Program Listing for File spirv_msl.hpp

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/*
 * Copyright 2016-2021 The Brenwill Workshop Ltd.
 * 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_MSL_HPP
#define SPIRV_CROSS_MSL_HPP

#include "spirv_glsl.hpp"
#include <map>
#include <set>
#include <stddef.h>
#include <unordered_map>
#include <unordered_set>

namespace SPIRV_CROSS_NAMESPACE
{

// Indicates the format of a shader interface variable. Currently limited to specifying
// if the input is an 8-bit unsigned integer, 16-bit unsigned integer, or
// some other format.
enum MSLShaderVariableFormat
{
    MSL_SHADER_VARIABLE_FORMAT_OTHER = 0,
    MSL_SHADER_VARIABLE_FORMAT_UINT8 = 1,
    MSL_SHADER_VARIABLE_FORMAT_UINT16 = 2,
    MSL_SHADER_VARIABLE_FORMAT_ANY16 = 3,
    MSL_SHADER_VARIABLE_FORMAT_ANY32 = 4,

    // Deprecated aliases.
    MSL_VERTEX_FORMAT_OTHER = MSL_SHADER_VARIABLE_FORMAT_OTHER,
    MSL_VERTEX_FORMAT_UINT8 = MSL_SHADER_VARIABLE_FORMAT_UINT8,
    MSL_VERTEX_FORMAT_UINT16 = MSL_SHADER_VARIABLE_FORMAT_UINT16,
    MSL_SHADER_INPUT_FORMAT_OTHER = MSL_SHADER_VARIABLE_FORMAT_OTHER,
    MSL_SHADER_INPUT_FORMAT_UINT8 = MSL_SHADER_VARIABLE_FORMAT_UINT8,
    MSL_SHADER_INPUT_FORMAT_UINT16 = MSL_SHADER_VARIABLE_FORMAT_UINT16,
    MSL_SHADER_INPUT_FORMAT_ANY16 = MSL_SHADER_VARIABLE_FORMAT_ANY16,
    MSL_SHADER_INPUT_FORMAT_ANY32 = MSL_SHADER_VARIABLE_FORMAT_ANY32,

    MSL_SHADER_VARIABLE_FORMAT_INT_MAX = 0x7fffffff
};

// Indicates the rate at which a variable changes value, one of: per-vertex,
// per-primitive, or per-patch.
enum MSLShaderVariableRate
{
    MSL_SHADER_VARIABLE_RATE_PER_VERTEX = 0,
    MSL_SHADER_VARIABLE_RATE_PER_PRIMITIVE = 1,
    MSL_SHADER_VARIABLE_RATE_PER_PATCH = 2,

    MSL_SHADER_VARIABLE_RATE_INT_MAX = 0x7fffffff,
};

// Defines MSL characteristics of a shader interface variable at a particular location.
// After compilation, it is possible to query whether or not this location was used.
// If vecsize is nonzero, it must be greater than or equal to the vecsize declared in the shader,
// or behavior is undefined.
struct MSLShaderInterfaceVariable
{
    uint32_t location = 0;
    uint32_t component = 0;
    MSLShaderVariableFormat format = MSL_SHADER_VARIABLE_FORMAT_OTHER;
    spv::BuiltIn builtin = spv::BuiltInMax;
    uint32_t vecsize = 0;
    MSLShaderVariableRate rate = MSL_SHADER_VARIABLE_RATE_PER_VERTEX;
};

// Matches the binding index of a MSL resource for a binding within a descriptor set.
// Taken together, the stage, desc_set and binding combine to form a reference to a resource
// descriptor used in a particular shading stage. The count field indicates the number of
// resources consumed by this binding, if the binding represents an array of resources.
// If the resource array is a run-time-sized array, which are legal in GLSL or SPIR-V, this value
// will be used to declare the array size in MSL, which does not support run-time-sized arrays.
// If pad_argument_buffer_resources is enabled, the base_type and count values are used to
// specify the base type and array size of the resource in the argument buffer, if that resource
// is not defined and used by the shader. With pad_argument_buffer_resources enabled, this
// information will be used to pad the argument buffer structure, in order to align that
// structure consistently for all uses, across all shaders, of the descriptor set represented
// by the arugment buffer. If pad_argument_buffer_resources is disabled, base_type does not
// need to be populated, and if the resource is also not a run-time sized array, the count
// field does not need to be populated.
// If using MSL 2.0 argument buffers, the descriptor set is not marked as a discrete descriptor set,
// and (for iOS only) the resource is not a storage image (sampled != 2), the binding reference we
// remap to will become an [[id(N)]] attribute within the "descriptor set" argument buffer structure.
// For resources which are bound in the "classic" MSL 1.0 way or discrete descriptors, the remap will
// become a [[buffer(N)]], [[texture(N)]] or [[sampler(N)]] depending on the resource types used.
struct MSLResourceBinding
{
    spv::ExecutionModel stage = spv::ExecutionModelMax;
    SPIRType::BaseType basetype = SPIRType::Unknown;
    uint32_t desc_set = 0;
    uint32_t binding = 0;
    uint32_t count = 0;
    uint32_t msl_buffer = 0;
    uint32_t msl_texture = 0;
    uint32_t msl_sampler = 0;
};

enum MSLSamplerCoord
{
    MSL_SAMPLER_COORD_NORMALIZED = 0,
    MSL_SAMPLER_COORD_PIXEL = 1,
    MSL_SAMPLER_INT_MAX = 0x7fffffff
};

enum MSLSamplerFilter
{
    MSL_SAMPLER_FILTER_NEAREST = 0,
    MSL_SAMPLER_FILTER_LINEAR = 1,
    MSL_SAMPLER_FILTER_INT_MAX = 0x7fffffff
};

enum MSLSamplerMipFilter
{
    MSL_SAMPLER_MIP_FILTER_NONE = 0,
    MSL_SAMPLER_MIP_FILTER_NEAREST = 1,
    MSL_SAMPLER_MIP_FILTER_LINEAR = 2,
    MSL_SAMPLER_MIP_FILTER_INT_MAX = 0x7fffffff
};

enum MSLSamplerAddress
{
    MSL_SAMPLER_ADDRESS_CLAMP_TO_ZERO = 0,
    MSL_SAMPLER_ADDRESS_CLAMP_TO_EDGE = 1,
    MSL_SAMPLER_ADDRESS_CLAMP_TO_BORDER = 2,
    MSL_SAMPLER_ADDRESS_REPEAT = 3,
    MSL_SAMPLER_ADDRESS_MIRRORED_REPEAT = 4,
    MSL_SAMPLER_ADDRESS_INT_MAX = 0x7fffffff
};

enum MSLSamplerCompareFunc
{
    MSL_SAMPLER_COMPARE_FUNC_NEVER = 0,
    MSL_SAMPLER_COMPARE_FUNC_LESS = 1,
    MSL_SAMPLER_COMPARE_FUNC_LESS_EQUAL = 2,
    MSL_SAMPLER_COMPARE_FUNC_GREATER = 3,
    MSL_SAMPLER_COMPARE_FUNC_GREATER_EQUAL = 4,
    MSL_SAMPLER_COMPARE_FUNC_EQUAL = 5,
    MSL_SAMPLER_COMPARE_FUNC_NOT_EQUAL = 6,
    MSL_SAMPLER_COMPARE_FUNC_ALWAYS = 7,
    MSL_SAMPLER_COMPARE_FUNC_INT_MAX = 0x7fffffff
};

enum MSLSamplerBorderColor
{
    MSL_SAMPLER_BORDER_COLOR_TRANSPARENT_BLACK = 0,
    MSL_SAMPLER_BORDER_COLOR_OPAQUE_BLACK = 1,
    MSL_SAMPLER_BORDER_COLOR_OPAQUE_WHITE = 2,
    MSL_SAMPLER_BORDER_COLOR_INT_MAX = 0x7fffffff
};

enum MSLFormatResolution
{
    MSL_FORMAT_RESOLUTION_444 = 0,
    MSL_FORMAT_RESOLUTION_422,
    MSL_FORMAT_RESOLUTION_420,
    MSL_FORMAT_RESOLUTION_INT_MAX = 0x7fffffff
};

enum MSLChromaLocation
{
    MSL_CHROMA_LOCATION_COSITED_EVEN = 0,
    MSL_CHROMA_LOCATION_MIDPOINT,
    MSL_CHROMA_LOCATION_INT_MAX = 0x7fffffff
};

