Inline [] operator on one-byte strings.

runtime/vm/intermediate_language_x64.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_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/intermediate_language.h"
 
 #include "lib/error.h"
@@ skipping 974 matching lines @@
     // Don't untag smi-index and use TIMES_1 for two byte strings.
     __ movzxw(result, FieldAddress(str,
                                    index,
                                    TIMES_1,
                                    TwoByteString::data_offset()));
     __ SmiTag(result);
   }
 }
 
 
+LocationSummary* StringFromCharCodeInstr::MakeLocationSummary() const {
+  const intptr_t kNumInputs = 1;
+  const intptr_t kNumTemps = 0;
+  LocationSummary* locs =
+      new LocationSummary(kNumInputs, kNumTemps, LocationSummary::kNoCall);
+  // TODO(fschneider): Allow immediate operands for the char code.
+  locs->set_in(0, Location::RequiresRegister());
+  locs->set_out(Location::RequiresRegister());
+  return locs;
+}
+
+
+void StringFromCharCodeInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
+  Register char_code = locs()->in(0).reg();
+  Register result = locs()->out().reg();
+  __ movq(result,
+          Immediate(reinterpret_cast<uword>(Symbols::PredefinedAddress())));
+  __ movq(result, Address(result,
+                          char_code,
+                          TIMES_HALF_WORD_SIZE,  // Char code is a smi.
+                          Symbols::kNullCharId * kWordSize));
+}
+
+
 LocationSummary* LoadIndexedInstr::MakeLocationSummary() const {
   const intptr_t kNumInputs = 2;
   const intptr_t kNumTemps = 0;
   LocationSummary* locs =
       new LocationSummary(kNumInputs, kNumTemps, LocationSummary::kNoCall);
   locs->set_in(0, Location::RequiresRegister());
   locs->set_in(1, CanBeImmediateIndex(index())
                     ? Location::RegisterOrConstant(index())
                     : Location::RequiresRegister());
   if (representation() == kUnboxedDouble) {
@@ skipping 1368 matching lines @@
 
 void ShiftMintOpInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   UNIMPLEMENTED();
 }
 
 }  // namespace dart
 
 #undef __
 
 #endif  // defined TARGET_ARCH_X64