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List: gcc
Subject: Fix 'hash_table::expand' to destruct stale Value objects (was: 'hash_map<tree, hash_map<tree, tree>>
From: Thomas Schwinge <thomas () codesourcery ! com>
Date: 2021-08-30 10:46:32
Message-ID: 87h7f7mcqf.fsf () euler ! schwinge ! homeip ! net
[Download RAW message or body]
Hi!
Ping -- we still need to plug the memory leak; see patch attached, and/or
long discussion here:
On 2021-08-16T14:10:00-0600, Martin Sebor <msebor@gmail.com> wrote:
> On 8/16/21 6:44 AM, Thomas Schwinge wrote:
> > On 2021-08-12T17:15:44-0600, Martin Sebor via Gcc <gcc@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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["0001-Fix-hash_table-expand-to-destruct-stale-Value-object.patch" (text/x-diff)]
From 2275962abd72acd1636d438d1cb176bbabdcef06 Mon Sep 17 00:00:00 2001
From: Thomas Schwinge <thomas@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
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