Re: [PATCH v6 08/11] Support rvalue references in the gdb python module (includes doc/)

Keith Seitz
2017-03-17T17:06:46Z

Likewise, pinging this updated patch for 8.0.

Keith

On 03/10/2017 02:04 PM, Eli Zaretskii wrote:
>> From: Keith Seitz <keiths@redhat.com>
>> Date: Fri, 10 Mar 2017 12:04:43 -0800
>>
>> diff --git a/gdb/doc/python.texi b/gdb/doc/python.texi
>> index c3ea203..d463afe 100644
>> --- a/gdb/doc/python.texi
>> +++ b/gdb/doc/python.texi
>> @@ -1162,6 +1162,10 @@ A pointer-to-member.
>> @item gdb.TYPE_CODE_REF
>> A reference type.
>>
>> +@vindex TYPE_CODE_RVALUE_REF
>> +@item gdb.TYPE_CODE_RVALUE_REF
>> +An rvalue reference type.
>
> Thanks. However, I'm not sure this is enough to explain to the reader
> what this is about. At the very least, the text should mention C++.
>

I've added that this is a C++11 feature. Updated patch below.

Thanks again!

Keith

commit 731f0b2600518fce3ec1a94a9a53483bb29f3be3
Author: Artemiy Volkov <artemiyv@acm.org>
Date: Tue Mar 7 15:05:51 2017 -0800

Support rvalue references in the gdb python module (includes doc/)

This patch adds the ability to inspect rvalue reference types and values using
the gdb python module. This is achieved by creating two wrappers for
valpy_reference_value(), using the ReferenceExplorer class to handle the
objects of rvalue reference types and placing necessary checks for a
TYPE_CODE_RVALUE_REF type code next to the checks for a TYPE_CODE_REF type
code.

gdb/ChangeLog

PR gdb/14441
* doc/python.texi (Types in Python): Add TYPE_CODE_RVALUE_REF to
table of constants.
* python/lib/gdb/command/explore.py: Support exploring values
of rvalue reference types.
* python/lib/gdb/types.py: Implement get_basic_type() for
rvalue reference types.
* python/py-type.c (pyty_codes) <TYPE_CODE_RVALUE_REF>: New
constant.
* python/py-value.c (valpy_getitem): Add an rvalue reference
check.
(valpy_reference_value): Add new parameter "refcode".
(valpy_lvalue_reference_value, valpy_rvalue_reference_value):
New wrappers for valpy_reference_value().
* python/py-xmethods.c (gdbpy_get_xmethod_result_type)
(gdbpy_invoke_xmethod): Likewise.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 9670b14..20ca925 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,6 +1,25 @@
2017-MM-DD Artemiy Volkov <artemiyv@acm.org>

PR gdb/14441
+ * doc/python.texi (Types in Python): Add TYPE_CODE_RVALUE_REF to
+ table of constants.
+ * python/lib/gdb/command/explore.py: Support exploring values
+ of rvalue reference types.
+ * python/lib/gdb/types.py: Implement get_basic_type() for
+ rvalue reference types.
+ * python/py-type.c (pyty_codes) <TYPE_CODE_RVALUE_REF>: New
+ constant.
+ * python/py-value.c (valpy_getitem): Add an rvalue reference
+ check.
+ (valpy_reference_value): Add new parameter "refcode".
+ (valpy_lvalue_reference_value, valpy_rvalue_reference_value):
+ New wrappers for valpy_reference_value().
+ * python/py-xmethods.c (gdbpy_get_xmethod_result_type)
+ (gdbpy_invoke_xmethod): Likewise.
+
+2017-MM-DD Artemiy Volkov <artemiyv@acm.org>
+
+ PR gdb/14441
* dwarf2read.c (process_die, read_type_die_1): Handle the
DW_TAG_rvalue_reference_type DIE.
(read_tag_reference_type): Add new parameter "refcode".
diff --git a/gdb/doc/python.texi b/gdb/doc/python.texi
index c3ea203..15ff2a2 100644
--- a/gdb/doc/python.texi
+++ b/gdb/doc/python.texi
@@ -1162,6 +1162,10 @@ A pointer-to-member.
@item gdb.TYPE_CODE_REF
A reference type.

+@vindex TYPE_CODE_RVALUE_REF
+@item gdb.TYPE_CODE_RVALUE_REF
+A C@t{++}11 rvalue reference type.
+
@vindex TYPE_CODE_CHAR
@item gdb.TYPE_CODE_CHAR
A character type.
diff --git a/gdb/python/lib/gdb/command/explore.py b/gdb/python/lib/gdb/command/explore.py
index b2878b9..4eb2e24 100644
--- a/gdb/python/lib/gdb/command/explore.py
+++ b/gdb/python/lib/gdb/command/explore.py
@@ -132,6 +132,7 @@ class Explorer(object):
gdb.TYPE_CODE_UNION : CompoundExplorer,
gdb.TYPE_CODE_PTR : PointerExplorer,
gdb.TYPE_CODE_REF : ReferenceExplorer,
+ gdb.TYPE_CODE_RVALUE_REF : ReferenceExplorer,
gdb.TYPE_CODE_TYPEDEF : TypedefExplorer,
gdb.TYPE_CODE_ARRAY : ArrayExplorer
}
@@ -318,7 +319,6 @@ class ReferenceExplorer(object):
Explorer.explore_type(name, target_type, is_child)
return False

-
class ArrayExplorer(object):
"""Internal class used to explore arrays."""