enum MSLComponentSwizzle
{
    MSL_COMPONENT_SWIZZLE_IDENTITY = 0,
    MSL_COMPONENT_SWIZZLE_ZERO,
    MSL_COMPONENT_SWIZZLE_ONE,
    MSL_COMPONENT_SWIZZLE_R,
    MSL_COMPONENT_SWIZZLE_G,
    MSL_COMPONENT_SWIZZLE_B,
    MSL_COMPONENT_SWIZZLE_A,
    MSL_COMPONENT_SWIZZLE_INT_MAX = 0x7fffffff
};

enum MSLSamplerYCbCrModelConversion
{
    MSL_SAMPLER_YCBCR_MODEL_CONVERSION_RGB_IDENTITY = 0,
    MSL_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_IDENTITY,
    MSL_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_BT_709,
    MSL_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_BT_601,
    MSL_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_BT_2020,
    MSL_SAMPLER_YCBCR_MODEL_CONVERSION_INT_MAX = 0x7fffffff
};

enum MSLSamplerYCbCrRange
{
    MSL_SAMPLER_YCBCR_RANGE_ITU_FULL = 0,
    MSL_SAMPLER_YCBCR_RANGE_ITU_NARROW,
    MSL_SAMPLER_YCBCR_RANGE_INT_MAX = 0x7fffffff
};

struct MSLConstexprSampler
{
    MSLSamplerCoord coord = MSL_SAMPLER_COORD_NORMALIZED;
    MSLSamplerFilter min_filter = MSL_SAMPLER_FILTER_NEAREST;
    MSLSamplerFilter mag_filter = MSL_SAMPLER_FILTER_NEAREST;
    MSLSamplerMipFilter mip_filter = MSL_SAMPLER_MIP_FILTER_NONE;
    MSLSamplerAddress s_address = MSL_SAMPLER_ADDRESS_CLAMP_TO_EDGE;
    MSLSamplerAddress t_address = MSL_SAMPLER_ADDRESS_CLAMP_TO_EDGE;
    MSLSamplerAddress r_address = MSL_SAMPLER_ADDRESS_CLAMP_TO_EDGE;
    MSLSamplerCompareFunc compare_func = MSL_SAMPLER_COMPARE_FUNC_NEVER;
    MSLSamplerBorderColor border_color = MSL_SAMPLER_BORDER_COLOR_TRANSPARENT_BLACK;
    float lod_clamp_min = 0.0f;
    float lod_clamp_max = 1000.0f;
    int max_anisotropy = 1;

    // Sampler Y'CbCr conversion parameters
    uint32_t planes = 0;
    MSLFormatResolution resolution = MSL_FORMAT_RESOLUTION_444;
    MSLSamplerFilter chroma_filter = MSL_SAMPLER_FILTER_NEAREST;
    MSLChromaLocation x_chroma_offset = MSL_CHROMA_LOCATION_COSITED_EVEN;
    MSLChromaLocation y_chroma_offset = MSL_CHROMA_LOCATION_COSITED_EVEN;
    MSLComponentSwizzle swizzle[4]; // IDENTITY, IDENTITY, IDENTITY, IDENTITY
    MSLSamplerYCbCrModelConversion ycbcr_model = MSL_SAMPLER_YCBCR_MODEL_CONVERSION_RGB_IDENTITY;
    MSLSamplerYCbCrRange ycbcr_range = MSL_SAMPLER_YCBCR_RANGE_ITU_FULL;
    uint32_t bpc = 8;

    bool compare_enable = false;
    bool lod_clamp_enable = false;
    bool anisotropy_enable = false;
    bool ycbcr_conversion_enable = false;

    MSLConstexprSampler()
    {
        for (uint32_t i = 0; i < 4; i++)
            swizzle[i] = MSL_COMPONENT_SWIZZLE_IDENTITY;
    }
    bool swizzle_is_identity() const
    {
        return (swizzle[0] == MSL_COMPONENT_SWIZZLE_IDENTITY && swizzle[1] == MSL_COMPONENT_SWIZZLE_IDENTITY &&
                swizzle[2] == MSL_COMPONENT_SWIZZLE_IDENTITY && swizzle[3] == MSL_COMPONENT_SWIZZLE_IDENTITY);
    }
    bool swizzle_has_one_or_zero() const
    {
        return (swizzle[0] == MSL_COMPONENT_SWIZZLE_ZERO || swizzle[0] == MSL_COMPONENT_SWIZZLE_ONE ||
                swizzle[1] == MSL_COMPONENT_SWIZZLE_ZERO || swizzle[1] == MSL_COMPONENT_SWIZZLE_ONE ||
                swizzle[2] == MSL_COMPONENT_SWIZZLE_ZERO || swizzle[2] == MSL_COMPONENT_SWIZZLE_ONE ||
                swizzle[3] == MSL_COMPONENT_SWIZZLE_ZERO || swizzle[3] == MSL_COMPONENT_SWIZZLE_ONE);
    }
};

// Special constant used in a MSLResourceBinding desc_set
// element to indicate the bindings for the push constants.
// Kinda deprecated. Just use ResourceBindingPushConstant{DescriptorSet,Binding} directly.
static const uint32_t kPushConstDescSet = ResourceBindingPushConstantDescriptorSet;

// Special constant used in a MSLResourceBinding binding
// element to indicate the bindings for the push constants.
// Kinda deprecated. Just use ResourceBindingPushConstant{DescriptorSet,Binding} directly.
static const uint32_t kPushConstBinding = ResourceBindingPushConstantBinding;

// Special constant used in a MSLResourceBinding binding
// element to indicate the buffer binding for swizzle buffers.
static const uint32_t kSwizzleBufferBinding = ~(1u);

// Special constant used in a MSLResourceBinding binding
// element to indicate the buffer binding for buffer size buffers to support OpArrayLength.
static const uint32_t kBufferSizeBufferBinding = ~(2u);

// Special constant used in a MSLResourceBinding binding
// element to indicate the buffer binding used for the argument buffer itself.
// This buffer binding should be kept as small as possible as all automatic bindings for buffers
// will start at max(kArgumentBufferBinding) + 1.
static const uint32_t kArgumentBufferBinding = ~(3u);

static const uint32_t kMaxArgumentBuffers = 8;

// The arbitrary maximum for the nesting of array of array copies.
static const uint32_t kArrayCopyMultidimMax = 6;

// Decompiles SPIR-V to Metal Shading Language
class CompilerMSL : public CompilerGLSL
{
public:
    // Options for compiling to Metal Shading Language
    struct Options
    {
        typedef enum
        {
            iOS = 0,
            macOS = 1
        } Platform;

        Platform platform = macOS;
        uint32_t msl_version = make_msl_version(1, 2);
        uint32_t texel_buffer_texture_width = 4096; // Width of 2D Metal textures used as 1D texel buffers
        uint32_t r32ui_linear_texture_alignment = 4;
        uint32_t r32ui_alignment_constant_id = 65535;
        uint32_t swizzle_buffer_index = 30;
        uint32_t indirect_params_buffer_index = 29;
        uint32_t shader_output_buffer_index = 28;
        uint32_t shader_patch_output_buffer_index = 27;
        uint32_t shader_tess_factor_buffer_index = 26;
        uint32_t buffer_size_buffer_index = 25;
        uint32_t view_mask_buffer_index = 24;
        uint32_t dynamic_offsets_buffer_index = 23;
        uint32_t shader_input_buffer_index = 22;
        uint32_t shader_index_buffer_index = 21;
        uint32_t shader_patch_input_buffer_index = 20;
        uint32_t shader_input_wg_index = 0;
        uint32_t device_index = 0;
        uint32_t enable_frag_output_mask = 0xffffffff;
        // Metal doesn't allow setting a fixed sample mask directly in the pipeline.
        // We can evade this restriction by ANDing the internal sample_mask output
        // of the shader with the additional fixed sample mask.
        uint32_t additional_fixed_sample_mask = 0xffffffff;
        bool enable_point_size_builtin = true;
        bool enable_frag_depth_builtin = true;
        bool enable_frag_stencil_ref_builtin = true;
        bool disable_rasterization = false;
        bool capture_output_to_buffer = false;
        bool swizzle_texture_samples = false;
        bool tess_domain_origin_lower_left = false;
        bool multiview = false;
        bool multiview_layered_rendering = true;
        bool view_index_from_device_index = false;
        bool dispatch_base = false;
        bool texture_1D_as_2D = false;

        // Enable use of Metal argument buffers.
        // MSL 2.0 must also be enabled.
        bool argument_buffers = false;

        // Defines Metal argument buffer tier levels.
        // Uses same values as Metal MTLArgumentBuffersTier enumeration.
        enum class ArgumentBuffersTier
        {
            Tier1 = 0,
            Tier2 = 1,
        };

