ai-content-maker/.venv/Lib/site-packages/numba/tests/test_debuginfo.py

759 lines
28 KiB
Python

from collections import namedtuple
import inspect
import re
import numpy as np
import math
from textwrap import dedent
import unittest
import warnings
from numba.tests.support import (TestCase, override_config,
ignore_internal_warnings)
from numba import jit, njit
from numba.core import types
from numba.core.datamodel import default_manager
from numba.core.errors import NumbaDebugInfoWarning
import llvmlite.binding as llvm
#NOTE: These tests are potentially sensitive to changes in SSA or lowering
# behaviour and may need updating should changes be made to the corresponding
# algorithms.
class TestDebugInfo(TestCase):
"""
These tests only checks the compiled assembly for debuginfo.
"""
def _getasm(self, fn, sig):
fn.compile(sig)
return fn.inspect_asm(sig)
def _check(self, fn, sig, expect):
asm = self._getasm(fn, sig=sig)
m = re.search(r"\.section.+debug", asm, re.I)
got = m is not None
self.assertEqual(expect, got, msg='debug info not found in:\n%s' % asm)
def test_no_debuginfo_in_asm(self):
@jit(nopython=True, debug=False)
def foo(x):
return x
self._check(foo, sig=(types.int32,), expect=False)
def test_debuginfo_in_asm(self):
@jit(nopython=True, debug=True)
def foo(x):
return x
self._check(foo, sig=(types.int32,), expect=True)
def test_environment_override(self):
with override_config('DEBUGINFO_DEFAULT', 1):
# Using default value
@jit(nopython=True)
def foo(x):
return x
self._check(foo, sig=(types.int32,), expect=True)
# User override default
@jit(nopython=True, debug=False)
def bar(x):
return x
self._check(bar, sig=(types.int32,), expect=False)
def test_llvm_inliner_flag_conflict(self):
# bar will be marked as 'alwaysinline', but when DEBUGINFO_DEFAULT is
# set functions are marked as 'noinline' this results in a conflict.
# baz will be marked as 'noinline' as a result of DEBUGINFO_DEFAULT
@njit(forceinline=True)
def bar(x):
return math.sin(x)
@njit(forceinline=False)
def baz(x):
return math.cos(x)
@njit
def foo(x):
a = bar(x)
b = baz(x)
return a, b
# check it compiles
with override_config('DEBUGINFO_DEFAULT', 1):
result = foo(np.pi)
self.assertPreciseEqual(result, foo.py_func(np.pi))
# check the LLVM IR has bar marked as 'alwaysinline' and baz as noinline
full_ir = foo.inspect_llvm(foo.signatures[0])
module = llvm.parse_assembly(full_ir)
name = foo.overloads[foo.signatures[0]].fndesc.mangled_name
funcs = [x for x in module.functions if x.name == name]
self.assertEqual(len(funcs), 1)
func = funcs[0]
# find the function calls and save the associated statements
f_names = []
for blk in func.blocks:
for stmt in blk.instructions:
if stmt.opcode == 'call':
# stmt.function.name This is the function being called
f_names.append(str(stmt).strip())
# Need to check there's two specific things in the calls in the IR
# 1. a call to the llvm.sin.f64 intrinsic, this is from the inlined bar
# 2. a call to the baz function, this is from the noinline baz
found_sin = False
found_baz = False
baz_name = baz.overloads[baz.signatures[0]].fndesc.mangled_name
for x in f_names:
if not found_sin and re.match('.*llvm.sin.f64.*', x):
found_sin = True
if not found_baz and re.match(f'.*{baz_name}.*', x):
found_baz = True
self.assertTrue(found_sin)
self.assertTrue(found_baz)
class TestDebugInfoEmission(TestCase):
""" Tests that debug info is emitted correctly.
"""
_NUMBA_OPT_0_ENV = {'NUMBA_OPT': '0'}
def _get_llvmir(self, fn, sig):
with override_config('OPT', 0):
fn.compile(sig)
return fn.inspect_llvm(sig)
def _get_metadata(self, fn, sig):
ll = self._get_llvmir(fn, sig).splitlines()
meta_re = re.compile(r'![0-9]+ =.*')
metadata = []
for line in ll:
if meta_re.match(line):
metadata.append(line)
return metadata
def _get_metadata_map(self, metadata):
"""Gets the map of DI label to md, e.g.
