diff mbox

[doc,RFA] Add ability to set random attributes in python objfiles,progspaces

Message ID 21569.31750.685018.824870@ruffy.mtv.corp.google.com
State New
Headers show

Commit Message

Doug Evans Oct. 17, 2014, 8:28 p.m. UTC
Phil Muldoon writes:
 > On 10/10/14 18:35, Doug Evans wrote:
 > > Phil Muldoon writes:
 > >  > Maybe add a small example here as you did with gdb.Objfile?  Or maybe
 > >  > an xref.  One of my goals in the next year is to add (and backfill in
 > >  > existing documentation) more example led documentation for Python.
 > >  > Sometimes an example speaks (ten) thousand words!
 > >
 > > I couldn't think of a simple one.
 > 
 > Maybe document (as in describe) a more complex one? 

How about this?

2014-10-17  Doug Evans  <dje@google.com>

	* NEWS: Mention ability add attributes to gdb.Objfile and
	gdb.Progspace objects.
	* python/py-objfile.c (objfile_object): New member dict.
	(objfpy_dealloc): Py_XDECREF dict.
	(objfpy_initialize): Initialize dict.
	(objfile_getset): Add __dict__.
	(objfile_object_type): Set tp_dictoffset member.
	* python/py-progspace.c (progspace_object): New member dict.
	(pspy_dealloc): Py_XDECREF dict.
	(pspy_initialize): Initialize dict.
	(pspace_getset): Add __dict__.
	(pspace_object_type): Set tp_dictoffset member.

	doc/
	* python.texi (Progspaces In Python): Document ability to add
	random attributes to gdb.Progspace objects.
	(Objfiles In Python): Document ability to add random attributes to
	gdb.objfile objects.

	testsuite/
	* gdb.python/py-objfile.exp: Add tests for setting random attributes
	in objfiles.
	* gdb.python/py-progspace.exp: Add tests for setting random attributes
	in progspaces.

Comments

Eli Zaretskii Oct. 18, 2014, 5:39 a.m. UTC | #1
> From: Doug Evans <dje@google.com>
> Date: Fri, 17 Oct 2014 13:28:54 -0700
> Cc: gdb-patches@sourceware.org    
> 
> Phil Muldoon writes:
>  > On 10/10/14 18:35, Doug Evans wrote:
>  > > Phil Muldoon writes:
>  > >  > Maybe add a small example here as you did with gdb.Objfile?  Or maybe
>  > >  > an xref.  One of my goals in the next year is to add (and backfill in
>  > >  > existing documentation) more example led documentation for Python.
>  > >  > Sometimes an example speaks (ten) thousand words!
>  > >
>  > > I couldn't think of a simple one.
>  > 
>  > Maybe document (as in describe) a more complex one? 
> 
> How about this?

Fine with me, thanks.
Doug Evans Oct. 21, 2014, 4:53 p.m. UTC | #2
On Fri, Oct 17, 2014 at 10:39 PM, Eli Zaretskii <eliz@gnu.org> wrote:
>> From: Doug Evans <dje@google.com>
>> Date: Fri, 17 Oct 2014 13:28:54 -0700
>> Cc: gdb-patches@sourceware.org
>>
>> Phil Muldoon writes:
>>  > On 10/10/14 18:35, Doug Evans wrote:
>>  > > Phil Muldoon writes:
>>  > >  > Maybe add a small example here as you did with gdb.Objfile?  Or maybe
>>  > >  > an xref.  One of my goals in the next year is to add (and backfill in
>>  > >  > existing documentation) more example led documentation for Python.
>>  > >  > Sometimes an example speaks (ten) thousand words!
>>  > >
>>  > > I couldn't think of a simple one.
>>  >
>>  > Maybe document (as in describe) a more complex one?
>>
>> How about this?
>
> Fine with me, thanks.