        // When using Metal argument buffers, indicates the Metal argument buffer tier level supported by the Metal platform.
        // Ignored when Options::argument_buffers is disabled.
        // - Tier1 supports writable images on macOS, but not on iOS.
        // - Tier2 supports writable images on macOS and iOS, and higher resource count limits.
        // Tier capabilities based on recommendations from Apple engineering.
        ArgumentBuffersTier argument_buffers_tier = ArgumentBuffersTier::Tier1;

        // Enables specifick argument buffer format with extra information to track SSBO-length
        bool runtime_array_rich_descriptor = false;

        // Ensures vertex and instance indices start at zero. This reflects the behavior of HLSL with SV_VertexID and SV_InstanceID.
        bool enable_base_index_zero = false;

        // Fragment output in MSL must have at least as many components as the render pass.
        // Add support to explicit pad out components.
        bool pad_fragment_output_components = false;

        // Specifies whether the iOS target version supports the [[base_vertex]] and [[base_instance]] attributes.
        bool ios_support_base_vertex_instance = false;

        // Use Metal's native frame-buffer fetch API for subpass inputs.
        bool use_framebuffer_fetch_subpasses = false;

        // Enables use of "fma" intrinsic for invariant float math
        bool invariant_float_math = false;

        // Emulate texturecube_array with texture2d_array for iOS where this type is not available
        bool emulate_cube_array = false;

        // Allow user to enable decoration binding
        bool enable_decoration_binding = false;

        // Requires MSL 2.1, use the native support for texel buffers.
        bool texture_buffer_native = false;

        // Forces all resources which are part of an argument buffer to be considered active.
        // This ensures ABI compatibility between shaders where some resources might be unused,
        // and would otherwise declare a different IAB.
        bool force_active_argument_buffer_resources = false;

        // Aligns each resource in an argument buffer to its assigned index value, id(N),
        // by adding synthetic padding members in the argument buffer struct for any resources
        // in the argument buffer that are not defined and used by the shader. This allows
        // the shader to index into the correct argument in a descriptor set argument buffer
        // that is shared across shaders, where not all resources in the argument buffer are
        // defined in each shader. For this to work, an MSLResourceBinding must be provided for
        // all descriptors in any descriptor set held in an argument buffer in the shader, and
        // that MSLResourceBinding must have the basetype and count members populated correctly.
        // The implementation here assumes any inline blocks in the argument buffer is provided
        // in a Metal buffer, and doesn't take into consideration inline blocks that are
        // optionally embedded directly into the argument buffer via add_inline_uniform_block().
        bool pad_argument_buffer_resources = false;

        // Forces the use of plain arrays, which works around certain driver bugs on certain versions
        // of Intel Macbooks. See https://github.com/KhronosGroup/SPIRV-Cross/issues/1210.
        // May reduce performance in scenarios where arrays are copied around as value-types.
        bool force_native_arrays = false;

        // If a shader writes clip distance, also emit user varyings which
        // can be read in subsequent stages.
        bool enable_clip_distance_user_varying = true;

        // In a tessellation control shader, assume that more than one patch can be processed in a
        // single workgroup. This requires changes to the way the InvocationId and PrimitiveId
        // builtins are processed, but should result in more efficient usage of the GPU.
        bool multi_patch_workgroup = false;

        // Use storage buffers instead of vertex-style attributes for tessellation evaluation
        // input. This may require conversion of inputs in the generated post-tessellation
        // vertex shader, but allows the use of nested arrays.
        bool raw_buffer_tese_input = false;

        // If set, a vertex shader will be compiled as part of a tessellation pipeline.
        // It will be translated as a compute kernel, so it can use the global invocation ID
        // to index the output buffer.
        bool vertex_for_tessellation = false;

        // Assume that SubpassData images have multiple layers. Layered input attachments
        // are addressed relative to the Layer output from the vertex pipeline. This option
        // has no effect with multiview, since all input attachments are assumed to be layered
        // and will be addressed using the current ViewIndex.
        bool arrayed_subpass_input = false;

        // Whether to use SIMD-group or quadgroup functions to implement group non-uniform
        // operations. Some GPUs on iOS do not support the SIMD-group functions, only the
        // quadgroup functions.
        bool ios_use_simdgroup_functions = false;

        // If set, the subgroup size will be assumed to be one, and subgroup-related
        // builtins and operations will be emitted accordingly. This mode is intended to
        // be used by MoltenVK on hardware/software configurations which do not provide
        // sufficient support for subgroups.
        bool emulate_subgroups = false;

        // If nonzero, a fixed subgroup size to assume. Metal, similarly to VK_EXT_subgroup_size_control,
        // allows the SIMD-group size (aka thread execution width) to vary depending on
        // register usage and requirements. In certain circumstances--for example, a pipeline
        // in MoltenVK without VK_PIPELINE_SHADER_STAGE_CREATE_ALLOW_VARYING_SUBGROUP_SIZE_BIT_EXT--
        // this is undesirable. This fixes the value of the SubgroupSize builtin, instead of
        // mapping it to the Metal builtin [[thread_execution_width]]. If the thread
        // execution width is reduced, the extra invocations will appear to be inactive.
        // If zero, the SubgroupSize will be allowed to vary, and the builtin will be mapped
        // to the Metal [[thread_execution_width]] builtin.
        uint32_t fixed_subgroup_size = 0;

        enum class IndexType
        {
            None = 0,
            UInt16 = 1,
            UInt32 = 2
        };

        // The type of index in the index buffer, if present. For a compute shader, Metal
        // requires specifying the indexing at pipeline creation, rather than at draw time
        // as with graphics pipelines. This means we must create three different pipelines,
        // for no indexing, 16-bit indices, and 32-bit indices. Each requires different
        // handling for the gl_VertexIndex builtin. We may as well, then, create three
        // different shaders for these three scenarios.
        IndexType vertex_index_type = IndexType::None;

        // If set, a dummy [[sample_id]] input is added to a fragment shader if none is present.
        // This will force the shader to run at sample rate, assuming Metal does not optimize
        // the extra threads away.
        bool force_sample_rate_shading = false;

        // If set, gl_HelperInvocation will be set manually whenever a fragment is discarded.
        // Some Metal devices have a bug where simd_is_helper_thread() does not return true
        // after a fragment has been discarded. This is a workaround that is only expected to be needed
        // until the bug is fixed in Metal; it is provided as an option to allow disabling it when that occurs.
        bool manual_helper_invocation_updates = true;

        // If set, extra checks will be emitted in fragment shaders to prevent writes
        // from discarded fragments. Some Metal devices have a bug where writes to storage resources
        // from discarded fragment threads continue to occur, despite the fragment being
        // discarded. This is a workaround that is only expected to be needed until the
        // bug is fixed in Metal; it is provided as an option so it can be enabled
        // only when the bug is present.
        bool check_discarded_frag_stores = false;

        // If set, Lod operands to OpImageSample*DrefExplicitLod for 1D and 2D array images
        // will be implemented using a gradient instead of passing the level operand directly.
        // Some Metal devices have a bug where the level() argument to depth2d_array<T>::sample_compare()
        // in a fragment shader is biased by some unknown amount, possibly dependent on the
        // partial derivatives of the texture coordinates. This is a workaround that is only
        // expected to be needed until the bug is fixed in Metal; it is provided as an option
        // so it can be enabled only when the bug is present.
        bool sample_dref_lod_array_as_grad = false;

        // MSL doesn't guarantee coherence between writes and subsequent reads of read_write textures.
        // This inserts fences before each read of a read_write texture to ensure coherency.
        // If you're sure you never rely on this, you can set this to false for a possible performance improvement.
        // Note: Only Apple's GPU compiler takes advantage of the lack of coherency, so make sure to test on Apple GPUs if you disable this.
        bool readwrite_texture_fences = true;

        // Metal 3.1 introduced a Metal regression bug which causes infinite recursion during
        // Metal's analysis of an entry point input structure that is itself recursive. Enabling
        // this option will replace the recursive input declaration with a alternate variable of
        // type void*, and then cast to the correct type at the top of the entry point function.
        // The bug has been reported to Apple, and will hopefully be fixed in future releases.
        bool replace_recursive_inputs = false;

