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Re: RFC: Python gdb.Type method returning optimized out gdb.Value
- From: Alexander Smundak <asmundak at google dot com>
- To: Doug Evans <dje at google dot com>
- Cc: gdb-patches <gdb-patches at sourceware dot org>
- Date: Tue, 7 Apr 2015 14:23:44 -0700
- Subject: Re: RFC: Python gdb.Type method returning optimized out gdb.Value
- Authentication-results: sourceware.org; auth=none
- References: <CAHQ51u5OUcPBm3D7GokB-U3hsfpzHTj+DDAWGiw35nh-AkyY1w at mail dot gmail dot com> <21796 dot 6013 dot 264282 dot 101943 at ruffy2 dot mtv dot corp dot google dot com>
Thank you for the quick review.
Edited NEWS, renamed `create_optimized_out' to `optimized_out',
elided 'unavailable' from description, added blank line.
PTAL.
gdb/doc/ChangeLog:
2015-04-07 Sasha Smundak <asmundak@google.com>
* python.texi: New method documented.
gdb/ChangeLog:
2015-04-07 Sasha Smundak <asmundak@google.com>
* NEWS: Mention gdb.Type.optimized_out method.
* python/py-type.c (typy_optimized_out): New function.
gdb/testsuite/ChangeLog:
2015-04-07 Sasha Smundak <asmundak@google.com>
* gdb.python/py-type.exp: New test.
diff --git a/gdb/NEWS b/gdb/NEWS
index 884c381..ebb573a 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -37,6 +37,8 @@
which is the name of the objfile as specified by the user,
without, for example, resolving symlinks.
** You can now write frame unwinders in Python.
+ ** gdb.Type objects have a new method "optimized_out",
+ returning optimized out gdb.Value instance of this type.
* New commands
diff --git a/gdb/doc/python.texi b/gdb/doc/python.texi
index 098d718..091521c6 100644
--- a/gdb/doc/python.texi
+++ b/gdb/doc/python.texi
@@ -1060,6 +1060,11 @@ If @var{block} is given, then @var{name} is
looked up in that scope.
Otherwise, it is searched for globally.
@end defun
+@defun Type.optimized_out ()
+Return @code{gdb.Value} instance of this type whose value is optimized
+out. This allows a frame decorator to indicate that the value of an
+argument or a local variable is not known.
+@end defun
Each type has a code, which indicates what category this type falls
into. The available type categories are represented by constants
diff --git a/gdb/python/py-type.c b/gdb/python/py-type.c
index 39376a1..0461b26 100644
--- a/gdb/python/py-type.c
+++ b/gdb/python/py-type.c
@@ -1181,6 +1181,15 @@ typy_nonzero (PyObject *self)
return 1;
}
+/* Return optimized out value of this type. */
+
+static PyObject *
+typy_optimized_out (PyObject *self, PyObject *args)
+{
+ struct type *type = ((type_object *) self)->type;
+ return value_to_value_object (allocate_optimized_out_value (type));
+}
+
/* Return a gdb.Field object for the field named by the argument. */
static PyObject *
@@ -1493,6 +1502,8 @@ They are first class values." },
{ "const", typy_const, METH_NOARGS,
"const () -> Type\n\
Return a const variant of this type." },
+ { "optimized_out", typy_optimized_out, METH_NOARGS,
+"optimized_out() -> Value\nReturn optimized out value of this type." },
{ "fields", typy_fields, METH_NOARGS,
"fields () -> list\n\
Return a list holding all the fields of this type.\n\
diff --git a/gdb/testsuite/gdb.python/py-type.exp
b/gdb/testsuite/gdb.python/py-type.exp
index c4c8d9f..2edbfe3 100644
--- a/gdb/testsuite/gdb.python/py-type.exp
+++ b/gdb/testsuite/gdb.python/py-type.exp
@@ -253,6 +253,9 @@ gdb_test "python print
gdb.lookup_type('char').array(1, 0)" \
gdb_test "python print gdb.lookup_type('char').array(1, -1)" \
"Array length must not be negative.*"
+gdb_test "python print gdb.lookup_type('int').optimized_out()" \
+ "<optimized out>"
+
with_test_prefix "lang_c" {
runto_bp "break to inspect struct and array."
test_fields "c"
On Tue, Apr 7, 2015 at 10:44 AM, Doug Evans <dje@google.com> wrote:
> Alexander Smundak writes:
> > Provide the ability for a a Python frame decorator to indicate that
> > a value is not available.
