In particular, don't serialize a function if its code is used by the
dispatch table, but there's no need for the function object itself
at runtime like dynamic lookup or dynamic invocation forwarders.
However, just because the owning function is not needed at runtime,
it may be used during serialization for things like assembly label
creation. Thus, instead of just clearing out the Code's owner field,
we add a new WeakSerializationReference (WSR) object whose target is
the original contents of the owner field. The WSR allows the
serializer to access the original owner, but also signals to the
serializer that the target should not be serialized in AOT snapshots
unless there are additional strong (non-WSR) references.
If no strong references are found, then the references to the WSR
in the snapshot are replaced with a reference to a WSR that only
contains the class ID of the original target. The serializer creates
only one WSR per class ID.
If strong references are found, then the target is still serialized.
In this case, the WSR is dropped entirely and any reference to it is
replaced with a direct reference to the serialized target. Thus, WSRs
only exist in the precompiled runtime for targets with no strong
references.
Changes on the Flutter gallery in release mode:
arm7: total size -1.10%, isolate size -6.08%
arm8: total size -1.16%, isolate size -6.09%
Bug: https://github.com/dart-lang/sdk/issues/41052
Change-Id: I5b435ca71ef85f50fe3484789087471a91aa4fe2
Cq-Include-Trybots: luci.dart.try:vm-kernel-precomp-linux-release-x64-try,vm-kernel-precomp-linux-product-x64-try,vm-kernel-precomp-linux-release-simarm-try,vm-kernel-precomp-linux-release-simarm64-try,vm-kernel-precomp-linux-release-simarm_x64-try,vm-kernel-precomp-mac-release-simarm64-try,vm-kernel-precomp-win-release-x64-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/137104
Commit-Queue: Tess Strickland <sstrickl@google.com>
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
Reviewed-by: Daco Harkes <dacoharkes@google.com>
Running all existing tests with/without lazy async stacks ensures that
the existing functionality for --lazy-async-stacks does not regress.
There are still a few smaller things to be done in the debugger for lazy
async stacks.
This CL also ensures:
* The inner closure, i.e. AsyncClosure/AsyncGenClosure, is not
inlined if FLAG_lazy_async_stacks is on.
* Fixes a crash in dartkb mode, when the function of the Bytecode
object is null.
* Does a simple integration of the lazy async stacks in debugger.cc -
to ensure a stack is returned via vm-service.
Issue https://github.com/dart-lang/sdk/issues/37668
Change-Id: Ibc1e887a457e2c456ae65d9ed5fa92434f122a32
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/131825
Commit-Queue: Martin Kustermann <kustermann@google.com>
Reviewed-by: Ben Konyi <bkonyi@google.com>
This is done by collecting all frames on the current stack until an async/async* frame is hit
which has yielded before (i.e. is not in sync-async case).
From there on it finds the closure of the async/async* frame and starts traversing the listeners:
while (closure != null) {
yield_index = closure.context[Context::kAsyncJumpVarIndex]
pc = closure.function.code.pc_descriptors.LookupPcFromYieldIndex(yield_index);
<emit pc in frame>
closure = closure.context[Context::kAsyncCompleterVarIndex]._future._resultOrListeners.callback;
}
Bug: https://github.com/dart-lang/sdk/issues/37668
Change-Id: I97030d22e529bf8a74ecd30a8a2589cfe57ad330
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/122644
Commit-Queue: Clement Skau <cskau@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
Also fix stack trace collection to always include invisible frames. It can happen that a visible function is inlined into an invisible function, and we don't expand inlined frames until we print a stack trace.
dart2js product x64:
compile time: 12.459s
VMIsolate(CodeSize): 152292
Isolate(CodeSize): 3343117
ReadOnlyData(CodeSize): 3728928
Instructions(CodeSize): 8677600
Total(CodeSize): 15901937
->
compile time: 14.195s (+13%)
VMIsolate(CodeSize): 174034
Isolate(CodeSize): 3892418 (+16%)
ReadOnlyData(CodeSize): 5036320 (+35%)
Instructions(CodeSize): 8682624
Total(CodeSize): 17785396 (+12%)
R=asiva@google.com
Review-Url: https://codereview.chromium.org/2687143005 .
This CL improves the stack traces that accompany exceptions. Whenever an
async function is entered, we remember how we got there. This is similar
in spirit to package:stack_trace but the implementation is more efficient
and memory usage can be more easily reasoned about.
Tracking causal stack traces:
- [x] Upon entry to an async function, capture the synchronous stack trace prefix and store it into the closure.
- [x] Upon entry to an async* function, capture the synchronous stack trace prefix and store it into the closure.
- [x] Before returning from an async function, clear the Thread's asynchronous stack trace.
- [x] After resuming an async function, load the sychronous stack trace prefix into the Thread.
- [x] Filter stack traces to remove async machinery.
Service protocol changes:
- [x] Send causal async stack trace.
Observatory changes:
- [x] Display causal async stack trace below async functions.
Fixes https://github.com/dart-lang/sdk/issues/27661R=asiva@google.com, rmacnak@google.com
Comparisons: https://docs.google.com/a/google.com/document/d/10r6jEqr8OCiDZ4y9SYU_uOimcHiOGAZMly2ghTErALI/edit?usp=sharing
Review-Url: https://codereview.chromium.org/2646443005 .
Teagan Strickland