VM: Reduce the number of edge counters in generated code.

runtime/vm/intermediate_language_mips.cc

Index: runtime/vm/intermediate_language_mips.cc
===================================================================
--- runtime/vm/intermediate_language_mips.cc	(revision 37078)
+++ runtime/vm/intermediate_language_mips.cc	(working copy)
@@ -8,6 +8,7 @@
 #include "vm/intermediate_language.h"
 
 #include "vm/dart_entry.h"
+#include "vm/flow_graph.h"
 #include "vm/flow_graph_compiler.h"
 #include "vm/locations.h"
 #include "vm/object_store.h"
@@ -4498,7 +4499,9 @@
 void TargetEntryInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   __ Bind(compiler->GetJumpLabel(this));
   if (!compiler->is_optimizing()) {
-    if (FLAG_emit_edge_counters) {
+    if (FLAG_emit_edge_counters &&
+        (!last_instruction()->IsGoto() ||

[Cutch, 2014/06/06 14:56:12]

Maybe add a comment here:

// Emit an edge counter when the block does not end in a GoTo or
// when this is not an exception catch block entry into the graph.
bool should_emit_edge_counter = !last_instruction()->IsGoto() ||
    (this == compiler->flow_graph().graph_entry()->normal_entry());

if (FLAG_emit_edge_counters && should_emit_edge_counter) {
...

[Florian Schneider, 2014/06/10 08:56:39]

Done.

+         (this == compiler->flow_graph().graph_entry()->normal_entry()))) {
       compiler->EmitEdgeCounter();
     }
     // On MIPS the deoptimization descriptor points after the edge counter