src/tint/lang/spirv/writer/raise/shader_io.cc - tint - Git at Google

 // Copyright 2023 The Tint Authors.
 //
 // 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.

 #include "src/tint/lang/spirv/writer/raise/shader_io.h"

 #include <memory>
 #include <utility>

 #include "src/tint/lang/core/ir/builder.h"
 #include "src/tint/lang/core/ir/module.h"
 #include "src/tint/lang/core/ir/transform/shader_io.h"
 #include "src/tint/lang/core/ir/validator.h"
 #include "src/tint/lang/core/type/array.h"

 using namespace tint::core::fluent_types;     // NOLINT
 using namespace tint::core::number_suffixes;  // NOLINT

 namespace tint::spirv::writer::raise {

 namespace {

 /// PIMPL state for the parts of the shader IO transform specific to SPIR-V.
 /// For SPIR-V, we declare a global variable for each input and output. The wrapper entry point then
 /// loads from and stores to these variables. We also modify the type of the SampleMask builtin to
 /// be an array, as required by Vulkan.
 struct StateImpl : core::ir::transform::ShaderIOBackendState {
     /// The input variables.
     Vector<core::ir::Var*, 4> input_vars;
     /// The output variables.
     Vector<core::ir::Var*, 4> output_vars;

     /// The configuration options.
     const ShaderIOConfig& config;

     /// The frag_depth clamp arguments.
     core::ir::Value* frag_depth_clamp_args = nullptr;

     /// Constructor
     StateImpl(core::ir::Module& mod, core::ir::Function* f, const ShaderIOConfig& cfg)
         : ShaderIOBackendState(mod, f), config(cfg) {}

     /// Destructor
     ~StateImpl() override {}

     /// Declare a global variable for each IO entry listed in @p entries.
     /// @param vars the list of variables
     /// @param entries the entries to emit
     /// @param addrspace the address to use for the global variables
     /// @param access the access mode to use for the global variables
     /// @param name_suffix the suffix to add to struct and variable names
     void MakeVars(Vector<core::ir::Var*, 4>& vars,
                   Vector<core::type::Manager::StructMemberDesc, 4>& entries,
                   core::AddressSpace addrspace,
                   core::Access access,
                   const char* name_suffix) {
         for (auto io : entries) {
             StringStream name;
             name << ir.NameOf(func).Name();

             if (io.attributes.builtin) {
                 // SampleMask must be an array for Vulkan.
                 if (io.attributes.builtin.value() == core::BuiltinValue::kSampleMask) {
                     io.type = ty.array<u32, 1>();
                 }
                 name << "_" << io.attributes.builtin.value();

                 // Vulkan requires that fragment integer builtin inputs be Flat decorated.
                 if (func->Stage() == core::ir::Function::PipelineStage::kFragment &&
                     addrspace == core::AddressSpace::kIn &&
                     io.type->is_integer_scalar_or_vector()) {
                     io.attributes.interpolation = {core::InterpolationType::kFlat};
                 }
             } else {
                 name << "_loc" << io.attributes.location.value();
                 if (io.attributes.index.has_value()) {
                     name << "_idx" << io.attributes.index.value();
                 }
             }
             name << name_suffix;

             // Create an IO variable and add it to the root block.
             auto* ptr = ty.ptr(addrspace, io.type, access);
             auto* var = b.Var(name.str(), ptr);
             var->SetAttributes(core::ir::IOAttributes{
                 io.attributes.location,
                 io.attributes.index,
                 io.attributes.builtin,
                 io.attributes.interpolation,
                 io.attributes.invariant,
             });
             ir.root_block->Append(var);
             vars.Push(var);
         }
     }

     /// @copydoc ShaderIO::BackendState::FinalizeInputs
     Vector<core::ir::FunctionParam*, 4> FinalizeInputs() override {
         MakeVars(input_vars, inputs, core::AddressSpace::kIn, core::Access::kRead, "_Input");
         return tint::Empty;
     }

     /// @copydoc ShaderIO::BackendState::FinalizeOutputs
     core::ir::Value* FinalizeOutputs() override {
         MakeVars(output_vars, outputs, core::AddressSpace::kOut, core::Access::kWrite, "_Output");
         return nullptr;
     }

