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Fix for bug 133489: compiler leaks memory 

Two different but related problems:

1. PySymtable_Free() must explicitly DECREF(st->st_cur), which should
always point to the global symtable entry.  This entry is setup by the
first enter_scope() call, but there is never a corresponding
exit_scope() call.

Since each entry has a reference to scopes defined within it, the
missing DECREF caused all symtable entries to be leaked.

2. The leak here masked a separate problem with
PySymtableEntry_New().  When the requested entry was found in
st->st_symbols, the entry was returned without doing an INCREF.

And problem c) The ste_children slot was getting two copies of each
child entry, because it was populating the slot on the first and
second passes.  Now only populate on the first pass.
This commit is contained in:
Jeremy Hylton 2001-02-23 17:55:27 +00:00
parent 3e13b1e48b
commit 74b3bc47df
2 changed files with 11 additions and 5 deletions
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8
Python/compile.c
View File

@ -3912,8 +3912,10 @@ jcompile(node *n, char *filename, struct compiling *base)
PyErr_SetString(PyExc_SystemError, "lost syntax error");
}
exit:
if (base == NULL)
if (base == NULL) {
PySymtable_Free(sc.c_symtable);
sc.c_symtable = NULL;
}
com_free(&sc);
return co;
}
@ -4193,6 +4195,7 @@ PySymtable_Free(struct symtable *st)
{
Py_XDECREF(st->st_symbols);
Py_XDECREF(st->st_stack);
Py_XDECREF(st->st_cur);
PyMem_Free((void *)st);
}
@ -4359,10 +4362,11 @@ symtable_enter_scope(struct symtable *st, char *name, int type,
PySymtableEntry_New(st, name, type, lineno);
if (strcmp(name, TOP) == 0)
st->st_global = st->st_cur->ste_symbols;
if (prev)
if (prev && st->st_pass == 1) {
if (PyList_Append(prev->ste_children,
(PyObject *)st->st_cur) < 0)
st->st_errors++;
}
}
static int

8
Python/symtable.c
View File

@ -13,8 +13,10 @@ PySymtableEntry_New(struct symtable *st, char *name, int type, int lineno)
if (k == NULL)
goto fail;
v = PyDict_GetItem(st->st_symbols, k);
if (v) /* XXX could check that name, type, lineno match */
return v;
if (v) /* XXX could check that name, type, lineno match */ {
Py_INCREF(v);
return v;
}
ste = (PySymtableEntryObject *)PyObject_New(PySymtableEntryObject,
&PySymtableEntry_Type);
@ -69,7 +71,7 @@ PySymtableEntry_New(struct symtable *st, char *name, int type, int lineno)
if (PyDict_SetItem(st->st_symbols, ste->ste_id, (PyObject *)ste) < 0)
goto fail;
return (PyObject *)ste;
fail:
Py_XDECREF(ste);