delta/cpython-git.git/Lib/opcode.py, branch v3.2b2

#4617: Previously it was illegal to delete a name from the local

2010-09-10T21:39:53+00:00

namespace if it occurs as a free variable in a nested block.  This limitation
of the compiler has been lifted, and a new opcode introduced (DELETE_DEREF).

This sample was valid in 2.6, but fails to compile in 3.x without this change::

   >>> def f():
   ...     def print_error():
   ...        print(e)
   ...     try:
   ...        something
   ...     except Exception as e:
   ...        print_error()
   ...        # implicit "del e" here


This sample has always been invalid in Python, and now works::

   >>> def outer(x):
   ...     def inner():
   ...        return x
   ...     inner()
   ...     del x

There is no need to bump the PYC magic number: the new opcode is used
for code that did not compile before.

Issue #9225: Remove the ROT_FOUR and DUP_TOPX opcode, the latter replaced

2010-09-04T18:43:52+00:00

by the new (and simpler) DUP_TOP_TWO.  Performance isn't changed, but
our bytecode is a bit simplified.  Patch by Demur Rumed.

Merged revisions 72912,72920,72940 via svnmerge from

2009-06-28T03:18:59+00:00

svn+ssh://pythondev@svn.python.org/python/trunk

........
  r72912 | benjamin.peterson | 2009-05-25 08:13:44 -0500 (Mon, 25 May 2009) | 5 lines

  add a SETUP_WITH opcode

  It speeds up the with statement and correctly looks up the special
  methods involved.
........
  r72920 | benjamin.peterson | 2009-05-25 15:12:57 -0500 (Mon, 25 May 2009) | 1 line

  take into account the fact that SETUP_WITH pushes a finally block
........
  r72940 | benjamin.peterson | 2009-05-26 07:49:59 -0500 (Tue, 26 May 2009) | 1 line

  teach the peepholer about SETUP_WITH
........

http://bugs.python.org/issue4715

2009-02-25T02:25:04+00:00

This patch by Antoine Pitrou optimizes the bytecode for conditional branches by
merging the following "POP_TOP" instruction into the conditional jump.  For
example, the list comprehension "[x for x in l if not x]" produced the
following bytecode:

  1           0 BUILD_LIST               0
              3 LOAD_FAST                0 (.0)
        >>    6 FOR_ITER                23 (to 32)
              9 STORE_FAST               1 (x)
             12 LOAD_FAST                1 (x)
             15 JUMP_IF_TRUE            10 (to 28)
             18 POP_TOP
             19 LOAD_FAST                1 (x)
             22 LIST_APPEND              2
             25 JUMP_ABSOLUTE            6
        >>   28 POP_TOP
             29 JUMP_ABSOLUTE            6
        >>   32 RETURN_VALUE

but after the patch it produces the following bytecode:

  1           0 BUILD_LIST               0
              3 LOAD_FAST                0 (.0)
        >>    6 FOR_ITER                18 (to 27)
              9 STORE_FAST               1 (x)
             12 LOAD_FAST                1 (x)
             15 POP_JUMP_IF_TRUE         6
             18 LOAD_FAST                1 (x)
             21 LIST_APPEND              2
             24 JUMP_ABSOLUTE            6
        >>   27 RETURN_VALUE

Notice that not only the code is shorter, but the conditional jump
(POP_JUMP_IF_TRUE) jumps right to the start of the loop instead of going through
the JUMP_ABSOLUTE at the end. "continue" statements are helped
similarly.

Furthermore, the old jump opcodes (JUMP_IF_FALSE, JUMP_IF_TRUE) have been
replaced by two new opcodes:
- JUMP_IF_TRUE_OR_POP, which jumps if true and pops otherwise
- JUMP_IF_FALSE_OR_POP, which jumps if false and pops otherwise

Merged revisions 67818 via svnmerge from

2008-12-18T11:06:25+00:00

svn+ssh://pythondev@svn.python.org/python/trunk

........
  r67818 | antoine.pitrou | 2008-12-17 01:38:28 +0100 (mer., 17 déc. 2008) | 3 lines

  Issue #2183: Simplify and optimize bytecode for list comprehensions.
........

Remove MAKE_BYTES which is a leftover from the mutable byte literal time.

2008-07-20T21:38:50+00:00

#3021: Antoine Pitrou's Lexical exception handlers

2008-06-11T15:59:43+00:00

Add missing UNPACK_EX opcode.