        // If set, manual fixups of gradient vectors for cube texture lookups will be performed.
        // All released Apple Silicon GPUs to date behave incorrectly when sampling a cube texture
        // with explicit gradients. They will ignore one of the three partial derivatives based
        // on the selected major axis, and expect the remaining derivatives to be partially
        // transformed.
        bool agx_manual_cube_grad_fixup = false;

        bool is_ios() const
        {
            return platform == iOS;
        }

        bool is_macos() const
        {
            return platform == macOS;
        }

        bool use_quadgroup_operation() const
        {
            return is_ios() && !ios_use_simdgroup_functions;
        }

        void set_msl_version(uint32_t major, uint32_t minor = 0, uint32_t patch = 0)
        {
            msl_version = make_msl_version(major, minor, patch);
        }

        bool supports_msl_version(uint32_t major, uint32_t minor = 0, uint32_t patch = 0) const
        {
            return msl_version >= make_msl_version(major, minor, patch);
        }

        static uint32_t make_msl_version(uint32_t major, uint32_t minor = 0, uint32_t patch = 0)
        {
            return (major * 10000) + (minor * 100) + patch;
        }
    };

    const Options &get_msl_options() const
    {
        return msl_options;
    }

    void set_msl_options(const Options &opts)
    {
        msl_options = opts;
    }

    // Provide feedback to calling API to allow runtime to disable pipeline
    // rasterization if vertex shader requires rasterization to be disabled.
    bool get_is_rasterization_disabled() const
    {
        return is_rasterization_disabled && (get_entry_point().model == spv::ExecutionModelVertex ||
                                             get_entry_point().model == spv::ExecutionModelTessellationControl ||
                                             get_entry_point().model == spv::ExecutionModelTessellationEvaluation);
    }

    // Provide feedback to calling API to allow it to pass an auxiliary
    // swizzle buffer if the shader needs it.
    bool needs_swizzle_buffer() const
    {
        return used_swizzle_buffer;
    }

    // Provide feedback to calling API to allow it to pass a buffer
    // containing STORAGE_BUFFER buffer sizes to support OpArrayLength.
    bool needs_buffer_size_buffer() const
    {
        return !buffers_requiring_array_length.empty();
    }

    bool buffer_requires_array_length(VariableID id) const
    {
        return buffers_requiring_array_length.count(id) != 0;
    }

    // Provide feedback to calling API to allow it to pass a buffer
    // containing the view mask for the current multiview subpass.
    bool needs_view_mask_buffer() const
    {
        return msl_options.multiview && !msl_options.view_index_from_device_index;
    }

    // Provide feedback to calling API to allow it to pass a buffer
    // containing the dispatch base workgroup ID.
    bool needs_dispatch_base_buffer() const
    {
        return msl_options.dispatch_base && !msl_options.supports_msl_version(1, 2);
    }

    // Provide feedback to calling API to allow it to pass an output
    // buffer if the shader needs it.
    bool needs_output_buffer() const
    {
        return capture_output_to_buffer && stage_out_var_id != ID(0);
    }

    // Provide feedback to calling API to allow it to pass a patch output
    // buffer if the shader needs it.
    bool needs_patch_output_buffer() const
    {
        return capture_output_to_buffer && patch_stage_out_var_id != ID(0);
    }

    // Provide feedback to calling API to allow it to pass an input threadgroup
    // buffer if the shader needs it.
    bool needs_input_threadgroup_mem() const
    {
        return capture_output_to_buffer && stage_in_var_id != ID(0);
    }

    explicit CompilerMSL(std::vector<uint32_t> spirv);
    CompilerMSL(const uint32_t *ir, size_t word_count);
    explicit CompilerMSL(const ParsedIR &ir);
    explicit CompilerMSL(ParsedIR &&ir);

    // input is a shader interface variable description used to fix up shader input variables.
    // If shader inputs are provided, is_msl_shader_input_used() will return true after
    // calling ::compile() if the location were used by the MSL code.
    void add_msl_shader_input(const MSLShaderInterfaceVariable &input);

    // output is a shader interface variable description used to fix up shader output variables.
    // If shader outputs are provided, is_msl_shader_output_used() will return true after
    // calling ::compile() if the location were used by the MSL code.
    void add_msl_shader_output(const MSLShaderInterfaceVariable &output);

    // resource is a resource binding to indicate the MSL buffer,
    // texture or sampler index to use for a particular SPIR-V description set
    // and binding. If resource bindings are provided,
    // is_msl_resource_binding_used() will return true after calling ::compile() if
    // the set/binding combination was used by the MSL code.
    void add_msl_resource_binding(const MSLResourceBinding &resource);

    // desc_set and binding are the SPIR-V descriptor set and binding of a buffer resource
    // in this shader. index is the index within the dynamic offset buffer to use. This
    // function marks that resource as using a dynamic offset (VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC
    // or VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC). This function only has any effect if argument buffers
    // are enabled. If so, the buffer will have its address adjusted at the beginning of the shader with
    // an offset taken from the dynamic offset buffer.
    void add_dynamic_buffer(uint32_t desc_set, uint32_t binding, uint32_t index);

    // desc_set and binding are the SPIR-V descriptor set and binding of a buffer resource
    // in this shader. This function marks that resource as an inline uniform block
    // (VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT). This function only has any effect if argument buffers
    // are enabled. If so, the buffer block will be directly embedded into the argument
    // buffer, instead of being referenced indirectly via pointer.
    void add_inline_uniform_block(uint32_t desc_set, uint32_t binding);

    // When using MSL argument buffers, we can force "classic" MSL 1.0 binding schemes for certain descriptor sets.
    // This corresponds to VK_KHR_push_descriptor in Vulkan.
    void add_discrete_descriptor_set(uint32_t desc_set);

    // If an argument buffer is large enough, it may need to be in the device storage space rather than
    // constant. Opt-in to this behavior here on a per set basis.
    void set_argument_buffer_device_address_space(uint32_t desc_set, bool device_storage);

    // Query after compilation is done. This allows you to check if an input location was used by the shader.
    bool is_msl_shader_input_used(uint32_t location);

    // Query after compilation is done. This allows you to check if an output location were used by the shader.
    bool is_msl_shader_output_used(uint32_t location);

    // If not using add_msl_shader_input, it's possible
    // that certain builtin attributes need to be automatically assigned locations.
    // This is typical for tessellation builtin inputs such as tess levels, gl_Position, etc.
    // This returns k_unknown_location if the location was explicitly assigned with
    // add_msl_shader_input or the builtin is not used, otherwise returns N in [[attribute(N)]].
    uint32_t get_automatic_builtin_input_location(spv::BuiltIn builtin) const;

    // If not using add_msl_shader_output, it's possible
    // that certain builtin attributes need to be automatically assigned locations.
    // This is typical for tessellation builtin outputs such as tess levels, gl_Position, etc.
    // This returns k_unknown_location if the location were explicitly assigned with
    // add_msl_shader_output or the builtin were not used, otherwise returns N in [[attribute(N)]].
    uint32_t get_automatic_builtin_output_location(spv::BuiltIn builtin) const;

    // NOTE: Only resources which are remapped using add_msl_resource_binding will be reported here.
    // Constexpr samplers are always assumed to be emitted.
    // No specific MSLResourceBinding remapping is required for constexpr samplers as long as they are remapped
    // by remap_constexpr_sampler(_by_binding).
    bool is_msl_resource_binding_used(spv::ExecutionModel model, uint32_t set, uint32_t binding) const;

    // This must only be called after a successful call to CompilerMSL::compile().
    // For a variable resource ID obtained through reflection API, report the automatically assigned resource index.
    // If the descriptor set was part of an argument buffer, report the [[id(N)]],
    // or [[buffer/texture/sampler]] binding for other resources.
    // If the resource was a combined image sampler, report the image binding here,
    // use the _secondary version of this call to query the sampler half of the resource.
    // If no binding exists, uint32_t(-1) is returned.
    uint32_t get_automatic_msl_resource_binding(uint32_t id) const;

    // Same as get_automatic_msl_resource_binding, but should only be used for combined image samplers, in which case the
    // sampler's binding is returned instead. For any other resource type, -1 is returned.
    // Secondary bindings are also used for the auxillary image atomic buffer.
    uint32_t get_automatic_msl_resource_binding_secondary(uint32_t id) const;

    // Same as get_automatic_msl_resource_binding, but should only be used for combined image samplers for multiplanar images,
    // in which case the second plane's binding is returned instead. For any other resource type, -1 is returned.
    uint32_t get_automatic_msl_resource_binding_tertiary(uint32_t id) const;

    // Same as get_automatic_msl_resource_binding, but should only be used for combined image samplers for triplanar images,
    // in which case the third plane's binding is returned instead. For any other resource type, -1 is returned.
    uint32_t get_automatic_msl_resource_binding_quaternary(uint32_t id) const;

