Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

GH-93621: reorder code in with/async-with exception exit path to reduce the size of the exception table #93622

Merged
merged 6 commits into from
Jun 10, 2022
Merged

GH-93621: reorder code in with/async-with exception exit path to reduce the size of the exception table #93622

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
6 commits
Select commit Hold shift + click to select a range
acf066c
reorder code in with/async-with exception exit path to reduce the siz…
iritkatriel Jun 8, 2022
4966724
📜🤖 Added by blurb_it.
blurb-it[bot] Jun 9, 2022
dc96fbe
add direct dis tests for with and async-with
iritkatriel Jun 9, 2022
946a191
add some checks for the exception table in dis output
iritkatriel Jun 9, 2022
61729a3
Merge remote-tracking branch 'upstream/main' into with-exception
iritkatriel Jun 9, 2022
38b21f1
update tests after merge
iritkatriel Jun 9, 2022
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
167 changes: 159 additions & 8 deletions Lib/test/test_dis.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -389,6 +389,7 @@ def bug42562():
POP_EXCEPT
RERAISE 1
ExceptionTable:
4 rows
""" % (TRACEBACK_CODE.co_firstlineno,
TRACEBACK_CODE.co_firstlineno + 1,
TRACEBACK_CODE.co_firstlineno + 2,
Expand Down Expand Up @@ -421,6 +422,133 @@ def _fstring(a, b, c, d):
RETURN_VALUE
""" % (_fstring.__code__.co_firstlineno, _fstring.__code__.co_firstlineno + 1)

def _with(c):
iritkatriel marked this conversation as resolved.
Show resolved Hide resolved
with c:
x = 1
y = 2

dis_with = """\
%3d RESUME 0
%3d LOAD_FAST 0 (c)
BEFORE_WITH
POP_TOP
%3d LOAD_CONST 1 (1)
STORE_FAST 1 (x)
%3d LOAD_CONST 0 (None)
LOAD_CONST 0 (None)
LOAD_CONST 0 (None)
CALL 2
POP_TOP
%3d LOAD_CONST 2 (2)
STORE_FAST 2 (y)
LOAD_CONST 0 (None)
RETURN_VALUE
%3d >> PUSH_EXC_INFO
WITH_EXCEPT_START
POP_JUMP_FORWARD_IF_TRUE 1 (to 46)
RERAISE 2
>> POP_TOP
POP_EXCEPT
POP_TOP
POP_TOP
%3d LOAD_CONST 2 (2)
STORE_FAST 2 (y)
LOAD_CONST 0 (None)
RETURN_VALUE
>> COPY 3
POP_EXCEPT
RERAISE 1
ExceptionTable:
2 rows
""" % (_with.__code__.co_firstlineno,
_with.__code__.co_firstlineno + 1,
_with.__code__.co_firstlineno + 2,
_with.__code__.co_firstlineno + 1,
_with.__code__.co_firstlineno + 3,
_with.__code__.co_firstlineno + 1,
_with.__code__.co_firstlineno + 3,
)

