Messages in this thread | | | From | Michael Ellerman <> | Subject | Re: [PATCH] compiler: Don't perform compiletime_assert with -O0. | Date | Thu, 31 Aug 2017 12:16:53 +1000 |
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Joe Stringer <joe@ovn.org> writes:
> On 30 August 2017 at 15:59, Andrew Morton <akpm@linux-foundation.org> wrote: >> On Tue, 29 Aug 2017 16:01:14 -0700 Joe Stringer <joe@ovn.org> wrote: >> >>> Recent changes[0] to make use of __compiletime_assert() from >>> container_of() increased the usage of this macro, allowing developers to >>> notice type conflicts in usage of container_of() at compile time. >>> However, the implementation of __compiletime_assert relies on compiler >>> optimizations to report an error. This means that if a developer uses >>> "-O0" with any code that performs container_of(), the compiler will >>> always report an error regardless of whether there is an actual problem >>> in the code. >>> >>> This patch disables compile_time_assert when optimizations are disabled >>> to allow such code to compile with CFLAGS="-O0". >> >> I'm wondering if we should backport this into -stable. Probably not, >> as I doubt if many people use -O0 - it's a pretty weird thing to do. I >> used to use it a bit because it makes the ".lst" files (intermingled .c >> and .s files) make more sense. In fact I'm wondering how you even >> noticed this? > > Local debugging, was trying to get a better understanding of the > underlying assembly and the code I was using just happened to use > container_of().
Does the kernel actually build with -O0? I didn't think it actually worked.
cheers
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