[Webkit-unassigned] [Bug 28317] Assertion being hit on layout tests in debug build

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=28317





--- Comment #11 from Gavin Barraclough <barraclough at apple.com>  2009-08-20 14:07:36 PDT ---
Bah, sorry, I should have been more explicit - you can get too used to hacking
in JITs.

So, in the dump below the breakpoint instruction you are hitting is at
0x00007f0cfa19f495.

When you hit the breakpoint you should be able to dump the instructions in gdb
using the 'x' command:

(gdb) x/32i 0x00007f0cfa19f495

Should dump 16 instructions at the current pc (substituting whatever your new
pc value is for 0x00007f0cfa19f495).

We're probably really only interested in the first 8 or 9, which should be
similar to those I posted.  We're either looking to see it has planted
different instructions, or possibly the same instructions but the JIT assembler
having used a smaller encoding for an instruction (so the addresses in the
assembly dump are also useful).

cheers,
G.


(In reply to comment #10)
> Thanks Gavin :)
> 
> I did the changes and got the following:
> 
> Program received signal SIGTRAP, Trace/breakpoint trap.
> [Switching to Thread 0x7f0cfa064770 (LWP 10988)]
> 0x00007f0cfa19f495 in ?? ()
> (gdb) bt
> #0  0x00007f0cfa19f495 in ?? ()
> #1  0x00007fffabfe30b0 in ?? ()
> #2  0x00007f0ce14a2740 in ?? ()
> #3  0x00000000012442c0 in ?? ()
> #4  0x00007f0cf9fb0430 in _dl_fixup (l=0x7fffabfe1d60, reloc_arg=<value
> optimized out>) at ../elf/dl-runtime.c:114
> #5  0x00007f0ce0245048 in ?? ()
> #6  0x00007fffabfe23b0 in ?? ()
> #7  0x00007f0cf8d52f90 in JSC::Profiler::s_sharedProfiler () from
> /home/plaes/opt/lib/libwebkit-1.0.so.2
> #8  0x0000000001254750 in ?? ()
> #9  0x0000000001233ca0 in ?? ()
> #10 0x0000000000e88a10 in ?? ()
> #11 0x00007fffabfe30b0 in ?? ()
> #12 0x0000000000000000 in ?? ()
> 
> 
> Any hints on what to look for? :)

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