[Patches] [ python-Patches-593627 ] Static names

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Patches item #593627, was opened at 2002-08-11 12:41
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Category: Core (C code)
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Oren Tirosh (orenti)
Assigned to: Nobody/Anonymous (nobody)
Summary: Static names

Initial Comment:
This patch creates static string objects for all built-in 
names and interns then on initialization. The macro 
PyNAME is be used to access static names.

PyNAME(__spam__) is equivalent to 
PyString_InternFromString("__spam__") but is a 
constant expression. It requires the name to be one of 
the built-in names. A linker error will be generated if it 
isn't.

Most conversions of C strings into temporary string 
objects can be eliminated (PyString_FromString, 
PyString_InternFromString). Most string comparisons at 
runtime can also be eliminated. 

Instead of :
if (strcmp(PyString_AsString(name), "__spam__")) ...

This code can be used:
PyString_INTERN(name)
if (name == PyNAME(__spam__)) ...

Where PyString_INTERN is a fast inline check if the 
string is already interned (and it usually is). To prevent 
unbounded accumulation of interned strings the mortal 
interned string patch should also be applied.

The patch converts most of the builtin module to this 
new mode as an example.


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>Comment By: Martin v. Löwis (loewis)
Date: 2002-08-12 09:43

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What is the rationale for this patch? If it is for
performance, what real speed improvements can you report?

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Comment By: Neal Norwitz (nnorwitz)
Date: 2002-08-11 17:54

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I'd like to see the releasing interned string patch applied.
 I think it's almost ready, isn't it?  It would make
patching easier and seems to be a good idea.

For me, the easiest way to produce patches is to use cvs. 
You can keep multiple cvs trees around easy enough (for
having multiple overlapping/independant patches).  To create
patches with cvs:

  cvs diff -C 5 [file1] [file2] ....

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Comment By: Oren Tirosh (orenti)
Date: 2002-08-11 17:44

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Ok, I'll fix the problems with the patch.  What's the best way 
to produce a patch that adds new files? 

Static string objects cannot be released, of course. This 
patch will eventually depend on on the mortal interned strings 
patch to fix it but in the meantime I just disabled releasing 
interned strings because I want to keep the two patches 
independent.

The next version will add a new PyArg_ParseTuple format for 
an interned string to make it easier to use.


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Comment By: Neal Norwitz (nnorwitz)
Date: 2002-08-11 16:46

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Couple of initial comments:
 * this is a reverse patch
 * it seems like there are other changes in here
    - int ob_shash -> long
    - releasing interned strings?
 * dictobject.c is removed?
 * including python headers should use "" not <>

Oren, could you generate a new patch with only the changes
to support PyNAME?  Thanks!

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