Messages in this thread | | | Subject | Re: [PATCH] gcov: support GCC 7.1 | From | Peter Oberparleiter <> | Date | Mon, 8 May 2017 12:54:13 +0200 |
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I just realized (admittedly somewhat late) that this hasn't been included yet. However this patch is still required for Linux gcov-profiling to build with GCC 7.1.
@Andrew, could you pick this up via your tree?
The original post can be found at https://lkml.org/lkml/2016/11/24/293
On 08.12.2016 13:52, Peter Oberparleiter wrote: > On 24.11.2016 13:46, Martin Liška wrote: >> On 11/09/2016 10:21 AM, Peter Oberparleiter wrote: >>> On 31.10.2016 10:35, Martin Liška wrote: >>>> Starting from GCC 7.1, __gcov_exit is a new symbol expected >>>> to be implemented in a profiling runtime. >>> >>> I tested your patch with kernel 4.9-rc4 compiled with GCC 7.0.0 20161107 >>> (experimental) and validated that it fixes the build error due to a >>> missing __gcov_exit symbol. >>> >>> An attempt to read from one of the .gcda files generated by a kernel >>> compiled this way resulted in a crash though. It appears that the number >>> of GCOV_COUNTERS has changed again for GCC 7.x and must be adjusted in >>> the kernel as well. Could you add that to your patch as well? >> >> Hello. >> >> Sorry, this is fixed in second version of the patch. >> >>> Given that GCC 7.1 has not yet been released, I'm wondering if it is >>> safe to program against interfaces that have not yet been fully >>> finalized. Can you provide an indication on whether these gcov-related >>> aspects of GCC might still be changed until release? >> >> Well, we just flipped to stage3 which means that any new features should >> be added to current master. If you prefer we can commit the patch after >> a release of 7.1 will be done? > > I've given this some more thought: if your patch is not applied, GCOV > kernel profiling will definitely not work with GCC 7.x. If it is > applied, there is a high probability that it will work, and a small > chance that additional patches will be required. Overall I would say > this justifies applying the patch now. > >>> As a side note, please post your patches inline instead of as attachment >>> as that helps quoting them in replies. See also >>> linux/Documentation/SubmittingPatches. >> >> Sure, thanks for info. I'm attaching new version: >> >> Starting from GCC 7.1, __gcov_exit is a new symbol expected >> to be implemented in a profiling runtime. Update number of profile >> counters. >> >> Signed-off-by: Martin Liska <mliska@suse.cz> > > Looks good, thanks! Tested successfully with GCC 7.0.0 20161208 > (experimental) on Linux kernel 4.9-rc8 (compiles successfully and > produces valid kernel .gcda files). > > Andrew, could you pick this change up via your tree? > > Reviewed-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com> > Tested-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com> > >> --- >> kernel/gcov/base.c | 6 ++++++ >> kernel/gcov/gcc_4_7.c | 4 +++- >> 2 files changed, 9 insertions(+), 1 deletion(-) >> >> diff --git a/kernel/gcov/base.c b/kernel/gcov/base.c >> index 2f9df37..85dca5d 100644 >> --- a/kernel/gcov/base.c >> +++ b/kernel/gcov/base.c >> @@ -98,6 +98,12 @@ void __gcov_merge_icall_topn(gcov_type *counters, unsigned int n_counters) >> } >> EXPORT_SYMBOL(__gcov_merge_icall_topn); >> >> +void __gcov_exit (void) >> +{ >> + /* Unused. */ >> +} >> +EXPORT_SYMBOL(__gcov_exit); >> + >> /** >> * gcov_enable_events - enable event reporting through gcov_event() >> * >> diff --git a/kernel/gcov/gcc_4_7.c b/kernel/gcov/gcc_4_7.c >> index 6a5c239..46a18e7 100644 >> --- a/kernel/gcov/gcc_4_7.c >> +++ b/kernel/gcov/gcc_4_7.c >> @@ -18,7 +18,9 @@ >> #include <linux/vmalloc.h> >> #include "gcov.h" >> >> -#if (__GNUC__ > 5) || (__GNUC__ == 5 && __GNUC_MINOR__ >= 1) >> +#if (__GNUC__ >= 7) >> +#define GCOV_COUNTERS 9 >> +#elif (__GNUC__ > 5) || (__GNUC__ == 5 && __GNUC_MINOR__ >= 1) >> #define GCOV_COUNTERS 10 >> #elif __GNUC__ == 4 && __GNUC_MINOR__ >= 9 >> #define GCOV_COUNTERS 9 >>
-- Peter Oberparleiter Linux on z Systems Development - IBM Germany
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