Hi!
On 2021-09-01T19:31:19-0600, Martin Sebor via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
> On 8/30/21 4:46 AM, Thomas Schwinge wrote:
>> Ping -- we still need to plug the memory leak; see patch attached, and/or
>> long discussion here:
>
> Thanks for answering my questions. I have no concerns with going
> forward with the patch as is.
Thanks, Martin. Ping for formal approval (and review for using proper
C++ terminology in the 'gcc/hash-table.h:hash_table::expand' source code
comment that I'm adding). Patch again attached, for easy reference.
> Just a suggestion/request: unless
> this patch fixes all the outstanding problems you know of or suspect
> in this area (leaks/missing dtor calls) and unless you plan to work
> on those in the near future, please open a bug for them with a brain
> dump of what you learned. That should save us time when the day
> comes to tackle those.
ACK. I'm not aware of any additional known problems. (In our email
discussion, we did have some "vague ideas" for opportunities of
clarification/clean-up, but these aren't worth filing PRs for; needs
someone to gain understanding, taking a look.)
Grüße
Thomas
>> On 2021-08-16T14:10:00-0600, Martin Sebor <mse...@gmail.com> wrote:
>>> On 8/16/21 6:44 AM, Thomas Schwinge wrote:
>>>> On 2021-08-12T17:15:44-0600, Martin Sebor via Gcc <g...@gcc.gnu.org> wrote:
>>>>> On 8/6/21 10:57 AM, Thomas Schwinge wrote:
>>>>>> So I'm trying to do some C++... ;-)
>>>>>>
>>>>>> Given:
>>>>>>
>>>>>> /* A map from SSA names or var decls to record fields. */
>>>>>> typedef hash_map<tree, tree> field_map_t;
>>>>>>
>>>>>> /* For each propagation record type, this is a map from SSA names
>>>>>> or var decls
>>>>>> to propagate, to the field in the record type that should be
>>>>>> used for
>>>>>> transmission and reception. */
>>>>>> typedef hash_map<tree, field_map_t> record_field_map_t;
>>>>>>
>>>>>> Thus, that's a 'hash_map<tree, hash_map<tree, tree>>'. (I may do that,
>>>>>> right?) Looking through GCC implementation files, very most of all uses
>>>>>> of 'hash_map' boil down to pointer key ('tree', for example) and
>>>>>> pointer/integer value.
>>>>>
>>>>> Right. Because most GCC containers rely exclusively on GCC's own
>>>>> uses for testing, if your use case is novel in some way, chances
>>>>> are it might not work as intended in all circumstances.
>>>>>
>>>>> I've wrestled with hash_map a number of times. A use case that's
>>>>> close to yours (i.e., a non-trivial value type) is in cp/parser.c:
>>>>> see class_to_loc_map_t.
>>>>
>>>> Indeed, at the time you sent this email, I already had started looking
>>>> into that one! (The Fortran test cases that I originally analyzed, which
>>>> triggered other cases of non-POD/non-trivial destructor, all didn't
>>>> result in a memory leak, because the non-trivial constructor doesn't
>>>> actually allocate any resources dynamically -- that's indeed different in
>>>> this case here.) ..., and indeed:
>>>>
>>>>> (I don't remember if I tested it for leaks
>>>>> though. It's used to implement -Wmismatched-tags so compiling
>>>>> a few tests under Valgrind should show if it does leak.)
>>>>
>>>> ... it does leak memory at present. :-| (See attached commit log for
>>>> details for one example.)
>>
>> (Attached "Fix 'hash_table::expand' to destruct stale Value objects"
>> again.)
>>
>>>> To that effect, to document the current behavior, I propose to
>>>> "Add more self-tests for 'hash_map' with Value type with non-trivial
>>>> constructor/destructor"
>>
>> (We've done that in commit e4f16e9f357a38ec702fb69a0ffab9d292a6af9b
>> "Add more self-tests for 'hash_map' with Value type with non-trivial
>> constructor/destructor", quickly followed by bug fix
>> commit bb04a03c6f9bacc890118b9e12b657503093c2f8
>> "Make 'gcc/hash-map-tests.c:test_map_of_type_with_ctor_and_dtor_expand'
>> work on 32-bit architectures [PR101959]".
>>
>>>> (Also cherry-pick into release branches, eventually?)
>>
>>>>>> Then:
>>>>>>
>>>>>> record_field_map_t field_map ([...]); // see below
>>>>>> for ([...])
>>>>>> {
>>>>>> tree record_type = [...];
>>>>>> [...]
