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Re: [PATCH] operand_equal_p checking (PR sanitizer/70683)
- From: Richard Biener <rguenther at suse dot de>
- To: Jakub Jelinek <jakub at redhat dot com>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Wed, 27 Apr 2016 14:41:09 +0200 (CEST)
- Subject: Re: [PATCH] operand_equal_p checking (PR sanitizer/70683)
- Authentication-results: sourceware.org; auth=none
- References: <20160426130238 dot GU26501 at tucnak dot zalov dot cz> <20160426225139 dot GZ26501 at tucnak dot zalov dot cz>
On Wed, 27 Apr 2016, Jakub Jelinek wrote:
> On Tue, Apr 26, 2016 at 03:02:38PM +0200, Jakub Jelinek wrote:
> > The debugging hack is too ugly and slows down the compiler (by artificially
> > increasing number of collisions), so it is not appropriate, but perhaps we
> > can add some internal only use OEP_* flag, pass it to the recursive calls
> > of operand_equal_p and if not set and flag_checking, verify
> > iterative_hash_expr equality in the outermost call).
>
> Here is the corresponding checking patch. It uncovered two further issues
> in the tree.[ch] patch which I'm going to post momentarily.
> Both patches together bootstrapped/regtested on x86_64-linux and i686-linux,
> ok for trunk?
Ok.
Thanks,
Richard.
> 2016-04-27 Jakub Jelinek <jakub@redhat.com>
>
> PR sanitizer/70683
> * tree-core.h (enum operand_equal_flag): Add OEP_NO_HASH_CHECK.
> * fold-const.c (operand_equal_p): If flag_checking and
> OEP_NO_HASH_CHECK is not set in flag, recurse with OEP_NO_HASH_CHECK
> and if it returns non-zero, assert iterative_hash_expr on both
> args is the same.
>
> --- gcc/tree-core.h.jj 2016-04-22 18:21:55.000000000 +0200
> +++ gcc/tree-core.h 2016-04-26 17:47:19.875753297 +0200
> @@ -765,7 +765,9 @@ enum operand_equal_flag {
> OEP_ONLY_CONST = 1,
> OEP_PURE_SAME = 2,
> OEP_MATCH_SIDE_EFFECTS = 4,
> - OEP_ADDRESS_OF = 8
> + OEP_ADDRESS_OF = 8,
> + /* Internal within operand_equal_p: */
> + OEP_NO_HASH_CHECK = 16
> };
>
> /* Enum and arrays used for tree allocation stats.
> --- gcc/fold-const.c.jj 2016-04-22 18:21:32.000000000 +0200
> +++ gcc/fold-const.c 2016-04-26 18:30:40.919080701 +0200
> @@ -2749,6 +2749,25 @@ combine_comparisons (location_t loc,
> int
> operand_equal_p (const_tree arg0, const_tree arg1, unsigned int flags)
> {
> + /* When checking, verify at the outermost operand_equal_p call that
> + if operand_equal_p returns non-zero then ARG0 and ARG1 has the same
> + hash value. */
> + if (flag_checking && !(flags & OEP_NO_HASH_CHECK))
> + {
> + if (operand_equal_p (arg0, arg1, flags | OEP_NO_HASH_CHECK))
> + {
> + inchash::hash hstate0 (0), hstate1 (0);
> + inchash::add_expr (arg0, hstate0, flags);
> + inchash::add_expr (arg1, hstate1, flags);
> + hashval_t h0 = hstate0.end ();
> + hashval_t h1 = hstate1.end ();
> + gcc_assert (h0 == h1);
> + return 1;
> + }
> + else
> + return 0;
> + }
> +
> /* If either is ERROR_MARK, they aren't equal. */
> if (TREE_CODE (arg0) == ERROR_MARK || TREE_CODE (arg1) == ERROR_MARK
> || TREE_TYPE (arg0) == error_mark_node
>
>
> Jakub
>
>
--
Richard Biener <rguenther@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nuernberg)