https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106092
Bug ID: 106092
Summary: Bogus -Wfree-nonheap-object
Product: gcc
Version: 11.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: lavr at ncbi dot nlm.nih.gov
Target Milestone: ---
I got the following report from the compilation:
In file included from /home/ANTON/cxx/src/util/qparse/parser.cpp:352:
query_parser_bison.tab.c: In function ‘int ncbi_q_parse(void*)’:
query_parser_bison.tab.c:2354:18: warning: ‘void free(void*)’ called on
unallocated object ‘yyssa’ [-Wfree-nonheap-object]
In file included from /home/ANTON/cxx/src/util/qparse/parser.cpp:352:
query_parser_bison.tab.c:1351:18: note: declared here
The thing is, the code which is "blamed", looks like this (line numbers on):
2353 if (yyss != yyssa)
2354 YYSTACK_FREE (yyss);
which obviously tells NOT to free if the "yyss" is the same as "yyssa"...
So it's unclear from which context GCC "figured" that yyssa is going to be
freed.
The declarations look like this:
1350 /* The state stack. */
1351 yytype_int16 yyssa[YYINITDEPTH];
1352 yytype_int16 *yyss;
1353 yytype_int16 *yyssp;
1384 yyss = yyssa;
so at some point, yyss gets assigned with yyssa. But then again, the code
instructs exactly NOT to free, in this case. There's nothing to warn about.
