Introduce code flushing of RegExp code.

src/jsregexp.cc

 // Copyright 2006-2009 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 277 matching lines @@
 // from the source pattern.
 // If compilation fails, an exception is thrown and this function
 // returns false.
 bool RegExpImpl::EnsureCompiledIrregexp(Handle<JSRegExp> re, bool is_ascii) {
   Object* compiled_code = re->DataAt(JSRegExp::code_index(is_ascii));
 #ifdef V8_INTERPRETED_REGEXP
   if (compiled_code->IsByteArray()) return true;
 #else  // V8_INTERPRETED_REGEXP (RegExp native code)
   if (compiled_code->IsCode()) return true;
 #endif
+  // We could potentially have marked this as flushable, but have keept

[Erik Corry, 2011/06/30 18:48:25]

keept -> kept

[Rico, 2011/07/01 05:58:09]

Done.

+  // a saved version if we did not flush it yet.
+  Object* saved_code = re->DataAt(JSRegExp::saved_code_index(is_ascii));
+  if (saved_code->IsCode()) {
+    // Reinstate the code in the original place.
+    re->SetDataAt(JSRegExp::code_index(is_ascii), saved_code);
+    ASSERT(compiled_code->IsSmi());
+    return true;
+  }
   return CompileIrregexp(re, is_ascii);
 }
 
 
 bool RegExpImpl::CompileIrregexp(Handle<JSRegExp> re, bool is_ascii) {
   // Compile the RegExp.
   Isolate* isolate = re->GetIsolate();
   ZoneScope zone_scope(isolate, DELETE_ON_EXIT);
   PostponeInterruptsScope postpone(isolate);
   Object* entry = re->DataAt(JSRegExp::code_index(is_ascii));
   if (entry->IsJSObject()) {
     // If it's a JSObject, a previous compilation failed and threw this object.
     // Re-throw the object without trying again.
     isolate->Throw(entry);
     return false;
   }
-  ASSERT(entry->IsTheHole());
+  ASSERT(entry->IsSmi());
 
   JSRegExp::Flags flags = re->GetFlags();
 
   Handle<String> pattern(re->Pattern());
   if (!pattern->IsFlat()) {
     FlattenString(pattern);
   }
 
   RegExpCompileData compile_data;
   FlatStringReader reader(isolate, pattern);
@@ skipping 5006 matching lines @@
   }
 
   return compiler.Assemble(&macro_assembler,
                            node,
                            data->capture_count,
                            pattern);
 }
 
 
 }}  // namespace v8::internal