1 files changed, 64 insertions, 0 deletions
diff --git a/backend/include/rcc/CodeGen/GlobalISel/GISelChangeObserver.h b/backend/include/rcc/CodeGen/GlobalISel/GISelChangeObserver.h
new file mode 100644
index 0000000..cc0c5a0
--- /dev/null
+++ b/backend/include/rcc/CodeGen/GlobalISel/GISelChangeObserver.h
@@ -0,0 +1,64 @@
+// 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