'!33' -> '!{!"branch_weights", i32 1, i32 99}'
"""
metadata_definition_map = dict()
meta_definition_split = re.compile(r'(![0-9]+) = (.*)')
for line in metadata:
matched = meta_definition_split.match(line)
if matched:
dbg_val, info = matched.groups()
metadata_definition_map[dbg_val] = info
return metadata_definition_map
def _get_lines_from_debuginfo(self, metadata):
# Get the lines contained in the debug info
md_def_map = self._get_metadata_map(metadata)
lines = set()
for md in md_def_map.values():
m = re.match(r"!DILocation\(line: (\d+),", md)
if m:
ln = int(m.group(1))
lines.add(ln)
return lines
def test_DW_LANG(self):
@njit(debug=True)
def foo():
pass
metadata = self._get_metadata(foo, sig=())
DICompileUnit = metadata[0]
self.assertEqual('!0', DICompileUnit[:2])
self.assertIn('!DICompileUnit(language: DW_LANG_C_plus_plus',
DICompileUnit)
self.assertIn('producer: "clang (Numba)"', DICompileUnit)
def test_DILocation(self):
""" Tests that DILocation information is reasonable.
"""
@njit(debug=True, error_model='numpy')
def foo(a):
b = a + 1.23
c = b * 2.34
d = b / c
print(d)
return d
# the above produces LLVM like:
# define function() {
# entry:
# alloca
# store 0 to alloca
# <arithmetic for doing the operations on b, c, d>
# setup for print
# branch
# other_labels:
# ... <elided>
# }
#
# The following checks that:
# * the alloca and store have no !dbg
# * the arithmetic occurs in the order defined and with !dbg
# * that the !dbg entries are monotonically increasing in value with
# source line number
sig = (types.float64,)
metadata = self._get_metadata(foo, sig=sig)
full_ir = self._get_llvmir(foo, sig=sig)
module = llvm.parse_assembly(full_ir)
name = foo.overloads[foo.signatures[0]].fndesc.mangled_name
funcs = [x for x in module.functions if x.name == name]
self.assertEqual(len(funcs), 1)
func = funcs[0]
blocks = [x for x in func.blocks]
self.assertGreater(len(blocks), 1)
block = blocks[0]
# Find non-call instr and check the sequence is as expected
instrs = [x for x in block.instructions if x.opcode != 'call']
op_expect = {'fadd', 'fmul', 'fdiv'}
started = False
for x in instrs:
if x.opcode in op_expect:
op_expect.remove(x.opcode)
if not started:
started = True
elif op_expect and started:
self.fail("Math opcodes are not contiguous")
self.assertFalse(op_expect, "Math opcodes were not found")
# Parse out metadata from end of each line, check it monotonically
# ascends with LLVM source line. Also store all the dbg references,
# these will be checked later.
line2dbg = set()
re_dbg_ref = re.compile(r'.*!dbg (![0-9]+).*$')
found = -1
for instr in instrs:
inst_as_str = str(instr)
matched = re_dbg_ref.match(inst_as_str)
if not matched:
# if there's no match, ensure it is one of alloca or store,
# it's important that the zero init/alloca instructions have
# no dbg data
accepted = ('alloca ', 'store ')
self.assertTrue(any([x in inst_as_str for x in accepted]))
continue
groups = matched.groups()
self.assertEqual(len(groups), 1)
dbg_val = groups[0]
int_dbg_val = int(dbg_val[1:])
if found >= 0:
self.assertTrue(int_dbg_val >= found)
found = int_dbg_val
# some lines will alias dbg info, this is fine, it's only used to
# make sure that the line numbers are correct WRT python
line2dbg.add(dbg_val)
pysrc, pysrc_line_start = inspect.getsourcelines(foo)
# build a map of dbg reference to DI* information
metadata_definition_map = self._get_metadata_map(metadata)
# Pull out metadata entries referred to by the llvm line end !dbg
# check they match the python source, the +2 is for the @njit decorator
# and the function definition line.
offsets = [0, # b = a + 1
1, # a * 2.34
2, # d = b / c
3, # print(d)
]
pyln_range = [pysrc_line_start + 2 + x for x in offsets]
# do the check
for (k, line_no) in zip(sorted(line2dbg, key=lambda x: int(x[1:])),
pyln_range):
dilocation_info = metadata_definition_map[k]
self.assertIn(f'line: {line_no}', dilocation_info)
# Check that variable "a" is declared as on the same line as function
# definition.
expr = r'.*!DILocalVariable\(name: "a",.*line: ([0-9]+),.*'
match_local_var_a = re.compile(expr)
for entry in metadata_definition_map.values():
matched = match_local_var_a.match(entry)
if matched:
groups = matched.groups()
self.assertEqual(len(groups), 1)
dbg_line = int(groups[0])
