Add immediate operand support for indexed operations.

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 862 matching lines @@
   __ movq(RBX, Immediate(reinterpret_cast<uword>(native_c_function())));
   __ movq(R10, Immediate(arg_count));
   compiler->GenerateCall(token_pos(),
                          &StubCode::CallNativeCFunctionLabel(),
                          PcDescriptors::kOther,
                          locs());
   __ popq(result);
 }
 
 
+static bool CanBeIndexImmediate(Value* index) {
+  if (!index->definition()->IsConstant()) return false;
+  const Object& constant = index->definition()->AsConstant()->value();
+  const Smi& smi_const = Smi::Cast(constant);

[srdjan, 2012/09/12 12:56:16]

The reason why this works is because this code must have been run before
successfully, therefore the constant must be Smi. Correct?

[Florian Schneider, 2012/09/12 13:28:35]

Yes, and when optimizing we generate a smi-check for the index (which is
eliminated if the constant is indeed a smi).

+  int64_t disp = smi_const.AsInt64Value() * kWordSize + sizeof(RawArray);
+  return Utils::IsInt(32, disp);
+}
+
+
 LocationSummary* LoadIndexedInstr::MakeLocationSummary() const {
   const intptr_t kNumInputs = 2;
-  return LocationSummary::Make(kNumInputs,
-                               Location::RequiresRegister(),
-                               LocationSummary::kNoCall);
+  const intptr_t kNumTemps = 0;
+  LocationSummary* locs =
+      new LocationSummary(kNumInputs, kNumTemps, LocationSummary::kNoCall);
+  locs->set_in(0, Location::RequiresRegister());
+  locs->set_in(1, CanBeIndexImmediate(index())
+                    ? Location::RegisterOrConstant(index())
+                    : Location::RequiresRegister());
+  locs->set_out(Location::RequiresRegister());
+  return locs;
+}
+
+
+static int64_t RawSmi(const Object& constant) {
+  ASSERT(constant.IsSmi());
+  return reinterpret_cast<int64_t>(constant.raw());
 }
 
 
 void LoadIndexedInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   Register array = locs()->in(0).reg();
-  Register index = locs()->in(1).reg();
   Register result = locs()->out().reg();
 
   // Note that index is Smi, i.e, times 4.
   ASSERT(kSmiTagShift == 1);
-  __ movq(result, FieldAddress(array, index, TIMES_4, sizeof(RawArray)));
+  if (locs()->in(1).IsRegister()) {
+    Register index = locs()->in(1).reg();
+    __ movq(result, FieldAddress(array, index, TIMES_4, sizeof(RawArray)));
+  } else {
+    int64_t disp = RawSmi(locs()->in(1).constant()) * 4 + sizeof(RawArray);
+    ASSERT(Utils::IsInt(32, disp));
+    __ movq(result, FieldAddress(array, static_cast<int32_t>(disp)));
+  }
 }
 
 
 LocationSummary* StoreIndexedInstr::MakeLocationSummary() const {
   const intptr_t kNumInputs = 3;
   const intptr_t kNumTemps = 0;
   LocationSummary* locs =
       new LocationSummary(kNumInputs, kNumTemps, LocationSummary::kNoCall);
   locs->set_in(0, Location::RequiresRegister());
-  locs->set_in(1, Location::RequiresRegister());
-  locs->set_in(2, value()->NeedsStoreBuffer() ? Location::WritableRegister()
-                                              : Location::RequiresRegister());
+  locs->set_in(1, CanBeIndexImmediate(index())
+                    ? Location::RegisterOrConstant(index())
+                    : Location::RequiresRegister());
+  locs->set_in(2, value()->NeedsStoreBuffer()
+                    ? Location::WritableRegister()
+                    : Location::RegisterOrConstant(value()));
   return locs;
 }
 
 
 void StoreIndexedInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   Register array = locs()->in(0).reg();
-  Register index = locs()->in(1).reg();
-  Register value = locs()->in(2).reg();
 
   // Note that index is Smi, i.e, times 4.
   ASSERT(kSmiTagShift == 1);
+  FieldAddress field_address = locs()->in(1).IsConstant()
+      ? FieldAddress(
+          array,
+          static_cast<int32_t>(
+              RawSmi(locs()->in(1).constant()) * 4 + sizeof(RawArray)))
+      : FieldAddress(array, locs()->in(1).reg(), TIMES_4, sizeof(RawArray));
+
   if (this->value()->NeedsStoreBuffer()) {
-    __ StoreIntoObject(array,
-        FieldAddress(array, index, TIMES_4, sizeof(RawArray)),
-        value);
+      Register value = locs()->in(2).reg();
+    __ StoreIntoObject(array, field_address, value);
   } else {
-    __ StoreIntoObjectNoBarrier(array,
-        FieldAddress(array, index, TIMES_4, sizeof(RawArray)),
-        value);
+    if (locs()->in(2).IsConstant()) {
+      const Object& constant = locs()->in(2).constant();
+      __ StoreObject(field_address, constant);
+    } else {
+      Register value = locs()->in(2).reg();
+      __ StoreIntoObjectNoBarrier(array, field_address, value);
+    }
   }
 }
 
 
 LocationSummary* LoadInstanceFieldInstr::MakeLocationSummary() const {
   // TODO(fschneider): For this instruction the input register may be
   // reused for the result (but is not required to) because the input
   // is not used after the result is defined.  We should consider adding
   // this information to the input policy.
   return LocationSummary::Make(1,
@@ skipping 1362 matching lines @@
     __ j(ABOVE_EQUAL, deopt);
   }
 }
 
 
 }  // namespace dart
 
 #undef __
 
 #endif  // defined TARGET_ARCH_X64