mirrors/cpython
1
0
Fork 0
mirror of https://github.com/python/cpython.git synced 2025-09-01 14:38:00 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 8

bpo-33041: Rework compiling an "async for" loop. (#6142)

Browse source 
* Added new opcode END_ASYNC_FOR.
* Setting global StopAsyncIteration no longer breaks "async for" loops.
* Jumping into an "async for" loop is now disabled.
* Jumping out of an "async for" loop no longer corrupts the stack.
* Simplify the compiler.
This commit is contained in:
Serhiy Storchaka 2018-03-23 14:34:35 +02:00 • committed by GitHub
parent c65bf3fe4a
commit 702f8f3611
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
14 changed files with 276 additions and 226 deletions
Download patch file Download diff file Expand all files Collapse all files

120
Python/compile.c
View file

@ -1111,6 +1111,8 @@ stack_effect(int opcode, int oparg, int jump)
return 1;
case GET_YIELD_FROM_ITER:
return 0;
case END_ASYNC_FOR:
return -7;
case FORMAT_VALUE:
/* If there's a fmt_spec on the stack, we go from 2->1,
else 1->1. */
@ -2434,78 +2436,40 @@ compiler_for(struct compiler *c, stmt_ty s)
static int
compiler_async_for(struct compiler *c, stmt_ty s)
{
_Py_IDENTIFIER(StopAsyncIteration);
basicblock *try, *except, *end, *after_try, *try_cleanup,
*after_loop_else;
PyObject *stop_aiter_error = _PyUnicode_FromId(&PyId_StopAsyncIteration);
if (stop_aiter_error == NULL) {
return 0;
}
try = compiler_new_block(c);
basicblock *start, *except, *end;
start = compiler_new_block(c);
except = compiler_new_block(c);
end = compiler_new_block(c);
after_try = compiler_new_block(c);
try_cleanup = compiler_new_block(c);
after_loop_else = compiler_new_block(c);
if (try == NULL || except == NULL || end == NULL
|| after_try == NULL || try_cleanup == NULL
|| after_loop_else == NULL)
return 0;
if (!compiler_push_fblock(c, FOR_LOOP, try, end))
if (start == NULL || except == NULL || end == NULL)
return 0;
VISIT(c, expr, s->v.AsyncFor.iter);
ADDOP(c, GET_AITER);
compiler_use_next_block(c, try);
compiler_use_next_block(c, start);
if (!compiler_push_fblock(c, FOR_LOOP, start, end))
return 0;
/* SETUP_FINALLY to guard the __anext__ call */
ADDOP_JREL(c, SETUP_FINALLY, except);
if (!compiler_push_fblock(c, EXCEPT, try, NULL))
return 0;
ADDOP(c, GET_ANEXT);
ADDOP_O(c, LOAD_CONST, Py_None, consts);
ADDOP(c, YIELD_FROM);
ADDOP(c, POP_BLOCK); /* for SETUP_FINALLY */
VISIT(c, expr, s->v.AsyncFor.target);
compiler_pop_fblock(c, EXCEPT, try);
ADDOP_JREL(c, JUMP_FORWARD, after_try);
/* Success block for __anext__ */
VISIT(c, expr, s->v.AsyncFor.target);
VISIT_SEQ(c, stmt, s->v.AsyncFor.body);
ADDOP_JABS(c, JUMP_ABSOLUTE, start);
compiler_pop_fblock(c, FOR_LOOP, start);
/* Except block for __anext__ */
compiler_use_next_block(c, except);
ADDOP(c, DUP_TOP);
ADDOP_O(c, LOAD_GLOBAL, stop_aiter_error, names);
ADDOP_I(c, COMPARE_OP, PyCmp_EXC_MATCH);
