[heap] Introduce enum of garbage collection reasons.

test/unittests/heap/gc-tracer-unittest.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <cmath>
 #include <limits>
 
 #include "src/globals.h"
 #include "src/heap/gc-tracer.h"
 #include "src/isolate.h"
@@ skipping 142 matching lines @@
   EXPECT_EQ((counter3 - counter1) / (time3 - time1), throughput);
 }
 
 TEST_F(GCTracerTest, RegularScope) {
   GCTracer* tracer = i_isolate()->heap()->tracer();
   tracer->ResetForTesting();
 
   EXPECT_DOUBLE_EQ(0.0, tracer->current_.scopes[GCTracer::Scope::MC_MARK]);
   // Sample not added because it's not within a started tracer.
   tracer->AddScopeSample(GCTracer::Scope::MC_MARK, 100);
-  tracer->Start(MARK_COMPACTOR, "gc unittest", "collector unittest");
+  tracer->Start(MARK_COMPACTOR, GarbageCollectionReason::kTesting,
+                "collector unittest");
   tracer->AddScopeSample(GCTracer::Scope::MC_MARK, 100);
   tracer->Stop(MARK_COMPACTOR);
   EXPECT_DOUBLE_EQ(100.0, tracer->current_.scopes[GCTracer::Scope::MC_MARK]);
 }
 
 TEST_F(GCTracerTest, IncrementalScope) {
   GCTracer* tracer = i_isolate()->heap()->tracer();
   tracer->ResetForTesting();
 
   EXPECT_DOUBLE_EQ(
       0.0, tracer->current_.scopes[GCTracer::Scope::MC_INCREMENTAL_FINALIZE]);
   // Sample is added because its ScopeId is listed as incremental sample.
   tracer->AddScopeSample(GCTracer::Scope::MC_INCREMENTAL_FINALIZE, 100);
-  tracer->Start(MARK_COMPACTOR, "gc unittest", "collector unittest");
+  tracer->Start(MARK_COMPACTOR, GarbageCollectionReason::kTesting,
+                "collector unittest");
   // Switch to incremental MC to enable writing back incremental scopes.
   tracer->current_.type = GCTracer::Event::INCREMENTAL_MARK_COMPACTOR;
   tracer->AddScopeSample(GCTracer::Scope::MC_INCREMENTAL_FINALIZE, 100);
   tracer->Stop(MARK_COMPACTOR);
   EXPECT_DOUBLE_EQ(
       200.0, tracer->current_.scopes[GCTracer::Scope::MC_INCREMENTAL_FINALIZE]);
 }
 
 TEST_F(GCTracerTest, IncrementalMarkingDetails) {
   GCTracer* tracer = i_isolate()->heap()->tracer();
   tracer->ResetForTesting();
 
   // Round 1.
   tracer->AddScopeSample(GCTracer::Scope::MC_INCREMENTAL_FINALIZE, 50);
-  tracer->Start(MARK_COMPACTOR, "gc unittest", "collector unittest");
+  tracer->Start(MARK_COMPACTOR, GarbageCollectionReason::kTesting,
+                "collector unittest");
   // Switch to incremental MC to enable writing back incremental scopes.
   tracer->current_.type = GCTracer::Event::INCREMENTAL_MARK_COMPACTOR;
   tracer->AddScopeSample(GCTracer::Scope::MC_INCREMENTAL_FINALIZE, 100);
   tracer->Stop(MARK_COMPACTOR);
   EXPECT_DOUBLE_EQ(
       100,
       tracer->current_
           .incremental_marking_scopes[GCTracer::Scope::MC_INCREMENTAL_FINALIZE]
           .longest_step);
   EXPECT_EQ(
       2,
       tracer->current_
           .incremental_marking_scopes[GCTracer::Scope::MC_INCREMENTAL_FINALIZE]
           .steps);
   EXPECT_DOUBLE_EQ(
       150,
       tracer->current_
           .incremental_marking_scopes[GCTracer::Scope::MC_INCREMENTAL_FINALIZE]
           .cumulative_duration);
 
   // Round 2. Cumulative numbers should add up, others should be reset.
   tracer->AddScopeSample(GCTracer::Scope::MC_INCREMENTAL_FINALIZE, 13);
   tracer->AddScopeSample(GCTracer::Scope::MC_INCREMENTAL_FINALIZE, 15);
-  tracer->Start(MARK_COMPACTOR, "gc unittest", "collector unittest");
+  tracer->Start(MARK_COMPACTOR, GarbageCollectionReason::kTesting,
+                "collector unittest");
   // Switch to incremental MC to enable writing back incremental scopes.
   tracer->current_.type = GCTracer::Event::INCREMENTAL_MARK_COMPACTOR;
   tracer->AddScopeSample(GCTracer::Scope::MC_INCREMENTAL_FINALIZE, 122);
   tracer->Stop(MARK_COMPACTOR);
   EXPECT_DOUBLE_EQ(
       122,
       tracer->current_
           .incremental_marking_scopes[GCTracer::Scope::MC_INCREMENTAL_FINALIZE]
           .longest_step);
   EXPECT_EQ(
       3,
       tracer->current_
           .incremental_marking_scopes[GCTracer::Scope::MC_INCREMENTAL_FINALIZE]
           .steps);
   EXPECT_DOUBLE_EQ(
       300,
       tracer->current_
           .incremental_marking_scopes[GCTracer::Scope::MC_INCREMENTAL_FINALIZE]
           .cumulative_duration);
 }
 
 }  // namespace internal
 }  // namespace v8