FYI: TRY_CATCH audit for python

[Tom Tromey <tromey at redhat dot com>]

I'm checking this in.

After my patch the other day it occurred to me that perhaps the
TRY_CATCH bug lurked elsewhere in the Python code.

I audited all the TRY_CATCH uses in python/*.c.  I found one cleanup
bug, and one spot where moving a declaration could make the code easier
to understand.  I also fixed a missing error check in the function with
the bad cleanup use.

Built and regtested on x86-64 F16.

Tom

2012-03-30  Tom Tromey  <tromey@redhat.com>

	* python/python.c (gdbpy_decode_line): Move cleanup creation out
	of TRY_CATCH.  Fix error handling.
	* python/py-value.c (convert_value_from_python): Move 'old'
	declaration to innermost scope.

Index: python/py-value.c
===================================================================
RCS file: /cvs/src/src/gdb/python/py-value.c,v
retrieving revision 1.35
diff -u -r1.35 py-value.c
--- python/py-value.c	22 Mar 2012 08:10:44 -0000	1.35
+++ python/py-value.c	30 Mar 2012 20:04:32 -0000
@@ -1250,7 +1250,6 @@
 convert_value_from_python (PyObject *obj)
 {
   struct value *value = NULL; /* -Wall */
-  struct cleanup *old;
   volatile struct gdb_exception except;
   int cmp;
 
@@ -1319,6 +1318,8 @@
 	  s = python_string_to_target_string (obj);
 	  if (s != NULL)
 	    {
+	      struct cleanup *old;
+
 	      old = make_cleanup (xfree, s);
 	      value = value_cstring (s, strlen (s), builtin_type_pychar);
 	      do_cleanups (old);
Index: python/python.c
===================================================================
RCS file: /cvs/src/src/gdb/python/python.c,v
retrieving revision 1.85
diff -u -r1.85 python.c
--- python/python.c	28 Jan 2012 18:08:22 -0000	1.85
+++ python/python.c	30 Mar 2012 20:04:32 -0000
@@ -503,7 +503,7 @@
 						  appease gcc.  */
   struct symtab_and_line sal;
   const char *arg = NULL;
-  char *copy = NULL;
+  char *copy_to_free = NULL, *copy = NULL;
   struct cleanup *cleanups;
   PyObject *result = NULL;
   PyObject *return_result = NULL;
@@ -515,14 +515,14 @@
 
   cleanups = make_cleanup (null_cleanup, NULL);
 
+  sals.sals = NULL;
   TRY_CATCH (except, RETURN_MASK_ALL)
     {
       if (arg)
 	{
 	  copy = xstrdup (arg);
-	  make_cleanup (xfree, copy);
+	  copy_to_free = copy;
 	  sals = decode_line_1 (&copy, 0, 0, 0);
-	  make_cleanup (xfree, sals.sals);
 	}
       else
 	{
@@ -532,6 +532,13 @@
 	  sals.nelts = 1;
 	}
     }
+
+  if (sals.sals != NULL && sals.sals != &sal)
+    {
+      make_cleanup (xfree, copy_to_free);
+      make_cleanup (xfree, sals.sals);
+    }
+
   if (except.reason < 0)
     {
       do_cleanups (cleanups);
@@ -575,7 +582,16 @@
     }
 
   if (copy && strlen (copy) > 0)
-    unparsed = PyString_FromString (copy);
+    {
+      unparsed = PyString_FromString (copy);
+      if (unparsed == NULL)
+	{
+	  Py_DECREF (result);
+	  Py_DECREF (return_result);
+	  return_result = NULL;
+	  goto error;
+	}
+    }
   else
     {
       unparsed = Py_None;
@@ -585,13 +601,10 @@
   PyTuple_SetItem (return_result, 0, unparsed);
   PyTuple_SetItem (return_result, 1, result);
 
+ error:
   do_cleanups (cleanups);
 
   return return_result;
-
- error:
-  do_cleanups (cleanups);
-  return NULL;
 }
 
 /* Parse a string and evaluate it as an expression.  */