async def _asyncwith(c):
async with c:
x = 1
y = 2

dis_asyncwith = """\
%3d RETURN_GENERATOR
POP_TOP
RESUME 0
%3d LOAD_FAST 0 (c)
BEFORE_ASYNC_WITH
GET_AWAITABLE 1
LOAD_CONST 0 (None)
>> SEND 3 (to 22)
YIELD_VALUE 3
RESUME 3
JUMP_BACKWARD_NO_INTERRUPT 4 (to 14)
>> POP_TOP
%3d LOAD_CONST 1 (1)
STORE_FAST 1 (x)
%3d LOAD_CONST 0 (None)
LOAD_CONST 0 (None)
LOAD_CONST 0 (None)
CALL 2
GET_AWAITABLE 2
LOAD_CONST 0 (None)
>> SEND 3 (to 56)
YIELD_VALUE 2
RESUME 3
JUMP_BACKWARD_NO_INTERRUPT 4 (to 48)
>> POP_TOP
%3d LOAD_CONST 2 (2)
STORE_FAST 2 (y)
LOAD_CONST 0 (None)
RETURN_VALUE
%3d >> PUSH_EXC_INFO
WITH_EXCEPT_START
GET_AWAITABLE 2
LOAD_CONST 0 (None)
>> SEND 3 (to 82)
YIELD_VALUE 6
RESUME 3
JUMP_BACKWARD_NO_INTERRUPT 4 (to 74)
>> POP_JUMP_FORWARD_IF_TRUE 1 (to 86)
RERAISE 2
>> POP_TOP
POP_EXCEPT
POP_TOP
POP_TOP
%3d LOAD_CONST 2 (2)
STORE_FAST 2 (y)
LOAD_CONST 0 (None)
RETURN_VALUE
>> COPY 3
POP_EXCEPT
RERAISE 1
ExceptionTable:
2 rows
""" % (_asyncwith.__code__.co_firstlineno,
_asyncwith.__code__.co_firstlineno + 1,
_asyncwith.__code__.co_firstlineno + 2,
_asyncwith.__code__.co_firstlineno + 1,
_asyncwith.__code__.co_firstlineno + 3,
_asyncwith.__code__.co_firstlineno + 1,
_asyncwith.__code__.co_firstlineno + 3,
)


def _tryfinally(a, b):
try:
return a
Expand Down Expand Up @@ -455,6 +583,7 @@ def _tryfinallyconst(b):
POP_EXCEPT
RERAISE 1
ExceptionTable:
2 rows
""" % (_tryfinally.__code__.co_firstlineno,
_tryfinally.__code__.co_firstlineno + 1,
_tryfinally.__code__.co_firstlineno + 2,
Expand Down Expand Up @@ -484,6 +613,7 @@ def _tryfinallyconst(b):
POP_EXCEPT
RERAISE 1
ExceptionTable:
1 row
""" % (_tryfinallyconst.__code__.co_firstlineno,
_tryfinallyconst.__code__.co_firstlineno + 1,
_tryfinallyconst.__code__.co_firstlineno + 2,
Expand Down Expand Up @@ -678,6 +808,18 @@ def assert_offsets_increasing(self, text, delta):
self.assertGreaterEqual(offset, expected_offset, line)
expected_offset = offset + delta

def assert_exception_table_increasing(self, lines):
prev_start, prev_end = -1, -1
count = 0
for line in lines:
m = re.match(r' (\d+) to (\d+) -> \d+ \[\d+\]', line)
start, end = [int(g) for g in m.groups()]
self.assertGreaterEqual(end, start)
self.assertGreater(start, prev_end)
prev_start, prev_end = start, end
count += 1
return count

def strip_offsets(self, text):
lines = text.splitlines(True)
start, end = self.find_offset_column(lines)
Expand All @@ -691,6 +833,9 @@ def strip_offsets(self, text):
res.append(line)
else:
res.append(line[:start] + line[end:])
num_rows = self.assert_exception_table_increasing(lines)
if num_rows:
res.append(f"{num_rows} row{'s' if num_rows > 1 else ''}\n")
return "".join(res)

def do_disassembly_compare(self, got, expected, with_offsets=False):
Expand Down Expand Up @@ -883,6 +1028,12 @@ def test_disassemble_coroutine(self):
def test_disassemble_fstring(self):
self.do_disassembly_test(_fstring, dis_fstring)

def test_disassemble_with(self):
self.do_disassembly_test(_with, dis_with)

def test_disassemble_asyncwith(self):
self.do_disassembly_test(_asyncwith, dis_asyncwith)

