(this)->getElementType(N);
    204 }
    205 
    206 Type *Type::getSequentialElementType() const {
    207   return cast<SequentialType>(this)->getElementType();
    208 }
    209 
    210 uint64_t Type::getArrayNumElements() const {
    211   return cast<ArrayType>(this)->getNumElements();
    212 }
    213 
    214 unsigned Type::getVectorNumElements() const {
    215   return cast<VectorType>(this)->getNumElements();
    216 }
    217 
    218 unsigned Type::getPointerAddressSpace() const {
    219   return cast<PointerType>(getScalarType())->getAddressSpace();
    220 }
    221 
    222 
    223 //===----------------------------------------------------------------------===//
    224 //                          Primitive 'Type' data
    225 //===----------------------------------------------------------------------===//
    226 
    227 Type *Type::getVoidTy(LLVMContext &C) { return &C.pImpl->VoidTy; }
    228 Type *Type::getLabelTy(LLVMContext &C) { return &C.pImpl->LabelTy; }
    229 Type *Type::getHalfTy(LLVMContext &C) { return &C.pImpl->HalfTy; }
    230 Type *Type::getFloatTy(LLVMContext &C) { return &C.pImpl->FloatTy; }
    231 Type *Type::getDoubleTy(LLVMContext &C) { return &C.pImpl->DoubleTy; }
    232 Type *Type::getMetadataTy(LLVMContext &C) { return &C.pImpl->MetadataTy; }
    233 Type *Type::getX86_FP80Ty(LLVMContext &C) { return &C.pImpl->X86_FP80Ty; }
    234 Type *Type::getFP128Ty(LLVMContext &C) { return &C.pImpl->FP128Ty; }
    235 Type *Type::getPPC_FP128Ty(LLVMContext &C) { return &C.pImpl->PPC_FP128Ty; }
    236 Type *Type::getX86_MMXTy(LLVMContext &C) { return &C.pImpl->X86_MMXTy; }
    237 
    238 IntegerType *Type::getInt1Ty(LLVMContext &C) { return &C.pImpl->Int1Ty; }
    239 IntegerType *Type::getInt8Ty(LLVMContext &C) { return &C.pImpl->Int8Ty; }
    240 IntegerType *Type::getInt16Ty(LLVMContext &C) { return &C.pImpl->Int16Ty; }
    241 IntegerType *Type::getInt32Ty(LLVMContext &C) { return &C.pImpl->Int32Ty; }
    242 IntegerType *Type::getInt64Ty(LLVMContext &C) { return &C.pImpl->Int64Ty; }
    243 
    244 IntegerType *Type::getIntNTy(LLVMContext &C, unsigned N) {
    245   return IntegerType::get(C, N);
    246 }
    247 
    248 PointerType *Type::getHalfPtrTy(LLVMContext &C, unsigned AS) {
    249   return getHalfTy(C)->getPointerTo(AS);
    250 }
    251 
    252 PointerType *Type::getFloatPtrTy(LLVMContext &C, unsigned AS) {
    253   return getFloatTy(C)->getPointerTo(AS);
    254 }
    255 
    256 PointerType *Type::getDoublePtrTy(LLVMContext &C, unsigned AS) {
    257   return getDoubleTy(C)->getPointerTo(AS);
    258 }
    259 
    260 PointerType *Type::getX86_FP80PtrTy(LLVMContext &C, unsigned AS) {
    261   return getX86_FP80Ty(C)->getPointerTo(AS);
    262 }
    263 
    264 PointerType *Type::getFP128PtrTy(LLVMContext &C, unsigned AS) {
    265   return getFP128Ty(C)->getPointerTo(AS);
    266 }
    267 
    268 PointerType *Type::getPPC_FP128PtrTy(LLVMContext &C, unsigned AS) {
    269   return getPPC_FP128Ty(C)->getPointerTo(AS);
    270 }
    271 
    272 PointerType *Type::getX86_MMXPtrTy(LLVMContext &C, unsigned AS) {
    273   return getX86_MMXTy(C)->getPointerTo(AS);
    274 }
    275 
    276 PointerType *Type::getIntNPtrTy(LLVMContext &C, unsigned N, unsigned AS) {
    277   return getIntNTy(C, N)->getPointerTo(AS);
