[Interpreter] Optimize BytecodeArrayBuilder and BytecodeArrayWriter.

This CL optimizes the code in BytecodeArrayBuilder and
BytecodeArrayWriter by making the following main changes:

 - Move operand scale calculation out of BytecodeArrayWriter to the
BytecodeNode constructor, where the decision on which operands are
scalable can generally be statically decided by the compiler.
 - Move the maximum register calculation out of BytecodeArrayWriter
and into BytecodeRegisterOptimizer (which is the only place outside
BytecodeGenerator which updates which registers are used). This
avoids the BytecodeArrayWriter needing to know the operand types
of a node as it writes it.
 - Modify EmitBytecodes to use individual push_backs rather than
building a buffer and calling insert, since this turns out to be faster.
 - Initialize BytecodeArrayWriter's bytecode vector by reserving 512
bytes,
 - Make common functions in Bytecodes constexpr so that they
can be statically calculated by the compiler.
 - Move common functions and constructors in Bytecodes and
BytecodeNode to the header so that they can be inlined.
 - Change large static switch statements in Bytecodes to const array
lookups, and move to the header to allow inlining.

I also took the opportunity to remove a number of unused helper
functions, and rework some others for consistency.

This reduces the percentage of time spent in making BytecodeArrays
 in  CodeLoad from ~15% to ~11% according to perf. The
CoadLoad score increase by around 2%.

BUG=v8:4280

Review-Url: https://codereview.chromium.org/2351763002
Cr-Commit-Position: refs/heads/master@{#39599}
25 files changed
tree: 4f69f6e7309d0a802b19ee3392bc84685fcc373b
  1. benchmarks/
  2. build_overrides/
  3. docs/
  4. gni/
  5. gypfiles/
  6. include/
  7. infra/
  8. samples/
  9. src/
  10. test/
  11. testing/
  12. third_party/
  13. tools/
  14. .clang-format
  15. .gitignore
  16. .gn
  17. .ycm_extra_conf.py
  18. AUTHORS
  19. BUILD.gn
  20. ChangeLog
  21. CODE_OF_CONDUCT.md
  22. codereview.settings
  23. DEPS
  24. LICENSE
  25. LICENSE.fdlibm
  26. LICENSE.strongtalk
  27. LICENSE.v8
  28. LICENSE.valgrind
  29. Makefile
  30. Makefile.android
  31. OWNERS
  32. PRESUBMIT.py
  33. README.md
  34. snapshot_toolchain.gni
  35. 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://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.