Thanks.  Phil?
Phil Muldoon Oct. 21, 2014, 6:23 p.m. UTC | #3
On 21/10/14 17:53, Doug Evans wrote:
> On Fri, Oct 17, 2014 at 10:39 PM, Eli Zaretskii <eliz@gnu.org> wrote:
>>> From: Doug Evans <dje@google.com>
>>> Date: Fri, 17 Oct 2014 13:28:54 -0700
>>> Cc: gdb-patches@sourceware.org
>>>
>>> Phil Muldoon writes:
>>>  > On 10/10/14 18:35, Doug Evans wrote:
>>>  > > Phil Muldoon writes:
>>>  > >  > Maybe add a small example here as you did with gdb.Objfile?  Or maybe
>>>  > >  > an xref.  One of my goals in the next year is to add (and backfill in
>>>  > >  > existing documentation) more example led documentation for Python.
>>>  > >  > Sometimes an example speaks (ten) thousand words!
>>>  > >
>>>  > > I couldn't think of a simple one.
>>>  >
>>>  > Maybe document (as in describe) a more complex one?
>>>
>>> How about this?
>> Fine with me, thanks.
> Thanks.  Phil?

Apologies for the delay. Looks super.

Thanks Doug.

Cheers,

Phil
Doug Evans Oct. 31, 2014, 12:07 a.m. UTC | #4
On Tue, Oct 21, 2014 at 11:23 AM, Phil Muldoon <pmuldoon@redhat.com> wrote:
> On 21/10/14 17:53, Doug Evans wrote:
>> On Fri, Oct 17, 2014 at 10:39 PM, Eli Zaretskii <eliz@gnu.org> wrote:
>>>> From: Doug Evans <dje@google.com>
>>>> Date: Fri, 17 Oct 2014 13:28:54 -0700
>>>> Cc: gdb-patches@sourceware.org
>>>>
>>>> Phil Muldoon writes:
>>>>  > On 10/10/14 18:35, Doug Evans wrote:
>>>>  > > Phil Muldoon writes:
>>>>  > >  > Maybe add a small example here as you did with gdb.Objfile?  Or maybe
>>>>  > >  > an xref.  One of my goals in the next year is to add (and backfill in
>>>>  > >  > existing documentation) more example led documentation for Python.
>>>>  > >  > Sometimes an example speaks (ten) thousand words!
>>>>  > >
>>>>  > > I couldn't think of a simple one.
>>>>  >
>>>>  > Maybe document (as in describe) a more complex one?
>>>>
>>>> How about this?
>>> Fine with me, thanks.
>> Thanks.  Phil?
>
> Apologies for the delay. Looks super.

No worries on the delay. :-)

Committed, thanks.
diff mbox

Patch

diff --git a/gdb/NEWS b/gdb/NEWS
index 606fd16..33b2259 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -13,6 +13,7 @@ 
      which is the gdb.Progspace object of the containing program space.
   ** A new event "gdb.clear_objfiles" has been added, triggered when
      selecting a new file to debug.
+  ** You can now add attributes to gdb.Objfile and gdb.Progspace objects.
 
 * New Python-based convenience functions:
 
diff --git a/gdb/doc/python.texi b/gdb/doc/python.texi
index 43663d8..caaa259 100644
--- a/gdb/doc/python.texi
+++ b/gdb/doc/python.texi
@@ -3366,6 +3366,50 @@  The @code{frame_filters} attribute is a dictionary of frame filter
 objects.  @xref{Frame Filter API}, for more information.
 @end defvar
 
