PATCH (not to be comitted): Support for printing instruction statistics

runtime/vm/clustered_snapshot.cc

 // Copyright (c) 2016, 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.
 
 #include "vm/clustered_snapshot.h"
 
 #include "platform/assert.h"
 #include "vm/bootstrap.h"
 #include "vm/class_finalizer.h"
 #include "vm/dart.h"
 #include "vm/dart_entry.h"
 #include "vm/exceptions.h"
 #include "vm/heap.h"
 #include "vm/lockers.h"
 #include "vm/longjump.h"
 #include "vm/native_entry.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
 #include "vm/stub_code.h"
 #include "vm/symbols.h"
 #include "vm/timeline.h"
 #include "vm/version.h"
 
 namespace dart {
 
+DEFINE_FLAG(bool, print_instruction_stats, false,
+            "Print instruction statistics");
+
 static RawObject* AllocateUninitialized(PageSpace* old_space, intptr_t size) {
   ASSERT(Utils::IsAligned(size, kObjectAlignment));
   uword address =
       old_space->TryAllocateDataBumpLocked(size, PageSpace::kForceGrowth);
   if (address == 0) {
     OUT_OF_MEMORY();
   }
   return reinterpret_cast<RawObject*>(address + kHeapObjectTag);
 }
 
@@ skipping 5289 matching lines @@
       OS::Print("Instructions(CodeSize): %" Pd "\n",
                 instructions_writer_->text_size());
     }
     total_size +=
         instructions_writer_->data_size() + instructions_writer_->text_size();
   }
 
   if (FLAG_print_snapshot_sizes) {
     OS::Print("Total(CodeSize): %" Pd "\n", total_size);
   }
+
+  if (FLAG_print_instruction_stats) {
+    instructions_writer_->DumpCombinedCodeStatistics();
+  }
 }
 
 
 RawApiError* IsolateSnapshotReader::ReadFullSnapshot() {
   Deserializer deserializer(thread_, kind_, buffer_, size_,
                             instructions_buffer_, data_buffer_);
 
   RawApiError* error = deserializer.VerifyVersionAndFeatures();
   if (error != ApiError::null()) {
     return error;
@@ skipping 16 matching lines @@
 
   deserializer.ReadVMSnapshot();
 
   Dart::set_instructions_snapshot_buffer(instructions_buffer_);
   Dart::set_data_snapshot_buffer(data_buffer_);
 
   return ApiError::null();
 }
 
 }  // namespace dart