Rehash canonical constants table for each class that can be affected by the 'become' operation

runtime/vm/isolate_reload.cc

Index: runtime/vm/isolate_reload.cc
diff --git a/runtime/vm/isolate_reload.cc b/runtime/vm/isolate_reload.cc
index 4370ab183970ca74b93c649e8a0f3d2361cca742..2e8ea6bd0ef38c0ad8b0243672ccf94589f18fc4 100644
--- a/runtime/vm/isolate_reload.cc
+++ b/runtime/vm/isolate_reload.cc
@@ -1156,21 +1156,8 @@ void IsolateReloadContext::Commit() {
     }
   }
 
-  // Rehash constants map for all new classes and the closure class.
-  Class& cls = Class::Handle(zone_);
-  cls = I->class_table()->At(kClosureCid);
-  cls.RehashConstants(zone_);
-  {
-    ASSERT(class_map_storage_ != Array::null());
-    UnorderedHashMap<ClassMapTraits> map(class_map_storage_);
-    UnorderedHashMap<ClassMapTraits>::Iterator it(&map);
-    while (it.MoveNext()) {
-      const intptr_t entry = it.Current();
-      cls = Class::RawCast(map.GetKey(entry));
-      cls.RehashConstants(zone_);
-    }
-    map.Release();
-  }
+  // Rehash constants map for all classes.
+  RehashConstants();
 
 #ifdef DEBUG
   // Verify that all canonical instances are correctly setup in the
@@ -1183,6 +1170,27 @@ void IsolateReloadContext::Commit() {
 }
 
 
+void IsolateReloadContext::RehashConstants() {
+  ClassTable* class_table = I->class_table();
+  Class& cls = Class::Handle(zone_);
+  const intptr_t top = class_table->NumCids();
+  for (intptr_t cid = kInstanceCid; cid < top; cid++) {

[siva, 2016/11/15 22:58:22]

Should this be (kNumPredefinedCids + 1)

[rmacnak, 2016/11/15 23:13:33]

No, we still need to rehash array, growable array, map, etc.

+    if (!class_table->IsValidIndex(cid) || !class_table->HasValidClassAt(cid)) {

[siva, 2016/11/15 22:58:22]

IsValidIndex(cid) is implicit right with the check above,

maybe just

ASSERT(class_table->IsValidIndex(cid));

+      // Skip invalid classes.
+      continue;
+    }
+    if (RawObject::IsNumberClassId(cid) || RawObject::IsStringClassId(cid)) {
+      // Skip classes that cannot be affected by the 'become' operation.
+      continue;
+    }

[siva, 2016/11/15 22:58:22]

By running from kNumPredefinedCids this check for number and string woul
not be needed.

+    // Rehash constants.
+    cls = class_table->At(cid);
+    VTIR_Print("Rehashing constants in class `%s`\n", cls.ToCString());
+    cls.RehashConstants(zone_);
+  }
+}
+
+
 bool IsolateReloadContext::IsDirty(const Library& lib) {
   const intptr_t index = lib.index();
   if (index == static_cast<classid_t>(-1)) {