For the Renesas Super-H processor, gdb provides these
set sh calling-convention convention
Set the calling-convention used when calling functions from gdb.
Allowed values are ‘gcc’, which is the default setting, and ‘renesas’.
With the ‘gcc’ setting, functions are called using the gcc calling
convention. If the DWARF-2 information of the called function specifies
that the function follows the Renesas calling convention, the function
is called using the Renesas calling convention. If the calling convention
is set to ‘renesas’, the Renesas calling convention is always used,
regardless of the DWARF-2 information. This can be used to override the
default of ‘gcc’ if debug information is missing, or the compiler
does not emit the DWARF-2 calling convention entry for a function.