Home | History | Annotate | Download | only in IR
      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   case TokenTyID     : return getTokenTy(C);
     39   default:
     40     return nullptr;
     41   }
     42 }
     43 
     44 /// getScalarType - If this is a vector type, return the element type,
     45 /// otherwise return this.
     46 Type *Type::getScalarType() const {
     47   if (auto *VTy = dyn_cast<VectorType>(this))
     48     return VTy->getElementType();
     49   return const_cast<Type*>(this);
     50 }
     51 
     52 /// isIntegerTy - Return true if this is an IntegerType of the specified width.
     53 bool Type::isIntegerTy(unsigned Bitwidth) const {
     54   return isIntegerTy() && cast<IntegerType>(this)->getBitWidth() == Bitwidth;
     55 }
     56 
     57 // canLosslesslyBitCastTo - Return true if this type can be converted to
     58 // 'Ty' without any reinterpretation of bits.  For example, i8* to i32*.
     59 //
     60 bool Type::canLosslesslyBitCastTo(Type *Ty) const {
     61   // Identity cast means no change so return true
     62   if (this == Ty)
     63     return true;
     64 
     65   // They are not convertible unless they are at least first class types
     66   if (!this->isFirstClassType() || !Ty->isFirstClassType())
     67     return false;
     68 
     69   // Vector -> Vector conversions are always lossless if the two vector types
     70   // have the same size, otherwise not.  Also, 64-bit vector types can be
     71   // converted to x86mmx.
     72   if (auto *thisPTy = dyn_cast<VectorType>(this)) {
     73     if (auto *thatPTy = dyn_cast<VectorType>(Ty))
     74       return thisPTy->getBitWidth() == thatPTy->getBitWidth();
     75     if (Ty->getTypeID() == Type::X86_MMXTyID &&
     76         thisPTy->getBitWidth() == 64)
     77       return true;
     78   }
     79 
     80   if (this->getTypeID() == Type::X86_MMXTyID)
     81     if (auto *thatPTy = dyn_cast<VectorType>(Ty))
     82       if (thatPTy->getBitWidth() == 64)
     83         return true;
     84 
     85   // At this point we have only various mismatches of the first class types
     86   // remaining and ptr->ptr. Just select the lossless conversions. Everything
     87   // else is not lossless. Conservatively assume we can't losslessly convert
     88   // between pointers with different address spaces.
     89   if (auto *PTy = dyn_cast<PointerType>(this)) {
     90     if (auto *OtherPTy = dyn_cast<PointerType>(Ty))
     91       return PTy->getAddressSpace() == OtherPTy->getAddressSpace();
     92     return false;
     93   }
     94   return false;  // Other types have no identity values
     95 }
     96 
     97 bool Type::isEmptyTy() const {
     98   if (auto *ATy = dyn_cast<ArrayType>(this)) {
     99     unsigned NumElements = ATy->getNumElements();
    100     return NumElements == 0 || ATy->getElementType()->isEmptyTy();
    101   }
    102 
    103   if (auto *STy = dyn_cast<StructType>(this)) {
    104     unsigned NumElements = STy->getNumElements();
    105     for (unsigned i = 0; i < NumElements; ++i)
    106       if (!STy->getElementType(i)->isEmptyTy())
    107         return false;
    108     return true;
    109   }
    110 
    111   return false;
    112 }
    113 
    114 unsigned Type::getPrimitiveSizeInBits() const {
    115   switch (getTypeID()) {
    116   case Type::HalfTyID: return 16;
    117   case Type::FloatTyID: return 32;
    118   case Type::DoubleTyID: return 64;
    119   case Type::X86_FP80TyID: return 80;
    120   case Type::FP128TyID: return 128;
    121   case Type::PPC_FP128TyID: return 128;
    122   case Type::X86_MMXTyID: return 64;
    123   case Type::IntegerTyID: return cast<IntegerType>(this)->getBitWidth();
    124   case Type::VectorTyID:  return cast<VectorType>(this)->getBitWidth();
    125   default: return 0;
    126   }
    127 }
    128 
    129 /// getScalarSizeInBits - If this is a vector type, return the
    130 /// getPrimitiveSizeInBits value for the element type. Otherwise return the
    131 /// getPrimitiveSizeInBits value for this type.
