Merge pull request #344 from bunnei/shader-decompiler-p2

Shader decompiler changes part 2

4 files changed, 180 insertions, 73 deletions

diff --git a/src/common/bit_field.h b/src/common/bit_field.h
index 5638bdbba..65e357dec 100644
--- a/src/common/bit_field.h
+++ b/src/common/bit_field.h
@@ -192,11 +192,6 @@ private:
     static_assert(position < 8 * sizeof(T), "Invalid position");
     static_assert(bits <= 8 * sizeof(T), "Invalid number of bits");
     static_assert(bits > 0, "Invalid number of bits");
-    static_assert(std::is_pod<T>::value, "Invalid base type");
+    static_assert(std::is_trivially_copyable_v<T>, "T must be trivially copyable in a BitField");
 };
 #pragma pack()
-
-#if (__GNUC__ >= 5) || defined(__clang__) || defined(_MSC_VER)
-static_assert(std::is_trivially_copyable<BitField<0, 1, unsigned>>::value,
-              "BitField must be trivially copyable");
-#endif
diff --git a/src/video_core/engines/shader_bytecode.h b/src/video_core/engines/shader_bytecode.h
index eff0c35a1..ed66d893a 100644
--- a/src/video_core/engines/shader_bytecode.h
+++ b/src/video_core/engines/shader_bytecode.h
@@ -4,6 +4,7 @@
 
 #pragma once
 
+#include <cstring>
 #include <map>
 #include <string>
 #include "common/bit_field.h"
@@ -12,14 +13,10 @@ namespace Tegra {
 namespace Shader {
 
 struct Register {
-    Register() = default;
+    constexpr Register() = default;
 
     constexpr Register(u64 value) : value(value) {}
 
-    constexpr u64 GetIndex() const {
-        return value;
-    }
-
     constexpr operator u64() const {
         return value;
     }
@@ -43,13 +40,13 @@ struct Register {
     }
 
 private:
-    u64 value;
+    u64 value{};
 };
 
 union Attribute {
     Attribute() = default;
 
-    constexpr Attribute(u64 value) : value(value) {}
+    constexpr explicit Attribute(u64 value) : value(value) {}
 
     enum class Index : u64 {
         Position = 7,
@@ -68,7 +65,20 @@ union Attribute {
     } fmt28;
 
     BitField<39, 8, u64> reg;
-    u64 value;
+    u64 value{};
+};
+
+union Sampler {
+    Sampler() = default;
+
+    constexpr explicit Sampler(u64 value) : value(value) {}
+
+    enum class Index : u64 {
+        Sampler_0 = 8,
+    };
+
+    BitField<36, 13, Index> index;
+    u64 value{};
 };
 
 union Uniform {
@@ -238,7 +248,7 @@ union OpCode {
     BitField<55, 9, Id> op3;
     BitField<52, 12, Id> op4;
     BitField<51, 13, Id> op5;
-    u64 value;
+    u64 value{};
 };
 static_assert(sizeof(OpCode) == 0x8, "Incorrect structure size");
 
@@ -280,6 +290,7 @@ enum class SubOp : u64 {
     Lg2 = 0x3,
     Rcp = 0x4,
     Rsq = 0x5,
+    Min = 0x8,
 };
 
 union Instruction {
@@ -295,15 +306,25 @@ union Instruction {
     BitField<20, 8, Register> gpr20;
     BitField<20, 7, SubOp> sub_op;
     BitField<28, 8, Register> gpr28;
-    BitField<36, 13, u64> imm36;
     BitField<39, 8, Register> gpr39;
 
     union {
+        BitField<20, 19, u64> imm20;
         BitField<45, 1, u64> negate_b;
         BitField<46, 1, u64> abs_a;
         BitField<48, 1, u64> negate_a;
         BitField<49, 1, u64> abs_b;
         BitField<50, 1, u64> abs_d;
+        BitField<56, 1, u64> negate_imm;
+
+        float GetImm20() const {
+            float result{};
+            u32 imm{static_cast<u32>(imm20)};
+            imm <<= 12;
+            imm |= negate_imm ? 0x80000000 : 0;
+            std::memcpy(&result, &imm, sizeof(imm));
+            return result;
+        }
     } alu;
 
     union {
@@ -311,11 +332,13 @@ union Instruction {
         BitField<49, 1, u64> negate_c;
     } ffma;
 