+One may add arbitrary attributes to @code{gdb.Progspace} objects
+in the usual Python way.
+This is useful if, for example, one needs to do some extra record keeping
+associated with the program space.
+
+In this contrived example, we want to perform some processing when
+an objfile with a certain symbol is loaded, but we only want to do
+this once because it is expensive.  To achieve this we record the results
+with the program space because we can't predict when the desired objfile
+will be loaded.
+
+@smallexample
+(gdb) python
+def clear_objfiles_handler(event):
+    event.progspace.expensive_computation = None
+def expensive(symbol):
+    """A mock routine to perform an "expensive" computation on symbol."""
+    print "Computing the answer to the ultimate question ..."
+    return 42
+def new_objfile_handler(event):
+    objfile = event.new_objfile
+    progspace = objfile.progspace
+    if not hasattr(progspace, 'expensive_computation') or \
+            progspace.expensive_computation is None:
+        # We use 'main' for the symbol to keep the example simple.
+        # Note: There's no current way to constrain the lookup
+        # to one objfile.
+        symbol = gdb.lookup_global_symbol('main')
+        if symbol is not None:
+            progspace.expensive_computation = expensive(symbol)
+gdb.events.clear_objfiles.connect(clear_objfiles_handler)
+gdb.events.new_objfile.connect(new_objfile_handler)
+end
+(gdb) file /tmp/hello
+Reading symbols from /tmp/hello...done.
+Computing the answer to the ultimate question ...
+(gdb) python print gdb.current_progspace().expensive_computation
+42
+(gdb) run
+Starting program: /tmp/hello
+Hello.
+[Inferior 1 (process 4242) exited normally]
+@end smallexample
+
 @node Objfiles In Python
 @subsubsection Objfiles In Python
 
@@ -3426,6 +3470,28 @@  The @code{frame_filters} attribute is a dictionary of frame filter
 objects.  @xref{Frame Filter API}, for more information.
 @end defvar
 
+One may add arbitrary attributes to @code{gdb.Objfile} objects
+in the usual Python way.
+This is useful if, for example, one needs to do some extra record keeping
+associated with the objfile.
+
+In this contrived example we record the time when @value{GDBN}
+loaded the objfile.
+
+@smallexample
+(gdb) python
+import datetime
+def new_objfile_handler(event):
+    # Set the time_loaded attribute of the new objfile.
+    event.new_objfile.time_loaded = datetime.datetime.today()
+gdb.events.new_objfile.connect(new_objfile_handler)
+end
+(gdb) file ./hello
+Reading symbols from ./hello...done.
+(gdb) python print gdb.objfiles()[0].time_loaded
+2014-10-09 11:41:36.770345
+@end smallexample
+
 A @code{gdb.Objfile} object has the following methods:
 
 @defun Objfile.is_valid ()
diff --git a/gdb/python/py-objfile.c b/gdb/python/py-objfile.c
index e868223..c99de87 100644
--- a/gdb/python/py-objfile.c
+++ b/gdb/python/py-objfile.c
@@ -30,6 +30,10 @@  typedef struct
   /* The corresponding objfile.  */
   struct objfile *objfile;
 
+  /* Dictionary holding user-added attributes.
+     This is the __dict__ attribute of the object.  */
+  PyObject *dict;
+
   /* The pretty-printer list of functions.  */
   PyObject *printers;
 
@@ -85,6 +89,7 @@  objfpy_dealloc (PyObject *o)
 {
   objfile_object *self = (objfile_object *) o;
 
+  Py_XDECREF (self->dict);
   Py_XDECREF (self->printers);
   Py_XDECREF (self->frame_filters);
   Py_XDECREF (self->type_printers);
@@ -99,6 +104,7 @@  static int
 objfpy_initialize (objfile_object *self)
 {
   self->objfile = NULL;
+  self->dict = NULL;
 
   self->printers = PyList_New (0);
   if (self->printers == NULL)
@@ -354,6 +360,8 @@  Return true if this object file is valid, false if not." },
 
 static PyGetSetDef objfile_getset[] =
 {
+  { "__dict__", gdb_py_generic_dict, NULL,
+    "The __dict__ for this objfile.", &objfile_object_type },
   { "filename", objfpy_get_filename, NULL,
     "The objfile's filename, or None.", NULL },
   { "progspace", objfpy_get_progspace, NULL,
@@ -405,7 +413,7 @@  static PyTypeObject objfile_object_type =
   0,				  /* tp_dict */
   0,				  /* tp_descr_get */
   0,				  /* tp_descr_set */
-  0,				  /* tp_dictoffset */
+  offsetof (objfile_object, dict), /* tp_dictoffset */
   0,				  /* tp_init */
   0,				  /* tp_alloc */
   objfpy_new,			  /* tp_new */
diff --git a/gdb/python/py-progspace.c b/gdb/python/py-progspace.c
index 4280032..96339b1 100644
--- a/gdb/python/py-progspace.c
+++ b/gdb/python/py-progspace.c
@@ -32,6 +32,10 @@  typedef struct
   /* The corresponding pspace.  */
   struct program_space *pspace;
 
