Fix bug in Runtime_CompileOptimized resulting from stack overflow.

src/runtime/runtime-compiler.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/arguments.h"
 #include "src/compiler.h"
 #include "src/deoptimizer.h"
 #include "src/frames.h"
@@ skipping 51 matching lines @@
              isolate->DebuggerHasBreakPoints() ? "T" : "F");
     }
     function->ReplaceCode(*unoptimized);
     return function->code();
   }
 
   Compiler::ConcurrencyMode mode =
       concurrent ? Compiler::CONCURRENT : Compiler::NOT_CONCURRENT;
   Handle<Code> code;
   if (Compiler::GetOptimizedCode(function, unoptimized, mode).ToHandle(&code)) {
+    // Optimization succeeded, return optimized code.
     function->ReplaceCode(*code);
   } else {
-    function->ReplaceCode(function->shared()->code());
+    // Optimization failed, get unoptimized code.
+    if (isolate->has_pending_exception()) {  // Possible stack overflow.
+      return isolate->heap()->exception();
+    }
+    code = Handle<Code>(function->shared()->code(), isolate);
+    if (code->kind() != Code::FUNCTION &&
+        code->kind() != Code::OPTIMIZED_FUNCTION) {
+      ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+          isolate, code, Compiler::GetUnoptimizedCode(function));
+    }
+    function->ReplaceCode(*code);
   }
 
   DCHECK(function->code()->kind() == Code::FUNCTION ||
          function->code()->kind() == Code::OPTIMIZED_FUNCTION ||
          function->IsInOptimizationQueue());
   return function->code();
 }
 
 
 RUNTIME_FUNCTION(Runtime_NotifyStubFailure) {
@@ skipping 357 matching lines @@
   DCHECK(args.smi_at(4) == SLOPPY || args.smi_at(4) == STRICT);
   StrictMode strict_mode = static_cast<StrictMode>(args.smi_at(4));
   DCHECK(args[5]->IsSmi());
   Handle<SharedFunctionInfo> outer_info(args.at<JSFunction>(2)->shared(),
                                         isolate);
   return CompileGlobalEval(isolate, args.at<String>(1), outer_info,
                            args.at<Object>(3), strict_mode, args.smi_at(5));
 }
 }
 }  // namespace v8::internal