src/tint/lang/hlsl/writer/function_test.cc

// Copyright 2024 The Dawn & Tint Authors
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this
//    list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice,
//    this list of conditions and the following disclaimer in the documentation
//    and/or other materials provided with the distribution.
//
// 3. Neither the name of the copyright holder nor the names of its
//    contributors may be used to endorse or promote products derived from
//    this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#include <utility>

#include "gtest/gtest.h"
#include "src/tint/lang/core/access.h"
#include "src/tint/lang/core/builtin_value.h"
#include "src/tint/lang/core/fluent_types.h"
#include "src/tint/lang/core/number.h"
#include "src/tint/lang/core/type/struct.h"
#include "src/tint/lang/hlsl/writer/helper_test.h"
#include "src/tint/utils/containers/vector.h"

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

namespace tint::hlsl::writer {
namespace {

TEST_F(HlslWriterTest, FunctionEmpty) {
    auto* func = b.Function("foo", ty.void_());
    func->Block()->Append(b.Return(func));

    ASSERT_TRUE(Generate()) << err_ << output_.hlsl;
    EXPECT_EQ(output_.hlsl, R"(
void foo() {
}

[numthreads(1, 1, 1)]
void unused_entry_point() {
}

)");
}

TEST_F(HlslWriterTest, FunctionWithParams) {
    auto* func = b.Function("my_func", ty.void_());
    func->SetParams({b.FunctionParam("a", ty.f32()), b.FunctionParam("b", ty.i32())});
    func->Block()->Append(b.Return(func));

    ASSERT_TRUE(Generate()) << err_ << output_.hlsl;
    EXPECT_EQ(output_.hlsl, R"(
void my_func(float a, int b) {
}

[numthreads(1, 1, 1)]
void unused_entry_point() {
}

)");
}

TEST_F(HlslWriterTest, FunctionEntryPoint) {
    auto* func = b.ComputeFunction("main");
    func->Block()->Append(b.Return(func));

    ASSERT_TRUE(Generate()) << err_ << output_.hlsl;
    EXPECT_EQ(output_.hlsl, R"(
[numthreads(1, 1, 1)]
void main() {
}

)");
}

TEST_F(HlslWriterTest, FunctionEntryPointWithParams) {
    core::IOAttributes pos_attrs{};
    pos_attrs.builtin = core::BuiltinValue::kPosition;

    Vector members{
        ty.Get<core::type::StructMember>(b.ir.symbols.New("pos"), ty.vec4<f32>(), 0u, 0u, 16u, 16u,
                                         pos_attrs),
    };
    auto* strct = ty.Struct(b.ir.symbols.New("Interface"), std::move(members));

    auto* func = b.Function("main", ty.void_(), core::ir::Function::PipelineStage::kFragment);
    auto* p = b.FunctionParam("p", strct);
    func->SetParams({p});

    func->Block()->Append(b.Return(func));

    ASSERT_TRUE(Generate()) << err_ << output_.hlsl;
    EXPECT_EQ(output_.hlsl, R"(struct Interface {
  float4 pos;
};

struct main_inputs {
  float4 Interface_pos : SV_Position;
};


void main_inner(Interface p) {
}

void main(main_inputs inputs) {
  Interface v = {float4(inputs.Interface_pos.xyz, (1.0f / inputs.Interface_pos.w))};
  main_inner(v);
}

)");
}

TEST_F(HlslWriterTest, FunctionPtrParameter) {
    // fn f(foo : ptr<function, f32>) -> f32 {
    //   return *foo;
    // }

    auto* foo = b.FunctionParam("foo", ty.ptr<function, f32>());
    auto* func = b.Function("f", ty.f32());
    func->SetParams({foo});
    b.Append(func->Block(), [&] { b.Return(func, b.Load(foo)); });

    ASSERT_TRUE(Generate()) << err_ << output_.hlsl;
    EXPECT_EQ(output_.hlsl, R"(
float f(inout float foo) {
  return foo;
}

[numthreads(1, 1, 1)]
void unused_entry_point() {
}

)");
}

TEST_F(HlslWriterTest, FunctionEntryPointWithInAndOutLocations) {
    // fn frag_main(@location(0) foo : f32) -> @location(1) f32 {
    //   return foo;
    // }

    auto* foo = b.FunctionParam("foo", ty.f32());
    foo->SetLocation(0);

    auto* func = b.Function("frag_main", ty.f32(), core::ir::Function::PipelineStage::kFragment);
    func->SetParams({foo});
    func->SetReturnLocation(1);
    func->Block()->Append(b.Return(func, foo));

