glsl_decompiler: Implementation

2 files changed, 1481 insertions, 0 deletions

diff --git a/src/video_core/shader/glsl_decompiler.cpp b/src/video_core/shader/glsl_decompiler.cpp
new file mode 100644
index 000000000..46a48652d
--- /dev/null
+++ b/src/video_core/shader/glsl_decompiler.cpp
@@ -0,0 +1,1393 @@
+// Copyright 2018 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <string>
+#include <string_view>
+#include <variant>
+
+#include <fmt/format.h>
+
+#include "common/alignment.h"
+#include "common/assert.h"
+#include "common/common_types.h"
+#include "video_core/engines/maxwell_3d.h"
+#include "video_core/shader/glsl_decompiler.h"
+#include "video_core/shader/shader_ir.h"
+
+namespace OpenGL::GLShader {
+
+using Tegra::Shader::Attribute;
+using Tegra::Shader::Header;
+using Tegra::Shader::IpaInterpMode;
+using Tegra::Shader::IpaMode;
+using Tegra::Shader::IpaSampleMode;
+using namespace VideoCommon::Shader;
+
+using Maxwell = Tegra::Engines::Maxwell3D::Regs;
+using ShaderStage = Tegra::Engines::Maxwell3D::Regs::ShaderStage;
+using Operation = const OperationNode&;
+
+enum : u32 { POSITION_VARYING_LOCATION = 0, GENERIC_VARYING_START_LOCATION = 1 };
+constexpr u32 MAX_CONSTBUFFER_ELEMENTS = 65536 / 16; // TODO(Rodrigo): Use rasterizer's value
+
+enum class Type { Bool, Float, Int, Uint, HalfFloat };
+
+class ShaderWriter {
+public:
+    void AddExpression(std::string_view text) {
+        DEBUG_ASSERT(scope >= 0);
+        if (!text.empty()) {
+            AppendIndentation();
+        }
+        shader_source += text;
+    }
+
+    void AddLine(std::string_view text) {
+        AddExpression(text);
+        AddNewLine();
+    }
+
+    void AddLine(char character) {
+        DEBUG_ASSERT(scope >= 0);
+        AppendIndentation();
+        shader_source += character;
+        AddNewLine();
+    }
+
+    void AddNewLine() {
+        DEBUG_ASSERT(scope >= 0);
+        shader_source += '\n';
+    }
+
+    std::string GenerateTemporal() {
+        std::string temporal = "tmp";
+        temporal += std::to_string(temporal_index++);
+        return temporal;
+    }
+
+    std::string GetResult() {
+        return std::move(shader_source);
+    }
+
+    s32 scope = 0;
+
+private:
+    void AppendIndentation() {
+        shader_source.append(static_cast<std::size_t>(scope) * 4, ' ');
+    }
+
+    std::string shader_source;
+    u32 temporal_index = 1;
+};
+
+/// Generates code to use for a swizzle operation.
+static std::string GetSwizzle(u32 elem) {
+    ASSERT(elem <= 3);
+    std::string swizzle = ".";
+    swizzle += "xyzw"[elem];
+    return swizzle;
+}
+
+static bool IsPrecise(Operation operand) {
+    const auto& meta = operand.GetMeta();
+
+    if (std::holds_alternative<MetaArithmetic>(meta)) {
+        return std::get<MetaArithmetic>(meta).precise;
+    }
+    if (std::holds_alternative<MetaHalfArithmetic>(meta)) {
+        return std::get<MetaHalfArithmetic>(meta).precise;
+    }
+    return false;
+}
+
+static bool IsPrecise(Node node) {
+    if (!std::holds_alternative<OperationNode>(*node)) {
+        return false;
+    }
+    return IsPrecise(std::get<OperationNode>(*node));
+}
+
+class GLSLDecompiler final {
+public:
+    explicit GLSLDecompiler(const ShaderIR& ir, ShaderStage stage, std::string suffix)
+        : ir{ir}, stage{stage}, suffix{suffix}, header{ir.GetHeader()} {}
+
+    void Decompile() {
+        DeclareVertex();
+        DeclareRegisters();
+        DeclarePredicates();
+        DeclareLocalMemory();
+        DeclareInternalFlags();
+        DeclareInputAttributes();
+        DeclareOutputAttributes();
+        DeclareConstantBuffers();
+        DeclareSamplers();
+
+        code.AddLine("void execute_" + suffix + "() {");
+        ++code.scope;
+
+        // VM's program counter
+        const auto first_address = ir.GetBasicBlocks().begin()->first;
+        code.AddLine("uint jmp_to = " + std::to_string(first_address) + "u;");
+
+        // TODO(Subv): Figure out the actual depth of the flow stack, for now it seems
+        // unlikely that shaders will use 20 nested SSYs and PBKs.
+        constexpr u32 FLOW_STACK_SIZE = 20;
+        code.AddLine(fmt::format("uint flow_stack[{}];", FLOW_STACK_SIZE));
+        code.AddLine("uint flow_stack_top = 0u;");
+
+        code.AddLine("while (true) {");
+        ++code.scope;
+
+        code.AddLine("switch (jmp_to) {");
+
+        for (const auto& pair : ir.GetBasicBlocks()) {
+            const auto [address, bb] = pair;
+            code.AddLine(fmt::format("case 0x{:x}u: {{", address));
+            ++code.scope;
+
+            VisitBasicBlock(bb);
+
+            --code.scope;
+            code.AddLine('}');
+        }
+
+        code.AddLine("default: return;");
+        code.AddLine('}');
+
+        for (std::size_t i = 0; i < 2; ++i) {
+            --code.scope;
+            code.AddLine('}');
+        }
+    }
+
+    std::string GetResult() {
+        return code.GetResult();
+    }
+
+    ShaderEntries GetShaderEntries() const {
+        ShaderEntries entries;
+        for (const auto& cbuf : ir.GetConstantBuffers()) {
+            ConstBufferEntry desc(cbuf.second, stage, GetConstBufferBlock(cbuf.first), cbuf.first);
+            entries.const_buffers.push_back(desc);
+        }
+        for (const auto& sampler : ir.GetSamplers()) {
+            SamplerEntry desc(sampler, stage, GetSampler(sampler));
+            entries.samplers.push_back(desc);
+        }
+        entries.clip_distances = ir.GetClipDistances();
+        entries.shader_length = ir.GetLength();
+        return entries;
+    }
+
+private:
+    using OperationDecompilerFn = std::string (GLSLDecompiler::*)(Operation);
+    using OperationDecompilersArray =
+        std::array<OperationDecompilerFn, static_cast<std::size_t>(OperationCode::Amount)>;
+
+    void DeclareVertex() {
+        if (stage != ShaderStage::Vertex)
+            return;
+
+        bool clip_distances_declared = false;
+
+        code.AddLine("out gl_PerVertex {");
+        ++code.scope;
+
+        code.AddLine("vec4 gl_Position;");
+
+        for (const auto o : ir.GetOutputAttributes()) {
+            if (o == Attribute::Index::PointSize)
+                code.AddLine("float gl_PointSize;");
+            if (!clip_distances_declared && (o == Attribute::Index::ClipDistances0123 ||
+                                             o == Attribute::Index::ClipDistances4567)) {
+                code.AddLine("float gl_ClipDistance[];");
+                clip_distances_declared = true;
+            }
+        }
+
+        --code.scope;
+        code.AddLine("};");
+        code.AddNewLine();
+    }
+
+    void DeclareRegisters() {
+        const auto& registers = ir.GetRegisters();
+        for (const u32 gpr : registers) {
+            code.AddLine("float " + GetRegister(gpr) + " = 0;");
+        }
+        if (!registers.empty())
+            code.AddNewLine();
+    }
+
+    void DeclarePredicates() {
+        const auto& predicates = ir.GetPredicates();
+        for (const auto pred : predicates) {
+            code.AddLine("bool " + GetPredicate(pred) + " = false;");
+        }
+        if (!predicates.empty())
+            code.AddNewLine();
