Last cross-platform cleanup in preparation of improved ARM code for indexed

runtime/vm/intermediate_language_x64.cc

Index: runtime/vm/intermediate_language_x64.cc
===================================================================
--- runtime/vm/intermediate_language_x64.cc	(revision 36576)
+++ runtime/vm/intermediate_language_x64.cc	(working copy)
@@ -751,8 +751,8 @@
   const Object& constant = index->definition()->AsConstant()->value();
   if (!constant.IsSmi()) return false;
   const Smi& smi_const = Smi::Cast(constant);
-  const intptr_t scale = FlowGraphCompiler::ElementSizeFor(cid);
-  const intptr_t data_offset = FlowGraphCompiler::DataOffsetFor(cid);
+  const intptr_t scale = Instance::ElementSizeFor(cid);
+  const intptr_t data_offset = Instance::DataOffsetFor(cid);
   const int64_t disp = smi_const.AsInt64Value() * scale + data_offset;
   return Utils::IsInt(32, disp);
 }
@@ -973,30 +973,67 @@
 }
 
 
+static Address ElementAddressForIntIndex(bool is_external,
+                                         intptr_t cid,
+                                         intptr_t index_scale,
+                                         Register array,
+                                         intptr_t index) {
+  if (is_external) {
+    return Address(array, index * index_scale);
+  } else {
+    const int64_t disp = static_cast<int64_t>(index) * index_scale +
+        Instance::DataOffsetFor(cid);
+    ASSERT(Utils::IsInt(32, disp));
+    return FieldAddress(array, static_cast<int32_t>(disp));
+  }
+}
+
+
+static ScaleFactor ToScaleFactor(intptr_t index_scale) {
+  // Note that index is expected smi-tagged, (i.e, times 2) for all arrays with
+  // index scale factor > 1. E.g., for Uint8Array and OneByteString the index is
+  // expected to be untagged before accessing.
+  ASSERT(kSmiTagShift == 1);
+  switch (index_scale) {
+    case 1: return TIMES_1;
+    case 2: return TIMES_1;
+    case 4: return TIMES_2;
+    case 8: return TIMES_4;
+    case 16: return TIMES_8;
+    default:
+      UNREACHABLE();
+      return TIMES_1;
+  }
+}
+
+
+static Address ElementAddressForRegIndex(bool is_external,
+                                         intptr_t cid,
+                                         intptr_t index_scale,
+                                         Register array,
+                                         Register index) {
+  if (is_external) {
+    return Address(array, index, ToScaleFactor(index_scale), 0);
+  } else {
+    return FieldAddress(array,
+                        index,
+                        ToScaleFactor(index_scale),
+                        Instance::DataOffsetFor(cid));
+  }
+}
+
+
 void LoadIndexedInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   Register array = locs()->in(0).reg();
   Location index = locs()->in(1);
 
-  const bool is_external =
-      (this->array()->definition()->representation() == kUntagged);
   Address element_address(kNoRegister, 0);
+  element_address = index.IsRegister()
+      ? ElementAddressForRegIndex(IsExternal(), class_id(), index_scale(),
+                                  array, index.reg())
+      : ElementAddressForIntIndex(IsExternal(), class_id(), index_scale(),
+                                  array, Smi::Cast(index.constant()).Value());
 
-  if (is_external) {
-    element_address = index.IsRegister()
-        ? compiler->ExternalElementAddressForRegIndex(
-            index_scale(), array, index.reg())
-        : compiler->ExternalElementAddressForIntIndex(
-            index_scale(), array, Smi::Cast(index.constant()).Value());
-  } else {
-    ASSERT(this->array()->definition()->representation() == kTagged);
-    element_address = index.IsRegister()
-        ? compiler->ElementAddressForRegIndex(
-            class_id(), index_scale(), array, index.reg())
-        : compiler->ElementAddressForIntIndex(
-            class_id(), index_scale(), array,
-            Smi::Cast(index.constant()).Value());
-  }
-
   if ((representation() == kUnboxedDouble)    ||
       (representation() == kUnboxedFloat32x4) ||
       (representation() == kUnboxedInt32x4)   ||
@@ -1161,24 +1198,12 @@
   Register array = locs()->in(0).reg();
   Location index = locs()->in(1);
 
-  const bool is_external =
-      (this->array()->definition()->representation() == kUntagged);
   Address element_address(kNoRegister, 0);
-  if (is_external) {
-    element_address = index.IsRegister()
-        ? compiler->ExternalElementAddressForRegIndex(
-            index_scale(), array, index.reg())
-        : compiler->ExternalElementAddressForIntIndex(
-            index_scale(), array, Smi::Cast(index.constant()).Value());
-  } else {
-    ASSERT(this->array()->definition()->representation() == kTagged);
-    element_address = index.IsRegister()
-        ? compiler->ElementAddressForRegIndex(
-            class_id(), index_scale(), array, index.reg())
-        : compiler->ElementAddressForIntIndex(
-            class_id(), index_scale(), array,
-            Smi::Cast(index.constant()).Value());
-  }
+  element_address = index.IsRegister()
+      ? ElementAddressForRegIndex(IsExternal(), class_id(), index_scale(),
+                                  array, index.reg())
+      : ElementAddressForIntIndex(IsExternal(), class_id(), index_scale(),
+                                  array, Smi::Cast(index.constant()).Value());
 
   if ((index_scale() == 1) && index.IsRegister()) {
     __ SmiUntag(index.reg());