[PATCH 13/28] fix get_addr_from_python

[Tom Tromey <tromey at redhat dot com>]

get_addr_from_python confused the checker and so I decided to change
it to a form that it found more palatable.  In particular now it
returns a negative value on error (using
CPYCHECKER_NEGATIVE_RESULT_SETS_EXCEPTION), and it can no longer throw
a gdb exception.  This let me hoist calls to it out of some
TRY_CATCHes.

	* python/py-inferior.c (gdbpy_inferiors): Update.  Hoist
	get_addr_from_python calls out of TRY_CATCH.
	(infpy_write_memory, infpy_search_memory): Likewise.
	* python/py-utils.c (get_addr_from_python): Return negative
	value on error.  Use TRY_CATCH.
	* python/python-internal.h (get_addr_from_python): Use
	CPYCHECKER_NEGATIVE_RESULT_SETS_EXCEPTION.
---
 gdb/python/py-inferior.c     | 103 ++++++++++++++++++-------------------------
 gdb/python/py-utils.c        |  21 ++++++---
 gdb/python/python-internal.h |   3 +-
 3 files changed, 59 insertions(+), 68 deletions(-)

diff --git a/gdb/python/py-inferior.c b/gdb/python/py-inferior.c
index d4ff90b..45b79ce 100644
--- a/gdb/python/py-inferior.c
+++ b/gdb/python/py-inferior.c
@@ -406,7 +406,6 @@ gdbpy_inferiors (PyObject *unused, PyObject *unused2)
 static PyObject *
 infpy_read_memory (PyObject *self, PyObject *args, PyObject *kw)
 {
-  int error = 0;
   CORE_ADDR addr, length;
   void *buffer = NULL;
   membuf_object *membuf_obj;
@@ -418,15 +417,12 @@ infpy_read_memory (PyObject *self, PyObject *args, PyObject *kw)
 				     &addr_obj, &length_obj))
     return NULL;
 
+  if (get_addr_from_python (addr_obj, &addr) < 0
+      || get_addr_from_python (length_obj, &length) < 0)
+    return NULL;
+
   TRY_CATCH (except, RETURN_MASK_ALL)
     {
-      if (!get_addr_from_python (addr_obj, &addr)
-	  || !get_addr_from_python (length_obj, &length))
-	{
-	  error = 1;
-	  break;
-	}
-
       buffer = xmalloc (length);
 
       read_memory (addr, buffer, length);
@@ -437,12 +433,6 @@ infpy_read_memory (PyObject *self, PyObject *args, PyObject *kw)
       GDB_PY_HANDLE_EXCEPTION (except);
     }
 
-  if (error)
-    {
-      xfree (buffer);
-      return NULL;
-    }
-
   membuf_obj = PyObject_New (membuf_object, &membuf_object_type);
   if (membuf_obj == NULL)
     {
@@ -477,7 +467,6 @@ static PyObject *
 infpy_write_memory (PyObject *self, PyObject *args, PyObject *kw)
 {
   Py_ssize_t buf_len;
-  int error = 0;
   const char *buffer;
   CORE_ADDR addr, length;
   PyObject *addr_obj, *length_obj = NULL;
@@ -500,21 +489,16 @@ infpy_write_memory (PyObject *self, PyObject *args, PyObject *kw)
     return NULL;
 #endif
 
+  if (get_addr_from_python (addr_obj, &addr) < 0)
+    goto fail;
+
+  if (!length_obj)
+    length = buf_len;
+  else if (get_addr_from_python (length_obj, &length) < 0)
+    goto fail;
+
   TRY_CATCH (except, RETURN_MASK_ALL)
     {
-      if (!get_addr_from_python (addr_obj, &addr))
-	{
-	  error = 1;
-	  break;
-	}
-
-      if (!length_obj)
-	length = buf_len;
-      else if (!get_addr_from_python (length_obj, &length))
-	{
-	  error = 1;
-	  break;
-	}
       write_memory_with_notification (addr, buffer, length);
     }
 #ifdef IS_PY3K
@@ -522,11 +506,13 @@ infpy_write_memory (PyObject *self, PyObject *args, PyObject *kw)
 #endif
   GDB_PY_HANDLE_EXCEPTION (except);
 
-
-  if (error)
-    return NULL;
-
   Py_RETURN_NONE;
+
+ fail:
+#ifdef IS_PY3K
+  PyBuffer_Release (&pybuf);
+#endif
+  return NULL;
 }
 
 /* Destructor of Membuf objects.  */
@@ -662,34 +648,26 @@ infpy_search_memory (PyObject *self, PyObject *args, PyObject *kw)
     return NULL;
 #endif
 
