[Bug c/106778] New: libcpp/makeuname2c.cc:454: sanity check in wrong place ?

[Bug c/106778] New: libcpp/makeuname2c.cc:454: sanity check in wrong place ?

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106778

            Bug ID: 106778
           Summary: libcpp/makeuname2c.cc:454: sanity check in wrong place
                    ?
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: dcb314 at hotmail dot com
  Target Milestone: ---

Static analyser cppcheck can be made to say:

libcpp/makeuname2c.cc:454:19: style: Array index 'off' is used before limits
check. [arrayIndexThenCheck]

Source code is

      assert (tree[off] == 0 && off < tree_size);

Suggest sanity check array index before use, not after.

[Bug c/106778] libcpp/makeuname2c.cc:454: sanity check in wrong place ?

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106778

David Binderman <dcb314 at hotmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #1 from David Binderman <dcb314 at hotmail dot com> ---
Adding author of code.

[Bug preprocessor/106778] libcpp/makeuname2c.cc:454: sanity check in wrong place ?

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106778

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |jakub at gcc dot gnu.org
   Last reconfirmed|                            |2022-08-30

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Nothing important, but will change after testing.

[Bug preprocessor/106778] libcpp/makeuname2c.cc:454: sanity check in wrong place ?

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106778

--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:b3048b6ffb126a4624f66bad713fe6d1dc6dc13d

commit r13-2301-gb3048b6ffb126a4624f66bad713fe6d1dc6dc13d
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Wed Aug 31 10:22:36 2022 +0200

    libcpp: Make static checkers happy about makeuname2c [PR106778]

    The assertion ensures that we point within the image and at a byte
    we haven't touched yet (or at least that it isn't the first byte
    of an already stored tree), some static checker was unhappy about
    first checking that it is zero and only afterwards checking that it
    is within bounds.

    2022-08-31  Jakub Jelinek  <jakub@redhat.com>

            PR preprocessor/106778
            * makeuname2c.cc (write_nodes): Reverse order of && operands in
            assert.

[Bug preprocessor/106778] libcpp/makeuname2c.cc:454: sanity check in wrong place ?

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106778

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Changed now.