diff --git a/gdb/python/lib/gdb/types.py b/gdb/python/lib/gdb/types.py
index 799a07d..26a5027 100644
--- a/gdb/python/lib/gdb/types.py
+++ b/gdb/python/lib/gdb/types.py
@@ -31,8 +31,10 @@ def get_basic_type(type_):
"""

while (type_.code == gdb.TYPE_CODE_REF or
+ type_.code == gdb.TYPE_CODE_RVALUE_REF or
type_.code == gdb.TYPE_CODE_TYPEDEF):
- if type_.code == gdb.TYPE_CODE_REF:
+ if (type_.code == gdb.TYPE_CODE_REF or
+ type_.code == gdb.TYPE_CODE_RVALUE_REF):
type_ = type_.target()
else:
type_ = type_.strip_typedefs()
diff --git a/gdb/python/py-type.c b/gdb/python/py-type.c
index 0249cbb..c063d2c 100644
--- a/gdb/python/py-type.c
+++ b/gdb/python/py-type.c
@@ -106,6 +106,7 @@ static struct pyty_code pyty_codes[] =
ENTRY (TYPE_CODE_METHODPTR),
ENTRY (TYPE_CODE_MEMBERPTR),
ENTRY (TYPE_CODE_REF),
+ ENTRY (TYPE_CODE_RVALUE_REF),
ENTRY (TYPE_CODE_CHAR),
ENTRY (TYPE_CODE_BOOL),
ENTRY (TYPE_CODE_COMPLEX),
diff --git a/gdb/python/py-value.c b/gdb/python/py-value.c
index c0199ea..aacf628 100644
--- a/gdb/python/py-value.c
+++ b/gdb/python/py-value.c
@@ -238,7 +238,7 @@ valpy_referenced_value (PyObject *self, PyObject *args)
/* Return a value which is a reference to the value. */

static PyObject *
-valpy_reference_value (PyObject *self, PyObject *args)
+valpy_reference_value (PyObject *self, PyObject *args, enum type_code refcode)
{
PyObject *result = NULL;

@@ -248,7 +248,7 @@ valpy_reference_value (PyObject *self, PyObject *args)
scoped_value_mark free_values;

self_val = ((value_object *) self)->value;
- result = value_to_value_object (value_ref (self_val, TYPE_CODE_REF));
+ result = value_to_value_object (value_ref (self_val, refcode));
}
CATCH (except, RETURN_MASK_ALL)
{
@@ -259,6 +259,18 @@ valpy_reference_value (PyObject *self, PyObject *args)
return result;
}

+static PyObject *
+valpy_lvalue_reference_value (PyObject *self, PyObject *args)
+{
+ return valpy_reference_value (self, args, TYPE_CODE_REF);
+}
+
+static PyObject *
+valpy_rvalue_reference_value (PyObject *self, PyObject *args)
+{
+ return valpy_reference_value (self, args, TYPE_CODE_RVALUE_REF);
+}
+
/* Return a "const" qualified version of the value. */

static PyObject *
@@ -585,8 +597,7 @@ value_has_field (struct value *v, PyObject *field)
{
val_type = value_type (v);
val_type = check_typedef (val_type);
- if (TYPE_CODE (val_type) == TYPE_CODE_REF
- || TYPE_CODE (val_type) == TYPE_CODE_PTR)
+ if (TYPE_IS_REFERENCE (val_type) || TYPE_CODE (val_type) == TYPE_CODE_PTR)
val_type = check_typedef (TYPE_TARGET_TYPE (val_type));

type_code = TYPE_CODE (val_type);
@@ -743,6 +754,9 @@ valpy_getitem (PyObject *self, PyObject *key)
else if (TYPE_CODE (val_type) == TYPE_CODE_REF)
res_val = value_cast (lookup_lvalue_reference_type (base_class_type),
tmp);
+ else if (TYPE_CODE (val_type) == TYPE_CODE_RVALUE_REF)
+ res_val = value_cast (lookup_rvalue_reference_type (base_class_type),
+ tmp);
else
res_val = value_cast (base_class_type, tmp);
}
@@ -1724,8 +1738,10 @@ reinterpret_cast operator."
{ "dereference", valpy_dereference, METH_NOARGS, "Dereferences the value." },
{ "referenced_value", valpy_referenced_value, METH_NOARGS,
"Return the value referenced by a TYPE_CODE_REF or TYPE_CODE_PTR value." },
- { "reference_value", valpy_reference_value, METH_NOARGS,
+ { "reference_value", valpy_lvalue_reference_value, METH_NOARGS,
"Return a value of type TYPE_CODE_REF referencing this value." },
+ { "rvalue_reference_value", valpy_rvalue_reference_value, METH_NOARGS,
+ "Return a value of type TYPE_CODE_RVALUE_REF referencing this value." },
{ "const_value", valpy_const_value, METH_NOARGS,
"Return a 'const' qualied version of the same value." },
{ "lazy_string", (PyCFunction) valpy_lazy_string,
diff --git a/gdb/python/py-xmethods.c b/gdb/python/py-xmethods.c
index d01488f..e061da2 100644
--- a/gdb/python/py-xmethods.c
+++ b/gdb/python/py-xmethods.c
@@ -464,9 +464,10 @@ gdbpy_get_xmethod_result_type (const struct extension_language_defn *extlang,
if (!types_equal (obj_type, this_ptr))
obj = value_cast (this_ptr, obj);
}
- else if (TYPE_CODE (obj_type) == TYPE_CODE_REF)
+ else if (TYPE_IS_REFERENCE (obj_type))
{
- struct type *this_ref = lookup_lvalue_reference_type (this_type);
+ struct type *this_ref
+ = lookup_reference_type (this_type, TYPE_CODE (obj_type));

if (!types_equal (obj_type, this_ref))
obj = value_cast (this_ref, obj);