Attachment 348436 Details for Bug 189070 – Patch

[patch] Patch

bug-189070-20180829151201.patch (text/plain), 2.79 KB, created by Daniel Bates on 2018-08-29 15:12:02 PDT

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Creator: Daniel Bates

Created: 2018-08-29 15:12:02 PDT

Size: 2.79 KB

patch

obsolete

>Subversion Revision: 235481
>diff --git a/Tools/ChangeLog b/Tools/ChangeLog
>index 8567aa4be6c6fb165718b79d4a57660909f71e6f..054a9a96958ce90eb62761547848c52f97fd1669 100644
>--- a/Tools/ChangeLog
>+++ b/Tools/ChangeLog
>@@ -1,3 +1,23 @@
>+2018-08-29  Daniel Bates  <dabates@apple.com>
>+
>+        lldb-webkit: KeyError thrown for uninitialized OptionSet
>+        https://bugs.webkit.org/show_bug.cgi?id=189070
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        Do not compute what enumerators are in an uninitialized OptionSet. A local OptionSet variable
>+        is only considered initialized when execution passes over its assignment regardless of whether
>+        the variable is in scope.
>+
>+        The LLDB Python API does not provide a way to determine whether an variable is initialized.
>+        So, we use a simple heuristic: when the value of the OptionSet is greater than the value
>+        of the bitmask with all enumerators set then we consider the OptionSet to be garbage (i.e.
>+        uninitialized memory). When the variable is finally initialized LLDB will notify us to update
>+        our state.
>+
>+        * lldb/lldb_webkit.py:
>+        (WTFOptionSetProvider.update):
>+
> 2018-08-29  Chris Dumez  <cdumez@apple.com>
> 
>         [PSON] We should only process-swap when eTLD+1 changes on navigation
>diff --git a/Tools/lldb/lldb_webkit.py b/Tools/lldb/lldb_webkit.py
>index 44d77bb5a76b930c5ddc786bc89f57aadf0f0d06..f4e1e2b9ca8a110868ba2a61bb376cfecedb168b 100644
>--- a/Tools/lldb/lldb_webkit.py
>+++ b/Tools/lldb/lldb_webkit.py
>@@ -612,16 +612,23 @@ class WTFOptionSetProvider:
>         return None
> 
>     def update(self):
>-        self.storage = self.valobj.GetChildMemberWithName('m_storage')
>+        self.storage = self.valobj.GetChildMemberWithName('m_storage')  # May be uninitialized memory
>+        self._elements = []
>+        self.size = 0
> 
>         template_argument_sbType = self.valobj.GetType().GetTemplateArgumentType(0)
>         enumerator_value_to_name_map = {sbTypeEnumMember.GetValueAsUnsigned(): sbTypeEnumMember.GetName() for sbTypeEnumMember in template_argument_sbType.get_enum_members_array()}
>         if not enumerator_value_to_name_map:
>             return
> 
>+        bitmask_with_all_options_set = sum(enumerator_value_to_name_map)
>+        bitmask = self.storage.GetValueAsUnsigned(0)
>+        if bitmask > bitmask_with_all_options_set:
>+            return  # self.valobj is uninitialized memory
>+
>+        # self.valobj looks like it contains a valid value.
>         # Iterate from least significant bit to most significant bit.
>         elements = []
>-        bitmask = self.storage.GetValueAsUnsigned(0)
>         while bitmask > 0:
>             current = bitmask & -bitmask  # Isolate the rightmost set bit.
>             elements.append((enumerator_value_to_name_map[current], current))  # e.g. ('Spelling', 4)

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simon.fraser: review+

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Attachments on bug 189070: 348363 | 348436