Merge pull request #2431 from scribam/cmake-minimum-required

[KhronosGroup/SPIRV-Cross.git] / spirv_common.hpp

/*
 * Copyright 2015-2021 Arm Limited
 * SPDX-License-Identifier: Apache-2.0 OR MIT
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/*
 * At your option, you may choose to accept this material under either:
 *  1. The Apache License, Version 2.0, found at <http://www.apache.org/licenses/LICENSE-2.0>, or
 *  2. The MIT License, found at <http://opensource.org/licenses/MIT>.
 */

#ifndef SPIRV_CROSS_COMMON_HPP
#define SPIRV_CROSS_COMMON_HPP

#ifndef SPV_ENABLE_UTILITY_CODE
#define SPV_ENABLE_UTILITY_CODE
#endif
#include "spirv.hpp"

#include "spirv_cross_containers.hpp"
#include "spirv_cross_error_handling.hpp"
#include <functional>

// A bit crude, but allows projects which embed SPIRV-Cross statically to
// effectively hide all the symbols from other projects.
// There is a case where we have:
// - Project A links against SPIRV-Cross statically.
// - Project A links against Project B statically.
// - Project B links against SPIRV-Cross statically (might be a different version).
// This leads to a conflict with extremely bizarre results.
// By overriding the namespace in one of the project builds, we can work around this.
// If SPIRV-Cross is embedded in dynamic libraries,
// prefer using -fvisibility=hidden on GCC/Clang instead.
#ifdef SPIRV_CROSS_NAMESPACE_OVERRIDE
#define SPIRV_CROSS_NAMESPACE SPIRV_CROSS_NAMESPACE_OVERRIDE
#else
#define SPIRV_CROSS_NAMESPACE spirv_cross
#endif

namespace SPIRV_CROSS_NAMESPACE
{
namespace inner
{
template <typename T>
void join_helper(StringStream<> &stream, T &&t)
{
        stream << std::forward<T>(t);
}

template <typename T, typename... Ts>
void join_helper(StringStream<> &stream, T &&t, Ts &&... ts)
{
        stream << std::forward<T>(t);
        join_helper(stream, std::forward<Ts>(ts)...);
}
} // namespace inner

class Bitset
{
public:
        Bitset() = default;
        explicit inline Bitset(uint64_t lower_)
            : lower(lower_)
        {
        }

        inline bool get(uint32_t bit) const
        {
                if (bit < 64)
                        return (lower & (1ull << bit)) != 0;
                else
                        return higher.count(bit) != 0;
        }

        inline void set(uint32_t bit)
        {
                if (bit < 64)
                        lower |= 1ull << bit;
                else
                        higher.insert(bit);
        }

        inline void clear(uint32_t bit)
        {
                if (bit < 64)
                        lower &= ~(1ull << bit);
                else
                        higher.erase(bit);
        }

        inline uint64_t get_lower() const
        {
                return lower;
        }

        inline void reset()
        {
                lower = 0;
                higher.clear();
        }

        inline void merge_and(const Bitset &other)
        {
                lower &= other.lower;
                std::unordered_set<uint32_t> tmp_set;
                for (auto &v : higher)
                        if (other.higher.count(v) != 0)
                                tmp_set.insert(v);
                higher = std::move(tmp_set);
        }

        inline void merge_or(const Bitset &other)
        {
                lower |= other.lower;
                for (auto &v : other.higher)
                        higher.insert(v);
        }

        inline bool operator==(const Bitset &other) const
        {
                if (lower != other.lower)
                        return false;

                if (higher.size() != other.higher.size())
                        return false;

                for (auto &v : higher)
                        if (other.higher.count(v) == 0)
                                return false;

                return true;
        }

        inline bool operator!=(const Bitset &other) const
        {
                return !(*this == other);
        }

        template <typename Op>
        void for_each_bit(const Op &op) const
        {
                // TODO: Add ctz-based iteration.
                for (uint32_t i = 0; i < 64; i++)
                {
                        if (lower & (1ull << i))
                                op(i);
                }

                if (higher.empty())
                        return;

                // Need to enforce an order here for reproducible results,
                // but hitting this path should happen extremely rarely, so having this slow path is fine.
                SmallVector<uint32_t> bits;
                bits.reserve(higher.size());
                for (auto &v : higher)
                        bits.push_back(v);
                std::sort(std::begin(bits), std::end(bits));

                for (auto &v : bits)
                        op(v);
        }

        inline bool empty() const
        {
                return lower == 0 && higher.empty();
        }

private:
        // The most common bits to set are all lower than 64,
        // so optimize for this case. Bits spilling outside 64 go into a slower data structure.
        // In almost all cases, higher data structure will not be used.
        uint64_t lower = 0;
        std::unordered_set<uint32_t> higher;
};

// Helper template to avoid lots of nasty string temporary munging.
template <typename... Ts>
std::string join(Ts &&... ts)
{
        StringStream<> stream;
        inner::join_helper(stream, std::forward<Ts>(ts)...);
        return stream.str();
}

inline std::string merge(const SmallVector<std::string> &list, const char *between = ", ")
{
        StringStream<> stream;
        for (auto &elem : list)
        {
                stream << elem;
                if (&elem != &list.back())
                        stream << between;
        }
        return stream.str();
}

// Make sure we don't accidentally call this with float or doubles with SFINAE.
// Have to use the radix-aware overload.
template <typename T, typename std::enable_if<!std::is_floating_point<T>::value, int>::type = 0>
inline std::string convert_to_string(const T &t)
{
        return std::to_string(t);
}

static inline std::string convert_to_string(int32_t value)
{
        // INT_MIN is ... special on some backends. If we use a decimal literal, and negate it, we
        // could accidentally promote the literal to long first, then negate.
        // To workaround it, emit int(0x80000000) instead.
        if (value == (std::numeric_limits<int32_t>::min)())
                return "int(0x80000000)";
        else
                return std::to_string(value);
}

static inline std::string convert_to_string(int64_t value, const std::string &int64_type, bool long_long_literal_suffix)
{
        // INT64_MIN is ... special on some backends.
        // If we use a decimal literal, and negate it, we might overflow the representable numbers.
        // To workaround it, emit int(0x80000000) instead.
        if (value == (std::numeric_limits<int64_t>::min)())
                return join(int64_type, "(0x8000000000000000u", (long_long_literal_suffix ? "ll" : "l"), ")");
        else
                return std::to_string(value) + (long_long_literal_suffix ? "ll" : "l");
}

// Allow implementations to set a convenient standard precision
#ifndef SPIRV_CROSS_FLT_FMT
#define SPIRV_CROSS_FLT_FMT "%.32g"
#endif