-  if (get_addr_from_python (start_addr_obj, &start_addr)
-      && get_addr_from_python (length_obj, &length))
-    {
-      if (!length)
-	{
-	  PyErr_SetString (PyExc_ValueError,
-			   _("Search range is empty."));
+  if (get_addr_from_python (start_addr_obj, &start_addr) < 0)
+    goto fail;
+ 
+  if (get_addr_from_python (length_obj, &length) < 0)
+    goto fail;
 
-#ifdef IS_PY3K
-	  PyBuffer_Release (&pybuf);
-#endif
-	  return NULL;
-	}
-      /* Watch for overflows.  */
-      else if (length > CORE_ADDR_MAX
-	       || (start_addr + length - 1) < start_addr)
-	{
-	  PyErr_SetString (PyExc_ValueError,
-			   _("The search range is too large."));
-
-#ifdef IS_PY3K
-	  PyBuffer_Release (&pybuf);
-#endif
-	  return NULL;
-	}
+  if (!length)
+    {
+      PyErr_SetString (PyExc_ValueError,
+		       _("Search range is empty."));
+      goto fail;
+    }
+  /* Watch for overflows.  */
+  else if (length > CORE_ADDR_MAX
+	   || (start_addr + length - 1) < start_addr)
+    {
+      PyErr_SetString (PyExc_ValueError,
+		       _("The search range is too large."));
+      goto fail;
     }
-  else
-    return NULL;
 
   TRY_CATCH (except, RETURN_MASK_ALL)
     {
@@ -697,16 +675,21 @@ infpy_search_memory (PyObject *self, PyObject *args, PyObject *kw)
 				    buffer, pattern_size,
 				    &found_addr);
     }
-  GDB_PY_HANDLE_EXCEPTION (except);
-
 #ifdef IS_PY3K
   PyBuffer_Release (&pybuf);
 #endif
+  GDB_PY_HANDLE_EXCEPTION (except);
 
   if (found)
     return PyLong_FromLong (found_addr);
   else
     Py_RETURN_NONE;
+
+ fail:
+#ifdef IS_PY3K
+  PyBuffer_Release (&pybuf);
+#endif
+  return NULL;
 }
 
 /* Implementation of gdb.Inferior.is_valid (self) -> Boolean.
diff --git a/gdb/python/py-utils.c b/gdb/python/py-utils.c
index 4cd35a0..6a7e9e4 100644
--- a/gdb/python/py-utils.c
+++ b/gdb/python/py-utils.c
@@ -291,39 +291,46 @@ gdbpy_convert_exception (struct gdb_exception exception)
 
 /* Converts OBJ to a CORE_ADDR value.
 
-   Returns 1 on success or 0 on failure, with a Python exception set.  This
-   function can also throw GDB exceptions.
+   Returns 0 on success or -1 on failure, with a Python exception set.
 */
 
 int
 get_addr_from_python (PyObject *obj, CORE_ADDR *addr)
 {
   if (gdbpy_is_value_object (obj))
-    *addr = value_as_address (value_object_to_value (obj));
+    {
+      volatile struct gdb_exception except;
+
+      TRY_CATCH (except, RETURN_MASK_ALL)
+	{
+	  *addr = value_as_address (value_object_to_value (obj));
+	}
+      GDB_PY_SET_HANDLE_EXCEPTION (except);
+    }
   else
     {
       PyObject *num = PyNumber_Long (obj);
       gdb_py_ulongest val;
 
       if (num == NULL)
-	return 0;
+	return -1;
 
       val = gdb_py_long_as_ulongest (num);
       Py_XDECREF (num);
       if (PyErr_Occurred ())
-	return 0;
+	return -1;
 
       if (sizeof (val) > sizeof (CORE_ADDR) && ((CORE_ADDR) val) != val)
 	{
 	  PyErr_SetString (PyExc_ValueError,
 			   _("Overflow converting to address."));
-	  return 0;
+	  return -1;
 	}
 
       *addr = val;
     }
 
-  return 1;
+  return 0;
 }
 
 /* Convert a LONGEST to the appropriate Python object -- either an
diff --git a/gdb/python/python-internal.h b/gdb/python/python-internal.h
index b887b66..5c3fe51 100644
--- a/gdb/python/python-internal.h
+++ b/gdb/python/python-internal.h
@@ -424,7 +424,8 @@ extern PyObject *gdbpy_gdberror_exc;
 extern void gdbpy_convert_exception (struct gdb_exception)
     CPYCHECKER_SETS_EXCEPTION;
 
-int get_addr_from_python (PyObject *obj, CORE_ADDR *addr);
+int get_addr_from_python (PyObject *obj, CORE_ADDR *addr)
+    CPYCHECKER_NEGATIVE_RESULT_SETS_EXCEPTION;
 
 PyObject *gdb_py_object_from_longest (LONGEST l);
 PyObject *gdb_py_object_from_ulongest (ULONGEST l);
-- 
1.8.1.4