[turbofan] Optimistic slack tracking completion.

The idea is to compute the slack before compilation start. Then
we check that the slack tracking decision is the same at the end
of compilation. If it is, we just commit to that slack tracking
(by calling function->CompleteInobjectSlackTrackingIfActive).
If the slack tracking decision changed, we will retry the compilation.

This has several pieces:
- Expose computation of slack and instance size from the object model.
- Add compilation dependency on the slack tracking result.
- Change create lowering to use the dependency.
- Fix array creation to use the slack tracking result's instance

Bug: v8:7790
Change-Id: Id975300cfd6c1786733cd7cbf55cc507c05738b2
Reviewed-on: https://chromium-review.googlesource.com/1164957
Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54982}
9 files changed
tree: e2b8614d1a1ea65a4f64f4025192c84831dc95ef
  1. .clang-format
  2. .editorconfig
  3. .git-blame-ignore-revs
  4. .gitattributes
  5. .gitignore
  6. .gn
  7. .vpython
  8. .ycm_extra_conf.py
  10. BUILD.gn
  12. ChangeLog
  13. DEPS
  15. LICENSE.fdlibm
  16. LICENSE.strongtalk
  17. LICENSE.v8
  18. LICENSE.valgrind
  19. OWNERS
  20. PRESUBMIT.py
  21. README.md
  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/

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/*


Please follow the instructions mentioned on the V8 wiki.