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ceval.c: restore str+=str optimization

This commit is contained in:
Victor Stinner 2011-10-02 20:34:20 +02:00
parent a3be613a56
commit d2a915dbf6
1 changed files with 73 additions and 3 deletions
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74
Python/ceval.c
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@ -136,6 +136,8 @@ static PyObject * import_from(PyObject *, PyObject *);
static int import_all_from(PyObject *, PyObject *);
static void format_exc_check_arg(PyObject *, const char *, PyObject *);
static void format_exc_unbound(PyCodeObject *co, int oparg);
static PyObject * unicode_concatenate(PyObject *, PyObject *,
PyFrameObject *, unsigned char *);
static PyObject * special_lookup(PyObject *, char *, PyObject **);
#define NAME_ERROR_MSG \
@ -1507,8 +1509,17 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
TARGET(BINARY_ADD)
w = POP();
v = TOP();
x = PyNumber_Add(v, w);
if (PyUnicode_CheckExact(v) &&
PyUnicode_CheckExact(w)) {
x = unicode_concatenate(v, w, f, next_instr);
/* unicode_concatenate consumed the ref to v */
goto skip_decref_vx;
}
else {
x = PyNumber_Add(v, w);
}
Py_DECREF(v);
skip_decref_vx:
Py_DECREF(w);
SET_TOP(x);
if (x != NULL) DISPATCH();
@ -1659,8 +1670,17 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
TARGET(INPLACE_ADD)
w = POP();
v = TOP();
x = PyNumber_InPlaceAdd(v, w);
if (PyUnicode_CheckExact(v) &&
PyUnicode_CheckExact(w)) {
x = unicode_concatenate(v, w, f, next_instr);
/* unicode_concatenate consumed the ref to v */
goto skip_decref_v;
}
else {
x = PyNumber_InPlaceAdd(v, w);
}
Py_DECREF(v);
skip_decref_v:
Py_DECREF(w);
SET_TOP(x);
if (x != NULL) DISPATCH();
@ -4495,6 +4515,56 @@ format_exc_unbound(PyCodeObject *co, int oparg)
}
}
static PyObject *
unicode_concatenate(PyObject *v, PyObject *w,
PyFrameObject *f, unsigned char *next_instr)
{
PyObject *res;
if (Py_REFCNT(v) == 2) {
/* In the common case, there are 2 references to the value
* stored in 'variable' when the += is performed: one on the
* value stack (in 'v') and one still stored in the
* 'variable'. We try to delete the variable now to reduce
* the refcnt to 1.
*/
switch (*next_instr) {
case STORE_FAST:
{
int oparg = PEEKARG();
PyObject **fastlocals = f->f_localsplus;
if (GETLOCAL(oparg) == v)
SETLOCAL(oparg, NULL);
break;
}
case STORE_DEREF:
{
PyObject **freevars = (f->f_localsplus +
f->f_code->co_nlocals);
PyObject *c = freevars[PEEKARG()];
if (PyCell_GET(c) == v)
PyCell_Set(c, NULL);
break;
}
case STORE_NAME:
{
PyObject *names = f->f_code->co_names;
PyObject *name = GETITEM(names, PEEKARG());
PyObject *locals = f->f_locals;
if (PyDict_CheckExact(locals) &&
PyDict_GetItem(locals, name) == v) {
if (PyDict_DelItem(locals, name) != 0) {
PyErr_Clear();
}
}
break;
}
}
}
res = v;
PyUnicode_Append(&res, w);
return res;
}
#ifdef DYNAMIC_EXECUTION_PROFILE
static PyObject *