third_party/skia/src/sksl/SkSLContext.h

/*
 * Copyright 2016 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef SKSL_CONTEXT
#define SKSL_CONTEXT

#include "src/sksl/ir/SkSLExpression.h"
#include "src/sksl/ir/SkSLType.h"

namespace SkSL {

/**
 * Contains compiler-wide objects, which currently means the core types.
 */
class Context {
public:
    Context()
    : fInvalid_Type(new Type("<INVALID>"))
    , fVoid_Type(new Type("void"))
    , fNull_Type(new Type("null"))
    , fFloatLiteral_Type(new Type("$floatLiteral", Type::kFloat_NumberKind, 3))
    , fIntLiteral_Type(new Type("$intLiteral", Type::kSigned_NumberKind, 1))
    , fDouble_Type(new Type("double", Type::kFloat_NumberKind, 6, true))
    , fDouble2_Type(new Type("double2", *fDouble_Type, 2))
    , fDouble3_Type(new Type("double3", *fDouble_Type, 3))
    , fDouble4_Type(new Type("double4", *fDouble_Type, 4))
    , fFloat_Type(new Type("float", Type::kFloat_NumberKind, 5, true))
    , fFloat2_Type(new Type("float2", *fFloat_Type, 2))
    , fFloat3_Type(new Type("float3", *fFloat_Type, 3))
    , fFloat4_Type(new Type("float4", *fFloat_Type, 4))
    , fHalf_Type(new Type("half", Type::kFloat_NumberKind, 4))
    , fHalf2_Type(new Type("half2", *fHalf_Type, 2))
    , fHalf3_Type(new Type("half3", *fHalf_Type, 3))
    , fHalf4_Type(new Type("half4", *fHalf_Type, 4))
    , fUInt_Type(new Type("uint", Type::kUnsigned_NumberKind, 2, true))
    , fUInt2_Type(new Type("uint2", *fUInt_Type, 2))
    , fUInt3_Type(new Type("uint3", *fUInt_Type, 3))
    , fUInt4_Type(new Type("uint4", *fUInt_Type, 4))
    , fInt_Type(new Type("int", Type::kSigned_NumberKind, 2, true))
    , fInt2_Type(new Type("int2", *fInt_Type, 2))
    , fInt3_Type(new Type("int3", *fInt_Type, 3))
    , fInt4_Type(new Type("int4", *fInt_Type, 4))
    , fUShort_Type(new Type("ushort", Type::kUnsigned_NumberKind, 0))
    , fUShort2_Type(new Type("ushort2", *fUShort_Type, 2))
    , fUShort3_Type(new Type("ushort3", *fUShort_Type, 3))
    , fUShort4_Type(new Type("ushort4", *fUShort_Type, 4))
    , fShort_Type(new Type("short", Type::kSigned_NumberKind, 0))
    , fShort2_Type(new Type("short2", *fShort_Type, 2))
    , fShort3_Type(new Type("short3", *fShort_Type, 3))
    , fShort4_Type(new Type("short4", *fShort_Type, 4))
    , fUByte_Type(new Type("ubyte", Type::kUnsigned_NumberKind, 0))
    , fUByte2_Type(new Type("ubyte2", *fUByte_Type, 2))
    , fUByte3_Type(new Type("ubyte3", *fUByte_Type, 3))
    , fUByte4_Type(new Type("ubyte4", *fUByte_Type, 4))
    , fByte_Type(new Type("byte", Type::kSigned_NumberKind, 0))
    , fByte2_Type(new Type("byte2", *fByte_Type, 2))
    , fByte3_Type(new Type("byte3", *fByte_Type, 3))
    , fByte4_Type(new Type("byte4", *fByte_Type, 4))
    , fBool_Type(new Type("bool", Type::kNonnumeric_NumberKind, -1))
    , fBool2_Type(new Type("bool2", *fBool_Type, 2))
    , fBool3_Type(new Type("bool3", *fBool_Type, 3))
    , fBool4_Type(new Type("bool4", *fBool_Type, 4))
    , fFloat2x2_Type(new Type("float2x2", *fFloat_Type, 2, 2))
    , fFloat2x3_Type(new Type("float2x3", *fFloat_Type, 2, 3))
    , fFloat2x4_Type(new Type("float2x4", *fFloat_Type, 2, 4))
    , fFloat3x2_Type(new Type("float3x2", *fFloat_Type, 3, 2))
    , fFloat3x3_Type(new Type("float3x3", *fFloat_Type, 3, 3))