# +1 for the decorator.
# Recall that Numba's DWARF refers to the "def" line, but
# `inspect` uses the decorator as the first line.
defline = pysrc_line_start + 1
self.assertEqual(dbg_line, defline)
break
else:
self.fail('Assertion on DILocalVariable not made')
@TestCase.run_test_in_subprocess(envvars=_NUMBA_OPT_0_ENV)
def test_DILocation_entry_blk(self):
# Needs a subprocess as jitting literally anything at any point in the
# lifetime of the process ends up with a codegen at opt 3. This is not
# amenable to this test!
# This test relies on the CFG not being simplified as it checks the jump
# from the entry block to the first basic block. Force OPT as 0, if set
# via the env var the targetmachine and various pass managers all end up
# at OPT 0 and the IR is minimally transformed prior to lowering to ELF.
#
# This tests that the unconditional jump emitted at the tail of
# the entry block has no debug metadata associated with it. In practice,
# if debug metadata is associated with it, it manifests as the
# prologue_end being associated with the end_sequence or similar (due to
# the way code gen works for the entry block).
@njit(debug=True)
def foo(a):
return a + 1
foo(123)
full_ir = foo.inspect_llvm(foo.signatures[0])
# The above produces LLVM like:
#
# define function() {
# entry:
# alloca
# store 0 to alloca
# unconditional jump to body:
#
# body:
# ... <elided>
# }
module = llvm.parse_assembly(full_ir)
name = foo.overloads[foo.signatures[0]].fndesc.mangled_name
funcs = [x for x in module.functions if x.name == name]
self.assertEqual(len(funcs), 1)
func = funcs[0]
blocks = [x for x in func.blocks]
self.assertEqual(len(blocks), 2)
entry_block, body_block = blocks
# Assert that the tail of the entry block is an unconditional jump to
# the body block and that the jump has no associated debug info.
entry_instr = [x for x in entry_block.instructions]
ujmp = entry_instr[-1]
self.assertEqual(ujmp.opcode, 'br')
ujmp_operands = [x for x in ujmp.operands]
self.assertEqual(len(ujmp_operands), 1)
target_data = ujmp_operands[0]
target = str(target_data).split(':')[0].strip()
# check the unconditional jump target is to the body block
self.assertEqual(target, body_block.name)
# check the uncondition jump instr itself has no metadata
self.assertTrue(str(ujmp).endswith(target))
@TestCase.run_test_in_subprocess(envvars=_NUMBA_OPT_0_ENV)
def test_DILocation_decref(self):
""" This tests that decref's generated from `ir.Del`s as variables go
out of scope do not have debuginfo associated with them (the location of
`ir.Del` is an implementation detail).
"""
@njit(debug=True)
def sink(*x):
pass
# This function has many decrefs!
@njit(debug=True)
def foo(a):
x = (a, a)
if a[0] == 0:
sink(x)
return 12
z = x[0][0]
return z
sig = (types.float64[::1],)
full_ir = self._get_llvmir(foo, sig=sig)
# make sure decref lines end with `meminfo.<number>)` without !dbg info.
count = 0
for line in full_ir.splitlines():
line_stripped = line.strip()
if line_stripped.startswith('call void @NRT_decref'):
self.assertRegex(line, r'.*meminfo\.[0-9]+\)$')
count += 1
self.assertGreater(count, 0) # make sure there were some decrefs!
def test_DILocation_undefined(self):
""" Tests that DILocation information for undefined vars is associated
with the line of the function definition (so it ends up in the prologue)
"""
@njit(debug=True)
def foo(n):
if n:
if n > 0:
c = 0
return c
else:
# variable c is not defined in this branch
c += 1
return c
sig = (types.intp,)
metadata = self._get_metadata(foo, sig=sig)
pysrc, pysrc_line_start = inspect.getsourcelines(foo)
# Looks for versions of variable "c" and captures the line number
expr = r'.*!DILocalVariable\(name: "c\$?[0-9]?",.*line: ([0-9]+),.*'
matcher = re.compile(expr)
associated_lines = set()
for md in metadata:
match = matcher.match(md)
if match:
groups = match.groups()
self.assertEqual(len(groups), 1)
associated_lines.add(int(groups[0]))
# 3 versions of 'c': `c = 0`, `return c`, `c+=1`
self.assertEqual(len(associated_lines), 3)
self.assertIn(pysrc_line_start, associated_lines)
def test_DILocation_versioned_variables(self):
""" Tests that DILocation information for versions of variables matches
up to their definition site."""