    ASSERT_TRUE(Generate()) << err_ << output_.hlsl;
    EXPECT_EQ(output_.hlsl, R"(struct frag_main_outputs {
  float tint_symbol : SV_Target1;
};

struct frag_main_inputs {
  float foo : TEXCOORD0;
};


float frag_main_inner(float foo) {
  return foo;
}

frag_main_outputs frag_main(frag_main_inputs inputs) {
  frag_main_outputs v = {frag_main_inner(inputs.foo)};
  return v;
}

)");
}

TEST_F(HlslWriterTest, FunctionEntryPointWithInOutBuiltins) {
    // fn frag_main(@position(0) coord : vec4<f32>) -> @frag_depth f32 {
    //   return coord.x;
    // }

    auto* coord = b.FunctionParam("coord", ty.vec4<f32>());
    coord->SetBuiltin(core::BuiltinValue::kPosition);

    auto* func = b.Function("frag_main", ty.f32(), core::ir::Function::PipelineStage::kFragment);
    func->SetReturnBuiltin(core::BuiltinValue::kFragDepth);
    func->SetParams({coord});
    b.Append(func->Block(), [&] {
        auto* a = b.Swizzle(ty.f32(), coord, {0});
        b.Return(func, a);
    });

    ASSERT_TRUE(Generate()) << err_ << output_.hlsl;
    EXPECT_EQ(output_.hlsl, R"(struct frag_main_outputs {
  float tint_symbol : SV_Depth;
};

struct frag_main_inputs {
  float4 coord : SV_Position;
};


float frag_main_inner(float4 coord) {
  return coord.x;
}

frag_main_outputs frag_main(frag_main_inputs inputs) {
  frag_main_outputs v = {frag_main_inner(float4(inputs.coord.xyz, (1.0f / inputs.coord.w)))};
  return v;
}

)");
}

TEST_F(HlslWriterTest, FunctionEntryPointSharedStructDifferentStages) {
    // struct Interface {
    //   @builtin(position) pos : vec4<f32>;
    //   @location(1) col1 : f32;
    //   @location(2) col2 : f32;
    // };
    //
    // fn vert_main() -> Interface {
    //   return Interface(vec4<f32>(), 0.4, 0.6);
    // }
    //
    // fn frag_main(inputs : Interface) {
    //   const r = inputs.col1;
    //   const g = inputs.col2;
    //   const p = inputs.pos;
    // }

    core::IOAttributes pos_attrs{};
    pos_attrs.builtin = core::BuiltinValue::kPosition;
    core::IOAttributes col1_attrs{};
    col1_attrs.location = 1;
    core::IOAttributes col2_attrs{};
    col2_attrs.location = 2;

    Vector members{
        ty.Get<core::type::StructMember>(b.ir.symbols.New("pos"), ty.vec4<f32>(), 0u, 0u, 16u, 16u,
                                         pos_attrs),
        ty.Get<core::type::StructMember>(b.ir.symbols.New("col1"), ty.f32(), 1u, 16u, 4u, 4u,
                                         col1_attrs),
        ty.Get<core::type::StructMember>(b.ir.symbols.New("col2"), ty.f32(), 2u, 16u, 4u, 4u,
                                         col2_attrs),
    };
    auto* strct = ty.Struct(b.ir.symbols.New("Interface"), std::move(members));

    auto* vert_func = b.Function("vert_main", strct, core::ir::Function::PipelineStage::kVertex);
    b.Append(vert_func->Block(), [&] {  //
        b.Return(vert_func, b.Construct(strct, b.Zero(ty.vec4<f32>()), 0.5_f, 0.25_f));
    });

    auto* frag_param = b.FunctionParam("inputs", strct);
    auto* frag_func =
        b.Function("frag_main", ty.void_(), core::ir::Function::PipelineStage::kFragment);
    frag_func->SetParams({frag_param});
    b.Append(frag_func->Block(), [&] {
        auto* r = b.Access(ty.f32(), frag_param, 1_u);
        auto* g = b.Access(ty.f32(), frag_param, 2_u);
        auto* p = b.Access(ty.vec4<f32>(), frag_param, 0_u);

        b.Let("r", r);
        b.Let("g", g);
        b.Let("p", p);
        b.Return(frag_func);
    });