    , fFloat3x4_Type(new Type("float3x4", *fFloat_Type, 3, 4))
    , fFloat4x2_Type(new Type("float4x2", *fFloat_Type, 4, 2))
    , fFloat4x3_Type(new Type("float4x3", *fFloat_Type, 4, 3))
    , fFloat4x4_Type(new Type("float4x4", *fFloat_Type, 4, 4))
    , fHalf2x2_Type(new Type("half2x2", *fHalf_Type, 2, 2))
    , fHalf2x3_Type(new Type("half2x3", *fHalf_Type, 2, 3))
    , fHalf2x4_Type(new Type("half2x4", *fHalf_Type, 2, 4))
    , fHalf3x2_Type(new Type("half3x2", *fHalf_Type, 3, 2))
    , fHalf3x3_Type(new Type("half3x3", *fHalf_Type, 3, 3))
    , fHalf3x4_Type(new Type("half3x4", *fHalf_Type, 3, 4))
    , fHalf4x2_Type(new Type("half4x2", *fHalf_Type, 4, 2))
    , fHalf4x3_Type(new Type("half4x3", *fHalf_Type, 4, 3))
    , fHalf4x4_Type(new Type("half4x4", *fHalf_Type, 4, 4))
    , fDouble2x2_Type(new Type("double2x2", *fDouble_Type, 2, 2))
    , fDouble2x3_Type(new Type("double2x3", *fDouble_Type, 2, 3))
    , fDouble2x4_Type(new Type("double2x4", *fDouble_Type, 2, 4))
    , fDouble3x2_Type(new Type("double3x2", *fDouble_Type, 3, 2))
    , fDouble3x3_Type(new Type("double3x3", *fDouble_Type, 3, 3))
    , fDouble3x4_Type(new Type("double3x4", *fDouble_Type, 3, 4))
    , fDouble4x2_Type(new Type("double4x2", *fDouble_Type, 4, 2))
    , fDouble4x3_Type(new Type("double4x3", *fDouble_Type, 4, 3))
    , fDouble4x4_Type(new Type("double4x4", *fDouble_Type, 4, 4))
    , fTexture1D_Type(new Type("texture1D", SpvDim1D, false, false, false, true))
    , fTexture2D_Type(new Type("texture2D", SpvDim2D, false, false, false, true))
    , fTexture3D_Type(new Type("texture3D", SpvDim3D, false, false, false, true))
    , fTextureExternalOES_Type(new Type("textureExternalOES", SpvDim2D, false, false, false, true))
    , fTextureCube_Type(new Type("textureCube", SpvDimCube, false, false, false, true))
    , fTexture2DRect_Type(new Type("texture2DRect", SpvDimRect, false, false, false, true))
    , fTextureBuffer_Type(new Type("textureBuffer", SpvDimBuffer, false, false, false, true))
    , fITexture2D_Type(new Type("itexture2D", SpvDim2D, false, false, false, true))
    , fSampler1D_Type(new Type("sampler1D", *fTexture1D_Type))
    , fSampler2D_Type(new Type("sampler2D", *fTexture2D_Type))
    , fSampler3D_Type(new Type("sampler3D", *fTexture3D_Type))
    , fSamplerExternalOES_Type(new Type("samplerExternalOES", *fTextureExternalOES_Type))
    , fSamplerCube_Type(new Type("samplerCube", *fTextureCube_Type))
    , fSampler2DRect_Type(new Type("sampler2DRect", *fTexture2DRect_Type))
    , fSampler1DArray_Type(new Type("sampler1DArray"))
    , fSampler2DArray_Type(new Type("sampler2DArray"))
    , fSamplerCubeArray_Type(new Type("samplerCubeArray"))
    , fSamplerBuffer_Type(new Type("samplerBuffer", *fTextureBuffer_Type))
    , fSampler2DMS_Type(new Type("sampler2DMS"))
    , fSampler2DMSArray_Type(new Type("sampler2DMSArray"))
    , fSampler1DShadow_Type(new Type("sampler1DShadow"))
    , fSampler2DShadow_Type(new Type("sampler2DShadow"))
    , fSamplerCubeShadow_Type(new Type("samplerCubeShadow"))
    , fSampler2DRectShadow_Type(new Type("sampler2DRectShadow"))
    , fSampler1DArrayShadow_Type(new Type("sampler1DArrayShadow"))
    , fSampler2DArrayShadow_Type(new Type("sampler2DArrayShadow"))
    , fSamplerCubeArrayShadow_Type(new Type("samplerCubeArrayShadow"))

