From 69e73ca7c876c100fad5af1ff6cfe65d3cbea765 Mon Sep 17 00:00:00 2001
From: Atmn Patel <atmnp@nvidia.com>
Date: Wed, 16 Jul 2025 12:46:48 -0700
Subject: [PATCH] [Refactor][NFC] Vendor in BaseCallConv

---
 numba_cuda/numba/cuda/core/callconv.py | 134 +++++++++++++++++++++++++
 numba_cuda/numba/cuda/target.py        |   3 +-
 2 files changed, 136 insertions(+), 1 deletion(-)
 create mode 100644 numba_cuda/numba/cuda/core/callconv.py

diff --git a/numba_cuda/numba/cuda/core/callconv.py b/numba_cuda/numba/cuda/core/callconv.py
new file mode 100644
index 000000000..37ff031fa
--- /dev/null
+++ b/numba_cuda/numba/cuda/core/callconv.py
@@ -0,0 +1,134 @@
+from numba.core import cgutils, types
+
+from llvmlite import ir
+
+int32_t = ir.IntType(32)
+int64_t = ir.IntType(64)
+errcode_t = int32_t
+
+
+def _const_int(code):
+    return ir.Constant(errcode_t, code)
+
+
+RETCODE_OK = _const_int(0)
+RETCODE_EXC = _const_int(-1)
+RETCODE_NONE = _const_int(-2)
+# StopIteration
+RETCODE_STOPIT = _const_int(-3)
+
+FIRST_USEREXC = 1
+
+RETCODE_USEREXC = _const_int(FIRST_USEREXC)
+
+
+class BaseCallConv(object):
+    def __init__(self, context):
+        self.context = context
+
+    def return_optional_value(self, builder, retty, valty, value):
+        if valty == types.none:
+            # Value is none
+            self.return_native_none(builder)
+
+        elif retty == valty:
+            # Value is an optional, need a runtime switch
+            optval = self.context.make_helper(builder, retty, value=value)
+
+            validbit = cgutils.as_bool_bit(builder, optval.valid)
+            with builder.if_then(validbit):
+                retval = self.context.get_return_value(
+                    builder, retty.type, optval.data
+                )
+                self.return_value(builder, retval)
+
+            self.return_native_none(builder)
+
+        elif not isinstance(valty, types.Optional):
+            # Value is not an optional, need a cast
+            if valty != retty.type:
+                value = self.context.cast(
+                    builder, value, fromty=valty, toty=retty.type
+                )
+            retval = self.context.get_return_value(builder, retty.type, value)
+            self.return_value(builder, retval)
+
+        else:
+            raise NotImplementedError(
+                "returning {0} for {1}".format(valty, retty)
+            )
+
+    def return_native_none(self, builder):
+        self._return_errcode_raw(builder, RETCODE_NONE)
+
+    def return_exc(self, builder):
+        self._return_errcode_raw(builder, RETCODE_EXC)
+
+    def return_stop_iteration(self, builder):
+        self._return_errcode_raw(builder, RETCODE_STOPIT)
+
+    def get_return_type(self, ty):
+        """
+        Get the actual type of the return argument for Numba type *ty*.
+        """
+        restype = self.context.data_model_manager[ty].get_return_type()
+        return restype.as_pointer()
+
+    def init_call_helper(self, builder):
+        """
+        Initialize and return a call helper object for the given builder.
+        """
+        ch = self._make_call_helper(builder)
+        builder.__call_helper = ch
+        return ch
+
+    def _get_call_helper(self, builder):
+        return builder.__call_helper
+
+    def unpack_exception(self, builder, pyapi, status):
+        return pyapi.unserialize(status.excinfoptr)
+
+    def raise_error(self, builder, pyapi, status):
+        """
+        Given a non-ok *status*, raise the corresponding Python exception.
+        """
+        bbend = builder.function.append_basic_block()
+
+        with builder.if_then(status.is_user_exc):
+            # Unserialize user exception.
+            # Make sure another error may not interfere.
+            pyapi.err_clear()
+            exc = self.unpack_exception(builder, pyapi, status)
+            with cgutils.if_likely(builder, cgutils.is_not_null(builder, exc)):
+                pyapi.raise_object(exc)  # steals ref
+            builder.branch(bbend)
+
+        with builder.if_then(status.is_stop_iteration):
+            pyapi.err_set_none("PyExc_StopIteration")
+            builder.branch(bbend)
+
+        with builder.if_then(status.is_python_exc):
+            # Error already raised => nothing to do
+            builder.branch(bbend)
+
+        pyapi.err_set_string(
+            "PyExc_SystemError", "unknown error when calling native function"
+        )
+        builder.branch(bbend)
+
+        builder.position_at_end(bbend)
+
+    def decode_arguments(self, builder, argtypes, func):
+        """
+        Get the decoded (unpacked) Python arguments with *argtypes*
+        from LLVM function *func*.  A tuple of LLVM values is returned.
+        """
+        raw_args = self.get_arguments(func)
+        arginfo = self._get_arg_packer(argtypes)
+        return arginfo.from_arguments(builder, raw_args)
+
+    def _get_arg_packer(self, argtypes):
+        """
+        Get an argument packer for the given argument types.
+        """
+        return self.context.get_arg_packer(argtypes)
diff --git a/numba_cuda/numba/cuda/target.py b/numba_cuda/numba/cuda/target.py
index 13d485773..2d4cb2053 100644
--- a/numba_cuda/numba/cuda/target.py
+++ b/numba_cuda/numba/cuda/target.py
@@ -17,7 +17,8 @@
 from numba.core.dispatcher import Dispatcher
 from numba.core.errors import NumbaWarning
 from numba.core.base import BaseContext
-from numba.core.callconv import BaseCallConv, MinimalCallConv
+from numba.core.callconv import MinimalCallConv
+from numba.cuda.core.callconv import BaseCallConv
 from numba.core.typing import cmathdecl
 from numba.core import datamodel