+    BitField<61, 1, u64> is_b_imm;
     BitField<60, 1, u64> is_b_gpr;
     BitField<59, 1, u64> is_c_gpr;
 
     Attribute attribute;
     Uniform uniform;
+    Sampler sampler;
 
     u64 hex;
 };
diff --git a/src/video_core/renderer_opengl/gl_shader_decompiler.cpp b/src/video_core/renderer_opengl/gl_shader_decompiler.cpp
index e11711533..6233ee358 100644
--- a/src/video_core/renderer_opengl/gl_shader_decompiler.cpp
+++ b/src/video_core/renderer_opengl/gl_shader_decompiler.cpp
@@ -17,6 +17,7 @@ using Tegra::Shader::Attribute;
 using Tegra::Shader::Instruction;
 using Tegra::Shader::OpCode;
 using Tegra::Shader::Register;
+using Tegra::Shader::Sampler;
 using Tegra::Shader::SubOp;
 using Tegra::Shader::Uniform;
 
@@ -155,23 +156,27 @@ private:
 
     /// Generates code representing an input attribute register.
     std::string GetInputAttribute(Attribute::Index attribute) {
-        declr_input_attribute.insert(attribute);
+        switch (attribute) {
+        case Attribute::Index::Position:
+            return "position";
+        default:
+            const u32 index{static_cast<u32>(attribute) -
+                            static_cast<u32>(Attribute::Index::Attribute_0)};
+            if (attribute >= Attribute::Index::Attribute_0) {
+                declr_input_attribute.insert(attribute);
+                return "input_attribute_" + std::to_string(index);
+            }
 
-        const u32 index{static_cast<u32>(attribute) -
-                        static_cast<u32>(Attribute::Index::Attribute_0)};
-        if (attribute >= Attribute::Index::Attribute_0) {
-            return "input_attribute_" + std::to_string(index);
+            NGLOG_CRITICAL(HW_GPU, "Unhandled input attribute: {}", index);
+            UNREACHABLE();
         }
-
-        LOG_CRITICAL(HW_GPU, "Unhandled input attribute: 0x%02x", index);
-        UNREACHABLE();
     }
 
     /// Generates code representing an output attribute register.
     std::string GetOutputAttribute(Attribute::Index attribute) {
         switch (attribute) {
         case Attribute::Index::Position:
-            return "gl_Position";
+            return "position";
         default:
             const u32 index{static_cast<u32>(attribute) -
                             static_cast<u32>(Attribute::Index::Attribute_0)};
@@ -180,22 +185,42 @@ private:
                 return "output_attribute_" + std::to_string(index);
             }
 
-            LOG_CRITICAL(HW_GPU, "Unhandled output attribute: 0x%02x", index);
+            NGLOG_CRITICAL(HW_GPU, "Unhandled output attribute: {}", index);
             UNREACHABLE();
         }
     }
 
+    /// Generates code representing an immediate value
+    static std::string GetImmediate(const Instruction& instr) {
+        return std::to_string(instr.alu.GetImm20());
+    }
+
     /// Generates code representing a temporary (GPR) register.
-    std::string GetRegister(const Register& reg) {
-        return *declr_register.insert("register_" + std::to_string(reg)).first;
+    std::string GetRegister(const Register& reg, unsigned elem = 0) {
+        if (stage == Maxwell3D::Regs::ShaderStage::Fragment && reg < 4) {
+            // GPRs 0-3 are output color for the fragment shader
+            return std::string{"color."} + "rgba"[(reg + elem) & 3];
+        }
+
+        return *declr_register.insert("register_" + std::to_string(reg + elem)).first;
     }
 
     /// Generates code representing a uniform (C buffer) register.
     std::string GetUniform(const Uniform& reg) {
-        declr_const_buffers[reg.index].MarkAsUsed(reg.index, reg.offset, stage);
+        declr_const_buffers[reg.index].MarkAsUsed(static_cast<unsigned>(reg.index),
+                                                  static_cast<unsigned>(reg.offset), stage);
         return 'c' + std::to_string(reg.index) + '[' + std::to_string(reg.offset) + ']';
     }
 