> >
> > doc/ChangeLog:
> >
> > 2015-04-03 Sasha Smundak <asmundak@google.com>
> >
> > * python.texi:New method documented.
> >
> > gdb/ChangeLog:
> >
> > 2015-04-03 Sasha Smundak <asmundak@google.com>
> >
> > * python/py-type.c (typy_create_optimized_out): New function.
> >
> > testsuite/ChangeLog:
> >
> > 2015-04-03 Sasha Smundak <asmundak@google.com>
> >
> > * gdb.python/py-type.exp: New test.
>
> Hi.
> A few of nits.
>
> The terms "unavailable" and "optimized out" have different meanings
> in gdb. See their definitions at the top of value.h.
> Also see the comments for struct value.{unavailable,optimized_out}
> in value.c. I don't know if python frame decorators would want to specify
> a value as being unavailable (in gdb parlance), but don't use "unavailable"
> in the documentation of "optimized out".
>
> The "create_" in "create_optimized_out" is incongruous with the
> rest of gdb.Type methods. E.g., we have "array" not "create_array",
> "vector" not "create_vector", "const" not "create_const", and so on.
> Does "optimized_out" read well to you?
>
> A NEWS entry is needed.
>
> >
> > diff --git a/gdb/doc/python.texi b/gdb/doc/python.texi
> > index 098d718..7c2d0bc 100644
> > --- a/gdb/doc/python.texi
> > +++ b/gdb/doc/python.texi
> > @@ -1060,6 +1060,11 @@ If @var{block} is given, then @var{name} is
> > looked up in that scope.
> > Otherwise, it is searched for globally.
> > @end defun
> >
> > +@defun Type.create_optimized_out ()
> > +Return @code{gdb.Value} instance of this type whose value is optimized
> > +out. Allows a frame decorator to indicate that an argument or local
> > +variable value is unavailable.
> > +@end defun
> >
> > Each type has a code, which indicates what category this type falls
> > into. The available type categories are represented by constants
> > diff --git a/gdb/python/py-type.c b/gdb/python/py-type.c
> > index 39376a1..186cc19 100644
> > --- a/gdb/python/py-type.c
> > +++ b/gdb/python/py-type.c
> > @@ -1181,6 +1181,14 @@ typy_nonzero (PyObject *self)
> > return 1;
> > }
> >
> > +/* Return optimized out value of this type. */
>
> blank line
>
> > +static PyObject *
> > +typy_create_optimized_out (PyObject *self, PyObject *args)
> > +{
> > + struct type *type = ((type_object *) self)->type;
> > + return value_to_value_object (allocate_optimized_out_value (type));
> > +}
> > +
> > /* Return a gdb.Field object for the field named by the argument. */
> >
> > static PyObject *
> > @@ -1493,6 +1501,8 @@ They are first class values." },
> > { "const", typy_const, METH_NOARGS,
> > "const () -> Type\n\
> > Return a const variant of this type." },
> > + { "create_optimized_out", typy_create_optimized_out, METH_NOARGS,
> > +"create_optimized_out() -> Value\nReturn optimized out value of this type." },
> > { "fields", typy_fields, METH_NOARGS,
> > "fields () -> list\n\
> > Return a list holding all the fields of this type.\n\
> > diff --git a/gdb/testsuite/gdb.python/py-type.exp
> > b/gdb/testsuite/gdb.python/py-type.exp
> > index c4c8d9f..c73f831 100644
> > --- a/gdb/testsuite/gdb.python/py-type.exp
> > +++ b/gdb/testsuite/gdb.python/py-type.exp
> > @@ -253,6 +253,9 @@ gdb_test "python print
> > gdb.lookup_type('char').array(1, 0)" \
> > gdb_test "python print gdb.lookup_type('char').array(1, -1)" \
> > "Array length must not be negative.*"
> >
> > +gdb_test "python print gdb.lookup_type('int').create_optimized_out()" \
> > + "<optimized out>"
> > +
> > with_test_prefix "lang_c" {
> > runto_bp "break to inspect struct and array."
> > test_fields "c"
>
> --
> /dje