    278 }
    279 
    280 PointerType *Type::getInt1PtrTy(LLVMContext &C, unsigned AS) {
    281   return getInt1Ty(C)->getPointerTo(AS);
    282 }
    283 
    284 PointerType *Type::getInt8PtrTy(LLVMContext &C, unsigned AS) {
    285   return getInt8Ty(C)->getPointerTo(AS);
    286 }
    287 
    288 PointerType *Type::getInt16PtrTy(LLVMContext &C, unsigned AS) {
    289   return getInt16Ty(C)->getPointerTo(AS);
    290 }
    291 
    292 PointerType *Type::getInt32PtrTy(LLVMContext &C, unsigned AS) {
    293   return getInt32Ty(C)->getPointerTo(AS);
    294 }
    295 
    296 PointerType *Type::getInt64PtrTy(LLVMContext &C, unsigned AS) {
    297   return getInt64Ty(C)->getPointerTo(AS);
    298 }
    299 
    300 
    301 //===----------------------------------------------------------------------===//
    302 //                       IntegerType Implementation
    303 //===----------------------------------------------------------------------===//
    304 
    305 IntegerType *IntegerType::get(LLVMContext &C, unsigned NumBits) {
    306   assert(NumBits >= MIN_INT_BITS && "bitwidth too small");
    307   assert(NumBits <= MAX_INT_BITS && "bitwidth too large");
    308 
    309   // Check for the built-in integer types
    310   switch (NumBits) {
    311   case  1: return cast<IntegerType>(Type::getInt1Ty(C));
    312   case  8: return cast<IntegerType>(Type::getInt8Ty(C));
    313   case 16: return cast<IntegerType>(Type::getInt16Ty(C));
    314   case 32: return cast<IntegerType>(Type::getInt32Ty(C));
    315   case 64: return cast<IntegerType>(Type::getInt64Ty(C));
    316   default:
    317     break;
    318   }
    319 
    320   IntegerType *&Entry = C.pImpl->IntegerTypes[NumBits];
    321 
    322   if (Entry == 0)
    323     Entry = new (C.pImpl->TypeAllocator) IntegerType(C, NumBits);
    324 
    325   return Entry;
    326 }
    327 
    328 bool IntegerType::isPowerOf2ByteWidth() const {
    329   unsigned BitWidth = getBitWidth();
    330   return (BitWidth > 7) && isPowerOf2_32(BitWidth);
    331 }
    332 
    333 APInt IntegerType::getMask() const {
    334   return APInt::getAllOnesValue(getBitWidth());
    335 }
    336 
    337 //===----------------------------------------------------------------------===//
    338 //                       FunctionType Implementation
    339 //===----------------------------------------------------------------------===//
    340 
    341 FunctionType::FunctionType(Type *Result, ArrayRef<Type*> Params,
    342                            bool IsVarArgs)
    343   : Type(Result->getContext(), FunctionTyID) {
    344   Type **SubTys = reinterpret_cast<Type**>(this+1);
    345   assert(isValidReturnType(Result) && "invalid return type for function");
    346   setSubclassData(IsVarArgs);
    347 
    348   SubTys[0] = const_cast<Type*>(Result);
    349 
    350   for (unsigned i = 0, e = Params.size(); i != e; ++i) {
    351     assert(isValidArgumentType(Params[i]) &&
    352            "Not a valid type for function argument!");
    353     SubTys[i+1] = Params[i];
    354   }
    355 
    356   ContainedTys = SubTys;
    357   NumContainedTys = Params.size() + 1; // + 1 for result type
    358 }
    359 
    360 // FunctionType::get - The factory function for the FunctionType class.
