[patch] Fix unaligned access in function returning composite type

[Eric Botcazou]

Hi,

In Ada, we support all sorts of data structure layout, including on strict-
alignment targets, and the compiler must generate glue code if necessary.
The problem here is a function returning a structure by invisible reference
into a field which is not sufficient aligned because the enclosing object is
packed: in this case, the caller passes an address that is not correctly
aligned to the callee, which can result in an unaligned access in the callee.

Tested on x86_64-suse-linux and SPARC/Solaris, OK for the mainline.


2014-10-06 Eric Botcazou <***@adacore.com>

* calls.c (expand_call): Do not use the target as the return slot if
it is not sufficiently aligned.


2014-10-06 Eric Botcazou <***@adacore.com>

* gnat.dg/return4.adb: New test.
* gnat.dg/return4_pkg.ad[sb]: New helper.

[Richard Biener]

Post by Eric Botcazou
Hi,
In Ada, we support all sorts of data structure layout, including on strict-
alignment targets, and the compiler must generate glue code if necessary.
The problem here is a function returning a structure by invisible reference
into a field which is not sufficient aligned because the enclosing object is
packed: in this case, the caller passes an address that is not correctly
aligned to the callee, which can result in an unaligned access in the callee.
Tested on x86_64-suse-linux and SPARC/Solaris, OK for the mainline.

Ok.

Thanks,
Richard.

Post by Eric Botcazou
* calls.c (expand_call): Do not use the target as the return slot if
it is not sufficiently aligned.
* gnat.dg/return4.adb: New test.
* gnat.dg/return4_pkg.ad[sb]: New helper.
--
Eric Botcazou