Reland "[builtins] Verify Isolate compatibility with the embedded blob"

This is a reland of b022e825bd9f45279bb0c493a9081804f17455ae

Original change's description:
> [builtins] Verify Isolate compatibility with the embedded blob
> Embedded builtins (= the embedded blob) have a few dependencies on the
> snapshot state. For instance, they require that metadata stored on
> builtin Code objects as well as the builtins constant table remain
> unchanged from mksnapshot-time. Embedders may violate these
> assumptions by accident, e.g. by loading a snapshot generated with
> different build flags, leading to seemingly unrelated failures later
> on.
> This CL introduces an Isolate hash stored in the embedded blob which
> hashes relevant parts of builtin Code objects and the builtins
> constant table. It's verified in Isolate::Init in debug builds.
> Bug: v8:8723
> Change-Id: Ifc9bdbe6f56ea67d8984f162afa73a3572cfbba8
> Reviewed-on:
> Commit-Queue: Jakob Gruber <>
> Reviewed-by: Sigurd Schneider <>
> Cr-Commit-Position: refs/heads/master@{#59177}

Bug: v8:8723
Change-Id: I1dd001783f0f1fae21a9809c8639e40f55b8f663
Commit-Queue: Jakob Gruber <>
Reviewed-by: Jakob Gruber <>
Reviewed-by: Sigurd Schneider <>
Cr-Commit-Position: refs/heads/master@{#59236}
5 files changed
tree: bb95b88e1824df108642e100e7ed50daa0bae9fd
  1. .clang-format
  2. .clang-tidy
  3. .editorconfig
  4. .git-blame-ignore-revs
  5. .gitattributes
  6. .gitignore
  7. .gn
  8. .vpython
  13. ChangeLog
  14. DEPS
  16. LICENSE.fdlibm
  17. LICENSE.strongtalk
  18. LICENSE.v8
  19. LICENSE.valgrind
  20. OWNERS
  24. benchmarks/
  25. build_overrides/
  26. codereview.settings
  27. custom_deps/
  28. docs/
  29. gni/
  30. include/
  31. infra/
  32. samples/
  33. snapshot_toolchain.gni
  34. src/
  35. test/
  36. testing/
  37. third_party/
  38. 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:

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.