    361 FunctionType *FunctionType::get(Type *ReturnType,
    362                                 ArrayRef<Type*> Params, bool isVarArg) {
    363   LLVMContextImpl *pImpl = ReturnType->getContext().pImpl;
    364   FunctionTypeKeyInfo::KeyTy Key(ReturnType, Params, isVarArg);
    365   LLVMContextImpl::FunctionTypeMap::iterator I =
    366     pImpl->FunctionTypes.find_as(Key);
    367   FunctionType *FT;
    368 
    369   if (I == pImpl->FunctionTypes.end()) {
    370     FT = (FunctionType*) pImpl->TypeAllocator.
    371       Allocate(sizeof(FunctionType) + sizeof(Type*) * (Params.size() + 1),
    372                AlignOf<FunctionType>::Alignment);
    373     new (FT) FunctionType(ReturnType, Params, isVarArg);
    374     pImpl->FunctionTypes[FT] = true;
    375   } else {
    376     FT = I->first;
    377   }
    378 
    379   return FT;
    380 }
    381 
    382 FunctionType *FunctionType::get(Type *Result, bool isVarArg) {
    383   return get(Result, None, isVarArg);
    384 }
    385 
    386 /// isValidReturnType - Return true if the specified type is valid as a return
    387 /// type.
    388 bool FunctionType::isValidReturnType(Type *RetTy) {
    389   return !RetTy->isFunctionTy() && !RetTy->isLabelTy() &&
    390   !RetTy->isMetadataTy();
    391 }
    392 
    393 /// isValidArgumentType - Return true if the specified type is valid as an
    394 /// argument type.
    395 bool FunctionType::isValidArgumentType(Type *ArgTy) {
    396   return ArgTy->isFirstClassType();
    397 }
    398 
    399 //===----------------------------------------------------------------------===//
    400 //                       StructType Implementation
    401 //===----------------------------------------------------------------------===//
    402 
    403 // Primitive Constructors.
    404 
    405 StructType *StructType::get(LLVMContext &Context, ArrayRef<Type*> ETypes,
    406                             bool isPacked) {
    407   LLVMContextImpl *pImpl = Context.pImpl;
    408   AnonStructTypeKeyInfo::KeyTy Key(ETypes, isPacked);
    409   LLVMContextImpl::StructTypeMap::iterator I =
    410     pImpl->AnonStructTypes.find_as(Key);
    411   StructType *ST;
    412 
    413   if (I == pImpl->AnonStructTypes.end()) {
    414     // Value not found.  Create a new type!
    415     ST = new (Context.pImpl->TypeAllocator) StructType(Context);
    416     ST->setSubclassData(SCDB_IsLiteral);  // Literal struct.
    417     ST->setBody(ETypes, isPacked);
    418     Context.pImpl->AnonStructTypes[ST] = true;
    419   } else {
    420     ST = I->first;
    421   }
    422 
    423   return ST;
    424 }
    425 
    426 void StructType::setBody(ArrayRef<Type*> Elements, bool isPacked) {
    427   assert(isOpaque() && "Struct body already set!");
    428 
    429   setSubclassData(getSubclassData() | SCDB_HasBody);
    430   if (isPacked)
    431     setSubclassData(getSubclassData() | SCDB_Packed);
    432 
    433   unsigned NumElements = Elements.size();
    434   Type **Elts = getContext().pImpl->TypeAllocator.Allocate<Type*>(NumElements);
    435   memcpy(Elts, Elements.data(), sizeof(Elements[0]) * NumElements);
    436 
    437   ContainedTys = Elts;
    438   NumContainedTys = NumElements;
    439 }
    440 
    441 void StructType::setName(StringRef Name) {
    442   if (Name == getName()) return;
    443 
    444   StringMap<StructType *> &SymbolTable = getContext().pImpl->NamedStructTypes;
    445   typedef StringMap<StructType *>::MapEntryTy EntryTy;
    446 
    447   // If this struct already had a name, remove its symbol table entry. Don't
    448   // delete the data yet because it may be part of the new name.
    449   if (SymbolTableEntry)
    450     SymbolTable.remove((EntryTy *)SymbolTableEntry);
    451 
    452   // If this is just removing the name, we're done.
    453   if (Name.empty()) {
    454     if (SymbolTableEntry) {
    455       // Delete the old string data.
    456       ((EntryTy *)SymbolTableEntry)->Destroy(SymbolTable.getAllocator());
    457       SymbolTableEntry = 0;
    458     }
    459     return;
    460   }
    461 
    462   // Look up the entry for the name.
    463   EntryTy *Entry = &getContext().pImpl->NamedStructTypes.GetOrCreateValue(Name);
    464 
    465   // While we have a name collision, try a random rename.
