[strong] Introduce --use-strong flag

src/compiler.cc

 // Copyright 2012 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/compiler.h"
 
 #include "src/ast-numbering.h"
 #include "src/ast-this-access-visitor.h"
@@ skipping 1340 matching lines @@
     } else {
       info.MarkAsGlobal();
     }
     info.SetCachedData(cached_data, compile_options);
     info.SetExtension(extension);
     info.SetContext(context);
     if (FLAG_serialize_toplevel &&
         compile_options == ScriptCompiler::kProduceCodeCache) {
       info.PrepareForSerializing();
     }
-    if (FLAG_use_strict) {
-      info.SetLanguageMode(
-          static_cast<LanguageMode>(info.language_mode() | STRICT_BIT));
-    }
+
+    LanguageMode language_mode =
+        construct_language_mode(FLAG_use_strict, FLAG_use_strong);
+    info.SetLanguageMode(
+        static_cast<LanguageMode>(info.language_mode() | language_mode));
 
     result = CompileToplevel(&info);
     if (extension == NULL && !result.is_null() && !result->dont_cache()) {
       compilation_cache->PutScript(source, context, result);
       if (FLAG_serialize_toplevel &&
           compile_options == ScriptCompiler::kProduceCodeCache) {
         HistogramTimerScope histogram_timer(
             isolate->counters()->compile_serialize());
         *cached_data = CodeSerializer::Serialize(isolate, result, source);
         if (FLAG_profile_deserialization) {
@@ skipping 10 matching lines @@
   return result;
 }
 
 
 Handle<SharedFunctionInfo> Compiler::CompileStreamedScript(
     CompilationInfo* info, int source_length) {
   Isolate* isolate = info->isolate();
   isolate->counters()->total_load_size()->Increment(source_length);
   isolate->counters()->total_compile_size()->Increment(source_length);
 
-  if (FLAG_use_strict) {
-    info->SetLanguageMode(
-        static_cast<LanguageMode>(info->language_mode() | STRICT_BIT));
-  }
+  LanguageMode language_mode =
+      construct_language_mode(FLAG_use_strict, FLAG_use_strong);
+  info->SetLanguageMode(
+      static_cast<LanguageMode>(info->language_mode() | language_mode));
+
   // TODO(marja): FLAG_serialize_toplevel is not honoured and won't be; when the
   // real code caching lands, streaming needs to be adapted to use it.
   return CompileToplevel(info);
 }
 
 
 Handle<SharedFunctionInfo> Compiler::BuildFunctionInfo(
     FunctionLiteral* literal, Handle<Script> script,
     CompilationInfo* outer_info) {
   // Precondition: code has been parsed and scopes have been analyzed.
@@ skipping 205 matching lines @@
 }
 
 
 #if DEBUG
 void CompilationInfo::PrintAstForTesting() {
   PrintF("--- Source from AST ---\n%s\n",
          PrettyPrinter(isolate(), zone()).PrintProgram(function()));
 }
 #endif
 } }  // namespace v8::internal