Fix code invalidation of functions with references to deferred libraries

runtime/vm/object.cc

 // Copyright (c) 2012, 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/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/cpu.h"
@@ skipping 2496 matching lines @@
         continue;
       }
 
       function ^= code.function();
       // If function uses dependent code switch it to unoptimized.
       if (code.is_optimized() && (function.CurrentCode() == code.raw())) {
         ReportSwitchingCode(code);
         function.SwitchToUnoptimizedCode();
       } else if (function.unoptimized_code() == code.raw()) {
         ReportSwitchingCode(code);
+        // Remove the code object from the function. The next time the
+        // function is invoked, it will be compiled again.
         function.ClearCode();
+        // Invalidate the old code object so existing references to it
+        // (from optimized code) will fail when invoked.
+        if (!CodePatcher::IsEntryPatched(code)) {
+          CodePatcher::PatchEntry(code);
+        }
       }
     }
   }
 
  private:
   const Array& array_;
   DISALLOW_COPY_AND_ASSIGN(WeakCodeReferences);
 };
 
 
@@ skipping 7024 matching lines @@
   virtual void ReportDeoptimization(const Code& code) {
     // This gets called when the code object is on the stack
     // while nuking code that depends on a prefix. We don't expect
     // this to happen, so make sure we die loudly if we find
     // ourselves here.
     UNIMPLEMENTED();
   }
 
   virtual void ReportSwitchingCode(const Code& code) {
     if (FLAG_trace_deoptimization || FLAG_trace_deoptimization_verbose) {
-      OS::PrintErr("Prefix '%s': deleting %s code for function '%s'\n",
+      OS::PrintErr("Prefix '%s': deleting %s code for %s function '%s'\n",
         String::Handle(prefix_.name()).ToCString(),
         code.is_optimized() ? "optimized" : "unoptimized",
+        CodePatcher::IsEntryPatched(code) ? "patched" : "unpatched",
         Function::Handle(code.function()).ToCString());
     }
   }
 
  private:
   const LibraryPrefix& prefix_;
   DISALLOW_COPY_AND_ASSIGN(PrefixDependentArray);
 };
 
 
@@ skipping 9271 matching lines @@
   return tag_label.ToCString();
 }
 
 
 void UserTag::PrintJSONImpl(JSONStream* stream, bool ref) const {
   Instance::PrintJSONImpl(stream, ref);
 }
 
 
 }  // namespace dart