bpo-29469: Optimize literal lists and sets iterating on the AST level. (#4866)

This commit is contained in:
Serhiy Storchaka 2017-12-14 20:24:31 +02:00 committed by GitHub
parent 233ef249cc
commit 15a8728415
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GPG Key ID: 4AEE18F83AFDEB23
4 changed files with 3768 additions and 3782 deletions

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@ -205,7 +205,7 @@ fold_binop(expr_ty node, PyArena *arena)
}
static PyObject*
make_const_tuple(asdl_seq *elts, int make_set)
make_const_tuple(asdl_seq *elts)
{
for (int i = 0; i < asdl_seq_LEN(elts); i++) {
expr_ty e = (expr_ty)asdl_seq_GET(elts, i);
@ -225,11 +225,6 @@ make_const_tuple(asdl_seq *elts, int make_set)
Py_INCREF(v);
PyTuple_SET_ITEM(newval, i, v);
}
/* Need to create frozen_set instead. */
if (make_set) {
Py_SETREF(newval, PyFrozenSet_New(newval));
}
return newval;
}
@ -241,7 +236,7 @@ fold_tuple(expr_ty node, PyArena *arena)
if (node->v.Tuple.ctx != Load)
return 1;
newval = make_const_tuple(node->v.Tuple.elts, 0);
newval = make_const_tuple(node->v.Tuple.elts);
return make_const(node, newval, arena);
}
@ -268,38 +263,48 @@ fold_subscr(expr_ty node, PyArena *arena)
return make_const(node, newval, arena);
}
/* Change literal list or set of constants into constant
tuple or frozenset respectively.
Used for right operand of "in" and "not in" tests and for iterable
in "for" loop and comprehensions.
*/
static int
fold_iter(expr_ty arg, PyArena *arena)
{
PyObject *newval;
if (arg->kind == List_kind) {
newval = make_const_tuple(arg->v.List.elts);
}
else if (arg->kind == Set_kind) {
newval = make_const_tuple(arg->v.Set.elts);
if (newval) {
Py_SETREF(newval, PyFrozenSet_New(newval));
}
}
else {
return 1;
}
return make_const(arg, newval, arena);
}
static int
fold_compare(expr_ty node, PyArena *arena)
{
asdl_int_seq *ops;
asdl_seq *args;
PyObject *newval;
int i;
ops = node->v.Compare.ops;
args = node->v.Compare.comparators;
/* TODO: optimize cases with literal arguments. */
for (i = 0; i < asdl_seq_LEN(ops); i++) {
int op;
expr_ty arg;
asdl_seq *elts;
op = asdl_seq_GET(ops, i);
arg = (expr_ty)asdl_seq_GET(args, i);
/* Change literal list or set in 'in' or 'not in' into
tuple or frozenset respectively. */
/* TODO: do the same when list or set is used as iterable
in for loop and comprehensions? */
if (op != In && op != NotIn)
continue;
if (arg->kind == List_kind)
elts = arg->v.List.elts;
else if (arg->kind == Set_kind)
elts = arg->v.Set.elts;
else continue;
newval = make_const_tuple(elts, arg->kind == Set_kind);
make_const(arg, newval, arena);
/* Change literal list or set in 'in' or 'not in' into
tuple or frozenset respectively. */
i = asdl_seq_LEN(ops) - 1;
int op = asdl_seq_GET(ops, i);
if (op == In || op == NotIn) {
if (!fold_iter((expr_ty)asdl_seq_GET(args, i), arena)) {
return 0;
}
}
return 1;
}
@ -497,6 +502,8 @@ astfold_comprehension(comprehension_ty node_, PyArena* ctx_)
CALL(astfold_expr, expr_ty, node_->target);
CALL(astfold_expr, expr_ty, node_->iter);
CALL_SEQ(astfold_expr, expr_ty, node_->ifs);
CALL(fold_iter, expr_ty, node_->iter);
return 1;
}
@ -565,6 +572,8 @@ astfold_stmt(stmt_ty node_, PyArena* ctx_)
CALL(astfold_expr, expr_ty, node_->v.For.iter);
CALL_SEQ(astfold_stmt, stmt_ty, node_->v.For.body);
CALL_SEQ(astfold_stmt, stmt_ty, node_->v.For.orelse);
CALL(fold_iter, expr_ty, node_->v.For.iter);
break;
case AsyncFor_kind:
CALL(astfold_expr, expr_ty, node_->v.AsyncFor.target);

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@ -173,8 +173,6 @@ copy_op_arg(_Py_CODEUNIT *codestr, Py_ssize_t i, unsigned char op,
new constant (c1, c2, ... cn) can be appended.
Called with codestr pointing to the first LOAD_CONST.
Bails out with no change if one or more of the LOAD_CONSTs is missing.
Also works for BUILD_LIST and BUILT_SET when followed by an "in" or "not in"
test; for BUILD_SET it assembles a frozenset rather than a tuple.
*/
static Py_ssize_t
fold_tuple_on_constants(_Py_CODEUNIT *codestr, Py_ssize_t c_start,
@ -198,15 +196,6 @@ fold_tuple_on_constants(_Py_CODEUNIT *codestr, Py_ssize_t c_start,
PyTuple_SET_ITEM(newconst, i, constant);
}
/* If it's a BUILD_SET, use the PyTuple we just built to create a
PyFrozenSet, and use that as the constant instead: */
if (opcode == BUILD_SET) {
Py_SETREF(newconst, PyFrozenSet_New(newconst));
if (newconst == NULL) {
return -1;
}
}
/* Append folded constant onto consts */
len_consts = PyList_GET_SIZE(consts);
if (PyList_Append(consts, newconst)) {
@ -358,24 +347,15 @@ PyCode_Optimize(PyObject *code, PyObject* consts, PyObject *names,
CONST_STACK_POP(1);
break;
/* Try to fold tuples of constants (includes a case for lists
and sets which are only used for "in" and "not in" tests).
/* Try to fold tuples of constants.
Skip over BUILD_SEQN 1 UNPACK_SEQN 1.
Replace BUILD_SEQN 2 UNPACK_SEQN 2 with ROT2.
Replace BUILD_SEQN 3 UNPACK_SEQN 3 with ROT3 ROT2. */
case BUILD_TUPLE:
case BUILD_LIST:
case BUILD_SET:
j = get_arg(codestr, i);
if (j > 0 && CONST_STACK_LEN() >= j) {
h = lastn_const_start(codestr, op_start, j);
if ((opcode == BUILD_TUPLE &&
ISBASICBLOCK(blocks, h, op_start)) ||
((opcode == BUILD_LIST || opcode == BUILD_SET) &&
((nextop==COMPARE_OP &&
(_Py_OPARG(codestr[nexti]) == PyCmp_IN ||
_Py_OPARG(codestr[nexti]) == PyCmp_NOT_IN)) ||
nextop == GET_ITER) && ISBASICBLOCK(blocks, h, i + 1))) {
if (ISBASICBLOCK(blocks, h, op_start)) {
h = fold_tuple_on_constants(codestr, h, i + 1, opcode,
consts, CONST_STACK_LASTN(j), j);
if (h >= 0) {
@ -387,8 +367,7 @@ PyCode_Optimize(PyObject *code, PyObject* consts, PyObject *names,
}
if (nextop != UNPACK_SEQUENCE ||
!ISBASICBLOCK(blocks, op_start, i + 1) ||
j != get_arg(codestr, nexti) ||
opcode == BUILD_SET)
j != get_arg(codestr, nexti))
break;
if (j < 2) {
fill_nops(codestr, op_start, nexti + 1);