This reverts commit 02849fd9de.
Reason for revert: Breaks Win64 MSVC bot and closes the tree - https://ci.chromium.org/p/v8/builders/ci/V8%20Win64%20-%20msvc/15416
Original change's description:
> cppgc-js: Add snapshot for C++ objects
>
> The following implements a snapshotting algorithm for C++ objects that
> also filters strongly-connected components (SCCs) of only "hidden"
> objects that are not (transitively) referencing any non-hidden
> objects.
>
> C++ objects come in two versions.
> a. Named objects that have been assigned a name through NameProvider.
> b. Unnamed objects, that are potentially hidden if the build
> configuration requires Oilpan to hide such names. Hidden objects have
> their name set to NameProvider::kHiddenName.
>
> The main challenge for the algorithm is to avoid blowing up the final
> object graph with hidden nodes that do not carry information. For that
> reason, the algorithm filters SCCs of only hidden objects, e.g.:
> ... -> (object) -> (object) -> (hidden) -> (hidden)
> In this case the (hidden) objects are filtered from the graph. The
> trickiest part is maintaining visibility state for objects referencing
> other objects that are currently being processed.
>
> Main algorithm idea (two passes):
> 1. First pass marks all non-hidden objects and those that transitively
> reach non-hidden objects as visible. Details:
> - Iterate over all objects.
> - If object is non-hidden mark it as visible and also mark parent
> as visible if needed.
> - If object is hidden, traverse children as DFS to find non-hidden
> objects. Post-order process the objects and mark those objects as
> visible that have child nodes that are visible themselves.
> - Maintain an epoch counter (StateStorage::state_count_) to allow
> deferring the visibility decision to other objects in the same
> SCC. This is similar to the "lowlink" value in Tarjan's algorithm
> for SCC.
> - After the first pass it is guaranteed that all deferred
> visibility decisions can be resolved.
> 2. Second pass adds nodes and edges for all visible objects.
> - Upon first checking the visibility state of an object, all deferred
> visibility states are resolved.
>
> For practical reasons, the recursion is transformed into an iteration.
> We do not use plain Tarjan's algorithm to avoid another pass over
> all nodes to create SCCs.
>
> Follow ups:
> 1. Adding wrapper nodes for cpp objects that are wrappables for V8
> wrappers.
> 2. Adding detachedness information.
>
> Change-Id: I6e127d2c6d65e77defe08e39295a2594f463b962
> Bug: chromium:1056170
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2467854
> Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Reviewed-by: Omer Katz <omerkatz@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#70567}
TBR=ulan@chromium.org,mlippautz@chromium.org,bikineev@chromium.org,omerkatz@chromium.org
Change-Id: I64a2cf2259bdaed81f6e0f92bdcc7a1f0df4d197
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:1056170
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2479471
Reviewed-by: Maya Lekova <mslekova@chromium.org>
Commit-Queue: Maya Lekova <mslekova@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70571}
fba14bde5f