    ASSERT_TRUE(Generate()) << err_ << output_.hlsl;
    EXPECT_EQ(output_.hlsl, R"(struct Interface {
  float4 pos;
  float col1;
  float col2;
};

struct vert_main_outputs {
  float Interface_col1 : TEXCOORD1;
  float Interface_col2 : TEXCOORD2;
  float4 Interface_pos : SV_Position;
};

struct frag_main_inputs {
  float Interface_col1 : TEXCOORD1;
  float Interface_col2 : TEXCOORD2;
  float4 Interface_pos : SV_Position;
};


Interface vert_main_inner() {
  Interface v = {(0.0f).xxxx, 0.5f, 0.25f};
  return v;
}

void frag_main_inner(Interface inputs) {
  float r = inputs.col1;
  float g = inputs.col2;
  float4 p = inputs.pos;
}

vert_main_outputs vert_main() {
  Interface v_1 = vert_main_inner();
  vert_main_outputs v_2 = {v_1.col1, v_1.col2, v_1.pos};
  return v_2;
}

void frag_main(frag_main_inputs inputs) {
  Interface v_3 = {float4(inputs.Interface_pos.xyz, (1.0f / inputs.Interface_pos.w)), inputs.Interface_col1, inputs.Interface_col2};
  frag_main_inner(v_3);
}

)");
}

TEST_F(HlslWriterTest, FunctionEntryPointSharedStructHelperFunction) {
    // struct VertexOutput {
    //   @builtin(position) pos : vec4<f32>;
    // };
    // fn foo(x : f32) -> VertexOutput {
    //   return VertexOutput(vec4<f32>(x, x, x, 1.0));
    // }
    // fn vert_main1() -> VertexOutput {
    //   return foo(0.5);
    // }
    // fn vert_main2() -> VertexOutput {
    //   return foo(0.25);
    // }

    core::IOAttributes pos_attrs{};
    pos_attrs.builtin = core::BuiltinValue::kPosition;

    Vector members{ty.Get<core::type::StructMember>(b.ir.symbols.New("pos"), ty.vec4<f32>(), 0u, 0u,
                                                    16u, 16u, pos_attrs)};
    auto* strct = ty.Struct(b.ir.symbols.New("VertexOutput"), std::move(members));

    auto* x = b.FunctionParam("x", ty.f32());
    auto* foo_func = b.Function("foo", strct);
    foo_func->SetParams({x});
    b.Append(foo_func->Block(), [&] {  //
        b.Return(foo_func, b.Construct(strct, b.Construct(ty.vec4<f32>(), x, x, x, 1_f)));
    });

    {
        auto* vert1_func =
            b.Function("vert1_main1", strct, core::ir::Function::PipelineStage::kVertex);
        b.Append(vert1_func->Block(), [&] {  //
            b.Return(vert1_func, b.Call(foo_func, 0.5_f));
        });
    }

    {
        auto* vert2_func =
            b.Function("vert2_main1", strct, core::ir::Function::PipelineStage::kVertex);
        b.Append(vert2_func->Block(), [&] {  //
            b.Return(vert2_func, b.Call(foo_func, 0.25_f));
        });
    }

    ASSERT_TRUE(Generate()) << err_ << output_.hlsl;
    EXPECT_EQ(output_.hlsl, R"(struct VertexOutput {
  float4 pos;
};

struct vert1_main1_outputs {
  float4 VertexOutput_pos : SV_Position;
};

struct vert2_main1_outputs {
  float4 VertexOutput_pos : SV_Position;
};


VertexOutput foo(float x) {
  VertexOutput v = {float4(x, x, x, 1.0f)};
  return v;
}

VertexOutput vert1_main1_inner() {
  VertexOutput v_1 = foo(0.5f);
  return v_1;
}

VertexOutput vert2_main1_inner() {
  VertexOutput v_2 = foo(0.25f);
  return v_2;
}

vert1_main1_outputs vert1_main1() {
  VertexOutput v_3 = vert1_main1_inner();
  vert1_main1_outputs v_4 = {v_3.pos};
  return v_4;
}

vert2_main1_outputs vert2_main1() {
  VertexOutput v_5 = vert2_main1_inner();
  vert2_main1_outputs v_6 = {v_5.pos};
  return v_6;
}

)");
}

TEST_F(HlslWriterTest, FunctionEntryPointWithUniform) {
    // struct Uniforms {
    //   coord: vec4f,
    // }
    // @group(1) @binding(0) var<uniform> ubo : Uniforms;
    //
    // fn sub_func(param: f32) -> f32 {
    //   return ubo.coord.x;
    // }
    // @fragment fn frag_main() {
    //   var v = sub_func(1f);
    // }

