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Speed-up dictionary constructor by about 10%.

Browse source 
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
This commit is contained in:
Raymond Hettinger 2007-12-18 18:26:18 +00:00
parent eb103b3577
commit effde12f5f
5 changed files with 19 additions and 5 deletions
Download patch file Download diff file Expand all files Collapse all files

1
Include/opcode.h
View file

@ -45,6 +45,7 @@ extern "C" {
#define DELETE_SLICE 50
/* Also uses 51-53 */
#define STORE_MAP 54
#define INPLACE_ADD 55
#define INPLACE_SUBTRACT 56
#define INPLACE_MULTIPLY 57

1
Lib/opcode.py
View file

@ -85,6 +85,7 @@ def jabs_op(name, op):
def_op('DELETE_SLICE+2', 52)
def_op('DELETE_SLICE+3', 53)
def_op('STORE_MAP', 54)
def_op('INPLACE_ADD', 55)
def_op('INPLACE_SUBTRACT', 56)
def_op('INPLACE_MULTIPLY', 57)

12
Python/ceval.c
View file

@ -2002,6 +2002,18 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
if (x != NULL) continue;
break;
case STORE_MAP:
w = TOP(); /* key */
u = SECOND(); /* value */
v = THIRD(); /* dict */
STACKADJ(-2);
assert (PyDict_CheckExact(v));
err = PyDict_SetItem(v, w, u); /* v[w] = u */
Py_DECREF(u);
Py_DECREF(w);
if (err == 0) continue;
break;
case LOAD_ATTR:
w = GETITEM(names, oparg);
v = TOP();

6
Python/compile.c
View file

@ -729,6 +729,8 @@ opcode_stack_effect(int opcode, int oparg)
return -1;
case STORE_SUBSCR:
return -3;
case STORE_MAP:
return -2;
case DELETE_SUBSCR:
return -2;
@ -2926,13 +2928,11 @@ compiler_visit_expr(struct compiler *c, expr_ty e)
/* We must arrange things just right for STORE_SUBSCR.
It wants the stack to look like (value) (dict) (key) */
for (i = 0; i < n; i++) {
ADDOP(c, DUP_TOP);
VISIT(c, expr,
(expr_ty)asdl_seq_GET(e->v.Dict.values, i));
ADDOP(c, ROT_TWO);
VISIT(c, expr,
(expr_ty)asdl_seq_GET(e->v.Dict.keys, i));
ADDOP(c, STORE_SUBSCR);
ADDOP(c, STORE_MAP);
}
break;
case ListComp_kind:

4
Python/import.c
View file

@ -66,10 +66,10 @@ extern time_t PyOS_GetLastModificationTime(char *, FILE *);
Python 2.5c1: 62121 (fix wrong lnotab with for loops and
storing constants that should have been removed)
Python 2.5c2: 62131 (fix wrong code: for x, in ... in listcomp/genexp)
Python 2.6a0: 62141 (peephole optimizations)
Python 2.6a0: 62151 (peephole optimizations and STORE_MAP opcode)
.
*/
#define MAGIC (62141 | ((long)'\r'<<16) | ((long)'\n'<<24))
#define MAGIC (62151 | ((long)'\r'<<16) | ((long)'\n'<<24))
/* Magic word as global; note that _PyImport_Init() can change the
value of this global to accommodate for alterations of how the