    132 unsigned Type::getScalarSizeInBits() const {
    133   return getScalarType()->getPrimitiveSizeInBits();
    134 }
    135 
    136 /// getFPMantissaWidth - Return the width of the mantissa of this type.  This
    137 /// is only valid on floating point types.  If the FP type does not
    138 /// have a stable mantissa (e.g. ppc long double), this method returns -1.
    139 int Type::getFPMantissaWidth() const {
    140   if (auto *VTy = dyn_cast<VectorType>(this))
    141     return VTy->getElementType()->getFPMantissaWidth();
    142   assert(isFloatingPointTy() && "Not a floating point type!");
    143   if (getTypeID() == HalfTyID) return 11;
    144   if (getTypeID() == FloatTyID) return 24;
    145   if (getTypeID() == DoubleTyID) return 53;
    146   if (getTypeID() == X86_FP80TyID) return 64;
    147   if (getTypeID() == FP128TyID) return 113;
    148   assert(getTypeID() == PPC_FP128TyID && "unknown fp type");
    149   return -1;
    150 }
    151 
    152 /// isSizedDerivedType - Derived types like structures and arrays are sized
    153 /// iff all of the members of the type are sized as well.  Since asking for
    154 /// their size is relatively uncommon, move this operation out of line.
    155 bool Type::isSizedDerivedType(SmallPtrSetImpl<Type*> *Visited) const {
    156   if (auto *ATy = dyn_cast<ArrayType>(this))
    157     return ATy->getElementType()->isSized(Visited);
    158 
    159   if (auto *VTy = dyn_cast<VectorType>(this))
    160     return VTy->getElementType()->isSized(Visited);
    161 
    162   return cast<StructType>(this)->isSized(Visited);
    163 }
    164 
    165 //===----------------------------------------------------------------------===//
    166 //                         Subclass Helper Methods
    167 //===----------------------------------------------------------------------===//
    168 
    169 unsigned Type::getIntegerBitWidth() const {
    170   return cast<IntegerType>(this)->getBitWidth();
    171 }
    172 
    173 bool Type::isFunctionVarArg() const {
    174   return cast<FunctionType>(this)->isVarArg();
    175 }
    176 
    177 Type *Type::getFunctionParamType(unsigned i) const {
    178   return cast<FunctionType>(this)->getParamType(i);
    179 }
    180 
    181 unsigned Type::getFunctionNumParams() const {
    182   return cast<FunctionType>(this)->getNumParams();
    183 }
    184 
    185 StringRef Type::getStructName() const {
    186   return cast<StructType>(this)->getName();
    187 }
    188 
    189 unsigned Type::getStructNumElements() const {
    190   return cast<StructType>(this)->getNumElements();
    191 }
    192 
    193 Type *Type::getStructElementType(unsigned N) const {
    194   return cast<StructType>(this)->getElementType(N);
    195 }
    196 
    197 Type *Type::getSequentialElementType() const {
    198   return cast<SequentialType>(this)->getElementType();
    199 }
    200 
    201 uint64_t Type::getArrayNumElements() const {
    202   return cast<ArrayType>(this)->getNumElements();
    203 }
    204 
    205 unsigned Type::getVectorNumElements() const {
    206   return cast<VectorType>(this)->getNumElements();
    207 }
    208 
    209 unsigned Type::getPointerAddressSpace() const {
    210   return cast<PointerType>(getScalarType())->getAddressSpace();
    211 }
    212 
    213 
    214 //===----------------------------------------------------------------------===//
    215 //                          Primitive 'Type' data
    216 //===----------------------------------------------------------------------===//
    217 
    218 Type *Type::getVoidTy(LLVMContext &C) { return &C.pImpl->VoidTy; }
    219 Type *Type::getLabelTy(LLVMContext &C) { return &C.pImpl->LabelTy; }
    220 Type *Type::getHalfTy(LLVMContext &C) { return &C.pImpl->HalfTy; }
    221 Type *Type::getFloatTy(LLVMContext &C) { return &C.pImpl->FloatTy; }
    222 Type *Type::getDoubleTy(LLVMContext &C) { return &C.pImpl->DoubleTy; }
    223 Type *Type::getMetadataTy(LLVMContext &C) { return &C.pImpl->MetadataTy; }
