Nuitka Release 0.3.6

This is to inform you about the new stable release of Nuitka. It is the extremely compatible Python compiler. Please see the page "What is Nuitka?" for an overview.

The major point this for this release is cleanup work, and generally bug fixes, esp. in the field of importing. This release cleans up many small open ends of Nuitka, closing quite a bunch of consistency TODO items, and then aims at cleaner structures internally, so optimization analysis shall become "easy". It is a correctness and framework release, not a performance improvement at all.

Bug fixes

  • Imports were not respecting the level yet. Code like this was not working, now it is:

    from .. import something
    
  • Absolute and relative imports were e.g. both tried all the time, now if you specify absolute or relative imports, it will be attempted in the same way than CPython does. This can make a difference with compatibility.

  • Functions with a "locals dict" (using locals built-in or exec statement) were not 100% compatible in the way the locals dictionary was updated, this got fixed. It seems that directly updating a dict is not what CPython does at all, instead it only pushes things to the dictionary, when it believes it has to. Nuitka now does the same thing, making it faster and more compatible at the same time with these kind of corner cases.

  • Nested packages didn't work, they do now. Nuitka itself is now successfully using nested packages (e.g. nuitka.transform.optimizations)

New Features

  • The --lto option becomes usable. It's not measurably faster immediately, and it requires g++ 4.6 to be available, but then it at least creates smaller binaries and may provide more optimization in the future.

New Optimization

  • Exceptions raised by pre-computed built-ins, unpacking, etc. are now transformed to raising the exception statically.

Cleanups

  • There is now a getVariableForClosure that a variable provider can use. Before that it guessed from getVariableForReference or getVariableForAssignment what might be the intention. This makes some corner cases easier.
  • Classes, functions and lambdas now also have separate builder and body nodes, which enabled to make getSameScopeNodes() really simple. Either something has children which are all in a new scope or it has them in the same scope.
  • Twisted workarounds like TransitiveProvider are no longer needed, because class builder and class body were separated.
  • New packages nuitka.transform.optimizations and nuitka.transform.finalizations, where the first was nuitka.optimizations before. There is also code in nuitka.transform that was previously in a dedicated module. This allowed to move a lot of displaced code.
  • TreeBuilding now has fast paths for all 3 forms, things that need a "provider", "node", and "source_ref"; things that need "node" and "source_ref"; things that need nothing at all, e.g. pass.
  • Variables now avoid building duplicated instances, but instead share one. Better for analysis of them.

New Tests

  • The Python 2.7 test suite is no longer run with Python 2.6 as it will just crash with the same exception all the time, there is no importlib in 2.6, but every test is using that through test_support.
  • Nested packages are now covered with tests too.
  • Imports of upper level packages are covered now too.

Organizational

  • Updated the "README.txt" with the current plan on optimization.

Numbers

python 2.6:

Pystone(1.1) time for 50000 passes = 0.65
This machine benchmarks at 76923.1 pystones/second

Nuitka 0.3.6 (driven by python 2.6):

Pystone(1.1) time for 50000 passes = 0.31
This machine benchmarks at 161290 pystones/second

This is 109% for 0.3.6, but no change from the previous release. No surprise, because no new effective new optimization means have been implemented. Stay tuned for future release for actual progress.

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