# Note: there's still something wrong in the DI/SSA naming, the ret c is
# associated with the logically first definition.
@njit(debug=True)
def foo(n):
if n:
c = 5
else:
c = 1
# prevents inline of return on py310
py310_defeat1 = 1 # noqa
py310_defeat2 = 2 # noqa
py310_defeat3 = 3 # noqa
py310_defeat4 = 4 # noqa
return c
sig = (types.intp,)
metadata = self._get_metadata(foo, sig=sig)
pysrc, pysrc_line_start = inspect.getsourcelines(foo)
# Looks for SSA versioned names i.e. <basename>$<version id> of the
# variable 'c' and captures the line
expr = r'.*!DILocalVariable\(name: "c\$[0-9]?",.*line: ([0-9]+),.*'
matcher = re.compile(expr)
associated_lines = set()
for md in metadata:
match = matcher.match(md)
if match:
groups = match.groups()
self.assertEqual(len(groups), 1)
associated_lines.add(int(groups[0]))
self.assertEqual(len(associated_lines), 2) # 2 SSA versioned names 'c'
# Now find the `c = ` lines in the python source
py_lines = set()
for ix, pyln in enumerate(pysrc):
if 'c = ' in pyln:
py_lines.add(ix + pysrc_line_start)
self.assertEqual(len(py_lines), 2) # 2 assignments to c
# check that the DILocation from the DI for `c` matches the python src
self.assertEqual(associated_lines, py_lines)
def test_numeric_scalars(self):
""" Tests that dwarf info is correctly emitted for numeric scalars."""
DI = namedtuple('DI', 'name bits encoding')
type_infos = {np.float32: DI("float32", 32, "DW_ATE_float"),
np.float64: DI("float64", 64, "DW_ATE_float"),
np.int8: DI("int8", 8, "DW_ATE_signed"),
np.int16: DI("int16", 16, "DW_ATE_signed"),
np.int32: DI("int32", 32, "DW_ATE_signed"),
np.int64: DI("int64", 64, "DW_ATE_signed"),
np.uint8: DI("uint8", 8, "DW_ATE_unsigned"),
np.uint16: DI("uint16", 16, "DW_ATE_unsigned"),
np.uint32: DI("uint32", 32, "DW_ATE_unsigned"),
np.uint64: DI("uint64", 64, "DW_ATE_unsigned"),
np.complex64: DI("complex64", 64,
"DW_TAG_structure_type"),
np.complex128: DI("complex128", 128,
"DW_TAG_structure_type"),}
for ty, dwarf_info in type_infos.items():
@njit(debug=True)
def foo():
a = ty(10)
return a
metadata = self._get_metadata(foo, sig=())
metadata_definition_map = self._get_metadata_map(metadata)
for k, v in metadata_definition_map.items():
if 'DILocalVariable(name: "a"' in v:
lvar = metadata_definition_map[k]
break
else:
assert 0, "missing DILocalVariable 'a'"
type_marker = re.match('.*type: (![0-9]+).*', lvar).groups()[0]
type_decl = metadata_definition_map[type_marker]
if 'DW_ATE' in dwarf_info.encoding:
expected = (f'!DIBasicType(name: "{dwarf_info.name}", '
f'size: {dwarf_info.bits}, '
f'encoding: {dwarf_info.encoding})')
self.assertEqual(type_decl, expected)
else: # numerical complex type
# Don't match the whole string, just the known parts
raw_flt = 'float' if dwarf_info.bits == 64 else 'double'
expected = (f'distinct !DICompositeType('
f'tag: {dwarf_info.encoding}, '
f'name: "{dwarf_info.name} '
f'({{{raw_flt}, {raw_flt}}})", '
f'size: {dwarf_info.bits}')
self.assertIn(expected, type_decl)
def test_arrays(self):
@njit(debug=True)
def foo():
a = np.ones((2, 3), dtype=np.float64)
return a
metadata = self._get_metadata(foo, sig=())
metadata_definition_map = self._get_metadata_map(metadata)
for k, v in metadata_definition_map.items():
if 'DILocalVariable(name: "a"' in v:
lvar = metadata_definition_map[k]
break
else:
assert 0, "missing DILocalVariable 'a'"
type_marker = re.match('.*type: (![0-9]+).*', lvar).groups()[0]
type_decl = metadata_definition_map[type_marker]
# check type
self.assertIn("!DICompositeType(tag: DW_TAG_structure_type", type_decl)
# check name encoding
self.assertIn(f'name: "{str(types.float64[:, ::1])}', type_decl)
# pop out the "elements" of the composite type
match_elements = re.compile(r'.*elements: (![0-9]+),.*')
elem_matches = match_elements.match(type_decl).groups()
self.assertEqual(len(elem_matches), 1)
elem_match = elem_matches[0]
