[turbofan] Collect invocation counts and compute relative call frequencies.

src/type-feedback-vector-inl.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_TYPE_FEEDBACK_VECTOR_INL_H_
 #define V8_TYPE_FEEDBACK_VECTOR_INL_H_
 
 #include "src/type-feedback-vector.h"
 
 namespace v8 {
@@ skipping 59 matching lines @@
       return false;
 
     case FeedbackVectorSlotKind::KINDS_NUMBER:
       break;
   }
   UNREACHABLE();
   return false;
 }
 
 bool TypeFeedbackVector::is_empty() const {
-  if (length() == 0) return true;
-  DCHECK(length() > kReservedIndexCount);
-  return false;
+  return length() == kReservedIndexCount;
 }
 
-
 int TypeFeedbackVector::slot_count() const {
-  if (length() == 0) return 0;
-  DCHECK(length() > kReservedIndexCount);
   return length() - kReservedIndexCount;
 }
 
 
 TypeFeedbackMetadata* TypeFeedbackVector::metadata() const {
-  return is_empty() ? TypeFeedbackMetadata::cast(GetHeap()->empty_fixed_array())
-                    : TypeFeedbackMetadata::cast(get(kMetadataIndex));
+  return TypeFeedbackMetadata::cast(get(kMetadataIndex));
+}
+
+int TypeFeedbackVector::invocation_count() const {
+  return Smi::cast(get(kInvocationCountIndex))->value();
 }
 
 // Conversion from an integer index to either a slot or an ic slot.
 // static
 FeedbackVectorSlot TypeFeedbackVector::ToSlot(int index) {
   DCHECK(index >= kReservedIndexCount);
   return FeedbackVectorSlot(index - kReservedIndexCount);
 }
 
 
@@ skipping 94 matching lines @@
   int index = vector()->GetIndex(slot()) + 1;
   vector()->set(index, feedback_extra, mode);
 }
 
 
 Isolate* FeedbackNexus::GetIsolate() const { return vector()->GetIsolate(); }
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TYPE_FEEDBACK_VECTOR_INL_H_