// Disable sprintf and strcat warnings.
// We cannot rely on snprintf and family existing because, ..., MSVC.
#if defined(__clang__) || defined(__GNUC__)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
#elif defined(_MSC_VER)
#pragma warning(push)
#pragma warning(disable : 4996)
#endif

static inline void fixup_radix_point(char *str, char radix_point)
{
        // Setting locales is a very risky business in multi-threaded program,
        // so just fixup locales instead. We only need to care about the radix point.
        if (radix_point != '.')
        {
                while (*str != '\0')
                {
                        if (*str == radix_point)
                                *str = '.';
                        str++;
                }
        }
}

inline std::string convert_to_string(float t, char locale_radix_point)
{
        // std::to_string for floating point values is broken.
        // Fallback to something more sane.
        char buf[64];
        sprintf(buf, SPIRV_CROSS_FLT_FMT, t);
        fixup_radix_point(buf, locale_radix_point);

        // Ensure that the literal is float.
        if (!strchr(buf, '.') && !strchr(buf, 'e'))
                strcat(buf, ".0");
        return buf;
}

inline std::string convert_to_string(double t, char locale_radix_point)
{
        // std::to_string for floating point values is broken.
        // Fallback to something more sane.
        char buf[64];
        sprintf(buf, SPIRV_CROSS_FLT_FMT, t);
        fixup_radix_point(buf, locale_radix_point);

        // Ensure that the literal is float.
        if (!strchr(buf, '.') && !strchr(buf, 'e'))
                strcat(buf, ".0");
        return buf;
}

#if defined(__clang__) || defined(__GNUC__)
#pragma GCC diagnostic pop
#elif defined(_MSC_VER)
#pragma warning(pop)
#endif

class FloatFormatter
{
public:
        virtual ~FloatFormatter() = default;
        virtual std::string format_float(float value) = 0;
        virtual std::string format_double(double value) = 0;
};

template <typename T>
struct ValueSaver
{
        explicit ValueSaver(T &current_)
            : current(current_)
            , saved(current_)
        {
        }

        void release()
        {
                current = saved;
        }

        ~ValueSaver()
        {
                release();
        }

        T &current;
        T saved;
};

struct Instruction
{
        uint16_t op = 0;
        uint16_t count = 0;
        // If offset is 0 (not a valid offset into the instruction stream),
        // we have an instruction stream which is embedded in the object.
        uint32_t offset = 0;
        uint32_t length = 0;

        inline bool is_embedded() const
        {
                return offset == 0;
        }
};

struct EmbeddedInstruction : Instruction
{
        SmallVector<uint32_t> ops;
};

enum Types
{
        TypeNone,
        TypeType,
        TypeVariable,
        TypeConstant,
        TypeFunction,
        TypeFunctionPrototype,
        TypeBlock,
        TypeExtension,
        TypeExpression,
        TypeConstantOp,
        TypeCombinedImageSampler,
        TypeAccessChain,
        TypeUndef,
        TypeString,
        TypeCount
};

template <Types type>
class TypedID;

template <>
class TypedID<TypeNone>
{
public:
        TypedID() = default;
        TypedID(uint32_t id_)
            : id(id_)
        {
        }

        template <Types U>
        TypedID(const TypedID<U> &other)
        {
                *this = other;
        }

        template <Types U>
        TypedID &operator=(const TypedID<U> &other)
        {
                id = uint32_t(other);
                return *this;
        }

        // Implicit conversion to u32 is desired here.
        // As long as we block implicit conversion between TypedID<A> and TypedID<B> we're good.
        operator uint32_t() const
        {
                return id;
        }

        template <Types U>
        operator TypedID<U>() const
        {
                return TypedID<U>(*this);
        }

private:
        uint32_t id = 0;
};

template <Types type>
class TypedID
{
public:
        TypedID() = default;
        TypedID(uint32_t id_)
            : id(id_)
        {
        }

        explicit TypedID(const TypedID<TypeNone> &other)
            : id(uint32_t(other))
        {
        }

        operator uint32_t() const
        {
                return id;
        }

private:
        uint32_t id = 0;
};

using VariableID = TypedID<TypeVariable>;
using TypeID = TypedID<TypeType>;
using ConstantID = TypedID<TypeConstant>;
using FunctionID = TypedID<TypeFunction>;
using BlockID = TypedID<TypeBlock>;
using ID = TypedID<TypeNone>;

// Helper for Variant interface.
struct IVariant
{
        virtual ~IVariant() = default;
        virtual IVariant *clone(ObjectPoolBase *pool) = 0;
        ID self = 0;

protected:
        IVariant() = default;
        IVariant(const IVariant&) = default;
        IVariant &operator=(const IVariant&) = default;
};

#define SPIRV_CROSS_DECLARE_CLONE(T)                                \
        IVariant *clone(ObjectPoolBase *pool) override                  \
        {                                                               \
                return static_cast<ObjectPool<T> *>(pool)->allocate(*this); \
        }

struct SPIRUndef : IVariant
{
        enum
        {
                type = TypeUndef
        };

        explicit SPIRUndef(TypeID basetype_)
            : basetype(basetype_)
        {
        }
        TypeID basetype;

        SPIRV_CROSS_DECLARE_CLONE(SPIRUndef)
};

struct SPIRString : IVariant
{
        enum
        {
                type = TypeString
        };

        explicit SPIRString(std::string str_)
            : str(std::move(str_))
        {
        }

        std::string str;

        SPIRV_CROSS_DECLARE_CLONE(SPIRString)
};

// This type is only used by backends which need to access the combined image and sampler IDs separately after
// the OpSampledImage opcode.
struct SPIRCombinedImageSampler : IVariant
{
        enum
        {
                type = TypeCombinedImageSampler
        };
        SPIRCombinedImageSampler(TypeID type_, VariableID image_, VariableID sampler_)
            : combined_type(type_)
            , image(image_)
            , sampler(sampler_)
        {
        }
        TypeID combined_type;
        VariableID image;
        VariableID sampler;

        SPIRV_CROSS_DECLARE_CLONE(SPIRCombinedImageSampler)
};

struct SPIRConstantOp : IVariant
{
        enum
        {
                type = TypeConstantOp
        };

        SPIRConstantOp(TypeID result_type, spv::Op op, const uint32_t *args, uint32_t length)
            : opcode(op)
            , basetype(result_type)
        {
                arguments.reserve(length);
                for (uint32_t i = 0; i < length; i++)
                        arguments.push_back(args[i]);
        }

        spv::Op opcode;
        SmallVector<uint32_t> arguments;
        TypeID basetype;

