The V8 Inspector was sending an additional frame as part of async stack
traces for async functions, which pointed to the first executed `await`
in the async function. This is leaking an implementation detail of how
(and more precisely when) the inspector decides to collect this stack
trace. From the users perspective the async part of the stack trace is
supposed to capture what happened _prior to the task_ - meaning in case
of async functions: What lead to the execution of the async function.
This is reflected by the fact that the DevTools front-end (and the V8
Inspector itself) performs post-processing on these async call stacks,
removing the misleading top frame from it. But this post-processing is
not applied consistently to all async stack traces (i.e. the Console
message stack traces don't get this), and potentially also not applied
consistently across consumers of the Chromium debugger backend.
Instead the V8 Inspector now removes the top frame itself and thus
reports `await` consistently with how other async tasks are reported to
debugger front-ends.
Note: This preserves backwards compatibility with old versions of
devtools-frontend, which do post-processing (for the Call Stack) only on
async stack traces marked with "async function", while we now mark these
async stack traces with "await" instead (aligned with what the front-end
is using as user visibile string anyways in the Call Stack section, and
this matching will be updated in a separate follow up CL to look for
"await" instead of "async function").
Before: https://imgur.com/kIrWcIc.png
After: https://imgur.com/HvZGqiP
Fixed: chromium:1254259
Bug: chromium:1229662
Change-Id: I57ce051a28892177b6b96221f083ae957f967e52
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3193535
Auto-Submit: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Kim-Anh Tran <kimanh@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77157}
This removes the iteration protocol from the parser entirely, and opens
up future possibilities for more bytecodes implementing the various
functions of the protocol.
Change-Id: I316b8a92434d3b5f47927408a235ddaecd65d5bb
Reviewed-on: https://chromium-review.googlesource.com/c/1403125
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58795}
New intstrumentation consists of:
- kAsyncFunctionSuspended when async function is suspended on await
(called on each await),
- kAsyncFunctionFinished when async function is finished.
Old instrumentation was based on reusing async function promise.
Using this promise produces couple side effects:
- for any promise instrumentation we first need to check if it is
special case for async function promise or not - it requires
expensive reading from promise object.
- we capture stack for async functions even if it does not contain
awaits.
- we do not properly cancel async task created for async function.
New intsrumntation resolved all these problems as well as provide
clear mapping between async task and generator which we can use later
to fetch scope information for async functions on pause.
R=dgozman@chromium.org,yangguo@chromium.org
Bug: v8:7078
Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel
Change-Id: Ifdcec947d91e6e3d4d5f9029bc080a19b8e23d41
Reviewed-on: https://chromium-review.googlesource.com/1043096
Reviewed-by: Sathya Gunasekaran <gsathya@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Commit-Queue: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53445}
Creation stack trace points to the place where callback was actually chained, scheduled points where parent promise was resolved.
For async tasks without creation stack (e.g. setTimeout) we continue to use scheduled as creation since usually they are the same.
BUG=v8:6189
R=dgozman@chromium.org
Review-Url: https://codereview.chromium.org/2868493002
Cr-Original-Commit-Position: refs/heads/master@{#45198}
Committed: e118462f18
Review-Url: https://codereview.chromium.org/2868493002
Cr-Commit-Position: refs/heads/master@{#45266}
Reason for revert:
CHECK is too strict.
Original issue's description:
> [inspector] use creation stack trace as parent for async call chains
>
> Creation stack trace points to the place where callback was actually chained, scheduled points where parent promise was resolved.
> For async tasks without creation stack (e.g. setTimeout) we continue to use scheduled as creation since usually they are the same.
>
> BUG=v8:6189
> R=dgozman@chromium.org
>
> Review-Url: https://codereview.chromium.org/2868493002
> Cr-Commit-Position: refs/heads/master@{#45198}
> Committed: e118462f18TBR=dgozman@chromium.org,alexclarke@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=v8:6189
Review-Url: https://codereview.chromium.org/2868423004
Cr-Commit-Position: refs/heads/master@{#45242}
Creation stack trace points to the place where callback was actually chained, scheduled points where parent promise was resolved.
For async tasks without creation stack (e.g. setTimeout) we continue to use scheduled as creation since usually they are the same.
BUG=v8:6189
R=dgozman@chromium.org
Review-Url: https://codereview.chromium.org/2868493002
Cr-Commit-Position: refs/heads/master@{#45198}
Add a mechanic to set these Builtin exception predictions per-Isolate
rather than per-Context in the Bootstrapper.
Also add Debugger tests which would fail without these prediction
modes set.
Does not yet test for AsyncFromSyncIteratorPrototypeReturn, as this
requires AsyncGenerators and `yield*` to be hit.
BUG=chromium:691875
R=yangguo@chromium.org, jgruber@chromium.org, gsathya@chromium.org
Change-Id: Ic2d2aba3870cce2f7321080f4278875edf253c76
Reviewed-on: https://chromium-review.googlesource.com/451967
Reviewed-by: Sathya Gunasekaran <gsathya@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Caitlin Potter <caitp@igalia.com>
Cr-Commit-Position: refs/heads/master@{#43742}
