[v2,doc] python: Provide textual representation for Inferior and Objfile
Commit Message
[New in v2: the doc part]
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
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/doc/ChangeLog:
* python.texi (Basic Python): Mention the string representation
of GDB Python objects.
---
gdb/doc/python.texi | 4 ++++
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 +-
6 files changed, 57 insertions(+), 4 deletions(-)
Comments
> From: Simon Marchi <simon.marchi@ericsson.com>
> CC: Simon Marchi <simon.marchi@ericsson.com>
> Date: Wed, 12 Sep 2018 18:50:01 -0400
>
> [New in v2: the doc part]
Thanks.
> +Some types of the @code{gdb} module come with a textual representation
> +(accessible through @code{repr()} or @code{str()}). These are offered for
> +debugging purposes only, expect them to change over time.
Please use @code{repr}, without the parens. GNU Coding Standards
frown on using the latter to indicate a function:
Please do not write '()' after a function name just to indicate it is
a function. 'foo ()' is not a function, it is a function call with no
arguments.
Otherwise OK.
>>>>> "Simon" == Simon Marchi <simon.marchi@ericsson.com> writes:
Simon> +gdb_test "python print (inferiors)" "\\(<gdb.Inferior num=1, pid=$decimal>,\\)" "verify inferiors list"
Some of the new test lines run over 80 characters.
Other than that nit the patch looks good to me.
Tom
On 2018-09-13 10:36, Tom Tromey wrote:
>>>>>> "Simon" == Simon Marchi <simon.marchi@ericsson.com> writes:
>
> Simon> +gdb_test "python print (inferiors)" "\\(<gdb.Inferior num=1,
> pid=$decimal>,\\)" "verify inferiors list"
>
> Some of the new test lines run over 80 characters.
Most of them are easy enough to make fit in 80 chars, but one is still
over, because it has a long match pattern string. My understanding was
that we were a bit more lenient on the line length for those gdb_test
lines (splitting the patterns just to comply to that rule would just
make them less readable).
> Other than that nit the patch looks good to me.
Thanks, I pushed it with those fixed as much as I can. I also addressed
Eli's comment about repr() and str().
Simon
>>>>> "Simon" == Simon Marchi <simon.marchi@polymtl.ca> writes:
Simon> On 2018-09-13 10:36, Tom Tromey wrote:
>>>>>>> "Simon" == Simon Marchi <simon.marchi@ericsson.com> writes:
>>
Simon> +gdb_test "python print (inferiors)" "\\(<gdb.Inferior num=1,
>> pid=$decimal>,\\)" "verify inferiors list"
>>
>> Some of the new test lines run over 80 characters.
Simon> Most of them are easy enough to make fit in 80 chars, but one is still
Simon> over, because it has a long match pattern string. My understanding
Simon> was that we were a bit more lenient on the line length for those
Simon> gdb_test lines (splitting the patterns just to comply to that rule
Simon> would just make them less readable).
Yeah, I agree.
Tom
@@ -207,6 +207,10 @@ methods and classes added by @value{GDBN} are placed in this module.
@value{GDBN} automatically @code{import}s the @code{gdb} module for
use in all scripts evaluated by the @code{python} command.
+Some types of the @code{gdb} module come with a textual representation
+(accessible through @code{repr()} or @code{str()}). These are offered for
+debugging purposes only, expect them to change over time.
+
@findex gdb.PYTHONDIR
@defvar gdb.PYTHONDIR
A string containing the python directory (@pxref{Python}).
@@ -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)"
@@ -279,3 +279,15 @@ 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"