glsl: Rework variable allocator to allow for variable reuse

1 files changed, 290 insertions, 0 deletions

diff --git a/src/shader_recompiler/backend/glsl/var_alloc.cpp b/src/shader_recompiler/backend/glsl/var_alloc.cpp
new file mode 100644
index 000000000..8c6944f07
--- /dev/null
+++ b/src/shader_recompiler/backend/glsl/var_alloc.cpp
@@ -0,0 +1,290 @@
+// Copyright 2021 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <string>
+#include <string_view>
+
+#include <fmt/format.h>
+
+#include "shader_recompiler/backend/glsl/var_alloc.h"
+#include "shader_recompiler/exception.h"
+#include "shader_recompiler/frontend/ir/value.h"
+
+namespace Shader::Backend::GLSL {
+namespace {
+std::string TypePrefix(GlslVarType type) {
+    switch (type) {
+    case GlslVarType::U1:
+        return "b_";
+    case GlslVarType::F16x2:
+        return "f16x2_";
+    case GlslVarType::U32:
+        return "u_";
+    case GlslVarType::S32:
+        return "s_";
+    case GlslVarType::F32:
+        return "f_";
+    case GlslVarType::S64:
+        return "s64_";
+    case GlslVarType::U64:
+        return "u64_";
+    case GlslVarType::F64:
+        return "d_";
+    case GlslVarType::U32x2:
+        return "u2_";
+    case GlslVarType::F32x2:
+        return "f2_";
+    case GlslVarType::U32x3:
+        return "u3_";
+    case GlslVarType::F32x3:
+        return "f3_";
+    case GlslVarType::U32x4:
+        return "u4_";
+    case GlslVarType::F32x4:
+        return "f4_";
+    case GlslVarType::Void:
+        return "";
+    default:
+        throw NotImplementedException("Type {}", type);
+    }
+}
+
+std::string FormatFloat(std::string_view value, IR::Type type) {
+    // TODO: Confirm FP64 nan/inf
+    if (type == IR::Type::F32) {
+        if (value == "nan") {
+            return "uintBitsToFloat(0x7fc00000)";
+        }
+        if (value == "inf") {
+            return "uintBitsToFloat(0x7f800000)";
+        }
+        if (value == "-inf") {
+            return "uintBitsToFloat(0xff800000)";
+        }
+    }
+    if (value.find_first_of('e') != std::string_view::npos) {
+        // scientific notation
+        const auto cast{type == IR::Type::F32 ? "float" : "double"};
+        return fmt::format("{}({})", cast, value);
+    }
+    const bool needs_dot{value.find_first_of('.') == std::string_view::npos};
+    const bool needs_suffix{!value.ends_with('f')};
+    const auto suffix{type == IR::Type::F32 ? "f" : "lf"};
+    return fmt::format("{}{}{}", value, needs_dot ? "." : "", needs_suffix ? suffix : "");
+}
+
+std::string MakeImm(const IR::Value& value) {
+    switch (value.Type()) {
+    case IR::Type::U1:
+        return fmt::format("{}", value.U1() ? "true" : "false");
+    case IR::Type::U32:
+        return fmt::format("{}u", value.U32());
+    case IR::Type::F32:
+        return FormatFloat(fmt::format("{}", value.F32()), IR::Type::F32);
+    case IR::Type::U64:
+        return fmt::format("{}ul", value.U64());
+    case IR::Type::F64:
+        return FormatFloat(fmt::format("{}", value.F64()), IR::Type::F64);
+    case IR::Type::Void:
+        return "";
+    default:
+        throw NotImplementedException("Immediate type {}", value.Type());
+    }
+}
+} // Anonymous namespace
+
+std::string VarAlloc::Representation(u32 index, GlslVarType type) const {
+    const auto prefix{TypePrefix(type)};
+    return fmt::format("{}{}", prefix, index);
+}
+
+std::string VarAlloc::Representation(Id id) const {
+    return Representation(id.index, id.type);
+}
+
+std::string VarAlloc::Define(IR::Inst& inst, GlslVarType type) {
+    if (inst.HasUses()) {
+        inst.SetDefinition<Id>(Alloc(type));
+        return Representation(inst.Definition<Id>());
+    } else {
+        Id id{};
+        id.type.Assign(type);
+        // id.is_null.Assign(1);
+        GetUseTracker(type).uses_temp = true;
+        inst.SetDefinition<Id>(id);
+    }
+    return Representation(inst.Definition<Id>());
+}
+
+std::string VarAlloc::Define(IR::Inst& inst, IR::Type type) {
+    return Define(inst, RegType(type));
+}
+
+std::string VarAlloc::Consume(const IR::Value& value) {
+    return value.IsImmediate() ? MakeImm(value) : ConsumeInst(*value.InstRecursive());
+}
+
+std::string VarAlloc::ConsumeInst(IR::Inst& inst) {
+    inst.DestructiveRemoveUsage();
+    if (!inst.HasUses()) {
+        Free(inst.Definition<Id>());
