From 6e8feb15a0d256ca19e88185f78c81f689ce7d34 Mon Sep 17 00:00:00 2001
From: Richard-Qin-X <richard.qin.001@gmail.com>
Date: Fri, 28 Aug 2026 14:07:11 +0800
Subject: [RISCV] Separate calling convention assignment

---
 backend/lib/Target/RISCV/RISCVCallingConv.h | 52 +++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)
 create mode 100644 backend/lib/Target/RISCV/RISCVCallingConv.h

(limited to 'backend/lib/Target/RISCV/RISCVCallingConv.h')

diff --git a/backend/lib/Target/RISCV/RISCVCallingConv.h b/backend/lib/Target/RISCV/RISCVCallingConv.h
new file mode 100644
index 0000000..ba2dcf2
--- /dev/null
+++ b/backend/lib/Target/RISCV/RISCVCallingConv.h
@@ -0,0 +1,52 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#ifndef RCC_LIB_TARGET_RISCV_RISCVCALLINGCONV_H
+#define RCC_LIB_TARGET_RISCV_RISCVCALLINGCONV_H
+
+#include "rcc/CodeGen/TargetCallLowering.h"
+#include "rcc/Target/RISCV/RISCVInstructions.h"
+
+#include <cstddef>
+#include <cstdint>
+#include <span>
+#include <string>
+#include <vector>
+
+namespace rcc::riscv {
+
+struct CallingConventionInfo;
+
+inline constexpr std::uint64_t XLenBytes = 8;
+inline constexpr std::uint64_t ABIStackAlignmentBytes = 16;
+
+[[nodiscard]] constexpr CallingConventionID
+callingConventionID(CallingConvention Convention) noexcept {
+  return CallingConventionID::fromValue(static_cast<std::uint32_t>(Convention));
+}
+
+struct ArgumentAssignmentResult final {
+  std::vector<CCAssignment> Assignments;
+  StackArgumentArea StackArea;
+  std::size_t FirstUnallocatedGPR = 0;
+};
+
+[[nodiscard]] Expected<std::size_t> verifyValueSequence(std::span<const ABIValue> Values,
+                                                        bool RequireRegisters);
+[[nodiscard]] Expected<ArgumentAssignmentResult>
+assignArguments(std::span<const ABIValue> Values, std::size_t FixedArgumentCount, bool IsVariadic,
+                const CallingConventionInfo &Convention);
+[[nodiscard]] Expected<std::vector<CCAssignment>>
+assignReturns(std::span<const ABIValue> Values, bool RequireRegisters,
+              const CallingConventionInfo &Convention);
+[[nodiscard]] bool hasStructReturn(std::span<const ABIValue> Arguments) noexcept;
+[[nodiscard]] Expected<std::string>
+tailCallRejection(const CallLoweringRequest &Request, const ArgumentAssignmentResult &Arguments,
+                  std::span<const CCAssignment> Results,
+                  std::span<const ByValCopyAssignment> ByValCopies,
+                  const CallingConventionInfo &Convention);
+[[nodiscard]] Expected<const CallingConventionInfo *>
+riscvConvention(CallingConventionID Convention);
+
+} // namespace rcc::riscv
+
+#endif // RCC_LIB_TARGET_RISCV_RISCVCALLINGCONV_H
-- 
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