Make embedded maps in optimized code weak.

src/heap.cc

Index: src/heap.cc
diff --git a/src/heap.cc b/src/heap.cc
index 43522ab8edc57a9e695d8b6359b4c43ae6b3e353..716a0301c64cdfa246fa14b2d24e282f93c6502e 100644
--- a/src/heap.cc
+++ b/src/heap.cc
@@ -2197,6 +2197,8 @@ MaybeObject* Heap::AllocateMap(InstanceType instance_type,
   map->set_inobject_properties(0);
   map->set_pre_allocated_property_fields(0);
   map->set_code_cache(empty_fixed_array(), SKIP_WRITE_BARRIER);
+  map->set_dependent_codes(DependentCodes::cast(empty_fixed_array()),
+                           SKIP_WRITE_BARRIER);
   map->init_back_pointer(undefined_value());
   map->set_unused_property_fields(0);
   map->set_instance_descriptors(empty_descriptor_array());
@@ -2332,14 +2334,18 @@ bool Heap::CreateInitialMaps() {
 
   // Fix the instance_descriptors for the existing maps.
   meta_map()->set_code_cache(empty_fixed_array());
+  meta_map()->set_dependent_codes(DependentCodes::cast(empty_fixed_array()));
   meta_map()->init_back_pointer(undefined_value());
   meta_map()->set_instance_descriptors(empty_descriptor_array());
 
   fixed_array_map()->set_code_cache(empty_fixed_array());
+  fixed_array_map()->set_dependent_codes(
+      DependentCodes::cast(empty_fixed_array()));
   fixed_array_map()->init_back_pointer(undefined_value());
   fixed_array_map()->set_instance_descriptors(empty_descriptor_array());
 
   oddball_map()->set_code_cache(empty_fixed_array());
+  oddball_map()->set_dependent_codes(DependentCodes::cast(empty_fixed_array()));
   oddball_map()->init_back_pointer(undefined_value());
   oddball_map()->set_instance_descriptors(empty_descriptor_array());
 
@@ -3788,6 +3794,9 @@ MaybeObject* Heap::CreateCode(const CodeDesc& desc,
   code->set_gc_metadata(Smi::FromInt(0));
   code->set_ic_age(global_ic_age_);
   code->set_prologue_offset(kPrologueOffsetNotSet);
+  if (code->kind() == Code::OPTIMIZED_FUNCTION) {
+    code->set_marked_for_deoptimization(false);
+  }
   // Allow self references to created code object by patching the handle to
   // point to the newly allocated Code object.
   if (!self_reference.is_null()) {