VM: Only update hash table stats when needed for printing.

runtime/vm/hash_table.h

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef RUNTIME_VM_HASH_TABLE_H_
 #define RUNTIME_VM_HASH_TABLE_H_
 
 #include "platform/assert.h"
 #include "vm/object.h"
 
@@ skipping 269 matching lines @@
   intptr_t NumGrows() const { return GetSmiValueAt(kNumGrowsIndex); }
   intptr_t NumLT5Collisions() const {
     return GetSmiValueAt(kNumLT5LookupsIndex);
   }
   intptr_t NumLT25Collisions() const {
     return GetSmiValueAt(kNumLT25LookupsIndex);
   }
   intptr_t NumGT25Collisions() const {
     return GetSmiValueAt(kNumGT25LookupsIndex);
   }
-  void UpdateGrowth() const { AdjustSmiValueAt(kNumGrowsIndex, 1); }
+  void UpdateGrowth() const {
+    if (KeyTraits::ReportStats()) {
+      AdjustSmiValueAt(kNumGrowsIndex, 1);
+    }
+  }
   void UpdateCollisions(intptr_t collisions) const {
-    if (data_->raw()->IsVMHeapObject()) {
-      return;
-    }
-    if (collisions < 5) {
-      AdjustSmiValueAt(kNumLT5LookupsIndex, 1);
-    } else if (collisions < 25) {
-      AdjustSmiValueAt(kNumLT25LookupsIndex, 1);
-    } else {
-      AdjustSmiValueAt(kNumGT25LookupsIndex, 1);
+    if (KeyTraits::ReportStats()) {
+      if (data_->raw()->IsVMHeapObject()) {
+        return;
+      }
+      if (collisions < 5) {
+        AdjustSmiValueAt(kNumLT5LookupsIndex, 1);
+      } else if (collisions < 25) {
+        AdjustSmiValueAt(kNumLT25LookupsIndex, 1);
+      } else {
+        AdjustSmiValueAt(kNumGT25LookupsIndex, 1);
+      }
     }
   }
   void PrintStats() const {
     if (!KeyTraits::ReportStats()) {
       return;
     }
     // clang-format off
     OS::Print("Stats for %s table :\n"
               " Size of table = %" Pd ",Number of Occupied entries = %" Pd "\n"
               " Number of Grows = %" Pd "\n"
@@ skipping 371 matching lines @@
     ASSERT(data != Array::null());
   }
   UnorderedHashSet(Zone* zone, RawArray* data) : BaseSet(zone, data) {}
   UnorderedHashSet(Object* key, Smi* value, Array* data)
       : BaseSet(key, value, data) {}
 };
 
 }  // namespace dart
 
 #endif  // RUNTIME_VM_HASH_TABLE_H_