Make CTX allocatable by the register allocator.

runtime/vm/parser.cc

Index: runtime/vm/parser.cc
===================================================================
--- runtime/vm/parser.cc	(revision 41279)
+++ runtime/vm/parser.cc	(working copy)
@@ -127,6 +127,19 @@
 }
 
 
+LocalVariable* ParsedFunction::EnsureSavedCurrentContext() {
+  if (!has_saved_current_context_var()) {
+    LocalVariable* temp = new(I) LocalVariable(
+        function().token_pos(),
+        Symbols::SavedCurrentContextVar(),
+        Type::ZoneHandle(I, Type::DynamicType()));
+    ASSERT(temp != NULL);
+    set_saved_current_context_var(temp);
+  }
+  return saved_current_context_var();
+}
+
+
 void ParsedFunction::EnsureFinallyReturnTemp() {
   if (!has_finally_return_temp_var()) {
     LocalVariable* temp = new(I) LocalVariable(
@@ -345,6 +358,7 @@
   if (FLAG_enable_type_checks) {
     EnsureExpressionTemp();
   }
+  EnsureSavedCurrentContext();
 }
 
 
@@ -1387,7 +1401,6 @@
   ASSERT(!owner.IsNull());
   AstNode* result = NULL;
   if (owner.IsSignatureClass() && name.Equals(Symbols::Call())) {
-    EnsureSavedCurrentContext();
     result = new ClosureCallNode(token_pos, getter_call, args);
   } else {
     result = BuildClosureCall(token_pos, getter_call, args);
@@ -8549,15 +8562,7 @@
 
 
 void Parser::EnsureSavedCurrentContext() {
-  // Used later by the flow_graph_builder to save current context.
-  if (!parsed_function()->has_saved_current_context_var()) {
-    LocalVariable* temp = new(I) LocalVariable(
-        current_function().token_pos(),
-        Symbols::SavedCurrentContextVar(),
-        Type::ZoneHandle(I, Type::DynamicType()));
-    ASSERT(temp != NULL);
-    parsed_function()->set_saved_current_context_var(temp);
-  }
+  parsed_function()->EnsureSavedCurrentContext();
 }