+    /// Generates code representing a texture sampler.
+    std::string GetSampler(const Sampler& sampler) const {
+        // TODO(Subv): Support more than just texture sampler 0
+        ASSERT_MSG(sampler.index == Sampler::Index::Sampler_0, "unsupported");
+        const unsigned index{static_cast<unsigned>(sampler.index.Value()) -
+                             static_cast<unsigned>(Sampler::Index::Sampler_0)};
+        return "tex[" + std::to_string(index) + "]";
+    }
+
     /**
      * Adds code that calls a subroutine.
      * @param subroutine the subroutine to call.
@@ -217,12 +242,13 @@ private:
      * @param value the code representing the value to assign.
      */
     void SetDest(u64 elem, const std::string& reg, const std::string& value,
-                 u64 dest_num_components, u64 value_num_components) {
+                 u64 dest_num_components, u64 value_num_components, bool is_abs = false) {
         std::string swizzle = ".";
         swizzle += "xyzw"[elem];
 
         std::string dest = reg + (dest_num_components != 1 ? swizzle : "");
         std::string src = "(" + value + ")" + (value_num_components != 1 ? swizzle : "");
+        src = is_abs ? "abs(" + src + ")" : src;
 
         shader.AddLine(dest + " = " + src + ";");
     }
@@ -240,8 +266,6 @@ private:
 
         switch (OpCode::GetInfo(instr.opcode).type) {
         case OpCode::Type::Arithmetic: {
-            ASSERT(!instr.alu.abs_d);
-
             std::string dest = GetRegister(instr.gpr0);
             std::string op_a = instr.alu.negate_a ? "-" : "";
             op_a += GetRegister(instr.gpr8);
@@ -250,63 +274,109 @@ private:
             }
 
             std::string op_b = instr.alu.negate_b ? "-" : "";
-            if (instr.is_b_gpr) {
-                op_b += GetRegister(instr.gpr20);
+
+            if (instr.is_b_imm) {
+                op_b += GetImmediate(instr);
             } else {
-                op_b += GetUniform(instr.uniform);
+                if (instr.is_b_gpr) {
+                    op_b += GetRegister(instr.gpr20);
+                } else {
+                    op_b += GetUniform(instr.uniform);
+                }
             }
+
             if (instr.alu.abs_b) {
                 op_b = "abs(" + op_b + ")";
             }
 