+    }
+
+    void DeclareLocalMemory() {
+        if (const u64 local_memory_size = header.GetLocalMemorySize(); local_memory_size > 0) {
+            const auto element_count = Common::AlignUp(local_memory_size, 4) / 4;
+            code.AddLine("float " + GetLocalMemory() + '[' + std::to_string(element_count) + "];");
+            code.AddNewLine();
+        }
+    }
+
+    void DeclareInternalFlags() {
+        for (u32 flag = 0; flag < static_cast<u32>(InternalFlag::Amount); flag++) {
+            const InternalFlag flag_code = static_cast<InternalFlag>(flag);
+            code.AddLine("bool " + GetInternalFlag(flag_code) + " = false;");
+        }
+        code.AddNewLine();
+    }
+
+    std::string GetInputFlags(const IpaMode& input_mode) {
+        const IpaSampleMode sample_mode = input_mode.sampling_mode;
+        const IpaInterpMode interp_mode = input_mode.interpolation_mode;
+        std::string out;
+
+        switch (interp_mode) {
+        case IpaInterpMode::Flat:
+            out += "flat ";
+            break;
+        case IpaInterpMode::Linear:
+            out += "noperspective ";
+            break;
+        case IpaInterpMode::Perspective:
+            // Default, Smooth
+            break;
+        default:
+            UNIMPLEMENTED_MSG("Unhandled IPA interp mode: {}", static_cast<u32>(interp_mode));
+        }
+        switch (sample_mode) {
+        case IpaSampleMode::Centroid:
+            // It can be implemented with the "centroid " keyword in GLSL
+            UNIMPLEMENTED_MSG("Unimplemented IPA sampler mode centroid");
+            break;
+        case IpaSampleMode::Default:
+            // Default, n/a
+            break;
+        default:
+            UNIMPLEMENTED_MSG("Unimplemented IPA sampler mode: {}", static_cast<u32>(sample_mode));
+        }
+        return out;
+    }
+
+    void DeclareInputAttributes() {
+        const auto& attributes = ir.GetInputAttributes();
+        for (const auto element : attributes) {
+            const Attribute::Index index = element.first;
+            const IpaMode& input_mode = *element.second.begin();
+            if (index < Attribute::Index::Attribute_0 || index > Attribute::Index::Attribute_31) {
+                // Skip when it's not a generic attribute
+                continue;
+            }
+
+            ASSERT(element.second.size() > 0);
+            // UNIMPLEMENTED_IF_MSG(element.second.size() > 1,
+            //                     "Multiple input flag modes are not supported in GLSL");
+
+            // TODO(bunnei): Use proper number of elements for these
+            u32 idx = static_cast<u32>(index) - static_cast<u32>(Attribute::Index::Attribute_0);
+            if (stage != ShaderStage::Vertex) {
+                // If inputs are varyings, add an offset
+                idx += GENERIC_VARYING_START_LOCATION;
+            }
+
+            std::string attr = GetInputAttribute(index);
+            if (stage == ShaderStage::Geometry) {
+                attr = "gs_" + attr + "[]";
+            }
+            code.AddLine("layout (location = " + std::to_string(idx) + ") " +
+                         GetInputFlags(input_mode) + "in vec4 " + attr + ';');
+        }
+        if (!attributes.empty())
+            code.AddNewLine();
+    }
+
+    void DeclareOutputAttributes() {
+        const auto& attributes = ir.GetOutputAttributes();
+        for (const auto index : attributes) {
+            if (index < Attribute::Index::Attribute_0 || index > Attribute::Index::Attribute_31) {
+                // Skip when it's not a generic attribute
+                continue;
+            }
+            // TODO(bunnei): Use proper number of elements for these
+            const auto idx = static_cast<u32>(index) -
+                             static_cast<u32>(Attribute::Index::Attribute_0) +
+                             GENERIC_VARYING_START_LOCATION;
+            code.AddLine("layout (location = " + std::to_string(idx) + ") out vec4 " +
+                         GetOutputAttribute(index) + ';');
+        }
+        if (!attributes.empty())
+            code.AddNewLine();
+    }
+
+    void DeclareConstantBuffers() {
+        for (const auto& entry : ir.GetConstantBuffers()) {
+            const auto [index, size] = entry;
+            code.AddLine("layout (std140) uniform " + GetConstBufferBlock(index) + " {");
+            code.AddLine("    vec4 " + GetConstBuffer(index) + "[MAX_CONSTBUFFER_ELEMENTS];");
+            code.AddLine("};");
+            code.AddNewLine();
+        }
+    }
+
+    void DeclareSamplers() {
+        const auto& samplers = ir.GetSamplers();
+        for (const auto& sampler : samplers) {
+            std::string sampler_type = [&]() {
+                switch (sampler.GetType()) {
+                case Tegra::Shader::TextureType::Texture1D:
+                    return "sampler1D";
+                case Tegra::Shader::TextureType::Texture2D:
+                    return "sampler2D";
+                case Tegra::Shader::TextureType::Texture3D:
+                    return "sampler3D";
+                case Tegra::Shader::TextureType::TextureCube:
+                    return "samplerCube";
+                default:
+                    UNREACHABLE();
+                }
+            }();
+            if (sampler.IsArray())
+                sampler_type += "Array";
+            if (sampler.IsShadow())
+                sampler_type += "Shadow";
+
+            code.AddLine("uniform " + sampler_type + ' ' + GetSampler(sampler) + ';');
+        }
+        if (!samplers.empty())
+            code.AddNewLine();
+    }
+
+    void VisitBasicBlock(const BasicBlock& bb) {
+        for (const Node node : bb) {
+            if (const std::string expr = Visit(node); !expr.empty()) {
+                code.AddLine(expr);
+            }
+        }
+    }
+
+    std::string Visit(Node node) {
+        if (const auto operation = std::get_if<OperationNode>(node)) {
+            const auto operation_index = static_cast<std::size_t>(operation->GetCode());
+            const auto decompiler = operation_decompilers[operation_index];
+            if (decompiler == nullptr) {
+                UNREACHABLE_MSG("Operation decompiler {} not defined", operation_index);
+            }
+            return (this->*decompiler)(*operation);
+
+        } else if (const auto gpr = std::get_if<GprNode>(node)) {
+            const u32 index = gpr->GetIndex();
+            if (index == RZ) {
+                return "0";
+            }
+            return GetRegister(index);
+
+        } else if (const auto immediate = std::get_if<ImmediateNode>(node)) {
+            const u32 value = immediate->GetValue();
+            if (value < 10) {
+                // For eyecandy avoid using hex numbers on single digits
+                return fmt::format("utof({}u)", immediate->GetValue());
+            }
+            return fmt::format("utof(0x{:x}u)", immediate->GetValue());
+
+        } else if (const auto predicate = std::get_if<PredicateNode>(node)) {
+            const auto value = [&]() -> std::string {
+                switch (const auto index = predicate->GetIndex(); index) {
