Still crashes due to aliasing violation (Re: [RFC, PATCH] Split pool_allocator and create a new object_allocator)

[Ulrich Weigand]

On July 17, 2015 6:54:32 PM GMT+02:00, Ulrich Weigand <uweigand@de.ibm.com> wrote:
> >So do we now consider host compilers < 4.3 (4?) unsupported for
> >building
> >mainline GCC, or should we try to work around the issue (e.g. by moving
> >the allocator out-of-line or using some other aliasing barrier)?
> 
> Why is this an issue for stage1 which runs w/o optimization?

Well, this is the SPU compiler on a Cell system, which is technically
a cross compiler from PowerPC (even though the resulting binaries run
natively on the machine).

> For cross compiling we already suggest using known good compilers.

The documentation says:

  To build a cross compiler, we recommend first building and installing
  a native compiler. You can then use the native GCC compiler to build
  the cross compiler. The installed native compiler needs to be GCC
  version 2.95 or later. 

So building with a native GCC 4.1 seems to have been officially
supported until now as far as I can tell (unless you're building Ada).


Now, I could certainly live with a statement that cross compilers can
only be build with a native GCC 4.3 or newer; but that should be IMO
a deliberate decision and be widely announced (maybe even verified
by a configure check?), so that others don't run into the problem;
the nature of its symptoms make the problem difficult to diagnose.


Bye,
Ulrich

-- 
  Dr. Ulrich Weigand
  GNU/Linux compilers and toolchain
  Ulrich.Weigand@de.ibm.com