tree ee4d07c0fa22abf446a1b45955e9bc801dce8d10
parent 56490f9776e93b6bb42e95b92bfef3b22e8d0b77
author Vyacheslav Egorov <vegorov@google.com> 1634124926 +0000
committer commit-bot@chromium.org <commit-bot@chromium.org> 1634124926 +0000

[vm/aot] Allow dropping dyn:-forwarder targets

Currently there is a strong link between dyn:-forwarder and
its target (through Function::data_ field). This link causes us
to retain some Function objects even if they are otherwise
considered dropped.

In reality this link is only ever used during compilation
or when accessing script information for the dyn:-forwarder.

As such when generating snapshots in DWARF stack traces mode
we should be able to consider this connection weak
and allow dropped Function objects to be truly discarded from
the snapshot.

This change puts WSR in between dyn:-forwarder and its target
when we know that target is not going to be retained.

We also clean how forwarding target represented to avoid
unnecessary indirection through a one-element array.

TEST=ci

Cq-Include-Trybots: luci.dart.try:vm-kernel-precomp-dwarf-linux-product-x64-try,vm-kernel-precomp-linux-debug-x64-try,vm-kernel-precomp-linux-release-x64-try
Change-Id: I4f0ec822ff15f78c72ff55a87d9dc52abd466cb3
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/216040
Commit-Queue: Slava Egorov <vegorov@google.com>
Reviewed-by: Alexander Markov <alexmarkov@google.com>