[Bug c/50476] New: Warn of pointer set to object whose lifetime is limited

[rui.maciel at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50476

             Bug #: 50476
           Summary: Warn of pointer set to object whose lifetime is
                    limited
    Classification: Unclassified
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: c
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: rui.maciel@gmail.com


Consider the following code:

<code>
#include <stdio.h>

int *x = NULL;

void f(void)
{
        int y = 1;

        x = &y;
}


int main(void)
{
        f();

        printf("int: %d\n", *x);

        return 0;
}

</code>

Function f() assigns a global pointer to a local object, so that the global
pointer refers to the local object's address even when the object's lifetime
ends.  This represents undefined behaviour, and therefore can be a potential
source of problems.  It would be great if gcc at least threw a warning
informing the user of this problem, similar to how Bug 14156 handles it's use
case.