[Bug python/14077] New: Dynamic type of references cannot be accessed

[Bug python/14077] New: Dynamic type of references cannot be accessed

[andre.poenitz at nokia dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=14077

             Bug #: 14077
           Summary: Dynamic type of references cannot be accessed
           Product: gdb
           Version: HEAD
            Status: NEW
          Severity: enhancement
          Priority: P2
         Component: python
        AssignedTo: unassigned@sourceware.org
        ReportedBy: andre.poenitz@nokia.com
    Classification: Unclassified


echo "
struct A { virtual ~A() {} int a; };
struct B : A {};

int main()
{
    B b;
    A *b1 = &b;
    A &b2 = b;
    return b1->a + b2.a;
}
" | g++ -g -xc++ -

~/debugger/gdb-git-i586/gdb/gdb \
    -ex "set confirm off" \
    -ex "file ./a.out" \
    -ex "b 10" \
    -ex run \
    -ex "python print 'Pointer   static  type : %s' %
gdb.parse_and_eval('b1').type" \
    -ex "python print 'Pointer   dynamic type : %s' %
gdb.parse_and_eval('b1').dynamic_type" \
    -ex "python print 'Reference static  type : %s' %
gdb.parse_and_eval('b2').type" \
    -ex "python print 'Reference dynamic type : %s' %
gdb.parse_and_eval('b2').dynamic_type" 



yields:

    Pointer   static  type : A *
    Pointer   dynamic type : B *
    Reference static  type : A &
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
    gdb.error: Attempt to take contents of a non-pointer value.
    Error while executing Python code.


It would be convenient to see   

    Reference dynamic type : B &

in the last line

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[Bug python/14077] Dynamic type of references cannot be accessed

[andre.poenitz at nokia dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=14077

--- Comment #1 from Andre Poenitz <andre.poenitz at nokia dot com> 2012-05-08 17:01:31 UTC ---

The following seems to fix the issue for me:

diff --git a/gdb/python/py-value.c b/gdb/python/py-value.c
index 6f67bdb..bfb7260 100644
--- a/gdb/python/py-value.c
+++ b/gdb/python/py-value.c
@@ -310,7 +310,11 @@ valpy_get_dynamic_type (PyObject *self, void *closure)
          struct value *target;
          int was_pointer = TYPE_CODE (type) == TYPE_CODE_PTR;

-         target = value_ind (val);
+         if (was_pointer)
+           target = value_ind (val);
+         else
+           target = coerce_ref (val);
+
          type = value_rtti_type (target, NULL, NULL, NULL);

          if (type)

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[Bug python/14077] Dynamic type of references cannot be accessed

[tromey at redhat dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=14077

Tom Tromey <tromey at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |tromey at redhat dot com

--- Comment #2 from Tom Tromey <tromey at redhat dot com> ---
Thread is here:
http://sourceware.org/ml/gdb-patches/2012-05/msg00394.html

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[Bug python/14077] Dynamic type of references cannot be accessed

[poenitz at htwm dot de]

https://sourceware.org/bugzilla/show_bug.cgi?id=14077

Andre' <poenitz at htwm dot de> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |poenitz at htwm dot de

--- Comment #3 from Andre' <poenitz at htwm dot de> ---
There has been another patch on the list, see
https://sourceware.org/ml/gdb-patches/2014-03/msg00542.html

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[Bug python/14077] Dynamic type of references cannot be accessed

[ssbssa at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=14077

Hannes Domani <ssbssa at sourceware dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |ssbssa at sourceware dot org
             Status|NEW                         |RESOLVED
   Target Milestone|---                         |7.8
         Resolution|---                         |FIXED

--- Comment #4 from Hannes Domani <ssbssa at sourceware dot org> ---
Fixed since version 7.8, with this commit:
https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=7af389b892404edc76e1a60c59b354b785378fa5

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