[Bug middle-end/92940] incorrect offset and size in -Wstringop-overflow for out-of-bounds store into VLA and two offset ranges

[Bug middle-end/92940] incorrect offset and size in -Wstringop-overflow for out-of-bounds store into VLA and two offset ranges

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92940

Martin Sebor <msebor at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2020-11-03
     Ever confirmed|0                           |1
           Keywords|                            |patch
           Assignee|unassigned at gcc dot gnu.org      |msebor at gcc dot gnu.org
             Status|UNCONFIRMED                 |ASSIGNED

--- Comment #2 from Martin Sebor <msebor at gcc dot gnu.org> ---
Fixed in the following patch for pr92936:
https://gcc.gnu.org/pipermail/gcc-patches/2020-November/557807.html

[Bug middle-end/92940] incorrect offset and size in -Wstringop-overflow for out-of-bounds store into VLA and two offset ranges

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92940

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

https://gcc.gnu.org/g:eafe8ee7af13c39805ea09bbf5b4f9ab2a48304a

commit r11-5523-geafe8ee7af13c39805ea09bbf5b4f9ab2a48304a
Author: Martin Sebor <msebor@redhat.com>
Date:   Sun Nov 29 15:09:30 2020 -0700

    Handle PHIs in compute_objsize.

    PR middle-end/92936 - missing warning on a past-the-end store to a PHI
    PR middle-end/92940 - incorrect offset and size in -Wstringop-overflow for
out-of-bounds store into VLA and two offset ranges
    PR middle-end/89428 - missing -Wstringop-overflow on a PHI with variable
offset

    gcc/ChangeLog:

            PR middle-end/92936
            PR middle-end/92940
            PR middle-end/89428
            * builtins.c (access_ref::access_ref): Initialize member.
            (access_ref::phi): New function.
            (access_ref::get_ref): New function.
            (access_ref::add_offset): Remove duplicate assignment.
            (maybe_warn_for_bound): Add "maybe" kind of warning messages.
            (warn_for_access): Same.
            (inform_access): Rename...
            (access_ref::inform_access): ...to this.  Print PHI arguments. 
Format
            offset the same as size and simplify.  Improve printing of
allocation
            functions and VLAs.
            (check_access): Adjust to the above.
            (gimple_parm_array_size): Change argument.
            (handle_min_max_size): New function.
            * builtins.h (class ssa_name_limit_t): Move class here from
            tree-ssa-strlen.c.
            (struct access_ref): Declare new members.
            (gimple_parm_array_size): Change argument.
            * tree-ssa-strlen.c (maybe_warn_overflow): Use access_ref and
simplify.
            (handle_builtin_memcpy): Correct argument passed to
maybe_warn_overflow.
            (handle_builtin_memset): Same.
            (class ssa_name_limit_t): Move class to builtins.{h,c}.

    gcc/testsuite/ChangeLog:

            PR middle-end/92936
            PR middle-end/92940
            PR middle-end/89428
            * c-c++-common/Wstringop-overflow-2.c: Adjust text of expected
            informational notes.
            * g++.dg/warn/Wstringop-overflow-3.C: Same.
            * g++.dg/warn/Wplacement-new-size.C: Remove a test for a no longer
            issued warning.
            * gcc.dg/Warray-bounds-43.c: Removed unused declarations.
            * gcc.dg/Wstringop-overflow-11.c: Remove xfails.
            * gcc.dg/Wstringop-overflow-12.c: Same.
            * gcc.dg/Wstringop-overflow-17.c: Adjust text of expected messages.
            * gcc.dg/Wstringop-overflow-27.c: Same.  Remove xfails.
            * gcc.dg/Wstringop-overflow-28.c: Adjust text of expected messages.
            * gcc.dg/Wstringop-overflow-29.c: Same.
            * gcc.dg/Wstringop-overflow-37.c: Same.
            * gcc.dg/Wstringop-overflow-46.c: Same.
            * gcc.dg/Wstringop-overflow-47.c: Same.
            * gcc.dg/Wstringop-overflow-54.c: Same.
            * gcc.dg/warn-strnlen-no-nul.c: Add expected warning.
            * gcc.dg/Wstringop-overflow-7.c: New test.
            * gcc.dg/Wstringop-overflow-58.c: New test.
            * gcc.dg/Wstringop-overflow-59.c: New test.
            * gcc.dg/Wstringop-overflow-60.c: New test.
            * gcc.dg/Wstringop-overflow-61.c: New test.
            * gcc.dg/Wstringop-overflow-62.c: New test.
            * gcc.dg/Wstringop-overflow-63.c: New test.
            * gcc.dg/Wstringop-overflow-64.c: New test.

[Bug middle-end/92940] incorrect offset and size in -Wstringop-overflow for out-of-bounds store into VLA and two offset ranges

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92940

Martin Sebor <msebor at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |11.0
      Known to fail|                            |10.2.0
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED
      Known to work|                            |11.0

--- Comment #4 from Martin Sebor <msebor at gcc dot gnu.org> ---
Resolved by r11-5523 for GCC 11 which prints the following warning and note:

$ gcc -O2 -S pr92940.c
pr92940.c: In function ‘g’:
pr92940.c:13:8: warning: writing 1 byte into a region of size 0
[-Wstringop-overflow=]
   13 |   p[j] = 0;
      |   ~~~~~^~~
pr92940.c:9:8: note: at offset 4 into destination object ‘a’ of size [3, 4]
    9 |   char a[n];
      |        ^