ADDOP_JABS(c, POP_JUMP_IF_FALSE, try_cleanup);
ADDOP(c, POP_TOP);
ADDOP(c, POP_TOP);
ADDOP(c, POP_TOP);
ADDOP(c, POP_EXCEPT); /* for SETUP_FINALLY */
ADDOP(c, POP_TOP); /* pop iterator from stack */
ADDOP_JABS(c, JUMP_ABSOLUTE, after_loop_else);
compiler_use_next_block(c, try_cleanup);
ADDOP(c, END_FINALLY);
/* Success block for __anext__ */
compiler_use_next_block(c, after_try);
VISIT_SEQ(c, stmt, s->v.AsyncFor.body);
ADDOP_JABS(c, JUMP_ABSOLUTE, try);
compiler_pop_fblock(c, FOR_LOOP, try);
ADDOP(c, END_ASYNC_FOR);
/* `else` block */
compiler_use_next_block(c, after_loop_else);
VISIT_SEQ(c, stmt, s->v.For.orelse);
compiler_use_next_block(c, end);
@ -4003,28 +3967,14 @@ compiler_async_comprehension_generator(struct compiler *c,
asdl_seq *generators, int gen_index,
expr_ty elt, expr_ty val, int type)
{
_Py_IDENTIFIER(StopAsyncIteration);
comprehension_ty gen;
basicblock *anchor, *if_cleanup, *try,
*after_try, *except, *try_cleanup;
basicblock *start, *if_cleanup, *except;
Py_ssize_t i, n;
PyObject *stop_aiter_error = _PyUnicode_FromId(&PyId_StopAsyncIteration);
if (stop_aiter_error == NULL) {
return 0;
}
try = compiler_new_block(c);
after_try = compiler_new_block(c);
try_cleanup = compiler_new_block(c);
start = compiler_new_block(c);
except = compiler_new_block(c);
if_cleanup = compiler_new_block(c);
anchor = compiler_new_block(c);
if (if_cleanup == NULL || anchor == NULL ||
try == NULL || after_try == NULL ||
except == NULL || try_cleanup == NULL) {
if (start == NULL || if_cleanup == NULL || except == NULL) {
return 0;
}
@ -4041,39 +3991,14 @@ compiler_async_comprehension_generator(struct compiler *c,
ADDOP(c, GET_AITER);
}
compiler_use_next_block(c, try);
compiler_use_next_block(c, start);
ADDOP_JREL(c, SETUP_FINALLY, except);
if (!compiler_push_fblock(c, EXCEPT, try, NULL))
return 0;
ADDOP(c, GET_ANEXT);
ADDOP_O(c, LOAD_CONST, Py_None, consts);
ADDOP(c, YIELD_FROM);
ADDOP(c, POP_BLOCK);
VISIT(c, expr, gen->target);
compiler_pop_fblock(c, EXCEPT, try);
ADDOP_JREL(c, JUMP_FORWARD, after_try);
compiler_use_next_block(c, except);
ADDOP(c, DUP_TOP);
ADDOP_O(c, LOAD_GLOBAL, stop_aiter_error, names);
ADDOP_I(c, COMPARE_OP, PyCmp_EXC_MATCH);
ADDOP_JABS(c, POP_JUMP_IF_FALSE, try_cleanup);
ADDOP(c, POP_TOP);
ADDOP(c, POP_TOP);
ADDOP(c, POP_TOP);
ADDOP(c, POP_EXCEPT); /* for SETUP_FINALLY */
ADDOP_JABS(c, JUMP_ABSOLUTE, anchor);
compiler_use_next_block(c, try_cleanup);
ADDOP(c, END_FINALLY);
compiler_use_next_block(c, after_try);
n = asdl_seq_LEN(gen->ifs);
for (i = 0; i < n; i++) {
@ -4118,9 +4043,10 @@ compiler_async_comprehension_generator(struct compiler *c,
}
}
compiler_use_next_block(c, if_cleanup);
ADDOP_JABS(c, JUMP_ABSOLUTE, try);
compiler_use_next_block(c, anchor);
ADDOP(c, POP_TOP);
ADDOP_JABS(c, JUMP_ABSOLUTE, start);
compiler_use_next_block(c, except);
ADDOP(c, END_ASYNC_FOR);
return 1;
}