+                case Tegra::Shader::Pred::UnusedIndex:
+                    return "true";
+                case Tegra::Shader::Pred::NeverExecute:
+                    return "false";
+                default:
+                    return GetPredicate(index);
+                }
+            }();
+            if (predicate->IsNegated()) {
+                return "!(" + value + ')';
+            }
+            return value;
+
+        } else if (const auto abuf = std::get_if<AbufNode>(node)) {
+            const auto attribute = abuf->GetIndex();
+            const auto element = abuf->GetElement();
+
+            switch (attribute) {
+            case Attribute::Index::Position:
+                return element == 3 ? "1.0f" : "gl_FragCoord" + GetSwizzle(element);
+            case Attribute::Index::PointCoord:
+                switch (element) {
+                case 0:
+                    return "gl_PointCoord.x";
+                case 1:
+                    return "gl_PointCoord.y";
+                case 2:
+                case 3:
+                    return "0";
+                }
+                UNREACHABLE();
+                return "0";
+            case Attribute::Index::TessCoordInstanceIDVertexID:
+                // TODO(Subv): Find out what the values are for the first two elements when inside a
+                // vertex shader, and what's the value of the fourth element when inside a Tess Eval
+                // shader.
+                ASSERT(stage == ShaderStage::Vertex);
+                switch (element) {
+                case 2:
+                    // Config pack's first value is instance_id.
+                    return "uintBitsToFloat(config_pack[0])";
+                case 3:
+                    return "uintBitsToFloat(gl_VertexID)";
+                }
+                UNIMPLEMENTED_MSG("Unmanaged TessCoordInstanceIDVertexID element={}", element);
+                return "0";
+            case Attribute::Index::FrontFacing:
+                // TODO(Subv): Find out what the values are for the other elements.
+                ASSERT(stage == ShaderStage::Fragment);
+                switch (element) {
+                case 3:
+                    return "itof(gl_FrontFacing ? -1 : 0)";
+                }
+                UNIMPLEMENTED_MSG("Unmanaged FrontFacing element={}", element);
+                return "0";
+            default:
+                if (attribute >= Attribute::Index::Attribute_0 &&
+                    attribute <= Attribute::Index::Attribute_31) {
+                    return GetInputAttribute(attribute) + GetSwizzle(abuf->GetElement());
+                }
+                break;
+            }
+            UNIMPLEMENTED_MSG("Unhandled input attribute: {}", static_cast<u32>(attribute));
+
+        } else if (const auto cbuf = std::get_if<CbufNode>(node)) {
+            const Node offset = cbuf->GetOffset();
+            if (const auto immediate = std::get_if<ImmediateNode>(offset)) {
+                // Direct access
+                const u32 offset_imm = immediate->GetValue();
+                return fmt::format("{}[{}][{}]", GetConstBuffer(cbuf->GetIndex()), offset_imm / 4,
+                                   offset_imm % 4);
+
+            } else if (std::holds_alternative<OperationNode>(*offset)) {
+                // Indirect access
+                const std::string final_offset = code.GenerateTemporal();
+                code.AddLine("uint " + final_offset + " = (ftou(" + Visit(offset) + ") / 4) & " +
+                             std::to_string(MAX_CONSTBUFFER_ELEMENTS - 1) + ';');
+                return fmt::format("{}[{} / 4][{} % 4]", GetConstBuffer(cbuf->GetIndex()),
+                                   final_offset, final_offset);
+
+            } else {
+                UNREACHABLE_MSG("Unmanaged offset node type");
+            }
+
+        } else if (const auto lmem = std::get_if<LmemNode>(node)) {
+            return fmt::format("{}[ftou({}) / 4]", GetLocalMemory(), Visit(lmem->GetAddress()));
+
+        } else if (const auto internal_flag = std::get_if<InternalFlagNode>(node)) {
+            return GetInternalFlag(internal_flag->GetFlag());
+
+        } else if (const auto conditional = std::get_if<ConditionalNode>(node)) {
+            // It's invalid to call conditional on nested nodes, use an operation instead
+            code.AddLine("if (" + Visit(conditional->GetCondition()) + ") {");
+            ++code.scope;
+
+            VisitBasicBlock(conditional->GetCode());
+
+            --code.scope;
+            code.AddLine('}');
+            return {};
+
+        } else if (const auto comment = std::get_if<CommentNode>(node)) {
+            return "// " + comment->GetText();
+        }
+        UNREACHABLE();
+    }
+
+    std::string ApplyPrecise(Operation operation, const std::string& value) {
+        if (!IsPrecise(operation)) {
+            return value;
+        }
+        // There's a bug in NVidia's proprietary drivers that makes precise fail on fragment shaders
+        const std::string precise = stage != ShaderStage::Fragment ? "precise " : "";
+
+        const std::string temporal = code.GenerateTemporal();
+        code.AddLine(precise + "float " + temporal + " = " + value + ';');
+        return temporal;
+    }
+
+    std::string VisitOperand(Operation operation, std::size_t operand_index) {
+        const auto& operand = operation[operand_index];
+        const bool parent_precise = IsPrecise(operation);
+        const bool child_precise = IsPrecise(operand);
+        const bool child_trivial = !std::holds_alternative<OperationNode>(*operand);
+        if (!parent_precise || child_precise || child_trivial) {
+            return Visit(operand);
+        }
+
+        const std::string temporal = code.GenerateTemporal();
+        code.AddLine("float " + temporal + " = " + Visit(operand) + ';');
+        return temporal;
+    }
+
+    std::string VisitOperand(Operation operation, std::size_t operand_index, Type type) {
+        std::string value = VisitOperand(operation, operand_index);
+
+        switch (type) {
+        case Type::Bool:
+        case Type::Float:
+            return value;
+        case Type::Int:
+            return "ftoi(" + value + ')';
+        case Type::Uint:
+            return "ftou(" + value + ')';
+        case Type::HalfFloat:
+            if (!std::holds_alternative<MetaHalfArithmetic>(operation.GetMeta())) {
+                value = "toHalf2(" + value + ')';
+            }
+
+            const auto& half_meta = std::get<MetaHalfArithmetic>(operation.GetMeta());
+            switch (half_meta.types.at(operand_index)) {
+            case Tegra::Shader::HalfType::H0_H1:
+                return "toHalf2(" + value + ')';
+            case Tegra::Shader::HalfType::F32:
+                return "vec2(" + value + ')';
+            case Tegra::Shader::HalfType::H0_H0:
+                return "vec2(toHalf2(" + value + ")[0])";
+            case Tegra::Shader::HalfType::H1_H1:
+                return "vec2(toHalf2(" + value + ")[1])";
+            }
+        }
+        UNREACHABLE();
+    }
+
+    std::string BitwiseCastResult(std::string value, Type type, bool needs_parenthesis = false) {
