python: Provide textual representation for Inferior and Objfile
Commit Message
Printing a GDB Python object is notoriously not helpful:
>>> print(gdb.selected_inferior())
<gdb.Inferior object at 0x7fea59aed198>
>>> print(gdb.objfiles())
[<gdb.Objfile object at 0x7fea59b57c90>]
This makes printing debug traces more difficult than it should be. This
patch provides some repr() implementation for these two types (more to
come if people agree with the idea, but I want to test the water first).
Here's the same example as above, but with this patch:
>>> print(gdb.selected_inferior())
<gdb.Inferior num=1>
>>> print(gdb.objfiles())
[<gdb.Objfile filename=/home/emaisin/build/binutils-gdb-gcc-git/gdb/test>]
I implemented repr rather than str, because when printing a list (or
another container I suppose), Python calls the repr method of the
elements. This is useful when printing a list of inferiors or objfiles.
The print(gdb.objfiles()) above would not have worked if I had
implemented str.
I found this post useful to understand the difference between repr and
str:
https://stackoverflow.com/questions/1436703/difference-between-str-and-repr
In your opinion, does this require an announcement in NEWS and an entry
in the manual? I don't think the output of repr() should be considered
stable, as we could change it over time to make it more useful. Maybe
that should be documented?
gdb/ChangeLog:
* python/py-inferior.c (infpy_repr): New.
(inferior_object_type): Register infpy_repr.
* python/py-objfile.c (objfpy_repr): New.
(objfile_object_type): Register objfpy_repr.
gdb/testsuite/ChangeLog:
* gdb.python/py-inferior.exp: Test repr() of gdb.Inferior.
* gdb.python/py-objfile.exp: Test repr() of gdb.Objfile.
* gdb.python/py-symtab.exp: Update test printing an objfile.
---
gdb/python/py-inferior.c | 17 ++++++++++++++++-
gdb/python/py-objfile.c | 17 ++++++++++++++++-
gdb/testsuite/gdb.python/py-inferior.exp | 14 +++++++++++++-
gdb/testsuite/gdb.python/py-objfile.exp | 7 +++++++
gdb/testsuite/gdb.python/py-symtab.exp | 2 +-
5 files changed, 53 insertions(+), 4 deletions(-)
Comments
>>>>> "Simon" == Simon Marchi <simon.marchi@ericsson.com> writes:
Simon> This makes printing debug traces more difficult than it should be. This
Simon> patch provides some repr() implementation for these two types (more to
Simon> come if people agree with the idea, but I want to test the water first).
I think it is a good idea.
Simon> In your opinion, does this require an announcement in NEWS and an entry
Simon> in the manual? I don't think the output of repr() should be considered
Simon> stable, as we could change it over time to make it more useful. Maybe
Simon> that should be documented?
That seems like a reasonable rule to me. One idea would be to make this
a general rule for the gdb Python layer and document it in the "Basic
Python" node.
I could go either way about a NEWS entry. It seems more like a
debugging convenience feature maybe? Dunno.
The patch looks good.
Tom
On 2018-09-12 18:07, Tom Tromey wrote:
>>>>>> "Simon" == Simon Marchi <simon.marchi@ericsson.com> writes:
>
> Simon> This makes printing debug traces more difficult than it should
> be. This
> Simon> patch provides some repr() implementation for these two types
> (more to
> Simon> come if people agree with the idea, but I want to test the water
> first).
>
> I think it is a good idea.
>
> Simon> In your opinion, does this require an announcement in NEWS and
> an entry
> Simon> in the manual? I don't think the output of repr() should be
> considered
> Simon> stable, as we could change it over time to make it more useful.
> Maybe
> Simon> that should be documented?
>
> That seems like a reasonable rule to me. One idea would be to make
> this
> a general rule for the gdb Python layer and document it in the "Basic
> Python" node.
Good idea, a blanket warning (for string repr of all object types) in
there should be enough. I'll do it that.
> I could go either way about a NEWS entry. It seems more like a
> debugging convenience feature maybe? Dunno.
That's what I think too.
Thanks,
Simon
@@ -860,6 +860,21 @@ infpy_thread_from_thread_handle (PyObject *self, PyObject *args, PyObject *kw)
return result;
}
+/* Implement repr() for gdb.Inferior. */
+
+static PyObject *
+infpy_repr (PyObject *obj)
+{
+ inferior_object *self = (inferior_object *) obj;
+ inferior *inf = self->inferior;
+
+ if (inf == nullptr)
+ return PyString_FromString ("<gdb.Inferior (invalid)>");
+
+ return PyString_FromFormat ("<gdb.Inferior num=%d, pid=%d>",
+ inf->num, inf->pid);
+}
+
static void
infpy_dealloc (PyObject *obj)
@@ -991,7 +1006,7 @@ PyTypeObject inferior_object_type =
0, /* tp_getattr */
0, /* tp_setattr */
0, /* tp_compare */
- 0, /* tp_repr */
+ infpy_repr, /* tp_repr */
0, /* tp_as_number */
0, /* tp_as_sequence */
0, /* tp_as_mapping */
@@ -456,6 +456,21 @@ objfpy_add_separate_debug_file (PyObject *self, PyObject *args, PyObject *kw)
Py_RETURN_NONE;
}
+/* Implement repr() for gdb.Objfile. */
+
+static PyObject *
+objfpy_repr (PyObject *self_)
+{
+ objfile_object *self = (objfile_object *) self_;
+ objfile *obj = self->objfile;
+
+ if (obj == nullptr)
+ return PyString_FromString ("<gdb.Objfile (invalid)>");
+
+ return PyString_FromFormat ("<gdb.Objfile filename=%s>",
+ objfile_filename (obj));
+}
+
/* Subroutine of gdbpy_lookup_objfile_by_build_id to simplify it.