    224 Type *Type::getTokenTy(LLVMContext &C) { return &C.pImpl->TokenTy; }
    225 Type *Type::getX86_FP80Ty(LLVMContext &C) { return &C.pImpl->X86_FP80Ty; }
    226 Type *Type::getFP128Ty(LLVMContext &C) { return &C.pImpl->FP128Ty; }
    227 Type *Type::getPPC_FP128Ty(LLVMContext &C) { return &C.pImpl->PPC_FP128Ty; }
    228 Type *Type::getX86_MMXTy(LLVMContext &C) { return &C.pImpl->X86_MMXTy; }
    229 
    230 IntegerType *Type::getInt1Ty(LLVMContext &C) { return &C.pImpl->Int1Ty; }
    231 IntegerType *Type::getInt8Ty(LLVMContext &C) { return &C.pImpl->Int8Ty; }
    232 IntegerType *Type::getInt16Ty(LLVMContext &C) { return &C.pImpl->Int16Ty; }
    233 IntegerType *Type::getInt32Ty(LLVMContext &C) { return &C.pImpl->Int32Ty; }
    234 IntegerType *Type::getInt64Ty(LLVMContext &C) { return &C.pImpl->Int64Ty; }
    235 IntegerType *Type::getInt128Ty(LLVMContext &C) { return &C.pImpl->Int128Ty; }
    236 
    237 IntegerType *Type::getIntNTy(LLVMContext &C, unsigned N) {
    238   return IntegerType::get(C, N);
    239 }
    240 
    241 PointerType *Type::getHalfPtrTy(LLVMContext &C, unsigned AS) {
    242   return getHalfTy(C)->getPointerTo(AS);
    243 }
    244 
    245 PointerType *Type::getFloatPtrTy(LLVMContext &C, unsigned AS) {
    246   return getFloatTy(C)->getPointerTo(AS);
    247 }
    248 
    249 PointerType *Type::getDoublePtrTy(LLVMContext &C, unsigned AS) {
    250   return getDoubleTy(C)->getPointerTo(AS);
    251 }
    252 
    253 PointerType *Type::getX86_FP80PtrTy(LLVMContext &C, unsigned AS) {
    254   return getX86_FP80Ty(C)->getPointerTo(AS);
    255 }
    256 
    257 PointerType *Type::getFP128PtrTy(LLVMContext &C, unsigned AS) {
    258   return getFP128Ty(C)->getPointerTo(AS);
    259 }
    260 
    261 PointerType *Type::getPPC_FP128PtrTy(LLVMContext &C, unsigned AS) {
    262   return getPPC_FP128Ty(C)->getPointerTo(AS);
    263 }
    264 
    265 PointerType *Type::getX86_MMXPtrTy(LLVMContext &C, unsigned AS) {
    266   return getX86_MMXTy(C)->getPointerTo(AS);
    267 }
    268 
    269 PointerType *Type::getIntNPtrTy(LLVMContext &C, unsigned N, unsigned AS) {
    270   return getIntNTy(C, N)->getPointerTo(AS);
    271 }
    272 
    273 PointerType *Type::getInt1PtrTy(LLVMContext &C, unsigned AS) {
    274   return getInt1Ty(C)->getPointerTo(AS);
    275 }
    276 
    277 PointerType *Type::getInt8PtrTy(LLVMContext &C, unsigned AS) {
    278   return getInt8Ty(C)->getPointerTo(AS);
    279 }
    280 
    281 PointerType *Type::getInt16PtrTy(LLVMContext &C, unsigned AS) {
    282   return getInt16Ty(C)->getPointerTo(AS);
    283 }
    284 
    285 PointerType *Type::getInt32PtrTy(LLVMContext &C, unsigned AS) {
    286   return getInt32Ty(C)->getPointerTo(AS);
    287 }
    288 
    289 PointerType *Type::getInt64PtrTy(LLVMContext &C, unsigned AS) {
    290   return getInt64Ty(C)->getPointerTo(AS);
    291 }
    292 
    293 
    294 //===----------------------------------------------------------------------===//
    295 //                       IntegerType Implementation
    296 //===----------------------------------------------------------------------===//
    297 
    298 IntegerType *IntegerType::get(LLVMContext &C, unsigned NumBits) {
    299   assert(NumBits >= MIN_INT_BITS && "bitwidth too small");
    300   assert(NumBits <= MAX_INT_BITS && "bitwidth too large");
    301 
    302   // Check for the built-in integer types
    303   switch (NumBits) {
    304   case   1: return cast<IntegerType>(Type::getInt1Ty(C));
    305   case   8: return cast<IntegerType>(Type::getInt8Ty(C));
    306   case  16: return cast<IntegerType>(Type::getInt16Ty(C));
    307   case  32: return cast<IntegerType>(Type::getInt32Ty(C));
    308   case  64: return cast<IntegerType>(Type::getInt64Ty(C));
    309   case 128: return cast<IntegerType>(Type::getInt128Ty(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] = 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   auto I = pImpl->FunctionTypes.find_as(Key);