+        switch (type) {
+        case Type::Bool:
+        case Type::Float:
+            if (needs_parenthesis) {
+                return '(' + value + ')';
+            }
+            return value;
+        case Type::Int:
+            return "itof(" + value + ')';
+        case Type::Uint:
+            return "utof(" + value + ')';
+        case Type::HalfFloat:
+            return "fromHalf2(" + value + ')';
+        }
+        UNREACHABLE();
+    }
+
+    std::string GenerateUnary(Operation operation, const std::string& func, Type result_type,
+                              Type type_a, bool needs_parenthesis = true) {
+        return ApplyPrecise(operation,
+                            BitwiseCastResult(func + '(' + VisitOperand(operation, 0, type_a) + ')',
+                                              result_type, needs_parenthesis));
+    }
+
+    std::string GenerateBinaryInfix(Operation operation, const std::string& func, Type result_type,
+                                    Type type_a, Type type_b) {
+        const std::string op_a = VisitOperand(operation, 0, type_a);
+        const std::string op_b = VisitOperand(operation, 1, type_b);
+
+        return ApplyPrecise(
+            operation, BitwiseCastResult('(' + op_a + ' ' + func + ' ' + op_b + ')', result_type));
+    }
+
+    std::string GenerateBinaryCall(Operation operation, const std::string& func, Type result_type,
+                                   Type type_a, Type type_b) {
+        const std::string op_a = VisitOperand(operation, 0, type_a);
+        const std::string op_b = VisitOperand(operation, 1, type_b);
+
+        return ApplyPrecise(operation,
+                            BitwiseCastResult(func + '(' + op_a + ", " + op_b + ')', result_type));
+    }
+
+    std::string GenerateTernary(Operation operation, const std::string& func, Type result_type,
+                                Type type_a, Type type_b, Type type_c) {
+        const std::string op_a = VisitOperand(operation, 0, type_a);
+        const std::string op_b = VisitOperand(operation, 1, type_b);
+        const std::string op_c = VisitOperand(operation, 2, type_c);
+
+        return ApplyPrecise(
+            operation,
+            BitwiseCastResult(func + '(' + op_a + ", " + op_b + ", " + op_c + ')', result_type));
+    }
+
+    std::string GenerateQuaternary(Operation operation, const std::string& func, Type result_type,
+                                   Type type_a, Type type_b, Type type_c, Type type_d) {
+        const std::string op_a = VisitOperand(operation, 0, type_a);
+        const std::string op_b = VisitOperand(operation, 1, type_b);
+        const std::string op_c = VisitOperand(operation, 2, type_c);
+        const std::string op_d = VisitOperand(operation, 3, type_d);
+
+        return ApplyPrecise(operation, BitwiseCastResult(func + '(' + op_a + ", " + op_b + ", " +
+                                                             op_c + ", " + op_d + ')',
+                                                         result_type));
+    }
+
+    std::string GenerateTexture(Operation operation, const std::string& func,
+                                const std::string& extra_cast = "") {
+        constexpr std::array<const char*, 4> coord_constructors = {"float", "vec2", "vec3", "vec4"};
+
+        const auto& meta = std::get<MetaTexture>(operation.GetMeta());
+        const auto count = static_cast<u32>(operation.GetOperandsCount());
+
+        std::string expr = func;
+        expr += '(';
+        expr += GetSampler(meta.sampler);
+        expr += ", ";
+
+        expr += coord_constructors[meta.coords_count - 1];
+        expr += '(';
+        for (u32 i = 0; i < count; ++i) {
+            const bool is_extra = i >= meta.coords_count;
+            const bool do_cast = is_extra && !extra_cast.empty();
+            if (do_cast) {
+                expr += extra_cast;
+                expr += '(';
+            }
+            expr += Visit(operation[i]);
+            if (do_cast) {
+                expr += ')';
+            }
+            if (i + 1 == meta.coords_count) {
+                expr += ')';
+            }
+            if (i + 1 < count) {
+                expr += ", ";
+            }
+        }
+        expr += ')';
+        return expr;
+    }
+
+    std::string Assign(Operation operation) {
+        const Node dest = operation[0];
+        const Node src = operation[1];
+
+        std::string target;
+        if (const auto gpr = std::get_if<GprNode>(dest)) {
+            if (gpr->GetIndex() == RZ) {
+                // Writing to RZ is a no op
+                return {};
+            }
+            target = GetRegister(gpr->GetIndex());
+
+        } else if (const auto abuf = std::get_if<AbufNode>(dest)) {
+            target = [&]() -> std::string {
+                switch (const auto attribute = abuf->GetIndex(); abuf->GetIndex()) {
+                case Attribute::Index::Position:
+                    return "position" + GetSwizzle(abuf->GetElement());
+                case Attribute::Index::PointSize:
+                    return "gl_PointSize";
+                case Attribute::Index::ClipDistances0123:
+                    return "gl_ClipDistance[" + std::to_string(abuf->GetElement()) + ']';
+                case Attribute::Index::ClipDistances4567:
+                    return "gl_ClipDistance[" + std::to_string(abuf->GetElement() + 4) + ']';
+                default:
+                    if (attribute >= Attribute::Index::Attribute_0 &&
+                        attribute <= Attribute::Index::Attribute_31) {
+                        return GetOutputAttribute(attribute) + GetSwizzle(abuf->GetElement());
+                    }
+                    UNIMPLEMENTED_MSG("Unhandled output attribute: {}",
+                                      static_cast<u32>(attribute));
+                }
+            }();
+
+        } else if (const auto lmem = std::get_if<LmemNode>(dest)) {
+            target = GetLocalMemory() + "[ftou(" + Visit(lmem->GetAddress()) + ") / 4]";
+
+        } else {
+            UNREACHABLE_MSG("Assign called without a proper target");
+        }
+
+        code.AddLine(target + " = " + Visit(src) + ';');
+        return {};
+    }
+
+    std::string AssignComposite(Operation operation) {
+        const auto& meta = std::get<MetaComponents>(operation.GetMeta());
+
+        const std::string composite = code.GenerateTemporal();
+        code.AddLine("vec4 " + composite + " = " + Visit(operation[0]) + ';');
+
+        constexpr u32 composite_size = 4;
+        for (u32 i = 0; i < composite_size; ++i) {
+            const auto gpr = std::get<GprNode>(*operation[i + 1]).GetIndex();
+            if (gpr == RZ) {
+                continue;
+            }
+            code.AddLine(GetRegister(gpr) + " = " + composite +
+                         GetSwizzle(meta.GetSourceComponent(i)) + ';');
+        }
+        return {};
+    }
+
+    std::string Composite(Operation operation) {
+        std::string value = "vec4(";
+        for (std::size_t i = 0; i < 4; ++i) {
+            value += Visit(operation[i]);
+            if (i < 3)