+  /* Dictionary holding user-added attributes.
+     This is the __dict__ attribute of the object.  */
+  PyObject *dict;
+
   /* The pretty-printer list of functions.  */
   PyObject *printers;
 
@@ -75,6 +79,7 @@  pspy_dealloc (PyObject *self)
 {
   pspace_object *ps_self = (pspace_object *) self;
 
+  Py_XDECREF (ps_self->dict);
   Py_XDECREF (ps_self->printers);
   Py_XDECREF (ps_self->frame_filters);
   Py_XDECREF (ps_self->type_printers);
@@ -89,6 +94,7 @@  static int
 pspy_initialize (pspace_object *self)
 {
   self->pspace = NULL;
+  self->dict = NULL;
 
   self->printers = PyList_New (0);
   if (self->printers == NULL)
@@ -331,6 +337,8 @@  gdbpy_initialize_pspace (void)
 
 static PyGetSetDef pspace_getset[] =
 {
+  { "__dict__", gdb_py_generic_dict, NULL,
+    "The __dict__ for this progspace.", &pspace_object_type },
   { "filename", pspy_get_filename, NULL,
     "The progspace's main filename, or None.", NULL },
   { "pretty_printers", pspy_get_printers, pspy_set_printers,
@@ -380,7 +388,7 @@  static PyTypeObject pspace_object_type =
   0,				  /* tp_dict */
   0,				  /* tp_descr_get */
   0,				  /* tp_descr_set */
-  0,				  /* tp_dictoffset */
+  offsetof (pspace_object, dict), /* tp_dictoffset */
   0,				  /* tp_init */
   0,				  /* tp_alloc */
   pspy_new,			  /* tp_new */
diff --git a/gdb/testsuite/gdb.python/py-objfile.exp b/gdb/testsuite/gdb.python/py-objfile.exp
index 8796170..7bf41ed 100644
--- a/gdb/testsuite/gdb.python/py-objfile.exp
+++ b/gdb/testsuite/gdb.python/py-objfile.exp
@@ -46,3 +46,8 @@  gdb_test "python print (objfile.is_valid())" "True" \
 gdb_unload
 gdb_test "python print (objfile.is_valid())" "False" \
   "Get objfile validity after unload"
+
+gdb_py_test_silent_cmd "python objfile.random_attribute = 42" \
+    "Set random attribute in objfile" 1
+gdb_test "python print (objfile.random_attribute)" "42" \
+    "Verify set of random attribute in objfile"
diff --git a/gdb/testsuite/gdb.python/py-progspace.exp b/gdb/testsuite/gdb.python/py-progspace.exp
index 2fcfdb9..a47fae6 100644
--- a/gdb/testsuite/gdb.python/py-progspace.exp
+++ b/gdb/testsuite/gdb.python/py-progspace.exp
@@ -16,6 +16,8 @@ 
 # This file is part of the GDB testsuite.  It tests the program space
 # support in Python.
 
+load_lib gdb-python.exp
+
 standard_testfile
 
 if {[build_executable $testfile.exp $testfile $srcfile debug] == -1} {
@@ -37,5 +39,13 @@  gdb_test "python print (gdb.progspaces())" "\\\[<gdb.Progspace object at $hex>\\
 
 gdb_load ${binfile}
 
-gdb_test "python print (gdb.current_progspace().filename)" "py-progspace" \
+gdb_py_test_silent_cmd "python progspace = gdb.current_progspace()" \
+    "Get current progspace" 1
+
+gdb_test "python print (progspace.filename)" "py-progspace" \
   "current progspace filename (py-progspace)"
+
+gdb_py_test_silent_cmd "python progspace.random_attribute = 42" \
+    "Set random attribute in progspace" 1
+gdb_test "python print (progspace.random_attribute)" "42" \
+    "Verify set of random attribute in progspace"