Re: [PATCH] DWARF support for AIX v3

[David Edelsohn <dje dot gcc at gmail dot com>]

On Tue, Sep 22, 2015 at 4:12 AM, Richard Biener
<richard.guenther@gmail.com> wrote:
> On Mon, Sep 21, 2015 at 5:41 PM, David Edelsohn <dje.gcc@gmail.com> wrote:
>> Appended is a patch to support DWARF on AIX and works with GDB and AIX
>> assembler.  The AIX assembler prepends the CU length to the section
>> and does not want the compiler to provide it, so I need to disable
>> those parts of dwarf2out.c.  I know it's ugly, but, on the upside,
>> this eventually allows GCC to deprecate Stabs, which I think is worth
>> the pain.
>>
>> I discovered that -g3 emits the debug_macros section, which AIX also
>> does not like, so I disable that section as well.  As I mentioned in
>> v2, I moved the calculation of aranges_length to its one use in the
>> output function instead of calculating it early to avoid an unused
>> function argument.
>>
>> I also switched to XCOFF_DEBUGGING_INFO as the macro to test in
>> dwarf2out.c.  I think a target hook or testing that DWARF section
>> names have not been overridden to NULL is overkill. Suggestions
>> welcome, but any solution that disables arbitrary portions of
>> dwarf2out.c is going to be ugly. I doubt that any other system,
>> especially ones based on ELF file format, would ever do this.
>
> Using an existing macro works for me - but as we are working towards
> eliminating conditional compilation can you try using
>
>   if (!XCOFF_DEBUGGING_INFO)
>
> ?  If the macro is not always defined devise a new one defined from
> XCOFF_DEBUGGING_INFO.

You prefer that I define a new macro in defaults.h instead of

#ifndef XCOFF_DEBUGGING_INFO
#define XCOFF_DEBUGGING_INFO 0
#endif

in dwarf2out.c?

- David