    360   FunctionType *FT;
    361 
    362   if (I == pImpl->FunctionTypes.end()) {
    363     FT = (FunctionType*) pImpl->TypeAllocator.
    364       Allocate(sizeof(FunctionType) + sizeof(Type*) * (Params.size() + 1),
    365                AlignOf<FunctionType>::Alignment);
    366     new (FT) FunctionType(ReturnType, Params, isVarArg);
    367     pImpl->FunctionTypes.insert(FT);
    368   } else {
    369     FT = *I;
    370   }
    371 
    372   return FT;
    373 }
    374 
    375 FunctionType *FunctionType::get(Type *Result, bool isVarArg) {
    376   return get(Result, None, isVarArg);
    377 }
    378 
    379 /// isValidReturnType - Return true if the specified type is valid as a return
    380 /// type.
    381 bool FunctionType::isValidReturnType(Type *RetTy) {
    382   return !RetTy->isFunctionTy() && !RetTy->isLabelTy() &&
    383   !RetTy->isMetadataTy();
    384 }
    385 
    386 /// isValidArgumentType - Return true if the specified type is valid as an
    387 /// argument type.
    388 bool FunctionType::isValidArgumentType(Type *ArgTy) {
    389   return ArgTy->isFirstClassType();
    390 }
    391 
    392 //===----------------------------------------------------------------------===//
    393 //                       StructType Implementation
    394 //===----------------------------------------------------------------------===//
    395 
    396 // Primitive Constructors.
    397 
    398 StructType *StructType::get(LLVMContext &Context, ArrayRef<Type*> ETypes,
    399                             bool isPacked) {
    400   LLVMContextImpl *pImpl = Context.pImpl;
    401   AnonStructTypeKeyInfo::KeyTy Key(ETypes, isPacked);
    402   auto I = pImpl->AnonStructTypes.find_as(Key);
    403   StructType *ST;
    404 
    405   if (I == pImpl->AnonStructTypes.end()) {
    406     // Value not found.  Create a new type!
    407     ST = new (Context.pImpl->TypeAllocator) StructType(Context);
    408     ST->setSubclassData(SCDB_IsLiteral);  // Literal struct.
    409     ST->setBody(ETypes, isPacked);
    410     Context.pImpl->AnonStructTypes.insert(ST);
    411   } else {
    412     ST = *I;
    413   }
    414 
    415   return ST;
    416 }
    417 
    418 void StructType::setBody(ArrayRef<Type*> Elements, bool isPacked) {
    419   assert(isOpaque() && "Struct body already set!");
    420 
    421   setSubclassData(getSubclassData() | SCDB_HasBody);
    422   if (isPacked)
    423     setSubclassData(getSubclassData() | SCDB_Packed);
    424 
    425   NumContainedTys = Elements.size();
    426 
    427   if (Elements.empty()) {
    428     ContainedTys = nullptr;
    429     return;
    430   }
    431 
    432   ContainedTys = Elements.copy(getContext().pImpl->TypeAllocator).data();
    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   auto IterBool =
    458       getContext().pImpl->NamedStructTypes.insert(std::make_pair(Name, this));
    459 
    460   // While we have a name collision, try a random rename.
