[Bug 27367] New: widl: gcc warns about pointer mismatch when calling pfnFree

http://bugs.winehq.org/show_bug.cgi?id=27367

Summary: widl: gcc warns about pointer mismatch when calling
                    pfnFree
           Product: Wine
           Version: 1.3.21
          Platform: x86-64
        OS/Version: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: tools
        AssignedTo: [e-mail]
        ReportedBy: [e-mail]

Created an attachment (id=34992)
 --> (http://bugs.winehq.org/attachment.cgi?id=34992)
Patch that fixes the warning by adding a cast to void * when calling pfnFree

When compiling latest wine, I have the following warning :

../../tools/widl/widl -I../../../git-wine/dlls/actxprxy -I.
-I../../../git-wine/include -I../../include  -D__WINESRC__ -DWINE_REGISTER_DLL
-DPROXY_DELEGATION  -p -o actxprxy_shobjidl_p.c
../../../git-wine/dlls/actxprxy/actxprxy_shobjidl.idl
../../tools/widl/widl -I../../../git-wine/dlls/actxprxy -I.
-I../../../git-wine/include -I../../include  -D__WINESRC__ -DWINE_REGISTER_DLL
-DPROXY_DELEGATION  -h -o actxprxy_shobjidl.h
../../../git-wine/dlls/actxprxy/actxprxy_shobjidl.idl
gcc -c -I../../../git-wine/dlls/actxprxy -I. -I../../../git-wine/include
-I../../include  -D__WINESRC__ -DWINE_REGISTER_DLL -DPROXY_DELEGATION
-D_REENTRANT -fPIC -Wall -pipe -fno-strict-aliasing
-Wdeclaration-after-statement -Wempty-body -Wstrict-prototypes -Wtype-limits
-Wwrite-strings -Wpointer-arith -Wlogical-op  -g -O2 -U_FORTIFY_SOURCE
-D_FORTIFY_SOURCE=0  -o actxprxy_shobjidl_p.o actxprxy_shobjidl_p.c
actxprxy_shobjidl_p.c: In function ‘__finally_IFileDialog_SetFileTypes_Stub’:
actxprxy_shobjidl_p.c:94496:9: warning: passing argument 1 of
‘__frame->_StubMsg.pfnFree’ discards qualifiers from pointer target type
actxprxy_shobjidl_p.c:94496:9: note: expected ‘void *’ but argument is of type
‘const struct COMDLG_FILTERSPEC *’

The actxprxy_shobjidl_p.c file is generated by widl from include/shobjidl.idl.
I found 3 references for pfnFree in tools/widl/typegen.c so I added a (void *)
cast 3 times with more or less spaces.

It appears the relevant pfnFree is at typegen.c:3778.

I'm attaching a patch that made the warning disappear.
Can someone tell me if this is the right approach ?

Ideally, wine would compile without any warning whatever your compiler or
architecture is.

[Bug 27367] widl: gcc warns about pointer mismatch when calling pfnFree

http://bugs.winehq.org/show_bug.cgi?id=27367

--- Comment #1 from Alexandre Julliard  2011-06-02 06:45:24 CDT ---
Probably a cleaner way would be to not declare it const in the first place.

[Bug 27367] widl: gcc warns about pointer mismatch when calling pfnFree

http://bugs.winehq.org/show_bug.cgi?id=27367

--- Comment #2 from Alex  2011-06-04 07:43:56 CDT ---
You're right but in this case, wine SetFileTypes would not match the Windows
prototype anymore.

See http://msdn.microsoft.com/en-us/library/bb775980%28v=vs.85%29.aspx

Your proposed solution doesn't fix the problem but just this particular case.

I know casts are evil (because they often hide a real issue) but what about
this one ?

We could also simply ignore this warning as it has no real impact and (among
the 45 warnings I have), some are more important (e.g. call_server_func not
implemented for your architecture)

[Bug 27367] widl: gcc warns about pointer mismatch when calling pfnFree

http://bugs.winehq.org/show_bug.cgi?id=27367

--- Comment #3 from Alexandre Julliard  2011-06-04 08:45:43 CDT ---
I'm of course not suggesting to change the idl source, we can't do that. What
I'm saying is that widl shouldn't output the const in the stub, since it's not
const there because we are unmarshalling into it.

[Bug 27367] widl: gcc warns about pointer mismatch when calling pfnFree

http://bugs.winehq.org/show_bug.cgi?id=27367

--- Comment #4 from Alex  2011-06-04 09:05:27 CDT ---
It makes more sense this way.

As you began to clean/improve widl recently, feel free to fix it.

I'm definitely not an expert with widl but I know how to report clear and
useful bugs.

Thanks for the energy you invest in wine : after all, it's the weekend and you
(and probably I) have a life.

[Bug 27367] widl: gcc warns about pointer mismatch when calling pfnFree

http://bugs.winehq.org/show_bug.cgi?id=27367

Alex  changed:

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

--- Comment #5 from Alex  2011-12-16 08:21:06 CST ---
I compiled the latest wine from git and the warning doesn't appear any more.

I also tried to do a git bisect to find the commit which fixed it but git
disallow bisecting with a bad commit older than the good one.

So I'm closing this bug as fixed.

[Bug 27367] widl: gcc warns about pointer mismatch when calling pfnFree

http://bugs.winehq.org/show_bug.cgi?id=27367

Alexandre Julliard  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |CLOSED

--- Comment #6 from Alexandre Julliard  2011-12-16 13:30:41 CST ---
Closing bugs fixed in 1.3.35.