>>>>>> bool existed;
>>>>>> field_map_t &fields
>>>>>> = field_map.get_or_insert (record_type, &existed);
>>>>>> gcc_checking_assert (!existed);
>>>>>> [...]
>>>>>> for ([...])
>>>>>> fields.put ([...], [...]);
>>>>>> [...]
>>>>>> }
>>>>>> [stuff that looks up elements from 'field_map']
>>>>>> field_map.empty ();
>>>>>>
>>>>>> This generally works.
>>>>>>
>>>>>> If I instantiate 'record_field_map_t field_map (40);', Valgrind is happy.
>>>>>> If however I instantiate 'record_field_map_t field_map (13);' (where '13'
>>>>>> would be the default for 'hash_map'), Valgrind complains:
>>>>>>
>>>>>> 2,080 bytes in 10 blocks are definitely lost in loss record 828
>>>>>> of 876
>>>>>> at 0x483DD99: calloc (vg_replace_malloc.c:762)
>>>>>> by 0x175F010: xcalloc (xmalloc.c:162)
>>>>>> by 0xAF4A2C: hash_table<hash_map<tree_node*, tree_node*,
>>>>>> simple_hashmap_traits<default_hash_traits<tree_node*>, tree_node*>
>>>>>> >::hash_entry, false, xcallocator>::hash_table(unsigned long, bool,
>>>>>> bool, bool, mem_alloc_origin) (hash-table.h:275)
>>>>>> by 0x15E0120: hash_map<tree_node*, tree_node*,
>>>>>> simple_hashmap_traits<default_hash_traits<tree_node*>, tree_node*>
>>>>>> >::hash_map(unsigned long, bool, bool, bool) (hash-map.h:143)
>>>>>> by 0x15DEE87: hash_map<tree_node*, hash_map<tree_node*,
>>>>>> tree_node*, simple_hashmap_traits<default_hash_traits<tree_node*>,
>>>>>> tree_node*> >, simple_hashmap_traits<default_hash_traits<tree_node*>,
>>>>>> hash_map<tree_node*, tree_node*,
>>>>>> simple_hashmap_traits<default_hash_traits<tree_node*>, tree_node*> > >
>>>>>> >::get_or_insert(tree_node* const&, bool*) (hash-map.h:205)
>>>>>> by 0x15DD52C: execute_omp_oacc_neuter_broadcast()
>>>>>> (omp-oacc-neuter-broadcast.cc:1371)
>>>>>> [...]
>>>>>>
>>>>>> (That's with '#pragma GCC optimize "O0"' at the top of the 'gcc/*.cc'
>>>>>> file.)
>>>>>>
>>>>>> My suspicion was that it is due to the 'field_map' getting resized as it
>>>>>> incrementally grows (and '40' being big enough for that to never happen),
>>>>>> and somehow the non-POD (?) value objects not being properly handled
>>>>>> during that. Working my way a bit through 'gcc/hash-map.*' and
>>>>>> 'gcc/hash-table.*' (but not claiming that I understand all that, off
>>>>>> hand), it seems as if my theory is right: I'm able to plug this memory
>>>>>> leak as follows:
>>>>>>
>>>>>> --- gcc/hash-table.h
>>>>>> +++ gcc/hash-table.h
>>>>>> @@ -820,6 +820,8 @@ hash_table<Descriptor, Lazy,
>>>>>> Allocator>::expand ()
>>>>>> {
>>>>>> value_type *q = find_empty_slot_for_expand
>>>>>> (Descriptor::hash (x));
>>>>>> new ((void*) q) value_type (std::move (x));
>>>>>> + //BAD Descriptor::remove (x); // (doesn't make sense and) a
>>>>>> ton of "Invalid read [...] inside a block of size [...] free'd"
>>>>>> + x.~value_type (); //GOOD This seems to work! -- but does
>>>>>> it make sense?
>>>>>> }
>>>>>>
>>>>>> p++;
>>>>>>
>>>>>> However, that doesn't exactly look like a correct fix, does it? I'd
>>>>>> expect such a manual destructor call in combination with placement new
>>>>>> (that is being used here, obviously) -- but this is after 'std::move'?
>>>>>> However, this also survives a smoke-test-like run of parts of the GCC
>>>>>> testsuite, bootstrap and complete run now ongoing.
>>>>>
>>>>> If explicitly calling the dtor on the moved object is the right thing
>>>>> to do I'd expect to see such invocations elsewhere in hash_table but
>>>>> I don't. It does seem like removed elements ought to be destroyed,
>>>>> but it also seems like the destruction should go through some traits
>>>>> class (e.g., call Descriptor::remove and mark_deleted or do some
>>>>> similar dance), and be called from other member functions that move
>>>>> elements.
