VM: Make precompiler process constants/fields only once, avoid using pool.InfoAt()

runtime/vm/object.h

Index: runtime/vm/object.h
diff --git a/runtime/vm/object.h b/runtime/vm/object.h
index 61a2866e27bbafd89d2dee7514b7633fd0217004..1dafbef4e9f0fbc2786bef845267bcc38fa74ae8 100644
--- a/runtime/vm/object.h
+++ b/runtime/vm/object.h
@@ -8655,6 +8655,26 @@ class UserTag : public Instance {
 };
 
 
+class ObjectPoolInfo {

[Florian Schneider, 2016/12/08 18:30:45]

: public ValueObject

[kustermann, 2016/12/08 19:14:38]

Done.

+ public:
+  explicit ObjectPoolInfo(const ObjectPool& pool)
+      : array_(TypedData::Handle(pool.info_array())) {}
+
+  explicit ObjectPoolInfo(const TypedData& info_array) : array_(info_array) {}

[Florian Schneider, 2016/12/08 18:30:45]

Not needed?

[kustermann, 2016/12/08 19:14:38]

See comment on call site. Using this constructor means one can re-use a
[TypedData] handle when looping over many different functions.

+
+  ObjectPool::EntryType InfoAt(intptr_t i) {
+    return static_cast<ObjectPool::EntryType>(array_.GetInt8(i));
+  }
+
+  void SetInfoAt(intptr_t i, ObjectPool::EntryType info) {
+    array_.SetInt8(i, static_cast<int8_t>(info));
+  }
+
+ private:
+  const TypedData& array_;
+};
+
+
 // Breaking cycles and loops.
 RawClass* Object::clazz() const {
   uword raw_value = reinterpret_cast<uword>(raw_);