On 5/22/19 3:13 AM, Martin Liška wrote: > On 5/21/19 1:51 PM, Richard Biener wrote: >> On Tue, May 21, 2019 at 1:02 PM Martin Liška <mli...@suse.cz> wrote: >>> >>> On 5/21/19 11:38 AM, Richard Biener wrote: >>>> On Tue, May 21, 2019 at 12:07 AM Jeff Law <l...@redhat.com> wrote: >>>>> >>>>> On 5/13/19 1:41 AM, Martin Liška wrote: >>>>>> On 11/8/18 9:56 AM, Martin Liška wrote: >>>>>>> On 11/7/18 11:23 PM, Jeff Law wrote: >>>>>>>> On 10/30/18 6:28 AM, Martin Liška wrote: >>>>>>>>> On 10/30/18 11:03 AM, Jakub Jelinek wrote: >>>>>>>>>> On Mon, Oct 29, 2018 at 04:14:21PM +0100, Martin Liška wrote: >>>>>>>>>>> +hashtab_chk_error () >>>>>>>>>>> +{ >>>>>>>>>>> + fprintf (stderr, "hash table checking failed: " >>>>>>>>>>> + "equal operator returns true for a pair " >>>>>>>>>>> + "of values with a different hash value"); >>>>>>>>>> BTW, either use internal_error here, or at least if using fprintf >>>>>>>>>> terminate with \n, in your recent mail I saw: >>>>>>>>>> ...different hash valueduring RTL pass: vartrack >>>>>>>>>> ^^^^^^ >>>>>>>>> Sure, fixed in attached patch. >>>>>>>>> >>>>>>>>> Martin >>>>>>>>> >>>>>>>>>>> + gcc_unreachable (); >>>>>>>>>>> +} >>>>>>>>>> Jakub >>>>>>>>>> >>>>>>>>> 0001-Sanitize-equals-and-hash-functions-in-hash-tables.patch >>>>>>>>> >>>>>>>>> From 0d9c979c845580a98767b83c099053d36eb49bb9 Mon Sep 17 00:00:00 2001 >>>>>>>>> From: marxin <mli...@suse.cz> >>>>>>>>> Date: Mon, 29 Oct 2018 09:38:21 +0100 >>>>>>>>> Subject: [PATCH] Sanitize equals and hash functions in hash-tables. >>>>>>>>> >>>>>>>>> --- >>>>>>>>> gcc/hash-table.h | 40 +++++++++++++++++++++++++++++++++++++++- >>>>>>>>> 1 file changed, 39 insertions(+), 1 deletion(-) >>>>>>>>> >>>>>>>>> diff --git a/gcc/hash-table.h b/gcc/hash-table.h >>>>>>>>> index bd83345c7b8..694eedfc4be 100644 >>>>>>>>> --- a/gcc/hash-table.h >>>>>>>>> +++ b/gcc/hash-table.h >>>>>>>>> @@ -503,6 +503,7 @@ private: >>>>>>>>> >>>>>>>>> value_type *alloc_entries (size_t n CXX_MEM_STAT_INFO) const; >>>>>>>>> value_type *find_empty_slot_for_expand (hashval_t); >>>>>>>>> + void verify (const compare_type &comparable, hashval_t hash); >>>>>>>>> bool too_empty_p (unsigned int); >>>>>>>>> void expand (); >>>>>>>>> static bool is_deleted (value_type &v) >>>>>>>>> @@ -882,8 +883,12 @@ hash_table<Descriptor, Allocator> >>>>>>>>> if (insert == INSERT && m_size * 3 <= m_n_elements * 4) >>>>>>>>> expand (); >>>>>>>>> >>>>>>>>> - m_searches++; >>>>>>>>> +#if ENABLE_EXTRA_CHECKING >>>>>>>>> + if (insert == INSERT) >>>>>>>>> + verify (comparable, hash); >>>>>>>>> +#endif >>>>>>>>> >>>>>>>>> + m_searches++; >>>>>>>>> value_type *first_deleted_slot = NULL; >>>>>>>>> hashval_t index = hash_table_mod1 (hash, m_size_prime_index); >>>>>>>>> hashval_t hash2 = hash_table_mod2 (hash, m_size_prime_index); >>>>>>>>> @@ -930,6 +935,39 @@ hash_table<Descriptor, Allocator> >>>>>>>>> return &m_entries[index]; >>>>>>>>> } >>>>>>>>> >>>>>>>>> +#if ENABLE_EXTRA_CHECKING >>>>>>>>> + >>>>>>>>> +/* Report a hash table checking error. */ >>>>>>>>> + >>>>>>>>> +ATTRIBUTE_NORETURN ATTRIBUTE_COLD >>>>>>>>> +static void >>>>>>>>> +hashtab_chk_error () >>>>>>>>> +{ >>>>>>>>> + fprintf (stderr, "hash table checking failed: " >>>>>>>>> + "equal operator returns true for a pair " >>>>>>>>> + "of values with a different hash value\n"); >>>>>>>>> + gcc_unreachable (); >>>>>>>>> +} >>>>>>>> I think an internal_error here is probably still better than a simple >>>>>>>> fprintf, even if the fprintf is terminated with a \n :-) >>>>>>> Fully agree with that, but I see a lot of build errors when using >>>>>>> internal_error. >>>>>>> >>>>>>>> The question then becomes can we bootstrap with this stuff enabled and >>>>>>>> if not, are we likely to soon? It'd be a shame to put it into >>>>>>>> EXTRA_CHECKING, but then not be able to really use EXTRA_CHECKING >>>>>>>> because we've got too many bugs to fix. >>>>>>> Unfortunately it's blocked with these 2 PRs: >>>>>>> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87845 >>>>>>> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87847 >>>>>> Hi. >>>>>> >>>>>> I've just added one more PR: >>>>>> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90450 >>>>>> >>>>>> I'm sending updated version of the patch that provides a disablement for >>>>>> the 3 PRs >>>>>> with a new function disable_sanitize_eq_and_hash. >>>>>> >>>>>> With that I can bootstrap and finish tests. However, I've done that with >>>>>> a patch >>>>>> limits maximal number of checks: >>>>> So rather than call the disable_sanitize_eq_and_hash, can you have its >>>>> state set up when you instantiate the object? It's not a huge deal, >>>>> just thinking about loud. >>>>> >>>>> >>>>> >>>>> So how do we want to go forward, particularly the EXTRA_EXTRA checking >>>>> issue :-) >>>> >>>> There is at least one PR where we have a table where elements _in_ the >>>> table are never compared against each other but always against another >>>> object (I guess that's usual even), but the setup is in a way that the >>>> comparison function only works with those. With the patch we verify >>>> hashing/comparison for something that is never used. >>>> >>>> So - wouldn't it be more "correct" to only verify comparison/hashing >>>> at lookup time, using the object from the lookup and verify that against >>>> all other elements? >>> >>> I don't a have problem with that. Apparently this changes fixes >>> PR90450 and PR87847. >>> >>> Changes from previous version: >>> - verification happens only when an element is searched (not inserted) >>> - new argument 'sanitize_eq_and_hash' added for hash_table::hash_table >>> - new param has been introduced hash-table-verification-limit in order >>> to limit number of elements that are compared within a table >>> - verification happens only with flag_checking >= 2 >>> >>> I've been bootstrapping and testing the patch right now. >> >> Looks like I misremembered the original patch. The issue isn't >> comparing random two elements in the table. >> >> That it fixes PR90450 is because LIM never calls find_slot_with_hash >> without INSERTing. >> > > There's updated version of the patch where I check all find operations > (both w/ and w/o insertion). > > Patch can bootstrap on x86_64-linux-gnu and survives regression tests > except for: > > $ ./xgcc -B. > /home/marxin/Programming/gcc/gcc/testsuite/gcc.dg/torture/pr63941.c -O2 -c > hash table checking failed: equal operator returns true for a pair of values > with a different hash value > during GIMPLE pass: lim > /home/marxin/Programming/gcc/gcc/testsuite/gcc.dg/torture/pr63941.c: In > function ‘fn1’: > /home/marxin/Programming/gcc/gcc/testsuite/gcc.dg/torture/pr63941.c:6:1: > internal compiler error: in hashtab_chk_error, at hash-table.h:1019 > 6 | fn1 () > | ^~~ > 0x6c5725 hashtab_chk_error > /home/marxin/Programming/gcc/gcc/hash-table.h:1019 > 0xe504ea hash_table<mem_ref_hasher, false, xcallocator>::verify(ao_ref* > const&, unsigned int) > /home/marxin/Programming/gcc/gcc/hash-table.h:1040 > 0xe504ea hash_table<mem_ref_hasher, false, > xcallocator>::find_slot_with_hash(ao_ref* const&, unsigned int, insert_option) > /home/marxin/Programming/gcc/gcc/hash-table.h:960 > 0xe504ea gather_mem_refs_stmt > /home/marxin/Programming/gcc/gcc/tree-ssa-loop-im.c:1501 > 0xe504ea analyze_memory_references > /home/marxin/Programming/gcc/gcc/tree-ssa-loop-im.c:1625 > 0xe504ea tree_ssa_lim > /home/marxin/Programming/gcc/gcc/tree-ssa-loop-im.c:2646 > 0xe504ea execute > /home/marxin/Programming/gcc/gcc/tree-ssa-loop-im.c:2708 > > Richi: it's after your recent patch. > > For some reason I don't see PR87847 issue any longer. > > > May I install the patch with disabled sanitization in tree-ssa-loop-im.c ? Don't we still need to deal with the naked fprintf when there's a failure. ie, shouldn't we be raising it with a gcc_assert or somesuch?
jeff