    // Related to below FIXME, gsampler*s don't currently expand to cover integer case.
    , fISampler2D_Type(new Type("isampler2D", *fITexture2D_Type))

    , fSampler_Type(new Type("sampler", Type::kSeparateSampler_Kind))
    // FIXME express these as "gimage2D" that expand to image2D, iimage2D, and uimage2D.
    , fImage2D_Type(new Type("image2D", SpvDim2D, false, false, false, true))
    , fIImage2D_Type(new Type("iimage2D", SpvDim2D, false, false, false, true))

    // FIXME express these as "gsubpassInput" that expand to subpassInput, isubpassInput,
    // and usubpassInput.
    , fSubpassInput_Type(new Type("subpassInput", SpvDimSubpassData, false, false,
                                  false, false))
    , fSubpassInputMS_Type(new Type("subpassInputMS", SpvDimSubpassData, false, false,
                                    true, false))

    // FIXME figure out what we're supposed to do with the gsampler et al. types)
    , fGSampler1D_Type(new Type("$gsampler1D", static_type(*fSampler1D_Type)))
    , fGSampler2D_Type(new Type("$gsampler2D", static_type(*fSampler2D_Type)))
    , fGSampler3D_Type(new Type("$gsampler3D", static_type(*fSampler3D_Type)))
    , fGSamplerCube_Type(new Type("$gsamplerCube", static_type(*fSamplerCube_Type)))
    , fGSampler2DRect_Type(new Type("$gsampler2DRect", static_type(*fSampler2DRect_Type)))
    , fGSampler1DArray_Type(new Type("$gsampler1DArray",
                                     static_type(*fSampler1DArray_Type)))
    , fGSampler2DArray_Type(new Type("$gsampler2DArray",
                                     static_type(*fSampler2DArray_Type)))
    , fGSamplerCubeArray_Type(new Type("$gsamplerCubeArray",
                                       static_type(*fSamplerCubeArray_Type)))
    , fGSamplerBuffer_Type(new Type("$gsamplerBuffer", static_type(*fSamplerBuffer_Type)))
    , fGSampler2DMS_Type(new Type("$gsampler2DMS", static_type(*fSampler2DMS_Type)))
    , fGSampler2DMSArray_Type(new Type("$gsampler2DMSArray",
                                       static_type(*fSampler2DMSArray_Type)))
    , fGSampler2DArrayShadow_Type(new Type("$gsampler2DArrayShadow",
                                           static_type(*fSampler2DArrayShadow_Type)))
    , fGSamplerCubeArrayShadow_Type(new Type("$gsamplerCubeArrayShadow",
                                             static_type(*fSamplerCubeArrayShadow_Type)))
    , fGenType_Type(new Type("$genType", { fFloat_Type.get(), fFloat2_Type.get(),
                                           fFloat3_Type.get(), fFloat4_Type.get() }))
    , fGenHType_Type(new Type("$genHType", { fHalf_Type.get(), fHalf2_Type.get(),
                                             fHalf3_Type.get(), fHalf4_Type.get() }))
    , fGenDType_Type(new Type("$genDType", { fDouble_Type.get(), fDouble2_Type.get(),
                                             fDouble3_Type.get(), fDouble4_Type.get() }))
    , fGenIType_Type(new Type("$genIType", { fInt_Type.get(), fInt2_Type.get(),
                                             fInt3_Type.get(), fInt4_Type.get() }))
    , fGenUType_Type(new Type("$genUType", { fUInt_Type.get(), fUInt2_Type.get(),
                                             fUInt3_Type.get(), fUInt4_Type.get() }))