    // Compiles the SPIR-V code into Metal Shading Language.
    std::string compile() override;

    // Remap a sampler with ID to a constexpr sampler.
    // Older iOS targets must use constexpr samplers in certain cases (PCF),
    // so a static sampler must be used.
    // The sampler will not consume a binding, but be declared in the entry point as a constexpr sampler.
    // This can be used on both combined image/samplers (sampler2D) or standalone samplers.
    // The remapped sampler must not be an array of samplers.
    // Prefer remap_constexpr_sampler_by_binding unless you're also doing reflection anyways.
    void remap_constexpr_sampler(VariableID id, const MSLConstexprSampler &sampler);

    // Same as remap_constexpr_sampler, except you provide set/binding, rather than variable ID.
    // Remaps based on ID take priority over set/binding remaps.
    void remap_constexpr_sampler_by_binding(uint32_t desc_set, uint32_t binding, const MSLConstexprSampler &sampler);

    // If using CompilerMSL::Options::pad_fragment_output_components, override the number of components we expect
    // to use for a particular location. The default is 4 if number of components is not overridden.
    void set_fragment_output_components(uint32_t location, uint32_t components);

    void set_combined_sampler_suffix(const char *suffix);
    const char *get_combined_sampler_suffix() const;

protected:
    // An enum of SPIR-V functions that are implemented in additional
    // source code that is added to the shader if necessary.
    enum SPVFuncImpl : uint8_t
    {
        SPVFuncImplNone,
        SPVFuncImplMod,
        SPVFuncImplRadians,
        SPVFuncImplDegrees,
        SPVFuncImplFindILsb,
        SPVFuncImplFindSMsb,
        SPVFuncImplFindUMsb,
        SPVFuncImplSSign,
        SPVFuncImplArrayCopyMultidimBase,
        // Unfortunately, we cannot use recursive templates in the MSL compiler properly,
        // so stamp out variants up to some arbitrary maximum.
        SPVFuncImplArrayCopy = SPVFuncImplArrayCopyMultidimBase + 1,
        SPVFuncImplArrayOfArrayCopy2Dim = SPVFuncImplArrayCopyMultidimBase + 2,
        SPVFuncImplArrayOfArrayCopy3Dim = SPVFuncImplArrayCopyMultidimBase + 3,
        SPVFuncImplArrayOfArrayCopy4Dim = SPVFuncImplArrayCopyMultidimBase + 4,
        SPVFuncImplArrayOfArrayCopy5Dim = SPVFuncImplArrayCopyMultidimBase + 5,
        SPVFuncImplArrayOfArrayCopy6Dim = SPVFuncImplArrayCopyMultidimBase + 6,
        SPVFuncImplTexelBufferCoords,
        SPVFuncImplImage2DAtomicCoords, // Emulate texture2D atomic operations
        SPVFuncImplGradientCube,
        SPVFuncImplFMul,
        SPVFuncImplFAdd,
        SPVFuncImplFSub,
        SPVFuncImplQuantizeToF16,
        SPVFuncImplCubemapTo2DArrayFace,
        SPVFuncImplUnsafeArray, // Allow Metal to use the array<T> template to make arrays a value type
        SPVFuncImplStorageMatrix, // Allow threadgroup construction of matrices
        SPVFuncImplInverse4x4,
        SPVFuncImplInverse3x3,
        SPVFuncImplInverse2x2,
        // It is very important that this come before *Swizzle and ChromaReconstruct*, to ensure it's
        // emitted before them.
        SPVFuncImplForwardArgs,
        // Likewise, this must come before *Swizzle.
        SPVFuncImplGetSwizzle,
        SPVFuncImplTextureSwizzle,
        SPVFuncImplGatherSwizzle,
        SPVFuncImplGatherCompareSwizzle,
        SPVFuncImplSubgroupBroadcast,
        SPVFuncImplSubgroupBroadcastFirst,
        SPVFuncImplSubgroupBallot,
        SPVFuncImplSubgroupBallotBitExtract,
        SPVFuncImplSubgroupBallotFindLSB,
        SPVFuncImplSubgroupBallotFindMSB,
        SPVFuncImplSubgroupBallotBitCount,
        SPVFuncImplSubgroupAllEqual,
        SPVFuncImplSubgroupShuffle,
        SPVFuncImplSubgroupShuffleXor,
        SPVFuncImplSubgroupShuffleUp,
        SPVFuncImplSubgroupShuffleDown,
        SPVFuncImplQuadBroadcast,
        SPVFuncImplQuadSwap,
        SPVFuncImplReflectScalar,
        SPVFuncImplRefractScalar,
        SPVFuncImplFaceForwardScalar,
        SPVFuncImplChromaReconstructNearest2Plane,
        SPVFuncImplChromaReconstructNearest3Plane,
        SPVFuncImplChromaReconstructLinear422CositedEven2Plane,
        SPVFuncImplChromaReconstructLinear422CositedEven3Plane,
        SPVFuncImplChromaReconstructLinear422Midpoint2Plane,
        SPVFuncImplChromaReconstructLinear422Midpoint3Plane,
        SPVFuncImplChromaReconstructLinear420XCositedEvenYCositedEven2Plane,
        SPVFuncImplChromaReconstructLinear420XCositedEvenYCositedEven3Plane,
        SPVFuncImplChromaReconstructLinear420XMidpointYCositedEven2Plane,
        SPVFuncImplChromaReconstructLinear420XMidpointYCositedEven3Plane,
        SPVFuncImplChromaReconstructLinear420XCositedEvenYMidpoint2Plane,
        SPVFuncImplChromaReconstructLinear420XCositedEvenYMidpoint3Plane,
        SPVFuncImplChromaReconstructLinear420XMidpointYMidpoint2Plane,
        SPVFuncImplChromaReconstructLinear420XMidpointYMidpoint3Plane,
        SPVFuncImplExpandITUFullRange,
        SPVFuncImplExpandITUNarrowRange,
        SPVFuncImplConvertYCbCrBT709,
        SPVFuncImplConvertYCbCrBT601,
        SPVFuncImplConvertYCbCrBT2020,
        SPVFuncImplDynamicImageSampler,
        SPVFuncImplRayQueryIntersectionParams,
        SPVFuncImplVariableDescriptor,
        SPVFuncImplVariableSizedDescriptor,
        SPVFuncImplVariableDescriptorArray,
        SPVFuncImplPaddedStd140
    };

    // If the underlying resource has been used for comparison then duplicate loads of that resource must be too
    // Use Metal's native frame-buffer fetch API for subpass inputs.
    void emit_texture_op(const Instruction &i, bool sparse) override;
    void emit_binary_ptr_op(uint32_t result_type, uint32_t result_id, uint32_t op0, uint32_t op1, const char *op);
    std::string to_ptr_expression(uint32_t id, bool register_expression_read = true);
    void emit_binary_unord_op(uint32_t result_type, uint32_t result_id, uint32_t op0, uint32_t op1, const char *op);
    void emit_instruction(const Instruction &instr) override;
    void emit_glsl_op(uint32_t result_type, uint32_t result_id, uint32_t op, const uint32_t *args,
                      uint32_t count) override;
    void emit_spv_amd_shader_trinary_minmax_op(uint32_t result_type, uint32_t result_id, uint32_t op,
                                               const uint32_t *args, uint32_t count) override;
    void emit_header() override;
    void emit_function_prototype(SPIRFunction &func, const Bitset &return_flags) override;
    void emit_sampled_image_op(uint32_t result_type, uint32_t result_id, uint32_t image_id, uint32_t samp_id) override;
    void emit_subgroup_op(const Instruction &i) override;
    std::string to_texture_op(const Instruction &i, bool sparse, bool *forward,
                              SmallVector<uint32_t> &inherited_expressions) override;
    void emit_fixup() override;
    std::string to_struct_member(const SPIRType &type, uint32_t member_type_id, uint32_t index,
                                 const std::string &qualifier = "");
    void emit_struct_member(const SPIRType &type, uint32_t member_type_id, uint32_t index,
                            const std::string &qualifier = "", uint32_t base_offset = 0) override;
    void emit_struct_padding_target(const SPIRType &type) override;
    std::string type_to_glsl(const SPIRType &type, uint32_t id, bool member);
    std::string type_to_glsl(const SPIRType &type, uint32_t id = 0) override;
    void emit_block_hints(const SPIRBlock &block) override;

    // Allow Metal to use the array<T> template to make arrays a value type
    std::string type_to_array_glsl(const SPIRType &type) override;
    std::string constant_op_expression(const SPIRConstantOp &cop) override;

    bool variable_decl_is_remapped_storage(const SPIRVariable &variable, spv::StorageClass storage) const override;

