[GlobalISel] Split the generic pipeline components

1 files changed, 54 insertions, 0 deletions

diff --git a/backend/include/rcc/CodeGen/GlobalISel/LegalizerInfo.h b/backend/include/rcc/CodeGen/GlobalISel/LegalizerInfo.h
new file mode 100644
index 0000000..218a4c6
--- /dev/null
+++ b/backend/include/rcc/CodeGen/GlobalISel/LegalizerInfo.h
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#ifndef RCC_CODEGEN_GLOBALISEL_LEGALIZERINFO_H
+#define RCC_CODEGEN_GLOBALISEL_LEGALIZERINFO_H
+
+#include "rcc/Support/Error.h"
+
+#include <cstdint>
+
+namespace rcc {
+
+class MachineFunction;
+class MachineInstr;
+class TargetDescription;
+
+enum class LegalizationAction : std::uint8_t {
+  Legal,
+  Unsupported,
+  Custom,
+  Lower,
+  Libcall,
+  WidenScalar,
+  NarrowScalar,
+  MoreElements,
+  FewerElements,
+  Bitcast,
+  ChangeElementType,
+  ChangeAddressSpace,
+};
+
+class LegalizerInfo {
+public:
+  virtual ~LegalizerInfo() = default;
+
+  [[nodiscard]] virtual Expected<LegalizationAction>
+  classify(const MachineInstr &Instruction, const MachineFunction &Function,
+           const TargetDescription &Target) const = 0;
+
+  [[nodiscard]] virtual Expected<void> lower(MachineInstr &Instruction, MachineFunction &Function,
+                                             const TargetDescription &Target,
+                                             LegalizationAction Action) const = 0;
+
+  // This hook performs read-only target checks before a lowering mutation is committed.
+  [[nodiscard]] virtual Expected<void> validateLowering(const MachineInstr &,
+                                                        const MachineFunction &,
+                                                        const TargetDescription &,
+                                                        LegalizationAction) const {
+    return {};
+  }
+};
+
+} // namespace rcc
+
+#endif // RCC_CODEGEN_GLOBALISEL_LEGALIZERINFO_H