        SPIRV_CROSS_DECLARE_CLONE(SPIRConstantOp)
};

struct SPIRType : IVariant
{
        enum
        {
                type = TypeType
        };

        spv::Op op = spv::Op::OpNop;
        explicit SPIRType(spv::Op op_) : op(op_) {}

        enum BaseType
        {
                Unknown,
                Void,
                Boolean,
                SByte,
                UByte,
                Short,
                UShort,
                Int,
                UInt,
                Int64,
                UInt64,
                AtomicCounter,
                Half,
                Float,
                Double,
                Struct,
                Image,
                SampledImage,
                Sampler,
                AccelerationStructure,
                RayQuery,

                // Keep internal types at the end.
                ControlPointArray,
                Interpolant,
                Char,
                // MSL specific type, that is used by 'object'(analog of 'task' from glsl) shader.
                MeshGridProperties
        };

        // Scalar/vector/matrix support.
        BaseType basetype = Unknown;
        uint32_t width = 0;
        uint32_t vecsize = 1;
        uint32_t columns = 1;

        // Arrays, support array of arrays by having a vector of array sizes.
        SmallVector<uint32_t> array;

        // Array elements can be either specialization constants or specialization ops.
        // This array determines how to interpret the array size.
        // If an element is true, the element is a literal,
        // otherwise, it's an expression, which must be resolved on demand.
        // The actual size is not really known until runtime.
        SmallVector<bool> array_size_literal;

        // Pointers
        // Keep track of how many pointer layers we have.
        uint32_t pointer_depth = 0;
        bool pointer = false;
        bool forward_pointer = false;

        spv::StorageClass storage = spv::StorageClassGeneric;

        SmallVector<TypeID> member_types;

        // If member order has been rewritten to handle certain scenarios with Offset,
        // allow codegen to rewrite the index.
        SmallVector<uint32_t> member_type_index_redirection;

        struct ImageType
        {
                TypeID type;
                spv::Dim dim;
                bool depth;
                bool arrayed;
                bool ms;
                uint32_t sampled;
                spv::ImageFormat format;
                spv::AccessQualifier access;
        } image = {};

        // Structs can be declared multiple times if they are used as part of interface blocks.
        // We want to detect this so that we only emit the struct definition once.
        // Since we cannot rely on OpName to be equal, we need to figure out aliases.
        TypeID type_alias = 0;

        // Denotes the type which this type is based on.
        // Allows the backend to traverse how a complex type is built up during access chains.
        TypeID parent_type = 0;

        // Used in backends to avoid emitting members with conflicting names.
        std::unordered_set<std::string> member_name_cache;

        SPIRV_CROSS_DECLARE_CLONE(SPIRType)
};

struct SPIRExtension : IVariant
{
        enum
        {
                type = TypeExtension
        };

        enum Extension
        {
                Unsupported,
                GLSL,
                SPV_debug_info,
                SPV_AMD_shader_ballot,
                SPV_AMD_shader_explicit_vertex_parameter,
                SPV_AMD_shader_trinary_minmax,
                SPV_AMD_gcn_shader,
                NonSemanticDebugPrintf,
                NonSemanticShaderDebugInfo,
                NonSemanticGeneric
        };

        explicit SPIRExtension(Extension ext_)
            : ext(ext_)
        {
        }

        Extension ext;
        SPIRV_CROSS_DECLARE_CLONE(SPIRExtension)
};

// SPIREntryPoint is not a variant since its IDs are used to decorate OpFunction,
// so in order to avoid conflicts, we can't stick them in the ids array.
struct SPIREntryPoint
{
        SPIREntryPoint(FunctionID self_, spv::ExecutionModel execution_model, const std::string &entry_name)
            : self(self_)
            , name(entry_name)
            , orig_name(entry_name)
            , model(execution_model)
        {
        }
        SPIREntryPoint() = default;

        FunctionID self = 0;
        std::string name;
        std::string orig_name;
        SmallVector<VariableID> interface_variables;

        Bitset flags;
        struct WorkgroupSize
        {
                uint32_t x = 0, y = 0, z = 0;
                uint32_t id_x = 0, id_y = 0, id_z = 0;
                uint32_t constant = 0; // Workgroup size can be expressed as a constant/spec-constant instead.
        } workgroup_size;
        uint32_t invocations = 0;
        uint32_t output_vertices = 0;
        uint32_t output_primitives = 0;
        spv::ExecutionModel model = spv::ExecutionModelMax;
        bool geometry_passthrough = false;
};

struct SPIRExpression : IVariant
{
        enum
        {
                type = TypeExpression
        };

        // Only created by the backend target to avoid creating tons of temporaries.
        SPIRExpression(std::string expr, TypeID expression_type_, bool immutable_)
            : expression(std::move(expr))
            , expression_type(expression_type_)
            , immutable(immutable_)
        {
        }

        // If non-zero, prepend expression with to_expression(base_expression).
        // Used in amortizing multiple calls to to_expression()
        // where in certain cases that would quickly force a temporary when not needed.
        ID base_expression = 0;

        std::string expression;
        TypeID expression_type = 0;

        // If this expression is a forwarded load,
        // allow us to reference the original variable.
        ID loaded_from = 0;

        // If this expression will never change, we can avoid lots of temporaries
        // in high level source.
        // An expression being immutable can be speculative,
        // it is assumed that this is true almost always.
        bool immutable = false;

        // Before use, this expression must be transposed.
        // This is needed for targets which don't support row_major layouts.
        bool need_transpose = false;

        // Whether or not this is an access chain expression.
        bool access_chain = false;

        // Whether or not gl_MeshVerticesEXT[].gl_Position (as a whole or .y) is referenced
        bool access_meshlet_position_y = false;

        // A list of expressions which this expression depends on.
        SmallVector<ID> expression_dependencies;

        // Similar as expression dependencies, but does not stop the tracking for force-temporary variables.
        // We need to know the full chain from store back to any SSA variable.
        SmallVector<ID> invariance_dependencies;

        // By reading this expression, we implicitly read these expressions as well.
        // Used by access chain Store and Load since we read multiple expressions in this case.
        SmallVector<ID> implied_read_expressions;

        // The expression was emitted at a certain scope. Lets us track when an expression read means multiple reads.
        uint32_t emitted_loop_level = 0;

        SPIRV_CROSS_DECLARE_CLONE(SPIRExpression)
};

struct SPIRFunctionPrototype : IVariant
{
        enum
        {
                type = TypeFunctionPrototype
        };

        explicit SPIRFunctionPrototype(TypeID return_type_)
            : return_type(return_type_)
        {
        }

        TypeID return_type;
        SmallVector<uint32_t> parameter_types;

        SPIRV_CROSS_DECLARE_CLONE(SPIRFunctionPrototype)
};

struct SPIRBlock : IVariant
{
        enum
        {
                type = TypeBlock
        };

        enum Terminator
        {
                Unknown,
                Direct, // Emit next block directly without a particular condition.

                Select, // Block ends with an if/else block.
                MultiSelect, // Block ends with switch statement.

