[PATCH v3 08/11] [PR gdb/14441] gdb: python: support rvalue references in the gdb module

[Artemiy Volkov <artemiyv@acm.org>]

This patch adds the ability to inspect rvalue reference types and values using
the gdb python module. This is achieved by simply 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:

2016-03-04  Artemiy Volkov  <artemiyv@acm.org>

        * 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.
        * python/py-xmethods.c (gdbpy_get_xmethod_result_type)
        (gdbpy_invoke_xmethod): Likewise.
---
 gdb/python/lib/gdb/command/explore.py |  2 +-
 gdb/python/lib/gdb/types.py           |  4 +++-
 gdb/python/py-type.c                  |  1 +
 gdb/python/py-value.c                 |  3 +++
 gdb/python/py-xmethods.c              | 14 ++++++++------
 5 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/gdb/python/lib/gdb/command/explore.py b/gdb/python/lib/gdb/command/explore.py
index 6c9f17b..ed25fa6 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 c22e8a9..59b7df2 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 4ec920e..259bb70 100644
--- a/gdb/python/py-type.c
+++ b/gdb/python/py-type.c
@@ -105,6 +105,7 @@ 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 141f180..7802ae0 100644
--- a/gdb/python/py-value.c
+++ b/gdb/python/py-value.c
@@ -768,6 +768,9 @@ 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);
 	}
diff --git a/gdb/python/py-xmethods.c b/gdb/python/py-xmethods.c
index d70cdd1..859e346 100644
--- a/gdb/python/py-xmethods.c
+++ b/gdb/python/py-xmethods.c
@@ -548,10 +548,11 @@ 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 = TYPE_CODE (obj_type) == TYPE_CODE_REF
+                                ? lookup_lvalue_reference_type (this_type)
+                                : lookup_rvalue_reference_type (this_type);
       if (!types_equal (obj_type, this_ref))
 	obj = value_cast (this_ref, obj);
     }
@@ -634,10 +635,11 @@ gdbpy_invoke_xmethod (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 = TYPE_CODE (obj_type) == TYPE_CODE_REF 
+                                ? lookup_lvalue_reference_type (this_type)
+                                : lookup_rvalue_reference_type (this_type);
       if (!types_equal (obj_type, this_ref))
 	obj = value_cast (this_ref, obj);
     }
-- 
2.7.2