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Building URCU in a Cygwin 64 environment

DISCUSSION Jonathan Rajotte Julien 3 participants 4 messages May 31, 2016 – Jun 1, 2016 3 messages not in the archive Kbuild

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#1 lore raw

Hi Sebastien,

I'll simply move the conversation here (from IRC) to have an archive of it.

Quoted 5 lines · Sebastien Boisvert

Hi,

I am in the process of writing a blog article on the use of the LTTng-UST userspace event tracer on Windows.

I am building urcu and LTTng-UST in a Cygwin 64 environment. Then, I plan to use LTTng in Visual Studio Community, so I mostly need headers (.h) and shared libraries (.dll).

Nice!

Quoted 4 lines

When I am building urcu (0.9.2), I get this message:

libtool: link: warning: undefined symbols not allowed in x86_64-unknown-cygwin shared libraries

This seems related to a Windows restriction regarding inter-library dependencies [1], the relevant part:

"Some platforms, such as Windows, do not even allow you this flexibility. In order to build a shared library, it must be entirely self-contained or it must have dependencies known at link time (that is, have references only to symbols that are found in the .lo files or the specified ‘-l’ libraries), and you need to specify the -no-undefined flag. By default, libtool builds only static libraries on these kinds of platforms."

Looks like the -no-undefined might be a good start judging from this patch I found for the urcu cygwin port in yacp [2].

Cheers!

[1] https://www.gnu.org/software/libtool/manual/libtool.html#Inter_002dlibrary-dependencies
[2] https://github.com/fd00/yacp/blob/master/userspace-rcu/userspace-rcu-0.8.7-1bl1.src.patch

Quoted 10 lines

The immediate consequence seems to be the absence of .dll files in the urcu build that I am generating. Otherwise, the build contains static library files and headers.

However, I suppose that the .a static library files also have undefined symbols as I am getting linking issues when building LTTng-UST.

Do you have a clue of what may be the issue here ? Otherwise, I will continue my investigation and get around the issue eventually.
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Signature · 7 lines
Jonathan R. Julien
Efficios

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#3 lore raw

Hi Jonathan,

Thank you for looking into this. I appreciate.

It sounds like I have a solution in hand to continue. That's great.

I just read the text in the web page referenced by the link [1] that you kindly provided to me. This is interesting. Now I know a little bit more about this.

So, Linux can have 'chains of dependencies of potentially infinite length' whereas Windows is limited to shared library DLL files that can not depend on other DLL files; knowing the dependencies is the job of a .exe file and these dependencies must be known at link time.

TIL

+1

Quoted 20 lines · Jonathan Rajotte Julien

Hi Sebastien,

I'll simply move the conversation here (from IRC) to have an archive of it.

Quoted 5 lines · Sebastien Boisvert

Hi,

I am in the process of writing a blog article on the use of the LTTng-UST userspace event tracer on Windows.

I am building urcu and LTTng-UST in a Cygwin 64 environment. Then, I plan to use LTTng in Visual Studio Community, so I mostly need headers (.h) and shared libraries (.dll).

Nice!

Quoted 4 lines

When I am building urcu (0.9.2), I get this message:

libtool: link: warning: undefined symbols not allowed in x86_64-unknown-cygwin shared libraries

This seems related to a Windows restriction regarding inter-library dependencies [1], the relevant part:

Quoted 19 lines

"Some platforms, such as Windows, do not even allow you this flexibility. In order to build a shared library, it must be entirely self-contained or it must have dependencies known at link time (that is, have references only to symbols that are found in the .lo files or the specified ‘-l’ libraries), and you need to specify the -no-undefined flag. By default, libtool builds only static libraries on these kinds of platforms."

Looks like the -no-undefined might be a good start judging from this patch I found for the urcu cygwin port in yacp [2].

Cheers!

[1] https://www.gnu.org/software/libtool/manual/libtool.html#Inter_002dlibrary-dependencies
[2] https://github.com/fd00/yacp/blob/master/userspace-rcu/userspace-rcu-0.8.7-1bl1.src.patch

Quoted 10 lines

The immediate consequence seems to be the absence of .dll files in the urcu build that I am generating. Otherwise, the build contains static library files and headers.

However, I suppose that the .a static library files also have undefined symbols as I am getting linking issues when building LTTng-UST.

Do you have a clue of what may be the issue here ? Otherwise, I will continue my investigation and get around the issue eventually.
_______________________________________________
lttng-dev mailing list
[email protected]
https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev

_______________________________________________
lttng-dev mailing list
[email protected]
https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev

#4 lore raw
In reply to a message not in the archive
Quoted 36 lines · ----- On May 31, 2016, at 4:47 PM, Jonathan Rajotte Julien…

Hi Sebastien,

I'll simply move the conversation here (from IRC) to have an archive of it.