                Return, // Block ends with return.
                Unreachable, // Noop
                Kill, // Discard
                IgnoreIntersection, // Ray Tracing
                TerminateRay, // Ray Tracing
                EmitMeshTasks // Mesh shaders
        };

        enum Merge
        {
                MergeNone,
                MergeLoop,
                MergeSelection
        };

        enum Hints
        {
                HintNone,
                HintUnroll,
                HintDontUnroll,
                HintFlatten,
                HintDontFlatten
        };

        enum Method
        {
                MergeToSelectForLoop,
                MergeToDirectForLoop,
                MergeToSelectContinueForLoop
        };

        enum ContinueBlockType
        {
                ContinueNone,

                // Continue block is branchless and has at least one instruction.
                ForLoop,

                // Noop continue block.
                WhileLoop,

                // Continue block is conditional.
                DoWhileLoop,

                // Highly unlikely that anything will use this,
                // since it is really awkward/impossible to express in GLSL.
                ComplexLoop
        };

        enum : uint32_t
        {
                NoDominator = 0xffffffffu
        };

        Terminator terminator = Unknown;
        Merge merge = MergeNone;
        Hints hint = HintNone;
        BlockID next_block = 0;
        BlockID merge_block = 0;
        BlockID continue_block = 0;

        ID return_value = 0; // If 0, return nothing (void).
        ID condition = 0;
        BlockID true_block = 0;
        BlockID false_block = 0;
        BlockID default_block = 0;

        // If terminator is EmitMeshTasksEXT.
        struct
        {
                ID groups[3];
                ID payload;
        } mesh = {};

        SmallVector<Instruction> ops;

        struct Phi
        {
                ID local_variable; // flush local variable ...
                BlockID parent; // If we're in from_block and want to branch into this block ...
                VariableID function_variable; // to this function-global "phi" variable first.
        };

        // Before entering this block flush out local variables to magical "phi" variables.
        SmallVector<Phi> phi_variables;

        // Declare these temporaries before beginning the block.
        // Used for handling complex continue blocks which have side effects.
        SmallVector<std::pair<TypeID, ID>> declare_temporary;

        // Declare these temporaries, but only conditionally if this block turns out to be
        // a complex loop header.
        SmallVector<std::pair<TypeID, ID>> potential_declare_temporary;

        struct Case
        {
                uint64_t value;
                BlockID block;
        };
        SmallVector<Case> cases_32bit;
        SmallVector<Case> cases_64bit;

        // If we have tried to optimize code for this block but failed,
        // keep track of this.
        bool disable_block_optimization = false;

        // If the continue block is complex, fallback to "dumb" for loops.
        bool complex_continue = false;

        // Do we need a ladder variable to defer breaking out of a loop construct after a switch block?
        bool need_ladder_break = false;

        // If marked, we have explicitly handled Phi from this block, so skip any flushes related to that on a branch.
        // Used to handle an edge case with switch and case-label fallthrough where fall-through writes to Phi.
        BlockID ignore_phi_from_block = 0;

        // The dominating block which this block might be within.
        // Used in continue; blocks to determine if we really need to write continue.
        BlockID loop_dominator = 0;

        // All access to these variables are dominated by this block,
        // so before branching anywhere we need to make sure that we declare these variables.
        SmallVector<VariableID> dominated_variables;

        // These are variables which should be declared in a for loop header, if we
        // fail to use a classic for-loop,
        // we remove these variables, and fall back to regular variables outside the loop.
        SmallVector<VariableID> loop_variables;

        // Some expressions are control-flow dependent, i.e. any instruction which relies on derivatives or
        // sub-group-like operations.
        // Make sure that we only use these expressions in the original block.
        SmallVector<ID> invalidate_expressions;

        SPIRV_CROSS_DECLARE_CLONE(SPIRBlock)
};

struct SPIRFunction : IVariant
{
        enum
        {
                type = TypeFunction
        };

        SPIRFunction(TypeID return_type_, TypeID function_type_)
            : return_type(return_type_)
            , function_type(function_type_)
        {
        }

        struct Parameter
        {
                TypeID type;
                ID id;
                uint32_t read_count;
                uint32_t write_count;

                // Set to true if this parameter aliases a global variable,
                // used mostly in Metal where global variables
                // have to be passed down to functions as regular arguments.
                // However, for this kind of variable, we should not care about
                // read and write counts as access to the function arguments
                // is not local to the function in question.
                bool alias_global_variable;
        };

        // When calling a function, and we're remapping separate image samplers,
        // resolve these arguments into combined image samplers and pass them
        // as additional arguments in this order.
        // It gets more complicated as functions can pull in their own globals
        // and combine them with parameters,
        // so we need to distinguish if something is local parameter index
        // or a global ID.
        struct CombinedImageSamplerParameter
        {
                VariableID id;
                VariableID image_id;
                VariableID sampler_id;
                bool global_image;
                bool global_sampler;
                bool depth;
        };

        TypeID return_type;
        TypeID function_type;
        SmallVector<Parameter> arguments;

        // Can be used by backends to add magic arguments.
        // Currently used by combined image/sampler implementation.

        SmallVector<Parameter> shadow_arguments;
        SmallVector<VariableID> local_variables;
        BlockID entry_block = 0;
        SmallVector<BlockID> blocks;
        SmallVector<CombinedImageSamplerParameter> combined_parameters;

        struct EntryLine
        {
                uint32_t file_id = 0;
                uint32_t line_literal = 0;
        };
        EntryLine entry_line;

        void add_local_variable(VariableID id)
        {
                local_variables.push_back(id);
        }

        void add_parameter(TypeID parameter_type, ID id, bool alias_global_variable = false)
        {
                // Arguments are read-only until proven otherwise.
                arguments.push_back({ parameter_type, id, 0u, 0u, alias_global_variable });
        }

        // Hooks to be run when the function returns.
        // Mostly used for lowering internal data structures onto flattened structures.
        // Need to defer this, because they might rely on things which change during compilation.
        // Intentionally not a small vector, this one is rare, and std::function can be large.
        Vector<std::function<void()>> fixup_hooks_out;

        // Hooks to be run when the function begins.
        // Mostly used for populating internal data structures from flattened structures.
        // Need to defer this, because they might rely on things which change during compilation.
        // Intentionally not a small vector, this one is rare, and std::function can be large.
        Vector<std::function<void()>> fixup_hooks_in;

        // On function entry, make sure to copy a constant array into thread addr space to work around
        // the case where we are passing a constant array by value to a function on backends which do not
        // consider arrays value types.
        SmallVector<ID> constant_arrays_needed_on_stack;

        bool active = false;
        bool flush_undeclared = true;
        bool do_combined_parameters = true;

        SPIRV_CROSS_DECLARE_CLONE(SPIRFunction)
};

struct SPIRAccessChain : IVariant
{
        enum
        {
                type = TypeAccessChain
        };

        SPIRAccessChain(TypeID basetype_, spv::StorageClass storage_, std::string base_, std::string dynamic_index_,
                        int32_t static_index_)
            : basetype(basetype_)
            , storage(storage_)
            , base(std::move(base_))
            , dynamic_index(std::move(dynamic_index_))
            , static_index(static_index_)
        {
        }

        // The access chain represents an offset into a buffer.
        // Some backends need more complicated handling of access chains to be able to use buffers, like HLSL
        // which has no usable buffer type ala GLSL SSBOs.
        // StructuredBuffer is too limited, so our only option is to deal with ByteAddressBuffer which works with raw addresses.