    461   if (!IterBool.second) {
    462     SmallString<64> TempStr(Name);
    463     TempStr.push_back('.');
    464     raw_svector_ostream TmpStream(TempStr);
    465     unsigned NameSize = Name.size();
    466 
    467     do {
    468       TempStr.resize(NameSize + 1);
    469       TmpStream << getContext().pImpl->NamedStructTypesUniqueID++;
    470 
    471       IterBool = getContext().pImpl->NamedStructTypes.insert(
    472           std::make_pair(TmpStream.str(), this));
    473     } while (!IterBool.second);
    474   }
    475 
    476   // Delete the old string data.
    477   if (SymbolTableEntry)
    478     ((EntryTy *)SymbolTableEntry)->Destroy(SymbolTable.getAllocator());
    479   SymbolTableEntry = &*IterBool.first;
    480 }
    481 
    482 //===----------------------------------------------------------------------===//
    483 // StructType Helper functions.
    484 
    485 StructType *StructType::create(LLVMContext &Context, StringRef Name) {
    486   StructType *ST = new (Context.pImpl->TypeAllocator) StructType(Context);
    487   if (!Name.empty())
    488     ST->setName(Name);
    489   return ST;
    490 }
    491 
    492 StructType *StructType::get(LLVMContext &Context, bool isPacked) {
    493   return get(Context, None, isPacked);
    494 }
    495 
    496 StructType *StructType::get(Type *type, ...) {
    497   assert(type && "Cannot create a struct type with no elements with this");
    498   LLVMContext &Ctx = type->getContext();
    499   va_list ap;
    500   SmallVector<llvm::Type*, 8> StructFields;
    501   va_start(ap, type);
    502   while (type) {
    503     StructFields.push_back(type);
    504     type = va_arg(ap, llvm::Type*);
    505   }
    506   auto *Ret = llvm::StructType::get(Ctx, StructFields);
    507   va_end(ap);
    508   return Ret;
    509 }
    510 
    511 StructType *StructType::create(LLVMContext &Context, ArrayRef<Type*> Elements,
    512                                StringRef Name, bool isPacked) {
    513   StructType *ST = create(Context, Name);
    514   ST->setBody(Elements, isPacked);
    515   return ST;
    516 }
    517 
    518 StructType *StructType::create(LLVMContext &Context, ArrayRef<Type*> Elements) {
    519   return create(Context, Elements, StringRef());
    520 }
    521 
    522 StructType *StructType::create(LLVMContext &Context) {
    523   return create(Context, StringRef());
    524 }
    525 
    526 StructType *StructType::create(ArrayRef<Type*> Elements, StringRef Name,
    527                                bool isPacked) {
    528   assert(!Elements.empty() &&
    529          "This method may not be invoked with an empty list");
    530   return create(Elements[0]->getContext(), Elements, Name, isPacked);
    531 }
    532 
    533 StructType *StructType::create(ArrayRef<Type*> Elements) {
    534   assert(!Elements.empty() &&
    535          "This method may not be invoked with an empty list");
    536   return create(Elements[0]->getContext(), Elements, StringRef());
    537 }
    538 
    539 StructType *StructType::create(StringRef Name, Type *type, ...) {
    540   assert(type && "Cannot create a struct type with no elements with this");
    541   LLVMContext &Ctx = type->getContext();
    542   va_list ap;
    543   SmallVector<llvm::Type*, 8> StructFields;
    544   va_start(ap, type);
    545   while (type) {
    546     StructFields.push_back(type);
    547     type = va_arg(ap, llvm::Type*);
    548   }
    549   auto *Ret = llvm::StructType::create(Ctx, StructFields, Name);
    550   va_end(ap);
    551   return Ret;
    552 }
    553 
    554 bool StructType::isSized(SmallPtrSetImpl<Type*> *Visited) const {
    555   if ((getSubclassData() & SCDB_IsSized) != 0)
    556     return true;
    557   if (isOpaque())
    558     return false;
    559 
    560   if (Visited && !Visited->insert(const_cast<StructType*>(this)).second)
    561     return false;
    562 
    563   // Okay, our struct is sized if all of the elements are, but if one of the
    564   // elements is opaque, the struct isn't sized *yet*, but may become sized in
    565   // the future, so just bail out without caching.