Quoted 8 lines · Sebastien Boisvert

Hi,

I am in the process of writing a blog article on the use of the LTTng-UST userspace event tracer on Windows.

I am building urcu and LTTng-UST in a Cygwin 64 environment. Then, I plan to use LTTng in Visual Studio Community, so I mostly need headers (.h) and shared libraries (.dll).

Nice!

Quoted 5 lines

When I am building urcu (0.9.2), I get this message:

libtool: link: warning: undefined symbols not allowed in x86_64-unknown-cygwin shared libraries

This seems related to a Windows restriction regarding inter-library dependencies [1], the relevant part:

"Some platforms, such as Windows, do not even allow you this flexibility. In order to build a shared library, it must be entirely self-contained or it must have dependencies known at link time (that is, have references only to symbols that are found in the .lo files or the specified ‘-l’ libraries), and you need to specify the -no-undefined flag. By default, libtool builds only static libraries on these kinds of platforms."

Looks like the -no-undefined might be a good start judging from this patch I found for the urcu cygwin port in yacp [2].

Quoted 6 lines

Cheers!

[1]
https://www.gnu.org/software/libtool/manual/libtool.html#Inter_002dlibrary-dependencies
[2]
https://github.com/fd00/yacp/blob/master/userspace-rcu/userspace-rcu-0.8.7-1bl1.src.patch

Is there a way we could adapt this patch to urcu upstream without changing the behavior on non-cygwin builds ?

Thanks,

Mathieu

Quoted 23 lines
Quoted 8 lines

The immediate consequence seems to be the absence of .dll files in the urcu build that I am generating. Otherwise, the build contains static library files and headers.

However, I suppose that the .a static library files also have undefined symbols as I am getting linking issues when building LTTng-UST.

Quoted 6 lines

Do you have a clue of what may be the issue here ? Otherwise, I will continue my investigation and get around the issue eventually.
_______________________________________________
lttng-dev mailing list
[email protected]
https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev

--
Jonathan R. Julien
Efficios

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[email protected]
https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev

Signature · 7 lines
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
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#6 lore raw

Hey Mathieu,

At home (in Cygwin 64), I have a patch for urcu 0.9.2 to fix compilation issues. This patch is however unrelated to building shared libraries (.dll files) in Cygwin.

Here is a patch (inline and attached) to build shared libraries on Cygwin (the one that you requested). This patch is based on userspace-rcu 613086f69b4c8e6cc1b73b4e93d6d0497825d1ee.

I tested it on Ubuntu 14.04 ("behavior on non-cygwin builds"), but not on Cygwin as I don't have a Cygwin system at work.

Commands used to test the patch:

git clone https://github.com/urcu/userspace-rcu.git
cd userspace-rcu/
patch -p1 < ~/patches/0001-Port-build-shared-libraries-in-Cygwin.patch
./bootstrap
./configure --prefix=$HOME/builds/userspace-rcu/613086f69b4c8e6cc1b73b4e93d6d0497825d1ee/date -Iseconds make -j 4
cd tests/
make check
cd ..
make install

Output of the test:

./run.sh unit_tests
./test_uatomic ................... ok
./test_urcu_multiflavor .......... ok
./test_urcu_multiflavor_dynlink .. ok
All tests successful.
Files=3, Tests=78, 0 wallclock secs ( 0.03 usr 0.00 sys + 0.03 cusr 0.01 csys = 0.07 CPU)
Result: PASS

So, the Result is PASS, which is good.

Tonight, I will combine my 2 patches (the one that enables shared libraries in Cygwin, and the one that fixes various compilation issues in Cygwin) and send it to the mailing list for review (along with the output of unit tests in Cygwin).

Z1$ cat ~/patches/0001-Port-build-shared-libraries-in-Cygwin.patch From 1b4f39afc781c1a431b9f52adf25aa0856c86142 Mon Sep 17 00:00:00 2001
From: Sebastien Boisvert <[email protected]>
Date: Wed, 1 Jun 2016 09:53:36 -0400
Subject: [PATCH] Port: build shared libraries in Cygwin

---
 Makefile.am  | 3 +++
 configure.ac | 5 +++++
 2 files changed, 8 insertions(+)
Makefile.am +3 -0
index 672beec..8e25fd9 100644
@@ -8,6 +8,9 @@ AM_LDFLAGS=-version-info $(URCU_LIBRARY_VERSION)
 if !LIBC_INCLUDES_PTHREAD
 AM_LDFLAGS+=-lpthread
 endif
+if USE_CYGWIN
+AM_LDFLAGS+=-no-undefined
+endif
 AM_CFLAGS=-Wall
 
