Split GuardField into GuardFieldType and GuardFieldLength instructions.

runtime/vm/intermediate_language.cc

 // Copyright (c) 2013, 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/intermediate_language.h"
 
 #include "vm/bigint_operations.h"
 #include "vm/bit_vector.h"
 #include "vm/cpu.h"
 #include "vm/dart_entry.h"
@@ skipping 201 matching lines @@
       case kFloat64x2Cid:
         return kUnboxedFloat64x2;
       default:
         UNREACHABLE();
     }
   }
   return kTagged;
 }
 
 
-bool GuardFieldInstr::AttributesEqual(Instruction* other) const {
-  return field().raw() == other->AsGuardField()->field().raw();
+bool GuardFieldClassInstr::AttributesEqual(Instruction* other) const {
+  return field().raw() == other->AsGuardFieldClass()->field().raw();
 }
 
 
+bool GuardFieldLengthInstr::AttributesEqual(Instruction* other) const {
+  return field().raw() == other->AsGuardFieldLength()->field().raw();
+}
+
+
 bool AssertAssignableInstr::AttributesEqual(Instruction* other) const {
   AssertAssignableInstr* other_assert = other->AsAssertAssignable();
   ASSERT(other_assert != NULL);
   // This predicate has to be commutative for DominatorBasedCSE to work.
   // TODO(fschneider): Eliminate more asserts with subtype relation.
   return dst_type().raw() == other_assert->dst_type().raw();
 }
 
 
 bool StrictCompareInstr::AttributesEqual(Instruction* other) const {
@@ skipping 1710 matching lines @@
   Definition* replacement = CanonicalizeStrictCompare(this, &negated);
   if (negated && replacement->IsComparison()) {
     ASSERT(replacement != this);
     replacement->AsComparison()->NegateComparison();
   }
   return replacement;
 }
 
 
 Instruction* CheckClassInstr::Canonicalize(FlowGraph* flow_graph) {
-  // TODO(vegorov): Replace class checks with null checks when ToNullableCid
-  // matches.
-
   const intptr_t value_cid = value()->Type()->ToCid();
   if (value_cid == kDynamicCid) {
     return this;
   }
 
   return unary_checks().HasReceiverClassId(value_cid) ? NULL : this;
 }
 
 
-Instruction* GuardFieldInstr::Canonicalize(FlowGraph* flow_graph) {
+Instruction* GuardFieldClassInstr::Canonicalize(FlowGraph* flow_graph) {
   if (field().guarded_cid() == kDynamicCid) {
     return NULL;  // Nothing to guard.
   }
 
-  if (field().guarded_list_length() != Field::kNoFixedLength) {
-    // We are still guarding the list length. Check if length is statically
-    // known.
-    StaticCallInstr* call = value()->definition()->AsStaticCall();
-    if (call != NULL) {
-      ConstantInstr* length = NULL;
-      if (call->is_known_list_constructor() &&
-          LoadFieldInstr::IsFixedLengthArrayCid(call->Type()->ToCid())) {
-        length = call->ArgumentAt(1)->AsConstant();
-      }
-      if (call->is_native_list_factory()) {
-        length = call->ArgumentAt(0)->AsConstant();
-      }
-      if ((length != NULL) && length->value().IsSmi()) {
-        intptr_t known_length = Smi::Cast(length->value()).Value();
-        return (known_length != field().guarded_list_length()) ? this : NULL;
-      }
-    }
-    return this;
-  }
-
   if (field().is_nullable() && value()->Type()->IsNull()) {
     return NULL;
   }
 
   const intptr_t cid = field().is_nullable() ? value()->Type()->ToNullableCid()
                                              : value()->Type()->ToCid();
   if (field().guarded_cid() == cid) {
     return NULL;  // Value is guaranteed to have this cid.
   }
 
   return this;
 }
 
 
+Instruction* GuardFieldLengthInstr::Canonicalize(FlowGraph* flow_graph) {
+  if (!field().needs_length_check()) {
+    return NULL;  // Nothing to guard.
+  }
+
+  const intptr_t expected_length = field().guarded_list_length();
+  if (expected_length == Field::kUnknownFixedLength) {
+    return this;
+  }
+
+  // Check if length is statically known.
+  StaticCallInstr* call = value()->definition()->AsStaticCall();
+  if (call == NULL) {
+    return this;
+  }
+
+  ConstantInstr* length = NULL;
+  if (call->is_known_list_constructor() &&
+      LoadFieldInstr::IsFixedLengthArrayCid(call->Type()->ToCid())) {
+    length = call->ArgumentAt(1)->AsConstant();
+  }
+  if (call->is_native_list_factory()) {
+    length = call->ArgumentAt(0)->AsConstant();
+  }
+  if ((length != NULL) &&
+      length->value().IsSmi() &&
+      Smi::Cast(length->value()).Value() == expected_length) {
+    return NULL;  // Expected length matched.
+  }
+
+  return this;
+}
+
+
 Instruction* CheckSmiInstr::Canonicalize(FlowGraph* flow_graph) {
   return (value()->Type()->ToCid() == kSmiCid) ?  NULL : this;
 }
 
 
 Instruction* CheckEitherNonSmiInstr::Canonicalize(FlowGraph* flow_graph) {
   if ((left()->Type()->ToCid() == kDoubleCid) ||
       (right()->Type()->ToCid() == kDoubleCid)) {
     return NULL;  // Remove from the graph.
   }
@@ skipping 1436 matching lines @@
     case Token::kTRUNCDIV: return 0;
     case Token::kMOD: return 1;
     default: UNIMPLEMENTED(); return -1;
   }
 }
 
 
 #undef __
 
 }  // namespace dart