    // GCC workaround of lambdas calling protected functions (for older GCC versions)
    std::string variable_decl(const SPIRType &type, const std::string &name, uint32_t id = 0) override;

    std::string image_type_glsl(const SPIRType &type, uint32_t id = 0) override;
    std::string sampler_type(const SPIRType &type, uint32_t id);
    std::string builtin_to_glsl(spv::BuiltIn builtin, spv::StorageClass storage) override;
    std::string to_func_call_arg(const SPIRFunction::Parameter &arg, uint32_t id) override;
    std::string to_name(uint32_t id, bool allow_alias = true) const override;
    std::string to_function_name(const TextureFunctionNameArguments &args) override;
    std::string to_function_args(const TextureFunctionArguments &args, bool *p_forward) override;
    std::string to_initializer_expression(const SPIRVariable &var) override;
    std::string to_zero_initialized_expression(uint32_t type_id) override;

    std::string unpack_expression_type(std::string expr_str, const SPIRType &type, uint32_t physical_type_id,
                                       bool is_packed, bool row_major) override;

    // Returns true for BuiltInSampleMask because gl_SampleMask[] is an array in SPIR-V, but [[sample_mask]] is a scalar in Metal.
    bool builtin_translates_to_nonarray(spv::BuiltIn builtin) const override;

    std::string bitcast_glsl_op(const SPIRType &result_type, const SPIRType &argument_type) override;
    bool emit_complex_bitcast(uint32_t result_id, uint32_t id, uint32_t op0) override;
    bool skip_argument(uint32_t id) const override;
    std::string to_member_reference(uint32_t base, const SPIRType &type, uint32_t index, bool ptr_chain_is_resolved) override;
    std::string to_qualifiers_glsl(uint32_t id) override;
    void replace_illegal_names() override;
    void declare_constant_arrays();

    void replace_illegal_entry_point_names();
    void sync_entry_point_aliases_and_names();

    static const std::unordered_set<std::string> &get_reserved_keyword_set();
    static const std::unordered_set<std::string> &get_illegal_func_names();

    // Constant arrays of non-primitive types (i.e. matrices) won't link properly into Metal libraries
    void declare_complex_constant_arrays();

    bool is_patch_block(const SPIRType &type);
    bool is_non_native_row_major_matrix(uint32_t id) override;
    bool member_is_non_native_row_major_matrix(const SPIRType &type, uint32_t index) override;
    std::string convert_row_major_matrix(std::string exp_str, const SPIRType &exp_type, uint32_t physical_type_id,
                                         bool is_packed, bool relaxed) override;

    bool is_tesc_shader() const;
    bool is_tese_shader() const;

    void preprocess_op_codes();
    void localize_global_variables();
    void extract_global_variables_from_functions();
    void mark_packable_structs();
    void mark_as_packable(SPIRType &type);
    void mark_as_workgroup_struct(SPIRType &type);

    std::unordered_map<uint32_t, std::set<uint32_t>> function_global_vars;
    void extract_global_variables_from_function(uint32_t func_id, std::set<uint32_t> &added_arg_ids,
                                                std::unordered_set<uint32_t> &global_var_ids,
                                                std::unordered_set<uint32_t> &processed_func_ids);
    uint32_t add_interface_block(spv::StorageClass storage, bool patch = false);
    uint32_t add_interface_block_pointer(uint32_t ib_var_id, spv::StorageClass storage);

    struct InterfaceBlockMeta
    {
        struct LocationMeta
        {
            uint32_t base_type_id = 0;
            uint32_t num_components = 0;
            bool flat = false;
            bool noperspective = false;
            bool centroid = false;
            bool sample = false;
        };
        std::unordered_map<uint32_t, LocationMeta> location_meta;
        bool strip_array = false;
        bool allow_local_declaration = false;
    };

    std::string to_tesc_invocation_id();
    void emit_local_masked_variable(const SPIRVariable &masked_var, bool strip_array);
    void add_variable_to_interface_block(spv::StorageClass storage, const std::string &ib_var_ref, SPIRType &ib_type,
                                         SPIRVariable &var, InterfaceBlockMeta &meta);
    void add_composite_variable_to_interface_block(spv::StorageClass storage, const std::string &ib_var_ref,
                                                   SPIRType &ib_type, SPIRVariable &var, InterfaceBlockMeta &meta);
    void add_plain_variable_to_interface_block(spv::StorageClass storage, const std::string &ib_var_ref,
                                               SPIRType &ib_type, SPIRVariable &var, InterfaceBlockMeta &meta);
    bool add_component_variable_to_interface_block(spv::StorageClass storage, const std::string &ib_var_ref,
                                                   SPIRVariable &var, const SPIRType &type,
                                                   InterfaceBlockMeta &meta);
    void add_plain_member_variable_to_interface_block(spv::StorageClass storage,
                                                      const std::string &ib_var_ref, SPIRType &ib_type,
                                                      SPIRVariable &var, SPIRType &var_type,
                                                      uint32_t mbr_idx, InterfaceBlockMeta &meta,
                                                      const std::string &mbr_name_qual,
                                                      const std::string &var_chain_qual,
                                                      uint32_t &location, uint32_t &var_mbr_idx);
    void add_composite_member_variable_to_interface_block(spv::StorageClass storage,
                                                          const std::string &ib_var_ref, SPIRType &ib_type,
                                                          SPIRVariable &var, SPIRType &var_type,
                                                          uint32_t mbr_idx, InterfaceBlockMeta &meta,
                                                          const std::string &mbr_name_qual,
                                                          const std::string &var_chain_qual,
                                                          uint32_t &location, uint32_t &var_mbr_idx);
    void add_tess_level_input_to_interface_block(const std::string &ib_var_ref, SPIRType &ib_type, SPIRVariable &var);
    void add_tess_level_input(const std::string &base_ref, const std::string &mbr_name, SPIRVariable &var);

    void fix_up_interface_member_indices(spv::StorageClass storage, uint32_t ib_type_id);

    void mark_location_as_used_by_shader(uint32_t location, const SPIRType &type,
                                         spv::StorageClass storage, bool fallback = false);
    uint32_t ensure_correct_builtin_type(uint32_t type_id, spv::BuiltIn builtin);
    uint32_t ensure_correct_input_type(uint32_t type_id, uint32_t location, uint32_t component,
                                       uint32_t num_components, bool strip_array);

    void emit_custom_templates();
    void emit_custom_functions();
    void emit_resources();
    void emit_specialization_constants_and_structs();
    void emit_interface_block(uint32_t ib_var_id);
    bool maybe_emit_array_assignment(uint32_t id_lhs, uint32_t id_rhs);
    bool is_var_runtime_size_array(const SPIRVariable &var) const;
    uint32_t get_resource_array_size(const SPIRType &type, uint32_t id) const;

    void fix_up_shader_inputs_outputs();

    std::string func_type_decl(SPIRType &type);
    std::string entry_point_args_classic(bool append_comma);
    std::string entry_point_args_argument_buffer(bool append_comma);
    std::string entry_point_arg_stage_in();
    void entry_point_args_builtin(std::string &args);
    void entry_point_args_discrete_descriptors(std::string &args);
    std::string append_member_name(const std::string &qualifier, const SPIRType &type, uint32_t index);
    std::string ensure_valid_name(std::string name, std::string pfx);
    std::string to_sampler_expression(uint32_t id);
    std::string to_swizzle_expression(uint32_t id);
    std::string to_buffer_size_expression(uint32_t id);
    bool is_sample_rate() const;
    bool is_intersection_query() const;
    bool is_direct_input_builtin(spv::BuiltIn builtin);
    std::string builtin_qualifier(spv::BuiltIn builtin);
    std::string builtin_type_decl(spv::BuiltIn builtin, uint32_t id = 0);
    std::string built_in_func_arg(spv::BuiltIn builtin, bool prefix_comma);
    std::string member_attribute_qualifier(const SPIRType &type, uint32_t index);
    std::string member_location_attribute_qualifier(const SPIRType &type, uint32_t index);
    std::string argument_decl(const SPIRFunction::Parameter &arg);
    const char *descriptor_address_space(uint32_t id, spv::StorageClass storage, const char *plain_address_space) const;
    std::string round_fp_tex_coords(std::string tex_coords, bool coord_is_fp);
    uint32_t get_metal_resource_index(SPIRVariable &var, SPIRType::BaseType basetype, uint32_t plane = 0);
    uint32_t get_member_location(uint32_t type_id, uint32_t index, uint32_t *comp = nullptr) const;
    uint32_t get_or_allocate_builtin_input_member_location(spv::BuiltIn builtin,
                                                           uint32_t type_id, uint32_t index, uint32_t *comp = nullptr);
    uint32_t get_or_allocate_builtin_output_member_location(spv::BuiltIn builtin,
                                                            uint32_t type_id, uint32_t index, uint32_t *comp = nullptr);

    uint32_t get_physical_tess_level_array_size(spv::BuiltIn builtin) const;