 SUBDIRS = . doc tests
configure.ac +5 -0
index fe1c55d..b3096c6 100644
@@ -134,6 +134,11 @@ AS_CASE([$host],[*-*-linux-androideabi],
 	[AM_CONDITIONAL(TARGET_IS_ANDROID, false)]
 )
 
+AS_CASE([$host],[*-cygwin*],
+	[AM_CONDITIONAL(USE_CYGWIN, true)],
+	[AM_CONDITIONAL(USE_CYGWIN, false)]
+)
+
 AC_SUBST(ARCHTYPE)
 AC_SUBST(SUBARCHTYPE)
 
Signature · 1 line
1.9.1
Quoted 45 lines · Mathieu Desnoyers
Quoted 36 lines · ----- On May 31, 2016, at 4:47 PM, Jonathan Rajotte Julien…

Hi Sebastien,

I'll simply move the conversation here (from IRC) to have an archive of it.

Quoted 8 lines · Sebastien Boisvert

Hi,

I am in the process of writing a blog article on the use of the LTTng-UST userspace event tracer on Windows.

I am building urcu and LTTng-UST in a Cygwin 64 environment. Then, I plan to use LTTng in Visual Studio Community, so I mostly need headers (.h) and shared libraries (.dll).

Nice!

Quoted 5 lines

When I am building urcu (0.9.2), I get this message:

libtool: link: warning: undefined symbols not allowed in x86_64-unknown-cygwin shared libraries

This seems related to a Windows restriction regarding inter-library dependencies [1], the relevant part:

"Some platforms, such as Windows, do not even allow you this flexibility. In order to build a shared library, it must be entirely self-contained or it must have dependencies known at link time (that is, have references only to symbols that are found in the .lo files or the specified ‘-l’ libraries), and you need to specify the -no-undefined flag. By default, libtool builds only static libraries on these kinds of platforms."

Looks like the -no-undefined might be a good start judging from this patch I found for the urcu cygwin port in yacp [2].

Quoted 6 lines

Cheers!

[1]
https://www.gnu.org/software/libtool/manual/libtool.html#Inter_002dlibrary-dependencies
[2]
https://github.com/fd00/yacp/blob/master/userspace-rcu/userspace-rcu-0.8.7-1bl1.src.patch

Quoted 31 lines

Is there a way we could adapt this patch to urcu upstream without changing the behavior on non-cygwin builds ?

Thanks,

Mathieu

Quoted 23 lines
Quoted 8 lines

The immediate consequence seems to be the absence of .dll files in the urcu build that I am generating. Otherwise, the build contains static library files and headers.

However, I suppose that the .a static library files also have undefined symbols as I am getting linking issues when building LTTng-UST.

Quoted 6 lines

Do you have a clue of what may be the issue here ? Otherwise, I will continue my investigation and get around the issue eventually.
_______________________________________________
lttng-dev mailing list
[email protected]
https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev

--
Jonathan R. Julien
Efficios

_______________________________________________
lttng-dev mailing list
[email protected]
https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev

From 1b4f39afc781c1a431b9f52adf25aa0856c86142 Mon Sep 17 00:00:00 2001
From: Sebastien Boisvert <[email protected]>
Date: Wed, 1 Jun 2016 09:53:36 -0400
Subject: [PATCH] Port: build shared libraries in Cygwin

---
 Makefile.am  | 3 +++
 configure.ac | 5 +++++
 2 files changed, 8 insertions(+)
Makefile.am +3 -0
index 672beec..8e25fd9 100644
@@ -8,6 +8,9 @@ AM_LDFLAGS=-version-info $(URCU_LIBRARY_VERSION)
 if !LIBC_INCLUDES_PTHREAD
 AM_LDFLAGS+=-lpthread
 endif
+if USE_CYGWIN
+AM_LDFLAGS+=-no-undefined
+endif
 AM_CFLAGS=-Wall
 
 SUBDIRS = . doc tests
configure.ac +5 -0
index fe1c55d..b3096c6 100644
@@ -134,6 +134,11 @@ AS_CASE([$host],[*-*-linux-androideabi],
 	[AM_CONDITIONAL(TARGET_IS_ANDROID, false)]
 )
 
+AS_CASE([$host],[*-cygwin*],
+	[AM_CONDITIONAL(USE_CYGWIN, true)],
+	[AM_CONDITIONAL(USE_CYGWIN, false)]
+)
+
 AC_SUBST(ARCHTYPE)
 AC_SUBST(SUBARCHTYPE)
 
Signature · 1 line
1.9.1

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