[Interpreter] Add dispatch counters for each bytecode.

src/d8.cc

Index: src/d8.cc
diff --git a/src/d8.cc b/src/d8.cc
index c23c1a4a9c722f0839fd4ca4976c41e90b10cda0..d9c9a5d0ae54fe2ea3cbff11b45accfd0d894688 100644
--- a/src/d8.cc
+++ b/src/d8.cc
@@ -12,6 +12,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <sys/stat.h>
+#include <fstream>
 
 #ifdef V8_SHARED
 #include <assert.h>
@@ -41,6 +42,7 @@
 #include "src/base/platform/platform.h"
 #include "src/base/sys-info.h"
 #include "src/basic-block-profiler.h"
+#include "src/interpreter/interpreter.h"
 #include "src/snapshot/natives.h"
 #include "src/utils.h"
 #include "src/v8.h"
@@ -1275,6 +1277,25 @@ struct CounterAndKey {
 inline bool operator<(const CounterAndKey& lhs, const CounterAndKey& rhs) {
   return strcmp(lhs.key, rhs.key) < 0;
 }
+
+void Shell::WriteInterpreterDispatchCounters(Isolate* isolate) {
+  std::ofstream stream(i::FLAG_trace_ignition_dispatches_output_file);
+
+  uintptr_t* handler_dispatch_counters = reinterpret_cast<i::Isolate*>(isolate)
+                                             ->interpreter()
+                                             ->dispatch_counters();
+  stream << '{';
+  for (int counter_index = 0;
+       counter_index <= static_cast<int>(i::interpreter::Bytecode::kLast);
+       ++counter_index) {
+    if (counter_index > 0) stream << ", ";
+    i::interpreter::Bytecode bytecode =
+        i::interpreter::Bytecodes::FromByte(counter_index);
+    stream << '\"' << i::interpreter::Bytecodes::ToString(bytecode)
+           << "\": " << handler_dispatch_counters[counter_index];
+  }
+  stream << '}';
+}
 #endif  // !V8_SHARED
 
 
@@ -1312,6 +1333,11 @@ void Shell::OnExit(v8::Isolate* isolate) {
            "-------------+\n");
     delete [] counters;
   }
+
+  if (i::FLAG_trace_ignition_dispatches) {
+    WriteInterpreterDispatchCounters(isolate);
+  }
+
   delete counters_file_;
   delete counter_map_;
 #endif  // !V8_SHARED