Right now the implementation of `Isolate.spawnUri(<uri>, ...)` in
the standalone embedder is to ignore `<uri>` and make the spawnned
isolate from the same AOT snapshot as the main isolate.
This is very confusing and very incorrect.
Instead `Isolate.spawnUri()` should work if-and-only-if the given
`<uri>` points to a valid and compatible AOT snapshot. If not, it should
throw an appropriate exception.
Fixes https://github.com/dart-lang/sdk/issues/48375
Fixes https://github.com/dart-lang/sdk/issues/48326
TEST=vm/dart{,_2}/spawn_uri_aot_test
Change-Id: I279ace08ac1b9a9eed3ae03ebe5d9e2336c1e5c9
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/232603
Reviewed-by: Tess Strickland <sstrickl@google.com>
Commit-Queue: Martin Kustermann <kustermann@google.com>
This CL implements `WeakReference` in the VM.
* This reduces the size of weak references from 2 objects using 8 words
to 1 object using 4 words.
* This makes loads of weak reference targets a single load instead of
two.
* This avoids the fix-point in the GC and message object copying for
weak references. (N.b. Weak references need to be processed _after_
the fix-point for weak properties.)
The semantics of weak references in messages is that their target gets
set to `null` if the target is not included in the message by a strong
reference.
The tests take particular care to exercise the case where a weak
reference's target is only kept alive because a weak property key is
alive and it refers to the target in its value. This exercises the fact
that weak references need to be processed last.
Does not add support for weak references in the app snapshot. It would
be dead code until we start using weak references in for example the
CFE.
This CL does not try to unify weak references and weak properties in
the GC or messaging (as proposed in go/dart-vm-weakreference), because
their semantics differ enough.
Closes: https://github.com/dart-lang/sdk/issues/48162
TEST=runtime/tests/vm/dart/finalizer/weak_reference_run_gc_test.dart
TEST=runtime/tests/vm/dart/isolates/fast_object_copy_test.dart
TEST=runtime/vm/object_test.cc
TEST=tests/lib/isolate/weak_reference_message_1_test.dart
TEST=tests/lib/isolate/weak_reference_message_2_test.dart
Change-Id: I3810e919a5866f3ae8a95bd9aa23a880a0b0921c
Cq-Include-Trybots: luci.dart.try:app-kernel-linux-debug-x64-try,dart-sdk-mac-arm64-try,vm-canary-linux-debug-try,vm-fuchsia-release-x64-try,vm-kernel-gcc-linux-try,vm-kernel-asan-linux-release-x64-try,vm-kernel-linux-debug-x64c-try,vm-kernel-linux-debug-x64-try,vm-kernel-linux-debug-simriscv64-try,vm-kernel-mac-debug-x64-try,vm-kernel-nnbd-linux-debug-x64-try,vm-kernel-nnbd-linux-release-ia32-try,vm-kernel-nnbd-linux-release-simarm64-try,vm-kernel-nnbd-linux-release-simarm-try,vm-kernel-nnbd-mac-debug-arm64-try,vm-kernel-nnbd-mac-debug-x64-try,vm-kernel-nnbd-win-release-ia32-try,vm-kernel-nnbd-win-release-x64-try,vm-kernel-optcounter-threshold-linux-release-x64-try,vm-kernel-precomp-android-release-arm_x64-try,vm-kernel-precomp-linux-debug-x64-try,vm-kernel-precomp-linux-debug-x64c-try,vm-kernel-precomp-win-debug-x64c-try,vm-kernel-reload-rollback-linux-debug-x64-try,vm-kernel-reload-linux-debug-x64-try,vm-kernel-win-debug-ia32-try,vm-kernel-win-debug-x64-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/232087
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
Commit-Queue: Daco Harkes <dacoharkes@google.com>
Robert Nystrom