Bug 1294633 - Implement gdb pretty-printer for mozilla::LinkedList, recognize StaticAutoPtr/StaticRefPtr in smartptr.py. r=tromey

python/gdbpp/gdbpp/__init__.py

@@ -18,6 +18,7 @@ class GeckoPrettyPrinter(object):
         GeckoPrettyPrinter.pp.add_printer(self.name, self.regexp, wrapped)
         return wrapped
 
+import gdbpp.linkedlist
 import gdbpp.owningthread
 import gdbpp.smartptr
 import gdbpp.string

python/gdbpp/gdbpp/linkedlist.py

@@ -0,0 +1,49 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# 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/.
+
+import gdb
+import itertools
+from gdbpp import GeckoPrettyPrinter
+
+# mfbt's LinkedList<T> is a doubly-linked list where the items in the list store
+# the next/prev pointers as part of themselves rather than the list structure be
+# its own independent data structure.  This means:
+# - Every item may belong to at most one LinkedList instance.
+# - For our pretty printer, we only want to pretty-print the LinkedList object
+#   itself.  We do not want to start printing every item in the list whenever
+#   we run into a LinkedListElement<T>.
+@GeckoPrettyPrinter('mozilla::LinkedList', '^mozilla::LinkedList<.*>$')
+class linkedlist_printer(object):
+    def __init__(self, value):
+        self.value = value
+        # mfbt's LinkedList has the elements of the linked list subclass from
+        # LinkedListElement<T>.  We want its pointer type for casting purposes.
+        #
+        # (We want to list pointers since we expect all of these objects to be
+        # complex enough that we don't want to automatically expand them.  The
+        # LinkedListElement type itself isn't small.)
+        self.t_ptr_type = value.type.template_argument(0).pointer()
+
+    def children(self):
+        # Walk mNext until we loop back around to the sentinel.  The sentinel
+        # item always exists and in the zero-length base-case mNext == sentinel,
+        # so extract that immediately and update it throughout the loop.
+        sentinel = self.value['sentinel']
+        pSentinel = sentinel.address
+        pNext = sentinel['mNext']
+        i = 0
+        while pSentinel != pNext:
+            list_elem = pNext.dereference()
+            list_value = pNext.cast(self.t_ptr_type)
+            yield ('%d' % i, list_value)
+            pNext = list_elem['mNext']
+            i += 1
+
+    def to_string(self):
+        return str(self.value.type)
+
+    def display_hint(self):
+        return 'array'

python/gdbpp/gdbpp/smartptr.py

@@ -24,6 +24,8 @@ class weak_ptr_printer(object):
 
         return '[(%s) %s]' % (weak_ptr.dynamic_type, weak_ptr)
 
+@GeckoPrettyPrinter('mozilla::StaticAutoPtr', '^mozilla::StaticAutoPtr<.*>$')
+@GeckoPrettyPrinter('mozilla::StaticRefPtr', '^mozilla::StaticRefPtr<.*>$')
 @GeckoPrettyPrinter('nsAutoPtr', '^nsAutoPtr<.*>$')
 @GeckoPrettyPrinter('nsCOMPtr', '^nsCOMPtr<.*>$')
 @GeckoPrettyPrinter('RefPtr', '^RefPtr<.*>$')