Re: disable objective-c stuff when theres no objective-c cu.

[Jan Kratochvil <jan.kratochvil@redhat.com>]

On Wed, 06 Oct 2010 15:12:06 +0200, Matt Rice wrote:
> what I mean is that 'break' is not related to the current language,
> but the language which we want to be the current language
> when the breakpoint is hit.  and so 'set language' to use language
> specific breakpoints is arguably wrong because the current language
> may not be the language of the breakpoint we want set.

OK, I understand that Obj-C is special that it (a) is mixed with C/C++ and
even possibly having C/C++ main(), (b) requiring Obj-C specific support to
just figure out where to place a breakpoint.

That `objc:' breakpoint prefix etc. could be nice but a more conservative
change IMO also makes sense.  I can imagine it could be inconvenient for Obj-C
development (which I do not know myself, though).


> doesn't seem as though reading language symfiles frobs the current
> language afaict.

It really does not.


+  set_language_has_cu_loaded(subfile->language);

here should be a space: `...loaded (subfile->...'


+/* A mask for languages that want to enable specific behaviours if (not when)
+   a compilation unit of that language has been loaded. */
+#define CU_LOADED_C_LANG_MASK		0x1 << 0
+#define CU_LOADED_CPLUS_LANG_MASK	0x1 << 1

Do I miss something why don't you use enum language like (1 << language_objc)?
nr_languages == 14 so it fits fine into a bitmask.  BTW such #define right
hand sides should be in parentheses (for operator priority surprises during
their use).


+static unsigned int cu_languages_loaded_mask;

One can imagine this mask may (possibly in the future) modify user-visible
behavior due to a different code paths being executed due to it - which is
also its purpose.

Loading program A, kill, loading program B would behave differently than just
loading program B with fresh GDB.

I would place such mask into `struct objfile'.  Checking its content then
means iterating ALL_OBJFILES but I would find it acceptable.  (Some
accelerations of such scheme are also possible - when performance is a goal of
this patch anyway.)  This would make the GDB behavior more deterministic IMO.


+unsigned int
+language_has_cu_loaded (enum language lang)
+{
+  unsigned int lang_mask = mask_for_language (lang);
+  return cu_languages_loaded_mask & lang_mask;
+}

As it returns boolean it should be just `int' and I would make it normalized
to 0-or-1.


Thanks,
Jan