    , fGenBType_Type(new Type("$genBType", { fBool_Type.get(), fBool2_Type.get(),
                                             fBool3_Type.get(), fBool4_Type.get() }))
    , fMat_Type(new Type("$mat", { fFloat2x2_Type.get(),  fFloat2x3_Type.get(),
                                   fFloat2x4_Type.get(),  fFloat3x2_Type.get(),
                                   fFloat3x3_Type.get(),  fFloat3x4_Type.get(),
                                   fFloat4x2_Type.get(),  fFloat4x3_Type.get(),
                                   fFloat4x4_Type.get(),  fHalf2x2_Type.get(),
                                   fHalf2x3_Type.get(),   fHalf2x4_Type.get(),
                                   fHalf3x2_Type.get(),   fHalf3x3_Type.get(),
                                   fHalf3x4_Type.get(),   fHalf4x2_Type.get(),
                                   fHalf4x3_Type.get(),   fHalf4x4_Type.get(),
                                   fDouble2x2_Type.get(), fDouble2x3_Type.get(),
                                   fDouble2x4_Type.get(), fDouble3x2_Type.get(),
                                   fDouble3x3_Type.get(), fDouble3x4_Type.get(),
                                   fDouble4x2_Type.get(), fDouble4x3_Type.get(),
                                   fDouble4x4_Type.get() }))
    , fVec_Type(new Type("$vec", { fInvalid_Type.get(), fFloat2_Type.get(),
                                           fFloat3_Type.get(), fFloat4_Type.get() }))
    , fGVec_Type(new Type("$gvec"))
    , fGVec2_Type(new Type("$gfloat2"))
    , fGVec3_Type(new Type("$gfloat3"))
    , fGVec4_Type(new Type("$gfloat4", static_type(*fFloat4_Type)))
    , fHVec_Type(new Type("$hvec", { fInvalid_Type.get(), fHalf2_Type.get(),
                                     fHalf3_Type.get(), fHalf4_Type.get() }))
    , fDVec_Type(new Type("$dvec", { fInvalid_Type.get(), fDouble2_Type.get(),
                                     fDouble3_Type.get(), fDouble4_Type.get() }))
    , fIVec_Type(new Type("$ivec", { fInvalid_Type.get(), fInt2_Type.get(),
                                     fInt3_Type.get(), fInt4_Type.get() }))
    , fUVec_Type(new Type("$uvec", { fInvalid_Type.get(), fUInt2_Type.get(),
                                     fUInt3_Type.get(), fUInt4_Type.get() }))
    , fSVec_Type(new Type("$svec", { fInvalid_Type.get(), fShort2_Type.get(),
                                     fShort3_Type.get(), fShort4_Type.get() }))
    , fUSVec_Type(new Type("$usvec", { fInvalid_Type.get(), fUShort2_Type.get(),
                                       fUShort3_Type.get(), fUShort4_Type.get() }))
    , fByteVec_Type(new Type("$bytevec", { fInvalid_Type.get(), fByte2_Type.get(),
                                     fByte3_Type.get(), fByte4_Type.get() }))
    , fUByteVec_Type(new Type("$ubytevec", { fInvalid_Type.get(), fUByte2_Type.get(),
                                       fUByte3_Type.get(), fUByte4_Type.get() }))
    , fBVec_Type(new Type("$bvec", { fInvalid_Type.get(), fBool2_Type.get(),
                                     fBool3_Type.get(), fBool4_Type.get() }))
    , fSkCaps_Type(new Type("$sk_Caps"))
    , fSkArgs_Type(new Type("$sk_Args"))
    , fFragmentProcessor_Type(fp_type(fInt_Type.get(), fBool_Type.get()))
    , fDefined_Expression(new Defined(*fInvalid_Type)) {}

