1 files changed, 90 insertions, 0 deletions
diff --git a/backend/include/rcc/CodeGen/TargetFrameLowering.h b/backend/include/rcc/CodeGen/TargetFrameLowering.h
new file mode 100644
index 0000000..e3f0f37
--- /dev/null
+++ b/backend/include/rcc/CodeGen/TargetFrameLowering.h
@@ -0,0 +1,90 @@
+// 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;
+};
+
+struct FrameLoweringOptions final {
+  bool EmitDebugOutput = false;
+};
+
+class TargetFrameLowering {
+public:
+  virtual ~TargetFrameLowering() = default;
+
+  [[nodiscard]] virtual PhysicalRegister
+  initialCFARegister(const MachineFunction &Function,
+                     const TargetDescription &Target) const noexcept = 0;
+  [[nodiscard]] virtual std::int64_t initialCFAOffset(const MachineFunction &) const noexcept {
+    return 0;
+  }
+
+  [[nodiscard]] virtual Expected<void> prepareFrame(MachineFunction &Function,
+                                                    const TargetDescription &Target,
+                                                    FrameLoweringOptions Options = {}) 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 isCalleeSavedRegister(PhysicalRegister, const MachineFunction &,
+                                                   const TargetDescription &) const noexcept {
+    return false;
+  }
+
+  [[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