This adds a new option --clamp-contents to dmd.py. This replaces every value
contained in the memory contents in the log with a pointer to the start of a live
block, if the value is a pointer into the middle of that block. All other values
are replaced with 0. This conservative analysis makes it easier to determine
which blocks point to other blocks.
This implements a new "scan" mode for DMD that records the address
and contents of every live unsampled block in the DMD log. This
enables the low-level analysis of references from one block to
another, which can help leak investigations.
This conversion was done with the script:
find . -name '*.cpp' -o -name '*.h' -o -name '*.mm' -o -name '*.idl' | \
egrep -v 'cairo-win32-refptr.h|RefPtr.h|TestRefPtr.cpp' | \
xargs sed -i -e 's/mozilla::TemporaryRef</already_AddRefed</g' \
-e 's/TemporaryRef</already_AddRefed</g'
Manual fixups were performed in the following instances:
- We handled mfbt/RefPtr.h manually so as to not convert TemporaryRef itself
into already_AddRefed.
- The following files had explicit Move() calls added to make up for the lack
of a copy constructor on already_AddRefed:
dom/base/ImageEncoder.cpp
dom/media/MediaTaskQueue.{h,cpp}
dom/media/webaudio/PannerNode.cpp
- A redundant overload for MediaTaskQueue::Dispatch was deleted.
- A few manual fixups were required in mfbt/tests/TestRefPtr.cpp.
- Comments, using declarations, and forward declarations relating to
TemporaryRef in dom/canvas/ and gfx/layers/ were changed to refer to
already_AddRefed.
frame->Preserves3D() is whether the frame's parent has transform-style:
preserve-3d, which means that the frame is part of the same 3-D scene as
its parent. frame->Preserves3DChildren() is whether the frame itself
has transform-style: preserve-3d, which means that the frame is part of
the same 3-D scene as its children.
Neither of these are valid cases for doing off-main-thread (OMT)
animation because all of the layers in a preserve-3d scene are currently
siblings of each other, rather than preserving ancestor/descendant
relationships. This means that it's not valid to animate transform of
the parent on the compositor because the compositor animation won't
update any of its children that have layers. Likewise, it's not valid
to animate transform of the child on the compositor because the code
that sends transform information to the compositor doesn't handle the
accumulation of transforms needed to get the "right" transform for the
child (i.e., with the transforms of its ancestors up to the top of the
3-D scene merged in).
This means that we do OMT animation for slightly fewer cases with the
patch than we did without the patch. This means it's pretty low risk in
terms of correctness, although there's a chance it might regress
performance on one of the (somewhat limited) set of cases where the
optimization was valid. (Bug 779598 covers doing OMT animation for
preserve-3d cases, and depends on the work ongoing in bug 1097464.)
The animate-preserve3d-parent.html reftest doesn't fail without the
patch, since something seems to invalidate in the test; it was testing
the testcase that showed correct behavior when the mouse was moving, so
this isn't incredibly surprising (although that invalidation from mouse
movement is itself worth debugging). The animate-preserve3d-child.html
test does fail without the patch, though.
(With an initial transform of none instead of the 30deg transform, both
tests also show an invalidation bug without the patch.)
