The new node is introduced for literal string addition and calling
String.prototype.concat in the typed lowering phase. It later might get optimized
away during redundancy elimination, keeping the performance of already existing
benchmarks with string addition. In case the operation is about to throw
(due to too long string being constructed) we just deoptimize, reusing
the interpreter logic for creating the error.
Modify relevant mjsunit and unit tests for string concatenation.
Bug: v8:7902
Change-Id: Ie97d39534df4480fa8d4fe3ba276d02ed5e750e3
Reviewed-on: https://chromium-review.googlesource.com/1193342
Commit-Queue: Maya Lekova <mslekova@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55482}
Extract String feedback on Add operation and utilize to lower ConsString
creation in JSTypedLowering when we know that a String addition will
definitely result in the creation of a ConsString.
Note that Crankshaft has to guard the potential length overflow of the
resulting string with an eager deoptimization exit, while we can safely
throw an exception in that case.
Also note that the bytecode pipeline does not currently provide the
String feedback for the addition, which has to be added.
BUG=v8:5267
R=jarin@chromium.org
Review-Url: https://codereview.chromium.org/2354853002
Cr-Commit-Position: refs/heads/master@{#39540}
