Re: [PATCH] Fix ICE with bogus posix_memalign call (PR middle-end/67222)

[Richard Biener <richard dot guenther at gmail dot com>]

On Mon, Aug 17, 2015 at 8:01 PM, Marek Polacek <polacek@redhat.com> wrote:
> Here we were crashing on an invalid call to posix_memalign.  The code in
> lower_builtin_posix_memalign assumed that the call had valid arguments.
> The reason the C FE doesn't reject this code is, in short, that
> int <T> () is compatible with int <T> (void **, size_t, size_t) and we
> use the former -- so convert_arguments doesn't complain.
>
> So I think let's validate the arguments in lower_stmt.  I decided to
> give an error if we see an invalid usage of posix_memalign, since
> other code (e.g. alias machinery) assumes correct arguments as well.
>
> Bootstrapped/regtested on x86_64-linux, ok for trunk?

I don't think you can give errors here.  Note that the "appropriate"
way to do the check is to simply use

if (gimple_builtin_call_types_compatible_p (stmt, decl))

not lowering in case it's not compatible is ok.

Thanks,
Richard.

> 2015-08-17  Marek Polacek  <polacek@redhat.com>
>
>         PR middle-end/67222
>         * gimple-low.c: Include "builtins.h".
>         (lower_stmt): Validate arguments of posix_memalign.
>
>         * gcc.dg/torture/pr67222.c: New test.
>
> diff --git gcc/gimple-low.c gcc/gimple-low.c
> index d4697e2..03194f0 100644
> --- gcc/gimple-low.c
> +++ gcc/gimple-low.c
> @@ -39,6 +39,7 @@ along with GCC; see the file COPYING3.  If not see
>  #include "langhooks.h"
>  #include "gimple-low.h"
>  #include "tree-nested.h"
> +#include "builtins.h"
>
>  /* The differences between High GIMPLE and Low GIMPLE are the
>     following:
> @@ -345,10 +346,22 @@ lower_stmt (gimple_stmt_iterator *gsi, struct lower_data *data)
>                 data->cannot_fallthru = false;
>                 return;
>               }
> -           else if (DECL_FUNCTION_CODE (decl) == BUILT_IN_POSIX_MEMALIGN
> -                    && flag_tree_bit_ccp)
> +           else if (DECL_FUNCTION_CODE (decl) == BUILT_IN_POSIX_MEMALIGN)
>               {
> -               lower_builtin_posix_memalign (gsi);
> +               if (gimple_call_num_args (stmt) != 3
> +                   || !validate_gimple_arglist (dyn_cast <gcall *> (stmt),
> +                                                POINTER_TYPE, INTEGER_TYPE,
> +                                                INTEGER_TYPE, VOID_TYPE))
> +                 {
> +                   error_at (gimple_location (stmt), "invalid arguments "
> +                             "to %qD", decl);
> +                   gsi_next (gsi);
> +                   return;
> +                 }
> +               if (flag_tree_bit_ccp)
> +                 lower_builtin_posix_memalign (gsi);
> +               else
> +                 gsi_next (gsi);
>                 return;
>               }
>           }
> diff --git gcc/testsuite/gcc.dg/torture/pr67222.c gcc/testsuite/gcc.dg/torture/pr67222.c
> index e69de29..cf39aa1 100644
> --- gcc/testsuite/gcc.dg/torture/pr67222.c
> +++ gcc/testsuite/gcc.dg/torture/pr67222.c
> @@ -0,0 +1,19 @@
> +/* { dg-do compile } */
> +/* { dg-options "-Wno-implicit-function-declaration" } */
> +
> +void
> +foo (void **p)
> +{
> +  posix_memalign (); /* { dg-error "invalid arguments" } */
> +  posix_memalign (p); /* { dg-error "invalid arguments" } */
> +  posix_memalign (0); /* { dg-error "invalid arguments" } */
> +  posix_memalign (p, 1); /* { dg-error "invalid arguments" } */
> +  posix_memalign (p, "foo"); /* { dg-error "invalid arguments" } */
> +  posix_memalign ("gnu", "gcc"); /* { dg-error "invalid arguments" } */
> +  posix_memalign (1, p); /* { dg-error "invalid arguments" } */
> +  posix_memalign (1, 2); /* { dg-error "invalid arguments" } */
> +  posix_memalign (1, 2, 3); /* { dg-error "invalid arguments" } */
> +  posix_memalign (p, p, p); /* { dg-error "invalid arguments" } */
> +  posix_memalign (p, "qui", 3); /* { dg-error "invalid arguments" } */
> +  posix_memalign (p, 1, 2);
> +}
>
>         Marek