[strong] Implement strong mode restrictions on property access

src/ic/ic.cc

Index: src/ic/ic.cc
diff --git a/src/ic/ic.cc b/src/ic/ic.cc
index e8be95ba34a5e9d17a89d2ab76b692b2ebc16f91..93843204949ad2117fb31ff69036c71399170a02 100644
--- a/src/ic/ic.cc
+++ b/src/ic/ic.cc
@@ -571,11 +571,14 @@ void CompareIC::Clear(Isolate* isolate, Address address, Code* target,
 
 
 // static
-Handle<Code> KeyedLoadIC::ChooseMegamorphicStub(Isolate* isolate) {
+Handle<Code> KeyedLoadIC::ChooseMegamorphicStub(Isolate* isolate,
+                                                ExtraICState extra_state) {
   if (FLAG_compiled_keyed_generic_loads) {
-    return KeyedLoadGenericStub(isolate).GetCode();
+    return KeyedLoadGenericStub(isolate, LoadICState(extra_state)).GetCode();
   } else {
-    return isolate->builtins()->KeyedLoadIC_Megamorphic();
+    return is_strong(LoadICState::GetStrength(extra_state))
+               ? isolate->builtins()->KeyedLoadIC_Megamorphic_Strong()
+               : isolate->builtins()->KeyedLoadIC_Megamorphic();
   }
 }
 
@@ -679,7 +682,8 @@ MaybeHandle<Object> LoadIC::Load(Handle<Object> object, Handle<Name> name) {
     Handle<Object> result;
     ASSIGN_RETURN_ON_EXCEPTION(
         isolate(), result,
-        Runtime::GetElementOrCharAt(isolate(), object, index), Object);
+        Runtime::GetElementOrCharAt(isolate(), object, index, strength()),
+        Object);
     return result;
   }
 
@@ -722,8 +726,9 @@ MaybeHandle<Object> LoadIC::Load(Handle<Object> object, Handle<Name> name) {
 
     // Get the property.
     Handle<Object> result;
-    ASSIGN_RETURN_ON_EXCEPTION(isolate(), result, Object::GetProperty(&it),
-                               Object);
+
+    ASSIGN_RETURN_ON_EXCEPTION(isolate(), result,
+                               Object::GetProperty(&it, strength()), Object);
     if (it.IsFound()) {
       return result;
     } else if (!IsUndeclaredGlobal(object)) {
@@ -915,21 +920,25 @@ Handle<Code> LoadIC::initialize_stub_in_optimized_code(
 }
 
 
-Handle<Code> KeyedLoadIC::initialize_stub(Isolate* isolate) {
-  return KeyedLoadICTrampolineStub(isolate).GetCode();
+Handle<Code> KeyedLoadIC::initialize_stub(Isolate* isolate,
+                                          ExtraICState extra_state) {
+  return KeyedLoadICTrampolineStub(isolate, LoadICState(extra_state)).GetCode();
 }
 
 
 Handle<Code> KeyedLoadIC::initialize_stub_in_optimized_code(
-    Isolate* isolate, State initialization_state) {
+    Isolate* isolate, State initialization_state, ExtraICState extra_state) {
   if (initialization_state != MEGAMORPHIC) {
-    return KeyedLoadICStub(isolate).GetCode();
+    return KeyedLoadICStub(isolate, LoadICState(extra_state)).GetCode();
   }
+  bool strong = is_strong(LoadICState::GetStrength(extra_state));
   switch (initialization_state) {
     case UNINITIALIZED:
-      return isolate->builtins()->KeyedLoadIC_Initialize();
+      return strong ? isolate->builtins()->KeyedLoadIC_Initialize_Strong()

[mvstanton, 2015/06/09 12:46:44]

I think this shows some unfinished clean-up work now that vector ics area always
on for loads. We can't achieve UNINITIALIZED state here because of the statement
above ("if (initialization_state != MEGAMORPHIC)").

Suggests that you could eliminate KeyedLoadIC_Initialize() from the builtins,
and your strong variant then too.

[conradw, 2015/06/09 13:09:27]

Done.

+                    : isolate->builtins()->KeyedLoadIC_Initialize();
     case MEGAMORPHIC:
-      return isolate->builtins()->KeyedLoadIC_Megamorphic();
+      return strong ? isolate->builtins()->KeyedLoadIC_Megamorphic_Strong()
+                    : isolate->builtins()->KeyedLoadIC_Megamorphic();
     default:
       UNREACHABLE();
   }
@@ -962,7 +971,7 @@ Handle<Code> KeyedStoreIC::initialize_stub(Isolate* isolate,
 
 Handle<Code> LoadIC::megamorphic_stub() {
   DCHECK_EQ(Code::KEYED_LOAD_IC, kind());
-  return KeyedLoadIC::ChooseMegamorphicStub(isolate());
+  return KeyedLoadIC::ChooseMegamorphicStub(isolate(), extra_ic_state());
 }
 
