[Bug 51596] New: Unhandled exception code c0000005 when running any 64-bit Winelib application

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=51596

Bug ID: 51596
           Summary: Unhandled exception code c0000005 when running any
                    64-bit Winelib application
           Product: Wine
           Version: 6.14
          Hardware: x86-64
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: winelib
          Assignee: [e-mail]
          Reporter: [e-mail]
      Distribution: ArchLinux

Somewhere after Wine 6.14, 64-bit Winelib applications are no longer able to
start when Wine is compiled with optimizations. Everything still works just
fine
when setting {C,CXX,CROSSC}FLAGS to "-g -O0", and 32-bit Winelib applications
also still work fine. I haven't tested which exact commit introduced this
issue,
but it at least happens after f63ecaedc72f3580e7016ba71a480025e4d86e99

To reproduce this issue, create a main.cpp file with the following contents and
then compile it with `wineg++ -o main main.cpp -mwindows -m64`:

#include <iostream>

int main() {
        std::cout << "Hello, world!" << std::endl;
    }

Running main.exe with these versions of the latest master branch version of
Wine
Staging (wine-6.14-323-g91494ae6f2e right now) prints the following:

0144:err:seh:NtRaiseException Unhandled exception code c0000005 flags 0
addr 0x7bc2dc17

Doing the same thing with a 32-bit Winelib (i.e. with -m32) works just fine,
and
the 64-bit version also works fine when compiling Wine the following
configuration:

CC='ccache gcc' CXX='ccache g++' CROSSCC='ccache x86_64-w64-mingw32-gcc'
CFLAGS="-g -O0" CXXFLAGS="-g -O0" CROSSCFLAGS="-g -O0" ../configure
--disable-tests --enable-win64

Leaving out those flags brings back the error, so there's likely some kind of
UB
at play here.