Support for precise stepping in functions compiled before debugging was started (step 1)

src/runtime.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 8090 matching lines @@
   // All done. Return the compiled code.
   ASSERT(function->is_compiled());
   return function->code();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_LazyRecompile) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);
   Handle<JSFunction> function = args.at<JSFunction>(0);
+
+  // If the function is not compiled ignore the lazy
+  // recompilation. This can happen if the debugger is activated and
+  // the function is returned to the not compiled state.
+  if (!function->shared()->is_compiled()) {
+    function->ReplaceCode(function->shared()->code());
+    return function->code();
+  }
+
   // If the function is not optimizable or debugger is active continue using the
   // code from the full compiler.
   if (!function->shared()->code()->optimizable() ||
       isolate->DebuggerHasBreakPoints()) {
     if (FLAG_trace_opt) {
       PrintF("[failed to optimize ");
       function->PrintName();
       PrintF(": is code optimizable: %s, is debugger enabled: %s]\n",
           function->shared()->code()->optimizable() ? "T" : "F",
           isolate->DebuggerHasBreakPoints() ? "T" : "F");
@@ skipping 4978 matching lines @@
   } else {
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     isolate->counters()->gc_last_resort_from_js()->Increment();
     isolate->heap()->CollectAllGarbage(false);
   }
 }
 
 
 } }  // namespace v8::internal