    566   for (element_iterator I = element_begin(), E = element_end(); I != E; ++I)
    567     if (!(*I)->isSized(Visited))
    568       return false;
    569 
    570   // Here we cheat a bit and cast away const-ness. The goal is to memoize when
    571   // we find a sized type, as types can only move from opaque to sized, not the
    572   // other way.
    573   const_cast<StructType*>(this)->setSubclassData(
    574     getSubclassData() | SCDB_IsSized);
    575   return true;
    576 }
    577 
    578 StringRef StructType::getName() const {
    579   assert(!isLiteral() && "Literal structs never have names");
    580   if (!SymbolTableEntry) return StringRef();
    581 
    582   return ((StringMapEntry<StructType*> *)SymbolTableEntry)->getKey();
    583 }
    584 
    585 void StructType::setBody(Type *type, ...) {
    586   assert(type && "Cannot create a struct type with no elements with this");
    587   va_list ap;
    588   SmallVector<llvm::Type*, 8> StructFields;
    589   va_start(ap, type);
    590   while (type) {
    591     StructFields.push_back(type);
    592     type = va_arg(ap, llvm::Type*);
    593   }
    594   setBody(StructFields);
    595   va_end(ap);
    596 }
    597 
    598 bool StructType::isValidElementType(Type *ElemTy) {
    599   return !ElemTy->isVoidTy() && !ElemTy->isLabelTy() &&
    600          !ElemTy->isMetadataTy() && !ElemTy->isFunctionTy() &&
    601          !ElemTy->isTokenTy();
    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     return false;
    611 
    612   return elements() == Other->elements();
    613 }
    614 
    615 /// getTypeByName - Return the type with the specified name, or null if there
    616 /// is none by that name.
    617 StructType *Module::getTypeByName(StringRef Name) const {
    618   return getContext().pImpl->NamedStructTypes.lookup(Name);
    619 }
    620 
    621 
    622 //===----------------------------------------------------------------------===//
    623 //                       CompositeType Implementation
    624 //===----------------------------------------------------------------------===//
    625 
    626 Type *CompositeType::getTypeAtIndex(const Value *V) const {
    627   if (auto *STy = dyn_cast<StructType>(this)) {
    628     unsigned Idx =
    629       (unsigned)cast<Constant>(V)->getUniqueInteger().getZExtValue();
    630     assert(indexValid(Idx) && "Invalid structure index!");
    631     return STy->getElementType(Idx);
    632   }
    633 
    634   return cast<SequentialType>(this)->getElementType();
    635 }
    636 
    637 Type *CompositeType::getTypeAtIndex(unsigned Idx) const{
    638   if (auto *STy = dyn_cast<StructType>(this)) {
    639     assert(indexValid(Idx) && "Invalid structure index!");
    640     return STy->getElementType(Idx);
    641   }
    642 
    643   return cast<SequentialType>(this)->getElementType();
    644 }
    645 
    646 bool CompositeType::indexValid(const Value *V) const {
    647   if (auto *STy = dyn_cast<StructType>(this)) {
    648     // Structure indexes require (vectors of) 32-bit integer constants.  In the
    649     // vector case all of the indices must be equal.
    650     if (!V->getType()->getScalarType()->isIntegerTy(32))
    651       return false;
    652     const Constant *C = dyn_cast<Constant>(V);
    653     if (C && V->getType()->isVectorTy())
    654       C = C->getSplatValue();
    655     const ConstantInt *CU = dyn_cast_or_null<ConstantInt>(C);
    656     return CU && CU->getZExtValue() < STy->getNumElements();
    657   }
    658 
    659   // Sequential types can be indexed by any integer.
    660   return V->getType()->isIntOrIntVectorTy();
    661 }
    662 
    663 bool CompositeType::indexValid(unsigned Idx) const {
    664   if (auto *STy = dyn_cast<StructType>(this))
    665     return Idx < STy->getNumElements();
    666   // Sequential types can be indexed by any integer.
