8288098: [lworld] C2 fails to scalarize value class arguments

src/hotspot/share/oops/instanceKlass.cpp

@@ -166,16 +166,6 @@ static inline bool is_class_loader(const Symbol* class_name,
 
 bool InstanceKlass::field_is_null_free_inline_type(int index) const { return Signature::basic_type(field(index)->signature(constants())) == T_PRIMITIVE_OBJECT; }
 
-bool InstanceKlass::is_preload_class(Symbol* name) const {
-  for (int i = 0; i < _preload_classes->length(); i++) {
-    Symbol* class_name = _constants->klass_at_noresolve(_preload_classes->at(i));
-    if (class_name == name) {
-      return true;
-    }
-  }
-  return false;
-}
-
 // private: called to verify that k is a static member of this nest.
 // We know that k is an instance class in the same package and hence the
 // same classloader.

src/hotspot/share/oops/instanceKlass.hpp

@@ -550,7 +550,6 @@ class InstanceKlass: public Klass {
 
   Array<u2>* preload_classes() const { return _preload_classes; }
   void set_preload_classes(Array<u2>* c) { _preload_classes = c; }
-  bool is_preload_class(Symbol* name) const;
 
   // inner classes
   Array<u2>* inner_classes() const       { return _inner_classes; }

src/hotspot/share/runtime/sharedRuntime.cpp

@@ -2851,14 +2851,18 @@ AdapterHandlerEntry* AdapterHandlerLibrary::get_simple_adapter(const methodHandl
   if (total_args_passed == 0) {
     return _no_arg_handler;
   } else if (total_args_passed == 1) {
-    if (!method->is_static() && (!InlineTypePassFieldsAsArgs || !method->method_holder()->is_inline_klass())) {
+    if (!method->is_static()) {
+      if (InlineTypePassFieldsAsArgs && method->method_holder()->is_inline_klass()) {
+        return NULL;
+      }
       return _obj_arg_handler;
     }
     switch (method->signature()->char_at(1)) {
       case JVM_SIGNATURE_CLASS: {
         if (InlineTypePassFieldsAsArgs) {
           SignatureStream ss(method->signature());
-          if (method->method_holder()->is_preload_class(ss.as_symbol())) {
+          InlineKlass* vk = ss.as_inline_klass(method->method_holder());
+          if (vk != NULL) {
             return NULL;
           }
         }
@@ -2879,7 +2883,8 @@ AdapterHandlerEntry* AdapterHandlerLibrary::get_simple_adapter(const methodHandl
       case JVM_SIGNATURE_CLASS: {
         if (InlineTypePassFieldsAsArgs) {
           SignatureStream ss(method->signature());
-          if (method->method_holder()->is_preload_class(ss.as_symbol())) {
+          InlineKlass* vk = ss.as_inline_klass(method->method_holder());
+          if (vk != NULL) {
             return NULL;
           }
         }
@@ -2972,8 +2977,7 @@ void CompiledEntrySignature::compute_calling_conventions(bool init) {
       if (bt == T_OBJECT || bt == T_PRIMITIVE_OBJECT) {
         InlineKlass* vk = ss.as_inline_klass(holder);
         // TODO 8284443 Mismatch handling, we need to check parent method args (look at klassVtable::needs_new_vtable_entry)
-        if (vk != NULL && (bt == T_PRIMITIVE_OBJECT || holder->is_preload_class(vk->name())) &&
-            vk->can_be_passed_as_fields() && (init || _method->is_scalarized_arg(arg_num))) {
+        if (vk != NULL && vk->can_be_passed_as_fields() && (init || _method->is_scalarized_arg(arg_num))) {
           _num_inline_args++;
           has_scalarized = true;
           int last = _sig_cc->length();

test/hotspot/jtreg/compiler/valhalla/inlinetypes/MyValueClass1.java

@@ -172,4 +172,9 @@ static MyValueClass1 setV2(MyValueClass1 v, MyValueClass2 v2) {
     static MyValueClass1 setV4(MyValueClass1 v, MyValueClass2 v4) {
         return new MyValueClass1(v.x, v.y, v.z, v.o, v.oa, v.v1, v.v2, v4, v.c);
     }
+
+    @DontInline
+    void dontInline(MyValueClass1 arg) {
+
+    }
 }

test/hotspot/jtreg/compiler/valhalla/inlinetypes/TestNullableInlineTypes.java

@@ -2687,9 +2687,9 @@ public MyValue3.ref test97_helper3(boolean b) {
     // Same as test96 but with MyValue3 return
     @Test
     @IR(applyIf = {"InlineTypeReturnedAsFields", "true"},
-        failOn = {ALLOC_G})
+        counts = {ALLOC_G, " = 1"}) // 1 Object allocation
     @IR(applyIf = {"InlineTypeReturnedAsFields", "false"},
-        counts = {ALLOC_G, " = 1"})
+        counts = {ALLOC_G, " = 2"}) // 1 MyValue3 allocation + 1 Object allocation
     public MyValue3.ref test97(int c, boolean b) {
         MyValue3.ref res = null;
         if (c == 1) {

test/hotspot/jtreg/compiler/valhalla/inlinetypes/TestValueClasses.java

@@ -536,6 +536,7 @@ public MyValueClass1 test15(MyValueClass1 vt) {
         test15_helper1(vt);
         test15_helper2(vt);
         test15_helper3(vt);
+        vt.dontInline(vt);
         return res;
     }