Re: [PATCH] Fix AIX build break.

[Tom Tromey <tom@tromey.com>]

> The only thing I am unsure of is the utils.c file where we also use
> the deprecated_warning_hook. Should we use an object of
> warning_hook_class there as well?

I'll add some notes inline.  I don't think this patch can really work.
 
> From the experiments I conducted this is true. It is because
> g_complaint_interceptor is a static thread_local variable and not used
> anywhere else we do not see it as an unreferenced symbol in AIX.

Don't be deceived by the 'static' keyword.  C++ overloads this.  This
variable is in fact extern.

> +static thread_local void (*deprecated_warning_hook) (const char *, va_list);

This is defined in two places.  This is confusing at best, but the one
here (in complaints.c) means that warning_hook_class won't interoperate
properly with the other global.  This seems very weird.

> +warning_hook_class::warning_hook_class (warning_hook_handler new_handler)

I wouldn't put '_class' in a class name.
It's more normal in gdb to prefix scoped things with "scoped_", but
other choices are possible.

> diff --git a/gdb/utils.c b/gdb/utils.c
> index b326033e9ff..23530c2a41f 100644
> --- a/gdb/utils.c
> +++ b/gdb/utils.c
> @@ -82,6 +82,8 @@
>  #include "pager.h"
>  #include "run-on-main-thread.h"
 
> +static thread_local void (*deprecated_warning_hook) (const char *, va_list);
> +
 
This is static in utils.c now, so it means that nothing else can affect it.
However this changes how the interception works -- it disables it.  But,
the reason the interception is done is to avoid emitting warnings from
worker threads.

Tom