Fix generation of context level descriptors (issue 22391).

runtime/vm/ast_printer.cc

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/ast_printer.h"
 
 #include "vm/handles.h"
 #include "vm/log.h"
 #include "vm/object.h"
 #include "vm/os.h"
@@ skipping 12 matching lines @@
   node->VisitChildren(this);
   ISL_Print(")");
 }
 
 
 void AstPrinter::VisitSequenceNode(SequenceNode* node) {
   indent_++;
   LocalScope* scope = node->scope();
   ISL_Print("(%s (scope \"%p\"", node->PrettyName(), scope);
   if (scope != NULL) {
-    ISL_Print(" loop %d", scope->loop_level());
+    ISL_Print(" (%d-%d) loop %d",
+              scope->begin_token_pos(),
+              scope->end_token_pos(),
+              scope->loop_level());
     if (scope->HasContextLevel()) {
       ISL_Print(" context %d captures %d",
                 scope->context_level(),
                 scope->num_context_variables());
     } else {
       ASSERT(scope->num_context_variables() == 0);
     }
   }
   ISL_Print(")");
   for (int i = 0; i < node->length(); ++i) {
@@ skipping 515 matching lines @@
   ASSERT(node_sequence != NULL);
   AstPrinter ast_printer;
   const char* function_name =
       parsed_function.function().ToFullyQualifiedCString();
   ISL_Print("Ast for function '%s' {\n", function_name);
   node_sequence->Visit(&ast_printer);
   ISL_Print("}\n");
 }
 
 }  // namespace dart