Fix compiler flags related to kernel coverage
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Authored by tuexen on Feb 9 2019, 2:48 PM.

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Reviewers

andrew
emaste
dim

Commits

rS344012: Fix flags used when compiling kern_kcov.c and subr_coverage.c.

Summary

r343746 ensured that the kernel compiles with gcc, but assumes that -fno-sanitize=all implies -fno-sanitize-coverage=trace-pc,trace-cmp, which is not true on clang 7 and gcc 8.2. This patch uses explicit flags and fixes PR 235611.

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rS FreeBSD src repository - subversion

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Event Timeline

tuexen created this revision.Feb 9 2019, 2:48 PM

Herald added a subscriber: imp. · View Herald TranscriptFeb 9 2019, 2:48 PM

Harbormaster completed remote builds in B22412: Diff 53729.Feb 9 2019, 2:48 PM

lwhsu added a subscriber: lwhsu.Feb 9 2019, 4:50 PM

I tested this patch on a kernel build with clang in base and with the amd64-xtoolchain-gcc cross toolchain.

emaste added inline comments.Feb 10 2019, 2:58 PM

sys/conf/kern.mk
28 ↗	(On Diff #53729)	hyphens in the variable name is unusual

Use underscores instead of hyphens as suggested by Ed.

Harbormaster completed remote builds in B22418: Diff 53743.Feb 10 2019, 4:27 PM

tuexen added inline comments.Feb 10 2019, 4:29 PM

sys/conf/kern.mk
28 ↗	(On Diff #53729)	Fixed. I should have figured out that by myself... Thanks for the comment!

andrew added inline comments.Feb 11 2019, 11:10 AM

sys/conf/files
3811 ↗	(On Diff #53743)	This could be written `..."${NORMAL_C:N-fsanitize*}`
sys/conf/kern.mk
28 ↗	(On Diff #53729)	I'm a bit concerned we need to keep these flags in sync in multiple places. I think it would be safer to just filter out the flags we don't want.

tuexen added inline comments.Feb 11 2019, 1:40 PM

sys/conf/files
3811 ↗	(On Diff #53743)	Just using `compile-with "${NORMAL_C:N-fsanitize*}"` does not work. No `-fno-sanitize-coverage...` will be used during make. Do I need to implement something to get this pattern supported?

andrew added inline comments.Feb 11 2019, 1:51 PM

sys/conf/files
3811 ↗	(On Diff #53743)	It should remove any argument from the compile command line that matches the glob. This will therefore remove the `-fsanitize-coverage=...` flag as that will match. It will also remove any other future sanitizers, however I think this will be needed to remove any risk of them recursing into each other.