This is the mail archive of the gcc-patches@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [PATCH, PR 57748] Check for out of bounds access, Part 2


On Tue, Sep 24, 2013 at 4:52 AM, Bernd Edlinger
<bernd.edlinger@hotmail.de> wrote:
> Hi,
>
> with the attached patch the read-side of the out of bounds accesses are fixed.
> There is a single new test case pr57748-3.c that is derived from Martin's test case.
> The test case does only test the read access and does not depend on part 1 of the
> patch.
>
> This patch was boot-strapped and regression tested on x86_64-unknown-linux-gnu.
>
> Additionally I generated eCos and an eCos-application (on ARMv5 using packed
> structures) with an arm-eabi cross compiler, and looked for differences in the
> disassembled code with and without this patch, but there were none.
>
> OK for trunk?

Index: gcc/expr.c
===================================================================
--- gcc/expr.c  (revision 202778)
+++ gcc/expr.c  (working copy)
@@ -9878,7 +9878,7 @@
                          && modifier != EXPAND_STACK_PARM
                          ? target : NULL_RTX),
                         VOIDmode,
-                        modifier == EXPAND_SUM ? EXPAND_NORMAL : modifier);
+                        EXPAND_MEMORY);

        /* If the bitfield is volatile, we want to access it in the
           field's mode, not the computed mode.

context suggests that we may arrive with EXPAND_STACK_PARM here
which is a correctness modifier (see its docs).  But I'm not too familiar
with the details of the various expand modifiers, Eric may be though.

That said, I still believe that fixing the misalign path in expand_assignment
would be better than trying to avoid it.  For this testcase the issue is
again that expand_assignment passes the wrong mode/target to the
movmisalign optab.

Richard.

>
> Regards
> Bernd.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]