illumos gate

Yeah, you need to use builtin_offsetof for this.

You'll also need to fix the use in Xen to be actually constant, and you'll need to fix the fact we have a billion different places that define their own offsetof

This doesn't look like a "bug", more likely a "feature". Please provide patches to fix it.

The hard part about fixing it properly, is dealing with the fact we have way way too many offsetof definitions.

The second hard part is the macros in some of the Xen code I mentioned above.

I have chunks of code for this (and the similar problems I imagine Igor will run in to next), I just have a bunch of other stuff to fix for the sake of a newer GCC before polishing the illumos branch.

Maybe test for GCC version as well:

--- uts.orig/usr/src/uts/common/sys/sysmacros.h    2012-10-08 00:26:00.000000000 +0000
+++ uts/usr/src/uts/common/sys/sysmacros.h    2012-11-18 20:23:08.087883575 +0000
@@ -370,7 +370,11 @@
 #if defined(_KERNEL) && !defined(_KMEMUSER)

 #if !defined(offsetof)
-#define    offsetof(s, m)    ((size_t)(&(((s *)0)->m)))
+# if defined(__GNUC__)
+#  define    offsetof(s, m)    __builtin_offsetof(s, m)
+# else
+#  define    offsetof(s, m)    ((size_t)(&(((s *)0)->m)))
+# endif /* __GNUC__ */
 #endif /* !offsetof */

 #define    container_of(m, s, name)            \\

have to update file too:
usr/src/head/iso/stddef_iso.h

Igor Kozhukhov wrote:

have to update file too:
usr/src/head/iso/stddef_iso.h

GCC uses its own stddef.h

GCC does not use it's own stddef.h while building illumos.

Also, as I said, a whole lot of things we compile don't use that offsetof.

Those patches look correct to me (presuming include order is correct, some things are fussy about sysmacros.h).

I should mention that wsdiff is going to be noisy, because you're going to be influencing whether some files get the function or macro versions of major() and minor(), but when I'd checked previously that would have no affect on behaviour.

Thanks,

i did review a long time with it:
http://cr.dilos.org/cr/igork/il-3373/
but it was discarded as always