     /// @copydoc ShaderIO::BackendState::GetInput
     core::ir::Value* GetInput(core::ir::Builder& builder, uint32_t idx) override {
         // Load the input from the global variable declared earlier.
         auto* ptr = ty.ptr(core::AddressSpace::kIn, inputs[idx].type, core::Access::kRead);
         auto* from = input_vars[idx]->Result();
         if (inputs[idx].attributes.builtin) {
             if (inputs[idx].attributes.builtin.value() == core::BuiltinValue::kSampleMask) {
                 // SampleMask becomes an array for SPIR-V, so load from the first element.
                 from = builder.Access(ptr, input_vars[idx], 0_u)->Result();
             }
         }
         return builder.Load(from)->Result();
     }

     /// @copydoc ShaderIO::BackendState::SetOutput
     void SetOutput(core::ir::Builder& builder, uint32_t idx, core::ir::Value* value) override {
         // Store the output to the global variable declared earlier.
         auto* ptr = ty.ptr(core::AddressSpace::kOut, outputs[idx].type, core::Access::kWrite);
         auto* to = output_vars[idx]->Result();
         if (outputs[idx].attributes.builtin) {
             if (outputs[idx].attributes.builtin.value() == core::BuiltinValue::kSampleMask) {
                 // SampleMask becomes an array for SPIR-V, so store to the first element.
                 to = builder.Access(ptr, to, 0_u)->Result();
             }

             // Clamp frag_depth values if necessary.
             if (outputs[idx].attributes.builtin.value() == core::BuiltinValue::kFragDepth) {
                 value = ClampFragDepth(builder, value);
             }
         }
         builder.Store(to, value);
     }

     /// Clamp a frag_depth builtin value if necessary.
     /// @param builder the builder to use for new instructions
     /// @param frag_depth the incoming frag_depth value
     /// @returns the clamped value
     core::ir::Value* ClampFragDepth(core::ir::Builder& builder, core::ir::Value* frag_depth) {
         if (!config.clamp_frag_depth) {
             return frag_depth;
         }

         // Create the clamp args struct and variable.
         if (!frag_depth_clamp_args) {
             // Check that there are no push constants in the module already.
             for (auto* inst : *ir.root_block) {
                 if (auto* var = inst->As<core::ir::Var>()) {
                     auto* ptr = var->Result()->Type()->As<core::type::Pointer>();
                     if (ptr->AddressSpace() == core::AddressSpace::kPushConstant) {
                         TINT_ICE() << "cannot clamp frag_depth with pre-existing push constants";
                     }
                 }
             }

             // Declare the struct.
             auto* str = ty.Struct(ir.symbols.Register("FragDepthClampArgs"),
                                   {
                                       {ir.symbols.Register("min"), ty.f32()},
                                       {ir.symbols.Register("max"), ty.f32()},
                                   });
             str->SetStructFlag(core::type::kBlock);

             // Declare the variable.
             auto* var = b.Var("tint_frag_depth_clamp_args", ty.ptr(push_constant, str));
             ir.root_block->Append(var);
             frag_depth_clamp_args = var->Result();
         }

         // Clamp the value.
         auto* args = builder.Load(frag_depth_clamp_args);
         auto* frag_depth_min = builder.Access(ty.f32(), args, 0_u);
         auto* frag_depth_max = builder.Access(ty.f32(), args, 1_u);
         return builder
             .Call(ty.f32(), core::BuiltinFn::kClamp, frag_depth, frag_depth_min, frag_depth_max)
             ->Result();
     }

     /// @copydoc ShaderIO::BackendState::NeedsVertexPointSize
     bool NeedsVertexPointSize() const override { return config.emit_vertex_point_size; }
 };
 }  // namespace

 Result<SuccessType> ShaderIO(core::ir::Module& ir, const ShaderIOConfig& config) {
     auto result = ValidateAndDumpIfNeeded(ir, "ShaderIO transform");
     if (!result) {
         return result;
     }

     core::ir::transform::RunShaderIOBase(ir, [&](core::ir::Module& mod, core::ir::Function* func) {
         return std::make_unique<StateImpl>(mod, func, config);
     });

     return Success;
 }

 }  // namespace tint::spirv::writer::raise
	// Copyright 2023 The Tint Authors.
	//
	// 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.

