Precompiler: Rehash types after reassigning class ids.

runtime/vm/precompiler.cc

Index: runtime/vm/precompiler.cc
diff --git a/runtime/vm/precompiler.cc b/runtime/vm/precompiler.cc
index 59af6d4d233845ac40c0973730cbfe8a0dec0fa6..a885508499a0f0c5e6eb391377c69b5f4d237261 100644
--- a/runtime/vm/precompiler.cc
+++ b/runtime/vm/precompiler.cc
@@ -2553,6 +2553,7 @@ void Precompiler::SortClasses() {
 
   RemapClassIds(old_to_new_cid);
   delete[] old_to_new_cid;
+  RehashTypes();  // Types use cid's as part of their hashes.
 }
 
 
@@ -2627,6 +2628,101 @@ void Precompiler::RemapClassIds(intptr_t* old_to_new_cid) {
 }
 
 
+class ClearTypeHashVisitor : public ObjectVisitor {
+ public:
+  explicit ClearTypeHashVisitor(Zone* zone)
+      : type_param_(TypeParameter::Handle(zone)),
+        type_(Type::Handle(zone)),
+        type_args_(TypeArguments::Handle(zone)),
+        bounded_type_(BoundedType::Handle(zone)) {}
+
+  void VisitObject(RawObject* obj) {
+    if (obj->IsTypeParameter()) {
+      type_param_ ^= obj;
+      type_param_.SetHash(0);
+    } else if (obj->IsType()) {
+      type_ ^= obj;
+      type_.SetHash(0);
+    } else if (obj->IsBoundedType()) {
+      bounded_type_ ^= obj;
+      bounded_type_.SetHash(0);
+    } else if (obj->IsTypeArguments()) {
+      type_args_ ^= obj;
+      type_args_.SetHash(0);
+    }

[siva, 2017/01/20 18:37:02]

Should we also be clearing the hash value for IsMixinAppType() ?

[regis, 2017/01/20 19:21:59]

As soon as the super type of a class is resolved, the MixinAppType is replaced
by a set of synthesized mixin application classes. A MixinAppType should never
be seen while snapshotting (unless we snapshot still unresolved classes). In any
case, they do not cash or even compute their hash.

[rmacnak, 2017/01/20 20:13:12]

Removed hash_ from RawMixinAppType

+  }
+
+ private:
+  TypeParameter& type_param_;
+  Type& type_;
+  TypeArguments& type_args_;
+  BoundedType& bounded_type_;
+};
+
+
+void Precompiler::RehashTypes() {
+  // Clear all cached hash values.
+  {
+    HeapIterationScope his;
+    ClearTypeHashVisitor visitor(Z);
+    I->heap()->VisitObjects(&visitor);
+  }
+
+  // Rehash the canonical Types table.
+  ObjectStore* object_store = I->object_store();
+  GrowableObjectArray& types =
+      GrowableObjectArray::Handle(Z, GrowableObjectArray::New());
+  Array& types_array = Array::Handle(Z);
+  Type& type = Type::Handle(Z);
+  {
+    CanonicalTypeSet types_table(Z, object_store->canonical_types());
+    types_array = HashTables::ToArray(types_table, false);
+    for (intptr_t i = 0; i < (types_array.Length() - 1); i++) {
+      type ^= types_array.At(i);
+      types.Add(type);
+    }
+    types_table.Release();
+  }
+
+  intptr_t dict_size = Utils::RoundUpToPowerOfTwo(types.Length() * 4 / 3);
+  types_array = HashTables::New<CanonicalTypeSet>(dict_size, Heap::kOld);
+  CanonicalTypeSet types_table(Z, types_array.raw());
+  for (intptr_t i = 0; i < types.Length(); i++) {
+    type ^= types.At(i);
+    bool present = types_table.Insert(type);
+    ASSERT(!present);
+  }
+  object_store->set_canonical_types(types_table.Release());
+
+  // Rehash the canonical TypeArguments table.
+  Array& typeargs_array = Array::Handle(Z);
+  GrowableObjectArray& typeargs =
+      GrowableObjectArray::Handle(Z, GrowableObjectArray::New());
+  TypeArguments& typearg = TypeArguments::Handle(Z);
+  {
+    CanonicalTypeArgumentsSet typeargs_table(
+        Z, object_store->canonical_type_arguments());
+    typeargs_array = HashTables::ToArray(typeargs_table, false);
+    for (intptr_t i = 0; i < (typeargs_array.Length() - 1); i++) {
+      typearg ^= typeargs_array.At(i);
+      typeargs.Add(typearg);
+    }
+    typeargs_table.Release();
+  }
+
+  dict_size = Utils::RoundUpToPowerOfTwo(typeargs.Length() * 4 / 3);
+  typeargs_array =
+      HashTables::New<CanonicalTypeArgumentsSet>(dict_size, Heap::kOld);
+  CanonicalTypeArgumentsSet typeargs_table(Z, typeargs_array.raw());
+  for (intptr_t i = 0; i < typeargs.Length(); i++) {
+    typearg ^= typeargs.At(i);
+    bool present = typeargs_table.Insert(typearg);
+    ASSERT(!present);
+  }
+  object_store->set_canonical_type_arguments(typeargs_table.Release());
+}
+
+
 void Precompiler::VerifyJITFeedback() {
   if (jit_feedback_ == NULL) return;