    667   return true;
    668 }
    669 
    670 
    671 //===----------------------------------------------------------------------===//
    672 //                           ArrayType Implementation
    673 //===----------------------------------------------------------------------===//
    674 
    675 ArrayType::ArrayType(Type *ElType, uint64_t NumEl)
    676   : SequentialType(ArrayTyID, ElType) {
    677   NumElements = NumEl;
    678 }
    679 
    680 ArrayType *ArrayType::get(Type *ElementType, uint64_t NumElements) {
    681   assert(isValidElementType(ElementType) && "Invalid type for array element!");
    682 
    683   LLVMContextImpl *pImpl = ElementType->getContext().pImpl;
    684   ArrayType *&Entry =
    685     pImpl->ArrayTypes[std::make_pair(ElementType, NumElements)];
    686 
    687   if (!Entry)
    688     Entry = new (pImpl->TypeAllocator) ArrayType(ElementType, NumElements);
    689   return Entry;
    690 }
    691 
    692 bool ArrayType::isValidElementType(Type *ElemTy) {
    693   return !ElemTy->isVoidTy() && !ElemTy->isLabelTy() &&
    694          !ElemTy->isMetadataTy() && !ElemTy->isFunctionTy() &&
    695          !ElemTy->isTokenTy();
    696 }
    697 
    698 //===----------------------------------------------------------------------===//
    699 //                          VectorType Implementation
    700 //===----------------------------------------------------------------------===//
    701 
    702 VectorType::VectorType(Type *ElType, unsigned NumEl)
    703   : SequentialType(VectorTyID, ElType) {
    704   NumElements = NumEl;
    705 }
    706 
    707 VectorType *VectorType::get(Type *ElementType, unsigned NumElements) {
    708   assert(NumElements > 0 && "#Elements of a VectorType must be greater than 0");
    709   assert(isValidElementType(ElementType) && "Element type of a VectorType must "
    710                                             "be an integer, floating point, or "
    711                                             "pointer type.");
    712 
    713   LLVMContextImpl *pImpl = ElementType->getContext().pImpl;
    714   VectorType *&Entry = ElementType->getContext().pImpl
    715     ->VectorTypes[std::make_pair(ElementType, NumElements)];
    716 
    717   if (!Entry)
    718     Entry = new (pImpl->TypeAllocator) VectorType(ElementType, NumElements);
    719   return Entry;
    720 }
    721 
    722 bool VectorType::isValidElementType(Type *ElemTy) {
    723   return ElemTy->isIntegerTy() || ElemTy->isFloatingPointTy() ||
    724     ElemTy->isPointerTy();
    725 }
    726 
    727 //===----------------------------------------------------------------------===//
    728 //                         PointerType Implementation
    729 //===----------------------------------------------------------------------===//
    730 
    731 PointerType *PointerType::get(Type *EltTy, unsigned AddressSpace) {
    732   assert(EltTy && "Can't get a pointer to <null> type!");
    733   assert(isValidElementType(EltTy) && "Invalid type for pointer element!");
    734 
    735   LLVMContextImpl *CImpl = EltTy->getContext().pImpl;
    736 
    737   // Since AddressSpace #0 is the common case, we special case it.
    738   PointerType *&Entry = AddressSpace == 0 ? CImpl->PointerTypes[EltTy]
    739      : CImpl->ASPointerTypes[std::make_pair(EltTy, AddressSpace)];
    740 
    741   if (!Entry)
    742     Entry = new (CImpl->TypeAllocator) PointerType(EltTy, AddressSpace);
    743   return Entry;
    744 }
    745 
    746 
    747 PointerType::PointerType(Type *E, unsigned AddrSpace)
    748   : SequentialType(PointerTyID, E) {
    749 #ifndef NDEBUG
    750   const unsigned oldNCT = NumContainedTys;
    751 #endif
    752   setSubclassData(AddrSpace);
    753   // Check for miscompile. PR11652.
    754   assert(oldNCT == NumContainedTys && "bitfield written out of bounds?");
    755 }
    756 
    757 PointerType *Type::getPointerTo(unsigned addrs) const {
    758   return PointerType::get(const_cast<Type*>(this), addrs);
    759 }
    760 
    761 bool PointerType::isValidElementType(Type *ElemTy) {
    762   return !ElemTy->isVoidTy() && !ElemTy->isLabelTy() &&
    763          !ElemTy->isMetadataTy() && !ElemTy->isTokenTy();
    764 }
    765 
    766 bool PointerType::isLoadableOrStorableType(Type *ElemTy) {
    767   return isValidElementType(ElemTy) && !ElemTy->isFunctionTy();
    768 }
    769