From da8bc76b4bf7d1a7b025d6c8ef5809551467dcc7 Mon Sep 17 00:00:00 2001
From: Richard-Qin-X <richard.qin.001@gmail.com>
Date: Sun, 9 Aug 2026 13:23:48 +0800
Subject: [CodeGen] Implement RV64GC frame lowering

---
 backend/include/rcc/CodeGen/TargetFrameLowering.h | 73 +++++++++++++++++++++++
 1 file changed, 73 insertions(+)
 create mode 100644 backend/include/rcc/CodeGen/TargetFrameLowering.h

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

diff --git a/backend/include/rcc/CodeGen/TargetFrameLowering.h b/backend/include/rcc/CodeGen/TargetFrameLowering.h
new file mode 100644
index 0000000..1712616
--- /dev/null
+++ b/backend/include/rcc/CodeGen/TargetFrameLowering.h
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#ifndef RCC_CODEGEN_TARGETFRAMELOWERING_H
+#define RCC_CODEGEN_TARGETFRAMELOWERING_H
+
+#include "rcc/CodeGen/MachineIRTypes.h"
+#include "rcc/CodeGen/Register.h"
+#include "rcc/Support/Error.h"
+
+#include <cstddef>
+#include <cstdint>
+
+namespace rcc {
+
+class MachineBasicBlock;
+class MachineFunction;
+class MachineInstr;
+class RegisterScavenger;
+class TargetDescription;
+
+struct FrameIndexReference final {
+  PhysicalRegister BaseRegister;
+  std::int64_t Offset = 0;
+};
+
+class TargetFrameLowering {
+public:
+  virtual ~TargetFrameLowering() = default;
+
+  [[nodiscard]] virtual Expected<void> prepareFrame(MachineFunction &Function,
+                                                    const TargetDescription &Target) const = 0;
+  [[nodiscard]] virtual Expected<void>
+  insertCalleeSavedSpillsAndRestores(MachineFunction &Function,
+                                     const TargetDescription &Target) const = 0;
+  [[nodiscard]] virtual Expected<void>
+  processFunctionBeforeFrameFinalized(MachineFunction &, const TargetDescription &) const {
+    return {};
+  }
+  [[nodiscard]] virtual Expected<void> finalizeFrame(MachineFunction &Function,
+                                                     const TargetDescription &Target) const = 0;
+
+  [[nodiscard]] virtual bool isCallFramePseudo(const MachineInstr &Instruction) const noexcept = 0;
+  [[nodiscard]] virtual Expected<void>
+  eliminateCallFramePseudo(MachineInstr &Instruction, MachineFunction &Function,
+                           const TargetDescription &Target, RegisterScavenger &Scavenger) const = 0;
+
+  [[nodiscard]] virtual Expected<void> emitPrologue(MachineFunction &Function,
+                                                    const TargetDescription &Target,
+                                                    RegisterScavenger &Scavenger) const = 0;
+  [[nodiscard]] virtual bool
+  isEpilogueTerminator(const MachineInstr &Instruction,
+                       const TargetDescription &Target) const noexcept = 0;
+  [[nodiscard]] virtual Expected<void>
+  emitEpilogue(MachineBasicBlock &Block, MachineInstr &Terminator, MachineFunction &Function,
+               const TargetDescription &Target, RegisterScavenger &Scavenger) const = 0;
+  [[nodiscard]] virtual Expected<void>
+  processFunctionBeforeFrameIndexElimination(MachineFunction &, const TargetDescription &) const {
+    return {};
+  }
+
+  [[nodiscard]] virtual Expected<FrameIndexReference>
+  getFrameIndexReference(const MachineFunction &Function, const MachineInstr &Instruction,
+                         FrameIndex Index, std::int64_t OperandOffset) const = 0;
+  [[nodiscard]] virtual Expected<void> eliminateFrameIndex(MachineInstr &Instruction,
+                                                           std::size_t OperandIndex,
+                                                           MachineFunction &Function,
+                                                           const TargetDescription &Target,
+                                                           RegisterScavenger &Scavenger) const = 0;
+};
+
+} // namespace rcc
+
+#endif // RCC_CODEGEN_TARGETFRAMELOWERING_H
-- 
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