Immediate index operand for string [] and streamline code for generating array ops.

runtime/vm/flow_graph_compiler.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_XXX.
 
 #include "vm/flow_graph_compiler.h"
 
 #include "vm/cha.h"
 #include "vm/dart_entry.h"
@@ skipping 1009 matching lines @@
     case BELOW_EQUAL:   return unsigned_left <= unsigned_right;
     case ABOVE:         return unsigned_left > unsigned_right;
     case ABOVE_EQUAL:   return unsigned_left >= unsigned_right;
     default:
       UNIMPLEMENTED();
       return false;
   }
 }
 
 
+intptr_t FlowGraphCompiler::ElementSizeFor(intptr_t cid) {
+  switch (cid) {
+    case kArrayCid:
+    case kImmutableArrayCid:
+      return Array::kBytesPerElement;
+    case kFloat32ArrayCid:
+      return Float32Array::kBytesPerElement;
+    case kFloat64ArrayCid:
+      return Float64Array::kBytesPerElement;
+    case kUint8ArrayCid:
+      return Uint8Array::kBytesPerElement;
+    case kUint8ClampedArrayCid:
+      return Uint8ClampedArray::kBytesPerElement;
+    case kOneByteStringCid:
+      return OneByteString::kBytesPerElement;
+    case kTwoByteStringCid:
+      return TwoByteString::kBytesPerElement;
+    default:
+      UNIMPLEMENTED();
+      return 0;
+  }
+}
+
+
+intptr_t FlowGraphCompiler::DataOffsetFor(intptr_t cid) {
+  switch (cid) {
+    case kArrayCid:
+    case kImmutableArrayCid:
+      return Array::data_offset();
+    case kFloat32ArrayCid:
+      return Float32Array::data_offset();
+    case kFloat64ArrayCid:
+      return Float64Array::data_offset();
+    case kUint8ArrayCid:
+      return Uint8Array::data_offset();
+    case kUint8ClampedArrayCid:
+      return Uint8ClampedArray::data_offset();
+    case kOneByteStringCid:
+      return OneByteString::data_offset();
+    case kTwoByteStringCid:
+      return TwoByteString::data_offset();
+    default:
+      UNIMPLEMENTED();
+      return Array::data_offset();
+  }
+}
+
+
 FieldAddress FlowGraphCompiler::ElementAddressForIntIndex(intptr_t cid,
                                                           Register array,
-                                                          intptr_t offset) {
-  switch (cid) {
-    case kArrayCid:
-    case kImmutableArrayCid: {
-      const intptr_t disp = offset * kWordSize + sizeof(RawArray);
-      ASSERT(Utils::IsInt(31, disp));
-      return FieldAddress(array, disp);
-    }
-    case kFloat32ArrayCid: {
-      const intptr_t disp =
-          offset * kFloatSize + Float32Array::data_offset();
-      ASSERT(Utils::IsInt(31, disp));
-      return FieldAddress(array, disp);
-    }
-    case kFloat64ArrayCid: {
-      const intptr_t disp =
-          offset * kDoubleSize + Float64Array::data_offset();
-      ASSERT(Utils::IsInt(31, disp));
-      return FieldAddress(array, disp);
-    }
-    case kUint8ArrayCid: {
-      const intptr_t disp = offset + Uint8Array::data_offset();
-      ASSERT(Utils::IsInt(31, disp));
-      return FieldAddress(array, disp);
-    }
-    case kUint8ClampedArrayCid: {
-      const intptr_t disp = offset + Uint8ClampedArray::data_offset();
-      ASSERT(Utils::IsInt(31, disp));
-      return FieldAddress(array, disp);
-    }
-    default:
-      UNIMPLEMENTED();
-      return FieldAddress(SPREG, 0);
-  }
+                                                          intptr_t index) {
+  const intptr_t disp = index * ElementSizeFor(cid) + DataOffsetFor(cid);
+  ASSERT(Utils::IsInt(31, disp));
+  return FieldAddress(array, disp);
 }
 
 
 FieldAddress FlowGraphCompiler::ElementAddressForRegIndex(intptr_t cid,
                                                           Register array,
                                                           Register index) {
-  // Note that index is Smi, i.e, times 2.
+  // Note that index is smi-tagged, (i.e, times 2) for all arrays with element
+  // size > 1. For Uint8Array and OneByteString the index is expected to be
+  // untagged before accessing.
   ASSERT(kSmiTagShift == 1);
   switch (cid) {
     case kArrayCid:
     case kImmutableArrayCid:
-      return FieldAddress(array, index, TIMES_HALF_WORD_SIZE, sizeof(RawArray));
+      return FieldAddress(
+          array, index, TIMES_HALF_WORD_SIZE, Array::data_offset());
     case kFloat32ArrayCid:
       return FieldAddress(array, index, TIMES_2, Float32Array::data_offset());
     case kFloat64ArrayCid:
       return FieldAddress(array, index, TIMES_4, Float64Array::data_offset());
     case kUint8ArrayCid:
       return FieldAddress(array, index, TIMES_1, Uint8Array::data_offset());
     case kUint8ClampedArrayCid:
       return
           FieldAddress(array, index, TIMES_1, Uint8ClampedArray::data_offset());
+    case kOneByteStringCid:
+      return FieldAddress(array, index, TIMES_1, OneByteString::data_offset());
+    case kTwoByteStringCid:
+      return FieldAddress(array, index, TIMES_1, TwoByteString::data_offset());
     default:
       UNIMPLEMENTED();
       return FieldAddress(SPREG, 0);
   }
 }
 
 
 // Returns true if checking against this type is a direct class id comparison.
 bool FlowGraphCompiler::TypeCheckAsClassEquality(const AbstractType& type) {
   ASSERT(type.IsFinalized() && !type.IsMalformed());
@@ skipping 13 matching lines @@
     const AbstractTypeArguments& type_arguments =
         AbstractTypeArguments::Handle(type.arguments());
     const bool is_raw_type = type_arguments.IsNull() ||
         type_arguments.IsRaw(type_arguments.Length());
     return is_raw_type;
   }
   return true;
 }
 
 }  // namespace dart