This is the mail archive of the
gcc-bugs@gcc.gnu.org
mailing list for the GCC project.
preprocessor/4976: cpp fails to warn about macro redefinitions
- From: fredette at mit dot edu
- To: gcc-gnats at gcc dot gnu dot org
- Date: 30 Nov 2001 22:06:44 -0000
- Subject: preprocessor/4976: cpp fails to warn about macro redefinitions
- Reply-to: fredette at mit dot edu
[Get raw message]
>Number: 4976
>Category: preprocessor
>Synopsis: cpp fails to warn about macro redefinitions
>Confidential: no
>Severity: serious
>Priority: high
>Responsible: unassigned
>State: open
>Class: sw-bug
>Submitter-Id: net
>Arrival-Date: Fri Nov 30 14:16:01 PST 2001
>Closed-Date:
>Last-Modified:
>Originator: Matthew Fredette
>Release: gcc-3.0.2
>Organization:
>Environment:
NetBSD the-gates-of-delirium.home 1.5W NetBSD 1.5W (THE-GATES-OF-DELIRIUM) #3: Fri Jul 13 09:31:17 EDT 2001 root@the-gates-of-delirium:/data/union-i386/src/sys/arch/i386/compile/THE-GATES-OF-DELIRIUM i386
>Description:
cpp fails to warn about macro redefinitions.
gcc/gcc/cppmacro.c revision 1.46 introduced the NODE_WARN flag, with
this code at the end of the _cpp_create_definition function:
if (! ustrncmp (node->name, DSC ("__STDC_")))
node->flags |= NODE_WARN;
It is this NODE_WARN flag that is supposed to trigger (through the
warn_of_redefinition function) a warning when a macro is redefined.
The test seems wrong - as ustrncmp behaves like strncmp, this test
will fail for all macros other than __STDC__. I.e., only a
redefined __STDC__ macro node will happen to get this flag.
Further, gcc/gcc/cpplib.c revision 1.240, in the do_undef function,
replaced a check of NODE_BUILTIN with NODE_WARN. Assuming
that normal macros are supposed to be tagged with NODE_WARN,
this check is also wrong, because it will cause a warning
whenever a normal macro is undefined.
>How-To-Repeat:
Try to preprocess a file that defines a macro, then redefines
it with a different value.
>Fix:
Remove the ! from the test at line 1426 of gcc/gcc/cppmacro.c, revision 1.87.
Replace NODE_WARN with NODE_BUILTIN at line 496 of gcc/gcc/gcclib.c, revision 1.287.
>Release-Note:
>Audit-Trail:
>Unformatted: