diff options
| -rw-r--r-- | Doc/library/dis.rst | 12 | ||||
| -rw-r--r-- | Doc/reference/compound_stmts.rst | 4 | ||||
| -rw-r--r-- | Include/opcode.h | 4 | ||||
| -rw-r--r-- | Lib/opcode.py | 7 | ||||
| -rw-r--r-- | Lib/test/test_descr.py | 8 | ||||
| -rw-r--r-- | Misc/NEWS | 3 | ||||
| -rw-r--r-- | Python/ceval.c | 46 | ||||
| -rw-r--r-- | Python/compile.c | 65 | ||||
| -rw-r--r-- | Python/import.c | 3 |
9 files changed, 86 insertions, 66 deletions
diff --git a/Doc/library/dis.rst b/Doc/library/dis.rst index 6b7ed1e..9bd65dd 100644 --- a/Doc/library/dis.rst +++ b/Doc/library/dis.rst @@ -532,6 +532,18 @@ Miscellaneous opcodes. the names of the base classes, and TOS2 the class name. +.. opcode:: SETUP_WITH (delta) + + This opcode performs several operations before a with block starts. First, + it loads :meth:`~object.__exit__` from the context manager and pushes it onto + the stack for later use by :opcode:`WITH_CLEANUP`. Then, + :meth:`~object.__enter__` is called, and a finally block pointing to *delta* + is pushed. Finally, the result of calling the enter method is pushed onto + the stack. The next opcode will either ignore it (:opcode:`POP_TOP`), or + store it in (a) variable(s) (:opcode:`STORE_FAST`, :opcode:`STORE_NAME`, or + :opcode:`UNPACK_SEQUENCE`). + + .. opcode:: WITH_CLEANUP () Cleans up the stack when a :keyword:`with` statement block exits. On top of diff --git a/Doc/reference/compound_stmts.rst b/Doc/reference/compound_stmts.rst index 3c716b2..afb7ebc 100644 --- a/Doc/reference/compound_stmts.rst +++ b/Doc/reference/compound_stmts.rst @@ -339,6 +339,8 @@ The execution of the :keyword:`with` statement proceeds as follows: #. The context expression is evaluated to obtain a context manager. +#. The context manager's :meth:`__exit__` is loaded for later use. + #. The context manager's :meth:`__enter__` method is invoked. #. If a target was included in the :keyword:`with` statement, the return value @@ -349,7 +351,7 @@ The execution of the :keyword:`with` statement proceeds as follows: The :keyword:`with` statement guarantees that if the :meth:`__enter__` method returns without an error, then :meth:`__exit__` will always be called. Thus, if an error occurs during the assignment to the target list, it will be treated the - same as an error occurring within the suite would be. See step 5 below. + same as an error occurring within the suite would be. See step 6 below. #. The suite is executed. diff --git a/Include/opcode.h b/Include/opcode.h index 36a35dc..9739782 100644 --- a/Include/opcode.h +++ b/Include/opcode.h @@ -141,8 +141,10 @@ extern "C" { #define CALL_FUNCTION_KW 141 /* #args + (#kwargs<<8) */ #define CALL_FUNCTION_VAR_KW 142 /* #args + (#kwargs<<8) */ +#define SETUP_WITH 143 + /* Support for opargs more than 16 bits long */ -#define EXTENDED_ARG 143 +#define EXTENDED_ARG 145 enum cmp_op {PyCmp_LT=Py_LT, PyCmp_LE=Py_LE, PyCmp_EQ=Py_EQ, PyCmp_NE=Py_NE, PyCmp_GT=Py_GT, PyCmp_GE=Py_GE, diff --git a/Lib/opcode.py b/Lib/opcode.py index 24d5dcc..7c3962d 100644 --- a/Lib/opcode.py +++ b/Lib/opcode.py @@ -181,7 +181,10 @@ hasfree.append(137) def_op('CALL_FUNCTION_VAR', 140) # #args + (#kwargs << 8) def_op('CALL_FUNCTION_KW', 141) # #args + (#kwargs << 8) def_op('CALL_FUNCTION_VAR_KW', 142) # #args + (#kwargs << 