[Bug c++/57111] New: Core dump - invalid pointer detected after std::unique_ptr

[Bug c++/57111] New: Core dump - invalid pointer detected after std::unique_ptr

[jb.1234abcd at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57111

             Bug #: 57111
           Summary: Core dump - invalid pointer detected after
                    std::unique_ptr
    Classification: Unclassified
           Product: gcc
           Version: 4.7.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: jb.1234abcd@gmail.com


$ cat uniqueptr.cpp
#include <iostream>
#include <memory>

int main () {
  int arr[]={1,2};
  std::unique_ptr<int[]> up(arr);
  std::cout << up[0];
  return 0;
}
$ g++ -std=c++11 -Wall -o uniqueptr uniqueptr.cpp 
$ ./uniqueptr 
*** glibc detected *** ./uniqueptr: free(): invalid pointer: 0xbfe35788 ***
======= Backtrace: =========
/lib/libc.so.6[0x4ce44ff9]
/lib/libstdc++.so.6(_ZdlPv+0x20)[0x4d414500]
/lib/libstdc++.so.6(_ZdaPv+0x1c)[0x4d41455c]
./uniqueptr[0x80489fd]
./uniqueptr[0x8048966]
./uniqueptr[0x8048765]
/lib/libc.so.6(__libc_start_main+0xf5)[0x4cde8865]
./uniqueptr[0x8048611]
======= Memory map: ========
08048000-0804a000 r-xp 00000000 08:09 1963079    /home/jb/prog-c++/uniqueptr
0804a000-0804b000 r--p 00001000 08:09 1963079    /home/jb/prog-c++/uniqueptr
0804b000-0804c000 rw-p 00002000 08:09 1963079    /home/jb/prog-c++/uniqueptr
08dbf000-08de0000 rw-p 00000000 00:00 0          [heap]
4cdac000-4cdcb000 r-xp 00000000 08:09 655817     /usr/lib/ld-2.16.so
4cdcb000-4cdcc000 r--p 0001e000 08:09 655817     /usr/lib/ld-2.16.so
4cdcc000-4cdcd000 rw-p 0001f000 08:09 655817     /usr/lib/ld-2.16.so
4cdcf000-4cf7f000 r-xp 00000000 08:09 659071     /usr/lib/libc-2.16.so
4cf7f000-4cf81000 r--p 001b0000 08:09 659071     /usr/lib/libc-2.16.so
4cf81000-4cf82000 rw-p 001b2000 08:09 659071     /usr/lib/libc-2.16.so
4cf82000-4cf85000 rw-p 00000000 00:00 0 
4cfce000-4d00c000 r-xp 00000000 08:09 664509     /usr/lib/libm-2.16.so
4d00c000-4d00d000 r--p 0003d000 08:09 664509     /usr/lib/libm-2.16.so
4d00d000-4d00e000 rw-p 0003e000 08:09 664509     /usr/lib/libm-2.16.so
4d010000-4d02c000 r-xp 00000000 08:09 664696    
/usr/lib/libgcc_s-4.7.2-20121109.so.1
4d02c000-4d02d000 r--p 0001b000 08:09 664696    
/usr/lib/libgcc_s-4.7.2-20121109.so.1
4d02d000-4d02e000 rw-p 0001c000 08:09 664696    
/usr/lib/libgcc_s-4.7.2-20121109.so.1
4d3c9000-4d4a9000 r-xp 00000000 08:09 664705     /usr/lib/libstdc++.so.6.0.17
4d4a9000-4d4ad000 r--p 000df000 08:09 664705     /usr/lib/libstdc++.so.6.0.17
4d4ad000-4d4af000 rw-p 000e3000 08:09 664705     /usr/lib/libstdc++.so.6.0.17
4d4af000-4d4b5000 rw-p 00000000 00:00 0 
b7777000-b777a000 rw-p 00000000 00:00 0 
b778b000-b778e000 rw-p 00000000 00:00 0 
b778e000-b778f000 r-xp 00000000 00:00 0          [vdso]
bfe17000-bfe38000 rw-p 00000000 00:00 0          [stack]
1Aborted (core dumped)
$ 

Packages:
gcc-c++-4.7.2-8.fc18.i686
glibc-2.16-30.fc18.i686
libstdc++-4.7.2-8.fc18.i686

[Bug c++/57111] Core dump - invalid pointer detected after std::unique_ptr

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57111

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> 2013-04-29 12:57:36 UTC ---
That's not how you use unique_ptr.

