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[PATCH] operand_equal_p checking (PR sanitizer/70683)
- From: Jakub Jelinek <jakub at redhat dot com>
- To: Richard Biener <rguenther at suse dot de>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Wed, 27 Apr 2016 00:51:39 +0200
- Subject: [PATCH] operand_equal_p checking (PR sanitizer/70683)
- Authentication-results: sourceware.org; auth=none
- References: <20160426130238 dot GU26501 at tucnak dot zalov dot cz>
- Reply-to: Jakub Jelinek <jakub at redhat dot com>
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?
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