From 8be4d04455f70892a94d1e0798e266c948b4750a Mon Sep 17 00:00:00 2001
From: Richard-Qin-X <richard.qin.001@gmail.com>
Date: Fri, 14 Aug 2026 04:33:41 +0800
Subject: [CodeGen] Match LLVM Legalizer ownership

---
 .../rcc/CodeGen/GlobalISel/GISelChangeObserver.h   | 66 ++++++++++++++++++++++
 1 file changed, 66 insertions(+)
 create mode 100644 backend/include/rcc/CodeGen/GlobalISel/GISelChangeObserver.h

(limited to 'backend/include/rcc/CodeGen/GlobalISel/GISelChangeObserver.h')

diff --git a/backend/include/rcc/CodeGen/GlobalISel/GISelChangeObserver.h b/backend/include/rcc/CodeGen/GlobalISel/GISelChangeObserver.h
new file mode 100644
index 0000000..9538f20
--- /dev/null
+++ b/backend/include/rcc/CodeGen/GlobalISel/GISelChangeObserver.h
@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#ifndef RCC_CODEGEN_GLOBALISEL_GISELCHANGEOBSERVER_H
+#define RCC_CODEGEN_GLOBALISEL_GISELCHANGEOBSERVER_H
+
+#include "rcc/CodeGen/MachineFunction.h"
+
+#include <span>
+#include <vector>
+
+namespace rcc {
+
+class MachineInstr;
+
+class GISelChangeObserver {
+public:
+  virtual ~GISelChangeObserver() = default;
+
+  virtual void erasingInstr(MachineInstr &Instruction) = 0;
+  virtual void createdInstr(MachineInstr &Instruction) = 0;
+  virtual void changingInstr(MachineInstr &Instruction) = 0;
+  virtual void changedInstr(MachineInstr &Instruction) = 0;
+};
+
+class GISelObserverWrapper final : public MachineFunction::Delegate,
+                                   public GISelChangeObserver {
+public:
+  GISelObserverWrapper() = default;
+  explicit GISelObserverWrapper(GISelChangeObserver &Observer) {
+    Observers.push_back(&Observer);
+  }
+  explicit GISelObserverWrapper(std::span<GISelChangeObserver *const> InitialObservers)
+      : Observers(InitialObservers.begin(), InitialObservers.end()) {}
+
+  void addObserver(GISelChangeObserver &Observer);
+  void removeObserver(GISelChangeObserver &Observer);
+  void clearObservers() noexcept;
+
+  void erasingInstr(MachineInstr &Instruction) override;
+  void createdInstr(MachineInstr &Instruction) override;
+  void changingInstr(MachineInstr &Instruction) override;
+  void changedInstr(MachineInstr &Instruction) override;
+
+  void handleInsertion(MachineInstr &Instruction) override;
+  void handleRemoval(MachineInstr &Instruction) override;
+
+private:
+  std::vector<GISelChangeObserver *> Observers;
+};
+
+class MachineFunctionDelegateInstaller final {
+public:
+  MachineFunctionDelegateInstaller(MachineFunction &Function,
+                                   MachineFunction::Delegate &Delegate);
+  MachineFunctionDelegateInstaller(const MachineFunctionDelegateInstaller &) = delete;
+  MachineFunctionDelegateInstaller &operator=(const MachineFunctionDelegateInstaller &) = delete;
+  ~MachineFunctionDelegateInstaller();
+
+private:
+  MachineFunction *Function;
+  MachineFunction::Delegate *Delegate;
+};
+
+} // namespace rcc
+
+#endif // RCC_CODEGEN_GLOBALISEL_GISELCHANGEOBSERVER_H
-- 
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