[coverage] Add dedicated FunctionLiteral counters

Prior to this CL, call counts at function scope were taken from the
FeedbackVector::invocation_count field. This had two major drawbacks:
1. for generator functions, these count the number of resumptions
instead of the number of calls; and 2. the invocation count is not
maintained in optimized code.

The solution implemented here is to add a dedicated call counter at
function scope which is incremented exactly once each time the
function is called.

A minor complication is that our coverage output format expects
function-scope counts in the dedicated CoverageFunction object, and
not as a CoverageBlock. Thus function-scope block counts are initially
marked with magic positions, and later recognized and rewritten during
processing.

This CL thus fixes reported generator function call counts and enables
optimizations in block coverage modes (more to come in a follow-up).

Drive-by: Don't report functions with empty source ranges.

Bug: v8:6000,v8:9148,v8:9212
Cq-Include-Trybots: luci.chromium.try:linux_layout_tests_layout_ng
Change-Id: Idbe5edb35a595cf12b6649314738ac00efd173b8
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1613996
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61574}
11 files changed
tree: ef36f744d86eeac51b4576b0901a8af0cc72aab2
  1. .clang-format
  2. .clang-tidy
  3. .editorconfig
  4. .git-blame-ignore-revs
  5. .gitattributes
  6. .gitignore
  7. .gn
  8. .vpython
  9. .ycm_extra_conf.py
  10. AUTHORS
  11. BUILD.gn
  12. CODE_OF_CONDUCT.md
  13. ChangeLog
  14. DEPS
  15. ENG_REVIEW_OWNERS
  16. INFRA_OWNERS
  17. LICENSE
  18. LICENSE.fdlibm
  19. LICENSE.strongtalk
  20. LICENSE.v8
  21. LICENSE.valgrind
  22. OWNERS
  23. PRESUBMIT.py
  24. README.md
  25. WATCHLISTS
  26. benchmarks/
  27. build_overrides/
  28. codereview.settings
  29. custom_deps/
  30. docs/
  31. gni/
  32. include/
  33. infra/
  34. samples/
  35. snapshot_toolchain.gni
  36. src/
  37. test/
  38. testing/
  39. third_party/
  40. 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://v8.dev/docs

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 at v8.dev/docs/contribute.