    // MSL packing rules. These compute the effective packing rules as observed by the MSL compiler in the MSL output.
    // These values can change depending on various extended decorations which control packing rules.
    // We need to make these rules match up with SPIR-V declared rules.
    uint32_t get_declared_type_size_msl(const SPIRType &type, bool packed, bool row_major) const;
    uint32_t get_declared_type_array_stride_msl(const SPIRType &type, bool packed, bool row_major) const;
    uint32_t get_declared_type_matrix_stride_msl(const SPIRType &type, bool packed, bool row_major) const;
    uint32_t get_declared_type_alignment_msl(const SPIRType &type, bool packed, bool row_major) const;

    uint32_t get_declared_struct_member_size_msl(const SPIRType &struct_type, uint32_t index) const;
    uint32_t get_declared_struct_member_array_stride_msl(const SPIRType &struct_type, uint32_t index) const;
    uint32_t get_declared_struct_member_matrix_stride_msl(const SPIRType &struct_type, uint32_t index) const;
    uint32_t get_declared_struct_member_alignment_msl(const SPIRType &struct_type, uint32_t index) const;

    uint32_t get_declared_input_size_msl(const SPIRType &struct_type, uint32_t index) const;
    uint32_t get_declared_input_array_stride_msl(const SPIRType &struct_type, uint32_t index) const;
    uint32_t get_declared_input_matrix_stride_msl(const SPIRType &struct_type, uint32_t index) const;
    uint32_t get_declared_input_alignment_msl(const SPIRType &struct_type, uint32_t index) const;

    const SPIRType &get_physical_member_type(const SPIRType &struct_type, uint32_t index) const;
    SPIRType get_presumed_input_type(const SPIRType &struct_type, uint32_t index) const;

    uint32_t get_declared_struct_size_msl(const SPIRType &struct_type, bool ignore_alignment = false,
                                          bool ignore_padding = false) const;

    std::string to_component_argument(uint32_t id);
    void align_struct(SPIRType &ib_type, std::unordered_set<uint32_t> &aligned_structs);
    void mark_scalar_layout_structs(const SPIRType &ib_type);
    void mark_struct_members_packed(const SPIRType &type);
    void ensure_member_packing_rules_msl(SPIRType &ib_type, uint32_t index);
    bool validate_member_packing_rules_msl(const SPIRType &type, uint32_t index) const;
    std::string get_argument_address_space(const SPIRVariable &argument);
    std::string get_type_address_space(const SPIRType &type, uint32_t id, bool argument = false);
    const char *to_restrict(uint32_t id, bool space);
    SPIRType &get_stage_in_struct_type();
    SPIRType &get_stage_out_struct_type();
    SPIRType &get_patch_stage_in_struct_type();
    SPIRType &get_patch_stage_out_struct_type();
    std::string get_tess_factor_struct_name();
    SPIRType &get_uint_type();
    uint32_t get_uint_type_id();
    void emit_atomic_func_op(uint32_t result_type, uint32_t result_id, const char *op, spv::Op opcode,
                             uint32_t mem_order_1, uint32_t mem_order_2, bool has_mem_order_2, uint32_t op0, uint32_t op1 = 0,
                             bool op1_is_pointer = false, bool op1_is_literal = false, uint32_t op2 = 0);
    const char *get_memory_order(uint32_t spv_mem_sem);
    void add_pragma_line(const std::string &line);
    void add_typedef_line(const std::string &line);
    void emit_barrier(uint32_t id_exe_scope, uint32_t id_mem_scope, uint32_t id_mem_sem);
    bool emit_array_copy(const char *expr, uint32_t lhs_id, uint32_t rhs_id,
                         spv::StorageClass lhs_storage, spv::StorageClass rhs_storage) override;
    void build_implicit_builtins();
    uint32_t build_constant_uint_array_pointer();
    void emit_entry_point_declarations() override;
    bool uses_explicit_early_fragment_test();

    uint32_t builtin_frag_coord_id = 0;
    uint32_t builtin_sample_id_id = 0;
    uint32_t builtin_sample_mask_id = 0;
    uint32_t builtin_helper_invocation_id = 0;
    uint32_t builtin_vertex_idx_id = 0;
    uint32_t builtin_base_vertex_id = 0;
    uint32_t builtin_instance_idx_id = 0;
    uint32_t builtin_base_instance_id = 0;
    uint32_t builtin_view_idx_id = 0;
    uint32_t builtin_layer_id = 0;
    uint32_t builtin_invocation_id_id = 0;
    uint32_t builtin_primitive_id_id = 0;
    uint32_t builtin_subgroup_invocation_id_id = 0;
    uint32_t builtin_subgroup_size_id = 0;
    uint32_t builtin_dispatch_base_id = 0;
    uint32_t builtin_stage_input_size_id = 0;
    uint32_t builtin_local_invocation_index_id = 0;
    uint32_t builtin_workgroup_size_id = 0;
    uint32_t swizzle_buffer_id = 0;
    uint32_t buffer_size_buffer_id = 0;
    uint32_t view_mask_buffer_id = 0;
    uint32_t dynamic_offsets_buffer_id = 0;
    uint32_t uint_type_id = 0;
    uint32_t argument_buffer_padding_buffer_type_id = 0;
    uint32_t argument_buffer_padding_image_type_id = 0;
    uint32_t argument_buffer_padding_sampler_type_id = 0;

    bool does_shader_write_sample_mask = false;
    bool frag_shader_needs_discard_checks = false;

    void cast_to_variable_store(uint32_t target_id, std::string &expr, const SPIRType &expr_type) override;
    void cast_from_variable_load(uint32_t source_id, std::string &expr, const SPIRType &expr_type) override;
    void emit_store_statement(uint32_t lhs_expression, uint32_t rhs_expression) override;

    void analyze_sampled_image_usage();

    bool access_chain_needs_stage_io_builtin_translation(uint32_t base) override;
    bool prepare_access_chain_for_scalar_access(std::string &expr, const SPIRType &type, spv::StorageClass storage,
                                                bool &is_packed) override;
    void fix_up_interpolant_access_chain(const uint32_t *ops, uint32_t length);
    void check_physical_type_cast(std::string &expr, const SPIRType *type, uint32_t physical_type) override;

    bool emit_tessellation_access_chain(const uint32_t *ops, uint32_t length);
    bool emit_tessellation_io_load(uint32_t result_type, uint32_t id, uint32_t ptr);
    bool is_out_of_bounds_tessellation_level(uint32_t id_lhs);

    void ensure_builtin(spv::StorageClass storage, spv::BuiltIn builtin);

    void mark_implicit_builtin(spv::StorageClass storage, spv::BuiltIn builtin, uint32_t id);

    std::string convert_to_f32(const std::string &expr, uint32_t components);

    Options msl_options;
    std::set<SPVFuncImpl> spv_function_implementations;
    // Must be ordered to ensure declarations are in a specific order.
    std::map<LocationComponentPair, MSLShaderInterfaceVariable> inputs_by_location;
    std::unordered_map<uint32_t, MSLShaderInterfaceVariable> inputs_by_builtin;
    std::map<LocationComponentPair, MSLShaderInterfaceVariable> outputs_by_location;
    std::unordered_map<uint32_t, MSLShaderInterfaceVariable> outputs_by_builtin;
    std::unordered_set<uint32_t> location_inputs_in_use;
    std::unordered_set<uint32_t> location_inputs_in_use_fallback;
    std::unordered_set<uint32_t> location_outputs_in_use;
    std::unordered_set<uint32_t> location_outputs_in_use_fallback;
    std::unordered_map<uint32_t, uint32_t> fragment_output_components;
    std::unordered_map<uint32_t, uint32_t> builtin_to_automatic_input_location;
    std::unordered_map<uint32_t, uint32_t> builtin_to_automatic_output_location;
    std::set<std::string> pragma_lines;
    std::set<std::string> typedef_lines;
    SmallVector<uint32_t> vars_needing_early_declaration;

    std::unordered_map<StageSetBinding, std::pair<MSLResourceBinding, bool>, InternalHasher> resource_bindings;
    std::unordered_map<StageSetBinding, uint32_t, InternalHasher> resource_arg_buff_idx_to_binding_number;

    uint32_t next_metal_resource_index_buffer = 0;
    uint32_t next_metal_resource_index_texture = 0;
    uint32_t next_metal_resource_index_sampler = 0;
    // Intentionally uninitialized, works around MSVC 2013 bug.
    uint32_t next_metal_resource_ids[kMaxArgumentBuffers];