>>>>
>>>> So, we shall assume that any "real C++" use case (that is, C++ class) is
>>>> using the appropriate C++ method, that is, 'typed_delete_remove', which
>>>> does 'delete', which does destroy the C++ object, if applicable, else
>>>> 'typed_noop_remove'.
>>>>
>>>> (Shall we look into the few places that use 'typed_free_remove' via
>>>> 'free_ptr_hash', and potentially replace them with 'typed_delete_remove'?
>>>> Or is there a reason for the two schemes to co-exist, other than for
>>>> legacy reasons? Anyway, that's for another day.)
>>>
>>> I find all these these traits pretty much impenetrable.
>>
>> (Indeed. ... which triggered this reflex with me, to try simplifying
>> this by getting rid of 'typed_free_remove' etc...)
>>
>>> I guess
>>> intuitively, I'd expect Descriptor::remove() to destroy an element,
>>> but I have no idea if that would be right given the design.
>>
>> So 'typed_delete_remove' does destruct via 'delete'. 'typed_free_remove'
>> doesn't -- but is only used via 'free_ptr_hash', where this isn't
>> relevant? 'typed_noop_remove' I haven't considered yet regarding that
>> issue. Anyway, that's all for another day.
>>
>>>> What is different in the 'hash_table::expand' case is that all the Value
>>>> objects do get 'std::move'd into a new blob of memory via placement new
>>>> (so a subsequent 'delete' via 'typed_delete_remove' is not appropriate),
>>>> but then the stale Value objects never get destructed. And indeed an
>>>> explicit destructor call (which, as I understand is a no-op for primitive
>>>> types; "pseudo destructor") is the right thing to do; see
>>>> <https://stackoverflow.com/questions/6730403/how-to-delete-object-constructed-via-placement-new-operator>
>>>> and others, for example. (Therefore, I don't think this needs to be
>>>> routed through a "traits" function, but can rather be done in-line here,
>>>> after each placement new, before deallocation of the original blob of
>>>> memory. Also, I argue it's the right thing to do also for 'm_ggc',
>>>> because even if in that case we're not going to leak memory (GC will
>>>> reclaim), but we still may leak other resources dynamically allocated in
>>>> a non-trivial constructor.)
>>>
>>> Yes, of course, all elements need to be eventually be destroyed.
>>> My only hesitation was whether it should be done via one of these
>>> traits classes (like it's done in C++ containers via allocators)
>>> rather than directly
>>
>> Given that there is (apparently) no issue to do a placement new in
>> 'hash_table::expand', I'd asumme a -- corresponding -- explicit
>> destructor call would be likewise appropriate? (But I'll of course route
>> this through a (new) "traits" function if someone explains why this is
>> the right thing to do.)
>>
>>> and whether there might be other places
>>> where the destruction night need to happen.
>>
>> (Possibly, yes, per discussion above -- but that's a separate issue?)
>>
>>>> The attached "Fix 'hash_table::expand' to destruct stale Value objects"
>>>> does prevent my original problem, does address the current 'class2loc'
>>>> memory leak in 'cp/parser.c' (see commit log for one example), and
>>>> adjusts the new
>>>> 'gcc/hash-map-tests.c:test_map_of_type_with_ctor_and_dtor_expand' test
>>>> case such that number of constructor calls matches the number of
>>>> destructor calls. After some careful review regarding C++ details
>>>> (please!), OK to push to master branch? (Also cherry-pick into release
>>>> branches, eventually?) Is the source code comment that I'm adding
>>>> sufficiently explanatory and correct in C++ terms?
>>
>> Ping.
>>
>>> Shouldn't the hash_table dtor (and perhaps also empty()) also
>>> destroy the elements? (Otherwise, what destroys the elements
>>> newly constructed here, or anywhere else for that matter, such
>>> as in the hash_table ctor?)
>>
>> Per my understanding, per discussion above, they (eventually) do get
>> destroyed via 'delete' in 'typed_delete_remove', for example, via
>> 'Descriptor::remove' calls for all/relevant entries in
>> 'hash_table::~hash_table', 'hash_table::empty_slow',
>> 'hash_table::clear_slot', 'hash_table::remove_elt_with_hash'.
>>
>> (This means that if there has been an intermediate 'expand', this may
>> (eventually) destroy objects at a different memory location from where
>> they originally have been created -- but that's fine.)
>>
>> The 'expand' case itself is different: any (live) entries are *moved*
>> into a new storage memory object via placement new. (And then the
>> hollow entries in the old storage memory object linger.)
>>
>>> Also, shouldn't the destroyed slot be marked either deleted or
>>> empty?)