        TypeID basetype;
        spv::StorageClass storage;
        std::string base;
        std::string dynamic_index;
        int32_t static_index;

        VariableID loaded_from = 0;
        uint32_t matrix_stride = 0;
        uint32_t array_stride = 0;
        bool row_major_matrix = false;
        bool immutable = false;

        // By reading this expression, we implicitly read these expressions as well.
        // Used by access chain Store and Load since we read multiple expressions in this case.
        SmallVector<ID> implied_read_expressions;

        SPIRV_CROSS_DECLARE_CLONE(SPIRAccessChain)
};

struct SPIRVariable : IVariant
{
        enum
        {
                type = TypeVariable
        };

        SPIRVariable() = default;
        SPIRVariable(TypeID basetype_, spv::StorageClass storage_, ID initializer_ = 0, VariableID basevariable_ = 0)
            : basetype(basetype_)
            , storage(storage_)
            , initializer(initializer_)
            , basevariable(basevariable_)
        {
        }

        TypeID basetype = 0;
        spv::StorageClass storage = spv::StorageClassGeneric;
        uint32_t decoration = 0;
        ID initializer = 0;
        VariableID basevariable = 0;

        SmallVector<uint32_t> dereference_chain;
        bool compat_builtin = false;

        // If a variable is shadowed, we only statically assign to it
        // and never actually emit a statement for it.
        // When we read the variable as an expression, just forward
        // shadowed_id as the expression.
        bool statically_assigned = false;
        ID static_expression = 0;

        // Temporaries which can remain forwarded as long as this variable is not modified.
        SmallVector<ID> dependees;

        bool deferred_declaration = false;
        bool phi_variable = false;

        // Used to deal with Phi variable flushes. See flush_phi().
        bool allocate_temporary_copy = false;

        bool remapped_variable = false;
        uint32_t remapped_components = 0;

        // The block which dominates all access to this variable.
        BlockID dominator = 0;
        // If true, this variable is a loop variable, when accessing the variable
        // outside a loop,
        // we should statically forward it.
        bool loop_variable = false;
        // Set to true while we're inside the for loop.
        bool loop_variable_enable = false;

        // Used to find global LUTs
        bool is_written_to = false;

        SPIRFunction::Parameter *parameter = nullptr;

        SPIRV_CROSS_DECLARE_CLONE(SPIRVariable)
};

struct SPIRConstant : IVariant
{
        enum
        {
                type = TypeConstant
        };

        union Constant
        {
                uint32_t u32;
                int32_t i32;
                float f32;

                uint64_t u64;
                int64_t i64;
                double f64;
        };

        struct ConstantVector
        {
                Constant r[4];
                // If != 0, this element is a specialization constant, and we should keep track of it as such.
                ID id[4];
                uint32_t vecsize = 1;

                ConstantVector()
                {
                        memset(r, 0, sizeof(r));
                }
        };

        struct ConstantMatrix
        {
                ConstantVector c[4];
                // If != 0, this column is a specialization constant, and we should keep track of it as such.
                ID id[4];
                uint32_t columns = 1;
        };

        static inline float f16_to_f32(uint16_t u16_value)
        {
                // Based on the GLM implementation.
                int s = (u16_value >> 15) & 0x1;
                int e = (u16_value >> 10) & 0x1f;
                int m = (u16_value >> 0) & 0x3ff;

                union
                {
                        float f32;
                        uint32_t u32;
                } u;

                if (e == 0)
                {
                        if (m == 0)
                        {
                                u.u32 = uint32_t(s) << 31;
                                return u.f32;
                        }
                        else
                        {
                                while ((m & 0x400) == 0)
                                {
                                        m <<= 1;
                                        e--;
                                }

                                e++;
                                m &= ~0x400;
                        }
                }
                else if (e == 31)
                {
                        if (m == 0)
                        {
                                u.u32 = (uint32_t(s) << 31) | 0x7f800000u;
                                return u.f32;
                        }
                        else
                        {
                                u.u32 = (uint32_t(s) << 31) | 0x7f800000u | (m << 13);
                                return u.f32;
                        }
                }

                e += 127 - 15;
                m <<= 13;
                u.u32 = (uint32_t(s) << 31) | (e << 23) | m;
                return u.f32;
        }

        inline uint32_t specialization_constant_id(uint32_t col, uint32_t row) const
        {
                return m.c[col].id[row];
        }

        inline uint32_t specialization_constant_id(uint32_t col) const
        {
                return m.id[col];
        }

        inline uint32_t scalar(uint32_t col = 0, uint32_t row = 0) const
        {
                return m.c[col].r[row].u32;
        }

        inline int16_t scalar_i16(uint32_t col = 0, uint32_t row = 0) const
        {
                return int16_t(m.c[col].r[row].u32 & 0xffffu);
        }

        inline uint16_t scalar_u16(uint32_t col = 0, uint32_t row = 0) const
        {
                return uint16_t(m.c[col].r[row].u32 & 0xffffu);
        }

        inline int8_t scalar_i8(uint32_t col = 0, uint32_t row = 0) const
        {
                return int8_t(m.c[col].r[row].u32 & 0xffu);
        }

        inline uint8_t scalar_u8(uint32_t col = 0, uint32_t row = 0) const
        {
                return uint8_t(m.c[col].r[row].u32 & 0xffu);
        }

        inline float scalar_f16(uint32_t col = 0, uint32_t row = 0) const
        {
                return f16_to_f32(scalar_u16(col, row));
        }

        inline float scalar_f32(uint32_t col = 0, uint32_t row = 0) const
        {
                return m.c[col].r[row].f32;
        }

        inline int32_t scalar_i32(uint32_t col = 0, uint32_t row = 0) const
        {
                return m.c[col].r[row].i32;
        }

        inline double scalar_f64(uint32_t col = 0, uint32_t row = 0) const
        {
                return m.c[col].r[row].f64;
        }

        inline int64_t scalar_i64(uint32_t col = 0, uint32_t row = 0) const
        {
                return m.c[col].r[row].i64;
        }

