Ensure integrity of ASCII strings.

src/heap.cc

 // Copyright 2012 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 3308 matching lines @@
 
 
 MaybeObject* Heap::AllocateExternalStringFromAscii(
     const ExternalAsciiString::Resource* resource) {
   size_t length = resource->length();
   if (length > static_cast<size_t>(String::kMaxLength)) {
     isolate()->context()->mark_out_of_memory();
     return Failure::OutOfMemoryException();
   }
 
+  ASSERT(String::IsAscii(resource->data(), length));
+
   Map* map = external_ascii_string_map();
   Object* result;
   { MaybeObject* maybe_result = Allocate(map, NEW_SPACE);
     if (!maybe_result->ToObject(&result)) return maybe_result;
   }
 
   ExternalAsciiString* external_string = ExternalAsciiString::cast(result);
   external_string->set_length(static_cast<int>(length));
   external_string->set_hash_field(String::kEmptyHashField);
   external_string->set_resource(resource);
@@ skipping 1144 matching lines @@
   Object* result;
   { MaybeObject* maybe_result = AllocateRaw(size, space, retry_space);
     if (!maybe_result->ToObject(&result)) return maybe_result;
   }
 
   // Partially initialize the object.
   HeapObject::cast(result)->set_map_no_write_barrier(ascii_string_map());
   String::cast(result)->set_length(length);
   String::cast(result)->set_hash_field(String::kEmptyHashField);
   ASSERT_EQ(size, HeapObject::cast(result)->Size());
+
+#ifdef DEBUG
+  if (FLAG_verify_heap) {
+    // Initialize string's content to ensure ASCII-ness (character range 0-127)
+    // as required when verifying the heap.
+    char* dest = SeqAsciiString::cast(result)->GetChars();
+    memset(dest, 0x0F, length * kCharSize);
+  }
+#endif  // DEBUG
+
   return result;
 }
 
 
 MaybeObject* Heap::AllocateRawTwoByteString(int length,
                                             PretenureFlag pretenure) {
   if (length < 0 || length > SeqTwoByteString::kMaxLength) {
     return Failure::OutOfMemoryException();
   }
   int size = SeqTwoByteString::SizeFor(length);
@@ skipping 2629 matching lines @@
   } else {
     p ^= 0x1d1ed & (Page::kPageSize - 1);  // I died.
   }
   remembered_unmapped_pages_[remembered_unmapped_pages_index_] =
       reinterpret_cast<Address>(p);
   remembered_unmapped_pages_index_++;
   remembered_unmapped_pages_index_ %= kRememberedUnmappedPages;
 }
 
 } }  // namespace v8::internal