by ``CALL_FUNCTION`` to construct a class.
+.. 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. TOS is
#. 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
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.
+ 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 6 below.
#. The suite is executed.
#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 144
#define LIST_APPEND 145
#define SET_ADD 146
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('LIST_APPEND', 145)
def_op('SET_ADD', 146)
def_op('MAP_ADD', 147)
+def_op('EXTENDED_ARG', 144)
+EXTENDED_ARG = 144
del def_op, name_op, jrel_op, jabs_op
def some_number(self_, key):
self.assertEqual(key, "hi")
return 4
+ 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
set(("__class__",)), {}),
("__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):
static void format_exc_check_arg(PyObject *, const char *, PyObject *);
static PyObject * unicode_concatenate(PyObject *, PyObject *,
PyFrameObject *, unsigned char *);
+static PyObject * special_lookup(PyObject *, char *, PyObject **);
#define NAME_ERROR_MSG \
"name '%.200s' is not defined"
STACK_LEVEL());
DISPATCH();
+ TARGET(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);
+ DISPATCH();
+ }
+
TARGET(WITH_CLEANUP)
{
/* At the top of the stack are 1-3 values indicating
should still be resumed.)
*/
- PyObject *exit_func = POP();
+ PyObject *exit_func;
u = TOP();
if (u == Py_None) {
+ POP();
+ exit_func = TOP();
+ SET_TOP(u);
v = w = Py_None;
}
else if (PyLong_Check(u)) {
+ POP();
+ switch(PyLong_AsLong(u)) {
+ case WHY_RETURN:
+ case WHY_CONTINUE:
+ /* Retval in TOP. */
+ exit_func = SECOND();
+ SET_SECOND(TOP());
+ SET_TOP(u);
+ break;
+ default:
+ exit_func = TOP();
+ SET_TOP(u);
+ break;
+ }
u = v = w = Py_None;
}
else {
- v = SECOND();
+ v = SECOND();
w = THIRD();
+ exit_func = stack_pointer[-7];
+ stack_pointer[-7] = NULL;
}
/* XXX Not the fastest way to call it... */
x = PyObject_CallFunctionObjArgs(exit_func, u, v, w,
else if (err > 0) {
err = 0;
/* There was an exception and a True return */
- STACKADJ(-2);
- SET_TOP(PyLong_FromLong((long) WHY_SILENCED));
- Py_DECREF(u);
- Py_DECREF(v);
- Py_DECREF(w);
+ PUSH(PyLong_FromLong((long) WHY_SILENCED));
}
PREDICT(END_FINALLY);
break;
}
+static PyObject *
+special_lookup(PyObject *o, char *meth, PyObject **cache)
+{
+ PyObject *res;
+ res = _PyObject_LookupSpecial(o, meth, cache);
+ if (res == NULL && !PyErr_Occurred()) {
+ PyErr_SetObject(PyExc_AttributeError, *cache);
+ return NULL;
+ }
+ return res;
+}
+
+
/* Logic for the raise statement (too complicated for inlining).
This *consumes* a reference count to each of its arguments. */
static enum why_code
return -1;
case BREAK_LOOP:
return 0;
+ case SETUP_WITH:
+ return 7;
case WITH_CLEANUP:
return -1; /* XXX Sometimes more */
case STORE_LOCALS:
static int
compiler_with(struct compiler *c, stmt_ty s)
{
- static identifier enter_attr, exit_attr;
basicblock *block, *finally;
- identifier tmpvalue = NULL, tmpexit = NULL;
assert(s->kind == With_kind);
- if (!enter_attr) {
- enter_attr = PyUnicode_InternFromString("__enter__");
- if (!enter_attr)
- return 0;
- }
- if (!exit_attr) {
- exit_attr = PyUnicode_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);
- }
- tmpexit = compiler_new_tmpname(c);
- if (tmpexit == NULL)
- return 0;
- PyArena_AddPyObject(c->c_arena, tmpexit);
-
/* 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);
- if (!compiler_nameop(c, tmpexit, Store))
- return 0;
-
- /* 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 */
/* Finally block starts; context.__exit__ is on the stack under
the exception or return information. Just issue our magic
opcode. */
- if (!compiler_nameop(c, tmpexit, Load) ||
- !compiler_nameop(c, tmpexit, Del))
- return 0;
ADDOP(c, WITH_CLEANUP);
/* Finally block ends. */
change LIST_APPEND and SET_ADD, add MAP_ADD)
Python 3.1a0: 3150 (optimize conditional branches:
introduce POP_JUMP_IF_FALSE and POP_JUMP_IF_TRUE)
+ Python 3.2a0: 3160 (add SETUP_WITH)
*/
-#define MAGIC (3150 | ((long)'\r'<<16) | ((long)'\n'<<24))
+#define MAGIC (3160 | ((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
compiler works which are enabled by command line switches. */
&&TARGET_CALL_FUNCTION_VAR,
&&TARGET_CALL_FUNCTION_KW,
&&TARGET_CALL_FUNCTION_VAR_KW,
+ &&TARGET_SETUP_WITH,
&&TARGET_EXTENDED_ARG,
- &&_unknown_opcode,
&&TARGET_LIST_APPEND,
&&TARGET_SET_ADD,
&&TARGET_MAP_ADD,
case SETUP_LOOP:
case SETUP_EXCEPT:
case SETUP_FINALLY:
+ case SETUP_WITH:
j = GETJUMPTGT(code, i);
blocks[j] = 1;
break;
case SETUP_LOOP:
case SETUP_EXCEPT:
case SETUP_FINALLY:
+ case SETUP_WITH:
tgt = GETJUMPTGT(codestr, i);
/* Replace JUMP_* to a RETURN into just a RETURN */
if (UNCONDITIONAL_JUMP(opcode) &&
case SETUP_LOOP:
case SETUP_EXCEPT:
case SETUP_FINALLY:
+ case SETUP_WITH:
j = addrmap[GETARG(codestr, i) + i + 3] - addrmap[i] - 3;
SETARG(codestr, i, j);
break;
projects / python / commitdiff