    Vector inner_members{ty.Get<core::type::StructMember>(b.ir.symbols.New("coord"), ty.f32(), 0u,
                                                          0u, 4u, 4u, core::IOAttributes{})};
    auto* inner_strct = ty.Struct(b.ir.symbols.New("Inner"), std::move(inner_members));

    Vector members{ty.Get<core::type::StructMember>(b.ir.symbols.New("coord"), inner_strct, 0u, 0u,
                                                    16u, 16u, core::IOAttributes{})};
    auto* strct = ty.Struct(b.ir.symbols.New("Uniforms"), std::move(members));

    auto* ubo = b.Var("ubo", uniform, strct);
    ubo->SetBindingPoint(1, 0);
    b.ir.root_block->Append(ubo);

    auto* param = b.FunctionParam("param", ty.f32());
    auto* sub_func = b.Function("sub_func", ty.f32());
    sub_func->SetParams({param});

    b.Append(sub_func->Block(), [&] {  //
        auto* a = b.Access(ty.ptr<uniform, f32>(), ubo, 0_u, 0_u);
        b.Return(sub_func, b.Load(a));
    });

    auto* frag_func =
        b.Function("frag_main", ty.void_(), core::ir::Function::PipelineStage::kFragment);
    b.Append(frag_func->Block(), [&] {
        b.Var("v", b.Call(sub_func, 1_f));
        b.Return(frag_func);
    });

    ASSERT_TRUE(Generate()) << err_ << output_.hlsl;
    EXPECT_EQ(output_.hlsl, R"(
cbuffer cbuffer_ubo : register(b0, space1) {
  uint4 ubo[1];
};
float sub_func(float param) {
  return asfloat(ubo[0u].x);
}

void frag_main() {
  float v = sub_func(1.0f);
}

)");
}

TEST_F(HlslWriterTest, FunctionEntryPointWithUniformStruct) {
    // struct Uniforms {
    //   coord: vec4f,
    // }
    //
    // @group(1) @binding(0) var<uniform> ubo: Uniforms;
    //
    // @fragment fn frag_main() {
    //   var v = ubo.coord.x;
    // }

    Vector inner_members{ty.Get<core::type::StructMember>(b.ir.symbols.New("coord"), ty.f32(), 0u,
                                                          0u, 4u, 4u, core::IOAttributes{})};
    auto* inner_strct = ty.Struct(b.ir.symbols.New("Inner"), std::move(inner_members));

    Vector members{ty.Get<core::type::StructMember>(b.ir.symbols.New("coord"), inner_strct, 0u, 0u,
                                                    16u, 16u, core::IOAttributes{})};
    auto* strct = ty.Struct(b.ir.symbols.New("Uniforms"), std::move(members));

    auto* ubo = b.Var("ubo", uniform, strct);
    ubo->SetBindingPoint(1, 0);
    b.ir.root_block->Append(ubo);

    auto* func = b.Function("frag_main", ty.void_(), core::ir::Function::PipelineStage::kFragment);
    b.Append(func->Block(), [&] {  //
        auto* a = b.Access(ty.ptr<uniform, f32>(), ubo, 0_u, 0_u);
        b.Var("v", b.Load(a));
        b.Return(func);
    });

    ASSERT_TRUE(Generate()) << err_ << output_.hlsl;
    EXPECT_EQ(output_.hlsl, R"(
cbuffer cbuffer_ubo : register(b0, space1) {
  uint4 ubo[1];
};
void frag_main() {
  float v = asfloat(ubo[0u].x);
}

)");
}

TEST_F(HlslWriterTest, FunctionEntryPointWithRWStorageBufferRead) {
    // struct Data {
    //   a: i32,
    //   b: f32,
    // }
    // @group(1) @binding(0) var<storage, read_write> coord: Data;
    //
    // @fragment fn frag_main() {
    //   var v = coord.b;
    // }

    Vector members{ty.Get<core::type::StructMember>(b.ir.symbols.New("a"), ty.i32(), 0u, 0u, 4u, 4u,
                                                    core::IOAttributes{}),
                   ty.Get<core::type::StructMember>(b.ir.symbols.New("b"), ty.f32(), 1u, 4u, 4u, 4u,
                                                    core::IOAttributes{})};
    auto* strct = ty.Struct(b.ir.symbols.New("Data"), std::move(members));

    auto* coord = b.Var("coord", storage, strct, read_write);
    coord->SetBindingPoint(1, 0);
    b.ir.root_block->Append(coord);

    auto* func = b.Function("frag_main", ty.void_(), core::ir::Function::PipelineStage::kFragment);
    b.Append(func->Block(), [&] {  //
        auto* a = b.Access(ty.ptr(storage, ty.i32()), coord, 0_u);
        b.Var("v", b.Load(a));

        b.Return(func);
    });

