From 3325a6780c81f1ea51190370b5454879c4862a37 Mon Sep 17 00:00:00 2001 From: Serhiy Storchaka Date: Fri, 15 Dec 2017 12:35:48 +0200 Subject: [PATCH] bpo-27169: The __debug__ constant is now optimized out at compile time. (#4880) This fixes also bpo-22091. --- Lib/test/test_builtin.py | 16 +++---- Lib/test/test_compile.py | 1 + .../2017-12-15-11-50-06.bpo-27169.VO84fQ.rst | 2 + Python/compile.c | 45 +++++++------------ 4 files changed, 26 insertions(+), 38 deletions(-) create mode 100644 Misc/NEWS.d/next/Core and Builtins/2017-12-15-11-50-06.bpo-27169.VO84fQ.rst diff --git a/Lib/test/test_builtin.py b/Lib/test/test_builtin.py index 9329318706b..8f91bc9bf91 100644 --- a/Lib/test/test_builtin.py +++ b/Lib/test/test_builtin.py @@ -337,16 +337,16 @@ class BuiltinTest(unittest.TestCase): try: assert False except AssertionError: - return (True, f.__doc__, debug_enabled) + return (True, f.__doc__, debug_enabled, __debug__) else: - return (False, f.__doc__, debug_enabled) + return (False, f.__doc__, debug_enabled, __debug__) ''' def f(): """doc""" - values = [(-1, __debug__, f.__doc__, __debug__), - (0, True, 'doc', True), - (1, False, 'doc', False), - (2, False, None, False)] - for optval, assertval, docstring, debugval in values: + values = [(-1, __debug__, f.__doc__, __debug__, __debug__), + (0, True, 'doc', True, True), + (1, False, 'doc', False, False), + (2, False, None, False, False)] + for optval, *expected in values: # test both direct compilation and compilation via AST codeobjs = [] codeobjs.append(compile(codestr, "", "exec", optimize=optval)) @@ -356,7 +356,7 @@ class BuiltinTest(unittest.TestCase): ns = {} exec(code, ns) rv = ns['f']() - self.assertEqual(rv, (assertval, docstring, debugval)) + self.assertEqual(rv, tuple(expected)) def test_delattr(self): sys.spam = 1 diff --git a/Lib/test/test_compile.py b/Lib/test/test_compile.py index b4a52a53105..ae3043af0bd 100644 --- a/Lib/test/test_compile.py +++ b/Lib/test/test_compile.py @@ -35,6 +35,7 @@ class TestSpecifics(unittest.TestCase): import builtins prev = builtins.__debug__ setattr(builtins, '__debug__', 'sure') + self.assertEqual(__debug__, prev) setattr(builtins, '__debug__', prev) def test_argument_handling(self): diff --git a/Misc/NEWS.d/next/Core and Builtins/2017-12-15-11-50-06.bpo-27169.VO84fQ.rst b/Misc/NEWS.d/next/Core and Builtins/2017-12-15-11-50-06.bpo-27169.VO84fQ.rst new file mode 100644 index 00000000000..81d1d15cbbd --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2017-12-15-11-50-06.bpo-27169.VO84fQ.rst @@ -0,0 +1,2 @@ +The ``__debug__`` constant is now optimized out at compile time. This fixes also +bpo-22091. diff --git a/Python/compile.c b/Python/compile.c index 3fd849108cc..51c9a08162c 100644 --- a/Python/compile.c +++ b/Python/compile.c @@ -1332,13 +1332,15 @@ is_const(expr_ty e) case Ellipsis_kind: case NameConstant_kind: return 1; + case Name_kind: + return _PyUnicode_EqualToASCIIString(e->v.Name.id, "__debug__"); default: return 0; } } static PyObject * -get_const_value(expr_ty e) +get_const_value(struct compiler *c, expr_ty e) { switch (e->kind) { case Constant_kind: @@ -1353,6 +1355,9 @@ get_const_value(expr_ty e) return Py_Ellipsis; case NameConstant_kind: return e->v.NameConstant.value; + case Name_kind: + assert(_PyUnicode_EqualToASCIIString(e->v.Name.id, "__debug__")); + return c->c_optimize ? Py_False : Py_True; default: Py_UNREACHABLE(); } @@ -3097,6 +3102,11 @@ compiler_nameop(struct compiler *c, identifier name, expr_context_ty ctx) !_PyUnicode_EqualToASCIIString(name, "True") && !_PyUnicode_EqualToASCIIString(name, "False")); + if (ctx == Load && _PyUnicode_EqualToASCIIString(name, "__debug__")) { + ADDOP_O(c, LOAD_CONST, c->c_optimize ? Py_False : Py_True, consts); + return 1; + } + op = 0; optype = OP_NAME; scope = PyST_GetScope(c->u->u_ste, mangled); @@ -3360,7 +3370,7 @@ compiler_subdict(struct compiler *c, expr_ty e, Py_ssize_t begin, Py_ssize_t end return 0; } for (i = begin; i < end; i++) { - key = get_const_value((expr_ty)asdl_seq_GET(e->v.Dict.keys, i)); + key = get_const_value(c, (expr_ty)asdl_seq_GET(e->v.Dict.keys, i)); Py_INCREF(key); PyTuple_SET_ITEM(keys, i - begin, key); } @@ -4132,35 +4142,10 @@ compiler_visit_keyword(struct compiler *c, keyword_ty k) static int expr_constant(struct compiler *c, expr_ty e) { - const char *id; - switch (e->kind) { - case Ellipsis_kind: - return 1; - case Constant_kind: - return PyObject_IsTrue(e->v.Constant.value); - case Num_kind: - return PyObject_IsTrue(e->v.Num.n); - case Str_kind: - return PyObject_IsTrue(e->v.Str.s); - case Name_kind: - /* optimize away names that can't be reassigned */ - id = PyUnicode_AsUTF8(e->v.Name.id); - if (id && strcmp(id, "__debug__") == 0) - return !c->c_optimize; - return -1; - case NameConstant_kind: { - PyObject *o = e->v.NameConstant.value; - if (o == Py_None) - return 0; - else if (o == Py_True) - return 1; - else if (o == Py_False) - return 0; - } - /* fall through */ - default: - return -1; + if (is_const(e)) { + return PyObject_IsTrue(get_const_value(c, e)); } + return -1; }