             switch (instr.opcode.EffectiveOpCode()) {
             case OpCode::Id::FMUL_C:
-            case OpCode::Id::FMUL_R: {
-                SetDest(0, dest, op_a + " * " + op_b, 1, 1);
+            case OpCode::Id::FMUL_R:
+            case OpCode::Id::FMUL_IMM: {
+                SetDest(0, dest, op_a + " * " + op_b, 1, 1, instr.alu.abs_d);
                 break;
             }
             case OpCode::Id::FADD_C:
-            case OpCode::Id::FADD_R: {
-                SetDest(0, dest, op_a + " + " + op_b, 1, 1);
+            case OpCode::Id::FADD_R:
+            case OpCode::Id::FADD_IMM: {
+                SetDest(0, dest, op_a + " + " + op_b, 1, 1, instr.alu.abs_d);
                 break;
             }
-            default: {
-                LOG_CRITICAL(HW_GPU, "Unhandled arithmetic instruction: 0x%02x (%s): 0x%08x",
-                             static_cast<unsigned>(instr.opcode.EffectiveOpCode()),
-                             OpCode::GetInfo(instr.opcode).name.c_str(), instr.hex);
-                throw DecompileFail("Unhandled instruction");
+            case OpCode::Id::MUFU: {
+                switch (instr.sub_op) {
+                case SubOp::Cos:
+                    SetDest(0, dest, "cos(" + op_a + ")", 1, 1, instr.alu.abs_d);
+                    break;
+                case SubOp::Sin:
+                    SetDest(0, dest, "sin(" + op_a + ")", 1, 1, instr.alu.abs_d);
+                    break;
+                case SubOp::Ex2:
+                    SetDest(0, dest, "exp2(" + op_a + ")", 1, 1, instr.alu.abs_d);
+                    break;
+                case SubOp::Lg2:
+                    SetDest(0, dest, "log2(" + op_a + ")", 1, 1, instr.alu.abs_d);
+                    break;
+                case SubOp::Rcp:
+                    SetDest(0, dest, "1.0 / " + op_a, 1, 1, instr.alu.abs_d);
+                    break;
+                case SubOp::Rsq:
+                    SetDest(0, dest, "inversesqrt(" + op_a + ")", 1, 1, instr.alu.abs_d);
+                    break;
+                case SubOp::Min:
+                    SetDest(0, dest, "min(" + op_a + "," + op_b + ")", 1, 1, instr.alu.abs_d);
+                    break;
+                default:
+                    NGLOG_CRITICAL(HW_GPU, "Unhandled MUFU sub op: {}",
+                                   static_cast<unsigned>(instr.sub_op.Value()));
+                    UNREACHABLE();
+                }
                 break;
             }
+            default: {
+                NGLOG_CRITICAL(HW_GPU, "Unhandled arithmetic instruction: {} ({}): {}",
+                               static_cast<unsigned>(instr.opcode.EffectiveOpCode()),
+                               OpCode::GetInfo(instr.opcode).name, instr.hex);
+                UNREACHABLE();
+            }
             }
             break;
         }
         case OpCode::Type::Ffma: {
-            ASSERT_MSG(!instr.ffma.negate_b, "untested");
-            ASSERT_MSG(!instr.ffma.negate_c, "untested");
-
             std::string dest = GetRegister(instr.gpr0);
             std::string op_a = GetRegister(instr.gpr8);
-
             std::string op_b = instr.ffma.negate_b ? "-" : "";
-            op_b += GetUniform(instr.uniform);
-
             std::string op_c = instr.ffma.negate_c ? "-" : "";
-            op_c += GetRegister(instr.gpr39);
 
             switch (instr.opcode.EffectiveOpCode()) {
             case OpCode::Id::FFMA_CR: {
-                SetDest(0, dest, op_a + " * " + op_b + " + " + op_c, 1, 1);
+                op_b += GetUniform(instr.uniform);
+                op_c += GetRegister(instr.gpr39);
                 break;
             }
-
-            default: {
-                LOG_CRITICAL(HW_GPU, "Unhandled arithmetic FFMA instruction: 0x%02x (%s): 0x%08x",
-                             static_cast<unsigned>(instr.opcode.EffectiveOpCode()),
-                             OpCode::GetInfo(instr.opcode).name.c_str(), instr.hex);
-                throw DecompileFail("Unhandled instruction");
+            case OpCode::Id::FFMA_RR: {
+                op_b += GetRegister(instr.gpr20);
+                op_c += GetRegister(instr.gpr39);
+                break;
+            }
+            case OpCode::Id::FFMA_RC: {
+                op_b += GetRegister(instr.gpr39);
+                op_c += GetUniform(instr.uniform);
                 break;
             }
+            case OpCode::Id::FFMA_IMM: {
+                op_b += GetImmediate(instr);
+                op_c += GetRegister(instr.gpr39);
+                break;
             }
+            default: {
+                NGLOG_CRITICAL(HW_GPU, "Unhandled FFMA instruction: {} ({}): {}",
+                               static_cast<unsigned>(instr.opcode.EffectiveOpCode()),
+                               OpCode::GetInfo(instr.opcode).name, instr.hex);
+                UNREACHABLE();
+            }
+            }
+
+            SetDest(0, dest, op_a + " * " + op_b + " + " + op_c, 1, 1);
             break;
         }
         case OpCode::Type::Memory: {
@@ -315,22 +385,33 @@ private:
 
