[csa] Extract LoadNumberDictionaryElement from AccessorAssembler

This CL extracts code for loading a NumberDictionary element
from "EmitElementLoad" to its own function in the CSA.

This is done in preparation for a fast path in Torque for dictionary
elements.

R=jgruber@chromium.org

Change-Id: I3bb9897910183cd50be127bae771e531a61d57be
Reviewed-on: https://chromium-review.googlesource.com/1090832Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Commit-Queue: Simon Zünd <szuend@google.com>
Cr-Commit-Position: refs/heads/master@{#53586}

src/code-stub-assembler.cc

@@ -7272,6 +7272,26 @@ void CodeStubAssembler::NumberDictionaryLookup(
   }
 }
 
+TNode<Object> CodeStubAssembler::LoadNumberDictionaryElement(
+    TNode<NumberDictionary> dictionary, TNode<IntPtrT> intptr_index,
+    Label* not_data, Label* if_hole) {
+  TVARIABLE(IntPtrT, var_entry);
+  Label if_found(this);
+  NumberDictionaryLookup(dictionary, intptr_index, &if_found, &var_entry,
+                         if_hole);
+  BIND(&if_found);
+
+  // Check that the value is a data property.
+  TNode<IntPtrT> index = EntryToIndex<NumberDictionary>(var_entry.value());
+  TNode<Uint32T> details =
+      LoadDetailsByKeyIndex<NumberDictionary>(dictionary, index);
+  TNode<Uint32T> kind = DecodeWord32<PropertyDetails::KindField>(details);
+  // TODO(jkummerow): Support accessors without missing?
+  GotoIfNot(Word32Equal(kind, Int32Constant(kData)), not_data);
+  // Finally, load athe value.
+  return LoadValueByKeyIndex<NumberDictionary>(dictionary, index);
+}
+
 template <class Dictionary>
 void CodeStubAssembler::FindInsertionEntry(TNode<Dictionary> dictionary,
                                            TNode<Name> key,

src/code-stub-assembler.h

@@ -2044,6 +2044,10 @@ class V8_EXPORT_PRIVATE CodeStubAssembler : public compiler::CodeAssembler {
                               TVariable<IntPtrT>* var_entry,
                               Label* if_not_found);
 
+  TNode<Object> LoadNumberDictionaryElement(TNode<NumberDictionary> dictionary,
+                                            TNode<IntPtrT> intptr_index,
+                                            Label* not_data, Label* if_hole);
+
   template <class Dictionary>
   void FindInsertionEntry(TNode<Dictionary> dictionary, TNode<Name> key,
                           TVariable<IntPtrT>* var_key_index);

src/ic/accessor-assembler.cc

@@ -1800,19 +1800,10 @@ void AccessorAssembler::EmitElementLoad(
   {
     Comment("dictionary elements");
     GotoIf(IntPtrLessThan(intptr_index, IntPtrConstant(0)), out_of_bounds);
-    TVARIABLE(IntPtrT, var_entry);
-    Label if_found(this);
-    NumberDictionaryLookup(CAST(elements), intptr_index, &if_found, &var_entry,
-                           if_hole);
-    BIND(&if_found);
-    // Check that the value is a data property.
-    TNode<IntPtrT> index = EntryToIndex<NumberDictionary>(var_entry.value());
-    Node* details = LoadDetailsByKeyIndex<NumberDictionary>(elements, index);
-    Node* kind = DecodeWord32<PropertyDetails::KindField>(details);
-    // TODO(jkummerow): Support accessors without missing?
-    GotoIfNot(Word32Equal(kind, Int32Constant(kData)), miss);
-    // Finally, load the value.
-    exit_point->Return(LoadValueByKeyIndex<NumberDictionary>(elements, index));
+
+    TNode<Object> value = LoadNumberDictionaryElement(
+        CAST(elements), intptr_index, miss, if_hole);
+    exit_point->Return(value);
   }
 
   BIND(&if_typed_array);