[Bug c++/57111] Core dump - invalid pointer detected after std::unique_ptr

[jb.1234abcd at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57111

--- Comment #2 from jb <jb.1234abcd at gmail dot com> 2013-04-29 14:04:38 UTC ---
(In reply to comment #1)
> That's not how you use unique_ptr.

That's besides the point when you get a dump.
If the proper use of unique_ptr with array is:
unique_ptr<int[]> up(new int[4]); //array version of unique_ptr
then the compiler should give a warning on "improper use", do not you think ?

[Bug c++/57111] Core dump - invalid pointer detected after std::unique_ptr

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57111

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> 2013-04-29 14:09:46 UTC ---
(In reply to comment #2)
> (In reply to comment #1)
> > That's not how you use unique_ptr.
> 
> That's besides the point when you get a dump.

No, it's entirely the point, you get a coredump because your program has
undefined behaviour when it attempts to delete a stack variable.

> If the proper use of unique_ptr with array is:
> unique_ptr<int[]> up(new int[4]); //array version of unique_ptr
> then the compiler should give a warning on "improper use", do not you think ?

The compiler can't warn about everything.  Sometimes you just have to meet the
requirements of the API you're using and not to stupid things.

[Bug c++/57111] Core dump - invalid pointer detected after std::unique_ptr

[glisse at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57111

--- Comment #4 from Marc Glisse <glisse at gcc dot gnu.org> 2013-04-30 18:37:41 UTC ---
gcc has -Wfree-nonheap-object, which works for free but not for delete or
delete[]. Extending it to these functions seems like a reasonable RFE.

[Bug c++/57111] Core dump - invalid pointer detected after std::unique_ptr

[jb.1234abcd at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57111

--- Comment #5 from jb <jb.1234abcd at gmail dot com> 2013-04-30 21:57:00 UTC ---
(In reply to comment #4)
> gcc has -Wfree-nonheap-object, which works for free but not for delete or
> delete[]. Extending it to these functions seems like a reasonable RFE.

I agree with your suggestion.

gcc(1)
       -Wno-free-nonheap-object
           Do not warn when attempting to free an object that was not
           allocated on the heap.

The above is a non-default option.

$ cat free-test.c
#include <stdlib.h>

int main () {
  int arr[] = {1,2};
  int * p = arr;
  free(p);
  return 0;
}

$ gcc -Wall -o free-test free-test.c 
$ ./free-test                      
Segmentation fault (core dumped)

$ gcc -Wall -Wfree-nonheap-object -o free-test free-test.c
$ ./free-test
Segmentation fault (core dumped)

$ gcc -Wall -Wno-free-nonheap-object -o free-test free-test.c
$ ./free-test
Segmentation fault (core dumped)
$

It seems to me that the option "free-nonheap-object" does not work in gcc.

[Bug c++/57111] Core dump - invalid pointer detected after std::unique_ptr

[glisse at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57111

--- Comment #6 from Marc Glisse <glisse at gcc dot gnu.org> 2013-04-30 22:07:02 UTC ---
(In reply to comment #5)
> It seems to me that the option "free-nonheap-object" does not work in gcc.

You need to add -O2 (maybe -O1 is enough, sometimes you need -O3), otherwise
gcc does not propagate the information of what p is all the way to free.

[Bug c++/57111] Core dump - invalid pointer detected after std::unique_ptr

[jb.1234abcd at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57111

--- Comment #7 from jb <jb.1234abcd at gmail dot com> 2013-04-30 22:22:44 UTC ---
(In reply to comment #6)
> (In reply to comment #5)
> > It seems to me that the option "free-nonheap-object" does not work in gcc.
> 
> You need to add -O2 (maybe -O1 is enough, sometimes you need -O3), otherwise
> gcc does not propagate the information of what p is all the way to free.

