[Python-Dev] HEADS UP: Compilation risk with new GCC 4.5.0

[Jesus Cea]

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On 12/05/10 15:39, James Y Knight wrote:
> While assuming the stack is 16byte aligned is undeniably an
> ABI-violation in GCC, at this point, it's surely simpler to just go
> along: the new unofficial ABI for x86 is that the stack must always be
> left in 16-byte alignment...

You can not rule out other software embedding python inside, or
callbacks from foreign code. For instance, Berkeley DB library can do
callbacks to Python code.

> So, just change psyco to always use 16-byte-aligned stackframes. GCC has
> used 16byte-aligned stackframes for a heck of a long time now (so if the
> stack starts 16byte aligned on entry to a function it will stay that way
> on calls). So usually the only way people run into unaligned stacks is
> via hand-written assembly code or JIT compilers.

Not all the universe is GCC based. For instance, Solaris system
libraries are not compiled using GCC. The world is bigger that Linux/GCC.

> I think you'll be a lot happier just modifying Psyco than making
> everyone else in the world change their compiler flags.

Would be nice if GCC 4.5.1 would solve this :). They are objectivelly
breaking the x86 ABI.

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