[Bug analyzer/111289] New: Unwarranted -Wanalyzer-va-arg-type-mismatch warning

[Bug analyzer/111289] New: Unwarranted -Wanalyzer-va-arg-type-mismatch warning

[bruno at clisp dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111289

            Bug ID: 111289
           Summary: Unwarranted -Wanalyzer-va-arg-type-mismatch warning
           Product: gcc
           Version: 13.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: analyzer
          Assignee: dmalcolm at gcc dot gnu.org
          Reporter: bruno at clisp dot org
  Target Milestone: ---

Created attachment 55842
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=55842&action=edit
test case foo.c

On the attached program, gcc 13.2.0 with analyzer produces a warning:

$ gcc -fanalyzer -O2 -S foo.c
foo.c: In function ‘do_open’:
foo.c:13:10: warning: ‘va_arg’ expected ‘mode_t’ {aka ‘unsigned int’} but
received ‘int’ for variadic argument 1 of ‘arg’ [CWE-686]
[-Wanalyzer-va-arg-type-mismatch]
   13 |   mode_t mode = va_arg (arg, mode_t);
      |          ^~~~
  ‘main’: events 1-2
    |
    |   20 | main ()
    |      | ^~~~
    |      | |
    |      | (1) entry to ‘main’
    |   21 | {
    |   22 |   do_open ("nonexist.ent/", 0600);
    |      |   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    |      |   |
    |      |   (2) calling ‘do_open’ from ‘main’ with 1 variadic argument
    |
    +--> ‘do_open’: events 3-4
           |
           |    8 | do_open (char const *name, ...)
           |      | ^~~~~~~
           |      | |
           |      | (3) entry to ‘do_open’
           |......
           |   13 |   mode_t mode = va_arg (arg, mode_t);
           |      |          ~~~~
           |      |          |
           |      |          (4) ‘va_arg’ expected ‘mode_t’ {aka ‘unsigned
int’} but received ‘int’ for variadic argument 1 of ‘arg’
           |

There is no reason to warn here, because
1) ISO C 99 § 7.15.1.1.(2) says "... the behavior is undefined, except for the
following cases:
— one type is a signed integer type, the other type is the corresponding
unsigned integer type, and the value is representable in both types;
— ..."
Likewise ISO C 23 § 7.16.1.1.(2).
2) The argument that gets passed is an 'int'. The other type, mode_t, is
'unsigned int'. The argument is a constant, and its value 0600 is representable
both as 'int' and as 'unsigned int'.

[Bug analyzer/111289] [13/14 Regression] Unwarranted -Wanalyzer-va-arg-type-mismatch warning

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111289

David Malcolm <dmalcolm at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|Unwarranted                 |[13/14 Regression]
                   |-Wanalyzer-va-arg-type-mism |Unwarranted
                   |atch warning                |-Wanalyzer-va-arg-type-mism
                   |                            |atch warning
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2024-02-15
             Status|UNCONFIRMED                 |NEW

--- Comment #1 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
Thanks for filing this bug report.

Trunk: https://godbolt.org/z/aK9adEYdT
GCC 13.2: https://godbolt.org/z/G1E1o4sbr

The warning was introduced in GCC 13 so can't affect earlier releases

[Bug analyzer/111289] [13/14 Regression] Unwarranted -Wanalyzer-va-arg-type-mismatch warning

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111289

--- Comment #2 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by David Malcolm <dmalcolm@gcc.gnu.org>:

https://gcc.gnu.org/g:5651ad62b08096a155a7e394c7494f5ff1c04f4f

commit r14-9076-g5651ad62b08096a155a7e394c7494f5ff1c04f4f
Author: David Malcolm <dmalcolm@redhat.com>
Date:   Mon Feb 19 18:08:05 2024 -0500

    analyzer: fix -Wanalyzer-va-arg-type-mismatch false +ve on int types
[PR111289]

    gcc/analyzer/ChangeLog:
            PR analyzer/111289
            * varargs.cc (representable_in_integral_type_p): New.
            (va_arg_compatible_types_p): Add "arg_sval" param.  Handle integer
            types.
            (kf_va_arg::impl_call_pre): Pass arg_sval to
            va_arg_compatible_types_p.

    gcc/testsuite/ChangeLog:
            PR analyzer/111289
            * c-c++-common/analyzer/stdarg-pr111289-int.c: New test.
            * c-c++-common/analyzer/stdarg-pr111289-ptr.c: New test.

    Signed-off-by: David Malcolm <dmalcolm@redhat.com>

[Bug analyzer/111289] [13 Regression] Unwarranted -Wanalyzer-va-arg-type-mismatch warning

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111289

David Malcolm <dmalcolm at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[13/14 Regression]          |[13 Regression] Unwarranted
                   |Unwarranted                 |-Wanalyzer-va-arg-type-mism
                   |-Wanalyzer-va-arg-type-mism |atch warning
                   |atch warning                |
             Status|NEW                         |ASSIGNED

--- Comment #3 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
Should be fixed on trunk for gcc 14 by the above patch.
Keeping open to track the backport to gcc 13.