>>
>> Per my understanding, irrelevant in 'expand': working through 'oentries',
>> the *move* is only done 'if (!is_empty (x) && !is_deleted (x))' (so
>> combined with the item above, there is no memory leak for any entries
>> that have already been 'remove'd -- they have already been destructed),
>> and the whole (old) storage memory object will be deallocated right after
>> the 'oentries' loop.
>>
>>
>>> (Sorry, I realize I have more questions than answers.)
>>
>> No worries, happens to me most of the times! Thanks for looking into
>> this.
>>
>>
>> Grüße
>> Thomas
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>From 2275962abd72acd1636d438d1cb176bbabdcef06 Mon Sep 17 00:00:00 2001
From: Thomas Schwinge <tho...@codesourcery.com>
Date: Fri, 13 Aug 2021 18:03:38 +0200
Subject: [PATCH] Fix 'hash_table::expand' to destruct stale Value objects
Thus plugging potentional memory leaks if these have non-trivial
constructor/destructor.
See
<https://stackoverflow.com/questions/6730403/how-to-delete-object-constructed-via-placement-new-operator>
and others.
As one example, compilation of 'g++.dg/warn/Wmismatched-tags.C' per
'valgrind --leak-check=full' improves as follows:
[...]
-
-104 bytes in 1 blocks are definitely lost in loss record 399 of 519
- at 0x483DFAF: realloc (vg_replace_malloc.c:836)
- by 0x223B62C: xrealloc (xmalloc.c:179)
- by 0xA8D848: void va_heap::reserve<class_decl_loc_t::class_key_loc_t>(vec<class_decl_loc_t::class_key_loc_t, va_heap, vl_embed>*&, unsigned int, bool) (vec.h:290)
- by 0xA8B373: vec<class_decl_loc_t::class_key_loc_t, va_heap, vl_ptr>::reserve(unsigned int, bool) (vec.h:1858)
- by 0xA8B277: vec<class_decl_loc_t::class_key_loc_t, va_heap, vl_ptr>::safe_push(class_decl_loc_t::class_key_loc_t const&) (vec.h:1967)
- by 0xA57481: class_decl_loc_t::add_or_diag_mismatched_tag(tree_node*, tag_types, bool, bool) (parser.c:32967)
- by 0xA573E1: class_decl_loc_t::add(cp_parser*, unsigned int, tag_types, tree_node*, bool, bool) (parser.c:32941)
- by 0xA56C52: cp_parser_check_class_key(cp_parser*, unsigned int, tag_types, tree_node*, bool, bool) (parser.c:32819)
- by 0xA3AD12: cp_parser_elaborated_type_specifier(cp_parser*, bool, bool) (parser.c:20227)
- by 0xA37EF2: cp_parser_type_specifier(cp_parser*, int, cp_decl_specifier_seq*, bool, int*, bool*) (parser.c:18942)
- by 0xA31CDD: cp_parser_decl_specifier_seq(cp_parser*, int, cp_decl_specifier_seq*, int*) (parser.c:15517)
- by 0xA43C71: cp_parser_parameter_declaration(cp_parser*, int, bool, bool*) (parser.c:24242)
-
-168 bytes in 3 blocks are definitely lost in loss record 422 of 519
- at 0x483DFAF: realloc (vg_replace_malloc.c:836)
- by 0x223B62C: xrealloc (xmalloc.c:179)
- by 0xA8D848: void va_heap::reserve<class_decl_loc_t::class_key_loc_t>(vec<class_decl_loc_t::class_key_loc_t, va_heap, vl_embed>*&, unsigned int, bool) (vec.h:290)
- by 0xA8B373: vec<class_decl_loc_t::class_key_loc_t, va_heap, vl_ptr>::reserve(unsigned int, bool) (vec.h:1858)
- by 0xA8B277: vec<class_decl_loc_t::class_key_loc_t, va_heap, vl_ptr>::safe_push(class_decl_loc_t::class_key_loc_t const&) (vec.h:1967)