    static std::vector<const Type*> static_type(const Type& t) {
        return { &t, &t, &t, &t };
    }

    const std::unique_ptr<Type> fInvalid_Type;
    const std::unique_ptr<Type> fVoid_Type;
    const std::unique_ptr<Type> fNull_Type;
    const std::unique_ptr<Type> fFloatLiteral_Type;
    const std::unique_ptr<Type> fIntLiteral_Type;

    const std::unique_ptr<Type> fDouble_Type;
    const std::unique_ptr<Type> fDouble2_Type;
    const std::unique_ptr<Type> fDouble3_Type;
    const std::unique_ptr<Type> fDouble4_Type;

    const std::unique_ptr<Type> fFloat_Type;
    const std::unique_ptr<Type> fFloat2_Type;
    const std::unique_ptr<Type> fFloat3_Type;
    const std::unique_ptr<Type> fFloat4_Type;

    const std::unique_ptr<Type> fHalf_Type;
    const std::unique_ptr<Type> fHalf2_Type;
    const std::unique_ptr<Type> fHalf3_Type;
    const std::unique_ptr<Type> fHalf4_Type;

    const std::unique_ptr<Type> fUInt_Type;
    const std::unique_ptr<Type> fUInt2_Type;
    const std::unique_ptr<Type> fUInt3_Type;
    const std::unique_ptr<Type> fUInt4_Type;

    const std::unique_ptr<Type> fInt_Type;
    const std::unique_ptr<Type> fInt2_Type;
    const std::unique_ptr<Type> fInt3_Type;
    const std::unique_ptr<Type> fInt4_Type;

    const std::unique_ptr<Type> fUShort_Type;
    const std::unique_ptr<Type> fUShort2_Type;
    const std::unique_ptr<Type> fUShort3_Type;
    const std::unique_ptr<Type> fUShort4_Type;

    const std::unique_ptr<Type> fShort_Type;
    const std::unique_ptr<Type> fShort2_Type;
    const std::unique_ptr<Type> fShort3_Type;
    const std::unique_ptr<Type> fShort4_Type;

    const std::unique_ptr<Type> fUByte_Type;
    const std::unique_ptr<Type> fUByte2_Type;
    const std::unique_ptr<Type> fUByte3_Type;
    const std::unique_ptr<Type> fUByte4_Type;

    const std::unique_ptr<Type> fByte_Type;
    const std::unique_ptr<Type> fByte2_Type;
    const std::unique_ptr<Type> fByte3_Type;
    const std::unique_ptr<Type> fByte4_Type;

    const std::unique_ptr<Type> fBool_Type;
    const std::unique_ptr<Type> fBool2_Type;
    const std::unique_ptr<Type> fBool3_Type;
    const std::unique_ptr<Type> fBool4_Type;