        inline uint64_t scalar_u64(uint32_t col = 0, uint32_t row = 0) const
        {
                return m.c[col].r[row].u64;
        }

        inline const ConstantVector &vector() const
        {
                return m.c[0];
        }

        inline uint32_t vector_size() const
        {
                return m.c[0].vecsize;
        }

        inline uint32_t columns() const
        {
                return m.columns;
        }

        inline void make_null(const SPIRType &constant_type_)
        {
                m = {};
                m.columns = constant_type_.columns;
                for (auto &c : m.c)
                        c.vecsize = constant_type_.vecsize;
        }

        inline bool constant_is_null() const
        {
                if (specialization)
                        return false;
                if (!subconstants.empty())
                        return false;

                for (uint32_t col = 0; col < columns(); col++)
                        for (uint32_t row = 0; row < vector_size(); row++)
                                if (scalar_u64(col, row) != 0)
                                        return false;

                return true;
        }

        explicit SPIRConstant(uint32_t constant_type_)
            : constant_type(constant_type_)
        {
        }

        SPIRConstant() = default;

        SPIRConstant(TypeID constant_type_, const uint32_t *elements, uint32_t num_elements, bool specialized)
            : constant_type(constant_type_)
            , specialization(specialized)
        {
                subconstants.reserve(num_elements);
                for (uint32_t i = 0; i < num_elements; i++)
                        subconstants.push_back(elements[i]);
                specialization = specialized;
        }

        // Construct scalar (32-bit).
        SPIRConstant(TypeID constant_type_, uint32_t v0, bool specialized)
            : constant_type(constant_type_)
            , specialization(specialized)
        {
                m.c[0].r[0].u32 = v0;
                m.c[0].vecsize = 1;
                m.columns = 1;
        }

        // Construct scalar (64-bit).
        SPIRConstant(TypeID constant_type_, uint64_t v0, bool specialized)
            : constant_type(constant_type_)
            , specialization(specialized)
        {
                m.c[0].r[0].u64 = v0;
                m.c[0].vecsize = 1;
                m.columns = 1;
        }

        // Construct vectors and matrices.
        SPIRConstant(TypeID constant_type_, const SPIRConstant *const *vector_elements, uint32_t num_elements,
                     bool specialized)
            : constant_type(constant_type_)
            , specialization(specialized)
        {
                bool matrix = vector_elements[0]->m.c[0].vecsize > 1;

                if (matrix)
                {
                        m.columns = num_elements;

                        for (uint32_t i = 0; i < num_elements; i++)
                        {
                                m.c[i] = vector_elements[i]->m.c[0];
                                if (vector_elements[i]->specialization)
                                        m.id[i] = vector_elements[i]->self;
                        }
                }
                else
                {
                        m.c[0].vecsize = num_elements;
                        m.columns = 1;

                        for (uint32_t i = 0; i < num_elements; i++)
                        {
                                m.c[0].r[i] = vector_elements[i]->m.c[0].r[0];
                                if (vector_elements[i]->specialization)
                                        m.c[0].id[i] = vector_elements[i]->self;
                        }
                }
        }

        TypeID constant_type = 0;
        ConstantMatrix m;

        // If this constant is a specialization constant (i.e. created with OpSpecConstant*).
        bool specialization = false;
        // If this constant is used as an array length which creates specialization restrictions on some backends.
        bool is_used_as_array_length = false;

        // If true, this is a LUT, and should always be declared in the outer scope.
        bool is_used_as_lut = false;

        // For composites which are constant arrays, etc.
        SmallVector<ConstantID> subconstants;

        // Non-Vulkan GLSL, HLSL and sometimes MSL emits defines for each specialization constant,
        // and uses them to initialize the constant. This allows the user
        // to still be able to specialize the value by supplying corresponding
        // preprocessor directives before compiling the shader.
        std::string specialization_constant_macro_name;

        SPIRV_CROSS_DECLARE_CLONE(SPIRConstant)
};

// Variants have a very specific allocation scheme.
struct ObjectPoolGroup
{
        std::unique_ptr<ObjectPoolBase> pools[TypeCount];
};

class Variant
{
public:
        explicit Variant(ObjectPoolGroup *group_)
            : group(group_)
        {
        }

        ~Variant()
        {
                if (holder)
                        group->pools[type]->deallocate_opaque(holder);
        }

        // Marking custom move constructor as noexcept is important.
        Variant(Variant &&other) SPIRV_CROSS_NOEXCEPT
        {
                *this = std::move(other);
        }

        // We cannot copy from other variant without our own pool group.
        // Have to explicitly copy.
        Variant(const Variant &variant) = delete;

        // Marking custom move constructor as noexcept is important.
        Variant &operator=(Variant &&other) SPIRV_CROSS_NOEXCEPT
        {
                if (this != &other)
                {
                        if (holder)
                                group->pools[type]->deallocate_opaque(holder);
                        holder = other.holder;
                        group = other.group;
                        type = other.type;
                        allow_type_rewrite = other.allow_type_rewrite;

                        other.holder = nullptr;
                        other.type = TypeNone;
                }
                return *this;
        }

        // This copy/clone should only be called in the Compiler constructor.
        // If this is called inside ::compile(), we invalidate any references we took higher in the stack.
        // This should never happen.
        Variant &operator=(const Variant &other)
        {
//#define SPIRV_CROSS_COPY_CONSTRUCTOR_SANITIZE
#ifdef SPIRV_CROSS_COPY_CONSTRUCTOR_SANITIZE
                abort();
#endif
                if (this != &other)
                {
                        if (holder)
                                group->pools[type]->deallocate_opaque(holder);

                        if (other.holder)
                                holder = other.holder->clone(group->pools[other.type].get());
                        else
                                holder = nullptr;

                        type = other.type;
                        allow_type_rewrite = other.allow_type_rewrite;
                }
                return *this;
        }

        void set(IVariant *val, Types new_type)
        {
                if (holder)
                        group->pools[type]->deallocate_opaque(holder);
                holder = nullptr;

                if (!allow_type_rewrite && type != TypeNone && type != new_type)
                {
                        if (val)
                                group->pools[new_type]->deallocate_opaque(val);
                        SPIRV_CROSS_THROW("Overwriting a variant with new type.");
                }

                holder = val;
                type = new_type;
                allow_type_rewrite = false;
        }

        template <typename T, typename... Ts>
        T *allocate_and_set(Types new_type, Ts &&... ts)
        {
                T *val = static_cast<ObjectPool<T> &>(*group->pools[new_type]).allocate(std::forward<Ts>(ts)...);
                set(val, new_type);
                return val;
        }

        template <typename T>
        T &get()
        {
                if (!holder)
                        SPIRV_CROSS_THROW("nullptr");
                if (static_cast<Types>(T::type) != type)
                        SPIRV_CROSS_THROW("Bad cast");
                return *static_cast<T *>(holder);
        }

        template <typename T>
        const T &get() const
        {
                if (!holder)
                        SPIRV_CROSS_THROW("nullptr");
                if (static_cast<Types>(T::type) != type)
                        SPIRV_CROSS_THROW("Bad cast");
                return *static_cast<const T *>(holder);
        }