Return non-zero if STRING is a potentially valid build id. */
@@ -709,7 +724,7 @@ PyTypeObject objfile_object_type =
0, /*tp_getattr*/
0, /*tp_setattr*/
0, /*tp_compare*/
- 0, /*tp_repr*/
+ objfpy_repr, /*tp_repr*/
0, /*tp_as_number*/
0, /*tp_as_sequence*/
0, /*tp_as_mapping*/
@@ -45,7 +45,7 @@ if ![runto_main] then {
# Test basic gdb.Inferior attributes and methods.
gdb_py_test_silent_cmd "python inferiors = gdb.inferiors ()" "get inferiors list" 1
-gdb_test "python print (inferiors)" "\\(<gdb.Inferior object at 0x\[\[:xdigit:\]\]+>,\\)" "verify inferiors list"
+gdb_test "python print (inferiors)" "\\(<gdb.Inferior num=1, pid=$decimal>,\\)" "verify inferiors list"
gdb_py_test_silent_cmd "python i0 = inferiors\[0\]" "get first inferior" 0
gdb_test "python print ('result = %s' % (i0 == inferiors\[0\]))" " = True" "test equality comparison (true)"
@@ -266,3 +266,15 @@ with_test_prefix "selected_inferior" {
gdb_test "inferior 1" ".*" "switch back to first inferior"
gdb_test_no_output "remove-inferiors 3" "remove second inferior"
}
+
+# Test repr()/str()
+with_test_prefix "__repr__" {
+ gdb_test "add-inferior" "Added inferior 4" "add inferior 4"
+ gdb_py_test_silent_cmd "python infs = gdb.inferiors()" "get inferior list" 1
+ gdb_test "python print (infs\[0\])" "<gdb.Inferior num=1, pid=$decimal>"
+ gdb_test "python print (infs)" "\\\(<gdb.Inferior num=1, pid=$decimal>, <gdb.Inferior num=4, pid=$decimal>\\\)" \
+ "print all inferiors 1"
+ gdb_test_no_output "remove-inferiors 4"
+ gdb_test "python print (infs)" "\\\(<gdb.Inferior num=1, pid=$decimal>, <gdb.Inferior \\\(invalid\\\)>\\\)" \
+ "print all inferiors 2"
+}
@@ -45,6 +45,8 @@ gdb_test "python print (objfile.filename)" "${testfile}" \
gdb_test "python print (objfile.username)" "${testfile}" \
"Get objfile user name"
+gdb_test "python print (objfile)" "<gdb.Objfile filename=[string_to_regexp ${binfile}]>"
+
gdb_test_no_output "python dir(objfile)"
gdb_test "python print (gdb.lookup_objfile (\"${testfile}\").filename)" \
@@ -149,3 +151,8 @@ if [remote_file host exists "${symlink_binary}"] {
gdb_test "python print (gdb.lookup_objfile (\"${symlink_binary}\").filename)" \
"${testfile}" "gdb.lookup_objfile of symlinked binary"
}
+
+# Test printing an Objfile object that is no longer valid.
+gdb_py_test_silent_cmd "python objfile = gdb.objfiles()\[0\]" "get first objfile" 1
+gdb_file_cmd ${binfile}
+gdb_test "python print(objfile)" "<gdb.Objfile \\\(invalid\\\)>"
\ No newline at end of file
@@ -66,7 +66,7 @@ gdb_test "python print (sal.is_valid())" "True" "test sal.is_valid"
# Test symbol table.
gdb_test "python print (symtab.filename)" ".*${py_symbol_c}" "test symtab.filename"
-gdb_test "python print (symtab.objfile)" "<gdb.Objfile object at ${hex}>" "test symtab.objfile"
+gdb_test "python print (symtab.objfile)" "<gdb.Objfile filename=${binfile}>" "test symtab.objfile"
gdb_test "python print (symtab.fullname())" ".*${full_py_symbol_c}" "test symtab.fullname"
gdb_test "python print (symtab.is_valid())" "True" "test symtab.is_valid()"
gdb_test "python print (\"qq\" in global_symbols)" "True" "test qq in global symbols"