On 10/05/2015 11:56 AM, Segher Boessenkool wrote: > On Mon, Oct 05, 2015 at 11:43:02AM +0200, Florian Weimer wrote: >> On 10/05/2015 11:40 AM, Segher Boessenkool wrote: >>> On Mon, Oct 05, 2015 at 11:20:20AM +0200, Florian Weimer wrote: >>>> On 10/02/2015 09:37 PM, Segher Boessenkool wrote: >>>>> On Fri, Oct 02, 2015 at 01:25:31PM +0200, Florian Weimer wrote: >>>>>> glibc has a preprocessor macro called internal_function which switches >>>>>> to a different calling convention on certain targets (i386 uses stdcall >>>>>> and regparams). For non-K&R function definitions, the compiler enforces >>>>>> that both the prototype declaration and the definition match. >>>>>> >>>>>> When someone writes a patch on a different architecture than i386 and >>>>>> forgets to specify internal_function on both prototype and definition, >>>>>> the build will pass, even though i386 will not compile. >>>>>> >>>>>> Is there a way to use a certain harmless attribute to detect this >>>>>> mismatch even on architectures where internal_function has no effect? >>>>> >>>>> Maybe aligned(1) will do what you want? >>>> >>>> Interesting idea. Would this alter generated code? >>> >>> It shouldn't -- it can only increase alignment (not decrease it). >> >> Why do you think that? > > Because the documentation says so. Maybe it is wrong though, I didn't > test it. If so, please file a bug. I see a difference on x86_64: @@ -3,7 +3,6 @@ .LCOLDB0: .text .LHOTB0: - .p2align 4,,15 .globl f .type f, @function f: I don't think this is a bug because the manual says: “However, when you explicitly specify a function alignment this overrides the effect of the '-falign-functions' […] option for this function.” So I think this attribute isn't useful for this purpose. Looks like we'd need a new attribute, as Jeff suggested. Florian