    466   if (Entry->getValue()) {
    467     SmallString<64> TempStr(Name);
    468     TempStr.push_back('.');
    469     raw_svector_ostream TmpStream(TempStr);
    470     unsigned NameSize = Name.size();
    471 
    472     do {
    473       TempStr.resize(NameSize + 1);
    474       TmpStream.resync();
    475       TmpStream << getContext().pImpl->NamedStructTypesUniqueID++;
    476 
    477       Entry = &getContext().pImpl->
    478                  NamedStructTypes.GetOrCreateValue(TmpStream.str());
    479     } while (Entry->getValue());
    480   }
    481 
    482   // Okay, we found an entry that isn't used.  It's us!
    483   Entry->setValue(this);
    484 
    485   // Delete the old string data.
    486   if (SymbolTableEntry)
    487     ((EntryTy *)SymbolTableEntry)->Destroy(SymbolTable.getAllocator());
    488   SymbolTableEntry = Entry;
    489 }
    490 
    491 //===----------------------------------------------------------------------===//
    492 // StructType Helper functions.
    493 
    494 StructType *StructType::create(LLVMContext &Context, StringRef Name) {
    495   StructType *ST = new (Context.pImpl->TypeAllocator) StructType(Context);
    496   if (!Name.empty())
    497     ST->setName(Name);
    498   return ST;
    499 }
    500 
    501 StructType *StructType::get(LLVMContext &Context, bool isPacked) {
    502   return get(Context, None, isPacked);
    503 }
    504 
    505 StructType *StructType::get(Type *type, ...) {
    506   assert(type != 0 && "Cannot create a struct type with no elements with this");
    507   LLVMContext &Ctx = type->getContext();
    508   va_list ap;
    509   SmallVector<llvm::Type*, 8> StructFields;
    510   va_start(ap, type);
    511   while (type) {
    512     StructFields.push_back(type);
    513     type = va_arg(ap, llvm::Type*);
    514   }
    515   return llvm::StructType::get(Ctx, StructFields);
    516 }
    517 
    518 StructType *StructType::create(LLVMContext &Context, ArrayRef<Type*> Elements,
    519                                StringRef Name, bool isPacked) {
    520   StructType *ST = create(Context, Name);
    521   ST->setBody(Elements, isPacked);
    522   return ST;
    523 }
    524 
    525 StructType *StructType::create(LLVMContext &Context, ArrayRef<Type*> Elements) {
    526   return create(Context, Elements, StringRef());
    527 }
    528 
    529 StructType *StructType::create(LLVMContext &Context) {
    530   return create(Context, StringRef());
    531 }
    532 
    533 StructType *StructType::create(ArrayRef<Type*> Elements, StringRef Name,
    534                                bool isPacked) {
    535   assert(!Elements.empty() &&
    536          "This method may not be invoked with an empty list");
    537   return create(Elements[0]->getContext(), Elements, Name, isPacked);
    538 }
    539 
    540 StructType *StructType::create(ArrayRef<Type*> Elements) {
    541   assert(!Elements.empty() &&
    542          "This method may not be invoked with an empty list");
    543   return create(Elements[0]->getContext(), Elements, StringRef());
    544 }
    545 
    546 StructType *StructType::create(StringRef Name, Type *type, ...) {
    547   assert(type != 0 && "Cannot create a struct type with no elements with this");
    548   LLVMContext &Ctx = type->getContext();
    549   va_list ap;
    550   SmallVector<llvm::Type*, 8> StructFields;
    551   va_start(ap, type);
    552   while (type) {
    553     StructFields.push_back(type);
    554     type = va_arg(ap, llvm::Type*);
    555   }
    556   return llvm::StructType::create(Ctx, StructFields, Name);
    557 }
    558 
    559 bool StructType::isSized() const {
    560   if ((getSubclassData() & SCDB_IsSized) != 0)
    561     return true;
    562   if (isOpaque())
    563     return false;
    564 
    565   // Okay, our struct is sized if all of the elements are, but if one of the
    566   // elements is opaque, the struct isn't sized *yet*, but may become sized in
    567   // the future, so just bail out without caching.
    568   for (element_iterator I = element_begin(), E = element_end(); I != E; ++I)
    569     if (!(*I)->isSized())
    570       return false;
    571 
    572   // Here we cheat a bit and cast away const-ness. The goal is to memoize when
    573   // we find a sized type, as types can only move from opaque to sized, not the
    574   // other way.
