On 15 August 2017 at 08:56, Diana Picus via cfe-commits < cfe-commits@lists.llvm.org> wrote:
> Ugh, I'm not sure that last email made it through. > > Here's the IR with -Xclang -disable-llvm-passes, at r310400 and r310401: > https://goo.gl/4n84SR > https://goo.gl/gxhxp9 > > The diff between them is small enough so I don't think there's much > point in reducing it further. > Hope that helps. Yes, that helps a lot. The problem was that the implicitly-generated va_list struct for ARM wasn't getting the "CanPassInRegisters" flag set, and got passed indirectly (contrary to the ABI). I've added a test for that kind of problem in r310982, and re-committed the patch as r310983. Thanks for all your assistance here! > On 15 August 2017 at 17:51, Diana Picus <diana.pi...@linaro.org> wrote: > > Actually, I'm not sure I need to reduce it, the diff between the IR > > with -Xclang -no-llvm-passes is pretty small for the version > > with/without the patch. See attached. I hope this helps, it does look > > like a problem with va_arg handling. > > > > Sorry again that this is going so slowly... > > > > On 15 August 2017 at 16:52, Diana Picus <diana.pi...@linaro.org> wrote: > >> On 15 August 2017 at 01:25, Richard Smith <rich...@metafoo.co.uk> > wrote: > >>> On 14 August 2017 at 03:27, Diana Picus via cfe-commits > >>> <cfe-commits@lists.llvm.org> wrote: > >>>> > >>>> Hi, > >>>> > >>>> Strangely enough, it turns out that if I run > >>>> Asan-armhf-with-calls-Noinst-Test on the command line it fails, > >>>> although it doesn't fail when run with lit. > >>> > >>> > >>> Looks like the crash is within the "use_colors == true" portion of > >>> ColoredPrintf, so this would make sense if running the test within lit > turns > >>> off color support (perhaps because the output is not a terminal). > >>> > >> > >> That's a good catch, it seems if I run it with --gtest-color=no it > >> still passes, but prints some garbage at the end: > >> [ PASSED ] 97 tests. > >> YOU HAVE -1094542056 DISABLED F]�뀼��_8�pG����D2 > >> > >> > >>>> > >>>> I've attached the stack > >>>> trace from gdb. It looks like some trouble passing down va_arg > >>>> parameters, but I haven't looked into too much details. The segfault > >>>> happens when we try to do a ldrb r3, [r0, r1], with r1 set to 0 by > >>>> the current function and r0 passed down from the caller. I'm not sure > >>>> if this is the exact same problem as the other tests, but feel free to > >>>> have a look at that code. > >>> > >>> > >>> Have you tried running Asan-armhf-with-calls-Noinst-Test on the > command line > >>> without this patch applied? (It's possible that this is a pre-existing > bug > >>> in ARM varargs call lowering, and is unrelated to the bug we're trying > to > >>> track down. This code path performs an unrelated varargs call between a > >>> va_start / va_end pair, which seems like quite a rare situation, and I > could > >>> easily believe there's something wrong with our lowering that allows > some > >>> portion of the outer va_list state to be clobbered in that scenario.) > >>> > >> > >> It seems to work without the patch. I'm currently trying to reduce > >> Asan-armhf-with-calls-Test and I'll get back to you with the IR or > >> assembly files (whichever makes any difference). > >> > >>>> Meanwhile, I've removed some clutter from Asan-armhf-with-calls-Test > >>>> (which is the original failure that we were seeing) and left only one > >>>> failing test that seemed small enough. I'll try to look at the > >>>> disassembly before/after the patch and maybe even run valgrind on it > >>>> (running it on the original binary naturally takes forever). > >>>> > >>>> Let me know if there's anything else I could try. I can also send you > >>>> disassembly or even LLVM IR for the Asan-armhf-with-calls-Noinst-Test > >>>> if you think it helps. > >>>> > >>>> Cheers, > >>>> Diana > _______________________________________________ > cfe-commits mailing list > cfe-commits@lists.llvm.org > http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits >
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