[cleanup] Drop FLAG_eliminate_prototype_chain_checks

src/ic/mips/handler-compiler-mips.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if V8_TARGET_ARCH_MIPS
 
 #include "src/ic/handler-compiler.h"
 
 #include "src/api-arguments.h"
 #include "src/field-type.h"
@@ skipping 405 matching lines @@
     Register object_reg, Register holder_reg, Register scratch1,
     Register scratch2, Handle<Name> name, Label* miss, PrototypeCheckType check,
     ReturnHolder return_what) {
   Handle<Map> receiver_map = map();
 
   // Make sure there's no overlap between holder and object registers.
   DCHECK(!scratch1.is(object_reg) && !scratch1.is(holder_reg));
   DCHECK(!scratch2.is(object_reg) && !scratch2.is(holder_reg) &&
          !scratch2.is(scratch1));
 
-  if (FLAG_eliminate_prototype_chain_checks) {
-    Handle<Cell> validity_cell =
-        Map::GetOrCreatePrototypeChainValidityCell(receiver_map, isolate());
-    if (!validity_cell.is_null()) {
-      DCHECK_EQ(Smi::FromInt(Map::kPrototypeChainValid),
-                validity_cell->value());
-      __ li(scratch1, Operand(validity_cell));
-      __ lw(scratch1, FieldMemOperand(scratch1, Cell::kValueOffset));
-      __ Branch(miss, ne, scratch1,
-                Operand(Smi::FromInt(Map::kPrototypeChainValid)));
-    }
+  Handle<Cell> validity_cell =
+      Map::GetOrCreatePrototypeChainValidityCell(receiver_map, isolate());
+  if (!validity_cell.is_null()) {
+    DCHECK_EQ(Smi::FromInt(Map::kPrototypeChainValid), validity_cell->value());
+    __ li(scratch1, Operand(validity_cell));
+    __ lw(scratch1, FieldMemOperand(scratch1, Cell::kValueOffset));
+    __ Branch(miss, ne, scratch1,
+              Operand(Smi::FromInt(Map::kPrototypeChainValid)));
+  }
 
-    // The prototype chain of primitives (and their JSValue wrappers) depends
-    // on the native context, which can't be guarded by validity cells.
-    // |object_reg| holds the native context specific prototype in this case;
-    // we need to check its map.
-    if (check == CHECK_ALL_MAPS) {
-      __ lw(scratch1, FieldMemOperand(object_reg, HeapObject::kMapOffset));
-      Handle<WeakCell> cell = Map::WeakCellForMap(receiver_map);
-      __ GetWeakValue(scratch2, cell);
-      __ Branch(miss, ne, scratch1, Operand(scratch2));
-    }
+  // The prototype chain of primitives (and their JSValue wrappers) depends
+  // on the native context, which can't be guarded by validity cells.
+  // |object_reg| holds the native context specific prototype in this case;
+  // we need to check its map.
+  if (check == CHECK_ALL_MAPS) {
+    __ lw(scratch1, FieldMemOperand(object_reg, HeapObject::kMapOffset));
+    Handle<WeakCell> cell = Map::WeakCellForMap(receiver_map);
+    __ GetWeakValue(scratch2, cell);
+    __ Branch(miss, ne, scratch1, Operand(scratch2));
   }
 
   // Keep track of the current object in register reg.
   Register reg = object_reg;
   int depth = 0;
 
   Handle<JSObject> current = Handle<JSObject>::null();
   if (receiver_map->IsJSGlobalObjectMap()) {
     current = isolate()->global_object();
   }
@@ skipping 15 matching lines @@
   // fast and global objects or do negative lookup for normal objects.
   while (!current_map.is_identical_to(holder_map)) {
     ++depth;
 
