Re: [PATCH 00/11] C++/MinGW patches

Qian Hong
2015-11-09T09:53:06Z

Hi Pedro,

Thanks for the info, I did some tests with your code.

On Wed, Nov 4, 2015 at 6:39 AM, Pedro Alves <palves@redhat.com> wrote:
> So it seems to me that something is wrong with C++ exceptions
> support in the mingw toolchain you used. I suggest trying a simple
> test like:
>
> int
> main ()
> {
> try
> {
> throw 1;
> }
> catch(...)
> {
> }
>
> return 0;
> }
>
> ... to check whether C++ exceptions work at all.

The above test case works for me.
I tried several thing:
1. build the above code with MINGW-w64 g++ from MSYS2, run on MSYS2.
It works on both Windows and Wine.
2. build the above code with MinGW-w64 cross compiler from my Ubuntu,
runs on Wine, works as expected.
3. build the above code with Linux native g++ (i386), runs on Linux,
works as expected.
4. Added customer printf statement to the source code, retest on all
configuration above, and I can confirm all executed code path are the
same.

> One issue to look out for is what flavor of C++ exceptions your mingw
> toolchain uses. There are flavors using dwarf2, others using sjlj. Also, we
> link gdb with -static-libstdc++ -static-libgcc, which may make a difference.

I tried all 4 combination of with/without
-static-libstdc++/-static-libgcc, the test case works for me on
Windows with MinGW-w64 g++ from MSYS2.

MSYS2 g++ has --disable-sjlj-exceptions --with-dwarf2, not sure if it
does matter.

Here is the MinGW-w64 g++ provided by MSYS2:
Using built-in specs.
COLLECT_GCC=E:\msys32\mingw32\bin\g++.exe
COLLECT_LTO_WRAPPER=E:/msys32/mingw32/bin/../lib/gcc/i686-w64-mingw32/5.2.0/lto-wrapper.exe
Target: i686-w64-mingw32
Configured with: ../gcc-5.2.0/configure --prefix=/mingw32
--with-local-prefix=/mingw32/local --build=i686-w64-mingw32
--host=i686-w64-mingw32 --target=i686-w64-mingw32
--with-native-system-header-dir=/mingw32/i686-w64-mingw32/include
--libexecdir=/mingw32/lib
--with-gxx-include-dir=/mingw32/include/c++/5.2.0 --enable-bootstrap
--with-arch=i686 --with-tune=generic
--enable-languages=c,lto,c++,objc,obj-c++,fortran,ada --enable-shared
--enable-static --enable-libatomic --enable-threads=posix
--enable-graphite --enable-fully-dynamic-string
--enable-libstdcxx-time=yes --disable-libstdcxx-pch
--disable-libstdcxx-debug --enable-version-specific-runtime-libs
--disable-isl-version-check --enable-lto --enable-libgomp
--disable-multilib --enable-checking=release --disable-rpath
--disable-win32-registry --disable-nls --disable-werror
--disable-symvers --with-libiconv --with-system-zlib
--with-gmp=/mingw32 --with-mpfr=/mingw32 --with-mpc=/mingw32
--with-isl=/mingw32 --with-pkgversion='Rev4, Built by MSYS2 project'
--with-bugurl=http://sourceforge.net/projects/msys2 --with-gnu-as
--with-gnu-ld --disable-sjlj-exceptions --with-dwarf2
Thread model: posix
gcc version 5.2.0 (Rev4, Built by MSYS2 project)

I've forwarded the question to MSYS2 maintainers in #msys2 (OFTC),
will update once I have more information.

Thanks!

--
Regards,
Qian Hong

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