Fixes for lineinfo emission

[stuartarchibald]

As title.

Includes: 2d63784 from #7177 as 3631bdb

[sklam]

I can confirm that the decref is no longer jumping back to the line of object creation. I used the following code to test the decref DWARF info:

@njit(debug=True)
def foo(n):
    #gdb()
    ar = np.arange(n)
    if ar.sum() == 0:    # lifetime of ar ends after this line
        ret = 2
    else:
        ret = 3
    return ret

[stuartarchibald]

@sklam thanks for checking. I've patched the disassembly support here: stuartarchibald@ee91dd8 to include DWARF info in the disassembly CFG.

[sklam]

Cool, i'll try it now

[sklam]

a duplication of

numba/numba/tests/test_parfors.py

Lines 73 to 86 in 0c499bf

	def runner(self):
	themod = self.__module__
	test_clazz_name = self.id().split('.')[-1].split('_')[-1]
	the_test = f'{themod}.{test_clazz_name}'
	cmd = [sys.executable, '-m', 'numba.runtests', the_test]
	env_copy = os.environ.copy()
	env_copy['SUBPROC_TEST'] = '1'
	status = subprocess.run(cmd, stdout=subprocess.PIPE,
	stderr=subprocess.PIPE, timeout=self._TIMEOUT,
	env=env_copy, universal_newlines=True)
	self.assertEqual(status.returncode, 0, msg=status.stderr)
	self.assertIn('OK', status.stderr)
	self.assertTrue('FAIL' not in status.stderr)
	self.assertTrue('ERROR' not in status.stderr)

we should dedup here or in a immediate follow up PR

[sklam]

There's still a copy of this in test_parfors.py

numba/numba/tests/test_parfors.py

Lines 56 to 57 in 2eacea6

	_exec_cond = os.environ.get('SUBPROC_TEST', None) == '1'
	needs_subprocess = unittest.skipUnless(_exec_cond, "needs subprocess harness")

[sklam]

Suggested change

	self.assertTrue('FAIL' not in status.stderr)
	self.assertNotIn('FAIL', status.stderr)

[sklam]

Suggested change

	self.assertTrue('ERROR' not in status.stderr)
	self.assertNotIn('ERROR', status.stderr)

[sklam]

Suggested change

	self.assertTrue(count > 0) # make sure there were some decrefs!
	self.assertGreater(count, 0) # make sure there were some decrefs!

[sklam]

Suggested change

	# make sure decref lines end with `meminfo.<number>)`.
	# make sure decref lines end with `meminfo.<number>)` without dbg info.

[sklam]

I wonder if we should leave a note about how the tests are sensitive to SSA and lowering behavior such that they may become outdated when those are changed.

[stuartarchibald]

I wonder if we should leave a note about how the tests are sensitive to SSA and lowering behavior such that they may become outdated when those are changed.

Good point, I've added one as part of 8f1c198. All other comments should be addressed in there too. Thanks for the review.

[sklam]

Thanks for the patch!