2008-03-18T20:13:50+00:00

Merged revisions 59541-59561 via svnmerge from

2007-12-19T02:07:34+00:00

svn+ssh://pythondev@svn.python.org/python/trunk

........
  r59544 | raymond.hettinger | 2007-12-18 01:13:45 +0100 (Tue, 18 Dec 2007) | 1 line

  Add more namedtuple() test cases.  Neaten the code and comments.
........
  r59545 | christian.heimes | 2007-12-18 04:38:03 +0100 (Tue, 18 Dec 2007) | 3 lines

  Fixed for #1601: IDLE not working correctly on Windows (Py30a2/IDLE30a1)

  Amaury's ideas works great. Should we build the Python core with WINVER=0x0500 and _WIN32_WINNT=0x0500, too?
........
  r59546 | christian.heimes | 2007-12-18 10:00:13 +0100 (Tue, 18 Dec 2007) | 1 line

  Make it a bit easier to test Tcl/Tk and idle from a build dir.
........
  r59547 | christian.heimes | 2007-12-18 10:12:10 +0100 (Tue, 18 Dec 2007) | 1 line

  Removed several unused files from the PCbuild9 directory. They are relics from the past.
........
  r59548 | raymond.hettinger | 2007-12-18 19:26:18 +0100 (Tue, 18 Dec 2007) | 29 lines

  Speed-up dictionary constructor by about 10%.

  New opcode, STORE_MAP saves the compiler from awkward stack manipulations
  and specializes for dicts using PyDict_SetItem instead of PyObject_SetItem.

  Old disassembly:
                0 BUILD_MAP                0
                3 DUP_TOP
                4 LOAD_CONST               1 (1)
                7 ROT_TWO
                8 LOAD_CONST               2 ('x')
               11 STORE_SUBSCR
               12 DUP_TOP
               13 LOAD_CONST               3 (2)
               16 ROT_TWO
               17 LOAD_CONST               4 ('y')
               20 STORE_SUBSCR

  New disassembly:
                0 BUILD_MAP                0
                3 LOAD_CONST               1 (1)
                6 LOAD_CONST               2 ('x')
                9 STORE_MAP
               10 LOAD_CONST               3 (2)
               13 LOAD_CONST               4 ('y')
               16 STORE_MAP
........
  r59549 | thomas.heller | 2007-12-18 20:00:34 +0100 (Tue, 18 Dec 2007) | 2 lines

  Issue #1642: Fix segfault in ctypes when trying to delete attributes.
........
  r59551 | guido.van.rossum | 2007-12-18 21:10:42 +0100 (Tue, 18 Dec 2007) | 2 lines

  Issue #1645 by Alberto Bertogli.  Fix a comment.
........
  r59553 | raymond.hettinger | 2007-12-18 22:24:09 +0100 (Tue, 18 Dec 2007) | 12 lines

  Give meaning to the oparg for BUILD_MAP:  estimated size of the dictionary.

  Allows dictionaries to be pre-sized (upto 255 elements) saving time lost
  to re-sizes with their attendant mallocs and re-insertions.

  Has zero effect on small dictionaries (5 elements or fewer), a slight
  benefit for dicts upto 22 elements (because they had to resize once
  anyway), and more benefit for dicts upto 255 elements (saving multiple
  resizes during the build-up and reducing the number of collisions on
  the first insertions).  Beyond 255 elements, there is no addional benefit.
........
  r59554 | christian.heimes | 2007-12-18 22:56:09 +0100 (Tue, 18 Dec 2007) | 1 line

  Fixed #1649: IDLE error: dictionary changed size during iteration
........
  r59557 | raymond.hettinger | 2007-12-18 23:21:27 +0100 (Tue, 18 Dec 2007) | 1 line

  Simplify and speedup _asdict() for named tuples.
........
  r59558 | christian.heimes | 2007-12-19 00:22:54 +0100 (Wed, 19 Dec 2007) | 3 lines

  Applied patch #1635: Float patch for inf and nan on Windows (and other platforms).

  The patch unifies float("inf") and repr(float("inf")) on all platforms.
........
  r59559 | raymond.hettinger | 2007-12-19 00:51:15 +0100 (Wed, 19 Dec 2007) | 1 line

  Users demand iterable input for named tuples. The author capitulates.
........
  r59560 | raymond.hettinger | 2007-12-19 01:21:06 +0100 (Wed, 19 Dec 2007) | 1 line

  Beef-up tests for dict literals
........
  r59561 | raymond.hettinger | 2007-12-19 01:27:21 +0100 (Wed, 19 Dec 2007) | 1 line

  Zap a duplicate line
........

Remove the simple slicing API. All slicing is now done with slice objects.

2007-08-30T22:57:53+00:00