a faster Modulefinder

[theller]

BPO	1353872
Nosy	@theller
Files	modulefinder.patch: Speedup patch

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2006-10-17.19:56:30.000>
created_at = <Date 2005-11-11.11:51:32.000>
labels = ['interpreter-core']
title = 'a faster Modulefinder'
updated_at = <Date 2006-10-17.19:56:30.000>
user = 'https://github.com/theller'

bugs.python.org fields:

activity = <Date 2006-10-17.19:56:30.000>
actor = 'theller'
assignee = 'none'
closed = True
closed_date = None
closer = None
components = ['Interpreter Core']
creation = <Date 2005-11-11.11:51:32.000>
creator = 'theller'
dependencies = []
files = ['6863']
hgrepos = []
issue_num = 1353872
keywords = ['patch']
message_count = 3.0
messages = ['49008', '49009', '49010']
nosy_count = 1.0
nosy_names = ['theller']
pr_nums = []
priority = 'normal'
resolution = 'out of date'
stage = None
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue1353872'
versions = ['Python 2.5']

[theller]

py2exe uses Python's modulefinder to find the modules
and packages that belong to one or more scripts.

For not too small projects, the runtime of modulefinder
is quite long. On my system, the time to find all 533
modules my project needs is around 48 seconds.

So, I profiled the Python 2.4 modulefinder, and patched
it for a speedup of a factor of ~2.5 - the time
required to find the modules drops to around 19 seconds.

[theller]

Logged In: YES
user_id=11105

Here is a description of the changes in the patch:

Modulefinder's scan_code method did call ord() on each
character of the co.co_code string, that took the most time,
and it built the argument (again with ord() calls) of each
bytecode that had one, even if it was never used.

The patch changes the code to

• work on the characters of the co.co_code string, avoiding
  the calls to ord() altogether
• create the bytecodes argument only when needed,
• create the bytecode with struct.pack which is faster.

I did not stop there, so other changes were that the objects
that scan_code needs most are passed as default arguments to
the functions instead of looking them up in the global
namespace.

This patch will probably be in the next py2exe release, so
it will undergo some testing.

I would appreciate comments on the patch.

[theller]

Logged In: YES
user_id=11105

This patch is out of date.