BUG=v8:8801

Change-Id: I9d9d9824c6c9ad0176bbfd3723da1b578b17c256
Reviewed-on: https://chromium-review.googlesource.com/c/1495555
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Mythri Alle <mythria@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60001}

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}

Increase from 2^28 - 16 to 2^30 - 25 for 64-bit platforms.

Bug: v8:6148
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_chromium_rel_ng
Change-Id: I3529d7ed757a7ab49a001af8641cf888db171cdb
Reviewed-on: https://chromium-review.googlesource.com/570047Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46838}

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}