- by 0xA57481: class_decl_loc_t::add_or_diag_mismatched_tag(tree_node*, tag_types, bool, bool) (parser.c:32967)
- by 0xA573E1: class_decl_loc_t::add(cp_parser*, unsigned int, tag_types, tree_node*, bool, bool) (parser.c:32941)
- by 0xA56C52: cp_parser_check_class_key(cp_parser*, unsigned int, tag_types, tree_node*, bool, bool) (parser.c:32819)
- by 0xA3AD12: cp_parser_elaborated_type_specifier(cp_parser*, bool, bool) (parser.c:20227)
- by 0xA37EF2: cp_parser_type_specifier(cp_parser*, int, cp_decl_specifier_seq*, bool, int*, bool*) (parser.c:18942)
- by 0xA31CDD: cp_parser_decl_specifier_seq(cp_parser*, int, cp_decl_specifier_seq*, int*) (parser.c:15517)
- by 0xA53385: cp_parser_single_declaration(cp_parser*, vec<deferred_access_check, va_gc, vl_embed>*, bool, bool, bool*) (parser.c:31072)
-
-488 bytes in 7 blocks are definitely lost in loss record 449 of 519
- at 0x483DFAF: realloc (vg_replace_malloc.c:836)
- by 0x223B62C: xrealloc (xmalloc.c:179)
- by 0xA8D848: void va_heap::reserve<class_decl_loc_t::class_key_loc_t>(vec<class_decl_loc_t::class_key_loc_t, va_heap, vl_embed>*&, unsigned int, bool) (vec.h:290)
- by 0xA8B373: vec<class_decl_loc_t::class_key_loc_t, va_heap, vl_ptr>::reserve(unsigned int, bool) (vec.h:1858)
- by 0xA8B277: vec<class_decl_loc_t::class_key_loc_t, va_heap, vl_ptr>::safe_push(class_decl_loc_t::class_key_loc_t const&) (vec.h:1967)
- by 0xA57481: class_decl_loc_t::add_or_diag_mismatched_tag(tree_node*, tag_types, bool, bool) (parser.c:32967)
- by 0xA573E1: class_decl_loc_t::add(cp_parser*, unsigned int, tag_types, tree_node*, bool, bool) (parser.c:32941)
- by 0xA56C52: cp_parser_check_class_key(cp_parser*, unsigned int, tag_types, tree_node*, bool, bool) (parser.c:32819)
- by 0xA3AD12: cp_parser_elaborated_type_specifier(cp_parser*, bool, bool) (parser.c:20227)
- by 0xA37EF2: cp_parser_type_specifier(cp_parser*, int, cp_decl_specifier_seq*, bool, int*, bool*) (parser.c:18942)
- by 0xA31CDD: cp_parser_decl_specifier_seq(cp_parser*, int, cp_decl_specifier_seq*, int*) (parser.c:15517)
- by 0xA49508: cp_parser_member_declaration(cp_parser*) (parser.c:26440)
-
-728 bytes in 7 blocks are definitely lost in loss record 455 of 519
- at 0x483B7F3: malloc (vg_replace_malloc.c:309)
- by 0x223B63F: xrealloc (xmalloc.c:177)
- by 0xA8D848: void va_heap::reserve<class_decl_loc_t::class_key_loc_t>(vec<class_decl_loc_t::class_key_loc_t, va_heap, vl_embed>*&, unsigned int, bool) (vec.h:290)
- by 0xA8B373: vec<class_decl_loc_t::class_key_loc_t, va_heap, vl_ptr>::reserve(unsigned int, bool) (vec.h:1858)
- by 0xA57508: class_decl_loc_t::add_or_diag_mismatched_tag(tree_node*, tag_types, bool, bool) (parser.c:32980)
- by 0xA573E1: class_decl_loc_t::add(cp_parser*, unsigned int, tag_types, tree_node*, bool, bool) (parser.c:32941)
- by 0xA56C52: cp_parser_check_class_key(cp_parser*, unsigned int, tag_types, tree_node*, bool, bool) (parser.c:32819)
- by 0xA48BC6: cp_parser_class_head(cp_parser*, bool*) (parser.c:26090)
- by 0xA4674B: cp_parser_class_specifier_1(cp_parser*) (parser.c:25302)
- by 0xA47D76: cp_parser_class_specifier(cp_parser*) (parser.c:25680)
- by 0xA37E27: cp_parser_type_specifier(cp_parser*, int, cp_decl_specifier_seq*, bool, int*, bool*) (parser.c:18912)
