[wasm] Sample EH event count at each event

The main thread isolate may live until the end of the process, in which
case we would not record the counts. Sample at each event instead.

R=ahaas@chromium.org

Bug: v8:8091
Change-Id: I5b1eb023e4ca5410c7d8f4212ff20410044bf4f2
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2710433
Commit-Queue: Thibaud Michaud <thibaudm@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72947}

src/logging/counters-definitions.h

@@ -91,8 +91,6 @@ namespace internal {
   HR(wasm_rethrow_count, V8.WasmReThrowCount, 0, 100000, 30)                   \
   /* number of caught exceptions per isolate */                                \
   HR(wasm_catch_count, V8.WasmCatchCount, 0, 100000, 30)                       \
-  /* number of uncaught exceptions per isolate */                              \
-  HR(wasm_uncaught_count, V8.WasmUncaughtCount, 0, 100000, 30)                 \
   /* Ticks observed in a single Turbofan compilation, in 1K */                 \
   HR(turbofan_ticks, V8.TurboFan1KTicks, 0, 100000, 200)                       \
   /* Backtracks observed in a single regexp interpreter execution */           \

src/wasm/wasm-engine.cc

@@ -1016,11 +1016,6 @@ void WasmEngine::RemoveIsolate(Isolate* isolate) {
     info->code_to_log.clear();
   }
   DCHECK(info->code_to_log.empty());
-  isolate->counters()->wasm_throw_count()->AddSample(info->throw_count);
-  isolate->counters()->wasm_rethrow_count()->AddSample(info->rethrow_count);
-  isolate->counters()->wasm_catch_count()->AddSample(info->catch_count);
-  isolate->counters()->wasm_uncaught_count()->AddSample(
-      info->throw_count + info->rethrow_count - info->catch_count);
 }
 
 void WasmEngine::LogCode(Vector<WasmCode*> code_vec) {
@@ -1403,31 +1398,37 @@ void SampleExceptionEvent(base::ElapsedTimer* timer, TimedHistogram* counter) {
 
 void WasmEngine::SampleThrowEvent(Isolate* isolate) {
   base::MutexGuard guard(&mutex_);
-  int& throw_count = isolates_[isolate]->throw_count;
+  IsolateInfo* isolate_info = isolates_[isolate].get();
+  int& throw_count = isolate_info->throw_count;
   // To avoid an int overflow, clip the count to the histogram's max value.
   throw_count =
       std::min(throw_count + 1, isolate->counters()->wasm_throw_count()->max());
-  SampleExceptionEvent(&isolates_[isolate]->throw_timer,
+  isolate->counters()->wasm_throw_count()->AddSample(throw_count);
+  SampleExceptionEvent(&isolate_info->throw_timer,
                        isolate->counters()->wasm_time_between_throws());
 }
 
 void WasmEngine::SampleRethrowEvent(Isolate* isolate) {
   base::MutexGuard guard(&mutex_);
-  int& rethrow_count = isolates_[isolate]->rethrow_count;
+  IsolateInfo* isolate_info = isolates_[isolate].get();
+  int& rethrow_count = isolate_info->rethrow_count;
   // To avoid an int overflow, clip the count to the histogram's max value.
   rethrow_count = std::min(rethrow_count + 1,
                            isolate->counters()->wasm_rethrow_count()->max());
-  SampleExceptionEvent(&isolates_[isolate]->rethrow_timer,
+  isolate->counters()->wasm_rethrow_count()->AddSample(rethrow_count);
+  SampleExceptionEvent(&isolate_info->rethrow_timer,
                        isolate->counters()->wasm_time_between_rethrows());
 }
 
 void WasmEngine::SampleCatchEvent(Isolate* isolate) {
   base::MutexGuard guard(&mutex_);
-  int& catch_count = isolates_[isolate]->catch_count;
+  IsolateInfo* isolate_info = isolates_[isolate].get();
+  int& catch_count = isolate_info->catch_count;
   // To avoid an int overflow, clip the count to the histogram's max value.
   catch_count =
       std::min(catch_count + 1, isolate->counters()->wasm_catch_count()->max());
-  SampleExceptionEvent(&isolates_[isolate]->catch_timer,
+  isolate->counters()->wasm_catch_count()->AddSample(catch_count);
+  SampleExceptionEvent(&isolate_info->catch_timer,
                        isolate->counters()->wasm_time_between_catch());
 }