Re: [PATCH] Fix for call feature having nine parameters or more in AIX

[Ulrich Weigand via Gdb-patches <gdb-patches@sourceware.org>]

Aditya Kamath1 <Aditya.Kamath1@ibm.com> wrote:

>-                 space += ((len - argbytes + 3) & -4);
>+                space += ((len - argbytes + (int) pow (2, (int)log2 (wordsize)) -1) & -wordsize);

This seems unnecessarily complex, as wordsize is always a power of 2.
It could simply be: 
+                 space += ((len - argbytes + wordsize - 1) & -wordsize);

>If not let me know what else I can learn or need to change.

I think this is still not quite correct.  Depending on the type,
some parameters that are not integers (e.g. structs) should not
be extended, as that doesn't make sense for this type.  When
loading into registers, you see the existing code:

          memset (word, 0, reg_size);
          if (type->code () == TYPE_CODE_INT
             || type->code () == TYPE_CODE_ENUM
             || type->code () == TYPE_CODE_BOOL
             || type->code () == TYPE_CODE_CHAR)
            /* Sign or zero extend the "int" into a "word".  */
            store_unsigned_integer (word, reg_size, byte_order,
                                    unpack_long (type, arg->contents ().data ()));
          else
            memcpy (word, arg->contents ().data (), len);

It would probably be best to duplicate that logic for the
stack argument case.

Also, the "argbytes" case seems wrong - this is the case where
an argument fits "half" in registers and "half" on the stack.
In those cases, it does not make any sense to "extend" just
the second half on its own ...

Bye,
Ulrich