Detect simple tail calls

This CL contains the first steps towards tail call optimization:

  * Structurally detect tail calls during instruction selection,
    looking for special return/call combinations.

  * Added new architecture-specific instructions for tail calls which
    jump instead of call and take care of frame adjustment.

  * Moved some code around.

Currently we restrict tail calls to callees which only use registers
for arguments/return value and to call sites which are explicitly
marked as being OK for tail calls. This excludes, among other things,
call sites in sloppy JS functions and our IC machinery (both need in
general to be able to access the caller's frame).

All this is behind a flag --turbo-tail-calls, which is currently off
by default, so it can easily be toggled.

Review URL: https://codereview.chromium.org/1108563002

Cr-Commit-Position: refs/heads/master@{#28150}
30 files changed
tree: 413ba7b56c0ab23448f1ef88f34b42eb997a0320
  1. benchmarks/
  2. build/
  3. include/
  4. samples/
  5. src/
  6. test/
  7. testing/
  8. third_party/
  9. tools/
  10. .clang-format
  11. .gitignore
  12. .ycm_extra_conf.py
  13. AUTHORS
  14. BUILD.gn
  15. ChangeLog
  16. codereview.settings
  17. DEPS
  18. LICENSE
  19. LICENSE.strongtalk
  20. LICENSE.v8
  21. LICENSE.valgrind
  22. Makefile
  23. Makefile.android
  24. Makefile.nacl
  25. OWNERS
  26. PRESUBMIT.py
  27. README.md
  28. WATCHLISTS
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/*