From 578bb3b45bd3b9f6a714facdfb0ac289b3657f82 Mon Sep 17 00:00:00 2001
From: Simone <simococo03@gmail.com>
Date: Thu, 28 Dec 2023 15:11:12 +0100
Subject: [PATCH] better representation (inspired by fleroviux's Lunatic)

---
 src/backend/core/JIT/IR/Opcode.hpp   | 42 ++++++++++++
 src/backend/core/JIT/IR/Register.hpp | 11 ++++
 src/backend/core/JIT/IR/Value.hpp    | 98 ++++++++++++++++++++++++++++
 3 files changed, 151 insertions(+)
 create mode 100644 src/backend/core/JIT/IR/Opcode.hpp
 create mode 100644 src/backend/core/JIT/IR/Register.hpp
 create mode 100644 src/backend/core/JIT/IR/Value.hpp

diff --git a/src/backend/core/JIT/IR/Opcode.hpp b/src/backend/core/JIT/IR/Opcode.hpp
new file mode 100644
index 00000000..12ffd354
--- /dev/null
+++ b/src/backend/core/JIT/IR/Opcode.hpp
@@ -0,0 +1,42 @@
+#pragma once
+#include <log.hpp>
+
+namespace n64 {
+enum class IROpcodeClass {
+  Normal, Special, Regimm, COP0, COP1
+};
+
+struct IROpcode {
+  virtual ~IROpcode() = default;
+  virtual auto GetClass() const -> IROpcodeClass = 0;
+  virtual auto Reads (IRVariable const& var) -> bool = 0;
+  virtual auto Writes(IRVariable const& var) -> bool = 0;
+  virtual void Repoint(IRVariable const& var_old, IRVariable const& var_new) = 0;
+  virtual void PropagateConstant(IRVariable const& var, IRConstant const& constant) {}
+};
+
+template<IROpcodeClass _class>
+struct IROpcodeBase : IROpcode {
+  auto GetClass() const -> IROpcodeClass override { return _class; }
+};
+
+struct IRNoOp final : IROpcodeBase<IROpcodeClass::NOP> {
+  auto Reads(IRVariable const& var) -> bool override {
+    return false;
+  }
+
+  auto Writes(IRVariable const& var) -> bool override {
+    return false;
+  }
+
+  void Repoint(
+    IRVariable const& var_old,
+    IRVariable const& var_new
+  ) override {
+  }
+
+  auto ToString() -> std::string override {
+    return "nop";
+  }
+};
+}
\ No newline at end of file
diff --git a/src/backend/core/JIT/IR/Register.hpp b/src/backend/core/JIT/IR/Register.hpp
new file mode 100644
index 00000000..e42adccb
--- /dev/null
+++ b/src/backend/core/JIT/IR/Register.hpp
@@ -0,0 +1,11 @@
+#pragma once
+#include <log.hpp>
+
+namespace n64 {
+struct IRGuestReg {
+  IRGuestReg(u8 reg) : reg(reg) {}
+
+  /// The ARM general purpose register
+  const u8 reg;
+};
+}
\ No newline at end of file
diff --git a/src/backend/core/JIT/IR/Value.hpp b/src/backend/core/JIT/IR/Value.hpp
new file mode 100644
index 00000000..94b853bd
--- /dev/null
+++ b/src/backend/core/JIT/IR/Value.hpp
@@ -0,0 +1,98 @@
+#pragma once
+#include <log.hpp>
+
+namespace n64 {
+enum IRPrimitive {
+  Uint32, Sint32, Uint64, Sint32, Uint128, Sint128
+};
+
+struct IRVariable {
+  IRVariable(IRPrimitive type, const u32 id, char const* const label) : type(type), id(id), label(label) {}
+private:
+  IRPrimitive type;
+  const u32 id;
+  char const* const label;
+};
+
+struct IRConstant {
+  IRConstant() {}
+  IRConstant(IRPrimitive type, u128 value) : type(type), value(value) {}
+private:
+  IRPrimitive type = Uint128;
+  u128 value = 0;
+};
+
+struct IRAnyRef {
+  IRAnyRef() {}
+  IRAnyRef(IRVariable const& variable) : type(Type::Variable), var(&variable) {}
+  IRAnyRef(IRConstant const& constant) : type(Type::Constant), constant(constant) {}
+
+  auto operator=(IRAnyRef const& other) -> IRAnyRef& {
+    type = other.type;
+    if (IsConstant()) {
+      constant = other.constant;
+    } else {
+      var = other.var;
+    }
+    return *this;
+  }
+
+  bool IsNull() const { return type == Type::Null; }
+  bool IsVariable() const { return type == Type::Variable; }
+  bool IsConstant() const { return type == Type::Constant; }
+
+  auto GetVar() const -> IRVariable const& {
+    if (!IsVariable()) {
+      Util::panic("called GetVar() but value is a constant or null");
+    }
+    return *var;
+  }
+
+  auto GetConst() const -> IRConstant const& {
+    if (!IsConstant()) {
+      Util::panic("called GetConst() but value is a variable or null");
+    }
+    return constant;
+  }
+
+  void Repoint(IRVariable const& var_old, IRVariable const& var_new) {
+    if (IsVariable() && (&GetVar() == &var_old)) {
+      var = &var_new;
+    }
+  }
+
+  void PropagateConstant(IRVariable const& var, IRConstant const& constant) {
+    if (IsVariable() && (&GetVar() == &var)) {
+      type = Type::Constant;
+      this->constant = constant;
+    }
+  }
+private:
+  enum Type {
+    Null, Variable, Constant
+  };
+
+  Type type;
+
+  union {
+    IRVariable const* var;
+    IRConstant constant;
+  };
+};
+
+struct IRVarRef {
+  IRVarRef(IRVariable const& var) : p_var(&var) {}
+
+  auto Get() const -> IRVariable const& {
+    return *p_var;
+  }
+
+  void Repoint(IRVariable const& var_old, IRVariable const& var_new) {
+    if (&var_old == p_var) {
+      p_var = &var_new;
+    }
+  }
+private:
+  IRVariable const* p_var;
+};
+}
\ No newline at end of file