OK, that worked.

$ gcc -O1 -Wall -o free-test free-test.c 
free-test.c: In function ‘main’:
free-test.c:6:7: warning: attempt to free a non-heap object ‘arr’
[-Wfree-nonheap-object]
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Subject: [Bug c++/57111] Core dump - invalid pointer detected after std::unique_ptr
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http://gcc.gnu.org/bugzilla/show_bug.cgi?idW111

jb <jb.1234abcd at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |VERIFIED

--- Comment #8 from jb <jb.1234abcd at gmail dot com> 2013-04-30 22:50:12 UTC ---
Please reopen this bug report.
The RFE will make this feature consistent across gcc and g++.

[Bug c++/57111] Generalize -Wfree-nonheap-object to delete

[glisse at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57111

Marc Glisse <glisse at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |diagnostic
             Status|VERIFIED                    |UNCONFIRMED
         Resolution|INVALID                     |
            Summary|Core dump - invalid pointer |Generalize
                   |detected after              |-Wfree-nonheap-object to
                   |std::unique_ptr             |delete
           Severity|normal                      |enhancement

--- Comment #9 from Marc Glisse <glisse at gcc dot gnu.org> 2013-04-30 22:58:53 UTC ---
"verified" isn't the right status, you are hoping for someone to set it to NEW,
and leaving it at unconfirmed is the way to say that.

[Bug c++/57111] Generalize -Wfree-nonheap-object to delete

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57111

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2013-04-30
     Ever Confirmed|0                           |1

--- Comment #10 from Jonathan Wakely <redi at gcc dot gnu.org> 2013-04-30 23:01:11 UTC ---
OK, confirmed as a diagnostic enhancement

[Bug c++/57111] Generalize -Wfree-nonheap-object to delete

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57111

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |patch
           Assignee|unassigned at gcc dot gnu.org      |msebor at gcc dot gnu.org
                 CC|                            |msebor at gcc dot gnu.org
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=90629

--- Comment #11 from Martin Sebor <msebor at gcc dot gnu.org> ---
The patch I submitted for pr90629 implements this enhancement:
https://gcc.gnu.org/pipermail/gcc-patches/2020-November/557987.html

It detects the bug in the test case in comment #0 but only with optimization
(to see through inlined calls) and with -Wsystem-headers.  Just like all late
warnings to date, -Wfree-nonheap-object isn't without false positives.  pr54202
is one that even the exceedingly simplistic -Wfree-nonheap-object is
susceptible to.  The patch above doesn't change things.

In file included from
/build/gcc-trunk/x86_64-pc-linux-gnu/libstdc++-v3/include/memory:76,
                 from t.C:2:
In member function ‘typename std::enable_if<std::is_convertible<_Up (*)[], _Tp
(*)[]>::value>::type std::default_delete<_Tp []>::operator()(_Up*) const [with
_Up = int; _Tp = int]’,
    inlined from ‘std::unique_ptr<_Tp [], _Dp>::~unique_ptr() [with _Tp = int;
_Dp = std::default_delete<int []>]’ at
/build/gcc-trunk/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/unique_ptr.h:612:17,
    inlined from ‘int main()’ at t.C:6:32:
/build/gcc-trunk/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/unique_ptr.h:120:11:
warning: ‘void operator delete [](void*)’ called on unallocated object ‘arr’
[-Wfree-nonheap-object]
  120 |           delete [] __ptr;
      |           ^~~~~~~~~~~~~~~
t.C: In function ‘int main()’:
t.C:5:7: note: declared here
    5 |   int arr[]={1,2};
      |       ^~~

[Bug c++/57111] Generalize -Wfree-nonheap-object to delete

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57111

--- Comment #12 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Martin Sebor from comment #11)
> It detects the bug in the test case in comment #0 but only with optimization
> (to see through inlined calls) and with -Wsystem-headers.

This seems like a warning that should not be suppressed in system headers.