8) -def_op('EXTENDED_ARG', 143) -EXTENDED_ARG = 143 + +jrel_op('SETUP_WITH', 143) + +def_op('EXTENDED_ARG', 145) +EXTENDED_ARG = 145 del def_op, name_op, jrel_op, jabs_op diff --git a/Lib/test/test_descr.py b/Lib/test/test_descr.py index c7989b1..627f8aa 100644 --- a/Lib/test/test_descr.py +++ b/Lib/test/test_descr.py @@ -1689,6 +1689,7 @@ order (MRO) for bases """ return isinstance(int, obj) def do_issubclass(obj): return issubclass(int, obj) + def swallow(*args): pass # It would be nice to have every special method tested here, but I'm # only listing the ones I can remember outside of typeobject.c, since it @@ -1702,11 +1703,8 @@ order (MRO) for bases """ ("__instancecheck__", do_isinstance, return_true, set(), {}), ("__subclasscheck__", do_issubclass, return_true, set(("__bases__",)), {}), - # These two fail because the compiler generates LOAD_ATTR to look - # them up. We'd have to add a new opcode to fix this, and it's - # probably not worth it. - # ("__enter__", run_context, iden), - # ("__exit__", run_context, iden), + ("__enter__", run_context, iden, set(), {"__exit__" : swallow}), + ("__exit__", run_context, swallow, set(), {"__enter__" : iden}), ] class Checker(object): @@ -12,6 +12,9 @@ What's New in Python 2.7 alpha 1 Core and Builtins ----------------- +- Issue #6101: A new opcode, SETUP_WITH, has been added to speed up the with + statement and correctly lookup the __enter__ and __exit__ special methods. + - Issue #5829: complex("1e500") no longer raises OverflowError. This makes it consistent with float("1e500") and interpretation of real and imaginary literals. diff --git a/Python/ceval.c b/Python/ceval.c index 4f0877b..92021e6 100644 --- a/Python/ceval.c +++ b/Python/ceval.c @@ -128,6 +128,7 @@ static void format_exc_check_arg(PyObject *, char *, PyObject *); static PyObject * string_concatenate(PyObject *, PyObject *, PyFrameObject *, unsigned char *); static PyObject * kwd_as_string(PyObject *); +static PyObject * special_lookup(PyObject *, char *, PyObject **); #define NAME_ERROR_MSG \ "name '%.200s' is not defined" @@ -2467,6 +2468,33 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag) STACK_LEVEL()); continue; + case SETUP_WITH: + { + static PyObject *exit, *enter; + w = TOP(); + x = special_lookup(w, "__exit__", &exit); + if (!x) + break; + SET_TOP(x); + u = special_lookup(w, "__enter__", &enter); + Py_DECREF(w); + if (!u) { + x = NULL; + break; + } + x = PyObject_CallFunctionObjArgs(u, NULL); + Py_DECREF(u); + if (!x) + break; + /* Setup the finally block before pushing the result + of __enter__ on the stack. */ + PyFrame_BlockSetup(f, SETUP_FINALLY, INSTR_OFFSET() + oparg, + STACK_LEVEL()); + + PUSH(x); + continue; + } + case WITH_CLEANUP: { /* At the top of the stack are 1-3 values indicating @@ -3171,6 +3199,24 @@ fail: /* Jump here from prelude on failure */ } +static PyObject * +special_lookup(PyObject *o, char *meth, PyObject **cache) +{ + PyObject *res; + if (PyInstance_Check(o)) { + if (!