    VariableID stage_in_var_id = 0;
    VariableID stage_out_var_id = 0;
    VariableID patch_stage_in_var_id = 0;
    VariableID patch_stage_out_var_id = 0;
    VariableID stage_in_ptr_var_id = 0;
    VariableID stage_out_ptr_var_id = 0;
    VariableID tess_level_inner_var_id = 0;
    VariableID tess_level_outer_var_id = 0;
    VariableID stage_out_masked_builtin_type_id = 0;

    // Handle HLSL-style 0-based vertex/instance index.
    enum class TriState
    {
        Neutral,
        No,
        Yes
    };
    TriState needs_base_vertex_arg = TriState::Neutral;
    TriState needs_base_instance_arg = TriState::Neutral;

    bool has_sampled_images = false;
    bool builtin_declaration = false; // Handle HLSL-style 0-based vertex/instance index.

    bool is_using_builtin_array = false; // Force the use of C style array declaration.
    bool using_builtin_array() const;

    bool is_rasterization_disabled = false;
    bool capture_output_to_buffer = false;
    bool needs_swizzle_buffer_def = false;
    bool used_swizzle_buffer = false;
    bool added_builtin_tess_level = false;
    bool needs_subgroup_invocation_id = false;
    bool needs_subgroup_size = false;
    bool needs_sample_id = false;
    bool needs_helper_invocation = false;
    std::string qual_pos_var_name;
    std::string stage_in_var_name = "in";
    std::string stage_out_var_name = "out";
    std::string patch_stage_in_var_name = "patchIn";
    std::string patch_stage_out_var_name = "patchOut";
    std::string sampler_name_suffix = "Smplr";
    std::string swizzle_name_suffix = "Swzl";
    std::string buffer_size_name_suffix = "BufferSize";
    std::string plane_name_suffix = "Plane";
    std::string input_wg_var_name = "gl_in";
    std::string input_buffer_var_name = "spvIn";
    std::string output_buffer_var_name = "spvOut";
    std::string patch_input_buffer_var_name = "spvPatchIn";
    std::string patch_output_buffer_var_name = "spvPatchOut";
    std::string tess_factor_buffer_var_name = "spvTessLevel";
    std::string index_buffer_var_name = "spvIndices";
    spv::Op previous_instruction_opcode = spv::OpNop;

    // Must be ordered since declaration is in a specific order.
    std::map<uint32_t, MSLConstexprSampler> constexpr_samplers_by_id;
    std::unordered_map<SetBindingPair, MSLConstexprSampler, InternalHasher> constexpr_samplers_by_binding;
    const MSLConstexprSampler *find_constexpr_sampler(uint32_t id) const;

    std::unordered_set<uint32_t> buffers_requiring_array_length;
    SmallVector<std::pair<uint32_t, uint32_t>> buffer_aliases_argument;
    SmallVector<uint32_t> buffer_aliases_discrete;
    std::unordered_set<uint32_t> atomic_image_vars_emulated; // Emulate texture2D atomic operations
    std::unordered_set<uint32_t> pull_model_inputs;
    std::unordered_set<uint32_t> recursive_inputs;

    SmallVector<SPIRVariable *> entry_point_bindings;

    // Must be ordered since array is in a specific order.
    std::map<SetBindingPair, std::pair<uint32_t, uint32_t>> buffers_requiring_dynamic_offset;

    SmallVector<uint32_t> disabled_frag_outputs;

    std::unordered_set<SetBindingPair, InternalHasher> inline_uniform_blocks;

    uint32_t argument_buffer_ids[kMaxArgumentBuffers];
    uint32_t argument_buffer_discrete_mask = 0;
    uint32_t argument_buffer_device_storage_mask = 0;

    void analyze_argument_buffers();
    bool descriptor_set_is_argument_buffer(uint32_t desc_set) const;
    MSLResourceBinding &get_argument_buffer_resource(uint32_t desc_set, uint32_t arg_idx);
    void add_argument_buffer_padding_buffer_type(SPIRType &struct_type, uint32_t &mbr_idx, uint32_t &arg_buff_index, MSLResourceBinding &rez_bind);
    void add_argument_buffer_padding_image_type(SPIRType &struct_type, uint32_t &mbr_idx, uint32_t &arg_buff_index, MSLResourceBinding &rez_bind);
    void add_argument_buffer_padding_sampler_type(SPIRType &struct_type, uint32_t &mbr_idx, uint32_t &arg_buff_index, MSLResourceBinding &rez_bind);
    void add_argument_buffer_padding_type(uint32_t mbr_type_id, SPIRType &struct_type, uint32_t &mbr_idx, uint32_t &arg_buff_index, uint32_t count);

    uint32_t get_target_components_for_fragment_location(uint32_t location) const;
    uint32_t build_extended_vector_type(uint32_t type_id, uint32_t components,
                                        SPIRType::BaseType basetype = SPIRType::Unknown);
    uint32_t build_msl_interpolant_type(uint32_t type_id, bool is_noperspective);

    bool suppress_missing_prototypes = false;

    void add_spv_func_and_recompile(SPVFuncImpl spv_func);

    void activate_argument_buffer_resources();

    bool type_is_msl_framebuffer_fetch(const SPIRType &type) const;
    bool type_is_pointer(const SPIRType &type) const;
    bool type_is_pointer_to_pointer(const SPIRType &type) const;
    bool is_supported_argument_buffer_type(const SPIRType &type) const;

    bool variable_storage_requires_stage_io(spv::StorageClass storage) const;

    bool needs_manual_helper_invocation_updates() const
    {
        return msl_options.manual_helper_invocation_updates && msl_options.supports_msl_version(2, 3);
    }
    bool needs_frag_discard_checks() const
    {
        return get_execution_model() == spv::ExecutionModelFragment && msl_options.supports_msl_version(2, 3) &&
               msl_options.check_discarded_frag_stores && frag_shader_needs_discard_checks;
    }

    bool has_additional_fixed_sample_mask() const { return msl_options.additional_fixed_sample_mask != 0xffffffff; }
    std::string additional_fixed_sample_mask_str() const;

    // OpcodeHandler that handles several MSL preprocessing operations.
    struct OpCodePreprocessor : OpcodeHandler
    {
        OpCodePreprocessor(CompilerMSL &compiler_)
            : compiler(compiler_)
        {
        }

        bool handle(spv::Op opcode, const uint32_t *args, uint32_t length) override;
        CompilerMSL::SPVFuncImpl get_spv_func_impl(spv::Op opcode, const uint32_t *args);
        void check_resource_write(uint32_t var_id);

        CompilerMSL &compiler;
        std::unordered_map<uint32_t, uint32_t> result_types;
        std::unordered_map<uint32_t, uint32_t> image_pointers_emulated; // Emulate texture2D atomic operations
        bool suppress_missing_prototypes = false;
        bool uses_atomics = false;
        bool uses_image_write = false;
        bool uses_buffer_write = false;
        bool uses_discard = false;
        bool needs_subgroup_invocation_id = false;
        bool needs_subgroup_size = false;
        bool needs_sample_id = false;
        bool needs_helper_invocation = false;
    };

    // OpcodeHandler that scans for uses of sampled images
    struct SampledImageScanner : OpcodeHandler
    {
        SampledImageScanner(CompilerMSL &compiler_)
            : compiler(compiler_)
        {
        }

        bool handle(spv::Op opcode, const uint32_t *args, uint32_t) override;

        CompilerMSL &compiler;
    };

    // Sorts the members of a SPIRType and associated Meta info based on a settable sorting
    // aspect, which defines which aspect of the struct members will be used to sort them.
    // Regardless of the sorting aspect, built-in members always appear at the end of the struct.
    struct MemberSorter
    {
        enum SortAspect
        {
            LocationThenBuiltInType,
            Offset
        };

        void sort();
        bool operator()(uint32_t mbr_idx1, uint32_t mbr_idx2);
        MemberSorter(SPIRType &t, Meta &m, SortAspect sa);

        SPIRType &type;
        Meta &meta;
        SortAspect sort_aspect;
    };
};
} // namespace SPIRV_CROSS_NAMESPACE

#endif