+                value += ", ";
+        }
+        value += ')';
+        return value;
+    }
+
+    template <Type type>
+    std::string Add(Operation operation) {
+        return GenerateBinaryInfix(operation, "+", type, type, type);
+    }
+
+    template <Type type>
+    std::string Mul(Operation operation) {
+        return GenerateBinaryInfix(operation, "*", type, type, type);
+    }
+
+    template <Type type>
+    std::string Div(Operation operation) {
+        return GenerateBinaryInfix(operation, "/", type, type, type);
+    }
+
+    std::string FFma(Operation operation) {
+        return GenerateTernary(operation, "fma", Type::Float, Type::Float, Type::Float,
+                               Type::Float);
+    }
+
+    template <Type type>
+    std::string Negate(Operation operation) {
+        return GenerateUnary(operation, "-", type, type, true);
+    }
+
+    template <Type type>
+    std::string Absolute(Operation operation) {
+        return GenerateUnary(operation, "abs", type, type, false);
+    }
+
+    std::string FClamp(Operation operation) {
+        return GenerateTernary(operation, "clamp", Type::Float, Type::Float, Type::Float,
+                               Type::Float);
+    }
+
+    template <Type type>
+    std::string Min(Operation operation) {
+        return GenerateBinaryCall(operation, "min", type, type, type);
+    }
+
+    template <Type type>
+    std::string Max(Operation operation) {
+        return GenerateBinaryCall(operation, "max", type, type, type);
+    }
+
+    std::string Select(Operation operation) {
+        const std::string condition = Visit(operation[0]);
+        const std::string true_case = Visit(operation[1]);
+        const std::string false_case = Visit(operation[2]);
+        return ApplyPrecise(operation,
+                            '(' + condition + " ? " + true_case + " : " + false_case + ')');
+    }
+
+    std::string FCos(Operation operation) {
+        return GenerateUnary(operation, "cos", Type::Float, Type::Float, false);
+    }
+
+    std::string FSin(Operation operation) {
+        return GenerateUnary(operation, "sin", Type::Float, Type::Float, false);
+    }
+
+    std::string FExp2(Operation operation) {
+        return GenerateUnary(operation, "exp2", Type::Float, Type::Float, false);
+    }
+
+    std::string FLog2(Operation operation) {
+        return GenerateUnary(operation, "log2", Type::Float, Type::Float, false);
+    }
+
+    std::string FInverseSqrt(Operation operation) {
+        return GenerateUnary(operation, "inversesqrt", Type::Float, Type::Float, false);
+    }
+
+    std::string FSqrt(Operation operation) {
+        return GenerateUnary(operation, "sqrt", Type::Float, Type::Float, false);
+    }
+
+    std::string FRoundEven(Operation operation) {
+        return GenerateUnary(operation, "roundEven", Type::Float, Type::Float, false);
+    }
+
+    std::string FFloor(Operation operation) {
+        return GenerateUnary(operation, "floor", Type::Float, Type::Float, false);
+    }
+
+    std::string FCeil(Operation operation) {
+        return GenerateUnary(operation, "ceil", Type::Float, Type::Float, false);
+    }
+
+    std::string FTrunc(Operation operation) {
+        return GenerateUnary(operation, "trunc", Type::Float, Type::Float, false);
+    }
+
+    template <Type type>
+    std::string FCastInteger(Operation operation) {
+        return GenerateUnary(operation, "float", Type::Float, type, false);
+    }
+
+    std::string ICastFloat(Operation operation) {
+        return GenerateUnary(operation, "int", Type::Int, Type::Float, false);
+    }
+
+    std::string ICastUnsigned(Operation operation) {
+        return GenerateUnary(operation, "int", Type::Int, Type::Uint, false);
+    }
+
+    template <Type type>
+    std::string LogicalShiftLeft(Operation operation) {
+        return GenerateBinaryInfix(operation, "<<", type, type, Type::Uint);
+    }
+
+    std::string ILogicalShiftRight(Operation operation) {
+        const std::string op_a = VisitOperand(operation, 0, Type::Uint);
+        const std::string op_b = VisitOperand(operation, 1, Type::Uint);
+
+        return ApplyPrecise(operation,
+                            BitwiseCastResult("int(" + op_a + " >> " + op_b + ')', Type::Int));
+    }
+
+    std::string IArithmeticShiftRight(Operation operation) {
+        return GenerateBinaryInfix(operation, ">>", Type::Int, Type::Int, Type::Uint);
+    }
+
+    template <Type type>
+    std::string BitwiseAnd(Operation operation) {
+        return GenerateBinaryInfix(operation, "&", type, type, type);
+    }
+
+    template <Type type>
+    std::string BitwiseOr(Operation operation) {
+        return GenerateBinaryInfix(operation, "|", type, type, type);
+    }
+
+    template <Type type>
+    std::string BitwiseXor(Operation operation) {
+        return GenerateBinaryInfix(operation, "^", type, type, type);
+    }
+
+    template <Type type>
+    std::string BitwiseNot(Operation operation) {
+        return GenerateUnary(operation, "~", type, type, false);
+    }
+
+    std::string UCastFloat(Operation operation) {
+        return GenerateUnary(operation, "uint", Type::Uint, Type::Float, false);
+    }
+
+    std::string UCastSigned(Operation operation) {
+        return GenerateUnary(operation, "uint", Type::Uint, Type::Int, false);
+    }
+
+    std::string UShiftRight(Operation operation) {
+        return GenerateBinaryInfix(operation, ">>", Type::Uint, Type::Uint, Type::Uint);
+    }
+
+    template <Type type>
+    std::string BitfieldInsert(Operation operation) {
+        return GenerateQuaternary(operation, "bitfieldInsert", type, type, type, Type::Int,
+                                  Type::Int);
+    }
+
+    std::string HNegate(Operation operation) {
+        const auto GetNegate = [&](std::size_t index) -> std::string {
+            if (const auto pred = std::get_if<PredicateNode>(operation[index])) {
+                if (!pred->IsNegated()) {
+                    switch (pred->GetIndex()) {
+                    case Tegra::Shader::Pred::UnusedIndex:
+                        return "-1";
+                    case Tegra::Shader::Pred::NeverExecute:
+                        return "1";
+                    }
+                }
+            }
+            return VisitOperand(operation, index, Type::Bool) + " ? -1 : 1";
+        };
+        const std::string value = '(' + VisitOperand(operation, 0, Type::HalfFloat) + " * vec2(" +
+                                  GetNegate(1) + ", " + GetNegate(2) + "))";
+        return BitwiseCastResult(value, Type::HalfFloat);
+    }
+
+    std::string HMergeF32(Operation operation) {
+        return "float(toHalf2(" + Visit(operation[0]) + ")[0])";
+    }
+
+    std::string HMergeH0(Operation operation) {
+        return "fromHalf2(vec2(toHalf2(" + Visit(operation[0]) + ")[1], toHalf2(" +
+               Visit(operation[1]) + ")[0]))";
+    }
+
+    std::string HMergeH1(Operation operation) {
+        return "fromHalf2(vec2(toHalf2(" + Visit(operation[0]) + ")[0], toHalf2(" +
+               Visit(operation[1]) + ")[1]))";
+    }
+
+    template <Type type>
+    std::string LogicalLessThan(Operation operation) {
