This CL demonstrates minimum valuable addition to existing debug evaluate
without side effects mechanism.
With this CL user can evaluate expressions like:
[a,b] // create any kind of temporary array literals
[a,b].reduce((x,y) => x + y, 0); // use reduce method
[1,2,3].fill(2); // change temporary arrays
The core idea: any change of the object created during evaluation without
side effects is side effect free. As soon as we try to store this temporary
object to object existed before evaluation we will terminate execution.
Implementation:
- track all objects allocated during evaluation and mark them as temporary,
- patch all bytecodes which change objects.
A little more details (including performance analysis): [1].
[1] https://docs.google.com/document/d/10qqAtZADspPnpYa6SEdYRxrddfKIZJIzbLtGpsZQkRo/edit#
Bug: v8:7588
Change-Id: I69f7b96e1ebd7ad0022219e8213211c7be72a111
Reviewed-on: https://chromium-review.googlesource.com/972615
Commit-Queue: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52370}
