GC buckets in 2.067

[Steven Schveighoffer via Digitalmars-d]

On 12/4/15 7:33 PM, Iain Buclaw via Digitalmars-d wrote:
> On 5 December 2015 at 00:40, Iain Buclaw <ibuclaw at gdcproject.org
> <mailto:ibuclaw at gdcproject.org>> wrote:
>
>     On 4 December 2015 at 21:52, Iain Buclaw <ibuclaw at gdcproject.org
>     <mailto:ibuclaw at gdcproject.org>> wrote:
>
>         On 1 December 2015 at 09:46, Iain Buclaw <ibuclaw at gdcproject.org
>         <mailto:ibuclaw at gdcproject.org>> wrote:
>
>             When running the unittest program for druntime.
>
>             ---
>             Program received signal SIGSEGV, Segmentation fault.
>             __memset_avx2 () at
>             ../sysdeps/x86_64/multiarch/memset-avx2.S:101
>
>             backtrace:
>             #0  __memset_avx2 () at
>             ../sysdeps/x86_64/multiarch/memset-avx2.S:101
>             #1  0x00000000004d45a0 in gc.gc.GC.malloc(ulong, uint,
>             ulong*, const(TypeInfo)) (this=..., size=8, bits=0,
>             alloc_size=0x7fffffffd428, ti=0x714050
>             <TypeInfo_PS2rt3aaA4Impl.init$>) at
>             ../../../../dev/libphobos/libd
>             runtime/gc/gc.d:459
>             #2  0x00000000004c5948 in gc_qalloc (sz=8, ba=0, ti=0x714050
>             <TypeInfo_PS2rt3aaA4Impl.init$>) at
>             ../../../.../dev/libphobos/libdruntime/gc/proxy.d:196
>             #3  0x00000000004450de in core.memory.GC.qalloc(ulong, uint,
>             const(TypeInfo)) (sz=8, ba=0, ti=0x714050
>             <TypeInfo_PS2rt3aaA4Impl.init$>) at
>             ../../../../dev/libphobos/libdruntime/core/memory.d:368
>             #4  0x0000000000420e31 in _d_newitemT (_ti=0x714050
>             <TypeInfo_PS2rt3aaA4Impl.init$>) at
>             ../../../../dev/libphobos/libdruntime/rt/lifetime.d:1096
>             #5  0x0000000000411f6c in _aaGetX (aa=0x7ffff7ed2090,
>             keyti=0x7191a0 <ClassInfo for core.thread.Thread>,
>             valuesize=8, pkey=0x7fffffffd598) at
>             ../../../../dev/libphobos/libdruntime/rt/aaA.d:172
>
>
>         DMD dropped calling this function in favour for _aaGetY().
>
>         Maybe I'm chasing a dead end, but maybe, *maybe* something
>         changed and _aaGetX was not updated parallel?
>
>         Iain.
>
>
>     Well, reverting all of druntime 2.067 (minus the bits that produce
>     new errors) and I don't hit this error.
>
>     At least I have a (rather large) starting point to bisect down. :-)
>
>
> Squashed down to a 1600 line diff of rt.lifetime, everything else has
> been applied and passes the unittests just fine.

I'm interested in hearing what this is. lifetime.d went through a major 
update with struct destructor support in the GC. We've found a couple of 
bugs in there. You should examine the history between 2.067 and now.

-Steve