        Types get_type() const
        {
                return type;
        }

        ID get_id() const
        {
                return holder ? holder->self : ID(0);
        }

        bool empty() const
        {
                return !holder;
        }

        void reset()
        {
                if (holder)
                        group->pools[type]->deallocate_opaque(holder);
                holder = nullptr;
                type = TypeNone;
        }

        void set_allow_type_rewrite()
        {
                allow_type_rewrite = true;
        }

private:
        ObjectPoolGroup *group = nullptr;
        IVariant *holder = nullptr;
        Types type = TypeNone;
        bool allow_type_rewrite = false;
};

template <typename T>
T &variant_get(Variant &var)
{
        return var.get<T>();
}

template <typename T>
const T &variant_get(const Variant &var)
{
        return var.get<T>();
}

template <typename T, typename... P>
T &variant_set(Variant &var, P &&... args)
{
        auto *ptr = var.allocate_and_set<T>(static_cast<Types>(T::type), std::forward<P>(args)...);
        return *ptr;
}

struct AccessChainMeta
{
        uint32_t storage_physical_type = 0;
        bool need_transpose = false;
        bool storage_is_packed = false;
        bool storage_is_invariant = false;
        bool flattened_struct = false;
        bool relaxed_precision = false;
        bool access_meshlet_position_y = false;
        bool chain_is_builtin = false;
        spv::BuiltIn builtin = {};
};

enum ExtendedDecorations
{
        // Marks if a buffer block is re-packed, i.e. member declaration might be subject to PhysicalTypeID remapping and padding.
        SPIRVCrossDecorationBufferBlockRepacked = 0,

        // A type in a buffer block might be declared with a different physical type than the logical type.
        // If this is not set, PhysicalTypeID == the SPIR-V type as declared.
        SPIRVCrossDecorationPhysicalTypeID,

        // Marks if the physical type is to be declared with tight packing rules, i.e. packed_floatN on MSL and friends.
        // If this is set, PhysicalTypeID might also be set. It can be set to same as logical type if all we're doing
        // is converting float3 to packed_float3 for example.
        // If this is marked on a struct, it means the struct itself must use only Packed types for all its members.
        SPIRVCrossDecorationPhysicalTypePacked,

        // The padding in bytes before declaring this struct member.
        // If used on a struct type, marks the target size of a struct.
        SPIRVCrossDecorationPaddingTarget,

        SPIRVCrossDecorationInterfaceMemberIndex,
        SPIRVCrossDecorationInterfaceOrigID,
        SPIRVCrossDecorationResourceIndexPrimary,
        // Used for decorations like resource indices for samplers when part of combined image samplers.
        // A variable might need to hold two resource indices in this case.
        SPIRVCrossDecorationResourceIndexSecondary,
        // Used for resource indices for multiplanar images when part of combined image samplers.
        SPIRVCrossDecorationResourceIndexTertiary,
        SPIRVCrossDecorationResourceIndexQuaternary,

        // Marks a buffer block for using explicit offsets (GLSL/HLSL).
        SPIRVCrossDecorationExplicitOffset,

        // Apply to a variable in the Input storage class; marks it as holding the base group passed to vkCmdDispatchBase(),
        // or the base vertex and instance indices passed to vkCmdDrawIndexed().
        // In MSL, this is used to adjust the WorkgroupId and GlobalInvocationId variables in compute shaders,
        // and to hold the BaseVertex and BaseInstance variables in vertex shaders.
        SPIRVCrossDecorationBuiltInDispatchBase,

        // Apply to a variable that is a function parameter; marks it as being a "dynamic"
        // combined image-sampler. In MSL, this is used when a function parameter might hold
        // either a regular combined image-sampler or one that has an attached sampler
        // Y'CbCr conversion.
        SPIRVCrossDecorationDynamicImageSampler,

        // Apply to a variable in the Input storage class; marks it as holding the size of the stage
        // input grid.
        // In MSL, this is used to hold the vertex and instance counts in a tessellation pipeline
        // vertex shader.
        SPIRVCrossDecorationBuiltInStageInputSize,

        // Apply to any access chain of a tessellation I/O variable; stores the type of the sub-object
        // that was chained to, as recorded in the input variable itself. This is used in case the pointer
        // is itself used as the base of an access chain, to calculate the original type of the sub-object
        // chained to, in case a swizzle needs to be applied. This should not happen normally with valid
        // SPIR-V, but the MSL backend can change the type of input variables, necessitating the
        // addition of swizzles to keep the generated code compiling.
        SPIRVCrossDecorationTessIOOriginalInputTypeID,

        // Apply to any access chain of an interface variable used with pull-model interpolation, where the variable is a
        // vector but the resulting pointer is a scalar; stores the component index that is to be accessed by the chain.
        // This is used when emitting calls to interpolation functions on the chain in MSL: in this case, the component
        // must be applied to the result, since pull-model interpolants in MSL cannot be swizzled directly, but the
        // results of interpolation can.
        SPIRVCrossDecorationInterpolantComponentExpr,

        // Apply to any struct type that is used in the Workgroup storage class.
        // This causes matrices in MSL prior to Metal 3.0 to be emitted using a special
        // class that is convertible to the standard matrix type, to work around the
        // lack of constructors in the 'threadgroup' address space.
        SPIRVCrossDecorationWorkgroupStruct,

        SPIRVCrossDecorationOverlappingBinding,

        SPIRVCrossDecorationCount
};

struct Meta
{
        struct Decoration
        {
                std::string alias;
                std::string qualified_alias;
                std::string hlsl_semantic;
                std::string user_type;
                Bitset decoration_flags;
                spv::BuiltIn builtin_type = spv::BuiltInMax;
                uint32_t location = 0;
                uint32_t component = 0;
                uint32_t set = 0;
                uint32_t binding = 0;
                uint32_t offset = 0;
                uint32_t xfb_buffer = 0;
                uint32_t xfb_stride = 0;
                uint32_t stream = 0;
                uint32_t array_stride = 0;
                uint32_t matrix_stride = 0;
                uint32_t input_attachment = 0;
                uint32_t spec_id = 0;
                uint32_t index = 0;
                spv::FPRoundingMode fp_rounding_mode = spv::FPRoundingModeMax;
                bool builtin = false;
                bool qualified_alias_explicit_override = false;

                struct Extended
                {
                        Extended()
                        {
                                // MSVC 2013 workaround to init like this.
                                for (auto &v : values)
                                        v = 0;
                        }

