[turbofan] Add DebugBreak machine operator and support

src/compiler/machine-operator.cc

Index: src/compiler/machine-operator.cc
diff --git a/src/compiler/machine-operator.cc b/src/compiler/machine-operator.cc
index 0d229c7abe110252e092dc4cc343fcac180dd048..1b0b7e54322b696cbadce63f6800a606d5790301 100644
--- a/src/compiler/machine-operator.cc
+++ b/src/compiler/machine-operator.cc
@@ -526,6 +526,13 @@ struct MachineOperatorGlobalCache {
   AtomicStore##Type##Operator kAtomicStore##Type;
   ATOMIC_REPRESENTATION_LIST(ATOMIC_STORE)
 #undef STORE
+
+  struct DebugBreakOperator : public Operator {
+    DebugBreakOperator()
+        : Operator(IrOpcode::kDebugBreak, Operator::kNoThrow, "DebugBreak", 0,
+                   1, 1, 0, 1, 0) {}

[Michael Starzinger, 2016/05/19 08:53:23]

I assume the effect inputs are there in the hope of constraining it in the
effect chain. For now this operator is only used in scheduled graph. Would you
be fine with making this a "pure" operator for now instead (i.e. just adding it
to PURE_OP_LIST). Constraining it in the effect chain would require further
testing.

[danno, 2016/05/19 09:05:04]

Done.

+  };
+  DebugBreakOperator kDebugBreak;
 };
 
 
@@ -604,6 +611,9 @@ const Operator* MachineOperatorBuilder::Store(StoreRepresentation store_rep) {
   return nullptr;
 }
 
+const Operator* MachineOperatorBuilder::DebugBreak() {
+  return &cache_.kDebugBreak;
+}
 
 const Operator* MachineOperatorBuilder::CheckedLoad(
     CheckedLoadRepresentation rep) {