In precompilation, finalize all classes eagerly. Use the stable class hierarchy for doing CHA based…

runtime/vm/precompiler.cc

Index: runtime/vm/precompiler.cc
diff --git a/runtime/vm/precompiler.cc b/runtime/vm/precompiler.cc
index f061da02c6905080a973bca7316e9dec985b45da..7000601bc549cc3da0aa236ab80d47122d4d798b 100644
--- a/runtime/vm/precompiler.cc
+++ b/runtime/vm/precompiler.cc
@@ -17,6 +17,7 @@
 namespace dart {
 
 
+#define T (thread())
 #define I (isolate())
 #define Z (zone())
 
@@ -73,6 +74,10 @@ void Precompiler::DoCompileAll(
   // that we have already looked for the function's callees.
   ClearAllCode();
 
+  // Make sure class hierarchy is stable before compilation so that CHA
+  // can be used.
+  FinalizeAllClasses();
+
   // Start with the allocations and invocations that happen from C++.
   AddRoots(embedder_entry_points);
 
@@ -824,4 +829,24 @@ void Precompiler::VisitFunctions(FunctionVisitor* visitor) {
   }
 }
 
+
+void Precompiler::FinalizeAllClasses() {
+  Library& lib = Library::Handle(Z);
+  Class& cls = Class::Handle(Z);
+
+  for (intptr_t i = 0; i < libraries_.Length(); i++) {
+    lib ^= libraries_.At(i);
+    ClassDictionaryIterator it(lib, ClassDictionaryIterator::kIteratePrivate);
+    while (it.HasNext()) {
+      cls = it.GetNextClass();
+      if (cls.IsDynamicClass()) {
+        continue;  // class 'dynamic' is in the read-only VM isolate.
+      }
+      cls.EnsureIsFinalized(T);
+    }
+  }
+  I->set_all_classes_finalized(true);
+}
+
+
 }  // namespace dart