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

Tom de Vries via Gdb-patches
2022-07-07T07:58:43Z

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?

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.,