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-rw-r--r--js/src/gdb/mozilla/JSObject.py119
1 files changed, 119 insertions, 0 deletions
diff --git a/js/src/gdb/mozilla/JSObject.py b/js/src/gdb/mozilla/JSObject.py
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+++ b/js/src/gdb/mozilla/JSObject.py
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+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this file,
+# You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Pretty-printers for SpiderMonkey JSObjects.
+
+import re
+
+import gdb
+
+import mozilla.prettyprinters as prettyprinters
+from mozilla.CellHeader import get_header_ptr
+from mozilla.jsval import JSValue
+from mozilla.prettyprinters import ptr_pretty_printer, ref_pretty_printer
+
+prettyprinters.clear_module_printers(__name__)
+
+
+class JSObjectTypeCache(object):
+ def __init__(self):
+ object_flag = gdb.lookup_type("js::ObjectFlag")
+ self.objectflag_IsUsedAsPrototype = prettyprinters.enum_value(
+ object_flag, "js::ObjectFlag::IsUsedAsPrototype"
+ )
+ self.value_ptr_t = gdb.lookup_type("JS::Value").pointer()
+ self.func_ptr_t = gdb.lookup_type("JSFunction").pointer()
+ self.class_NON_NATIVE = gdb.parse_and_eval("JSClass::NON_NATIVE")
+ self.BaseShape_ptr_t = gdb.lookup_type("js::BaseShape").pointer()
+ self.Shape_ptr_t = gdb.lookup_type("js::Shape").pointer()
+ self.JSClass_ptr_t = gdb.lookup_type("JSClass").pointer()
+ self.JSScript_ptr_t = gdb.lookup_type("JSScript").pointer()
+ self.JSFunction_AtomSlot = gdb.parse_and_eval("JSFunction::AtomSlot")
+ self.JSFunction_NativeJitInfoOrInterpretedScriptSlot = gdb.parse_and_eval(
+ "JSFunction::NativeJitInfoOrInterpretedScriptSlot"
+ )
+
+
+# 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()
+ self.otc = cache.mod_JSObject
+
+ def summary(self):
+ shape = get_header_ptr(self.value, self.otc.Shape_ptr_t)
+ baseshape = get_header_ptr(shape, self.otc.BaseShape_ptr_t)
+ classp = get_header_ptr(baseshape, self.otc.JSClass_ptr_t)
+ 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:
+ flags = shape["objectFlags_"]["flags_"]
+ used_as_prototype = bool(flags & self.otc.objectflag_IsUsedAsPrototype)
+ 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
+ name = get_function_name(function, self.cache)
+ return "[object {}{}]{}".format(
+ class_name,
+ " " + name if name else "",
+ " used_as_prototype" if used_as_prototype else "",
+ )
+
+
+def get_function_name(function, cache):
+ if not cache.mod_JSObject:
+ cache.mod_JSObject = JSObjectTypeCache()
+ otc = cache.mod_JSObject
+
+ function = function.cast(otc.func_ptr_t)
+ fixed_slots = (function + 1).cast(otc.value_ptr_t)
+ atom_value = JSValue(fixed_slots[otc.JSFunction_AtomSlot], cache)
+
+ if atom_value.is_undefined():
+ return "<unnamed>"
+
+ return str(atom_value.get_string())
+
+
+def get_function_script(function, cache):
+ if not cache.mod_JSObject:
+ cache.mod_JSObject = JSObjectTypeCache()
+ otc = cache.mod_JSObject
+
+ function = function.cast(otc.func_ptr_t)
+ fixed_slots = (function + 1).cast(otc.value_ptr_t)
+ slot = otc.JSFunction_NativeJitInfoOrInterpretedScriptSlot
+ script_value = JSValue(fixed_slots[slot], cache)
+
+ if script_value.is_undefined():
+ return 0
+
+ return script_value.get_private()
+
+
+@ref_pretty_printer("JSObject")
+def JSObjectRef(value, cache):
+ return JSObjectPtrOrRef(value, cache)