python: Add Progspace.objfiles method

This patch adds an objfiles method to the Progspace object, which
returns a sequence of the objfiles associated to that program space.  I
chose a method rather than a property for symmetry with gdb.objfiles().

gdb/ChangeLog:

	* python/py-progspace.c (PSPY_REQUIRE_VALID): New macro.
	(pspy_get_objfiles): New function.
	(progspace_object_methods): New.
	(pspace_object_type): Add tp_methods callback.
	* python/python-internal.h (build_objfiles_list): New
	declaration.
	* python/python.c (build_objfiles_list): New function.
	(gdbpy_objfiles): Implement using build_objfiles_list.
	* NEWS: Mention the Progspace.objfiles method.

gdb/doc/ChangeLog:

	* python.texi (Program Spaces In Python): Document the
	Progspace.objfiles method.
	(Objfiles In Python): Mention that gdb.objfiles() is identical
	to gdb.selected_inferior().progspace.objfiles().

gdb/testsuite/ChangeLog:

	* gdb.python/py-progspace.exp: Test the Progspace.objfiles
	method.

3 files changed, 51 insertions, 13 deletions

diff --git a/gdb/python/py-progspace.c b/gdb/python/py-progspace.c
index 3eaa466..e01338f 100644
--- a/gdb/python/py-progspace.c
+++ b/gdb/python/py-progspace.c
@@ -58,7 +58,16 @@ extern PyTypeObject pspace_object_type
 
 static const struct program_space_data *pspy_pspace_data_key;
 
-
+/* Require that PSPACE_OBJ be a valid program space ID.  */
+#define PSPY_REQUIRE_VALID(pspace_obj)				\
+  do {								\
+    if (pspace_obj->pspace == nullptr)				\
+      {								\
+	PyErr_SetString (PyExc_RuntimeError,			\
+			 _("Program space no longer exists."));	\
+	return NULL;						\
+      }								\
+  } while (0)
 
 /* An Objfile method which returns the objfile's file name, or None.  */
 
@@ -314,7 +323,17 @@ pspy_set_type_printers (PyObject *o, PyObject *value, void *ignore)
   return 0;
 }
 
-
+/* Implement the objfiles method.  */
+
+static PyObject *
+pspy_get_objfiles (PyObject *self_, PyObject *args)
+{
+  pspace_object *self = (pspace_object *) self_;
+
+  PSPY_REQUIRE_VALID (self);
+
+  return build_objfiles_list (self->pspace).release ();
+}
 
 /* Clear the PSPACE pointer in a Pspace object and remove the reference.  */
 
@@ -397,6 +416,13 @@ static gdb_PyGetSetDef pspace_getset[] =
   { NULL }
 };
 
+static PyMethodDef progspace_object_methods[] =
+{
+  { "objfiles", pspy_get_objfiles, METH_NOARGS,
+    "Return a sequence of objfiles associated to this program space." },
+  { NULL }
+};
+
 PyTypeObject pspace_object_type =
 {
   PyVarObject_HEAD_INIT (NULL, 0)
@@ -426,7 +452,7 @@ PyTypeObject pspace_object_type =
   0,				  /* tp_weaklistoffset */
   0,				  /* tp_iter */
   0,				  /* tp_iternext */
-  0,				  /* tp_methods */
+  progspace_object_methods,	  /* tp_methods */
   0,				  /* tp_members */
   pspace_getset,		  /* tp_getset */
   0,				  /* tp_base */
diff --git a/gdb/python/python-internal.h b/gdb/python/python-internal.h
index 3874fdc..785ad17 100644
--- a/gdb/python/python-internal.h
+++ b/gdb/python/python-internal.h
@@ -549,6 +549,10 @@ struct symtab_and_line *sal_object_to_symtab_and_line (PyObject *obj);
 struct frame_info *frame_object_to_frame_info (PyObject *frame_obj);
 struct gdbarch *arch_object_to_gdbarch (PyObject *obj);
 
+/* Return a Python list containing an Objfile object for each objfile in
+   PSPACE.  */
+gdbpy_ref<> build_objfiles_list (program_space *pspace);
+
 void gdbpy_initialize_gdb_readline (void);
 int gdbpy_initialize_auto_load (void)
   CPYCHECKER_NEGATIVE_RESULT_SETS_EXCEPTION;
diff --git a/gdb/python/python.c b/gdb/python/python.c
index 6f798a0..371f4a5 100644
--- a/gdb/python/python.c
+++ b/gdb/python/python.c
@@ -1437,10 +1437,10 @@ gdbpy_get_current_objfile (PyObject *unused1, PyObject *unused2)
   return result;
 }
 
-/* Return a sequence holding all the Objfiles.  */
+/* See python-internal.h.  */
 
-static PyObject *
-gdbpy_objfiles (PyObject *unused1, PyObject *unused2)
+gdbpy_ref<>
+build_objfiles_list (program_space *pspace)
 {
   struct objfile *objf;
 
@@ -1448,15 +1448,23 @@ gdbpy_objfiles (PyObject *unused1, PyObject *unused2)
   if (list == NULL)
     return NULL;
 
-  ALL_OBJFILES (objf)
-  {
-    PyObject *item = objfile_to_objfile_object (objf);
+  ALL_PSPACE_OBJFILES (pspace, objf)
+    {
+      PyObject *item = objfile_to_objfile_object (objf);
 
-    if (!item || PyList_Append (list.get (), item) == -1)
-      return NULL;
-  }
+      if (item == nullptr || PyList_Append (list.get (), item) == -1)
+	return NULL;
+    }
 
-  return list.release ();
+  return list;
+}
+
+/* Return a sequence holding all the Objfiles.  */
+
+static PyObject *
+gdbpy_objfiles (PyObject *unused1, PyObject *unused2)
+{
+  return build_objfiles_list (current_program_space).release ();
 }
 
 /* Compute the list of active python type printers and store them in