No output files on 4.6/Cygwin

No output files on 4.6/Cygwin

[Piotr Wyderski]

I have a problem with recent builds of GCC4.6 (trunk)
on Cygwin 1.7. The compiler itself builds correctly, but
when I run it on even the simplest input, e.g.

   gcc in.c -o a.exe

with in.c = int main() {}, no executable file is created.
No oputput is created even with the -S and -E options.

The same used to happen with GCC 4.5 experimental
in its early development days, but later started to work
again. Is it a known issue of GCC or Cygwin? Has
anyone managed to get a working 4.6 build on Cygwin?

Best regards,
Piotr Wyderski

Re: No output files on 4.6/Cygwin

[Wojciech Meyer]

On Wed, Jun 9, 2010 at 11:51 AM, Piotr Wyderski
<piotr.wyderski@gmail.com> wrote:
> I have a problem with recent builds of GCC4.6 (trunk)
> on Cygwin 1.7. The compiler itself builds correctly, but
> when I run it on even the simplest input, e.g.
>
>   gcc in.c -o a.exe
>
> with in.c = int main() {}, no executable file is created.
> No oputput is created even with the -S and -E options.

Maybe a mismatched cygwin1.dll. Do you have the right version of
cygwin1.dll on path? e.g the one against which gcc was compiled?.
Cygwin fails silently to execute the image in case of a mismatched
dll.


>
> Best regards,
> Piotr Wyderski
>

Wojciech

Re: No output files on 4.6/Cygwin

[Piotr Wyderski]

Wojciech Meyer wrote:

> Maybe a mismatched cygwin1.dll. Do you have the right version of
> cygwin1.dll on path? e.g the one against which gcc was compiled?.
> Cygwin fails silently to execute the image in case of a mismatched
> dll.

I am not 100% sure that my Cygwin installation is OK, as
it has been upgraded from 1.5 without uninstalling the latter
(i.e. I wiped it out using a mere rm -rf), but the image itself works:

$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/opt/gcc-trunk/libexec/gcc/i686-pc-cygwin/4.6.0/lto-wrapper.exe
Target: i686-pc-cygwin
Configured with: ../configure --prefix=/opt/gcc-trunk -v
--enable-bootstrap --enable-version-specific-runtime-libs --ena
ble-shared --enable-shared-libgcc --with-gnu-ld --with-gnu-as
--enable-dwarf2-exceptions --disable-symvers --disable-nls
 --with-arch=core2 --with-tune=generic --enable-threads=posix
--enable-languages=c,c++ AM_CXXFLAGS=-w
Thread model: posix
gcc version 4.6.0 20100607 (experimental) (GCC)

Best regards
Piotr Wyderski

Re: No output files on 4.6/Cygwin

[Dave Korn]

On 09/06/2010 11:51, Piotr Wyderski wrote:
> I have a problem with recent builds of GCC4.6 (trunk)
> on Cygwin 1.7. The compiler itself builds correctly, but
> when I run it on even the simplest input, e.g.
> 
>    gcc in.c -o a.exe
> 
> with in.c = int main() {}, no executable file is created.
> No oputput is created even with the -S and -E options.
> 
> The same used to happen with GCC 4.5 experimental
> in its early development days, but later started to work
> again. Is it a known issue of GCC or Cygwin? Has
> anyone managed to get a working 4.6 build on Cygwin?

