Nuitka Release 0.3.11

Bug fixes

• The order of slice expressions was not correct on x86 as well, and I found that with new tests only. So the porting to ARM revealed a bug category, I previously didn't consider.
• The use of linux2 in the Scons file is potentially incompatible with Linux 3.0, although it seems that at least on Debian the sys.platform was changed back to linux2. Anyway, it's probably best to allow just anything that starts with linux these days.
• The print statement worked like a print function, i.e. it first evaluated all printed expressions, and did the output only then. That is incompatible in case of exceptions, where partial outputs need to be done, and so that got fixed.

New Optimization

• Function calls now each have a dedicated helper function, avoiding in some cases unnecessary work. We will may build further on this and inline PyObject_Call differently for the special cases.

Cleanups

• Moved many C++ helper declarations and inline implementations to dedicated header files for better organisation.

• Some dependencies were removed and consolidated to make the dependency graph sane.

• Multiple decorators were in reverse order in the node tree. The code generation reversed it back, so no bug, yet that was a distorted tree.

  Finding this came from the ARM work, because the "reversal" was in fact just the argument evaluation order of C++ under x86/x64, but on ARM that broke. Correcting it highlighted this issue.

• The deletion of slices, was not using Py_ssize for indexes, disallowing some kinds of optimization, so that was harmonized.

• The function call code generation got a general overhaul. It is now more consistent, has more helpers available, and creates more readable code.

• PyLint is again happier than ever.

New Tests

• There is a new basic test OrderChecks that covers the order of expression evaluation. These problems were otherwise very hard to detect, and in some cases not previously covered at all.
• Executing Nuitka with Python3 (it won't produce correct Python3 C/API code) is now part of the release tests, so non-portable code of Nuitka gets caught.

Organizational

• Support for ARM Linux. I will make a separate posting on the challenges of this. Suffice to say now, that C++ leaves way too much things unspecified.
• The Nuitka git repository now uses "git flow". The new git policy will be detailed in another separate posting.
• There is an unstable develop branch in which the development occurs. For this release ca. 40 commits were done to this branch, before merging it. I am also doing more fine grained commits now.
• Unlike previously, there is master branch for the stable release.
• There is a script "make-dependency-graph.sh" (Update: meanwhile it was renamed to "make-dependency-graph.py") to produce a dependency graphs of Nuitka. I detected a couple of strange things through this.
• The Python3 __pycache__ directories get removed too by the cleanup script.

Numbers

We only have "PyStone" now, and on a new machine, so the numbers cannot be compared to previous releases:

python 2.6:

Pystone(1.1) time for 50000 passes = 0.48
This machine benchmarks at 104167 pystones/second

Nuitka 0.3.11 (driven by python 2.6):

Pystone(1.1) time for 50000 passes = 0.19
This machine benchmarks at 263158 pystones/second

So this a speedup factor of 258%, last time on another machine it was 240%. Yet it only proves that the generated and compiled are more efficient than bytecode, but Nuitka doesn't yet do the relevant optimization. Only once it does, the factor will be significantly higher.

Summary

Overall, there is quite some progress. Nuitka is a lot cleaner now, which will help us later only. I wanted to get this out, mostly because of the bug fixes, and of course just in case somebody attempts to use it on ARM.