Since the empty string is canonical HeapObject now, we can use
this fact to optimize
- strict equality comparisons with the empty string to a
simple ReferenceEqual operation, and
- optimize ToBoolean to avoid instance type checks completely.
Drive-by-fix: Allow InternalizedString for Type::HeapConstant
in the type system. This is safe, since InternalizedStrings
can be compared to other heap constants by reference (except
for non-InternalizedStrings, which are excluded from the
HeapConstant type).
BUG=v8:5267
R=yangguo@chromium.org
Review-Url: https://codereview.chromium.org/2681273002
Cr-Commit-Position: refs/heads/master@{#43050}
cd9724d4b4