    575   const_cast<StructType*>(this)->setSubclassData(
    576     getSubclassData() | SCDB_IsSized);
    577   return true;
    578 }
    579 
    580 StringRef StructType::getName() const {
    581   assert(!isLiteral() && "Literal structs never have names");
    582   if (SymbolTableEntry == 0) return StringRef();
    583 
    584   return ((StringMapEntry<StructType*> *)SymbolTableEntry)->getKey();
    585 }
    586 
    587 void StructType::setBody(Type *type, ...) {
    588   assert(type != 0 && "Cannot create a struct type with no elements with this");
    589   va_list ap;
    590   SmallVector<llvm::Type*, 8> StructFields;
    591   va_start(ap, type);
    592   while (type) {
    593     StructFields.push_back(type);
    594     type = va_arg(ap, llvm::Type*);
    595   }
    596   setBody(StructFields);
    597 }
    598 
    599 bool StructType::isValidElementType(Type *ElemTy) {
    600   return !ElemTy->isVoidTy() && !ElemTy->isLabelTy() &&
    601          !ElemTy->isMetadataTy() && !ElemTy->isFunctionTy();
    602 }
    603 
    604 /// isLayoutIdentical - Return true if this is layout identical to the
    605 /// specified struct.
    606 bool StructType::isLayoutIdentical(StructType *Other) const {
    607   if (this == Other) return true;
    608 
    609   if (isPacked() != Other->isPacked() ||
    610       getNumElements() != Other->getNumElements())
    611     return false;
    612 
    613   return std::equal(element_begin(), element_end(), Other->element_begin());
    614 }
    615 
    616 /// getTypeByName - Return the type with the specified name, or null if there
    617 /// is none by that name.
    618 StructType *Module::getTypeByName(StringRef Name) const {
    619   StringMap<StructType*>::iterator I =
    620     getContext().pImpl->NamedStructTypes.find(Name);
    621   if (I != getContext().pImpl->NamedStructTypes.end())
    622     return I->second;
    623   return 0;
    624 }
    625 
    626 
    627 //===----------------------------------------------------------------------===//
    628 //                       CompositeType Implementation
    629 //===----------------------------------------------------------------------===//
    630 
    631 Type *CompositeType::getTypeAtIndex(const Value *V) {
    632   if (StructType *STy = dyn_cast<StructType>(this)) {
    633     unsigned Idx =
    634       (unsigned)cast<Constant>(V)->getUniqueInteger().getZExtValue();
    635     assert(indexValid(Idx) && "Invalid structure index!");
    636     return STy->getElementType(Idx);
    637   }
    638 
    639   return cast<SequentialType>(this)->getElementType();
    640 }
    641 Type *CompositeType::getTypeAtIndex(unsigned Idx) {
    642   if (StructType *STy = dyn_cast<StructType>(this)) {
    643     assert(indexValid(Idx) && "Invalid structure index!");
    644     return STy->getElementType(Idx);
    645   }
    646 
    647   return cast<SequentialType>(this)->getElementType();
    648 }
    649 bool CompositeType::indexValid(const Value *V) const {
    650   if (const StructType *STy = dyn_cast<StructType>(this)) {
    651     // Structure indexes require (vectors of) 32-bit integer constants.  In the
    652     // vector case all of the indices must be equal.
    653     if (!V->getType()->getScalarType()->isIntegerTy(32))
    654       return false;
    655     const Constant *C = dyn_cast<Constant>(V);
    656     if (C && V->getType()->isVectorTy())
    657       C = C->getSplatValue();
    658     const ConstantInt *CU = dyn_cast_or_null<ConstantInt>(C);
    659     return CU && CU->getZExtValue() < STy->getNumElements();
    660   }
    661 
    662   // Sequential types can be indexed by any integer.
    663   return V->getType()->isIntOrIntVectorTy();
    664 }
    665 
    666 bool CompositeType::indexValid(unsigned Idx) const {
    667   if (const StructType *STy = dyn_cast<StructType>(this))
    668     return Idx < STy->getNumElements();
    669   // Sequential types can be indexed by any integer.