    ASSERT_TRUE(Generate()) << err_ << output_.hlsl;
    EXPECT_EQ(output_.hlsl,
              R"(
RWByteAddressBuffer coord : register(u0, space1);
void frag_main() {
  int v = asint(coord.Load(0u));
}

)");
}

TEST_F(HlslWriterTest, FunctionEntryPointWithROStorageBufferRead) {
    // struct Data {
    //   a: i32,
    //   b: f32,
    // }
    // @group(1) @binding(0) var<storage, read> coord: Data;
    //
    // @fragment fn frag_main() {
    //   var v = coord.b;
    // }

    Vector members{ty.Get<core::type::StructMember>(b.ir.symbols.New("a"), ty.i32(), 0u, 0u, 4u, 4u,
                                                    core::IOAttributes{}),
                   ty.Get<core::type::StructMember>(b.ir.symbols.New("b"), ty.f32(), 1u, 4u, 4u, 4u,
                                                    core::IOAttributes{})};
    auto* strct = ty.Struct(b.ir.symbols.New("Data"), std::move(members));

    auto* coord = b.Var("coord", storage, strct, core::Access::kRead);
    coord->SetBindingPoint(1, 0);
    b.ir.root_block->Append(coord);

    auto* func = b.Function("frag_main", ty.void_(), core::ir::Function::PipelineStage::kFragment);
    b.Append(func->Block(), [&] {  //
        auto* a = b.Access(ty.ptr<storage, f32, core::Access::kRead>(), coord, 1_u);
        b.Var("v", b.Load(a));
        b.Return(func);
    });

    ASSERT_TRUE(Generate()) << err_ << output_.hlsl;
    EXPECT_EQ(output_.hlsl,
              R"(
ByteAddressBuffer coord : register(t0, space1);
void frag_main() {
  float v = asfloat(coord.Load(4u));
}

)");
}

TEST_F(HlslWriterTest, FunctionEntryPointWithWOStorageBufferStore) {
    // struct Data {
    //   a: i32,
    //   b: f32,
    // }
    // @group(1) @binding(0) var<storage, write> coord: Data;
    //
    // @fragment fn frag_main() {
    //   coord.b = 2f;
    // }

    Vector members{ty.Get<core::type::StructMember>(b.ir.symbols.New("a"), ty.i32(), 0u, 0u, 4u, 4u,
                                                    core::IOAttributes{}),
                   ty.Get<core::type::StructMember>(b.ir.symbols.New("b"), ty.f32(), 1u, 4u, 4u, 4u,
                                                    core::IOAttributes{})};
    auto* strct = ty.Struct(b.ir.symbols.New("Data"), std::move(members));

    auto* coord = b.Var("coord", storage, strct, core::Access::kReadWrite);
    coord->SetBindingPoint(1, 0);
    b.ir.root_block->Append(coord);

    auto* func = b.Function("frag_main", ty.void_(), core::ir::Function::PipelineStage::kFragment);
    b.Append(func->Block(), [&] {  //
        b.Store(b.Access(ty.ptr(storage, ty.f32()), coord, 1_u), 2_f);
        b.Return(func);
    });

    ASSERT_TRUE(Generate()) << err_ << output_.hlsl;
    EXPECT_EQ(output_.hlsl,
              R"(
RWByteAddressBuffer coord : register(u0, space1);
void frag_main() {
  coord.Store(4u, asuint(2.0f));
}

)");
}

TEST_F(HlslWriterTest, FunctionEntryPointWithStorageBufferStore) {
    // struct Data {
    //   a: i32,
    //   b: f32,
    // }
    // @group(1) @binding(0) var<storage, write> coord: Data;
    //
    // @fragment fn frag_main() {
    //   coord.b = 2f;
    // }

    Vector members{ty.Get<core::type::StructMember>(b.ir.symbols.New("a"), ty.i32(), 0u, 0u, 4u, 4u,
                                                    core::IOAttributes{}),
                   ty.Get<core::type::StructMember>(b.ir.symbols.New("b"), ty.f32(), 1u, 4u, 4u, 4u,
                                                    core::IOAttributes{})};
    auto* strct = ty.Struct(b.ir.symbols.New("Data"), std::move(members));

    auto* coord = b.Var("coord", storage, strct, read_write);
    coord->SetBindingPoint(1, 0);
    b.ir.root_block->Append(coord);

    auto* func = b.Function("frag_main", ty.void_(), core::ir::Function::PipelineStage::kFragment);
    b.Append(func->Block(), [&] {  //
        b.Store(b.Access(ty.ptr(storage, ty.f32()), coord, 1_u), 2_f);
        b.Return(func);
    });

