Remove custom weak handling of monomorphic IC.

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index 065b77281abaf7b78625fa599c81f47de08b79d2..414306f2b465553ed3dfe839f37347583d22996b 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -11924,23 +11924,6 @@ void Map::AddDependentCode(Handle<Map> map,
 }
 
 
-// static
-void Map::AddDependentIC(Handle<Map> map,
-                         Handle<Code> stub) {
-  DCHECK(stub->next_code_link()->IsUndefined());
-  int n = map->dependent_code()->number_of_entries(DependentCode::kWeakICGroup);
-  if (n == 0) {
-    // Slow path: insert the head of the list with possible heap allocation.
-    Map::AddDependentCode(map, DependentCode::kWeakICGroup, stub);
-  } else {
-    // Fast path: link the stub to the existing head of the list without any
-    // heap allocation.
-    DCHECK(n == 1);
-    map->dependent_code()->AddToDependentICList(stub);
-  }
-}
-
-
 DependentCode::GroupStartIndexes::GroupStartIndexes(DependentCode* entries) {
   Recompute(entries);
 }
@@ -12070,22 +12053,10 @@ void DependentCode::RemoveCompilationInfo(DependentCode::DependencyGroup group,
 }
 
 
-static bool CodeListContains(Object* head, Code* code) {
-  while (!head->IsUndefined()) {
-    if (head == code) return true;
-    head = Code::cast(head)->next_code_link();
-  }
-  return false;
-}
-
-
 bool DependentCode::Contains(DependencyGroup group, Code* code) {
   GroupStartIndexes starts(this);
   int start = starts.at(group);
   int end = starts.at(group + 1);
-  if (group == kWeakICGroup) {
-    return CodeListContains(object_at(start), code);
-  }
   for (int i = start; i < end; i++) {
     if (object_at(i) == code) return true;
   }
@@ -12142,24 +12113,6 @@ void DependentCode::DeoptimizeDependentCodeGroup(
 }
 
 
-void DependentCode::AddToDependentICList(Handle<Code> stub) {
-  DisallowHeapAllocation no_heap_allocation;
-  GroupStartIndexes starts(this);
-  int i = starts.at(kWeakICGroup);
-  Object* head = object_at(i);
-  // Try to insert the stub after the head of the list to minimize number of
-  // writes to the DependentCode array, since a write to the array can make it
-  // strong if it was alread marked by incremental marker.
-  if (head->IsCode()) {
-    stub->set_next_code_link(Code::cast(head)->next_code_link());
-    Code::cast(head)->set_next_code_link(*stub);
-  } else {
-    stub->set_next_code_link(head);
-    set_object_at(i, *stub);
-  }
-}
-
-
 void DependentCode::SetMarkedForDeoptimization(Code* code,
                                                DependencyGroup group) {
   code->set_marked_for_deoptimization(true);
@@ -12178,8 +12131,6 @@ void DependentCode::SetMarkedForDeoptimization(Code* code,
 
 const char* DependentCode::DependencyGroupName(DependencyGroup group) {
   switch (group) {
-    case kWeakICGroup:
-      return "weak-ic";
     case kWeakCodeGroup:
       return "weak-code";
     case kTransitionGroup: