include/llvm/Support/LowLevelTypeImpl.h

   1 //== llvm/Support/LowLevelTypeImpl.h --------------------------- -*- C++ -*-==//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 /// Implement a low-level type suitable for MachineInstr level instruction
  10 /// selection.
  11 ///
  12 /// For a type attached to a MachineInstr, we only care about 2 details: total
  13 /// size and the number of vector lanes (if any). Accordingly, there are 4
  14 /// possible valid type-kinds:
  15 ///
  16 ///    * `sN` for scalars and aggregates
  17 ///    * `<N x sM>` for vectors, which must have at least 2 elements.
  18 ///    * `pN` for pointers
  19 ///
  20 /// Other information required for correct selection is expected to be carried
  21 /// by the opcode, or non-type flags. For example the distinction between G_ADD
  22 /// and G_FADD for int/float or fast-math flags.
  23 //
  24 //===----------------------------------------------------------------------===//
  25
  26 #ifndef LLVM_SUPPORT_LOWLEVELTYPEIMPL_H
  27 #define LLVM_SUPPORT_LOWLEVELTYPEIMPL_H
  28
  29 #include "llvm/ADT/DenseMapInfo.h"
  30 #include "llvm/Support/MachineValueType.h"
  31 #include <cassert>
  32
  33 namespace llvm {
  34
  35 class DataLayout;
  36 class Type;
  37 class raw_ostream;
  38
  39 class LLT {
  40 public:
  41   /// Get a low-level scalar or aggregate "bag of bits".
  42   static LLT scalar(unsigned SizeInBits) {
  43     assert(SizeInBits > 0 && "invalid scalar size");
  44     return LLT{/*isPointer=*/false, /*isVector=*/false, /*NumElements=*/0,
  45                SizeInBits, /*AddressSpace=*/0};
  46   }
  47
  48   /// Get a low-level pointer in the given address space.
  49   static LLT pointer(unsigned AddressSpace, unsigned SizeInBits) {
  50     assert(SizeInBits > 0 && "invalid pointer size");
  51     return LLT{/*isPointer=*/true, /*isVector=*/false, /*NumElements=*/0,
  52                SizeInBits, AddressSpace};
  53   }
  54
  55   /// Get a low-level vector of some number of elements and element width.
  56   /// \p NumElements must be at least 2.
  57   static LLT vector(uint16_t NumElements, unsigned ScalarSizeInBits) {
  58     assert(NumElements > 1 && "invalid number of vector elements");
  59     assert(ScalarSizeInBits > 0 && "invalid vector element size");
  60     return LLT{/*isPointer=*/false, /*isVector=*/true, NumElements,
  61                ScalarSizeInBits, /*AddressSpace=*/0};
  62   }
  63
  64   /// Get a low-level vector of some number of elements and element type.
  65   static LLT vector(uint16_t NumElements, LLT ScalarTy) {
  66     assert(NumElements > 1 && "invalid number of vector elements");
  67     assert(!ScalarTy.isVector() && "invalid vector element type");
  68     return LLT{ScalarTy.isPointer(), /*isVector=*/true, NumElements,
  69                ScalarTy.getSizeInBits(),
  70                ScalarTy.isPointer() ? ScalarTy.getAddressSpace() : 0};
  71   }
  72
  73   static LLT scalarOrVector(uint16_t NumElements, LLT ScalarTy) {
  74     return NumElements == 1 ? ScalarTy : LLT::vector(NumElements, ScalarTy);
  75   }
  76
  77   static LLT scalarOrVector(uint16_t NumElements, unsigned ScalarSize) {
  78     return scalarOrVector(NumElements, LLT::scalar(ScalarSize));
  79   }
  80
  81   explicit LLT(bool isPointer, bool isVector, uint16_t NumElements,
  82                unsigned SizeInBits, unsigned AddressSpace) {
  83     init(isPointer, isVector, NumElements, SizeInBits, AddressSpace);
  84   }
  85   explicit LLT() : IsPointer(false), IsVector(false), RawData(0) {}
  86
  87   explicit LLT(MVT VT);
  88
  89   bool isValid() const { return RawData != 0; }
  90
  91   bool isScalar() const { return isValid() && !IsPointer && !IsVector; }
  92
  93   bool isPointer() const { return isValid() && IsPointer && !IsVector; }
  94
  95   bool isVector() const { return isValid() && IsVector; }
  96
  97   /// Returns the number of elements in a vector LLT. Must only be called on
  98   /// vector types.
  99   uint16_t getNumElements() const {
 100     assert(IsVector && "cannot get number of elements on scalar/aggregate");
 101     if (!IsPointer)
 102       return getFieldValue(VectorElementsFieldInfo);
 103     else
 104       return getFieldValue(PointerVectorElementsFieldInfo);
 105   }
 106
 107   /// Returns the total size of the type. Must only be called on sized types.
 108   unsigned getSizeInBits() const {
 109     if (isPointer() || isScalar())
 110       return getScalarSizeInBits();
 111     return getScalarSizeInBits() * getNumElements();
 112   }
 113
 114   LLT getScalarType() const {
 115     return isVector() ? getElementType() : *this;
 116   }
 117
 118   /// If this type is a vector, return a vector with the same number of elements
 119   /// but the new element type. Otherwise, return the new element type.
 120   LLT changeElementType(LLT NewEltTy) const {
 121     return isVector() ? LLT::vector(getNumElements(), NewEltTy) : NewEltTy;
 122   }
 123
 124   /// If this type is a vector, return a vector with the same number of elements
 125   /// but the new element size. Otherwise, return the new element type. Invalid
 126   /// for pointer types. For pointer types, use changeElementType.
 127   LLT changeElementSize(unsigned NewEltSize) const {
 128     assert(!getScalarType().isPointer() &&
 129            "invalid to directly change element size for pointers");
 130     return isVector() ? LLT::vector(getNumElements(), NewEltSize)
 131                       : LLT::scalar(NewEltSize);
 132   }
 133
 134   unsigned getScalarSizeInBits() const {
 135     assert(RawData != 0 && "Invalid Type");
 136     if (!IsVector) {
 137       if (!IsPointer)
 138         return getFieldValue(ScalarSizeFieldInfo);
 139       else
 140         return getFieldValue(PointerSizeFieldInfo);
 141     } else {
 142       if (!IsPointer)
 143         return getFieldValue(VectorSizeFieldInfo);
 144       else
 145         return getFieldValue(PointerVectorSizeFieldInfo);
 146     }
 147   }
 148
 149   unsigned getAddressSpace() const {
 150     assert(RawData != 0 && "Invalid Type");
 151     assert(IsPointer && "cannot get address space of non-pointer type");
 152     if (!IsVector)
 153       return getFieldValue(PointerAddressSpaceFieldInfo);
 154     else
 155       return getFieldValue(PointerVectorAddressSpaceFieldInfo);
 156   }
 157
 158   /// Returns the vector's element type. Only valid for vector types.
 159   LLT getElementType() const {
 160     assert(isVector() && "cannot get element type of scalar/aggregate");
 161     if (IsPointer)
 162       return pointer(getAddressSpace(), getScalarSizeInBits());
 163     else
 164       return scalar(getScalarSizeInBits());
 165   }
 166
 167   void print(raw_ostream &OS) const;
 168
 169   bool operator==(const LLT &RHS) const {
 170     return IsPointer == RHS.IsPointer && IsVector == RHS.IsVector &&
 171            RHS.RawData == RawData;
 172   }
 173
 174   bool operator!=(const LLT &RHS) const { return !(*this == RHS); }
 175
 176   friend struct DenseMapInfo<LLT>;
 177   friend class GISelInstProfileBuilder;
 178
 179 private:
 180   /// LLT is packed into 64 bits as follows:
 181   /// isPointer : 1
 182   /// isVector  : 1
 183   /// with 62 bits remaining for Kind-specific data, packed in bitfields
 184   /// as described below. As there isn't a simple portable way to pack bits
 185   /// into bitfields, here the different fields in the packed structure is
 186   /// described in static const *Field variables. Each of these variables
 187   /// is a 2-element array, with the first element describing the bitfield size
 188   /// and the second element describing the bitfield offset.
 189   typedef int BitFieldInfo[2];
 190   ///
 191   /// This is how the bitfields are packed per Kind:
 192   /// * Invalid:
 193   ///   gets encoded as RawData == 0, as that is an invalid encoding, since for
 194   ///   valid encodings, SizeInBits/SizeOfElement must be larger than 0.
 195   /// * Non-pointer scalar (isPointer == 0 && isVector == 0):
 196   ///   SizeInBits: 32;
 197   static const constexpr BitFieldInfo ScalarSizeFieldInfo{32, 0};
 198   /// * Pointer (isPointer == 1 && isVector == 0):
 199   ///   SizeInBits: 16;
 200   ///   AddressSpace: 24;
 201   static const constexpr BitFieldInfo PointerSizeFieldInfo{16, 0};
 202   static const constexpr BitFieldInfo PointerAddressSpaceFieldInfo{
 203       24, PointerSizeFieldInfo[0] + PointerSizeFieldInfo[1]};
 204   /// * Vector-of-non-pointer (isPointer == 0 && isVector == 1):
 205   ///   NumElements: 16;
 206   ///   SizeOfElement: 32;
 207   static const constexpr BitFieldInfo VectorElementsFieldInfo{16, 0};
 208   static const constexpr BitFieldInfo VectorSizeFieldInfo{
 209       32, VectorElementsFieldInfo[0] + VectorElementsFieldInfo[1]};
 210   /// * Vector-of-pointer (isPointer == 1 && isVector == 1):
 211   ///   NumElements: 16;
 212   ///   SizeOfElement: 16;
 213   ///   AddressSpace: 24;
 214   static const constexpr BitFieldInfo PointerVectorElementsFieldInfo{16, 0};
 215   static const constexpr BitFieldInfo PointerVectorSizeFieldInfo{
 216       16,
 217       PointerVectorElementsFieldInfo[1] + PointerVectorElementsFieldInfo[0]};
 218   static const constexpr BitFieldInfo PointerVectorAddressSpaceFieldInfo{
 219       24, PointerVectorSizeFieldInfo[1] + PointerVectorSizeFieldInfo[0]};
 220
 221   uint64_t IsPointer : 1;
 222   uint64_t IsVector : 1;
 223   uint64_t RawData : 62;
 224
 225   static uint64_t getMask(const BitFieldInfo FieldInfo) {
 226     const int FieldSizeInBits = FieldInfo[0];
 227     return (((uint64_t)1) << FieldSizeInBits) - 1;
 228   }
 229   static uint64_t maskAndShift(uint64_t Val, uint64_t Mask, uint8_t Shift) {
 230     assert(Val <= Mask && "Value too large for field");
 231     return (Val & Mask) << Shift;
 232   }
 233   static uint64_t maskAndShift(uint64_t Val, const BitFieldInfo FieldInfo) {
 234     return maskAndShift(Val, getMask(FieldInfo), FieldInfo[1]);
 235   }
 236   uint64_t getFieldValue(const BitFieldInfo FieldInfo) const {
 237     return getMask(FieldInfo) & (RawData >> FieldInfo[1]);
 238   }
 239
 240   void init(bool IsPointer, bool IsVector, uint16_t NumElements,
 241             unsigned SizeInBits, unsigned AddressSpace) {
 242     this->IsPointer = IsPointer;
 243     this->IsVector = IsVector;
 244     if (!IsVector) {
 245       if (!IsPointer)
 246         RawData = maskAndShift(SizeInBits, ScalarSizeFieldInfo);
 247       else
 248         RawData = maskAndShift(SizeInBits, PointerSizeFieldInfo) |
 249                   maskAndShift(AddressSpace, PointerAddressSpaceFieldInfo);
 250     } else {
 251       assert(NumElements > 1 && "invalid number of vector elements");
 252       if (!IsPointer)
 253         RawData = maskAndShift(NumElements, VectorElementsFieldInfo) |
 254                   maskAndShift(SizeInBits, VectorSizeFieldInfo);
 255       else
 256         RawData =
 257             maskAndShift(NumElements, PointerVectorElementsFieldInfo) |
 258             maskAndShift(SizeInBits, PointerVectorSizeFieldInfo) |
 259             maskAndShift(AddressSpace, PointerVectorAddressSpaceFieldInfo);
 260     }
 261   }
 262
 263   uint64_t getUniqueRAWLLTData() const {
 264     return ((uint64_t)RawData) << 2 | ((uint64_t)IsPointer) << 1 |
 265            ((uint64_t)IsVector);
 266   }
 267 };
 268
 269 inline raw_ostream& operator<<(raw_ostream &OS, const LLT &Ty) {
 270   Ty.print(OS);
 271   return OS;
 272 }
 273
 274 template<> struct DenseMapInfo<LLT> {
 275   static inline LLT getEmptyKey() {
 276     LLT Invalid;
 277     Invalid.IsPointer = true;
 278     return Invalid;
 279   }
 280   static inline LLT getTombstoneKey() {
 281     LLT Invalid;
 282     Invalid.IsVector = true;
 283     return Invalid;
 284   }
 285   static inline unsigned getHashValue(const LLT &Ty) {
 286     uint64_t Val = Ty.getUniqueRAWLLTData();
 287     return DenseMapInfo<uint64_t>::getHashValue(Val);
 288   }
 289   static bool isEqual(const LLT &LHS, const LLT &RHS) {
 290     return LHS == RHS;
 291   }
 292 };
 293
 294 }
 295
 296 #endif // LLVM_SUPPORT_LOWLEVELTYPEIMPL_H