# The match should be something like, it's the elements from an array
# data model.
# !{!35, !36, !37, !39, !40, !43, !45}'
struct_markers = metadata_definition_map[elem_match]
struct_pattern = '!{' + '(![0-9]+), ' * 6 + '(![0-9]+)}'
match_struct = re.compile(struct_pattern)
struct_member_matches = match_struct.match(struct_markers).groups()
self.assertIsNotNone(struct_member_matches is not None)
data_model = default_manager.lookup(types.float64[:, ::1])
self.assertEqual(len(struct_member_matches), len(data_model._fields))
ptr_size = types.intp.bitwidth
ptr_re = (r'!DIDerivedType\(tag: DW_TAG_pointer_type, '
rf'baseType: ![0-9]+, size: {ptr_size}\)')
int_re = (rf'!DIBasicType\(name: "int{ptr_size}", size: {ptr_size}, '
r'encoding: DW_ATE_signed\)')
utuple_re = (r'!DICompositeType\(tag: DW_TAG_array_type, '
rf'name: "UniTuple\(int{ptr_size} x 2\) '
rf'\(\[2 x i{ptr_size}\]\)", baseType: ![0-9]+, '
rf'size: {2 * ptr_size}, elements: ![0-9]+, '
rf'identifier: "\[2 x i{ptr_size}\]"\)')
expected = {'meminfo': ptr_re,
'parent': ptr_re,
'nitems': int_re,
'itemsize': int_re,
'data': ptr_re,
'shape': utuple_re,
'strides': utuple_re}
# look for `baseType: <>` for the type
base_type_pattern = r'!DIDerivedType\(.*, baseType: (![0-9]+),.*'
base_type_matcher = re.compile(base_type_pattern)
for ix, field in enumerate(data_model._fields):
derived_type = metadata_definition_map[struct_member_matches[ix]]
self.assertIn("DIDerivedType", derived_type)
self.assertIn(f'name: "{field}"', derived_type)
base_type_match = base_type_matcher.match(derived_type)
base_type_matches = base_type_match.groups()
self.assertEqual(len(base_type_matches), 1)
base_type_marker = base_type_matches[0]
data_type = metadata_definition_map[base_type_marker]
self.assertRegex(data_type, expected[field])
def test_debug_optnone(self):
def get_debug_lines(fn):
metadata = self._get_metadata(fn, fn.signatures[0])
lines = self._get_lines_from_debuginfo(metadata)
return lines
def get_func_attrs(fn):
cres = fn.overloads[fn.signatures[0]]
lib = cres.library
fn = lib._final_module.get_function(cres.fndesc.mangled_name)
attrs = set(b' '.join(fn.attributes).split())
return attrs
def foo():
n = 10
c = 0
for i in range(n):
c += i
return c
foo_debug = njit(debug=True)(foo)
foo_debug_optnone = njit(debug=True, _dbg_optnone=True)(foo)
foo_debug_optnone_inline = njit(debug=True, _dbg_optnone=True,
forceinline=True)(foo)
firstline = foo.__code__.co_firstlineno
expected_info = {}
expected_info[foo_debug] = dict(
# just the dummy line-0 and the line of the return statement
lines={0, firstline + 5},
must_have_attrs=set(),
must_not_have_attrs=set([b"optnone"]),
)
expected_info[foo_debug_optnone] = dict(
# all the lines should be included
lines=set(range(firstline + 1, firstline + 6)),
must_have_attrs=set([b"optnone"]),
must_not_have_attrs=set(),
)
expected_info[foo_debug_optnone_inline] = dict(
# optnone=True is overridden by forceinline, so this looks like the
# foo_debug version
lines={0, firstline + 5},
must_have_attrs=set([b"alwaysinline"]),
must_not_have_attrs=set([b"optnone"]),
)
expected_ret = foo()
for udt, expected in expected_info.items():
with self.subTest(udt.targetoptions):
got = udt()
self.assertEqual(got, expected_ret)
