[turbofan] Introduce lazy bailout, masked as a call.

src/compiler/ast-graph-builder.cc

Index: src/compiler/ast-graph-builder.cc
diff --git a/src/compiler/ast-graph-builder.cc b/src/compiler/ast-graph-builder.cc
index 6ce9269927c645fd16b8f6b431606bcd8101f570..34167274745b670ea6f4481b4fea69dd9aee19d9 100644
--- a/src/compiler/ast-graph-builder.cc
+++ b/src/compiler/ast-graph-builder.cc
@@ -1410,10 +1410,10 @@ void AstGraphBuilder::VisitTryCatchStatement(TryCatchStatement* stmt) {
   }
   try_control.EndTry();
 
-  // TODO(mstarzinger): We are only using a runtime call to get a lazy bailout

[Michael Starzinger, 2015/10/16 13:25:07]

Can we leave the TODO in place? In the long run I would still like to do this
without re-entering deoptimized code. You could even reference issue v8:4195,
which is tracking this.

-  // point, there is no need to really emit an actual call. Optimize this!
-  Node* guard = NewNode(javascript()->CallRuntime(Runtime::kMaxSmi, 0));
-  PrepareFrameState(guard, stmt->HandlerId());
+  // Insert lazy bailout point.
+  NewNode(common()->Call(Linkage::GetLazyBailoutDescriptor(graph_zone())),
+          jsgraph()->ZeroConstant(),                      // dummy target.
+          environment()->Checkpoint(stmt->HandlerId()));  // frame state.
 
   // Clear message object as we enter the catch block.
   Node* the_hole = jsgraph()->TheHoleConstant();