Re: [RFC PATCH 4/4] ui/cocoa: Ignore 'initializer overrides' warnings

[Christian Schoenebeck <qemu_oss@crudebyte.com>]

On Dienstag, 15. Februar 2022 13:06:25 CET Philippe Mathieu-Daudé via wrote:
> We globally ignore the 'initializer overrides' warnings in C code
> since commit c1556a812a ("configure: Disable (clang)
> initializer-overrides warnings"). Unfortunately the ${gcc_flags}
> variable is not propagated to Objective-C flags ($OBJCFLAGS).
> Instead of reworking the configure script to test all supported
> C flags in Objective-C and sanitize them, ignore the warning
> locally with the GCC diagnostic #pragma (Clang ignores it).
> 
> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> ---

What about this instead:

diff --git a/ui/cocoa.m b/ui/cocoa.m
index ac18e14ce0..df9b9be999 100644
--- a/ui/cocoa.m
+++ b/ui/cocoa.m
@@ -652,9 +652,7 @@ QemuCocoaView *cocoaView;
 
     /* translates Macintosh keycodes to QEMU's keysym */
 
-    int without_control_translation[] = {
-        [0 ... 0xff] = 0,   // invalid key
-
+    int without_control_translation[256] = {
         [kVK_UpArrow]       = QEMU_KEY_UP,
         [kVK_DownArrow]     = QEMU_KEY_DOWN,
         [kVK_RightArrow]    = QEMU_KEY_RIGHT,
@@ -667,9 +665,7 @@ QemuCocoaView *cocoaView;
         [kVK_Delete]        = QEMU_KEY_BACKSPACE,
     };
 
-    int with_control_translation[] = {
-        [0 ... 0xff] = 0,   // invalid key
-
+    int with_control_translation[256] = {
         [kVK_UpArrow]       = QEMU_KEY_CTRL_UP,
         [kVK_DownArrow]     = QEMU_KEY_CTRL_DOWN,
         [kVK_RightArrow]    = QEMU_KEY_CTRL_RIGHT,

That warning should only be raised on overlapping designated initializations
which strictly is undefined behaviour. Because which order defines the
precedence of overlapping initializers, is it the order of the designated
intializer list, or rather the memory order?

See also:
https://stackoverflow.com/questions/40920714/is-full-followed-by-partial-initialization-of-a-subobject-undefined-behavior

So I have my doubts whether this warning suppression should be used in QEMU at
all.

Best regards,
Christian Schoenebeck