  Yeh, I posted testresults just a little while ago(*).  Are you sure you're
picking up the newest version of cyggcc_s-1.dll (and all the other language
runtimes) that got built with the compiler, rather than the standard system
one(s)?  You did a full "make install" and put the new $prefix/bin (if not
using the standard prefix) at the head of your PATH?

    cheers,
      DaveK
-- 
(*) - http://gcc.gnu.org/ml/gcc-testresults/2010-05/msg02996.html

Re: No output files on 4.6/Cygwin

[Dave Korn]

On 09/06/2010 17:10, Dave Korn wrote:

  Oh, and an afterthought:

> On 09/06/2010 11:51, Piotr Wyderski wrote:
>> I have a problem with recent builds of GCC4.6 (trunk)
>> on Cygwin 1.7. The compiler itself builds correctly, but
>> when I run it on even the simplest input, e.g.
>>
>>    gcc in.c -o a.exe
>>
>> with in.c = int main() {}, no executable file is created.
>> No oputput is created even with the -S and -E options.
>>
>> The same used to happen with GCC 4.5 experimental
>> in its early development days, but later started to work
>> again. Is it a known issue of GCC or Cygwin? Has
>> anyone managed to get a working 4.6 build on Cygwin?

  Wasn't it last time because you didn't have "--disable-sjlj-exceptions" in
your configure command and so you ended up with sjlj-based DLLs that didn't
play nicely with the Cygwin distro's DW2-based ones?  Sorry, that setting
still isn't defaulted on for Cygwin targets yet; it should be, and I'll make a
note to fix it.

    cheers,
      DaveK

Re: No output files on 4.6/Cygwin

[Piotr Wyderski]

Dave,

> Are you sure you're picking up the newest version of cyggcc_s-1.dll
> (and all the other language runtimes) that got built with the compiler,
> rather than the standard system one(s)?

How can I check that?

> You did a full "make install" and put the new $prefix/bin (if not
> using the standard prefix) at the head of your PATH?

Yes: export PATH=/opt/gcc-trunk/bin/:$PATH

> Wasn't it last time because you didn't have "--disable-sjlj-exceptions" in
> your configure command and so you ended up with sjlj-based DLLs that didn't
> play nicely with the Cygwin distro's DW2-based ones?

Yes, then it was the case. But doesn't my

    --enable-dwarf2-exceptions

already imply --disable-sjlj-exceptions? It works with gcc-4.5.

I've just updated my repo and will schedule a nightly build
of trunk with configure settings taken from the bundled gcc4
compiler from Cygwin pack in order to see what will happen.

    Best regards
    Piotr Wyderski

Re: No output files on 4.6/Cygwin

[Dave Korn]

On 09/06/2010 17:31, Piotr Wyderski wrote:

>> Are you sure you're picking up the newest version of cyggcc_s-1.dll
>> (and all the other language runtimes) that got built with the compiler,
>> rather than the standard system one(s)?
> 
> How can I check that?

  Well, verifying your path is correct should be sufficient.

>> You did a full "make install" and put the new $prefix/bin (if not
>> using the standard prefix) at the head of your PATH?
> 
> Yes: export PATH=/opt/gcc-trunk/bin/:$PATH

  That should be fine then.

>> Wasn't it last time because you didn't have "--disable-sjlj-exceptions" in
>> your configure command and so you ended up with sjlj-based DLLs that didn't
>> play nicely with the Cygwin distro's DW2-based ones?
> 
> Yes, then it was the case. But doesn't my
> 
>     --enable-dwarf2-exceptions
> 
> already imply --disable-sjlj-exceptions? It works with gcc-4.5.

  It does?  I've never been aware of any such option; as far as I know, you
have to disable sjlj exceptions, and there's no configure option to positively
enable dw2 ones.

> I've just updated my repo and will schedule a nightly build
> of trunk with configure settings taken from the bundled gcc4
> compiler from Cygwin pack in order to see what will happen.

  That's the simplest way to guarantee compatibility.

    cheers,
      DaveK

Re: No output files on 4.6/Cygwin

[Piotr Wyderski]

Dave Korn wrote:

>> I've just updated my repo and will schedule a nightly build
>> of trunk with configure settings taken from the bundled gcc4
>> compiler from Cygwin pack in order to see what will happen.
>
>  That's the simplest way to guarantee compatibility.

And now the compiler works correctly, so it is tempting
to assume that the problem was related to SJLJ exceptions,
as you conjectured. Thanks!

Best regards
Piotr Wyderski