    ASSERT_TRUE(Generate()) << err_ << output_.hlsl;
    EXPECT_EQ(output_.hlsl,
              R"(
RWByteAddressBuffer coord : register(u0, space1);
void frag_main() {
  coord.Store(4u, asuint(2.0f));
}

)");
}

TEST_F(HlslWriterTest, FunctionCalledByEntryPointWithUniform) {
    // Struct S {
    //   x: f32,
    // }
    // @group(1) @binding(0) var<uniform> coord: S;
    //
    // fn sub_func() -> f32 {
    //   return coord.x;
    // }
    // @fragment fn frag_main() {
    //   var v = sub_func(1f);
    // }

    Vector members{ty.Get<core::type::StructMember>(b.ir.symbols.New("x"), ty.f32(), 0u, 0u, 4u, 4u,
                                                    core::IOAttributes{})};
    auto* strct = ty.Struct(b.ir.symbols.New("S"), std::move(members));

    auto* coord = b.Var("coord", uniform, strct);
    coord->SetBindingPoint(1, 0);
    b.ir.root_block->Append(coord);

    auto* param = b.FunctionParam("param", ty.f32());
    auto* sub_func = b.Function("sub_func", ty.f32());
    sub_func->SetParams({param});

    b.Append(sub_func->Block(), [&] {
        auto* a = b.Access(ty.ptr<uniform, f32, core::Access::kRead>(), coord, 0_u);
        b.Return(sub_func, b.Load(a));
    });

    auto* func = b.Function("frag_main", ty.void_(), core::ir::Function::PipelineStage::kFragment);
    b.Append(func->Block(), [&] {  //
        b.Var("v", b.Call(sub_func, 1_f));
        b.Return(func);
    });

    ASSERT_TRUE(Generate()) << err_ << output_.hlsl;
    EXPECT_EQ(output_.hlsl, R"(
cbuffer cbuffer_coord : register(b0, space1) {
  uint4 coord[1];
};
float sub_func(float param) {
  return asfloat(coord[0u].x);
}

void frag_main() {
  float v = sub_func(1.0f);
}

)");
}

TEST_F(HlslWriterTest, FunctionCalledByEntryPointWithStorageBuffer) {
    // Struct S {
    //   x: f32,
    // }
    // @group(1) @binding(0) var<storage, read_write> coord: S;
    //
    // fn sub_func() -> f32 {
    //   return coord.x;
    // }
    // @fragment fn frag_main() {
    //   var v = sub_func();
    // }

    Vector members{ty.Get<core::type::StructMember>(b.ir.symbols.New("x"), ty.f32(), 0u, 0u, 4u, 4u,
                                                    core::IOAttributes{})};
    auto* strct = ty.Struct(b.ir.symbols.New("S"), std::move(members));

    auto* coord = b.Var("coord", storage, strct, core::Access::kReadWrite);
    coord->SetBindingPoint(1, 0);
    b.ir.root_block->Append(coord);

    auto* sub_func = b.Function("sub_func", ty.f32());
    b.Append(sub_func->Block(), [&] {
        auto* a = b.Access(ty.ptr<storage, f32>(), coord, 0_u);
        b.Return(sub_func, b.Load(a));
    });

    auto* func = b.Function("frag_main", ty.void_(), core::ir::Function::PipelineStage::kFragment);
    b.Append(func->Block(), [&] {  //
        b.Var("v", b.Call(sub_func));
        b.Return(func);
    });

    ASSERT_TRUE(Generate()) << err_ << output_.hlsl;
    EXPECT_EQ(output_.hlsl,
              R"(
RWByteAddressBuffer coord : register(u0, space1);
float sub_func() {
  return asfloat(coord.Load(0u));
}

void frag_main() {
  float v = sub_func();
}

)");
}

TEST_F(HlslWriterTest, FunctionEntryPointCompute) {
    // @compute @workgroup_size(1) fn main() {}

    auto* func = b.ComputeFunction("main");
    func->Block()->Append(b.Return(func));

    ASSERT_TRUE(Generate()) << err_ << output_.hlsl;
    EXPECT_EQ(output_.hlsl, R"(
[numthreads(1, 1, 1)]
void main() {
}

