VM: Improve receiver class check in polymorphic inlining.

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 77 matching lines @@
   }
   return AttributesEqual(other);
 }
 
 
 bool Value::Equals(Value* other) const {
   return definition() == other->definition();
 }
 
 
+static int LowestFirst(const intptr_t* a, const intptr_t* b) {
+  return *a - *b;
+}
+
+
 CheckClassInstr::CheckClassInstr(Value* value,
                                  intptr_t deopt_id,
                                  const ICData& unary_checks,
                                  intptr_t token_pos)
-    : unary_checks_(unary_checks), licm_hoisted_(false), token_pos_(token_pos) {
+    : unary_checks_(unary_checks),
+      cids_(unary_checks.NumberOfChecks()),
+      licm_hoisted_(false),
+      token_pos_(token_pos) {
   ASSERT(unary_checks.IsZoneHandle());
   // Expected useful check data.
   ASSERT(!unary_checks_.IsNull());
   ASSERT(unary_checks_.NumberOfChecks() > 0);
   ASSERT(unary_checks_.NumArgsTested() == 1);
   SetInputAt(0, value);
   deopt_id_ = deopt_id;
   // Otherwise use CheckSmiInstr.
   ASSERT((unary_checks_.NumberOfChecks() != 1) ||
          (unary_checks_.GetReceiverClassIdAt(0) != kSmiCid));
+  for (intptr_t i = 0; i < unary_checks.NumberOfChecks(); ++i) {
+    cids_.Add(unary_checks.GetReceiverClassIdAt(i));
+  }
+  cids_.Sort(LowestFirst);
 }
 
 
 bool CheckClassInstr::AttributesEqual(Instruction* other) const {
   CheckClassInstr* other_check = other->AsCheckClass();
   ASSERT(other_check != NULL);
   if (unary_checks().NumberOfChecks() !=
       other_check->unary_checks().NumberOfChecks()) {
     return false;
   }
@@ skipping 22 matching lines @@
     return false;
   }
   CompileType* in_type = value()->Type();
   const intptr_t cid = unary_checks().GetCidAt(0);
   // Performance check: use CheckSmiInstr instead.
   ASSERT(cid != kSmiCid);
   return in_type->is_nullable() && (in_type->ToNullableCid() == cid);
 }
 
 
+bool CheckClassInstr::IsDenseSwitch() const {
+  if (unary_checks().GetReceiverClassIdAt(0) == kSmiCid) return false;
+  if (cids_.length() > 2 &&
+      cids_[cids_.length() - 1] - cids_[0] < kBitsPerWord) {
+    return true;
+  }
+  return false;
+}
+
+
+intptr_t CheckClassInstr::ComputeCidMask() const {
+  ASSERT(IsDenseSwitch());
+  intptr_t mask = 0;
+  for (intptr_t i = 0; i < cids_.length(); ++i) {
+    mask |= 1 << (cids_[i] - cids_[0]);
+  }
+  return mask;
+}
+
+
+bool CheckClassInstr::IsDenseMask(intptr_t mask) {
+  // Returns true if the mask is a continuos sequence of ones in its binary
+  // representation (i.e. no holes)
+  return mask == -1 || Utils::IsPowerOfTwo(mask + 1);
+}
+
+
 bool LoadFieldInstr::IsUnboxedLoad() const {
   return FLAG_unbox_numeric_fields
       && (field() != NULL)
       && field()->IsUnboxedField();
 }
 
 
 bool LoadFieldInstr::IsPotentialUnboxedLoad() const {
   return FLAG_unbox_numeric_fields
       && (field() != NULL)
@@ skipping 3810 matching lines @@
     case Token::kTRUNCDIV: return 0;
     case Token::kMOD: return 1;
     default: UNIMPLEMENTED(); return -1;
   }
 }
 
 
 #undef __
 
 }  // namespace dart