Messages in this thread | | | Subject | Re: [PATCH] bug.h: Work around GCC PR82365 in BUG() | From | Vineet Gupta <> | Date | Tue, 19 Dec 2017 14:38:21 -0800 |
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On 12/19/2017 12:13 PM, Arnd Bergmann wrote: > >> I suppose BUG() implies "dead end" like semantics - which ARC was lacking >> before ? > Correct. Using __builtin_trap() here avoids the 'control reaches end of non-void > function' warnings, but then makes us run into the stack size problem that > I work around with the barrier_before_unreachable(). > > It would be good if you could give this a quick test to see if you get sensible > output from the __builtin_trap();
It does, added a BUG() arbit, hits an abort()
... ISA Extn : atomic ll64 unalign (not used) : mpy[opt 9] div_rem norm barrel-shift swap minmax swape BPU : partial match, cache:2048, Predict Table:16384 BUG: failure at ../arch/arc/mm/tlb.c:827/arc_mmu_init()!
Tested-by: Vineet Gupta <vgupta@synopsys.com>
FWIW newer ARC gcc actually implements the builtin so we get a trap 5 instruction now, vs., abort() calls before.
BTW I missed reading the hunk of your changelog where this addresses the long standing mystery with ARC builds and numerous -Wreturn-type warnings. I always wondered why they were not fixed upstream already, being too lazy to investigate myself, and turns out this was due to this BUG() thingy. phew !
-Vineet
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