)");
}

TEST_F(HlslWriterTest, FunctionEntryPointComputeWithWorkgroupLiteral) {
    // @compute @workgroup_size(2, 4, 6) fn main() {}

    auto* func = b.ComputeFunction("main", 2_u, 4_u, 6_u);
    func->Block()->Append(b.Return(func));

    ASSERT_TRUE(Generate()) << err_ << output_.hlsl;
    EXPECT_EQ(output_.hlsl, R"(
[numthreads(2, 4, 6)]
void main() {
}

)");
}

TEST_F(HlslWriterTest, FunctionWithArrayParams) {
    // fn my_func(a: array<f32, 5>) {}

    auto* func = b.Function("my_func", ty.void_());
    auto* p = b.FunctionParam("a", ty.array<f32, 5>());
    func->SetParams({p});
    func->Block()->Append(b.Return(func));

    ASSERT_TRUE(Generate()) << err_ << output_.hlsl;
    EXPECT_EQ(output_.hlsl, R"(
void my_func(float a[5]) {
}

[numthreads(1, 1, 1)]
void unused_entry_point() {
}

)");
}

TEST_F(HlslWriterTest, FunctionWithArrayReturn) {
    // fn my_func() -> array<f32, 5> {
    //   return array<f32, 5>();
    // }

    auto* func = b.Function("my_func", ty.array<f32, 5>());
    func->Block()->Append(b.Return(func, b.Zero(ty.array<f32, 5>())));

    ASSERT_TRUE(Generate()) << err_ << output_.hlsl;
    EXPECT_EQ(output_.hlsl, R"(
typedef float ary_ret[5];
ary_ret my_func() {
  float v[5] = (float[5])0;
  return v;
}

[numthreads(1, 1, 1)]
void unused_entry_point() {
}

)");
}

TEST_F(HlslWriterTest, FunctionWithDiscardAndVoidReturnWithContinueExecution) {
    // fn my_func(a: i32) {
    //   if (a == 0) {
    //     discard;
    //   }
    // }

    auto* func = b.Function("my_func", ty.void_());
    auto* p = b.FunctionParam("a", ty.i32());
    func->SetParams({p});

    b.Append(func->Block(), [&] {
        auto* i = b.If(b.Equal(ty.bool_(), p, 0_i));
        b.Append(i->True(), [&] {
            b.Discard();
            b.ExitIf(i);
        });
        b.Return(func);
    });
    tint::hlsl::writer::Options options;
    // FXC must use demote to helper transform.
    options.compiler = tint::hlsl::writer::Options::Compiler::kFXC;
    ASSERT_TRUE(Generate(options)) << err_ << output_.hlsl;
    EXPECT_EQ(output_.hlsl, R"(
static bool continue_execution = true;
void my_func(int a) {
  if ((a == int(0))) {
    continue_execution = false;
  }
}

[numthreads(1, 1, 1)]
void unused_entry_point() {
}

)");
}

TEST_F(HlslWriterTest, FunctionWithDiscardAndVoidReturnWithPlatformDiscard) {
    // fn my_func(a: i32) {
    //   if (a == 0) {
    //     discard;
    //   }
    // }

    auto* func = b.Function("my_func", ty.void_());
    auto* p = b.FunctionParam("a", ty.i32());
    func->SetParams({p});

    b.Append(func->Block(), [&] {
        auto* i = b.If(b.Equal(ty.bool_(), p, 0_i));
        b.Append(i->True(), [&] {
            b.Discard();
            b.ExitIf(i);
        });
        b.Return(func);
    });
    tint::hlsl::writer::Options options;
    options.compiler = tint::hlsl::writer::Options::Compiler::kDXC;
    ASSERT_TRUE(Generate(options)) << err_ << output_.hlsl;
    EXPECT_EQ(output_.hlsl, R"(
void my_func(int a) {
  if ((a == int(0))) {
    discard;
  }
}

[numthreads(1, 1, 1)]
void unused_entry_point() {
}

)");
}

TEST_F(HlslWriterTest, FunctionWithDiscardAndNonVoidReturnWithContinueExecution) {
    // fn my_func(a: i32) -> i32 {
    //   if (a == 0) {
    //     discard;
    //   }
    //   return 42;
    // }

    auto* func = b.Function("my_func", ty.i32());
    auto* a = b.FunctionParam("a", ty.i32());
    func->SetParams({a});

    b.Append(func->Block(), [&] {
        auto* i = b.If(b.Equal(ty.bool_(), a, 0_i));
        b.Append(i->True(), [&] {
            b.Discard();
            b.ExitIf(i);
        });
        b.Return(func, 42_i);
    });

    tint::hlsl::writer::Options options;
    // FXC must use demote to helper transform.
    options.compiler = tint::hlsl::writer::Options::Compiler::kFXC;