    const std::unique_ptr<Type> fFloat2x2_Type;
    const std::unique_ptr<Type> fFloat2x3_Type;
    const std::unique_ptr<Type> fFloat2x4_Type;
    const std::unique_ptr<Type> fFloat3x2_Type;
    const std::unique_ptr<Type> fFloat3x3_Type;
    const std::unique_ptr<Type> fFloat3x4_Type;
    const std::unique_ptr<Type> fFloat4x2_Type;
    const std::unique_ptr<Type> fFloat4x3_Type;
    const std::unique_ptr<Type> fFloat4x4_Type;

    const std::unique_ptr<Type> fHalf2x2_Type;
    const std::unique_ptr<Type> fHalf2x3_Type;
    const std::unique_ptr<Type> fHalf2x4_Type;
    const std::unique_ptr<Type> fHalf3x2_Type;
    const std::unique_ptr<Type> fHalf3x3_Type;
    const std::unique_ptr<Type> fHalf3x4_Type;
    const std::unique_ptr<Type> fHalf4x2_Type;
    const std::unique_ptr<Type> fHalf4x3_Type;
    const std::unique_ptr<Type> fHalf4x4_Type;

    const std::unique_ptr<Type> fDouble2x2_Type;
    const std::unique_ptr<Type> fDouble2x3_Type;
    const std::unique_ptr<Type> fDouble2x4_Type;
    const std::unique_ptr<Type> fDouble3x2_Type;
    const std::unique_ptr<Type> fDouble3x3_Type;
    const std::unique_ptr<Type> fDouble3x4_Type;
    const std::unique_ptr<Type> fDouble4x2_Type;
    const std::unique_ptr<Type> fDouble4x3_Type;
    const std::unique_ptr<Type> fDouble4x4_Type;

    const std::unique_ptr<Type> fTexture1D_Type;
    const std::unique_ptr<Type> fTexture2D_Type;
    const std::unique_ptr<Type> fTexture3D_Type;
    const std::unique_ptr<Type> fTextureExternalOES_Type;
    const std::unique_ptr<Type> fTextureCube_Type;
    const std::unique_ptr<Type> fTexture2DRect_Type;
    const std::unique_ptr<Type> fTextureBuffer_Type;
    const std::unique_ptr<Type> fITexture2D_Type;

    const std::unique_ptr<Type> fSampler1D_Type;
    const std::unique_ptr<Type> fSampler2D_Type;
    const std::unique_ptr<Type> fSampler3D_Type;
    const std::unique_ptr<Type> fSamplerExternalOES_Type;
    const std::unique_ptr<Type> fSamplerCube_Type;
    const std::unique_ptr<Type> fSampler2DRect_Type;
    const std::unique_ptr<Type> fSampler1DArray_Type;
    const std::unique_ptr<Type> fSampler2DArray_Type;
    const std::unique_ptr<Type> fSamplerCubeArray_Type;
    const std::unique_ptr<Type> fSamplerBuffer_Type;
    const std::unique_ptr<Type> fSampler2DMS_Type;
    const std::unique_ptr<Type> fSampler2DMSArray_Type;
    const std::unique_ptr<Type> fSampler1DShadow_Type;
    const std::unique_ptr<Type> fSampler2DShadow_Type;
    const std::unique_ptr<Type> fSamplerCubeShadow_Type;
    const std::unique_ptr<Type> fSampler2DRectShadow_Type;
    const std::unique_ptr<Type> fSampler1DArrayShadow_Type;
    const std::unique_ptr<Type> fSampler2DArrayShadow_Type;
    const std::unique_ptr<Type> fSamplerCubeArrayShadow_Type;

    const std::unique_ptr<Type> fISampler2D_Type;
    const std::unique_ptr<Type> fSampler_Type;

    const std::unique_ptr<Type> fImage2D_Type;
    const std::unique_ptr<Type> fIImage2D_Type;

    const std::unique_ptr<Type> fSubpassInput_Type;
    const std::unique_ptr<Type> fSubpassInputMS_Type;