Diagnostic pragmas could be added to system headers to suppress false
positives.

[Bug c++/57111] Generalize -Wfree-nonheap-object to delete

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57111

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED

--- Comment #13 from Martin Sebor <msebor at gcc dot gnu.org> ---
(In reply to Jonathan Wakely from comment #12)
> (In reply to Martin Sebor from comment #11)
> > It detects the bug in the test case in comment #0 but only with optimization
> > (to see through inlined calls) and with -Wsystem-headers.
> 
> This seems like a warning that should not be suppressed in system headers.
> 
> Diagnostic pragmas could be added to system headers to suppress false
> positives.

I agree.  I thought it was due to an omission on my part but after checking I
see that the code does jump through all the necessary hoops to trigger even in
system headers, so it's a bug that it doesn't.    Let me see what's going on.

[Bug c++/57111] Generalize -Wfree-nonheap-object to delete

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57111

--- Comment #14 from Martin Sebor <msebor at gcc dot gnu.org> ---
The following enables the warning for the test case reported in comment #0 (and
all libstdc++ code):
https://gcc.gnu.org/pipermail/gcc-patches/2020-December/561378.html

[Bug c++/57111] Generalize -Wfree-nonheap-object to delete

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57111

--- Comment #15 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:fe7f75cf16783589eedbab597e6d0b8d35d7e470

commit r11-6028-gfe7f75cf16783589eedbab597e6d0b8d35d7e470
Author: Martin Sebor <msebor@redhat.com>
Date:   Mon Dec 14 13:30:00 2020 -0700

    Correct/improve maybe_emit_free_warning (PR middle-end/98166, PR c++/57111,
PR middle-end/98160).

    Resolves:
    PR middle-end/98166 - bogus -Wmismatched-dealloc on user-defined allocator
and inlining
    PR c++/57111 - 57111 - Generalize -Wfree-nonheap-object to delete
    PR middle-end/98160 - ICE in default_tree_printer at
gcc/tree-diagnostic.c:270

    gcc/ChangeLog:

            PR middle-end/98166
            PR c++/57111
            PR middle-end/98160
            * builtins.c (check_access): Call tree_inlined_location
            fndecl_alloc_p): Handle BUILT_IN_ALIGNED_ALLOC and
            BUILT_IN_GOMP_ALLOC.
            call_dealloc_p): Remove unused function.
            (new_delete_mismatch_p): Call valid_new_delete_pair_p and rework.
            (matching_alloc_calls_p): Handle built-in deallocation functions.
            (warn_dealloc_offset): Corrct the handling of user-defined
operators
            delete.
            (maybe_emit_free_warning): Avoid assuming expression is a decl.
            Simplify.
            * doc/extend.texi (attribute malloc): Update.
            * tree-ssa-dce.c (valid_new_delete_pair_p): Factor code out into
            valid_new_delete_pair_p in tree.c.
            * tree.c (tree_inlined_location): Define new function.
            (valid_new_delete_pair_p): Define.
            * tree.h (tree_inlined_location): Declare.
            (valid_new_delete_pair_p): Declare.

    gcc/c-family/ChangeLog:

            PR middle-end/98166
            PR c++/57111
            PR middle-end/98160
            * c-attribs.c (maybe_add_noinline): New function.
            (handle_malloc_attribute): Call it.  Use ATTR_FLAG_INTERNAL.
            Implicitly add attribute noinline to functions not declared inline
            and warn on those.

    libstdc++-v3/ChangeLog:
            * testsuite/ext/vstring/requirements/exception/basic.cc: Suppress
            a false positive warning.
            *
testsuite/ext/vstring/requirements/exception/propagation_consistent.cc:
              Same.

    gcc/testsuite/ChangeLog:

            PR middle-end/98166
            PR c++/57111
            PR middle-end/98160
            * g++.dg/warn/Wmismatched-dealloc-2.C: Adjust test of expected
warning.
            * g++.dg/warn/Wmismatched-new-delete.C: Same.
            * gcc.dg/Wmismatched-dealloc.c: Same.
            * c-c++-common/Wfree-nonheap-object-2.c: New test.
            * c-c++-common/Wfree-nonheap-object-3.c: New test.
            * c-c++-common/Wfree-nonheap-object.c: New test.
            * c-c++-common/Wmismatched-dealloc.c: New test.
            * g++.dg/warn/Wfree-nonheap-object-3.C: New test.
            * g++.dg/warn/Wfree-nonheap-object-4.C: New test.
            * g++.dg/warn/Wmismatched-dealloc-2.C: New test.
            * g++.dg/warn/Wmismatched-new-delete-2.C: New test.
            * g++.dg/warn/Wmismatched-new-delete.C: New test.
            * gcc.dg/Wmismatched-dealloc-2.c: New test.
            * gcc.dg/Wmismatched-dealloc-3.c: New test.
            * gcc.dg/Wmismatched-dealloc.c: New test.

[Bug c++/57111] Generalize -Wfree-nonheap-object to delete

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57111

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=54202
             Status|ASSIGNED                    |RESOLVED
   Target Milestone|---                         |11.0
         Resolution|---                         |FIXED

--- Comment #16 from Martin Sebor <msebor at gcc dot gnu.org> ---
Done for GCC 11, including issuing warnings for system headers.  As I
mentioned, the warning is not free of false positives (e.g., pr54202).

[Bug c++/57111] Generalize -Wfree-nonheap-object to delete

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57111

--- Comment #17 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by David Edelsohn <dje@gcc.gnu.org>:

https://gcc.gnu.org/g:4a1d7f7e203d0ec4b9d67ea6fc9b84bee1e211d3

commit r11-6573-g4a1d7f7e203d0ec4b9d67ea6fc9b84bee1e211d3
Author: David Edelsohn <dje.gcc@gmail.com>
Date:   Sun Jan 10 18:10:34 2021 -0500

    libstdc++: Suppress more vstring testsuite warnings. [PR 98613]

        PR c++/57111 - 57111 - Generalize -Wfree-nonheap-object to delete

    can create false positive warnings for vstring _S_empty_rep.

    This patch prunes the excess false positive warnings from two more
    testcases.

    libstdc++-v3/ChangeLog:

            PR libstdc++/98613
            * testsuite/ext/vstring/cons/moveable.cc: Suppress false positive
            warning.
            * testsuite/ext/vstring/modifiers/assign/move_assign.cc: Same.

[Bug c++/57111] Generalize -Wfree-nonheap-object to delete

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57111

--- Comment #18 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Thomas Schwinge <tschwinge@gcc.gnu.org>:

https://gcc.gnu.org/g:9c03391ba447ff86038d6a34c90ae737c3915b5f

commit r14-1805-g9c03391ba447ff86038d6a34c90ae737c3915b5f
Author: Thomas Schwinge <thomas@codesourcery.com>
Date:   Wed Jun 7 16:24:26 2023 +0200

    Tighten 'dg-warning' alternatives in
'c-c++-common/Wfree-nonheap-object{,-2,-3}.c'

    ..., added in commit fe7f75cf16783589eedbab597e6d0b8d35d7e470
    "Correct/improve maybe_emit_free_warning (PR middle-end/98166, PR
c++/57111, PR middle-end/98160)".

    These use alternatives like, for example, "AB|CDE|FG", but what really
must've
    been meant is "A(B|C)D(E|F)G".  The former variant also does "work": it
matches
    any of "AB", or "CDE", or "FG", which are components of the latter variant.
    (That means, the former variant matches too loosely.)

            gcc/testsuite/
            * c-c++-common/Wfree-nonheap-object-2.c: Tighten 'dg-warning'
            alternatives.
            * c-c++-common/Wfree-nonheap-object-3.c: Likewise.
            * c-c++-common/Wfree-nonheap-object.c: Likewise.

[Bug c++/57111] Generalize -Wfree-nonheap-object to delete

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57111

--- Comment #19 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Thomas Schwinge <tschwinge@gcc.gnu.org>:

https://gcc.gnu.org/g:df071fbd467f0cb3711119ef41d74792fc5e6c8c

commit r14-1838-gdf071fbd467f0cb3711119ef41d74792fc5e6c8c
Author: Thomas Schwinge <thomas@codesourcery.com>
Date:   Wed Jun 7 17:12:01 2023 +0200

    Fix 'dg-warning' in 'c-c++-common/Wfree-nonheap-object-3.c' for C++

        [...]/c-c++-common/Wfree-nonheap-object-3.c:57:24: warning: 'malloc
(dealloc_float)' attribute ignored with deallocation functions declared
'inline' [-Wattributes]
        [...]/c-c++-common/Wfree-nonheap-object-3.c:51:1: note: deallocation
function declared here
        [...]/c-c++-common/Wfree-nonheap-object-3.c: In function 'void
test_nowarn_int(int)':
        [...]/c-c++-common/Wfree-nonheap-object-3.c:25:20: warning: 'void
__builtin_free(void*)' called on pointer 'p' with nonzero offset 4
[-Wfree-nonheap-object]
        [...]/c-c++-common/Wfree-nonheap-object-3.c:24:24: note: returned from
'int* alloc_int(int)'
        [...]/c-c++-common/Wfree-nonheap-object-3.c: In function 'void
test_nowarn_long(int)':
        [...]/c-c++-common/Wfree-nonheap-object-3.c:45:18: warning: 'void
dealloc_long(long int*)' called on pointer '<unknown>' with nonzero offset 8
[-Wfree-nonheap-object]
        [...]/c-c++-common/Wfree-nonheap-object-3.c:44:26: note: returned from
'long int* alloc_long(int)'
        In function 'void dealloc_float(float*)',
            inlined from 'void test_nowarn_float(int)' at
[...]/c-c++-common/Wfree-nonheap-object-3.c:68:19:
        [...]/c-c++-common/Wfree-nonheap-object-3.c:53:18: warning: 'void
__builtin_free(void*)' called on pointer '<unknown>' with nonzero offset 8
[-Wfree-nonheap-object]
        [...]/c-c++-common/Wfree-nonheap-object-3.c: In function 'void
test_nowarn_float(int)':
        [...]/c-c++-common/Wfree-nonheap-object-3.c:67:28: note: returned from
'float* alloc_float(int)'
        PASS: c-c++-common/Wfree-nonheap-object-3.c  -std=gnu++98  (test for
warnings, line 25)
        FAIL: c-c++-common/Wfree-nonheap-object-3.c  -std=gnu++98  (test for
warnings, line 45)
        PASS: c-c++-common/Wfree-nonheap-object-3.c  -std=gnu++98  (test for
warnings, line 51)
        PASS: c-c++-common/Wfree-nonheap-object-3.c  -std=gnu++98  (test for
warnings, line 53)
        PASS: c-c++-common/Wfree-nonheap-object-3.c  -std=gnu++98  (test for
warnings, line 57)
        FAIL: c-c++-common/Wfree-nonheap-object-3.c  -std=gnu++98 (test for
excess errors)
        Excess errors:
        [...]/c-c++-common/Wfree-nonheap-object-3.c:45:18: warning: 'void
dealloc_long(long int*)' called on pointer '<unknown>' with nonzero offset 8
[-Wfree-nonheap-object]

    ..., that is: decorated 'void dealloc_long(long int*)' instead of plain
    'dealloc_long' -- similar to how all the other 'dg-warning's allow for the
    decorated function signature in addition to the plain one.

    This issue was latent since the test case was added in
    commit fe7f75cf16783589eedbab597e6d0b8d35d7e470
    "Correct/improve maybe_emit_free_warning (PR middle-end/98166, PR
c++/57111, PR middle-end/98160)",
    and was finally exposed by my recent
    commit 9c03391ba447ff86038d6a34c90ae737c3915b5f
    "Tighten 'dg-warning' alternatives in
'c-c++-common/Wfree-nonheap-object{,-2,-3}.c'".

            gcc/testsuite/
            * c-c++-common/Wfree-nonheap-object-3.c: Fix 'dg-warning' for C++.