    670   return true;
    671 }
    672 
    673 
    674 //===----------------------------------------------------------------------===//
    675 //                           ArrayType Implementation
    676 //===----------------------------------------------------------------------===//
    677 
    678 ArrayType::ArrayType(Type *ElType, uint64_t NumEl)
    679   : SequentialType(ArrayTyID, ElType) {
    680   NumElements = NumEl;
    681 }
    682 
    683 ArrayType *ArrayType::get(Type *elementType, uint64_t NumElements) {
    684   Type *ElementType = const_cast<Type*>(elementType);
    685   assert(isValidElementType(ElementType) && "Invalid type for array element!");
    686 
    687   LLVMContextImpl *pImpl = ElementType->getContext().pImpl;
    688   ArrayType *&Entry =
    689     pImpl->ArrayTypes[std::make_pair(ElementType, NumElements)];
    690 
    691   if (Entry == 0)
    692     Entry = new (pImpl->TypeAllocator) ArrayType(ElementType, NumElements);
    693   return Entry;
    694 }
    695 
    696 bool ArrayType::isValidElementType(Type *ElemTy) {
    697   return !ElemTy->isVoidTy() && !ElemTy->isLabelTy() &&
    698          !ElemTy->isMetadataTy() && !ElemTy->isFunctionTy();
    699 }
    700 
    701 //===----------------------------------------------------------------------===//
    702 //                          VectorType Implementation
    703 //===----------------------------------------------------------------------===//
    704 
    705 VectorType::VectorType(Type *ElType, unsigned NumEl)
    706   : SequentialType(VectorTyID, ElType) {
    707   NumElements = NumEl;
    708 }
    709 
    710 VectorType *VectorType::get(Type *elementType, unsigned NumElements) {
    711   Type *ElementType = const_cast<Type*>(elementType);
    712   assert(NumElements > 0 && "#Elements of a VectorType must be greater than 0");
    713   assert(isValidElementType(ElementType) &&
    714          "Elements of a VectorType must be a primitive type");
    715 
    716   LLVMContextImpl *pImpl = ElementType->getContext().pImpl;
    717   VectorType *&Entry = ElementType->getContext().pImpl
    718     ->VectorTypes[std::make_pair(ElementType, NumElements)];
    719 
    720   if (Entry == 0)
    721     Entry = new (pImpl->TypeAllocator) VectorType(ElementType, NumElements);
    722   return Entry;
    723 }
    724 
    725 bool VectorType::isValidElementType(Type *ElemTy) {
    726   return ElemTy->isIntegerTy() || ElemTy->isFloatingPointTy() ||
    727     ElemTy->isPointerTy();
    728 }
    729 
    730 //===----------------------------------------------------------------------===//
    731 //                         PointerType Implementation
    732 //===----------------------------------------------------------------------===//
    733 
    734 PointerType *PointerType::get(Type *EltTy, unsigned AddressSpace) {
    735   assert(EltTy && "Can't get a pointer to <null> type!");
    736   assert(isValidElementType(EltTy) && "Invalid type for pointer element!");
    737 
    738   LLVMContextImpl *CImpl = EltTy->getContext().pImpl;
    739 
    740   // Since AddressSpace #0 is the common case, we special case it.
    741   PointerType *&Entry = AddressSpace == 0 ? CImpl->PointerTypes[EltTy]
    742      : CImpl->ASPointerTypes[std::make_pair(EltTy, AddressSpace)];
    743 
    744   if (Entry == 0)
    745     Entry = new (CImpl->TypeAllocator) PointerType(EltTy, AddressSpace);
    746   return Entry;
    747 }
    748 
    749 
    750 PointerType::PointerType(Type *E, unsigned AddrSpace)
    751   : SequentialType(PointerTyID, E) {
    752 #ifndef NDEBUG
    753   const unsigned oldNCT = NumContainedTys;
    754 #endif
    755   setSubclassData(AddrSpace);
    756   // Check for miscompile. PR11652.
    757   assert(oldNCT == NumContainedTys && "bitfield written out of bounds?");
    758 }
    759 
    760 PointerType *Type::getPointerTo(unsigned addrs) {
    761   return PointerType::get(this, addrs);
    762 }
    763 
    764 bool PointerType::isValidElementType(Type *ElemTy) {
    765   return !ElemTy->isVoidTy() && !ElemTy->isLabelTy() &&
    766          !ElemTy->isMetadataTy();
    767 }
    768