General GC optimizations (#3221)

- Enable recursive GC marking with a limited recursion count (this option is configurable)
- No need to decrease the reference count of the gray objects anymore
- Bound function object marking is seperated into a helper function

JerryScript-DCO-1.0-Signed-off-by: Robert Fancsik frobert@inf.u-szeged.hu

tools/build.py

@@ -128,6 +128,8 @@ def get_arguments():
                          help='memory usage limit to trigger garbage collection (in bytes)')
     coregrp.add_argument('--stack-limit', metavar='SIZE', type=int,
                          help='maximum stack usage (in kilobytes)')
+    coregrp.add_argument('--gc-mark-limit', metavar='SIZE', type=int,
+                         help='maximum depth of recursion during GC mark phase')
     coregrp.add_argument('--mem-stats', metavar='X', choices=['ON', 'OFF'], type=str.upper,
                          help=devhelp('enable memory statistics (%(choices)s)'))
     coregrp.add_argument('--mem-stress-test', metavar='X', choices=['ON', 'OFF'], type=str.upper,
@@ -215,6 +217,9 @@ def generate_build_options(arguments):
     build_options_append('JERRY_VALGRIND', arguments.valgrind)
     build_options_append('JERRY_VM_EXEC_STOP', arguments.vm_exec_stop)
 
+    if arguments.gc_mark_limit is not None:
+        build_options.append('-D%s=%s' % ('JERRY_GC_MARK_LIMIT', arguments.gc_mark_limit))
+
     # jerry-main options
     build_options_append('ENABLE_LINK_MAP', arguments.link_map)