- by 0xA31CDD: cp_parser_decl_specifier_seq(cp_parser*, int, cp_decl_specifier_seq*, int*) (parser.c:15517)
-
-832 bytes in 8 blocks are definitely lost in loss record 458 of 519
- at 0x483B7F3: malloc (vg_replace_malloc.c:309)
- by 0x223B63F: xrealloc (xmalloc.c:177)
- by 0xA8D848: void va_heap::reserve<class_decl_loc_t::class_key_loc_t>(vec<class_decl_loc_t::class_key_loc_t, va_heap, vl_embed>*&, unsigned int, bool) (vec.h:290)
- by 0xA901ED: bool vec_safe_reserve<class_decl_loc_t::class_key_loc_t, va_heap>(vec<class_decl_loc_t::class_key_loc_t, va_heap, vl_embed>*&, unsigned int, bool) (vec.h:697)
- by 0xA8F161: void vec_alloc<class_decl_loc_t::class_key_loc_t, va_heap>(vec<class_decl_loc_t::class_key_loc_t, va_heap, vl_embed>*&, unsigned int) (vec.h:718)
- by 0xA8D18D: vec<class_decl_loc_t::class_key_loc_t, va_heap, vl_embed>::copy() const (vec.h:979)
- by 0xA8B0C3: vec<class_decl_loc_t::class_key_loc_t, va_heap, vl_ptr>::copy() const (vec.h:1824)
- by 0xA896B1: class_decl_loc_t::operator=(class_decl_loc_t const&) (parser.c:32697)
- by 0xA571FD: class_decl_loc_t::add(cp_parser*, unsigned int, tag_types, tree_node*, bool, bool) (parser.c:32899)
- by 0xA56C52: cp_parser_check_class_key(cp_parser*, unsigned int, tag_types, tree_node*, bool, bool) (parser.c:32819)
- by 0xA3AD12: cp_parser_elaborated_type_specifier(cp_parser*, bool, bool) (parser.c:20227)
- by 0xA37EF2: cp_parser_type_specifier(cp_parser*, int, cp_decl_specifier_seq*, bool, int*, bool*) (parser.c:18942)
-
-1,144 bytes in 11 blocks are definitely lost in loss record 466 of 519
- at 0x483B7F3: malloc (vg_replace_malloc.c:309)
- by 0x223B63F: xrealloc (xmalloc.c:177)
- by 0xA8D848: void va_heap::reserve<class_decl_loc_t::class_key_loc_t>(vec<class_decl_loc_t::class_key_loc_t, va_heap, vl_embed>*&, unsigned int, bool) (vec.h:290)
- by 0xA901ED: bool vec_safe_reserve<class_decl_loc_t::class_key_loc_t, va_heap>(vec<class_decl_loc_t::class_key_loc_t, va_heap, vl_embed>*&, unsigned int, bool) (vec.h:697)
- by 0xA8F161: void vec_alloc<class_decl_loc_t::class_key_loc_t, va_heap>(vec<class_decl_loc_t::class_key_loc_t, va_heap, vl_embed>*&, unsigned int) (vec.h:718)
- by 0xA8D18D: vec<class_decl_loc_t::class_key_loc_t, va_heap, vl_embed>::copy() const (vec.h:979)
- by 0xA8B0C3: vec<class_decl_loc_t::class_key_loc_t, va_heap, vl_ptr>::copy() const (vec.h:1824)
- by 0xA896B1: class_decl_loc_t::operator=(class_decl_loc_t const&) (parser.c:32697)
- by 0xA571FD: class_decl_loc_t::add(cp_parser*, unsigned int, tag_types, tree_node*, bool, bool) (parser.c:32899)
- by 0xA56C52: cp_parser_check_class_key(cp_parser*, unsigned int, tag_types, tree_node*, bool, bool) (parser.c:32819)
- by 0xA48BC6: cp_parser_class_head(cp_parser*, bool*) (parser.c:26090)
- by 0xA4674B: cp_parser_class_specifier_1(cp_parser*) (parser.c:25302)
-
-1,376 bytes in 10 blocks are definitely lost in loss record 467 of 519
- at 0x483DFAF: realloc (vg_replace_malloc.c:836)
- by 0x223B62C: xrealloc (xmalloc.c:179)
- by 0xA8D848: void va_heap::reserve<class_decl_loc_t::class_key_loc_t>(vec<class_decl_loc_t::class_key_loc_t, va_heap, vl_embed>*&, unsigned int, bool) (vec.h:290)
