‘void free(void*)’ called on unallocated object ‘yyssa’ [-Wfree-nonheap-object]

[Christoph Grüninger]

Dear Bison community,
while compiling CMake using GCC 11 (not yet released), I came across 
several -Wfree-nonheap-object warnings. They came from a file generated 
by GNU Bison 3.4.2. [1]

I was hoping the error might be fixed in a newer version, so
1. I downloaded your latest release 3.7.4
2. Re-generated the file cmCommandArgumentParser.y with
     bison --yacc --name-prefix=cmCommandArgument_yy 
--defines=cmCommandArgumentParserTokens.h -ocmCommandArgumentParser.cxx 
cmCommandArgumentParser.y
3. I removed the lines 1717 and 1745 as the label yyerrlab1 must be defined.
4. I recompiled CMake and get the following error:
    Scanning dependencies of target CMakeLib
    [ 54%] Building CXX object 
Source/CMakeFiles/CMakeLib.dir/LexerParser/cmCommandArgumentParser.cxx.o
    cmCommandArgumentParser.cxx: In function ‘int 
cmCommandArgument_yyparse(yyscan_t)’:
    cmCommandArgumentParser.cxx:1838:18: warning: ‘void free(void*)’ 
called on unallocated object ‘yyssa’ [-Wfree-nonheap-object]
    cmCommandArgumentParser.cxx:1203:16: note: declared here

I attached both the .y and he generated .cxx file.

Is this a known issue? Is the GCC 11 warning wrong (false positive)? I 
assume not, as yyssa is an array:
    yy_state_t yyssa[YYINITDEPTH];

Can you change Bison that it will generate code that behaves correctly?

Bye
Christoph


[1] CMake issue 21710: gitlab.kitware.com/cmake/cmake/-/issues/21710


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cmCommandArgumentParser.y
Description: Text document

cmCommandArgumentParser.cxx
Description: Text Data