llvm dev - Mar 2020 - Exceptions on Windows & MSVC

At Microsoft we open sourced some of our compiler tests for exception
handling on github.
https://github.com/microsoft/compiler-tests

We are looking into what it would take to get these to work with clang-cl.
I’m planning to share a design document on the mailing list soon.

Aaron
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20191111/98e16934/attachment.html>

Good to hear. I re-ran the C++ EH tests locally a few months ago with
clang-cl. Most of the tests passed, but some failed. For the ones that
failed, it wasn't immediately clear if it was an EH bug or not. It seemed
like clang was doing more copy elision than MSVC, and that accounted for
most of the variation. It would be good to get to the bottom of it and be
certain, though. In the end it runs fast enough that we could run it
continuously.

On Mon, Nov 11, 2019 at 2:03 PM Aaron Smith via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> At Microsoft we open sourced some of our compiler tests for exception
> handling on github.
> https://github.com/microsoft/compiler-tests
>
> We are looking into what it would take to get these to work with clang-cl.
> I’m planning to share a design document on the mailing list soon.
>
> Aaron
>
>
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20191111/f2c6a9e7/attachment.html>

I tried compiling the source files under “SEH” with the latest official version
of Clang-Cl and Visual Studio 2015. Compiling:
seh0015.c
seh0017.c
seh0035.c
seh0034.c
seh0036.c
seh0041.c
seh0043.c
seh0042.c
seh0049.c
seh0048.c
seh0050.c
xcpt4u.c

Will crash the compiler with “clang frontend command failed due to signal (use
-v to see invocation)” and a stack dump.
Am I the only one having that issue?

From: llvm-dev <llvm-dev-bounces at lists.llvm.org> On Behalf Of Aaron
Smith via llvm-dev
Sent: 11 November 2019 23:03
To: llvm-dev at lists.llvm.org
Subject: [llvm-dev] Exceptions on Windows & MSVC

At Microsoft we open sourced some of our compiler tests for exception handling
on github.
https://github.com/microsoft/compiler-tests

We are looking into what it would take to get these to work with clang-cl. I’m
planning to share a design document on the mailing list soon.

Aaron


Als GmbH eingetragen im Handelsregister Bad Homburg v.d.H. HRB 9816, USt.ID-Nr.
DE 114 165 789 Geschäftsführer: Dr. Hiroshi Nakamura, Dr. Robert Plank, Markus
Bode, Heiko Lampert, Takashi Nagano, Takeshi Fukushima. Junichi Tajika
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20191113/4cd29813/attachment.html>

Thank you for this Aaron!

In our company we rely heavily on the compatibility between Clang-Cl and the
Visual Studio compiler, lately we encountered big problems with the handling of
SEH exceptions in our code, so running those tests helped us. (Sadly we can’t
move to the Visual Studio compiler)

However, maybe it helps someone if I share the results from running those tests…
I imported all of the tests into separated projects, compiling them with the
same settings, with MSVC (v141) and Clang (9), then I compared the output. The
compiler settings for all those projects were:
/permissive- /GS /GL /W3 /Gy /Zc:wchar_t /Gm- /Ox /Ob2 /sdl /Zc:inline
/fp:precise /D "_MBCS" /errorReport:prompt /GF- /WX- /Zc:forScope /Gd
/Oy /Oi /MD /FC /EHsc /nologo /Ot /diagnostics:classic

The MSVC compiler only failed the following test:
EH:
ihateeh.cxx

Clang however failed multiple tests:
EH:
ihateeh.cxx

SEH:
seh0007.c (-> Test failed; The access violation was optimized away, leading
to a random result; – forcing the access violation caused no catching of the
exception)
seh0019.c (-> No exception caught; Which makes sense because there are no
catch handler, but MSVC does catch them)
seh0055.c (-> Test failed; The result is not correct)
sehframes.cpp (-> A certain exception was not caught)

The following tests didn’t even compiled, instead they crashed the compiler:
seh0034.c
seh0035.c
seh0036.c
seh0041.c
seh0042.c
seh0043.c
seh0048.c
seh0049.c
seh0050.c
xcpt4u.c

I hope that helped in some way – any comments or suggestions? I’m up for it!