*cache) + return PyObject_GetAttrString(o, meth); + else + return PyObject_GetAttr(o, *cache); + } + res = _PyObject_LookupSpecial(o, meth, cache); + if (res == NULL && !PyErr_Occurred()) { + PyErr_SetObject(PyExc_AttributeError, *cache); + return NULL; + } + return res; +} + static PyObject * kwd_as_string(PyObject *kwd) { diff --git a/Python/compile.c b/Python/compile.c index 8c85306..e263d76 100644 --- a/Python/compile.c +++ b/Python/compile.c @@ -778,6 +778,8 @@ opcode_stack_effect(int opcode, int oparg) return -1; case BREAK_LOOP: return 0; + case SETUP_WITH: + return 1; case WITH_CLEANUP: return -1; /* XXX Sometimes more */ case LOAD_LOCALS: @@ -2821,80 +2823,31 @@ expr_constant(expr_ty e) static int compiler_with(struct compiler *c, stmt_ty s) { - static identifier enter_attr, exit_attr; basicblock *block, *finally; - identifier tmpvalue = NULL; assert(s->kind == With_kind); - if (!enter_attr) { - enter_attr = PyString_InternFromString("__enter__"); - if (!enter_attr) - return 0; - } - if (!exit_attr) { - exit_attr = PyString_InternFromString("__exit__"); - if (!exit_attr) - return 0; - } - block = compiler_new_block(c); finally = compiler_new_block(c); if (!block || !finally) return 0; - if (s->v.With.optional_vars) { - /* Create a temporary variable to hold context.__enter__(). - We need to do this rather than preserving it on the stack - because SETUP_FINALLY remembers the stack level. - We need to do the assignment *inside* the try/finally - so that context.__exit__() is called when the assignment - fails. But we need to call context.__enter__() *before* - the try/finally so that if it fails we won't call - context.__exit__(). - */ - tmpvalue = compiler_new_tmpname(c); - if (tmpvalue == NULL) - return 0; - PyArena_AddPyObject(c->c_arena, tmpvalue); - } - /* Evaluate EXPR */ VISIT(c, expr, s->v.With.context_expr); + ADDOP_JREL(c, SETUP_WITH, finally); - /* Squirrel away context.__exit__ by stuffing it under context */ - ADDOP(c, DUP_TOP); - ADDOP_O(c, LOAD_ATTR, exit_attr, names); - ADDOP(c, ROT_TWO); - - /* Call context.__enter__() */ - ADDOP_O(c, LOAD_ATTR, enter_attr, names); - ADDOP_I(c, CALL_FUNCTION, 0); - - if (s->v.With.optional_vars) { - /* Store it in tmpvalue */ - if (!compiler_nameop(c, tmpvalue, Store)) - return 0; - } - else { - /* Discard result from context.__enter__() */ - ADDOP(c, POP_TOP); - } - - /* Start the try block */ - ADDOP_JREL(c, SETUP_FINALLY, finally); - + /* SETUP_WITH pushes a finally block. */ compiler_use_next_block(c, block); if (!compiler_push_fblock(c, FINALLY_TRY, block)) { return 0; } if (s->v.With.optional_vars) { - /* Bind saved result of context.__enter__() to VAR */ - if (!compiler_nameop(c, tmpvalue, Load) || - !compiler_nameop(c, tmpvalue, Del)) - return 0; - VISIT(c, expr, s->v.With.optional_vars); + VISIT(c, expr, s->v.With.optional_vars); + } + else { + /* Discard result from context.__enter__() */ + ADDOP(c, POP_TOP); } /* BLOCK code */ diff --git a/Python/import.c b/Python/import.c index 5e42e5c..88aced0 100644 --- a/Python/import.c +++ b/Python/import.c @@ -74,9 +74,10 @@ typedef unsigned short mode_t; Python 2.7a0: 62171 (optimize list comprehensions/change LIST_APPEND) Python 2.7a0: 62181 (optimize conditional branches: introduce POP_JUMP_IF_FALSE and POP_JUMP_IF_TRUE) + Python 2.7a0 62191 (introduce SETUP_WITH) . */ -#define MAGIC (62181 | ((long)'\r'<<16) | ((long)'\n'<<24)) +#define MAGIC (62191 | ((long)'\r'<<16) | ((long)'\n'<<24)) /* Magic word as global; note that _PyImport_Init() can change the value of this global to accommodate for alterations of how the |