+        return GenerateBinaryInfix(operation, "<", Type::Bool, type, type);
+    }
+
+    template <Type type>
+    std::string LogicalEqual(Operation operation) {
+        return GenerateBinaryInfix(operation, "==", Type::Bool, type, type);
+    }
+
+    template <Type type>
+    std::string LogicalLessEqual(Operation operation) {
+        return GenerateBinaryInfix(operation, "<=", Type::Bool, type, type);
+    }
+
+    template <Type type>
+    std::string LogicalGreaterThan(Operation operation) {
+        return GenerateBinaryInfix(operation, ">", Type::Bool, type, type);
+    }
+
+    template <Type type>
+    std::string LogicalNotEqual(Operation operation) {
+        return GenerateBinaryInfix(operation, "!=", Type::Bool, type, type);
+    }
+
+    template <Type type>
+    std::string LogicalGreaterEqual(Operation operation) {
+        return GenerateBinaryInfix(operation, ">=", Type::Bool, type, type);
+    }
+
+    std::string LogicalFIsNan(Operation operation) {
+        return GenerateUnary(operation, "isnan", Type::Bool, Type::Float, false);
+    }
+
+    std::string LogicalAssign(Operation operation) {
+        const Node dest = operation[0];
+        const Node src = operation[1];
+
+        std::string target;
+
+        if (const auto pred = std::get_if<PredicateNode>(dest)) {
+            ASSERT_MSG(!pred->IsNegated(), "Negating logical assignment");
+
+            const auto index = pred->GetIndex();
+            switch (index) {
+            case Tegra::Shader::Pred::NeverExecute:
+            case Tegra::Shader::Pred::UnusedIndex:
+                // Writing to these predicates is a no-op
+                return {};
+            }
+            target = GetPredicate(index);
+        } else if (const auto flag = std::get_if<InternalFlagNode>(dest)) {
+            target = GetInternalFlag(flag->GetFlag());
+        }
+
+        code.AddLine(target + " = " + Visit(src) + ';');
+        return {};
+    }
+
+    std::string LogicalAnd(Operation operation) {
+        return GenerateBinaryInfix(operation, "&&", Type::Bool, Type::Bool, Type::Bool);
+    }
+
+    std::string LogicalOr(Operation operation) {
+        return GenerateBinaryInfix(operation, "||", Type::Bool, Type::Bool, Type::Bool);
+    }
+
+    std::string LogicalXor(Operation operation) {
+        return GenerateBinaryInfix(operation, "^^", Type::Bool, Type::Bool, Type::Bool);
+    }
+
+    std::string LogicalNegate(Operation operation) {
+        return GenerateUnary(operation, "!", Type::Bool, Type::Bool, false);
+    }
+
+    std::string LogicalHComparison(Operation operation, const std::string& func) {
+        const auto& meta = std::get<MetaHalfArithmetic>(operation.GetMeta());
+        const std::string op_a = VisitOperand(operation, 0, Type::HalfFloat);
+        const std::string op_b = VisitOperand(operation, 1, Type::HalfFloat);
+
+        std::string value = meta.and_comparison ? "all" : "any";
+        value += '(' + func + '(' + op_a + ", " + op_b + "))";
+        return value;
+    }
+
+    std::string LogicalHLessThan(Operation operation) {
+        return LogicalHComparison(operation, "lessThan");
+    }
+
+    std::string LogicalHEqual(Operation operation) {
+        return LogicalHComparison(operation, "equal");
+    }
+
+    std::string LogicalHLessEqual(Operation operation) {
+        return LogicalHComparison(operation, "lessThanEqual");
+    }
+
+    std::string LogicalHGreaterThan(Operation operation) {
+        return LogicalHComparison(operation, "greaterThan");
+    }
+
+    std::string LogicalHNotEqual(Operation operation) {
+        return LogicalHComparison(operation, "notEqual");
+    }
+
+    std::string LogicalHGreaterEqual(Operation operation) {
+        return LogicalHComparison(operation, "greaterThanEqual");
+    }
+
+    std::string F4Texture(Operation operation) {
+        std::string expr = GenerateTexture(operation, "texture");
+        if (std::get<MetaTexture>(operation.GetMeta()).sampler.IsShadow()) {
+            expr = "vec4(" + expr + ')';
+        }
+        return expr;
+    }
+
+    std::string F4TextureLod(Operation operation) {
+        std::string expr = GenerateTexture(operation, "textureLod");
+        if (std::get<MetaTexture>(operation.GetMeta()).sampler.IsShadow()) {
+            expr = "vec4(" + expr + ')';
+        }
+        return expr;
+    }
+
+    std::string F4TextureGather(Operation operation) {
+        return GenerateTexture(operation, "textureGather", "int");
+    }
+
+    std::string F4TextureQueryDimensions(Operation operation) {
+        const auto& meta = std::get<MetaTexture>(operation.GetMeta());
+        const std::string sampler = GetSampler(meta.sampler);
+        const std::string lod = VisitOperand(operation, 0, Type::Int);
+
+        const std::string sizes = code.GenerateTemporal();
+        code.AddLine("ivec2 " + sizes + " = textureSize(" + sampler + ", " + lod + ");");
+
+        const std::string mip_level = "textureQueryLevels(" + sampler + ')';
+
+        return "itof(ivec4(" + sizes + ", 0, " + mip_level + "))";
+    }
+
+    std::string F4TextureQueryLod(Operation operation) {
+        const std::string tmp = code.GenerateTemporal();
+        code.AddLine("vec2 " + tmp + " = " + GenerateTexture(operation, "textureQueryLod") +
+                     " * vec2(256);");
+
+        return "vec4(itof(int(" + tmp + ".y)), utof(uint(" + tmp + ".x)), 0, 0)";
+    }
+
+    std::string Ipa(Operation operation) {
+        const auto& attribute = operation[0];
+        // TODO(Rodrigo): Special IPA attribute interactions
+        return Visit(attribute);
+    }
+
+    std::string Bra(Operation operation) {
+        const auto target = std::get<ImmediateNode>(*operation[0]);
+        code.AddLine(fmt::format("jmp_to = 0x{:x}u;", target.GetValue()));
+        code.AddLine("break;");
+        return {};
+    }
+
+    std::string PushFlowStack(Operation operation) {
+        const auto target = std::get<ImmediateNode>(*operation[0]);
+        code.AddLine(fmt::format("flow_stack[flow_stack_top] = 0x{:x}u;", target.GetValue()));
+        code.AddLine("flow_stack_top++;");
+        return {};
+    }
+
+    std::string PopFlowStack(Operation operation) {
+        code.AddLine("flow_stack_top--;");
+        code.AddLine("jmp_to = flow_stack[flow_stack_top];");
+        code.AddLine("break;");
+        return {};
+    }
+
+    std::string Exit(Operation operation) {
+        if (stage != ShaderStage::Fragment) {
+            code.AddLine("return;");
+            return {};
+        }
+        const auto& used_registers = ir.GetRegisters();
+        const auto SafeGetRegister = [&](u32 reg) -> std::string {
+            // TODO(Rodrigo): Replace with contains once C++20 releases
+            if (used_registers.find(reg) != used_registers.end()) {
+                return GetRegister(reg);
+            }
+            return "0.0f";
+        };
+
+        UNIMPLEMENTED_IF_MSG(header.ps.omap.sample_mask != 0, "Sample mask write is unimplemented");
+
+        code.AddLine("if (alpha_test[0] != 0) {");
+        ++code.scope;
+        // We start on the register containing the alpha value in the first RT.
