Make --always-opt also optimize top-level code.

src/hydrogen.cc

 // Copyright 2013 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/hydrogen.h"
 
 #include <sstream>
 
 #include "src/v8.h"
 
@@ skipping 4203 matching lines @@
   }
 }
 
 
 bool HOptimizedGraphBuilder::BuildGraph() {
   if (IsSubclassConstructor(current_info()->function()->kind())) {
     Bailout(kSuperReference);
     return false;
   }
 
+  if (current_info()->scope()->is_script_scope()) {
+    Bailout(kScriptContext);
+    return false;

[Toon Verwaest, 2015/04/07 20:55:05]

Doesn't this entirely disable top-level OSR?

If I'm not mistaken (didn't bisect), it seems like this is causing a large
sunspider-bitwise-and regression; 2.1 -> 8.9ms.

[Michael Starzinger, 2015/04/07 23:01:03]

It might be that this needs to be guarded by an additional "heap_slots > 0"
check, I will investigate this tomorrow. Thanks for pointing this out.

[Michael Starzinger, 2015/04/08 12:29:18]

For the record, addressed by: https://codereview.chromium.org/1063373003/

+  }
+
   Scope* scope = current_info()->scope();
   SetUpScope(scope);
 
   // Add an edge to the body entry.  This is warty: the graph's start
   // environment will be used by the Lithium translation as the initial
   // environment on graph entry, but it has now been mutated by the
   // Hydrogen translation of the instructions in the start block.  This
   // environment uses values which have not been defined yet.  These
   // Hydrogen instructions will then be replayed by the Lithium
   // translation, so they cannot have an environment effect.  The edge to
@@ skipping 7195 matching lines @@
       break;
     }
     case Variable::LOOKUP:
       return Bailout(kUnsupportedLookupSlotInDeclaration);
   }
 }
 
 
 void HOptimizedGraphBuilder::VisitModuleDeclaration(
     ModuleDeclaration* declaration) {
-  UNREACHABLE();
+  return Bailout(kModuleDeclaration);
 }
 
 
 void HOptimizedGraphBuilder::VisitImportDeclaration(
     ImportDeclaration* declaration) {
   UNREACHABLE();
 }
 
 
 void HOptimizedGraphBuilder::VisitExportDeclaration(
@@ skipping 1961 matching lines @@
   if (ShouldProduceTraceOutput()) {
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 } }  // namespace v8::internal