[CodeGen] Add explicit MachineFunction cloning

Deep-clone the live MachineIR graph with deterministic identity maps while rebuilding CFG, def-use, ties, register configuration, and memory operand ownership. Verify both source and destination and omit detached arena history.

1 files changed, 49 insertions, 0 deletions

diff --git a/backend/include/rcc/CodeGen/MachineFunctionCloner.h b/backend/include/rcc/CodeGen/MachineFunctionCloner.h
new file mode 100644
index 0000000..3abdf78
--- /dev/null
+++ b/backend/include/rcc/CodeGen/MachineFunctionCloner.h
@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#ifndef RCC_CODEGEN_MACHINEFUNCTIONCLONER_H
+#define RCC_CODEGEN_MACHINEFUNCTIONCLONER_H
+
+#include "rcc/CodeGen/MachineIRTypes.h"
+#include "rcc/CodeGen/Register.h"
+#include "rcc/CodeGen/StableID.h"
+#include "rcc/Support/Error.h"
+
+#include <memory>
+#include <optional>
+#include <string>
+#include <unordered_map>
+
+namespace rcc {
+
+class InstructionSet;
+class MachineFunction;
+
+struct MachineFunctionCloneOptions final {
+  MachineFunctionStableID NewStableID;
+  std::optional<std::string> NewName;
+};
+
+struct MachineFunctionCloneResult final {
+  MachineFunctionCloneResult();
+  MachineFunctionCloneResult(const MachineFunctionCloneResult &) = delete;
+  MachineFunctionCloneResult &operator=(const MachineFunctionCloneResult &) = delete;
+  MachineFunctionCloneResult(MachineFunctionCloneResult &&) noexcept;
+  MachineFunctionCloneResult &operator=(MachineFunctionCloneResult &&) noexcept;
+  ~MachineFunctionCloneResult();
+
+  std::unique_ptr<MachineFunction> ClonedFunction;
+  std::unordered_map<MachineBlockStableID, MachineBlockStableID> BlockStableIDs;
+  std::unordered_map<MachineInstrStableID, MachineInstrStableID> InstructionStableIDs;
+  std::unordered_map<Register, Register> VirtualRegisters;
+  std::unordered_map<FrameIndex, FrameIndex> FrameIndices;
+  std::unordered_map<ConstantPoolIndex, ConstantPoolIndex> ConstantPoolIndices;
+  std::unordered_map<JumpTableIndex, JumpTableIndex> JumpTableIndices;
+};
+
+[[nodiscard]] Expected<MachineFunctionCloneResult>
+cloneMachineFunction(const MachineFunction &Source, const InstructionSet &Instructions,
+                     MachineFunctionCloneOptions Options);
+
+} // namespace rcc
+
+#endif // RCC_CODEGEN_MACHINEFUNCTIONCLONER_H