https://bugs.webkit.org/show_bug.cgi?id=115920

Reviewed by Mark Hahnenberg.

We don't yet support watchpoints, but this does all the wiring right up to the
part where we would have emitted watchpoints. I've also written this in a way that
makes it easy to use the case where you would have anyway speculated non-masquerading
even if the watchpoint was invalidated.

This is inherently racy, of course: but the only race here is that you might first
set the watchpoint, and then the watchpoint is invalidated, and then you compile rest
of the code in a way that doesn't need the watchpoint. That's fine, since the FTL
will remember that it had set the watchpoint and then cancel the compilation.

* ftl/FTLAbbreviations.h:
(JSC::FTL::int8Type):
* ftl/FTLAbstractHeapRepository.h:
(FTL):
* ftl/FTLCommonValues.cpp:
(JSC::FTL::CommonValues::CommonValues):
* ftl/FTLCommonValues.h:
(CommonValues):
* ftl/FTLLowerDFGToLLVM.cpp:
(JSC::FTL::LowerDFGToLLVM::compileCompareEq):
(JSC::FTL::LowerDFGToLLVM::lowNonNullObject):
(LowerDFGToLLVM):
(JSC::FTL::LowerDFGToLLVM::speculateNonNullObject):
(JSC::FTL::LowerDFGToLLVM::masqueradesAsUndefinedWatchpointIsStillValid):
(JSC::FTL::LowerDFGToLLVM::masqueradesAsUndefinedWatchpointIfIsStillValid):
* ftl/FTLOutput.h:
(JSC::FTL::Output::constInt8):
(JSC::FTL::Output::load8):
(JSC::FTL::Output::isZero8):
(JSC::FTL::Output::notZero8):
(JSC::FTL::Output::testIsZero8):
(JSC::FTL::Output::testNonZero8):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153149 268f45cc-cd09-0410-ab3c-d52691b4dbfc