	#include "src/tint/lang/spirv/writer/raise/shader_io.h"

	#include <memory>
	#include <utility>

	#include "src/tint/lang/core/ir/builder.h"
	#include "src/tint/lang/core/ir/module.h"
	#include "src/tint/lang/core/ir/transform/shader_io.h"
	#include "src/tint/lang/core/ir/validator.h"
	#include "src/tint/lang/core/type/array.h"

	using namespace tint::core::fluent_types; // NOLINT
	using namespace tint::core::number_suffixes; // NOLINT

	namespace tint::spirv::writer::raise {

	namespace {

	/// PIMPL state for the parts of the shader IO transform specific to SPIR-V.
	/// For SPIR-V, we declare a global variable for each input and output. The wrapper entry point then
	/// loads from and stores to these variables. We also modify the type of the SampleMask builtin to
	/// be an array, as required by Vulkan.
	struct StateImpl : core::ir::transform::ShaderIOBackendState {
	/// The input variables.
	Vector<core::ir::Var*, 4> input_vars;
	/// The output variables.
	Vector<core::ir::Var*, 4> output_vars;

	/// The configuration options.
	const ShaderIOConfig& config;

	/// The frag_depth clamp arguments.
	core::ir::Value* frag_depth_clamp_args = nullptr;

	/// Constructor
	StateImpl(core::ir::Module& mod, core::ir::Function* f, const ShaderIOConfig& cfg)
	: ShaderIOBackendState(mod, f), config(cfg) {}

	/// Destructor
	~StateImpl() override {}

	/// Declare a global variable for each IO entry listed in @p entries.
	/// @param vars the list of variables
	/// @param entries the entries to emit
	/// @param addrspace the address to use for the global variables
	/// @param access the access mode to use for the global variables
	/// @param name_suffix the suffix to add to struct and variable names
	void MakeVars(Vector<core::ir::Var*, 4>& vars,
	Vector<core::type::Manager::StructMemberDesc, 4>& entries,
	core::AddressSpace addrspace,
	core::Access access,
	const char* name_suffix) {
	for (auto io : entries) {
	StringStream name;
	name << ir.NameOf(func).Name();

	if (io.attributes.builtin) {
	// SampleMask must be an array for Vulkan.
	if (io.attributes.builtin.value() == core::BuiltinValue::kSampleMask) {
	io.type = ty.array<u32, 1>();
	}
	name << "_" << io.attributes.builtin.value();

	// Vulkan requires that fragment integer builtin inputs be Flat decorated.
	if (func->Stage() == core::ir::Function::PipelineStage::kFragment &&
	addrspace == core::AddressSpace::kIn &&
	io.type->is_integer_scalar_or_vector()) {
	io.attributes.interpolation = {core::InterpolationType::kFlat};
	}
	} else {
	name << "_loc" << io.attributes.location.value();
	if (io.attributes.index.has_value()) {
	name << "_idx" << io.attributes.index.value();
	}
	}
	name << name_suffix;

	// Create an IO variable and add it to the root block.
	auto* ptr = ty.ptr(addrspace, io.type, access);
	auto* var = b.Var(name.str(), ptr);
	var->SetAttributes(core::ir::IOAttributes{
	io.attributes.location,
	io.attributes.index,
	io.attributes.builtin,
	io.attributes.interpolation,
	io.attributes.invariant,
	});
	ir.root_block->Append(var);
	vars.Push(var);
	}
	}

	/// @copydoc ShaderIO::BackendState::FinalizeInputs
	Vector<core::ir::FunctionParam*, 4> FinalizeInputs() override {
	MakeVars(input_vars, inputs, core::AddressSpace::kIn, core::Access::kRead, "_Input");
	return tint::Empty;
	}

	/// @copydoc ShaderIO::BackendState::FinalizeOutputs
	core::ir::Value* FinalizeOutputs() override {
	MakeVars(output_vars, outputs, core::AddressSpace::kOut, core::Access::kWrite, "_Output");
	return nullptr;
	}