+        u32 current_reg = 3;
+        for (u32 render_target = 0; render_target < Maxwell::NumRenderTargets; ++render_target) {
+            // TODO(Blinkhawk): verify the behavior of alpha testing on hardware when
+            // multiple render targets are used.
+            if (header.ps.IsColorComponentOutputEnabled(render_target, 0) ||
+                header.ps.IsColorComponentOutputEnabled(render_target, 1) ||
+                header.ps.IsColorComponentOutputEnabled(render_target, 2) ||
+                header.ps.IsColorComponentOutputEnabled(render_target, 3)) {
+                code.AddLine(
+                    fmt::format("if (!AlphaFunc({})) discard;", SafeGetRegister(current_reg)));
+                current_reg += 4;
+            }
+        }
+        --code.scope;
+        code.AddLine('}');
+
+        // Write the color outputs using the data in the shader registers, disabled
+        // rendertargets/components are skipped in the register assignment.
+        current_reg = 0;
+        for (u32 render_target = 0; render_target < Maxwell::NumRenderTargets; ++render_target) {
+            // TODO(Subv): Figure out how dual-source blending is configured in the Switch.
+            for (u32 component = 0; component < 4; ++component) {
+                if (header.ps.IsColorComponentOutputEnabled(render_target, component)) {
+                    code.AddLine(fmt::format("FragColor{}[{}] = {};", render_target, component,
+                                             SafeGetRegister(current_reg)));
+                    ++current_reg;
+                }
+            }
+        }
+
+        if (header.ps.omap.depth) {
+            // The depth output is always 2 registers after the last color output, and current_reg
+            // already contains one past the last color register.
+            code.AddLine("gl_FragDepth = " + SafeGetRegister(current_reg + 1) + ';');
+        }
+
+        code.AddLine("return;");
+        return {};
+    }
+
+    std::string Kil(Operation operation) {
+        // Enclose "discard" in a conditional, so that GLSL compilation does not complain
+        // about unexecuted instructions that may follow this.
+        code.AddLine("if (true) {");
+        ++code.scope;
+        code.AddLine("discard;");
+        --code.scope;
+        code.AddLine("}");
+        return {};
+    }
+
+    std::string YNegate(Operation operation) {
+        // Config pack's third value is Y_NEGATE's state.
+        return "uintBitsToFloat(config_pack[2])";
+    }
+
+    static constexpr OperationDecompilersArray operation_decompilers = {
+        &Assign,
+        &AssignComposite,
+
+        &Composite,
+        &Select,
+
+        &Add<Type::Float>,
+        &Mul<Type::Float>,
+        &Div<Type::Float>,
+        &FFma,
+        &Negate<Type::Float>,
+        &Absolute<Type::Float>,
+        &FClamp,
+        &Min<Type::Float>,
+        &Max<Type::Float>,
+        &FCos,
+        &FSin,
+        &FExp2,
+        &FLog2,
+        &FInverseSqrt,
+        &FSqrt,
+        &FRoundEven,
+        &FFloor,
+        &FCeil,
+        &FTrunc,
+        &FCastInteger<Type::Int>,
+        &FCastInteger<Type::Uint>,
+
+        &Add<Type::Int>,
+        &Mul<Type::Int>,
+        &Div<Type::Int>,
+        &Negate<Type::Int>,
+        &Absolute<Type::Int>,
+        &Min<Type::Int>,
+        &Max<Type::Int>,
+
+        &ICastFloat,
+        &ICastUnsigned,
+        &LogicalShiftLeft<Type::Int>,
+        &ILogicalShiftRight,
+        &IArithmeticShiftRight,
+        &BitwiseAnd<Type::Int>,
+        &BitwiseOr<Type::Int>,
+        &BitwiseXor<Type::Int>,
+        &BitwiseNot<Type::Int>,
+        &BitfieldInsert<Type::Int>,
+
+        &Add<Type::Uint>,
+        &Mul<Type::Uint>,
+        &Div<Type::Uint>,
+        &Min<Type::Uint>,
+        &Max<Type::Uint>,
+        &UCastFloat,
+        &UCastSigned,
+        &LogicalShiftLeft<Type::Uint>,
+        &UShiftRight,
+        &UShiftRight,
+        &BitwiseAnd<Type::Uint>,
+        &BitwiseOr<Type::Uint>,
+        &BitwiseXor<Type::Uint>,
+        &BitwiseNot<Type::Uint>,
+        &BitfieldInsert<Type::Uint>,
+
+        &Add<Type::HalfFloat>,
+        &Mul<Type::HalfFloat>,
+        &Absolute<Type::HalfFloat>,
+        &HNegate,
+        &HMergeF32,
+        &HMergeH0,
+        &HMergeH1,
+
+        &LogicalAssign,
+        &LogicalAnd,
+        &LogicalOr,
+        &LogicalXor,
+        &LogicalNegate,
+
+        &LogicalLessThan<Type::Float>,
+        &LogicalEqual<Type::Float>,
+        &LogicalLessEqual<Type::Float>,
+        &LogicalGreaterThan<Type::Float>,
+        &LogicalNotEqual<Type::Float>,
+        &LogicalGreaterEqual<Type::Float>,
+        &LogicalFIsNan,
+
+        &LogicalLessThan<Type::Int>,
+        &LogicalEqual<Type::Int>,
+        &LogicalLessEqual<Type::Int>,
+        &LogicalGreaterThan<Type::Int>,
+        &LogicalNotEqual<Type::Int>,
+        &LogicalGreaterEqual<Type::Int>,
+
+        &LogicalLessThan<Type::Uint>,
+        &LogicalEqual<Type::Uint>,
+        &LogicalLessEqual<Type::Uint>,
+        &LogicalGreaterThan<Type::Uint>,
+        &LogicalNotEqual<Type::Uint>,
+        &LogicalGreaterEqual<Type::Uint>,
+
+        &LogicalHLessThan,
+        &LogicalHEqual,
+        &LogicalHLessEqual,
+        &LogicalHGreaterThan,
+        &LogicalHNotEqual,
+        &LogicalHGreaterEqual,
+
+        &F4Texture,
+        &F4TextureLod,
+        &F4TextureGather,
+        &F4TextureQueryDimensions,
+        &F4TextureQueryLod,
+
+        &Ipa,
+
+        &Bra,
+        &PushFlowStack, // Ssy
+        &PushFlowStack, // Brk
