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Re: [PATCH] operand_equal_p checking (PR sanitizer/70683)
- From: Christophe Lyon <christophe dot lyon at linaro dot org>
- To: Richard Biener <rguenther at suse dot de>
- Cc: Jakub Jelinek <jakub at redhat dot com>, "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>
- Date: Thu, 28 Apr 2016 10:59:08 +0200
- 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> <alpine dot LSU dot 2 dot 11 dot 1604271440550 dot 13384 at t29 dot fhfr dot qr>
Hi,
This caused: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70843
On 27 April 2016 at 14:41, Richard Biener <rguenther@suse.de> wrote:
> 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)