                        Bitset flags;
                        uint32_t values[SPIRVCrossDecorationCount];
                } extended;
        };

        Decoration decoration;

        // Intentionally not a SmallVector. Decoration is large and somewhat rare.
        Vector<Decoration> members;

        std::unordered_map<uint32_t, uint32_t> decoration_word_offset;

        // For SPV_GOOGLE_hlsl_functionality1.
        bool hlsl_is_magic_counter_buffer = false;
        // ID for the sibling counter buffer.
        uint32_t hlsl_magic_counter_buffer = 0;
};

// A user callback that remaps the type of any variable.
// var_name is the declared name of the variable.
// name_of_type is the textual name of the type which will be used in the code unless written to by the callback.
using VariableTypeRemapCallback =
    std::function<void(const SPIRType &type, const std::string &var_name, std::string &name_of_type)>;

class Hasher
{
public:
        inline void u32(uint32_t value)
        {
                h = (h * 0x100000001b3ull) ^ value;
        }

        inline uint64_t get() const
        {
                return h;
        }

private:
        uint64_t h = 0xcbf29ce484222325ull;
};

static inline bool type_is_floating_point(const SPIRType &type)
{
        return type.basetype == SPIRType::Half || type.basetype == SPIRType::Float || type.basetype == SPIRType::Double;
}

static inline bool type_is_integral(const SPIRType &type)
{
        return type.basetype == SPIRType::SByte || type.basetype == SPIRType::UByte || type.basetype == SPIRType::Short ||
               type.basetype == SPIRType::UShort || type.basetype == SPIRType::Int || type.basetype == SPIRType::UInt ||
               type.basetype == SPIRType::Int64 || type.basetype == SPIRType::UInt64;
}

static inline SPIRType::BaseType to_signed_basetype(uint32_t width)
{
        switch (width)
        {
        case 8:
                return SPIRType::SByte;
        case 16:
                return SPIRType::Short;
        case 32:
                return SPIRType::Int;
        case 64:
                return SPIRType::Int64;
        default:
                SPIRV_CROSS_THROW("Invalid bit width.");
        }
}

static inline SPIRType::BaseType to_unsigned_basetype(uint32_t width)
{
        switch (width)
        {
        case 8:
                return SPIRType::UByte;
        case 16:
                return SPIRType::UShort;
        case 32:
                return SPIRType::UInt;
        case 64:
                return SPIRType::UInt64;
        default:
                SPIRV_CROSS_THROW("Invalid bit width.");
        }
}

// Returns true if an arithmetic operation does not change behavior depending on signedness.
static inline bool opcode_is_sign_invariant(spv::Op opcode)
{
        switch (opcode)
        {
        case spv::OpIEqual:
        case spv::OpINotEqual:
        case spv::OpISub:
        case spv::OpIAdd:
        case spv::OpIMul:
        case spv::OpShiftLeftLogical:
        case spv::OpBitwiseOr:
        case spv::OpBitwiseXor:
        case spv::OpBitwiseAnd:
                return true;

        default:
                return false;
        }
}

static inline bool opcode_can_promote_integer_implicitly(spv::Op opcode)
{
        switch (opcode)
        {
        case spv::OpSNegate:
        case spv::OpNot:
        case spv::OpBitwiseAnd:
        case spv::OpBitwiseOr:
        case spv::OpBitwiseXor:
        case spv::OpShiftLeftLogical:
        case spv::OpShiftRightLogical:
        case spv::OpShiftRightArithmetic:
        case spv::OpIAdd:
        case spv::OpISub:
        case spv::OpIMul:
        case spv::OpSDiv:
        case spv::OpUDiv:
        case spv::OpSRem:
        case spv::OpUMod:
        case spv::OpSMod:
                return true;

        default:
                return false;
        }
}

struct SetBindingPair
{
        uint32_t desc_set;
        uint32_t binding;

        inline bool operator==(const SetBindingPair &other) const
        {
                return desc_set == other.desc_set && binding == other.binding;
        }

        inline bool operator<(const SetBindingPair &other) const
        {
                return desc_set < other.desc_set || (desc_set == other.desc_set && binding < other.binding);
        }
};

struct LocationComponentPair
{
        uint32_t location;
        uint32_t component;

        inline bool operator==(const LocationComponentPair &other) const
        {
                return location == other.location && component == other.component;
        }

        inline bool operator<(const LocationComponentPair &other) const
        {
                return location < other.location || (location == other.location && component < other.component);
        }
};

struct StageSetBinding
{
        spv::ExecutionModel model;
        uint32_t desc_set;
        uint32_t binding;

        inline bool operator==(const StageSetBinding &other) const
        {
                return model == other.model && desc_set == other.desc_set && binding == other.binding;
        }
};

struct InternalHasher
{
        inline size_t operator()(const SetBindingPair &value) const
        {
                // Quality of hash doesn't really matter here.
                auto hash_set = std::hash<uint32_t>()(value.desc_set);
                auto hash_binding = std::hash<uint32_t>()(value.binding);
                return (hash_set * 0x10001b31) ^ hash_binding;
        }

        inline size_t operator()(const LocationComponentPair &value) const
        {
                // Quality of hash doesn't really matter here.
                auto hash_set = std::hash<uint32_t>()(value.location);
                auto hash_binding = std::hash<uint32_t>()(value.component);
                return (hash_set * 0x10001b31) ^ hash_binding;
        }

        inline size_t operator()(const StageSetBinding &value) const
        {
                // Quality of hash doesn't really matter here.
                auto hash_model = std::hash<uint32_t>()(value.model);
                auto hash_set = std::hash<uint32_t>()(value.desc_set);
                auto tmp_hash = (hash_model * 0x10001b31) ^ hash_set;
                return (tmp_hash * 0x10001b31) ^ value.binding;
        }
};

// Special constant used in a {MSL,HLSL}ResourceBinding desc_set
// element to indicate the bindings for the push constants.
static const uint32_t ResourceBindingPushConstantDescriptorSet = ~(0u);

// Special constant used in a {MSL,HLSL}ResourceBinding binding
// element to indicate the bindings for the push constants.
static const uint32_t ResourceBindingPushConstantBinding = 0;
} // namespace SPIRV_CROSS_NAMESPACE

namespace std
{
template <SPIRV_CROSS_NAMESPACE::Types type>
struct hash<SPIRV_CROSS_NAMESPACE::TypedID<type>>
{
        size_t operator()(const SPIRV_CROSS_NAMESPACE::TypedID<type> &value) const
        {
                return std::hash<uint32_t>()(value);
        }
};
} // namespace std

#endif