+        &PopFlowStack,  // Sync
+        &PopFlowStack,  // Brk
+        &Exit,
+        &Kil,
+
+        &YNegate,
+    };
+
+    std::string GetRegister(u32 index) const {
+        return GetDeclarationWithSuffix(index, "gpr");
+    }
+
+    std::string GetPredicate(Tegra::Shader::Pred pred) const {
+        return GetDeclarationWithSuffix(static_cast<u32>(pred), "pred");
+    }
+
+    std::string GetInputAttribute(Attribute::Index attribute) const {
+        const auto index{static_cast<u32>(attribute) -
+                         static_cast<u32>(Attribute::Index::Attribute_0)};
+        return GetDeclarationWithSuffix(index, "input_attr");
+    }
+
+    std::string GetOutputAttribute(Attribute::Index attribute) const {
+        const auto index{static_cast<u32>(attribute) -
+                         static_cast<u32>(Attribute::Index::Attribute_0)};
+        return GetDeclarationWithSuffix(index, "output_attr");
+    }
+
+    std::string GetConstBuffer(u32 index) const {
+        return GetDeclarationWithSuffix(index, "cbuf");
+    }
+
+    std::string GetConstBufferBlock(u32 index) const {
+        return GetDeclarationWithSuffix(index, "cbuf_block");
+    }
+
+    std::string GetLocalMemory() const {
+        return "lmem_" + suffix;
+    }
+
+    std::string GetInternalFlag(InternalFlag flag) const {
+        constexpr std::array<const char*, 4> InternalFlagNames = {"zero_flag", "sign_flag",
+                                                                  "carry_flag", "overflow_flag"};
+        const auto index = static_cast<u32>(flag);
+        ASSERT(index < static_cast<u32>(InternalFlag::Amount));
+
+        return std::string(InternalFlagNames[index]) + '_' + suffix;
+    }
+
+    std::string GetSampler(const Sampler& sampler) const {
+        return GetDeclarationWithSuffix(sampler.GetIndex(), "sampler");
+    }
+
+    std::string GetDeclarationWithSuffix(u32 index, const std::string& name) const {
+        return name + '_' + std::to_string(index) + '_' + suffix;
+    }
+
+    const ShaderIR& ir;
+    const ShaderStage stage;
+    const std::string suffix;
+    const Header header;
+
+    ShaderWriter code;
+};
+
+std::string GetCommonDeclarations() {
+    return "#define MAX_CONSTBUFFER_ELEMENTS " + std::to_string(MAX_CONSTBUFFER_ELEMENTS) +
+           "\n"
+           "#define ftoi floatBitsToInt\n"
+           "#define ftou floatBitsToUint\n"
+           "#define itof intBitsToFloat\n"
+           "#define utof uintBitsToFloat\n\n"
+           "float fromHalf2(vec2 pair) {\n"
+           "    return utof(packHalf2x16(pair));\n"
+           "}\n\n"
+           "vec2 toHalf2(float value) {\n"
+           "    return unpackHalf2x16(ftou(value));\n"
+           "}\n\n";
+}
+
+ProgramResult Decompile(const ShaderIR& ir, Maxwell::ShaderStage stage, const std::string& suffix) {
+    GLSLDecompiler decompiler(ir, stage, suffix);
+    decompiler.Decompile();
+    return {decompiler.GetResult(), decompiler.GetShaderEntries()};
+}
+
+} // namespace OpenGL::GLShader
\ No newline at end of file
diff --git a/src/video_core/shader/glsl_decompiler.h b/src/video_core/shader/glsl_decompiler.h
new file mode 100644
index 000000000..7be461f1b
--- /dev/null
+++ b/src/video_core/shader/glsl_decompiler.h
@@ -0,0 +1,88 @@
+// Copyright 2018 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <array>
+#include <string>
+#include <utility>
+#include <vector>
+#include "common/common_types.h"
+#include "video_core/engines/maxwell_3d.h"
+#include "video_core/shader/shader_ir.h"
+
+namespace VideoCommon::Shader {
+class ShaderIR;
+}
+
+namespace OpenGL::GLShader {
+
+using Maxwell = Tegra::Engines::Maxwell3D::Regs;
+
+class ConstBufferEntry : public VideoCommon::Shader::ConstBuffer {
+public:
+    explicit ConstBufferEntry(const VideoCommon::Shader::ConstBuffer& entry,
+                              Maxwell::ShaderStage stage, const std::string& name, u32 index)
+        : VideoCommon::Shader::ConstBuffer{entry}, stage{stage}, name{name}, index{index} {}
+
+    const std::string& GetName() const {
+        return name;
+    }
+
+    Maxwell::ShaderStage GetStage() const {
+        return stage;
+    }
+
+    u32 GetIndex() const {
+        return index;
+    }
+
+    u32 GetHash() const {
+        return (static_cast<u32>(stage) << 16) | index;
+    }
+
+private:
+    std::string name;
+    Maxwell::ShaderStage stage{};
+    u32 index{};
+};
+
+class SamplerEntry : public VideoCommon::Shader::Sampler {
+public:
+    explicit SamplerEntry(const VideoCommon::Shader::Sampler& entry, Maxwell::ShaderStage stage,
+                          const std::string& name)
+        : VideoCommon::Shader::Sampler{entry}, stage{stage}, name{name} {}
+
+    const std::string& GetName() const {
+        return name;
+    }
+
+    Maxwell::ShaderStage GetStage() const {
+        return stage;
+    }
+
+    u32 GetHash() const {
+        return (static_cast<u32>(stage) << 16) | GetIndex();
+    }
+
+private:
+    std::string name;
+    Maxwell::ShaderStage stage{};
+};
+
+struct ShaderEntries {
+    std::vector<ConstBufferEntry> const_buffers;
+    std::vector<SamplerEntry> samplers;
+    std::array<bool, Maxwell::NumClipDistances> clip_distances{};
+    std::size_t shader_length{};
+};
+
+using ProgramResult = std::pair<std::string, ShaderEntries>;
+
+std::string GetCommonDeclarations();
+
+ProgramResult Decompile(const VideoCommon::Shader::ShaderIR& ir, Maxwell::ShaderStage stage,
+                        const std::string& suffix);
+
+} // namespace OpenGL::GLShader
\ No newline at end of file