Support immediate operands for array bounds checks.

runtime/vm/intermediate_language_ia32.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_IA32.
 #if defined(TARGET_ARCH_IA32)
 
 #include "vm/intermediate_language.h"
 
 #include "lib/error.h"
@@ skipping 2207 matching lines @@
 void CheckSmiComp::EmitNativeCode(FlowGraphCompiler* compiler) {
   Register value = locs()->in(0).reg();
   Label* deopt = compiler->AddDeoptStub(deopt_id(),
                                         kDeoptCheckSmi);
   __ testl(value, Immediate(kSmiTagMask));
   __ j(NOT_ZERO, deopt);
 }
 
 
 LocationSummary* CheckArrayBoundComp::MakeLocationSummary() const {
-  return LocationSummary::Make(2,
+  const intptr_t kNumInputs = 2;
+  ConstantComp* constant_index = index()->definition()->AsConstant();
+  if (constant_index != NULL) {
+  const intptr_t kNumTemps = 0;
+    LocationSummary* locs =
+        new LocationSummary(kNumInputs, kNumTemps, LocationSummary::kNoCall);
+    locs->set_in(0, Location::RequiresRegister());
+    locs->set_in(1, Location::Constant(constant_index->value()));

[Vyacheslav Egorov (Google), 2012/09/04 14:38:41]

I recommend creating a helper RegisterOrConstant that returns either
RequiresRegister() location or Constant location.

+    return locs;
+  }
+  return LocationSummary::Make(kNumInputs,
                                Location::NoLocation(),
                                LocationSummary::kNoCall);
 }
 
 
 void CheckArrayBoundComp::EmitNativeCode(FlowGraphCompiler* compiler) {
   Register receiver = locs()->in(0).reg();
-  Register index = locs()->in(1).reg();
 
   const DeoptReasonId deopt_reason =
       (array_type() == kGrowableObjectArrayCid) ?
       kDeoptLoadIndexedGrowableArray : kDeoptLoadIndexedFixedArray;
   Label* deopt = compiler->AddDeoptStub(deopt_id(),
                                         deopt_reason);
-  switch (array_type()) {
-    case kArrayCid:
-    case kImmutableArrayCid:
-      __ cmpl(index, FieldAddress(receiver, Array::length_offset()));
-      break;
-    case kGrowableObjectArrayCid:
-      __ cmpl(index,
-              FieldAddress(receiver, GrowableObjectArray::length_offset()));
-      break;
+  ASSERT(array_type() == kArrayCid ||
+         array_type() == kImmutableArrayCid ||
+         array_type() == kGrowableObjectArrayCid);
+  intptr_t length_offset = (array_type() == kGrowableObjectArrayCid)
+      ? GrowableObjectArray::length_offset()
+      : Array::length_offset();
+
+  if (locs()->in(1).IsConstant()) {
+    const Object& constant = locs()->in(1).constant();
+    ASSERT(constant.IsSmi());
+    const int32_t imm =
+        reinterpret_cast<int32_t>(constant.raw());
+    __ cmpl(FieldAddress(receiver, length_offset), Immediate(imm));
+    __ j(BELOW_EQUAL, deopt);
+  } else {
+    Register index = locs()->in(1).reg();
+    __ cmpl(index, FieldAddress(receiver, length_offset));
+    __ j(ABOVE_EQUAL, deopt);
   }
-  __ j(ABOVE_EQUAL, deopt);
 }
 
 
 }  // namespace dart
 
 #undef __
 
 #endif  // defined TARGET_ARCH_X64