Reorder switch clauses using newly-introduced execution counters in

src/x64/full-codegen-x64.cc

Index: src/x64/full-codegen-x64.cc
diff --git a/src/x64/full-codegen-x64.cc b/src/x64/full-codegen-x64.cc
index e03c023ff9ddfe1fb5979b67aa703f91f97936ca..f15165a781865b9f65c72a6fca917143e028a30c 100644
--- a/src/x64/full-codegen-x64.cc
+++ b/src/x64/full-codegen-x64.cc
@@ -1026,10 +1026,34 @@ void FullCodeGenerator::VisitSwitchStatement(SwitchStatement* stmt) {
 
   // Compile all the case bodies.
   for (int i = 0; i < clauses->length(); i++) {
-    Comment cmnt(masm_, "[ Case body");
     CaseClause* clause = clauses->at(i);
     __ bind(clause->body_target());
     PrepareForBailoutForId(clause->EntryId(), NO_REGISTERS);
+
+    // Initialize counter
+    { Comment cmnt(masm_, "[ Case hit counter");
+      Handle<JSGlobalPropertyCell> cell =
+          isolate()->factory()->NewJSGlobalPropertyCell(
+              Handle<Object>(Smi::FromInt(0), isolate()));
+      RecordTypeFeedbackCell(clause->CounterId(), cell);
+
+      // Increment counter
+      Label ok;
+      Operand counter = FieldOperand(rbx, JSGlobalPropertyCell::kValueOffset);
+
+      __ LoadHeapObject(rbx, cell);
+      __ movq(rcx, counter);
+      __ AssertSmi(rcx);
+      __ SmiAddConstant(rcx, rcx, Smi::FromInt(1));
+      __ j(no_overflow, &ok, Label::kNear);
+
+      // Decrement on overflow
+      __ SmiAddConstant(rcx, rcx, Smi::FromInt(-1));
+      __ bind(&ok);
+      __ movq(counter, rcx);
+    }
+
+    Comment cmnt(masm_, "[ Case body");
     VisitStatements(clause->statements());
   }