Re: [Qemu-devel] [PATCH] pixman: remove -Wredundand-decls

[Markus Armbruster <armbru@redhat.com>]

Alexey Kardashevskiy <aik@ozlabs.ru> writes:

> On 04/16/2013 01:55 AM, Markus Armbruster wrote:
>> Alexey Kardashevskiy <aik@ozlabs.ru> writes:
>>
>>> On 04/15/2013 10:57 PM, Markus Armbruster wrote:
>>>> Alexey Kardashevskiy <aik@ozlabs.ru> writes:
>>>>
>>>>> On 04/15/2013 08:01 PM, Peter Maydell wrote:
>>>>>> On 15 April 2013 10:50, Alexey Kardashevskiy <aik@ozlabs.ru> wrote:
>>>>>>> /home/alexey/pcipassthru/qemu-impreza/../lib4qemu/usr/include/assert.h:67:13:
>>>>>>> error: redundant redeclaration of '__assert_fail'
>>>>>>> [-Werror=redundant-decls]
>>>>>>> /home/alexey/pcipassthru/qemu-impreza/../lib4qemu/usr/include/assert.h:67:13:
>>>>>>> note: previous declaration of '__assert_fail' was here
>>>>>>> /home/alexey/pcipassthru/qemu-impreza/../lib4qemu/usr/include/assert.h:72:13:
>>>>>>> error: redundant redeclaration of '__assert_perror_fail'
>>>>>>> [-Werror=redundant-decls]
>>>>>>
>>>>>> This copy of assert.h seems to be broken. The declarations
>>>>>> should be guarded (by _ASSERT_H_DECLS in my system's copy).
>>>>>
>>>>> Debian? It uses eglibc which is fork (or clone?) of glibc.
>>>>>
>>>>>> If it's widespread we might have to work around this.
>>>>>
>>>>> It is in fedora 18 and glibc's git master branch. Why "if"?
>>>>
>>>> It's in Fedora 17, too, but I *don't* get a warning.  Suspecting your
>>>> compiler.  --version?
>>>
>>>
>>> powerpc64-linux-gcc 4.6.3, 4.7.2, 4.8.0, all the same. I'll try to
>>> track it down tomorrow why it all works when host and target are the
>>> same (pretty sure this is the cse) but I just do not get it... It is
>>> just me who sees obvious error in assert.h which is caused by
>>> -Wno-redundant-decls? Even if you do not hit this now, you will get
>>> there eventually.
>>
>> I don't doubt your gcc+libc is in error.  I just don't want to lose a
>> useful warning because of that.
>>
>> Workaround: configure --disable-werror
>
> This workaround does NOT work if pragmas used. "#pragma GCC diagnostic
> error "-Wredundant-decls"" re-enables warnings as errors.

Bummer.  Could you try the appended patch?

diff --git a/configure b/configure
index 0788e27..41097a2 100755
--- a/configure
+++ b/configure
@@ -3244,8 +3244,10 @@ fi
 
 pragma_disable_unused_but_set=no
 cat > $TMPC << EOF
+#pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wunused-but-set-variable"
 #pragma GCC diagnostic ignored "-Wstrict-prototypes"
+#pragma GCC diagnostic pop
 
 int main(void) {
     return 0;
diff --git a/coroutine-ucontext.c b/coroutine-ucontext.c
index 867a662..4bf2cde 100644
--- a/coroutine-ucontext.c
+++ b/coroutine-ucontext.c
@@ -169,6 +169,7 @@ Coroutine *qemu_coroutine_new(void)
 #ifdef CONFIG_VALGRIND_H
 #ifdef CONFIG_PRAGMA_DIAGNOSTIC_AVAILABLE
 /* Work around an unused variable in the valgrind.h macro... */
+#pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wunused-but-set-variable"
 #endif
 static inline void valgrind_stack_deregister(CoroutineUContext *co)
@@ -176,7 +177,7 @@ static inline void valgrind_stack_deregister(CoroutineUContext *co)
     VALGRIND_STACK_DEREGISTER(co->valgrind_stack_id);
 }
 #ifdef CONFIG_PRAGMA_DIAGNOSTIC_AVAILABLE
-#pragma GCC diagnostic error "-Wunused-but-set-variable"
+#pragma GCC diagnostic pop
 #endif
 #endif
 
diff --git a/include/ui/qemu-pixman.h b/include/ui/qemu-pixman.h
index b032f52..882e2a3 100644
--- a/include/ui/qemu-pixman.h
+++ b/include/ui/qemu-pixman.h
@@ -8,11 +8,12 @@
 
 /* pixman-0.16.0 headers have a redundant declaration */
 #ifdef CONFIG_PRAGMA_DIAGNOSTIC_AVAILABLE
+#pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wredundant-decls"
 #endif
 #include <pixman.h>
 #ifdef CONFIG_PRAGMA_DIAGNOSTIC_AVAILABLE
-#pragma GCC diagnostic error "-Wredundant-decls"
+#pragma GCC diagnostic pop
 #endif
 
 #include "qemu/typedefs.h"
diff --git a/ui/gtk.c b/ui/gtk.c
index 1e105e2..c2c6e38 100644
--- a/ui/gtk.c
+++ b/ui/gtk.c
@@ -38,11 +38,12 @@
 
 #ifdef CONFIG_PRAGMA_DIAGNOSTIC_AVAILABLE
 /* Work around an -Wstrict-prototypes warning in GTK headers */
+#pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wstrict-prototypes"
 #endif
 #include <gtk/gtk.h>
 #ifdef CONFIG_PRAGMA_DIAGNOSTIC_AVAILABLE
-#pragma GCC diagnostic error "-Wstrict-prototypes"
+#pragma GCC diagnostic pop
 #endif