[Bug analyzer/99738] New: RFE: analyzer should complain about unchecked FILE *

[Bug analyzer/99738] New: RFE: analyzer should complain about unchecked FILE *

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99738

            Bug ID: 99738
           Summary: RFE: analyzer should complain about unchecked FILE *
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: analyzer
          Assignee: dmalcolm at gcc dot gnu.org
          Reporter: dmalcolm at gcc dot gnu.org
  Target Milestone: ---

In PR 99716 I noted we don't complain about the fprintf in:

    FILE *fp = fopen ("/tmp/test", "w");
    fprintf (fp, "hello");
    fclose (fp);

This becomes the following at the gimple ssa level:

  fp_7 = fopen ("/tmp/test", "w");
  __builtin_fwrite ("hello", 1, 5, fp_7);
  fclose (fp_7);

and we have:
DEF_LIB_BUILTIN  (BUILT_IN_FWRITE, "fwrite", 
                  BT_FN_SIZE_CONST_PTR_SIZE_SIZE_FILEPTR, ATTR_NONNULL_LIST)

so we should have complained due to the ATTR_NONNULL_LIST due to fp_7 being in
the "unchecked" state in the "file" state machine.

Turns out that sm-file.cc doesn't yet implement checks for the "unchecked"
state, and probably should (or somehow be merged with sm-malloc.cc).

Filing this here as it's probably a bit late to be adding this for GCC 11.