[committed][gdb/build] Handle deprecation of scm_install_gmp_memory_functions

[Tom de Vries <tdevries@suse.de>]

On 7/7/22 09:58, Tom de Vries wrote:
> Hi,
> 
> When building gdb with guile 3.0.8, we run into:
> ...
> gdb/guile/guile.c: In function \
>    'void gdbscm_initialize(const extension_language_defn*)':
> gdb/guile/guile.c:680:5: error: 'scm_install_gmp_memory_functions' is \
>    deprecated [-Werror=deprecated-declarations]
>    680 |     scm_install_gmp_memory_functions = 0;
>        |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> In file included from /usr/include/guile/3.0/libguile.h:128,
>                   from gdb/guile/guile-internal.h:30,
>                   from gdb/guile/guile.c:36:
> /usr/include/guile/3.0/libguile/deprecated.h:164:20: note: declared here
>    164 | SCM_DEPRECATED int scm_install_gmp_memory_functions;
>        |                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> cc1plus: all warnings being treated as errors
> make[1]: *** [Makefile:1896: guile/guile.o] Error 1
> ...
> 
> The variable has been deprecated because it no longer has any effect.
> 
> Fix this by disabling the specific deprecation warning.
> 
> Also handle upcoming guile versions > 3.0, in which the variable will be
> removed, by limiting the usage of the variable to guile versions <= 3.0.
> 
> This does not break anything.  The variable was merely used to address a
> problem present in guile versions <= v3.0.5.
> 
> Note that we don't limit the usage of the variable to guile versions <= 3.0.5,
> because we want to support f.i. building against 3.0.6 and then using a shared
> lib with 3.0.5.
> 
> Tested on x86_64-linux.
> 
> Co-Authored-By: Tom de Vries <tdevries@suse.de>
> 
> Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=28994
> 
> Any comments?
> 

Committed.

Thanks,
- Tom

> [gdb/build] Handle deprecation of scm_install_gmp_memory_functions
> 
> ---
>   gdb/guile/guile.c | 10 ++++++++++
>   1 file changed, 10 insertions(+)
> 
> diff --git a/gdb/guile/guile.c b/gdb/guile/guile.c
> index 14b191ded62..e5565b627d9 100644
> --- a/gdb/guile/guile.c
> +++ b/gdb/guile/guile.c
> @@ -677,7 +677,17 @@ gdbscm_initialize (const struct extension_language_defn *extlang)
>          "double free or corruption (out)" error.
>          Work around the libguile bug by disabling the installation of the
>          libgmp memory functions by guile initialization.  */
> +
> +    /* The scm_install_gmp_memory_functions variable should be removed after
> +       version 3.0, so limit usage to 3.0 and before.  */
> +#if SCM_MAJOR_VERSION < 3 || (SCM_MAJOR_VERSION == 3 && SCM_MINOR_VERSION == 0)
> +    /* This variable is deprecated in Guile 3.0.8 and later but remains
> +       available in the whole 3.0 series.  */
> +#pragma GCC diagnostic push
> +#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
>       scm_install_gmp_memory_functions = 0;
> +#pragma GCC diagnostic pop
> +#endif
>   
>       /* scm_with_guile is the most portable way to initialize Guile.  Plus
>          we need to initialize the Guile support while in Guile mode (e.g.,