On Tue, Dec 11, 2012 at 5:42 AM, <[email protected]> wrote: > Reviewers: Michael Starzinger, > > Description: > Object.observe: prevent observed objects from using fast elements. > > This is necessary because polymorphic stores generally > do not perform a map check but only an instance type check, > which misses out on changes in the observation status. > Unfortunately, there currently is no efficient way in V8 > to maintain that optimisation in the presence of Object.observe. >
Out of curiosity, how expensive would the additional map check be? I.e. how much would it regress relevant benchmarks? > > [email protected] > BUG= > > > Please review this at > https://codereview.chromium.**org/11477006/<https://codereview.chromium.org/11477006/> > > SVN Base: > https://v8.googlecode.com/svn/**branches/bleeding_edge<https://v8.googlecode.com/svn/branches/bleeding_edge> > > Affected files: > M src/objects-inl.h > M src/objects.cc > M src/runtime.cc > M test/mjsunit/harmony/object-**observe.js > M test/mjsunit/regress/regress-**observe-empty-double-array.js > > > -- v8-dev mailing list [email protected] http://groups.google.com/group/v8-dev
