Refactor Heap::SymbolMapForString to use switch/case.

src/heap.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 3957 matching lines @@
   }
   return result;
 }
 
 
 Map* Heap::SymbolMapForString(String* string) {
   // If the string is in new space it cannot be used as a symbol.
   if (InNewSpace(string)) return NULL;
 
   // Find the corresponding symbol map for strings.
-  Map* map = string->map();
-  if (map == ascii_string_map()) {
-    return ascii_symbol_map();
+  switch (string->map()->instance_type()) {
+    case STRING_TYPE: return symbol_map();
+    case ASCII_STRING_TYPE: return ascii_symbol_map();
+    case CONS_STRING_TYPE: return cons_symbol_map();
+    case CONS_ASCII_STRING_TYPE: return cons_ascii_symbol_map();
+    case EXTERNAL_STRING_TYPE: return external_symbol_map();
+    case EXTERNAL_ASCII_STRING_TYPE: return external_ascii_symbol_map();
+    case EXTERNAL_STRING_WITH_ASCII_DATA_TYPE:
+      return external_symbol_with_ascii_data_map();
+    case SHORT_EXTERNAL_STRING_TYPE: return short_external_symbol_map();
+    case SHORT_EXTERNAL_ASCII_STRING_TYPE:
+      return short_external_ascii_symbol_map();
+    case SHORT_EXTERNAL_STRING_WITH_ASCII_DATA_TYPE:
+      return short_external_symbol_with_ascii_data_map();
+    default: return NULL;  // No match found.
   }
-  if (map == string_map()) {
-    return symbol_map();
-  }
-  if (map == cons_string_map()) {
-    return cons_symbol_map();
-  }
-  if (map == cons_ascii_string_map()) {
-    return cons_ascii_symbol_map();
-  }
-  if (map == external_string_map()) {
-    return external_symbol_map();
-  }
-  if (map == external_ascii_string_map()) {
-    return external_ascii_symbol_map();
-  }
-  if (map == external_string_with_ascii_data_map()) {
-    return external_symbol_with_ascii_data_map();
-  }
-  if (map == short_external_string_map()) {
-    return short_external_symbol_map();
-  }
-  if (map == short_external_ascii_string_map()) {
-    return short_external_ascii_symbol_map();
-  }
-  if (map == short_external_string_with_ascii_data_map()) {
-    return short_external_symbol_with_ascii_data_map();
-  }
-
-  // No match found.
-  return NULL;
 }
 
 
 MaybeObject* Heap::AllocateInternalSymbol(unibrow::CharacterStream* buffer,
                                           int chars,
                                           uint32_t hash_field) {
   ASSERT(chars >= 0);
   // Ensure the chars matches the number of characters in the buffer.
   ASSERT(static_cast<unsigned>(chars) == buffer->Length());
   // Determine whether the string is ascii.
@@ skipping 2445 matching lines @@
   isolate_->heap()->store_buffer()->Compact();
   isolate_->heap()->store_buffer()->Filter(MemoryChunk::ABOUT_TO_BE_FREED);
   for (chunk = chunks_queued_for_free_; chunk != NULL; chunk = next) {
     next = chunk->next_chunk();
     isolate_->memory_allocator()->Free(chunk);
   }
   chunks_queued_for_free_ = NULL;
 }
 
 } }  // namespace v8::internal