Make maps in monomorphic IC stubs weak.

src/mark-compact.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 431 matching lines @@
   if (!FLAG_collect_maps) ReattachInitialMaps();
 
 #ifdef DEBUG
   if (FLAG_verify_native_context_separation) {
     VerifyNativeContextSeparation(heap_);
   }
 #endif
 
 #ifdef VERIFY_HEAP
   if (heap()->weak_embedded_objects_verification_enabled()) {
-    VerifyWeakEmbeddedObjectsInOptimizedCode();
+    VerifyWeakEmbeddedObjectsInCode();
   }
   if (FLAG_collect_maps && FLAG_omit_map_checks_for_leaf_maps) {
     VerifyOmittedMapChecks();
   }
 #endif
 
   Finish();
 
   if (marking_parity_ == EVEN_MARKING_PARITY) {
     marking_parity_ = ODD_MARKING_PARITY;
@@ skipping 40 matching lines @@
 
   LargeObjectIterator it(heap_->lo_space());
   for (HeapObject* obj = it.Next(); obj != NULL; obj = it.Next()) {
     MarkBit mark_bit = Marking::MarkBitFrom(obj);
     CHECK(Marking::IsWhite(mark_bit));
     CHECK_EQ(0, Page::FromAddress(obj->address())->LiveBytes());
   }
 }
 
 
-void MarkCompactCollector::VerifyWeakEmbeddedObjectsInOptimizedCode() {
+void MarkCompactCollector::VerifyWeakEmbeddedObjectsInCode() {
   HeapObjectIterator code_iterator(heap()->code_space());
   for (HeapObject* obj = code_iterator.Next();
        obj != NULL;
        obj = code_iterator.Next()) {
     Code* code = Code::cast(obj);
-    if (code->kind() != Code::OPTIMIZED_FUNCTION) continue;
+    if (!code->is_optimized_code() && !code->is_weak_stub()) continue;
     if (WillBeDeoptimized(code)) continue;
     code->VerifyEmbeddedObjectsDependency();
   }
 }
 
 
 void MarkCompactCollector::VerifyOmittedMapChecks() {
   HeapObjectIterator iterator(heap()->map_space());
   for (HeapObject* obj = iterator.Next();
        obj != NULL;
@@ skipping 2183 matching lines @@
   DisallowHeapAllocation no_allocation;
   DependentCode::GroupStartIndexes starts(entries);
   int number_of_entries = starts.number_of_entries();
   if (number_of_entries == 0) return;
   for (int i = 0; i < number_of_entries; i++) {
     // If the entry is compilation info then the map must be alive,
     // and ClearAndDeoptimizeDependentCode shouldn't be called.
     ASSERT(entries->is_code_at(i));
     Code* code = entries->code_at(i);
 
-    if (IsMarked(code) && !code->marked_for_deoptimization()) {
+    if (code->is_weak_stub()) {

[Toon Verwaest, 2014/04/03 15:18:36]

Also IsMarked(code)?

[ulan, 2014/04/03 15:40:26]

Good catch, done.

+      IC::InvalidateMapsAndHandlers(code);
+    } else if (IsMarked(code) && !code->marked_for_deoptimization()) {
       code->set_marked_for_deoptimization(true);
       code->InvalidateEmbeddedObjects();
       have_code_to_deoptimize_ = true;
     }
     entries->clear_at(i);
   }
 }
 
 
 void MarkCompactCollector::ClearNonLiveDependentCode(DependentCode* entries) {
@@ skipping 668 matching lines @@
     MarkBit mark_bit = Marking::MarkBitFrom(code);
     if (Marking::IsWhite(mark_bit)) return;
 
     invalidated_code_.Add(code);
   }
 }
 
 
 // Return true if the given code is deoptimized or will be deoptimized.
 bool MarkCompactCollector::WillBeDeoptimized(Code* code) {
-  return code->marked_for_deoptimization();
+  return code->is_optimized_code() && code->marked_for_deoptimization();
 }
 
 
 bool MarkCompactCollector::MarkInvalidatedCode() {
   bool code_marked = false;
 
   int length = invalidated_code_.length();
   for (int i = 0; i < length; i++) {
     Code* code = invalidated_code_[i];
 
@@ skipping 1101 matching lines @@
   while (buffer != NULL) {
     SlotsBuffer* next_buffer = buffer->next();
     DeallocateBuffer(buffer);
     buffer = next_buffer;
   }
   *buffer_address = NULL;
 }
 
 
 } }  // namespace v8::internal