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Treat None as a constant.

This commit is contained in:
Raymond Hettinger 2004-07-16 12:16:48 +00:00
parent 11d9b06283
commit 76d962d700
2 changed files with 22 additions and 4 deletions
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2
Misc/NEWS
View File

@ -26,6 +26,8 @@ Core and builtins
- Added C macros Py_CLEAR and Py_VISIT to ease the implementation of
types that support garbage collection.
- Compiler now treats None as a constant.
Extension modules
-----------------

24
Python/compile.c
View File

@ -363,12 +363,13 @@ markblocks(unsigned char *code, int len)
}
static PyObject *
optimize_code(PyObject *code, PyObject* consts)
optimize_code(PyObject *code, PyObject* consts, PyObject *names)
{
int i, j, codelen;
int tgt, tgttgt, opcode;
unsigned char *codestr;
unsigned int *blocks;
char *name;
/* Make a modifiable copy of the code string */
if (!PyString_Check(code))
@ -418,6 +419,21 @@ optimize_code(PyObject *code, PyObject* consts)
continue;
SETARG(codestr, i, (j^1));
codestr[i+3] = NOP;
/* Replace LOAD_GLOBAL/LOAD_NAME None with LOAD_CONST None */
case LOAD_NAME:
case LOAD_GLOBAL:
j = GETARG(codestr, i);
name = PyString_AsString(PyTuple_GET_ITEM(names, j));
if (name == NULL || strcmp(name, "None") != 0)
continue;
for (j=0 ; j < PyTuple_GET_SIZE(consts) ; j++) {
if (PyTuple_GET_ITEM(consts, j) == Py_None) {
codestr[i] = LOAD_CONST;
SETARG(codestr, i, j);
break;
}
}
break;
/* Skip over LOAD_CONST trueconst JUMP_IF_FALSE xx POP_TOP.
@ -441,7 +457,7 @@ optimize_code(PyObject *code, PyObject* consts)
continue;
if (!ISBASICBLOCK(blocks,i,6))
continue;
if (GETARG(codestr, i) == 2 && \
if (GETARG(codestr, i) == 2 &&
GETARG(codestr, i+3) == 2) {
codestr[i] = ROT_TWO;
codestr[i+1] = JUMP_FORWARD;
@ -450,7 +466,7 @@ optimize_code(PyObject *code, PyObject* consts)
codestr[i+5] = NOP;
continue;
}
if (GETARG(codestr, i) == 3 && \
if (GETARG(codestr, i) == 3 &&
GETARG(codestr, i+3) == 3) {
codestr[i] = ROT_THREE;
codestr[i+1] = ROT_TWO;
@ -542,7 +558,7 @@ PyCode_New(int argcount, int nlocals, int stacksize, int flags,
co->co_nlocals = nlocals;
co->co_stacksize = stacksize;
co->co_flags = flags;
co->co_code = optimize_code(code, consts);
co->co_code = optimize_code(code, consts, names);
Py_INCREF(consts);
co->co_consts = consts;
Py_INCREF(names);