[Bug analyzer/111289] [13 Regression] Unwarranted -Wanalyzer-va-arg-type-mismatch warning

[danglin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111289

John David Anglin <danglin at gcc dot gnu.org> changed:

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

--- Comment #4 from John David Anglin <danglin at gcc dot gnu.org> ---
On hppa64-hp-hpux11.11:

FAIL: c-c++-common/analyzer/stdarg-pr111289-int.c  -std=c++98  (test for
warnings, line 60)
FAIL: c-c++-common/analyzer/stdarg-pr111289-int.c  -std=c++98 (test for excess
errors)
Excess errors:
/home/dave/gnu/gcc/gcc/gcc/testsuite/c-c++-common/analyzer/stdarg-pr111289-int.c:5:22:
error: conflicting declaration 'typedef unsigned int mode_t'
/home/dave/gnu/gcc/gcc/gcc/testsuite/c-c++-common/analyzer/stdarg-pr111289-int.c:17:30:
warning: 'mode_t' {aka 'short unsigned int'} is promoted to 'int' when passed
through '...'

[Bug analyzer/111289] [13 Regression] Unwarranted -Wanalyzer-va-arg-type-mismatch warning

[danglin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111289

--- Comment #5 from John David Anglin <danglin at gcc dot gnu.org> ---
Created attachment 57800
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=57800&action=edit
Patch

Don't include <limits.h> on hpux to avoid conflicting type declarations
for mode_t.   This fixes test on houx.

[Bug analyzer/111289] [13 Regression] Unwarranted -Wanalyzer-va-arg-type-mismatch warning

[bruno at clisp dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111289

--- Comment #6 from Bruno Haible <bruno at clisp dot org> ---
(In reply to John David Anglin from comment #5)
> Don't include <limits.h> on hpux to avoid conflicting type declarations
> for mode_t.   This fixes test on houx.

Why not entirely remove the '#include <limits.h>'? There is nothing in this
file that needs it.

[Bug analyzer/111289] [13 Regression] Unwarranted -Wanalyzer-va-arg-type-mismatch warning

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111289

--- Comment #7 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by John David Anglin <danglin@gcc.gnu.org>:

https://gcc.gnu.org/g:86b0b1bec6790f84b7a56fcef2a0a6c8cd91ffef

commit r14-9714-g86b0b1bec6790f84b7a56fcef2a0a6c8cd91ffef
Author: John David Anglin <danglin@gcc.gnu.org>
Date:   Thu Mar 28 18:32:12 2024 +0000

    Fix failure of c-c++-common/analyzer/stdarg-pr111289-int.c on hpux

    2024-03-28  John David Anglin  <danglin@gcc.gnu.org>

    gcc/testsuite/ChangeLog:

            PR analyzer/111289
            * c-c++-common/analyzer/stdarg-pr111289-int.c: Don't include
            <limits.h>.

[Bug analyzer/111289] [13 Regression] Unwarranted -Wanalyzer-va-arg-type-mismatch warning

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111289

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |13.3

[Bug analyzer/111289] [13 Regression] Unwarranted -Wanalyzer-va-arg-type-mismatch warning

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111289

--- Comment #8 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-13 branch has been updated by David Malcolm
<dmalcolm@gcc.gnu.org>:

https://gcc.gnu.org/g:67d104f3a032ee64bae335269bf1b8434785cc63

commit r13-8755-g67d104f3a032ee64bae335269bf1b8434785cc63
Author: David Malcolm <dmalcolm@redhat.com>
Date:   Thu May 9 13:09:31 2024 -0400

    analyzer: fix -Wanalyzer-va-arg-type-mismatch false +ve on int types
[PR111289]

    Backported from commit r14-9076-g5651ad62b08096 (moving new tests from
    c-c++-common to gcc.dg).

    gcc/analyzer/ChangeLog:
            PR analyzer/111289
            * varargs.cc (representable_in_integral_type_p): New.
            (va_arg_compatible_types_p): Add "arg_sval" param.  Handle integer
            types.
            (kf_va_arg::impl_call_pre): Pass arg_sval to
            va_arg_compatible_types_p.

    gcc/testsuite/ChangeLog:
            PR analyzer/111289
            * gcc.dg/analyzer/stdarg-pr111289-int.c: New test.
            * gcc.dg/analyzer/stdarg-pr111289-ptr.c: New test.

    Signed-off-by: David Malcolm <dmalcolm@redhat.com>

[Bug analyzer/111289] Unwarranted -Wanalyzer-va-arg-type-mismatch warning

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111289

David Malcolm <dmalcolm at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[13 Regression] Unwarranted |Unwarranted
                   |-Wanalyzer-va-arg-type-mism |-Wanalyzer-va-arg-type-mism
                   |atch warning                |atch warning
         Resolution|---                         |FIXED
             Status|ASSIGNED                    |RESOLVED

--- Comment #9 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
Should be fixed for GCC 13 (for the upcoming GCC 13.3) by the above patch.