> > On Jul 8, 2015, at 4:37 PM, Adrian Chadd <adrian.ch...@gmail.com> wrote: > > On 8 July 2015 at 15:34, Warner Losh <i...@bsdimp.com> wrote: >> I doubt it would ever be useful. >> For gcc, just test for 4.2.1. >> For clang, what specific feature do you need to test for? >> >> Do you have a specific use case in mind? >> >> This strikes me as a really bad idea absent some use case that has a real >> example behind it. > > Well, vendors have in the past shipped modified compilers for systems > they're doing bring-up on. So if there are differences between the > in-tree compiler for a given clang version and the vendor supplied > modified one, I'd like to know. > > I know it's going to be a while until another CPU family with a > not-yet-upstream compiler comes out..
I’m having trouble understanding when this would be generally useful. If we have a situation where the exact same clang version as we have in the tree is also the version of the compiler a vendor released and there’s some substantial difference between the two such that you need conditional code to make it work on both, that might be one scenario. But such a scenario hasn’t come up in the past very often, and generally it has been resolved with an ifdef __arch__ sort of thing because the in-tree compiler didn’t support that CPU well enough to use, while the out of tree one did. Warner > -a > >> Warner >> >>> On Jul 8, 2015, at 4:28 PM, Adrian Chadd <adrian.ch...@gmail.com> wrote: >>> >>> hi, >>> >>> ok. would it be possible to add a blessed way to say "this is the >>> freebsd modified compiler in-tree" ? >>> >>> I'd like to see / play around with more external-toolchain driven >>> building and using it for port bringups. >>> >>> Thanks, >>> >>> >>> -adrian >>> >>> >>> On 8 July 2015 at 15:22, Pedro Giffuni <p...@freebsd.org> wrote: >>>> >>>> >>>> On 07/08/15 17:04, Adrian Chadd wrote: >>>>> >>>>> Is there a blessed way to see whether the compiler we're using is an >>>>> external compiler, or an internal one? >>>> >>>> >>>> No blessed way: you still have to determine the version of >>>> the external compiler for most purposes anyways. >>>> The internal compiler (even clang) always reports itself >>>> as gcc 4.2. >>>> >>>>> eg, the version check isn't enough - it's just a number. how do I know >>>>> if it's freebsd clang versus upstream clang? >>>>> (Or in my instance, freebsd-gcc versus upstream-gcc.) >>>> >>>> >>>> If the compiler reports itself as gcc >= 4.3 it is surely an >>>> external compiler. The tricky part is that our internal gcc >>>> supports some gcc 4.3 flags and Apple extensions >>>> (blocks), but those are not causing a problem AFAICT. >>>> >>>> Pedro. >>>> >>>> >>>>> >>>>> -a >>>>> >>>>> >>>>> On 8 July 2015 at 14:09, Pedro Giffuni <p...@freebsd.org> wrote: >>>>>> >>>>>> >>>>>> On 07/08/15 13:36, Luigi Rizzo wrote: >>>>>>> >>>>>>> Author: luigi >>>>>>> Date: Wed Jul 8 18:36:37 2015 >>>>>>> New Revision: 285284 >>>>>>> URL: https://svnweb.freebsd.org/changeset/base/285284 >>>>>>> >>>>>>> Log: >>>>>>> only enable immintrin when clang is used. The base gcc does not >>>>>>> support >>>>>>> it. >>>>>>> Reviewed by: delphij >>>>>>> >>>>>>> Modified: >>>>>>> head/lib/liblzma/config.h >>>>>>> >>>>>>> Modified: head/lib/liblzma/config.h >>>>>>> >>>>>>> >>>>>>> ============================================================================== >>>>>>> --- head/lib/liblzma/config.h Wed Jul 8 18:12:24 2015 >>>>>>> (r285283) >>>>>>> +++ head/lib/liblzma/config.h Wed Jul 8 18:36:37 2015 >>>>>>> (r285284) >>>>>>> @@ -150,7 +150,8 @@ >>>>>>> #define HAVE_ICONV 1 >>>>>>> /* Define to 1 if you have the <immintrin.h> header file. */ >>>>>>> -#if defined(__FreeBSD__) && defined(__amd64__) >>>>>>> +/* FreeBSD - only with clang because the base gcc does not support it >>>>>>> */ >>>>>>> +#if defined(__clang__) && defined(__FreeBSD__) && defined(__amd64__) >>>>>>> #define HAVE_IMMINTRIN_H 1 >>>>>>> #endif >>>>>>> >>>>>> FWIW, gcc 4.3+ does have it so this may some undesired (but hidden) >>>>>> effect when building with an external gcc. >>>>>> >>>>>> Pedro. >>>>>> >>>> >>> >>
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