deps: backport 2bd7464 from upstream V8
Checklist
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make -j4 test
(UNIX), orvcbuild test
(Windows) passes -
tests and/or benchmarks are included -
commit message follows commit guidelines
Affected core subsystem(s)
deps
Description of change
Backport of bugfix from upstream V8
Original commit message: 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}
V8 commit: v8/v8@2bd7464