     // Only global objects and objects that do not require access
     // checks are allowed in stubs.
     DCHECK(current_map->IsJSGlobalProxyMap() ||
            !current_map->is_access_check_needed());
 
     prototype = handle(JSObject::cast(current_map->prototype()));
-    if (current_map->is_dictionary_map() &&
-        !current_map->IsJSGlobalObjectMap()) {
+    if (current_map->IsJSGlobalObjectMap()) {
+      GenerateCheckPropertyCell(masm(), Handle<JSGlobalObject>::cast(current),
+                                name, scratch2, miss);
+    } else if (current_map->is_dictionary_map()) {
       DCHECK(!current_map->IsJSGlobalProxyMap());  // Proxy maps are fast.
       if (!name->IsUniqueName()) {
         DCHECK(name->IsString());
         name = factory()->InternalizeString(Handle<String>::cast(name));
       }
       DCHECK(current.is_null() ||
              current->property_dictionary()->FindEntry(name) ==
                  NameDictionary::kNotFound);
 
-      if (FLAG_eliminate_prototype_chain_checks && depth > 1) {
+      if (depth > 1) {
         // TODO(jkummerow): Cache and re-use weak cell.
         __ LoadWeakValue(reg, isolate()->factory()->NewWeakCell(current), miss);
       }
       GenerateDictionaryNegativeLookup(masm(), miss, reg, name, scratch1,
                                        scratch2);
-      if (!FLAG_eliminate_prototype_chain_checks) {
-        __ lw(scratch1, FieldMemOperand(reg, HeapObject::kMapOffset));
-        __ lw(holder_reg, FieldMemOperand(scratch1, Map::kPrototypeOffset));
-      }
-    } else {
-      Register map_reg = scratch1;
-      if (!FLAG_eliminate_prototype_chain_checks) {
-        __ lw(map_reg, FieldMemOperand(reg, HeapObject::kMapOffset));
-      }
-      if (current_map->IsJSGlobalObjectMap()) {
-        GenerateCheckPropertyCell(masm(), Handle<JSGlobalObject>::cast(current),
-                                  name, scratch2, miss);
-      } else if (!FLAG_eliminate_prototype_chain_checks &&
-                 (depth != 1 || check == CHECK_ALL_MAPS)) {
-        Handle<WeakCell> cell = Map::WeakCellForMap(current_map);
-        __ GetWeakValue(scratch2, cell);
-        __ Branch(miss, ne, scratch2, Operand(map_reg));
-      }
-      if (!FLAG_eliminate_prototype_chain_checks) {
-        __ lw(holder_reg, FieldMemOperand(map_reg, Map::kPrototypeOffset));
-      }
     }
 
     reg = holder_reg;  // From now on the object will be in holder_reg.
     // Go to the next object in the prototype chain.
     current = prototype;
     current_map = handle(current->map());
   }
 
   DCHECK(!current_map->IsJSGlobalProxyMap());
 
   // Log the check depth.
   LOG(isolate(), IntEvent("check-maps-depth", depth + 1));
 
-  if (!FLAG_eliminate_prototype_chain_checks &&
-      (depth != 0 || check == CHECK_ALL_MAPS)) {
-    // Check the holder map.
-    __ lw(scratch1, FieldMemOperand(reg, HeapObject::kMapOffset));
-    Handle<WeakCell> cell = Map::WeakCellForMap(current_map);
-    __ GetWeakValue(scratch2, cell);
-    __ Branch(miss, ne, scratch2, Operand(scratch1));
-  }
-
   bool return_holder = return_what == RETURN_HOLDER;
-  if (FLAG_eliminate_prototype_chain_checks && return_holder && depth != 0) {
+  if (return_holder && depth != 0) {
     __ LoadWeakValue(reg, isolate()->factory()->NewWeakCell(current), miss);
   }
 
   // Return the register containing the holder.
   return return_holder ? reg : no_reg;
 }
 
 
 void NamedLoadHandlerCompiler::FrontendFooter(Handle<Name> name, Label* miss) {
   if (!miss->is_unused()) {
@@ skipping 165 matching lines @@
   // Return the generated code.
   return GetCode(kind(), name);
 }
 
 
 #undef __
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_MIPS