[ic] Also collect known map for relational comparison.

Previously we only collected the known map for equality comparisons. But
if we also collect it for relational comparisons, we can inline a fast
path of ToPrimitive on the objects, which is especially interesting
since both sides have the same map.

For now we only inline a very limited subset of ToPrimitive in
Crankshaft, which is when the receiver map (and its prototype chain)
doesn't have @@toPrimitive, and both valueOf and toString are the
default versions on the %ObjectPrototype%. In this case the relational
comparison would reduce to a string comparison of "[object CLASS]" with
itself and so we can reduce that to a boolean constant plus map checks
on both left and right hand side, plus code dependencies on the
prototype chain. This repairs the regression on box2d.


Review URL: https://codereview.chromium.org/1355113002

Cr-Commit-Position: refs/heads/master@{#30852}
13 files changed
tree: b3c7bcefe05f58bd7f4c380a9988f9f0fb594d21
  1. benchmarks/
  2. build/
  3. include/
  4. infra/
  5. samples/
  6. src/
  7. test/
  8. testing/
  9. third_party/
  10. tools/
  11. .clang-format
  12. .gitignore
  13. .ycm_extra_conf.py
  15. BUILD.gn
  16. ChangeLog
  17. codereview.settings
  18. DEPS
  20. LICENSE.strongtalk
  21. LICENSE.v8
  22. LICENSE.valgrind
  23. Makefile
  24. Makefile.android
  25. Makefile.nacl
  26. OWNERS
  27. PRESUBMIT.py
  28. README.md

V8 JavaScript Engine

V8 is Google's open source JavaScript engine.

V8 implements ECMAScript as specified in ECMA-262.

V8 is written in C++ and is used in Google Chrome, the open source browser from Google.

V8 can run standalone, or can be embedded into any C++ application.

V8 Project page: https://code.google.com/p/v8/

Getting the Code

Checkout depot tools, and run

    fetch v8

This will checkout V8 into the directory v8 and fetch all of its dependencies. To stay up to date, run

    git pull origin
    gclient sync

For fetching all branches, add the following into your remote configuration in .git/config:

    fetch = +refs/branch-heads/*:refs/remotes/branch-heads/*
    fetch = +refs/tags/*:refs/tags/*


Please follow the instructions mentioned on the V8 wiki.