Improve Cython debugging

[mkoeppe]

1. Store cython_debug in site-packages/sage/cython_debug instead of in the Cython build directory.

2. Upgrade cysignals:

Tarball: ​https://pypi.python.org/packages/92/15/9ca4a50304fca8debaccac2e9b630626c13f4c91992ca5a86f52732bb983/cysignals-1.6.9.tar.gz#md5=d8155169fefb8ea9c036c2a8ee1495bd

[mkoeppe]

Can you explain what 'cython_debug' is used for precisely, in the description? (Or point to a reference?)

[jdemeyer]

Replying to mkoeppe:

Can you explain what 'cython_debug' is used for precisely, in the description? (Or point to a reference?)

It is used by ​https://github.com/sagemath/cysignals/blob/master/src/scripts/cysignals-CSI-helper.py#L43

[jdemeyer]

Replying to mkoeppe:

fbissey ​proposes to install cython_debug somewhere in SAGE_LOCAL because it is needed for debugging at runtime.

See ​https://trac.sagemath.org/ticket/21480#comment:127 where I question this proposal.

[jdemeyer]

New commits:

​1bf128e	Install the .pyx files
​996759c	No longer add SAGE_SRC to sys.path
​3e99963	Install cython_debug in site-packages/sage

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​76248ff	Fix https://github.com/cython/cython/pull/2095
​edfebbd	Upgrade cysignals to version 1.6.7

[fbissey]

Let's make some progress here. It needs to go to the bots now.

[vbraun]

Tests fail on OSX

[cysignals-1.6.7] Successfully installed cysignals-1.6.7
[cysignals-1.6.7] Cleaning up...
[cysignals-1.6.7] python -B rundoctests.py src/cysignals/*.pyx
[cysignals-1.6.7] cd example && python setup.py clean build
[cysignals-1.6.7] sigaltstack: Cannot allocate memory
[cysignals-1.6.7] Doctesting 5 files.
[cysignals-1.6.7] make[3]: *** [check-doctest] Error 1
[cysignals-1.6.7] Compiling cysignals_example.pyx because it changed.
[cysignals-1.6.7] [1/1] Cythonizing cysignals_example.pyx
[cysignals-1.6.7] running clean
[cysignals-1.6.7] running build
[cysignals-1.6.7] running build_ext
[cysignals-1.6.7] building 'cysignals_example' extension
[cysignals-1.6.7] creating build
[cysignals-1.6.7] creating build/temp.macosx-10.9-x86_64-2.7
[cysignals-1.6.7] gcc -fno-strict-aliasing -g -O2 -DNDEBUG -g -fwrapv -O3 -Wall -Wno-unused -I/Users/buildslave-sage/slave/sage_git/build/local/lib/python2.7/site-packages/cysignals -I/Users/buildslave-sage/slave/sage_git/build/local/include/python2.7 -c cysignals_example.cpp -o build/temp.macosx-10.9-x86_64-2.7/cysignals_example.o
[cysignals-1.6.7] creating build/lib.macosx-10.9-x86_64-2.7
[cysignals-1.6.7] g++ -bundle -undefined dynamic_lookup -L/Users/buildslave-sage/slave/sage_git/build/local/lib -Wl,-rpath,/Users/buildslave-sage/slave/sage_git/build/local/lib -L/Users/buildslave-sage/slave/sage_git/build/local/lib -Wl,-rpath,/Users/buildslave-sage/slave/sage_git/build/local/lib build/temp.macosx-10.9-x86_64-2.7/cysignals_example.o -L/Users/buildslave-sage/slave/sage_git/build/local/lib -o build/lib.macosx-10.9-x86_64-2.7/cysignals_example.so -lpari
[cysignals-1.6.7] make[3]: Target `check-install' not remade because of errors.
[cysignals-1.6.7] 
[cysignals-1.6.7] real	0m9.707s
[cysignals-1.6.7] user	0m8.247s
[cysignals-1.6.7] sys	0m1.497s
[cysignals-1.6.7] ************************************************************************
[cysignals-1.6.7] Error testing package cysignals-1.6.7
[cysignals-1.6.7] ************************************************************************

[jdemeyer]

Replying to vbraun:

Tests fail on OSX

[cysignals-1.6.7] sigaltstack: Cannot allocate memory

That's really strange...

[jdemeyer]

I see, OS X requires a minimum stack size of 2¹⁵ bytes compared to 2¹¹ on Linux and I'm using a hardcoded value of 2¹⁴.

[jdemeyer]

Fixing the stack size is easy but it's not the only problem. The stack overflow test raises SIGILL for some reason...

[jdemeyer]

Strange... it seems that test_stack_overflow() works in the main process but not in a forked child process. Why should that even matter?

[jdemeyer]

As far as I can tell, this is an OS X bug... sigaltstack doesn't survive after a fork. It's as if sigaltstack was never run.

[jdemeyer]

Ugh... even after working around that, there are still problems with sigaltstack. Once it's on the alt stack, it is stuck running there somehow.

[jdemeyer]

Why is OS X implementing sigaltstack so differently? This even works on Solaris...

[git]

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

​83f0d1c	Install cython_debug in site-packages/sage
​7d9e52f	Upgrade cysignals to version 1.6.8

[jdemeyer]

Fixed cysignals on OS X.

[git]

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

​80aeca1	Install cython_debug in site-packages/sage
​fa789c2	Upgrade cysignals to version 1.6.9

[jdemeyer]

New release of cysignals.

[vbraun]

See #21509