 
@@ -986,7 +995,7 @@ void LoadIC::UpdateCaches(LookupIterator* lookup) {
       lookup->state() == LookupIterator::ACCESS_CHECK) {
     code = slow_stub();
   } else if (!lookup->IsFound()) {
-    if (kind() == Code::LOAD_IC) {
+    if (kind() == Code::LOAD_IC && !is_strong(strength())) {
       code = NamedLoadHandlerCompiler::ComputeLoadNonexistent(lookup->name(),
                                                               receiver_map());
       // TODO(jkummerow/verwaest): Introduce a builtin that handles this case.
@@ -1245,7 +1254,8 @@ Handle<Code> KeyedLoadIC::LoadElementStub(Handle<HeapObject> receiver) {
 
   if (target_receiver_maps.length() == 0) {
     Handle<Code> handler =
-        PropertyICCompiler::ComputeKeyedLoadMonomorphicHandler(receiver_map);
+        PropertyICCompiler::ComputeKeyedLoadMonomorphicHandler(
+            receiver_map, extra_ic_state());
     ConfigureVectorState(Handle<Name>::null(), receiver_map, handler);
     return null_handle;
   }
@@ -1262,7 +1272,8 @@ Handle<Code> KeyedLoadIC::LoadElementStub(Handle<HeapObject> receiver) {
           target_receiver_maps.at(0)->elements_kind(),
           Handle<JSObject>::cast(receiver)->GetElementsKind())) {
     Handle<Code> handler =
-        PropertyICCompiler::ComputeKeyedLoadMonomorphicHandler(receiver_map);
+        PropertyICCompiler::ComputeKeyedLoadMonomorphicHandler(
+            receiver_map, extra_ic_state());
     ConfigureVectorState(Handle<Name>::null(), receiver_map, handler);
     return null_handle;
   }
@@ -1287,7 +1298,7 @@ Handle<Code> KeyedLoadIC::LoadElementStub(Handle<HeapObject> receiver) {
 
   CodeHandleList handlers(target_receiver_maps.length());
   ElementHandlerCompiler compiler(isolate());
-  compiler.CompileElementHandlers(&target_receiver_maps, &handlers);
+  compiler.CompileElementHandlers(&target_receiver_maps, &handlers, strength());
   ConfigureVectorState(Handle<Name>::null(), &target_receiver_maps, &handlers);
   return null_handle;
 }
@@ -1298,8 +1309,8 @@ MaybeHandle<Object> KeyedLoadIC::Load(Handle<Object> object,
   if (MigrateDeprecated(object)) {
     Handle<Object> result;
     ASSIGN_RETURN_ON_EXCEPTION(
-        isolate(), result, Runtime::GetObjectProperty(isolate(), object, key),
-        Object);
+        isolate(), result,
+        Runtime::GetObjectProperty(isolate(), object, key, strength()), Object);
     return result;
   }
 
@@ -1346,10 +1357,11 @@ MaybeHandle<Object> KeyedLoadIC::Load(Handle<Object> object,
   }
 
   if (!load_handle.is_null()) return load_handle;
+
   Handle<Object> result;
-  ASSIGN_RETURN_ON_EXCEPTION(isolate(), result,
-                             Runtime::GetObjectProperty(isolate(), object, key),
-                             Object);
+  ASSIGN_RETURN_ON_EXCEPTION(
+      isolate(), result,
+      Runtime::GetObjectProperty(isolate(), object, key, strength()), Object);
   return result;
 }
 
@@ -2812,6 +2824,7 @@ RUNTIME_FUNCTION(LoadPropertyWithInterceptor) {
 
   Handle<Object> result;
   LookupIterator it(receiver, name, holder);
+  // TODO(conradw): Investigate strong mode semantics for this.
   ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, result,
                                      JSObject::GetProperty(&it));
 
@@ -2857,8 +2870,10 @@ RUNTIME_FUNCTION(LoadElementWithInterceptor) {
   DCHECK(args.smi_at(1) >= 0);
   uint32_t index = args.smi_at(1);
   Handle<Object> result;
+  // TODO(conradw): Investigate strong mode semantics for this.
+  Strength strength = Strength::WEAK;
   ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
-      isolate, result, Object::GetElement(isolate, receiver, index));
+      isolate, result, Object::GetElement(isolate, receiver, index, strength));
   return *result;
 }
 
@@ -2894,6 +2909,36 @@ RUNTIME_FUNCTION(LoadIC_MissFromStubFailure) {
 }
 
 
+RUNTIME_FUNCTION(LoadIC_Slow) {
+  HandleScope scope(isolate);
+  DCHECK(args.length() == 2);
+
+  Handle<Object> receiver = args.at<Object>(0);
+  Handle<Name> name = args.at<Name>(1);
+  LoadIC ic(IC::NO_EXTRA_FRAME, isolate, true);
+  Handle<Object> result;
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+      isolate, result,
+      Runtime::GetObjectProperty(isolate, receiver, name, ic.strength()));
+  return *result;
+}
+
+
+RUNTIME_FUNCTION(KeyedLoadIC_Slow) {
+  HandleScope scope(isolate);
+  DCHECK(args.length() == 2);
+
+  Handle<Object> receiver = args.at<Object>(0);
+  Handle<Object> key = args.at<Object>(1);
+  LoadIC ic(IC::NO_EXTRA_FRAME, isolate, true);
+  Handle<Object> result;
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+      isolate, result,
+      Runtime::KeyedGetObjectProperty(isolate, receiver, key, ic.strength()));
+  return *result;
+}
+
+
 static const Address IC_utilities[] = {
 #define ADDR(name) FUNCTION_ADDR(name),
     IC_UTIL_LIST(ADDR) NULL
@@ -2902,5 +2947,5 @@ static const Address IC_utilities[] = {
 
 
 Address IC::AddressFromUtilityId(IC::UtilityId id) { return IC_utilities[id]; }
-}  // namespace internal
-}  // namespace v8
+}
+}  // namespace v8::internal