[turbofan] Handle CheckHeapObject as rename in LoadElimination.

Thus far the LoadElimination didn't consider CheckHeapObject a renaming
operation and would therefore miss opportunities to eliminate redundant
loads or map checks where the input is not checked for sminess in all
cases. This kind of pattern is very common with code that results from
builtin inlining in JSCallReducer, as here we don't unconditionally
insert CheckHeapObject nodes if we can tell from the graph that the
receiver already has a certain map (by walking the effect chain
upwards).

Bug: v8:8070
Change-Id: I980f382205757a754f93a5741de1ee08b75ee070
Reviewed-on: https://chromium-review.googlesource.com/1188129
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55408}
1 file changed
tree: f3bd25610b43c6d222876709d0c1625a02994f10
  1. .clang-format
  2. .editorconfig
  3. .git-blame-ignore-revs
  4. .gitattributes
  5. .gitignore
  6. .gn
  7. .vpython
  8. .ycm_extra_conf.py
  9. AUTHORS
  10. BUILD.gn
  11. CODE_OF_CONDUCT.md
  12. ChangeLog
  13. DEPS
  14. LICENSE
  15. LICENSE.fdlibm
  16. LICENSE.strongtalk
  17. LICENSE.v8
  18. LICENSE.valgrind
  19. OWNERS
  20. PRESUBMIT.py
  21. README.md
  22. WATCHLISTS
  23. benchmarks/
  24. build_overrides/
  25. codereview.settings
  26. custom_deps/
  27. docs/
  28. gni/
  29. include/
  30. infra/
  31. samples/
  32. snapshot_toolchain.gni
  33. src/
  34. test/
  35. testing/
  36. third_party/
  37. tools/
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://github.com/v8/v8/wiki

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/*

Contributing

Please follow the instructions mentioned on the V8 wiki.