For global object property cells, we did not check that the map on the
previous object is still the same for which we actually optimized. So
the optimized code was not in sync with the actual state of the property
cell. When loading from such a global object property cell, Crankshaft
optimizes away any map checks (based on the stable map assumption),
leading to arbitrary memory access in the worst case.
TurboFan has the same bug for stores, but is safe on loads because we
do appropriate map checks there. However mixing TurboFan and Crankshaft
still exposes the bug.
R=yangguo@chromium.org
BUG=chromium:659475
Review-Url: https://codereview.chromium.org/2444233004
Cr-Commit-Position: refs/heads/master@{#40592}
Reason for revert:
Breaks tree: http://build.chromium.org/p/client.v8/builders/V8%20Linux64%20GC%20Stress%20-%20custom%20snapshot/builds/8789
Original issue's description:
> [compiler] Properly validate stable map assumption for globals.
>
> For global object property cells, we did not check that the map on the
> previous object is still the same for which we actually optimized. So
> the optimized code was not in sync with the actual state of the property
> cell. When loading from such a global object property cell, Crankshaft
> optimizes away any map checks (based on the stable map assumption),
> leading to arbitrary memory access in the worst case.
>
> TurboFan has the same bug for stores, but is safe on loads because we
> do appropriate map checks there. However mixing TurboFan and Crankshaft
> still exposes the bug.
>
> R=yangguo@chromium.org
> BUG=chromium:659475
TBR=yangguo@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:659475
Review-Url: https://codereview.chromium.org/2454513003
Cr-Commit-Position: refs/heads/master@{#40582}
For global object property cells, we did not check that the map on the
previous object is still the same for which we actually optimized. So
the optimized code was not in sync with the actual state of the property
cell. When loading from such a global object property cell, Crankshaft
optimizes away any map checks (based on the stable map assumption),
leading to arbitrary memory access in the worst case.
TurboFan has the same bug for stores, but is safe on loads because we
do appropriate map checks there. However mixing TurboFan and Crankshaft
still exposes the bug.
R=yangguo@chromium.org
BUG=chromium:659475
Review-Url: https://codereview.chromium.org/2444233004
Cr-Commit-Position: refs/heads/master@{#40578}
