[Bug 49138] New: winegcc: argc and argv arguments of main() get corrupted

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=49138

Bug ID: 49138
           Summary: winegcc: argc and argv arguments of main() get
                    corrupted
           Product: Wine
           Version: 5.7
          Hardware: x86-64
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: tools
          Assignee: [e-mail]
          Reporter: [e-mail]
      Distribution: ---

I first came across this issue with winelib compilation in Wine 5.7 while I was
working on yabridge, a Wine VST bridge. The issue still persists on the latest
commit in the Wine repository as I'm writing this (commit bf1abba, with the
release of Wine 5.8). I'm not exactly sure what is going on, but the issue can
be reproduced as follows:

#include <iostream>

int main(int argc, char* argv[]) {
        std::cout << "argc = " << argc << std::endl;
        std::cout << "argv[0] = " << argv[0] << std::endl;
    }

If you compile the above (or the C-equivalent) with `wineg++ test.cpp -o test`
and run test.exe, then at least on my system it will always print 70624 as the
value of argc and some uninitialized looking data for argv[0]. This happens
regardless of whether the program receives any command line arguments or not.

Winelib applications compiled with the toolchain that comes with Wine 5.6 can
be
run without problems under Wine 5.7 or 5.8. The winelib compilation issue with
Wine 5.7+ exists on Ubuntu 18.04, Ubuntu 20.04, Arch Linux and Manjaro, both
when using the distro provided packages and when building Wine from source.

[Bug 49138] winegcc: argc and argv arguments of main() get corrupted

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=49138

Zebediah Figura  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |[e-mail]

--- Comment #1 from Zebediah Figura  ---
The calling convention doesn't match anymore, and needs to be explicitly
specified by appending __cdecl. See ed6a5e97e0. It seems undesirable that this
is necessary...

[Bug 49138] winegcc: argc and argv arguments of main() get corrupted

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=49138

--- Comment #2 from Robbert van der Helm  ---
Adding an explicit calling convention does indeed solve the issue for both
yabridge and the example I posted here! I experimented a bit with the WinMain
entry point function before with no success but somehow I never though of
explicitly specifying the __cdecl calling convention on my regular main()
function. Did the default calling convention change somewhere between Wine 5.6
and Wine 5.7?

[Bug 49138] winegcc: argc and argv arguments of main() get corrupted

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=49138

--- Comment #3 from Robbert van der Helm  ---
Now that Wine 6.0 no longer requires __cdecl for Winelib binaries and the
behaviour is back to what it was before Wine 5.7, maybe this ticket can be
closed now.