# Compare the line locations in the debug info.
self.assertEqual(get_debug_lines(udt), expected["lines"])
# Check for attributes on the LLVM function
attrs = get_func_attrs(udt)
must_have = expected["must_have_attrs"]
self.assertEqual(attrs & must_have, must_have)
must_not_have = expected["must_not_have_attrs"]
self.assertFalse(attrs & must_not_have)
def test_omitted_arg(self):
# See issue 7726
@njit(debug=True)
def foo(missing=None):
pass
# check that it will actually compile (verifies DI emission is ok)
with override_config('DEBUGINFO_DEFAULT', 1):
foo()
metadata = self._get_metadata(foo, sig=(types.Omitted(None),))
metadata_definition_map = self._get_metadata_map(metadata)
# Find DISubroutineType
tmp_disubr = []
for md in metadata:
if "DISubroutineType" in md:
tmp_disubr.append(md)
self.assertEqual(len(tmp_disubr), 1)
disubr = tmp_disubr.pop()
disubr_matched = re.match(r'.*!DISubroutineType\(types: ([!0-9]+)\)$',
disubr)
self.assertIsNotNone(disubr_matched)
disubr_groups = disubr_matched.groups()
self.assertEqual(len(disubr_groups), 1)
disubr_meta = disubr_groups[0]
# Find the types in the DISubroutineType arg list
disubr_types = metadata_definition_map[disubr_meta]
disubr_types_matched = re.match(r'!{(.*)}', disubr_types)
self.assertIsNotNone(disubr_matched)
disubr_types_groups = disubr_types_matched.groups()
self.assertEqual(len(disubr_types_groups), 1)
# fetch out and assert the last argument type, should be void *
md_fn_arg = [x.strip() for x in disubr_types_groups[0].split(',')][-1]
arg_ty = metadata_definition_map[md_fn_arg]
expected_arg_ty = (r'^.*!DICompositeType\(tag: DW_TAG_structure_type, '
r'name: "Anonymous struct \({}\)", elements: '
r'(![0-9]+), identifier: "{}"\)')
self.assertRegex(arg_ty, expected_arg_ty)
md_base_ty = re.match(expected_arg_ty, arg_ty).groups()[0]
base_ty = metadata_definition_map[md_base_ty]
# expect ir.LiteralStructType([])
self.assertEqual(base_ty, ('!{}'))
def test_missing_source(self):
strsrc = """
def foo():
return 1
"""
l = dict()
exec(dedent(strsrc), {}, l)
foo = njit(debug=True)(l['foo'])
with warnings.catch_warnings(record=True) as w:
warnings.simplefilter('always', NumbaDebugInfoWarning)
ignore_internal_warnings()
foo()
self.assertEqual(len(w), 1)
found = w[0]
self.assertEqual(found.category, NumbaDebugInfoWarning)
msg = str(found.message)
# make sure the warning contains the right message
self.assertIn('Could not find source for function', msg)
# and refers to the offending function
self.assertIn(str(foo.py_func), msg)
def test_irregularly_indented_source(self):
@njit(debug=True)
def foo():
# NOTE: THIS COMMENT MUST START AT COLUMN 0 FOR THIS SAMPLE CODE TO BE VALID # noqa: E115, E501
return 1
with warnings.catch_warnings(record=True) as w:
warnings.simplefilter('always', NumbaDebugInfoWarning)
ignore_internal_warnings()
foo()
# No warnings
self.assertEqual(len(w), 0)
metadata = self._get_metadata(foo, foo.signatures[0])
lines = self._get_lines_from_debuginfo(metadata)
# Only one line
self.assertEqual(len(lines), 1)
if __name__ == '__main__':
unittest.main()