    ASSERT_TRUE(Generate(options)) << err_ << output_.hlsl;
    EXPECT_EQ(output_.hlsl, R"(
static bool continue_execution = true;
int my_func(int a) {
  if ((a == int(0))) {
    continue_execution = false;
  }
  return int(42);
}

[numthreads(1, 1, 1)]
void unused_entry_point() {
}

)");
}

TEST_F(HlslWriterTest, FunctionWithDiscardAndNonVoidReturnWithPlatformDiscard) {
    // fn my_func(a: i32) -> i32 {
    //   if (a == 0) {
    //     discard;
    //   }
    //   return 42;
    // }

    auto* func = b.Function("my_func", ty.i32());
    auto* a = b.FunctionParam("a", ty.i32());
    func->SetParams({a});

    b.Append(func->Block(), [&] {
        auto* i = b.If(b.Equal(ty.bool_(), a, 0_i));
        b.Append(i->True(), [&] {
            b.Discard();
            b.ExitIf(i);
        });
        b.Return(func, 42_i);
    });

    tint::hlsl::writer::Options options;
    options.compiler = tint::hlsl::writer::Options::Compiler::kDXC;
    ASSERT_TRUE(Generate(options)) << err_ << output_.hlsl;
    EXPECT_EQ(output_.hlsl, R"(
int my_func(int a) {
  if ((a == int(0))) {
    discard;
  }
  return int(42);
}

[numthreads(1, 1, 1)]
void unused_entry_point() {
}

)");
}

// https://crbug.com/tint/297
TEST_F(HlslWriterTest, FunctionMultipleEntryPointWithSameModuleVar) {
    // struct Data {
    //   d : f32;
    // };
    // @binding(0) @group(0) var<storage, read_write> data : Data;
    //
    // @compute @workgroup_size(1)
    // fn a() {
    //   var v = data.d;
    //   return;
    // }
    //
    // @compute @workgroup_size(1)
    // fn b() {
    //   var v = data.d;
    //   return;
    // }

    Vector members{ty.Get<core::type::StructMember>(b.ir.symbols.New("d"), ty.f32(), 0u, 0u, 4u, 4u,
                                                    core::IOAttributes{})};
    auto* strct = ty.Struct(b.ir.symbols.New("Data"), std::move(members));

    auto* data = b.Var("data", storage, strct, read_write);
    data->SetBindingPoint(0, 0);
    b.ir.root_block->Append(data);

    {
        auto* func = b.ComputeFunction("a");
        b.Append(func->Block(), [&] {  //
            auto* a = b.Access(ty.ptr<storage, f32>(), data, 0_u);
            b.Var("v", b.Load(a));
            b.Return(func);
        });
    }

    {
        auto* func = b.ComputeFunction("b");
        b.Append(func->Block(), [&] {  //
            auto* a = b.Access(ty.ptr<storage, f32>(), data, 0_u);
            b.Var("v", b.Load(a));
            b.Return(func);
        });
    }

    ASSERT_TRUE(Generate()) << err_ << output_.hlsl;
    EXPECT_EQ(output_.hlsl, R"(
RWByteAddressBuffer data : register(u0);
[numthreads(1, 1, 1)]
void a() {
  float v = asfloat(data.Load(0u));
}

[numthreads(1, 1, 1)]
void b() {
  float v = asfloat(data.Load(0u));
}

)");
}

TEST_F(HlslWriterTest, DuplicateConstant) {
    auto* ret_arr = b.Function("ret_arr", ty.array<vec4<i32>, 4>());
    b.Append(ret_arr->Block(), [&] { b.Return(ret_arr, b.Zero<array<vec4<i32>, 4>>()); });

    auto* func = b.Function("foo", ty.void_(), core::ir::Function::PipelineStage::kFragment);
    b.Append(func->Block(), [&] {
        b.Let("src_let", b.Zero<array<vec4<i32>, 4>>());
        b.Return(func);
    });

    ASSERT_TRUE(Generate()) << err_ << output_.hlsl;
    EXPECT_EQ(output_.hlsl, R"(
typedef int4 ary_ret[4];
ary_ret ret_arr() {
  int4 v[4] = (int4[4])0;
  return v;
}

void foo() {
  int4 src_let[4] = (int4[4])0;
}

)");
}

}  // namespace
}  // namespace tint::hlsl::writer