    const std::unique_ptr<Type> fGSampler1D_Type;
    const std::unique_ptr<Type> fGSampler2D_Type;
    const std::unique_ptr<Type> fGSampler3D_Type;
    const std::unique_ptr<Type> fGSamplerCube_Type;
    const std::unique_ptr<Type> fGSampler2DRect_Type;
    const std::unique_ptr<Type> fGSampler1DArray_Type;
    const std::unique_ptr<Type> fGSampler2DArray_Type;
    const std::unique_ptr<Type> fGSamplerCubeArray_Type;
    const std::unique_ptr<Type> fGSamplerBuffer_Type;
    const std::unique_ptr<Type> fGSampler2DMS_Type;
    const std::unique_ptr<Type> fGSampler2DMSArray_Type;
    const std::unique_ptr<Type> fGSampler2DArrayShadow_Type;
    const std::unique_ptr<Type> fGSamplerCubeArrayShadow_Type;

    const std::unique_ptr<Type> fGenType_Type;
    const std::unique_ptr<Type> fGenHType_Type;
    const std::unique_ptr<Type> fGenDType_Type;
    const std::unique_ptr<Type> fGenIType_Type;
    const std::unique_ptr<Type> fGenUType_Type;
    const std::unique_ptr<Type> fGenBType_Type;

    const std::unique_ptr<Type> fMat_Type;

    const std::unique_ptr<Type> fVec_Type;

    const std::unique_ptr<Type> fGVec_Type;
    const std::unique_ptr<Type> fGVec2_Type;
    const std::unique_ptr<Type> fGVec3_Type;
    const std::unique_ptr<Type> fGVec4_Type;
    const std::unique_ptr<Type> fHVec_Type;
    const std::unique_ptr<Type> fDVec_Type;
    const std::unique_ptr<Type> fIVec_Type;
    const std::unique_ptr<Type> fUVec_Type;
    const std::unique_ptr<Type> fSVec_Type;
    const std::unique_ptr<Type> fUSVec_Type;
    const std::unique_ptr<Type> fByteVec_Type;
    const std::unique_ptr<Type> fUByteVec_Type;

    const std::unique_ptr<Type> fBVec_Type;

    const std::unique_ptr<Type> fSkCaps_Type;
    const std::unique_ptr<Type> fSkArgs_Type;
    const std::unique_ptr<Type> fFragmentProcessor_Type;

    // dummy expression used to mark that a variable has a value during dataflow analysis (when it
    // could have several different values, or the analyzer is otherwise unable to assign it a
    // specific expression)
    const std::unique_ptr<Expression> fDefined_Expression;

private:
    class Defined : public Expression {
    public:
        Defined(const Type& type)
        : INHERITED(-1, kDefined_Kind, type) {}

        bool hasSideEffects() const override {
            return false;
        }

        String description() const override {
            return "<defined>";
        }

        std::unique_ptr<Expression> clone() const override {
            return std::unique_ptr<Expression>(new Defined(fType));
        }

        typedef Expression INHERITED;
    };

    static std::unique_ptr<Type> fp_type(const Type* intType, const Type* boolType) {
        // Build fields for FragmentProcessors, which should parallel the
        // C++ API for GrFragmentProcessor.
        Modifiers mods(Layout(), Modifiers::kConst_Flag);
        std::vector<Type::Field> fields = {
            Type::Field(mods, "numTextureSamplers", intType),
            Type::Field(mods, "numCoordTransforms", intType),
            Type::Field(mods, "numChildProcessors", intType),
            Type::Field(mods, "usesLocalCoords", boolType),
            Type::Field(mods, "compatibleWithCoverageAsAlpha", boolType),
            Type::Field(mods, "preservesOpaqueInput", boolType),
            Type::Field(mods, "hasConstantOutputForConstantInput", boolType)
        };
        return std::unique_ptr<Type>(new Type("fragmentProcessor", fields));
    }
};

} // namespace

#endif