[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 d7e1b6ab06e6fa67638dd74f89434b5c78f6b404..a107afa3216d8a384ee3d7229cc86a2b17f87c13 100644
--- a/src/d8.cc
+++ b/src/d8.cc
@@ -9,6 +9,7 @@
 #endif
 
 #include <errno.h>
+#include <inttypes.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/stat.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"
@@ -1304,6 +1306,21 @@ inline bool operator<(const CounterAndKey& lhs, const CounterAndKey& rhs) {
 }
 #endif  // !V8_SHARED
 
+void Shell::DumpHandlersDispatchCounters(FILE* stream, Isolate* isolate) {

[rmcilroy, 2016/04/05 10:00:45]

WriteInterpreterDispatchCounters

[Stefano Sanfilippo, 2016/04/05 14:01:45]

Done.

+  uint32_t* handler_dispatch_counters = reinterpret_cast<i::Isolate*>(isolate)
+                                            ->interpreter()
+                                            ->handlers_dispatch_counters();
+
+  fputc('{', stream);

[rmcilroy, 2016/04/05 10:00:45]

Can we just use an ostream instead of the c file output?

[Stefano Sanfilippo, 2016/04/05 14:01:45]

Done.

+  for (int i = 0; i < i::interpreter::Interpreter::kCountersTableRowSize; ++i) {
+    if (i > 0) fputs(", ", stream);
+    i::interpreter::Bytecode bytecode = i::interpreter::Bytecodes::FromByte(i);
+    fprintf(stream, "\"%s\": %" PRIu32,
+            i::interpreter::Bytecodes::ToString(bytecode),
+            handler_dispatch_counters[i]);
+  }
+  fputc('}', stream);
+}
 
 void Shell::OnExit(v8::Isolate* isolate) {
 #ifndef V8_SHARED
@@ -1339,6 +1356,15 @@ void Shell::OnExit(v8::Isolate* isolate) {
            "-------------+\n");
     delete [] counters;
   }
+
+  if (i::FLAG_ignition_count_handler_dispatches) {
+    FILE* ignition_counters_stream =
+        fopen(i::FLAG_ignition_handler_to_handler_output_file, "w");

[rmcilroy, 2016/04/05 10:00:45]

nit - just do the open / close in WriteInterpreterDispatchCounters

[Stefano Sanfilippo, 2016/04/05 14:01:45]

I'd rather open the stream externally and pass it to the function, since in the
followup we will be serializing both tables to the same file.

+    CHECK_NOT_NULL(ignition_counters_stream);
+    DumpHandlersDispatchCounters(ignition_counters_stream, isolate);
+    fclose(ignition_counters_stream);
+  }
+
   delete counters_file_;
   delete counter_map_;
 #endif  // !V8_SHARED