	/// @copydoc ShaderIO::BackendState::GetInput
	core::ir::Value* GetInput(core::ir::Builder& builder, uint32_t idx) override {
	// Load the input from the global variable declared earlier.
	auto* ptr = ty.ptr(core::AddressSpace::kIn, inputs[idx].type, core::Access::kRead);
	auto* from = input_vars[idx]->Result();
	if (inputs[idx].attributes.builtin) {
	if (inputs[idx].attributes.builtin.value() == core::BuiltinValue::kSampleMask) {
	// SampleMask becomes an array for SPIR-V, so load from the first element.
	from = builder.Access(ptr, input_vars[idx], 0_u)->Result();
	}
	}
	return builder.Load(from)->Result();
	}

	/// @copydoc ShaderIO::BackendState::SetOutput
	void SetOutput(core::ir::Builder& builder, uint32_t idx, core::ir::Value* value) override {
	// Store the output to the global variable declared earlier.
	auto* ptr = ty.ptr(core::AddressSpace::kOut, outputs[idx].type, core::Access::kWrite);
	auto* to = output_vars[idx]->Result();
	if (outputs[idx].attributes.builtin) {
	if (outputs[idx].attributes.builtin.value() == core::BuiltinValue::kSampleMask) {
	// SampleMask becomes an array for SPIR-V, so store to the first element.
	to = builder.Access(ptr, to, 0_u)->Result();
	}

	// Clamp frag_depth values if necessary.
	if (outputs[idx].attributes.builtin.value() == core::BuiltinValue::kFragDepth) {
	value = ClampFragDepth(builder, value);
	}
	}
	builder.Store(to, value);
	}

	/// Clamp a frag_depth builtin value if necessary.
	/// @param builder the builder to use for new instructions
	/// @param frag_depth the incoming frag_depth value
	/// @returns the clamped value
	core::ir::Value* ClampFragDepth(core::ir::Builder& builder, core::ir::Value* frag_depth) {
	if (!config.clamp_frag_depth) {
	return frag_depth;
	}

	// Create the clamp args struct and variable.
	if (!frag_depth_clamp_args) {
	// Check that there are no push constants in the module already.
	for (auto* inst : *ir.root_block) {
	if (auto* var = inst->As<core::ir::Var>()) {
	auto* ptr = var->Result()->Type()->As<core::type::Pointer>();
	if (ptr->AddressSpace() == core::AddressSpace::kPushConstant) {
	TINT_ICE() << "cannot clamp frag_depth with pre-existing push constants";
	}
	}
	}

	// Declare the struct.
	auto* str = ty.Struct(ir.symbols.Register("FragDepthClampArgs"),
	{
	{ir.symbols.Register("min"), ty.f32()},
	{ir.symbols.Register("max"), ty.f32()},
	});
	str->SetStructFlag(core::type::kBlock);

	// Declare the variable.
	auto* var = b.Var("tint_frag_depth_clamp_args", ty.ptr(push_constant, str));
	ir.root_block->Append(var);
	frag_depth_clamp_args = var->Result();
	}

	// Clamp the value.
	auto* args = builder.Load(frag_depth_clamp_args);
	auto* frag_depth_min = builder.Access(ty.f32(), args, 0_u);
	auto* frag_depth_max = builder.Access(ty.f32(), args, 1_u);
	return builder
	.Call(ty.f32(), core::BuiltinFn::kClamp, frag_depth, frag_depth_min, frag_depth_max)
	->Result();
	}

	/// @copydoc ShaderIO::BackendState::NeedsVertexPointSize
	bool NeedsVertexPointSize() const override { return config.emit_vertex_point_size; }
	};
	} // namespace

	Result<SuccessType> ShaderIO(core::ir::Module& ir, const ShaderIOConfig& config) {
	auto result = ValidateAndDumpIfNeeded(ir, "ShaderIO transform");
	if (!result) {
	return result;
	}

	core::ir::transform::RunShaderIOBase(ir, [&](core::ir::Module& mod, core::ir::Function* func) {
	return std::make_unique<StateImpl>(mod, func, config);
	});

	return Success;
	}

	} // namespace tint::spirv::writer::raise