From: llvm-dev <llvm-dev-bounces at lists.llvm.org> On Behalf Of Aaron
Smith via llvm-dev
Sent: 11 November 2019 23:03
To: llvm-dev at lists.llvm.org
Subject: [llvm-dev] Exceptions on Windows & MSVC

At Microsoft we open sourced some of our compiler tests for exception handling
on github.
https://github.com/microsoft/compiler-tests

We are looking into what it would take to get these to work with clang-cl. I’m
planning to share a design document on the mailing list soon.

Aaron


Als GmbH eingetragen im Handelsregister Bad Homburg v.d.H. HRB 9816, USt.ID-Nr.
DE 114 165 789 Geschäftsführer: Dr. Hiroshi Nakamura, Dr. Robert Plank, Markus
Bode, Heiko Lampert, Takashi Nagano, Takeshi Fukushima. Junichi Tajika
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20191119/81ee4963/attachment.html>

Here is a wiki page and git repo with an implementation of SEH that passes
all the tests for x86.
We're looking for feedback before putting a patch on Phabricator.

https://github.com/tentzen/llvm-project
https://github.com/tentzen/llvm-project/wiki

On Mon, Nov 18, 2019 at 10:59 PM Gaier, Bjoern <Bjoern.Gaier at
horiba.com>
wrote:
> Thank you for this Aaron!
>
>
>
> In our company we rely heavily on the compatibility between Clang-Cl and
> the Visual Studio compiler, lately we encountered big problems with the
> handling of SEH exceptions in our code, so running those tests helped us.
> (Sadly we can’t move to the Visual Studio compiler)
>
>
>
> However, maybe it helps someone if I share the results from running those
> tests… I imported all of the tests into separated projects, compiling them
> with the same settings, with MSVC (v141) and Clang (9), then I compared the
> output. The compiler settings for all those projects were:
>
> /permissive- /GS /GL /W3 /Gy /Zc:wchar_t /Gm- /Ox /Ob2 /sdl /Zc:inline
> /fp:precise /D "_MBCS" /errorReport:prompt /GF- /WX- /Zc:forScope
/Gd /Oy
> /Oi /MD /FC /EHsc /nologo /Ot /diagnostics:classic
>
>
>
> The MSVC compiler only failed the following test:
>
> EH:
> ihateeh.cxx
>
>
>
> Clang however failed multiple tests:
> EH:
>
> ihateeh.cxx
>
>
>
> SEH:
>
> seh0007.c (-> Test failed; The access violation was optimized away,
> leading to a random result; – forcing the access violation caused no
> catching of the exception)
> seh0019.c (-> No exception caught; Which makes sense because there are
no
> catch handler, but MSVC does catch them)
> seh0055.c (-> Test failed; The result is not correct)
>
> sehframes.cpp (-> A certain exception was not caught)
>
>
>
> The following tests didn’t even compiled, instead they crashed the
> compiler:
>
> seh0034.c
>
> seh0035.c
>
> seh0036.c
>
> seh0041.c
>
> seh0042.c
>
> seh0043.c
>
> seh0048.c
>
> seh0049.c
>
> seh0050.c
> xcpt4u.c
>
>
>
> I hope that helped in some way – any comments or suggestions? I’m up for
> it!
>
>
>
> *From:* llvm-dev <llvm-dev-bounces at lists.llvm.org> *On Behalf Of
*Aaron
> Smith via llvm-dev
> *Sent:* 11 November 2019 23:03
> *To:* llvm-dev at lists.llvm.org
> *Subject:* [llvm-dev] Exceptions on Windows & MSVC
>
>
>
> At Microsoft we open sourced some of our compiler tests for exception
> handling on github.
>
> https://github.com/microsoft/compiler-tests
>
>
>
> We are looking into what it would take to get these to work with clang-cl.
> I’m planning to share a design document on the mailing list soon.
>
>
>
> Aaron
>
>
>
>
> Als GmbH eingetragen im Handelsregister Bad Homburg v.d.H. HRB 9816,
> USt.ID-Nr. DE 114 165 789 Geschäftsführer: Dr. Hiroshi Nakamura, Dr. Robert
> Plank, Markus Bode, Heiko Lampert, Takashi Nagano, Takeshi Fukushima.
> Junichi Tajika
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20200327/f6e4402a/attachment.html>