[PATCH] plug memory leaks in warn_parm_array_mismatch (PR 99055)
Richard Biener
richard.guenther@gmail.com
Thu Feb 11 07:59:25 GMT 2021
On Wed, Feb 10, 2021 at 6:16 PM Martin Sebor <msebor@gmail.com> wrote:
>
> The attached patch replaces calls to print_generic_expr_to_str() with
> a helper function that returns a std::string and releases the caller
> from the responsibility to explicitly free memory.
I don't like this. What's the reason to use generic_expr_as_string
anyway? We have %E pretty-printers after all. Couldn't you have
fixed the leak by doing
if (newbnd)
free (newbndstr);
etc.?
> With the patch installed, Valgrind shows more leaks in this code that
> I'm not sure what to do about:
>
> 1) A tree built by build_type_attribute_qual_variant() called from
> attr_access::array_as_string() to build a temporary type only
> for the purposes of formatting it.
>
> 2) A tree (an attribute list) built by tree_cons() called from
> build_attr_access_from_parms() that's used only for the duration
> of the caller.
>
> Do these temporary trees need to be released somehow or are the leaks
> expected?
You should configure GCC with --enable-valgrind-annotations to make
it aware of our GC.
> Martin
>
> Leak 1:
> ==7112== 56 bytes in 1 blocks are still reachable in loss record 73 of 691
> ==7112== at 0x483AB1A: calloc (vg_replace_malloc.c:762)
> ==7112== by 0x294ED71: xcalloc (xmalloc.c:162)
> ==7112== by 0xB8B21D: alloc_page(unsigned int) (ggc-page.c:918)
> ==7112== by 0xB8BAD1: ggc_internal_alloc(unsigned long, void
> (*)(void*), unsigned long, unsigned long) (ggc-page.c:1294)
> ==7112== by 0x9E1F33: ggc_internal_alloc(unsigned long) (ggc.h:130)
> ==7112== by 0x198AB1A: ggc_alloc_tree_node_stat(unsigned long)
> (ggc.h:309)
> ==7112== by 0x193BD18: copy_node(tree_node*) (tree.c:1223)
> ==7112== by 0x1953BDD: build_distinct_type_copy(tree_node*) (tree.c:6730)
> ==7112== by 0x9A1379: build_type_attribute_qual_variant(tree_node*,
> tree_node*, int) (attribs.c:1161)
> ==7112== by 0x9A483D:
> attr_access::array_as_string[abi:cxx11](tree_node*) const (attribs.c:2332)
> ==7112== by 0xB7C5A7: warn_parm_array_mismatch(unsigned int,
> tree_node*, tree_node*) (c-warn.c:3449)
> ==7112== by 0xA3EB57: c_parser_declaration_or_fndef(c_parser*, bool,
> bool, bool, bool, bool, tree_node**, vec<c_token, va_heap, vl_ptr>,
> bool, tree_node*, oacc_routine_data*, bool*) (c-parser.c:2342)
>
>
> Leak 2:
> ==7112== 64 bytes in 1 blocks are still reachable in loss record 150 of 691
> ==7112== at 0x483AB1A: calloc (vg_replace_malloc.c:762)
> ==7112== by 0x294ED71: xcalloc (xmalloc.c:162)
> ==7112== by 0xB8B21D: alloc_page(unsigned int) (ggc-page.c:918)
> ==7112== by 0xB8BAD1: ggc_internal_alloc(unsigned long, void
> (*)(void*), unsigned long, unsigned long) (ggc-page.c:1294)
> ==7112== by 0x9E1F33: ggc_internal_alloc(unsigned long) (ggc.h:130)
> ==7112== by 0x198AB1A: ggc_alloc_tree_node_stat(unsigned long)
> (ggc.h:309)
> ==7112== by 0x19433E6: tree_cons(tree_node*, tree_node*, tree_node*)
> (tree.c:3331)
> ==7112== by 0xB67188: build_attr_access_from_parms(tree_node*, bool)
> (c-attribs.c:5060)
> ==7112== by 0xB7C008: warn_parm_array_mismatch(unsigned int,
> tree_node*, tree_node*) (c-warn.c:3364)
> ==7112== by 0xA3EB57: c_parser_declaration_or_fndef(c_parser*, bool,
> bool, bool, bool, bool, tree_node**, vec<c_token, va_heap, vl_ptr>,
> bool, tree_node*, oacc_routine_data*, bool*) (c-parser.c:2342)
> ==7112== by 0xA3D5A9: c_parser_external_declaration(c_parser*)
> (c-parser.c:1777)
> ==7112== by 0xA3D06A: c_parser_translation_unit(c_parser*)
> (c-parser.c:1650)
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