             switch (instr.opcode.EffectiveOpCode()) {
             case OpCode::Id::LD_A: {
-                ASSERT(instr.attribute.fmt20.size == 0);
+                ASSERT_MSG(instr.attribute.fmt20.size == 0, "untested");
                 SetDest(instr.attribute.fmt20.element, gpr0, GetInputAttribute(attribute), 1, 4);
                 break;
             }
             case OpCode::Id::ST_A: {
-                ASSERT(instr.attribute.fmt20.size == 0);
+                ASSERT_MSG(instr.attribute.fmt20.size == 0, "untested");
                 SetDest(instr.attribute.fmt20.element, GetOutputAttribute(attribute), gpr0, 4, 1);
                 break;
             }
-            default: {
-                LOG_CRITICAL(HW_GPU, "Unhandled memory instruction: 0x%02x (%s): 0x%08x",
-                             static_cast<unsigned>(instr.opcode.EffectiveOpCode()),
-                             OpCode::GetInfo(instr.opcode).name.c_str(), instr.hex);
-                throw DecompileFail("Unhandled instruction");
+            case OpCode::Id::TEXS: {
+                ASSERT_MSG(instr.attribute.fmt20.size == 4, "untested");
+                const std::string op_a = GetRegister(instr.gpr8);
+                const std::string op_b = GetRegister(instr.gpr20);
+                const std::string sampler = GetSampler(instr.sampler);
+                const std::string coord = "vec2(" + op_a + ", " + op_b + ")";
+                const std::string texture = "texture(" + sampler + ", " + coord + ")";
+                for (unsigned elem = 0; elem < instr.attribute.fmt20.size; ++elem) {
+                    SetDest(elem, GetRegister(instr.gpr0, elem), texture, 1, 4);
+                }
                 break;
             }
+            default: {
+                NGLOG_CRITICAL(HW_GPU, "Unhandled memory instruction: {} ({}): {}",
+                               static_cast<unsigned>(instr.opcode.EffectiveOpCode()),
+                               OpCode::GetInfo(instr.opcode).name, instr.hex);
+                UNREACHABLE();
+            }
             }
             break;
         }
@@ -342,14 +423,18 @@ private:
                 offset = PROGRAM_END - 1;
                 break;
             }
-
-            default: {
-                LOG_CRITICAL(HW_GPU, "Unhandled instruction: 0x%02x (%s): 0x%08x",
-                             static_cast<unsigned>(instr.opcode.EffectiveOpCode()),
-                             OpCode::GetInfo(instr.opcode).name.c_str(), instr.hex);
-                throw DecompileFail("Unhandled instruction");
+            case OpCode::Id::IPA: {
+                const auto& attribute = instr.attribute.fmt28;
+                std::string dest = GetRegister(instr.gpr0);
+                SetDest(attribute.element, dest, GetInputAttribute(attribute.index), 1, 4);
                 break;
             }
+            default: {
+                NGLOG_CRITICAL(HW_GPU, "Unhandled instruction: {} ({}): {}",
+                               static_cast<unsigned>(instr.opcode.EffectiveOpCode()),
+                               OpCode::GetInfo(instr.opcode).name, instr.hex);
+                UNREACHABLE();
+            }
             }
 
             break;
@@ -514,7 +599,7 @@ boost::optional<ProgramResult> DecompileProgram(const ProgramCode& program_code,
         GLSLGenerator generator(subroutines, program_code, main_offset, stage);
         return ProgramResult{generator.GetShaderCode(), generator.GetEntries()};
     } catch (const DecompileFail& exception) {
-        LOG_ERROR(HW_GPU, "Shader decompilation failed: %s", exception.what());
+        NGLOG_ERROR(HW_GPU, "Shader decompilation failed: {}", exception.what());
     }
     return boost::none;
 }
diff --git a/src/video_core/renderer_opengl/gl_shader_gen.cpp b/src/video_core/renderer_opengl/gl_shader_gen.cpp
index aeea1c805..8b7f17601 100644
--- a/src/video_core/renderer_opengl/gl_shader_gen.cpp
+++ b/src/video_core/renderer_opengl/gl_shader_gen.cpp
@@ -27,10 +27,13 @@ out gl_PerVertex {
     vec4 gl_Position;
 };
 
+out vec4 position;
+
 void main() {
     exec_shader();
-}
 
+    gl_Position = position;
+}
 )";
     out += program.first;
     return {out, program.second};
@@ -46,6 +49,7 @@ ProgramResult GenerateFragmentShader(const ShaderSetup& setup, const MaxwellFSCo
                                 .get_value_or({});
     out += R"(
 
+in vec4 position;
 out vec4 color;
 
 uniform sampler2D tex[32];