- by 0xA8B373: vec<class_decl_loc_t::class_key_loc_t, va_heap, vl_ptr>::reserve(unsigned int, bool) (vec.h:1858)
- by 0xA8B277: vec<class_decl_loc_t::class_key_loc_t, va_heap, vl_ptr>::safe_push(class_decl_loc_t::class_key_loc_t const&) (vec.h:1967)
- by 0xA57481: class_decl_loc_t::add_or_diag_mismatched_tag(tree_node*, tag_types, bool, bool) (parser.c:32967)
- by 0xA573E1: class_decl_loc_t::add(cp_parser*, unsigned int, tag_types, tree_node*, bool, bool) (parser.c:32941)
- by 0xA56C52: cp_parser_check_class_key(cp_parser*, unsigned int, tag_types, tree_node*, bool, bool) (parser.c:32819)
- by 0xA3AD12: cp_parser_elaborated_type_specifier(cp_parser*, bool, bool) (parser.c:20227)
- by 0xA37EF2: cp_parser_type_specifier(cp_parser*, int, cp_decl_specifier_seq*, bool, int*, bool*) (parser.c:18942)
- by 0xA31CDD: cp_parser_decl_specifier_seq(cp_parser*, int, cp_decl_specifier_seq*, int*) (parser.c:15517)
- by 0xA301E0: cp_parser_simple_declaration(cp_parser*, bool, tree_node**) (parser.c:14772)
-
-3,552 bytes in 33 blocks are definitely lost in loss record 483 of 519
- at 0x483B7F3: malloc (vg_replace_malloc.c:309)
- by 0x223B63F: xrealloc (xmalloc.c:177)
- by 0xA8D848: void va_heap::reserve<class_decl_loc_t::class_key_loc_t>(vec<class_decl_loc_t::class_key_loc_t, va_heap, vl_embed>*&, unsigned int, bool) (vec.h:290)
- by 0xA901ED: bool vec_safe_reserve<class_decl_loc_t::class_key_loc_t, va_heap>(vec<class_decl_loc_t::class_key_loc_t, va_heap, vl_embed>*&, unsigned int, bool) (vec.h:697)
- by 0xA8F161: void vec_alloc<class_decl_loc_t::class_key_loc_t, va_heap>(vec<class_decl_loc_t::class_key_loc_t, va_heap, vl_embed>*&, unsigned int) (vec.h:718)
- by 0xA8D18D: vec<class_decl_loc_t::class_key_loc_t, va_heap, vl_embed>::copy() const (vec.h:979)
- by 0xA8B0C3: vec<class_decl_loc_t::class_key_loc_t, va_heap, vl_ptr>::copy() const (vec.h:1824)
- by 0xA8964A: class_decl_loc_t::class_decl_loc_t(class_decl_loc_t const&) (parser.c:32689)
- by 0xA8F515: hash_table<hash_map<tree_decl_hash, class_decl_loc_t, simple_hashmap_traits<default_hash_traits<tree_decl_hash>, class_decl_loc_t> >::hash_entry, false, xcallocator>::expand() (hash-table.h:839)
- by 0xA8D4B3: hash_table<hash_map<tree_decl_hash, class_decl_loc_t, simple_hashmap_traits<default_hash_traits<tree_decl_hash>, class_decl_loc_t> >::hash_entry, false, xcallocator>::find_slot_with_hash(tree_node* const&, unsigned int, insert_option) (hash-table.h:1008)
- by 0xA8B1DC: hash_map<tree_decl_hash, class_decl_loc_t, simple_hashmap_traits<default_hash_traits<tree_decl_hash>, class_decl_loc_t> >::get_or_insert(tree_node* const&, bool*) (hash-map.h:200)
- by 0xA57128: class_decl_loc_t::add(cp_parser*, unsigned int, tag_types, tree_node*, bool, bool) (parser.c:32888)
[...]
LEAK SUMMARY:
- definitely lost: 8,440 bytes in 81 blocks
+ definitely lost: 48 bytes in 1 blocks
indirectly lost: 12,529 bytes in 329 blocks
possibly lost: 0 bytes in 0 blocks
still reachable: 1,644,376 bytes in 768 blocks
gcc/
* hash-table.h (hash_table<Descriptor, Lazy, Allocator>::expand):
Destruct stale Value objects.
* hash-map-tests.c (test_map_of_type_with_ctor_and_dtor_expand):
Update.