def test_disassemble_try_finally(self):
self.do_disassembly_test(_tryfinally, dis_tryfinally)
self.do_disassembly_test(_tryfinallyconst, dis_tryfinallyconst)
Expand Down Expand Up @@ -1471,16 +1622,16 @@ def _prepare_test_cases():
Instruction(opname='RETURN_VALUE', opcode=83, arg=None, argval=None, argrepr='', offset=302, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='PUSH_EXC_INFO', opcode=35, arg=None, argval=None, argrepr='', offset=304, starts_line=25, is_jump_target=False, positions=None),
Instruction(opname='WITH_EXCEPT_START', opcode=49, arg=None, argval=None, argrepr='', offset=306, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='POP_JUMP_FORWARD_IF_TRUE', opcode=115, arg=4, argval=318, argrepr='to 318', offset=308, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='POP_JUMP_FORWARD_IF_TRUE', opcode=115, arg=1, argval=312, argrepr='to 312', offset=308, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='RERAISE', opcode=119, arg=2, argval=2, argrepr='', offset=310, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='COPY', opcode=120, arg=3, argval=3, argrepr='', offset=312, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='POP_TOP', opcode=1, arg=None, argval=None, argrepr='', offset=312, starts_line=None, is_jump_target=True, positions=None),
Instruction(opname='POP_EXCEPT', opcode=89, arg=None, argval=None, argrepr='', offset=314, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='RERAISE', opcode=119, arg=1, argval=1, argrepr='', offset=316, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='POP_TOP', opcode=1, arg=None, argval=None, argrepr='', offset=318, starts_line=None, is_jump_target=True, positions=None),
Instruction(opname='POP_EXCEPT', opcode=89, arg=None, argval=None, argrepr='', offset=320, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='POP_TOP', opcode=1, arg=None, argval=None, argrepr='', offset=322, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='POP_TOP', opcode=1, arg=None, argval=None, argrepr='', offset=324, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='JUMP_BACKWARD', opcode=140, arg=27, argval=274, argrepr='to 274', offset=326, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='POP_TOP', opcode=1, arg=None, argval=None, argrepr='', offset=316, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='POP_TOP', opcode=1, arg=None, argval=None, argrepr='', offset=318, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='JUMP_BACKWARD', opcode=140, arg=24, argval=274, argrepr='to 274', offset=320, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='COPY', opcode=120, arg=3, argval=3, argrepr='', offset=322, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='POP_EXCEPT', opcode=89, arg=None, argval=None, argrepr='', offset=324, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='RERAISE', opcode=119, arg=1, argval=1, argrepr='', offset=326, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='PUSH_EXC_INFO', opcode=35, arg=None, argval=None, argrepr='', offset=328, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='LOAD_GLOBAL', opcode=116, arg=4, argval='ZeroDivisionError', argrepr='ZeroDivisionError', offset=330, starts_line=22, is_jump_target=False, positions=None),
Instruction(opname='CHECK_EXC_MATCH', opcode=36, arg=None, argval=None, argrepr='', offset=342, starts_line=None, is_jump_target=False, positions=None),
Expand Down
1 change: 1 addition & 0 deletions Misc/NEWS.d/next/Core and Builtins/2022-06-09-09-08-29.gh-issue-93621.-_Pn1d.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1 @@
Change order of bytecode instructions emitted for :keyword:`with` and :keyword:`async with` to reduce the number of entries in the exception table.
20 changes: 13 additions & 7 deletions Python/compile.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -5551,20 +5551,26 @@ compiler_visit_keyword(struct compiler *c, keyword_ty k)
static int
compiler_with_except_finish(struct compiler *c, basicblock * cleanup) {
UNSET_LOC(c);
basicblock *exit;
exit = compiler_new_block(c);
if (exit == NULL)
basicblock *suppress = compiler_new_block(c);
if (suppress == NULL) {
return 0;
ADDOP_JUMP(c, POP_JUMP_IF_TRUE, exit);
}
ADDOP_JUMP(c, POP_JUMP_IF_TRUE, suppress);
ADDOP_I(c, RERAISE, 2);
compiler_use_next_block(c, cleanup);
POP_EXCEPT_AND_RERAISE(c);
compiler_use_next_block(c, exit);
compiler_use_next_block(c, suppress);
ADDOP(c, POP_TOP); /* exc_value */
ADDOP(c, POP_BLOCK);
ADDOP(c, POP_EXCEPT);
ADDOP(c, POP_TOP);
ADDOP(c, POP_TOP);
basicblock *exit = compiler_new_block(c);
if (exit == NULL) {
return 0;
}
ADDOP_JUMP(c, JUMP, exit);
compiler_use_next_block(c, cleanup);
POP_EXCEPT_AND_RERAISE(c);
compiler_use_next_block(c, exit);
return 1;
}

Expand Down