Make KeyedStores from a sloppy arguments array use a handler.

src/code-stubs-hydrogen.cc

Index: src/code-stubs-hydrogen.cc
diff --git a/src/code-stubs-hydrogen.cc b/src/code-stubs-hydrogen.cc
index b3899826167c13243cc4433ac281ee3d12066449..2b45050262683762658e6a7faf8997bacf679045 100644
--- a/src/code-stubs-hydrogen.cc
+++ b/src/code-stubs-hydrogen.cc
@@ -74,7 +74,9 @@ class CodeStubGraphBuilderBase : public HGraphBuilder {
     MULTIPLE
   };
 
-  HValue* UnmappedCase(HValue* elements, HValue* key);
+  HValue* UnmappedCase(HValue* elements, HValue* key, HValue* value);
+  HValue* EmitKeyedSloppyArguments(HValue* receiver, HValue* key,
+                                   HValue* value);
 
   HValue* BuildArrayConstructor(ElementsKind kind,
                                 AllocationSiteOverrideMode override_mode,
@@ -796,8 +798,9 @@ HValue* CodeStubGraphBuilder<LoadConstantStub>::BuildCodeStub() {
 Handle<Code> LoadConstantStub::GenerateCode() { return DoGenerateCode(this); }
 
 
-HValue* CodeStubGraphBuilderBase::UnmappedCase(HValue* elements, HValue* key) {
-  HValue* result;
+HValue* CodeStubGraphBuilderBase::UnmappedCase(HValue* elements, HValue* key,
+                                               HValue* value) {
+  HValue* result = NULL;
   HInstruction* backing_store =
       Add<HLoadKeyed>(elements, graph()->GetConstant1(), nullptr, FAST_ELEMENTS,
                       ALLOW_RETURN_HOLE);
@@ -809,8 +812,12 @@ HValue* CodeStubGraphBuilderBase::UnmappedCase(HValue* elements, HValue* key) {
                                                  Token::LT);
   in_unmapped_range.Then();
   {
-    result = Add<HLoadKeyed>(backing_store, key, nullptr, FAST_HOLEY_ELEMENTS,
-                             NEVER_RETURN_HOLE);
+    if (value == NULL) {
+      result = Add<HLoadKeyed>(backing_store, key, nullptr, FAST_HOLEY_ELEMENTS,
+                               NEVER_RETURN_HOLE);
+    } else {
+      Add<HStoreKeyed>(backing_store, key, value, FAST_HOLEY_ELEMENTS);
+    }
   }
   in_unmapped_range.ElseDeopt(Deoptimizer::kOutsideOfRange);
   in_unmapped_range.End();
@@ -818,11 +825,9 @@ HValue* CodeStubGraphBuilderBase::UnmappedCase(HValue* elements, HValue* key) {
 }
 
 
-template <>
-HValue* CodeStubGraphBuilder<KeyedLoadSloppyArgumentsStub>::BuildCodeStub() {
-  HValue* receiver = GetParameter(LoadDescriptor::kReceiverIndex);
-  HValue* key = GetParameter(LoadDescriptor::kNameIndex);
-
+HValue* CodeStubGraphBuilderBase::EmitKeyedSloppyArguments(HValue* receiver,
+                                                           HValue* key,
+                                                           HValue* value) {
   // Mapped arguments are actual arguments. Unmapped arguments are values added
   // to the arguments object after it was created for the call. Mapped arguments
   // are stored in the context at indexes given by elements[key + 2]. Unmapped
@@ -849,6 +854,8 @@ HValue* CodeStubGraphBuilder<KeyedLoadSloppyArgumentsStub>::BuildCodeStub() {
   // index into the context array given at elements[0]. Return the value at
   // context[t].
 
+  bool is_load = value == NULL;
+
   key = AddUncasted<HForceRepresentation>(key, Representation::Smi());
   IfBuilder positive_smi(this);
   positive_smi.If<HCompareNumericAndBranch>(key, graph()->GetConstant0(),
@@ -880,25 +887,39 @@ HValue* CodeStubGraphBuilder<KeyedLoadSloppyArgumentsStub>::BuildCodeStub() {
       HValue* the_context = Add<HLoadKeyed>(elements, graph()->GetConstant0(),
                                             nullptr, FAST_ELEMENTS);
       STATIC_ASSERT(Context::kHeaderSize == FixedArray::kHeaderSize);
-      HValue* result = Add<HLoadKeyed>(the_context, mapped_index, nullptr,
-                                       FAST_ELEMENTS, ALLOW_RETURN_HOLE);
-      environment()->Push(result);
+      if (is_load) {
+        HValue* result = Add<HLoadKeyed>(the_context, mapped_index, nullptr,
+                                         FAST_ELEMENTS, ALLOW_RETURN_HOLE);
+        environment()->Push(result);
+      } else {
+        DCHECK(value != NULL);
+        Add<HStoreKeyed>(the_context, mapped_index, value, FAST_ELEMENTS);
+      }
     }
     is_valid.Else();
     {
-      HValue* result = UnmappedCase(elements, key);
-      environment()->Push(result);
+      HValue* result = UnmappedCase(elements, key, value);
+      if (is_load) environment()->Push(result);

[Jakob Kummerow, 2015/05/28 11:55:00]

Doesn't the store stub need to return the value to allow chained assignments?
The handwritten stub appears to have done this implicitly by virtue of passing
in the value in eax and never overwriting it. I think you want
"environment()->Push(is_load ? result : value);" here.

[mvstanton, 2015/05/28 13:23:52]

Good idea, it's much cleaner that way.

     }
     is_valid.End();
   }
   in_range.Else();
   {
-    HValue* result = UnmappedCase(elements, key);
-    environment()->Push(result);
+    HValue* result = UnmappedCase(elements, key, value);
+    if (is_load) environment()->Push(result);
   }
   in_range.End();
 
-  return environment()->Pop();
+  return is_load ? environment()->Pop() : NULL;
+}
+
+
+template <>
+HValue* CodeStubGraphBuilder<KeyedLoadSloppyArgumentsStub>::BuildCodeStub() {
+  HValue* receiver = GetParameter(LoadDescriptor::kReceiverIndex);
+  HValue* key = GetParameter(LoadDescriptor::kNameIndex);
+
+  return EmitKeyedSloppyArguments(receiver, key, NULL);
 }
 
 
@@ -907,6 +928,22 @@ Handle<Code> KeyedLoadSloppyArgumentsStub::GenerateCode() {
 }
 
 
+template <>
+HValue* CodeStubGraphBuilder<KeyedStoreSloppyArgumentsStub>::BuildCodeStub() {
+  HValue* receiver = GetParameter(StoreDescriptor::kReceiverIndex);
+  HValue* key = GetParameter(StoreDescriptor::kNameIndex);
+  HValue* value = GetParameter(StoreDescriptor::kValueIndex);
+
+  EmitKeyedSloppyArguments(receiver, key, value);
+  return value;
+}
+
+
+Handle<Code> KeyedStoreSloppyArgumentsStub::GenerateCode() {
+  return DoGenerateCode(this);
+}
+
+
 void CodeStubGraphBuilderBase::BuildStoreNamedField(
     HValue* object, HValue* value, FieldIndex index,
     Representation representation, bool transition_to_field) {