+    }
+    return Representation(inst.Definition<Id>());
+}
+
+std::string VarAlloc::GetGlslType(IR::Type type) const {
+    return GetGlslType(RegType(type));
+}
+
+Id VarAlloc::Alloc(GlslVarType type) {
+    auto& use_tracker{GetUseTracker(type)};
+    if (use_tracker.num_used < NUM_VARS) {
+        for (size_t var = 1; var < NUM_VARS; ++var) {
+            if (use_tracker.var_use[var]) {
+                continue;
+            }
+            use_tracker.num_used = std::max(use_tracker.num_used, var + 1);
+            use_tracker.var_use[var] = true;
+            Id ret{};
+            ret.is_valid.Assign(1);
+            ret.type.Assign(type);
+            ret.index.Assign(static_cast<u32>(var));
+            return ret;
+        }
+    }
+    throw NotImplementedException("Variable spilling");
+}
+
+void VarAlloc::Free(Id id) {
+    if (id.is_valid == 0) {
+        // throw LogicError("Freeing invalid variable");
+        return;
+    }
+    auto& use_tracker{GetUseTracker(id.type)};
+    use_tracker.var_use[id.index] = false;
+}
+
+GlslVarType VarAlloc::RegType(IR::Type type) const {
+    switch (type) {
+    case IR::Type::U1:
+        return GlslVarType::U1;
+    case IR::Type::U32:
+        return GlslVarType::U32;
+    case IR::Type::F32:
+        return GlslVarType::F32;
+    case IR::Type::U64:
+        return GlslVarType::U64;
+    case IR::Type::F64:
+        return GlslVarType::F64;
+    default:
+        throw NotImplementedException("IR type {}", type);
+    }
+}
+
+std::string VarAlloc::GetGlslType(GlslVarType type) const {
+    switch (type) {
+    case GlslVarType::U1:
+        return "bool ";
+    case GlslVarType::F16x2:
+        return "f16vec2 ";
+    case GlslVarType::U32:
+        return "uint ";
+    case GlslVarType::S32:
+        return "int ";
+    case GlslVarType::F32:
+        return "float ";
+    case GlslVarType::S64:
+        return "int64_t ";
+    case GlslVarType::U64:
+        return "uint64_t ";
+    case GlslVarType::F64:
+        return "double ";
+    case GlslVarType::U32x2:
+        return "uvec2 ";
+    case GlslVarType::F32x2:
+        return "vec2 ";
+    case GlslVarType::U32x3:
+        return "uvec3 ";
+    case GlslVarType::F32x3:
+        return "vec3 ";
+    case GlslVarType::U32x4:
+        return "uvec4 ";
+    case GlslVarType::F32x4:
+        return "vec4 ";
+    case GlslVarType::Void:
+        return "";
+    default:
+        throw NotImplementedException("Type {}", type);
+    }
+}
+
+VarAlloc::UseTracker& VarAlloc::GetUseTracker(GlslVarType type) {
+    switch (type) {
+    case GlslVarType::U1:
+        return var_bool;
+    case GlslVarType::U32:
+        return var_u32;
+    case GlslVarType::S32:
+        return var_s32;
+    case GlslVarType::F32:
+        return var_f32;
+    case GlslVarType::S64:
+        return var_s64;
+    case GlslVarType::U64:
+        return var_u64;
+    case GlslVarType::F64:
+        return var_f64;
+    case GlslVarType::U32x2:
+        return var_u32x2;
+    case GlslVarType::F32x2:
+        return var_f32x2;
+    case GlslVarType::U32x3:
+        return var_u32x3;
+    case GlslVarType::F32x3:
+        return var_f32x3;
+    case GlslVarType::U32x4:
+        return var_u32x4;
+    case GlslVarType::F32x4:
+        return var_f32x4;
+    default:
+        throw NotImplementedException("Type {}", type);
+    }
+}
+
+const VarAlloc::UseTracker& VarAlloc::GetUseTracker(GlslVarType type) const {
+    switch (type) {
+    case GlslVarType::U1:
+        return var_bool;
+    case GlslVarType::F16x2:
+        return var_f16x2;
+    case GlslVarType::U32:
+        return var_u32;
+    case GlslVarType::S32:
+        return var_s32;
+    case GlslVarType::F32:
+        return var_f32;
+    case GlslVarType::S64:
+        return var_s64;
+    case GlslVarType::U64:
+        return var_u64;
+    case GlslVarType::F64:
+        return var_f64;
+    case GlslVarType::U32x2:
+        return var_u32x2;
+    case GlslVarType::F32x2:
+        return var_f32x2;
+    case GlslVarType::U32x3:
+        return var_u32x3;
+    case GlslVarType::F32x3:
+        return var_f32x3;
+    case GlslVarType::U32x4:
+        return var_u32x4;
+    case GlslVarType::F32x4:
+        return var_f32x4;
+    default:
+        throw NotImplementedException("Type {}", type);
+    }
+}
+
+} // namespace Shader::Backend::GLSL