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bpo-22352: Adjust widths in the output of dis.dis() for large line numbers and (#1153) 

instruction offsets.

Add tests for widths of opcode names.
This commit is contained in:
Serhiy Storchaka 2017-04-19 20:36:31 +03:00 committed by GitHub
parent bf623ae884
commit d90045f319
3 changed files with 77 additions and 8 deletions
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30
Lib/dis.py
View File

@ -175,6 +175,9 @@ _Instruction.offset.__doc__ = "Start index of operation within bytecode sequence
_Instruction.starts_line.__doc__ = "Line started by this opcode (if any), otherwise None"
_Instruction.is_jump_target.__doc__ = "True if other code jumps to here, otherwise False"
_OPNAME_WIDTH = 20
_OPARG_WIDTH = 5
class Instruction(_Instruction):
"""Details for a bytecode operation
@ -189,11 +192,12 @@ class Instruction(_Instruction):
is_jump_target - True if other code jumps to here, otherwise False
"""
def _disassemble(self, lineno_width=3, mark_as_current=False):
def _disassemble(self, lineno_width=3, mark_as_current=False, offset_width=4):
"""Format instruction details for inclusion in disassembly output
*lineno_width* sets the width of the line number field (0 omits it)
*mark_as_current* inserts a '-->' marker arrow as part of the line
*offset_width* sets the width of the instruction offset field
"""
fields = []
# Column: Source code line number
@ -214,12 +218,12 @@ class Instruction(_Instruction):
else:
fields.append(' ')
# Column: Instruction offset from start of code sequence
fields.append(repr(self.offset).rjust(4))
fields.append(repr(self.offset).rjust(offset_width))
# Column: Opcode name
fields.append(self.opname.ljust(20))
fields.append(self.opname.ljust(_OPNAME_WIDTH))
# Column: Opcode argument
if self.arg is not None:
fields.append(repr(self.arg).rjust(5))
fields.append(repr(self.arg).rjust(_OPARG_WIDTH))
# Column: Opcode argument details
if self.argrepr:
fields.append('(' + self.argrepr + ')')
@ -339,8 +343,19 @@ def _disassemble_bytes(code, lasti=-1, varnames=None, names=None,
*, file=None, line_offset=0):
# Omit the line number column entirely if we have no line number info
show_lineno = linestarts is not None
# TODO?: Adjust width upwards if max(linestarts.values()) >= 1000?
lineno_width = 3 if show_lineno else 0
if show_lineno:
maxlineno = max(linestarts.values()) + line_offset
if maxlineno >= 1000:
lineno_width = len(str(maxlineno))
else:
lineno_width = 3
else:
lineno_width = 0
maxoffset = len(code) - 2
if maxoffset >= 10000:
offset_width = len(str(maxoffset))
else:
offset_width = 4
for instr in _get_instructions_bytes(code, varnames, names,
constants, cells, linestarts,
line_offset=line_offset):
@ -350,7 +365,8 @@ def _disassemble_bytes(code, lasti=-1, varnames=None, names=None,
if new_source_line:
print(file=file)
is_current_instr = instr.offset == lasti
print(instr._disassemble(lineno_width, is_current_instr), file=file)
print(instr._disassemble(lineno_width, is_current_instr, offset_width),
file=file)
def _disassemble_str(source, *, file=None):
"""Compile the source string, then disassemble the code object."""

52
Lib/test/test_dis.py
View File

@ -175,6 +175,13 @@ _BIG_LINENO_FORMAT = """\
6 RETURN_VALUE
"""
_BIG_LINENO_FORMAT2 = """\
%4d 0 LOAD_GLOBAL 0 (spam)
2 POP_TOP
4 LOAD_CONST 0 (None)
6 RETURN_VALUE
"""
dis_module_expected_results = """\
Disassembly of f:
4 0 LOAD_CONST 0 (None)
@ -360,6 +367,17 @@ class DisTests(unittest.TestCase):
self.assertEqual(dis.opmap["EXTENDED_ARG"], dis.EXTENDED_ARG)
self.assertEqual(dis.opmap["STORE_NAME"], dis.HAVE_ARGUMENT)
def test_widths(self):
for opcode, opname in enumerate(dis.opname):
if opname in ('BUILD_MAP_UNPACK_WITH_CALL',
'BUILD_TUPLE_UNPACK_WITH_CALL'):
continue
with self.subTest(opname=opname):
width = dis._OPNAME_WIDTH
if opcode < dis.HAVE_ARGUMENT:
width += 1 + dis._OPARG_WIDTH
self.assertLessEqual(len(opname), width)
def test_dis(self):
self.do_disassembly_test(_f, dis_f)
@ -387,13 +405,45 @@ class DisTests(unittest.TestCase):
self.do_disassembly_test(func(i), expected)
# Test some larger ranges too
for i in range(300, 5000, 10):
for i in range(300, 1000, 10):
expected = _BIG_LINENO_FORMAT % (i + 2)
self.do_disassembly_test(func(i), expected)
for i in range(1000, 5000, 10):
expected = _BIG_LINENO_FORMAT2 % (i + 2)
self.do_disassembly_test(func(i), expected)
from test import dis_module
self.do_disassembly_test(dis_module, dis_module_expected_results)
def test_big_offsets(self):
def func(count):
namespace = {}
func = "def foo(x):\n " + ";".join(["x = x + 1"] * count) + "\n return x"
exec(func, namespace)
return namespace['foo']
def expected(count, w):
s = ['''\
%*d LOAD_FAST 0 (x)
%*d LOAD_CONST 1 (1)
%*d BINARY_ADD
%*d STORE_FAST 0 (x)
''' % (w, 8*i, w, 8*i + 2, w, 8*i + 4, w, 8*i + 6)
for i in range(count)]
s += ['''\
3 %*d LOAD_FAST 0 (x)
%*d RETURN_VALUE
''' % (w, 8*count, w, 8*count + 2)]
s[0] = ' 2' + s[0][3:]
return ''.join(s)
for i in range(1, 5):
self.do_disassembly_test(func(i), expected(i, 4))
self.do_disassembly_test(func(1249), expected(1249, 4))
self.do_disassembly_test(func(1250), expected(1250, 5))
def test_disassemble_str(self):
self.do_disassembly_test(expr_str, dis_expr_str)
self.do_disassembly_test(simple_stmt_str, dis_simple_stmt_str)

3
Misc/NEWS
View File

@ -313,6 +313,9 @@ Extension Modules
Library
-------
- bpo-22352: Column widths in the output of dis.dis() are now adjusted for
large line numbers and instruction offsets.
- bpo-30061: Fixed crashes in IOBase methods __next__() and readlines() when
readline() or __next__() respectively return non-sizeable object.
Fixed possible other errors caused by not checking results of PyObject_Size(),