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

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This commit is contained in:
Antoine Pitrou 2008-12-17 00:38:28 +00:00
parent 43caaa09ea
commit d0c3515bc5
9 changed files with 34 additions and 63 deletions
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33
Python/compile.c
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@ -693,7 +693,7 @@ opcode_stack_effect(int opcode, int oparg)
return 0;
case LIST_APPEND:
return -2;
return -1;
case BINARY_POWER:
case BINARY_MULTIPLY:
@ -2599,9 +2599,8 @@ compiler_call(struct compiler *c, expr_ty e)
}
static int
compiler_listcomp_generator(struct compiler *c, PyObject *tmpname,
asdl_seq *generators, int gen_index,
expr_ty elt)
compiler_listcomp_generator(struct compiler *c, asdl_seq *generators,
int gen_index, expr_ty elt)
{
/* generate code for the iterator, then each of the ifs,
and then write to the element */
@ -2638,16 +2637,13 @@ compiler_listcomp_generator(struct compiler *c, PyObject *tmpname,
}
if (++gen_index < asdl_seq_LEN(generators))
if (!compiler_listcomp_generator(c, tmpname,
generators, gen_index, elt))
if (!compiler_listcomp_generator(c, generators, gen_index, elt))
return 0;
/* only append after the last for generator */
if (gen_index >= asdl_seq_LEN(generators)) {
if (!compiler_nameop(c, tmpname, Load))
return 0;
VISIT(c, expr, elt);
ADDOP(c, LIST_APPEND);
ADDOP_I(c, LIST_APPEND, gen_index+1);
compiler_use_next_block(c, skip);
}
@ -2659,10 +2655,6 @@ compiler_listcomp_generator(struct compiler *c, PyObject *tmpname,
}
ADDOP_JABS(c, JUMP_ABSOLUTE, start);
compiler_use_next_block(c, anchor);
/* delete the temporary list name added to locals */
if (gen_index == 1)
if (!compiler_nameop(c, tmpname, Del))
return 0;
return 1;
}
@ -2670,21 +2662,10 @@ compiler_listcomp_generator(struct compiler *c, PyObject *tmpname,
static int
compiler_listcomp(struct compiler *c, expr_ty e)
{
identifier tmp;
int rc = 0;
asdl_seq *generators = e->v.ListComp.generators;
assert(e->kind == ListComp_kind);
tmp = compiler_new_tmpname(c);
if (!tmp)
return 0;
ADDOP_I(c, BUILD_LIST, 0);
ADDOP(c, DUP_TOP);
if (compiler_nameop(c, tmp, Store))
rc = compiler_listcomp_generator(c, tmp, generators, 0,
e->v.ListComp.elt);
Py_DECREF(tmp);
return rc;
return compiler_listcomp_generator(c, e->v.ListComp.generators, 0,
e->v.ListComp.elt);
}
static int