---
gcc/hash-map-tests.c | 10 ++++++----
gcc/hash-table.h | 4 ++++
2 files changed, 10 insertions(+), 4 deletions(-)
diff --git a/gcc/hash-map-tests.c b/gcc/hash-map-tests.c
index 6acc0d4337e..511d4342087 100644
--- a/gcc/hash-map-tests.c
+++ b/gcc/hash-map-tests.c
@@ -305,31 +305,32 @@ test_map_of_type_with_ctor_and_dtor ()
m.get_or_insert (a[i]);
ASSERT_EQ (val_t::ndefault, 1 + i);
ASSERT_EQ (val_t::ncopy, 0);
ASSERT_EQ (val_t::nassign, 0);
ASSERT_EQ (val_t::ndtor, i);
m.remove (a[i]);
ASSERT_EQ (val_t::ndefault, 1 + i);
ASSERT_EQ (val_t::ncopy, 0);
ASSERT_EQ (val_t::nassign, 0);
ASSERT_EQ (val_t::ndtor, 1 + i);
}
}
}
-/* Verify aspects of 'hash_table::expand'. */
+/* Verify aspects of 'hash_table::expand', in particular that it doesn't leak
+ Value objects. */
static void
test_map_of_type_with_ctor_and_dtor_expand (bool remove_some_inline)
{
/* Configure, so that hash table expansion triggers a few times. */
const size_t N_init = 0;
const int N_elem = 70;
size_t expand_c_expected = 4;
size_t expand_c = 0;
/* For stability of this testing, we need all Key values 'k' to produce
unique hash values 'Traits::hash (k)', as otherwise the dynamic
insert/remove behavior may diverge across different architectures. This
is, for example, a problem when using the standard 'pointer_hash::hash',
which is simply doing a 'k >> 3' operation, which is fine on 64-bit
@@ -388,69 +389,70 @@ test_map_of_type_with_ctor_and_dtor_expand (bool remove_some_inline)
unsigned int nindex = hash_table_higher_prime_index (elts * 2);
m_size = prime_tab[nindex].prime;
}
m_n_deleted = 0;
/* All non-deleted elements have been moved. */
n_expand_moved += i;
if (remove_some_inline)
n_expand_moved -= (i + 2) / 3;
}
ASSERT_EQ (val_t::ndefault, 1 + i);
ASSERT_EQ (val_t::ncopy, n_expand_moved);
ASSERT_EQ (val_t::nassign, 0);
if (remove_some_inline)
- ASSERT_EQ (val_t::ndtor, (i + 2) / 3);
+ ASSERT_EQ (val_t::ndtor, n_expand_moved + (i + 2) / 3);
else
- ASSERT_EQ (val_t::ndtor, 0);
+ ASSERT_EQ (val_t::ndtor, n_expand_moved);
/* Remove some inline. This never triggers an 'expand' here, but via
'm_n_deleted' does influence any following one. */
if (remove_some_inline
&& !(i % 3))
{
m.remove (a[i]);
/* Per 'hash_table::remove_elt_with_hash'. */
m_n_deleted++;
ASSERT_EQ (val_t::ndefault, 1 + i);
ASSERT_EQ (val_t::ncopy, n_expand_moved);
ASSERT_EQ (val_t::nassign, 0);
- ASSERT_EQ (val_t::ndtor, 1 + (i + 2) / 3);
+ ASSERT_EQ (val_t::ndtor, n_expand_moved + 1 + (i + 2) / 3);
}
}
ASSERT_EQ (expand_c, expand_c_expected);
int ndefault = val_t::ndefault;
int ncopy = val_t::ncopy;
int nassign = val_t::nassign;
int ndtor = val_t::ndtor;
for (int i = 0; i < N_elem; ++i)
{
if (remove_some_inline
&& !(i % 3))
continue;
m.remove (a[i]);
++ndtor;
ASSERT_EQ (val_t::ndefault, ndefault);
ASSERT_EQ (val_t::ncopy, ncopy);
ASSERT_EQ (val_t::nassign, nassign);
ASSERT_EQ (val_t::ndtor, ndtor);
}
+ ASSERT_EQ (val_t::ndefault + val_t::ncopy, val_t::ndtor);
}
/* Test calling empty on a hash_map that has a key type with non-zero
"empty" value. */
static void
test_nonzero_empty_key ()
{
typedef int_hash<int, INT_MIN, INT_MAX> IntHash;
hash_map<int, int, simple_hashmap_traits<IntHash, int> > x;
for (int i = 1; i != 32; ++i)
x.put (i, i);
ASSERT_EQ (x.get (0), NULL);
diff --git a/gcc/hash-table.h b/gcc/hash-table.h
index a6e0ac8eea9..8c2a0589fbd 100644
--- a/gcc/hash-table.h
+++ b/gcc/hash-table.h
@@ -808,30 +808,34 @@ hash_table<Descriptor, Lazy, Allocator>::expand ()
m_entries = nentries;
m_size = nsize;
m_size_prime_index = nindex;
m_n_elements -= m_n_deleted;
m_n_deleted = 0;
value_type *p = oentries;
do
{
value_type &x = *p;
if (!is_empty (x) && !is_deleted (x))
{
value_type *q = find_empty_slot_for_expand (Descriptor::hash (x));
new ((void*) q) value_type (std::move (x));
+
+ /* Manually invoke destructor of original object, to counterbalance
+ object constructed via placement new. */
+ x.~value_type ();
}
p++;
}
while (p < olimit);
if (!m_ggc)
Allocator <value_type> ::data_free (oentries);
else
ggc_free (oentries);
}
/* Implements empty() in cases where it isn't a no-op. */
template<typename Descriptor, bool Lazy,
--
2.30.2
