1 files changed, 68 insertions, 0 deletions
diff --git a/js/src/gdb/mozilla/JSObject.py b/js/src/gdb/mozilla/JSObject.py
new file mode 100644
index 000000000..8112a9d36
--- /dev/null
+++ b/js/src/gdb/mozilla/JSObject.py
@@ -0,0 +1,68 @@
+# Pretty-printers for SpiderMonkey JSObjects.
+
+import re
+import gdb
+import mozilla.JSString
+import mozilla.prettyprinters as prettyprinters
+from mozilla.prettyprinters import ptr_pretty_printer, ref_pretty_printer
+from mozilla.Root import deref
+
+prettyprinters.clear_module_printers(__name__)
+
+class JSObjectTypeCache(object):
+    def __init__(self, value, cache):
+        baseshape_flags = gdb.lookup_type('js::BaseShape::Flag')
+        self.flag_DELEGATE = prettyprinters.enum_value(baseshape_flags, 'js::BaseShape::DELEGATE')
+        self.func_ptr_type = gdb.lookup_type('JSFunction').pointer()
+        self.class_NON_NATIVE = gdb.parse_and_eval('js::Class::NON_NATIVE')
+        self.NativeObject_ptr_t = gdb.lookup_type('js::NativeObject').pointer()
+
+# There should be no need to register this for JSFunction as well, since we
+# search for pretty-printers under the names of base classes, and
+# JSFunction has JSObject as a base class.
+
+gdb_string_regexp = re.compile(r'(?:0x[0-9a-z]+ )?(?:<.*> )?"(.*)"', re.I)
+
+@ptr_pretty_printer('JSObject')
+class JSObjectPtrOrRef(prettyprinters.Pointer):
+    def __init__(self, value, cache):
+        super(JSObjectPtrOrRef, self).__init__(value, cache)
+        if not cache.mod_JSObject:
+            cache.mod_JSObject = JSObjectTypeCache(value, cache)
+        self.otc = cache.mod_JSObject
+
+    def summary(self):
+        group = deref(self.value['group_'])
+        classp = group['clasp_']
+        non_native = classp['flags'] & self.otc.class_NON_NATIVE
+
+        # Use GDB to format the class name, but then strip off the address
+        # and the quotes.
+        class_name = str(classp['name'])
+        m = gdb_string_regexp.match(class_name)
+        if m:
+            class_name = m.group(1)
+
+        if non_native:
+            return '[object {}]'.format(class_name)
+        else:
+            native = self.value.cast(self.otc.NativeObject_ptr_t)
+            shape = deref(native['shape_'])
+            baseshape = deref(shape['base_'])
+            flags = baseshape['flags']
+            is_delegate = bool(flags & self.otc.flag_DELEGATE)
+            name = None
+            if class_name == 'Function':
+                function = self.value
+                concrete_type = function.type.strip_typedefs()
+                if concrete_type.code == gdb.TYPE_CODE_REF:
+                    function = function.address
+                function = function.cast(self.otc.func_ptr_type)
+                atom = deref(function['atom_'])
+                name = str(atom) if atom else '<unnamed>'
+            return '[object {}{}]{}'.format(class_name,
+                                            ' ' + name if name else '',
+                                            ' delegate' if is_delegate else '')
+
+@ref_pretty_printer('JSObject')
+def JSObjectRef(value, cache): return JSObjectPtrOrRef(value, cache)