[coverage] Provide option to prevent triggered updates

Coverage updates are sent as deltas, and this means that it
is very important that the consumer gets /all/ updates;
otherwise, the coverage information will be wrong.

Previously, we introduces the ability into the back-end to
send triggered updates, i.e. updates that are triggered by
the back-end at interesting points in time. These updates
are delivered via an event, and any consumer must process
these events.

This CL introduces a flag to startPreciseCoverage that
controls whether the back-end is allowed to send such
triggered updates on its own initiative. The default is
`false` to maintain backwards compatibility with consumers
that don't yet handle the events.

Bug: chromium:1022031
Change-Id: Ie36a92a3b627b19ea4041f1b8da1ec66c6b9b771
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2043798
Reviewed-by: Yang Guo <yangguo@chromium.org>
Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66232}
This commit is contained in:
Sigurd Schneider 2020-02-07 15:55:19 +01:00 committed by Commit Bot
parent 04c868c1ac
commit 117520e219
3 changed files with 19 additions and 5 deletions

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@ -831,6 +831,8 @@ domain Profiler
optional boolean callCount
# Collect block-based coverage.
optional boolean detailed
# Allow the backend to send updates on its own initiative
optional boolean allowTriggeredUpdates
returns
# Monotonically increasing time (in seconds) when the coverage update was taken in the backend.
number timestamp

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@ -27,8 +27,10 @@ static const char profilerEnabled[] = "profilerEnabled";
static const char preciseCoverageStarted[] = "preciseCoverageStarted";
static const char preciseCoverageCallCount[] = "preciseCoverageCallCount";
static const char preciseCoverageDetailed[] = "preciseCoverageDetailed";
static const char preciseCoverageAllowTriggeredUpdates[] =
"preciseCoverageAllowTriggeredUpdates";
static const char typeProfileStarted[] = "typeProfileStarted";
}
} // namespace ProfilerAgentState
namespace {
@ -261,9 +263,11 @@ void V8ProfilerAgentImpl::restore() {
ProfilerAgentState::preciseCoverageCallCount, false);
bool detailed = m_state->booleanProperty(
ProfilerAgentState::preciseCoverageDetailed, false);
bool updatesAllowed = m_state->booleanProperty(
ProfilerAgentState::preciseCoverageAllowTriggeredUpdates, false);
double timestamp;
startPreciseCoverage(Maybe<bool>(callCount), Maybe<bool>(detailed),
&timestamp);
Maybe<bool>(updatesAllowed), &timestamp);
}
}
@ -294,19 +298,22 @@ Response V8ProfilerAgentImpl::stop(
return Response::OK();
}
Response V8ProfilerAgentImpl::startPreciseCoverage(Maybe<bool> callCount,
Maybe<bool> detailed,
double* out_timestamp) {
Response V8ProfilerAgentImpl::startPreciseCoverage(
Maybe<bool> callCount, Maybe<bool> detailed,
Maybe<bool> allowTriggeredUpdates, double* out_timestamp) {
if (!m_enabled) return Response::Error("Profiler is not enabled");
*out_timestamp =
v8::base::TimeTicks::HighResolutionNow().since_origin().InSecondsF();
bool callCountValue = callCount.fromMaybe(false);
bool detailedValue = detailed.fromMaybe(false);
bool allowTriggeredUpdatesValue = allowTriggeredUpdates.fromMaybe(false);
m_state->setBoolean(ProfilerAgentState::preciseCoverageStarted, true);
m_state->setBoolean(ProfilerAgentState::preciseCoverageCallCount,
callCountValue);
m_state->setBoolean(ProfilerAgentState::preciseCoverageDetailed,
detailedValue);
m_state->setBoolean(ProfilerAgentState::preciseCoverageAllowTriggeredUpdates,
allowTriggeredUpdatesValue);
// BlockCount is a superset of PreciseCount. It includes block-granularity
// coverage data if it exists (at the time of writing, that's the case for
// each function recompiled after the BlockCount mode has been set); and
@ -420,6 +427,10 @@ void V8ProfilerAgentImpl::triggerPreciseCoverageDeltaUpdate(
false)) {
return;
}
if (!m_state->booleanProperty(
ProfilerAgentState::preciseCoverageAllowTriggeredUpdates, false)) {
return;
}
v8::HandleScope handle_scope(m_isolate);
v8::debug::Coverage coverage = v8::debug::Coverage::CollectPrecise(m_isolate);
std::unique_ptr<protocol::Array<protocol::Profiler::ScriptCoverage>>

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@ -40,6 +40,7 @@ class V8ProfilerAgentImpl : public protocol::Profiler::Backend {
Response stop(std::unique_ptr<protocol::Profiler::Profile>*) override;
Response startPreciseCoverage(Maybe<bool> binary, Maybe<bool> detailed,
Maybe<bool> allow_triggered_updates,
double* out_timestamp) override;
Response stopPreciseCoverage() override;
Response takePreciseCoverage(