Question about GCC not warning for some noncompliant SEI CERT C code examples

[Fredrik Hederstierna <fredrik.hederstierna@verisure.com>]

Hi

When reading the SEI CERT C Coding Standard rules, looking at
"DCL30-C. Declare objects with appropriate storage durations"
it seem like GCC does not warn in compile-time for some noncompliant examples.

I know eg AddressSanitizer and several runtime running tools finds these bugs,
but it would be convenient of GCC could do some basic static analysis already in compile-time to avoid bad code generation.
Some static analysers finds these bugs, but not all, and GCC does not warn.

Example from DCL30-C, not warned by GCC:


/* NONCOMPLIANT EXAMPLE-1 */
#include <stdio.h>
const char *p;
void dont_do_this(void) {
  const char c_str[] = "This will change";
  p = c_str; /* Dangerous */
}
void innocuous(void) {
  printf("%s\n", p);
}
int main(void) {
  dont_do_this();
  innocuous();
  return 0;
}


/* NONCOMPLIANT EXAMPLE-2 */
void squirrel_away(char **ptr_param) {
  char local[10];
  /* Initialize array */
  *ptr_param = local;
}
void rodent(void) {
  char *ptr;
  squirrel_away(&ptr);
  /* ptr is live but invalid here */
}

Question, where in GCC is the most appropriate place to implements such a checker?
I know there are some warnings for return-local-addr, and null-pointer-dereference in some different parts, but this seems different?
Can it be found be points-to analysis, or where is it best to put this warning if being implemented?

Reference:
https://wiki.sei.cmu.edu/confluence/display/c/DCL30-C.+Declare+objects+with+appropriate+storage+durations