glasm: Add GLASM backend infrastructure

src/shader_recompiler/backend/glasm/reg_alloc.h

@@ -0,0 +1,46 @@
+// Copyright 2021 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <bitset>
+
+#include "common/common_types.h"
+
+namespace Shader::IR {
+class Inst;
+class Value;
+} // namespace Shader::IR
+
+namespace Shader::Backend::GLASM {
+
+struct Id {
+    u32 base_element : 2;
+    u32 num_elements_minus_one : 2;
+    u32 index : 26;
+    u32 is_spill : 1;
+    u32 is_condition_code : 1;
+};
+
+class RegAlloc {
+public:
+    std::string Define(IR::Inst& inst, u32 num_elements = 1, u32 alignment = 1);
+
+    std::string Consume(const IR::Value& value);
+
+private:
+    static constexpr size_t NUM_REGS = 4096;
+    static constexpr size_t NUM_ELEMENTS = 4;
+
+    std::string Consume(IR::Inst& inst);
+
+    Id Alloc(u32 num_elements, u32 alignment);
+
+    void Free(Id id);
+
+    size_t num_used_registers{};
+    std::bitset<NUM_REGS> register_use{};
+};
+
+} // namespace Shader::Backend::GLASM