Commit 3556c233 authored by Paolo Bonzini's avatar Paolo Bonzini Committed by Anthony Liguori
Browse files

qom: allow turning cast debugging off 



Cast debugging can have a substantial cost (20% or more).  Instead of adding
special-cased "fast casts" in the hot paths, we can just disable it in
releases.  The tracing facilities we just added make it easier to analyze
those problems that cast debugging would reveal.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Message-id: 1368188203-3407-7-git-send-email-pbonzini@redhat.com
Signed-off-by: default avatarAnthony Liguori <aliguori@us.ibm.com>
parent fa131d94

configure

+9 −0
Original line number Diff line number Diff line
@@ -220,6 +220,7 @@ blobs="yes" 
pkgversion=""

pie=""

zero_malloc=""

qom_cast_debug="yes"

trace_backend="nop"

trace_file="trace"

spice=""
@@ -688,6 +689,10 @@ for opt do 
  ;;

  --enable-sdl) sdl="yes"

  ;;

  --disable-qom-cast-debug) qom_cast_debug="no"

  ;;

  --enable-qom-cast-debug) qom_cast_debug="yes"

  ;;

  --disable-virtfs) virtfs="no"

  ;;

  --enable-virtfs) virtfs="yes"
@@ -3575,6 +3580,7 @@ echo "gcov enabled $gcov" 
echo "TPM support       $tpm"

echo "libssh2 support   $libssh2"

echo "TPM passthrough   $tpm_passthrough"

echo "QOM debugging     $qom_cast_debug"



if test "$sdl_too_old" = "yes"; then

echo "-> Your SDL version is too old - please upgrade to have SDL support"
@@ -3909,6 +3915,9 @@ echo "CONFIG_UNAME_RELEASE=\"$uname_release\"" >> $config_host_mak 
if test "$zero_malloc" = "yes" ; then

  echo "CONFIG_ZERO_MALLOC=y" >> $config_host_mak

fi

if test "$qom_cast_debug" = "yes" ; then

  echo "CONFIG_QOM_CAST_DEBUG=y" >> $config_host_mak

fi

if test "$rbd" = "yes" ; then

  echo "CONFIG_RBD=y" >> $config_host_mak

fi

include/qom/object.h

+6 −5
Original line number Diff line number Diff line
@@ -615,8 +615,9 @@ Object *object_dynamic_cast(Object *obj, const char *typename); 
 *

 * See object_dynamic_cast() for a description of the parameters of this

 * function.  The only difference in behavior is that this function asserts

 * instead of returning #NULL on failure.  This function is not meant to be

 * called directly, but only through the wrapper macro OBJECT_CHECK.

 * instead of returning #NULL on failure if QOM cast debugging is enabled.

 * This function is not meant to be called directly, but only through

 * the wrapper macro OBJECT_CHECK.

 */

Object *object_dynamic_cast_assert(Object *obj, const char *typename,

                                   const char *file, int line, const char *func);
@@ -666,9 +667,9 @@ Type type_register(const TypeInfo *info); 
 *

 * See object_class_dynamic_cast() for a description of the parameters

 * of this function.  The only difference in behavior is that this function

 * asserts instead of returning #NULL on failure.  This function is not

 * meant to be called directly, but only through the wrapper macros

 * OBJECT_CLASS_CHECK and INTERFACE_CHECK.

 * asserts instead of returning #NULL on failure if QOM cast debugging is

 * enabled.  This function is not meant to be called directly, but only through

 * the wrapper macros OBJECT_CLASS_CHECK and INTERFACE_CHECK.

 */

ObjectClass *object_class_dynamic_cast_assert(ObjectClass *klass,

                                              const char *typename,

qom/object.c

+11 −4
Original line number Diff line number Diff line
@@ -435,12 +435,11 @@ Object *object_dynamic_cast(Object *obj, const char *typename) 
Object *object_dynamic_cast_assert(Object *obj, const char *typename,

                                   const char *file, int line, const char *func)

{

    Object *inst;



    trace_object_dynamic_cast_assert(obj ? obj->class->type->name : "(null)",

                                     typename, file, line, func);



    inst = object_dynamic_cast(obj, typename);

#ifdef CONFIG_QOM_CAST_DEBUG

    Object *inst = object_dynamic_cast(obj, typename);



    if (!inst && obj) {

        fprintf(stderr, "%s:%d:%s: Object %p is not an instance of type %s\n",
@@ -448,7 +447,9 @@ Object *object_dynamic_cast_assert(Object *obj, const char *typename, 
        abort();

    }



    return inst;

    assert(obj == inst);

#endif

    return obj;

}



ObjectClass *object_class_dynamic_cast(ObjectClass *class,
@@ -509,6 +510,12 @@ ObjectClass *object_class_dynamic_cast_assert(ObjectClass *class, 
    trace_object_class_dynamic_cast_assert(class ? class->type->name : "(null)",

                                           typename, file, line, func);



#ifndef CONFIG_QOM_CAST_DEBUG

    if (!class->interfaces) {

        return class;

    }

#endif



    ret = object_class_dynamic_cast(class, typename);

    if (!ret && class) {

        fprintf(stderr, "%s:%d:%s: Object %p is not an instance of type %s\n",