8287223: C1: Inlining attempt through MH::invokeBasic() with null receiver

Reviewed-by: kvn

src/hotspot/share/c1/c1_GraphBuilder.cpp

@@ -4145,20 +4145,28 @@ bool GraphBuilder::try_method_handle_inline(ciMethod* callee, bool ignore_return
       const int args_base = state()->stack_size() - callee->arg_size();
       ValueType* type = state()->stack_at(args_base)->type();
       if (type->is_constant()) {
-        ciMethod* target = type->as_ObjectType()->constant_value()->as_method_handle()->get_vmtarget();
-        // We don't do CHA here so only inline static and statically bindable methods.
-        if (target->is_static() || target->can_be_statically_bound()) {
-          if (ciMethod::is_consistent_info(callee, target)) {
-            Bytecodes::Code bc = target->is_static() ? Bytecodes::_invokestatic : Bytecodes::_invokevirtual;
-            ignore_return = ignore_return || (callee->return_type()->is_void() && !target->return_type()->is_void());
-            if (try_inline(target, /*holder_known*/ !callee->is_static(), ignore_return, bc)) {
-              return true;
+        ciObject* mh = type->as_ObjectType()->constant_value();
+        if (mh->is_method_handle()) {
+          ciMethod* target = mh->as_method_handle()->get_vmtarget();
+
+          // We don't do CHA here so only inline static and statically bindable methods.
+          if (target->is_static() || target->can_be_statically_bound()) {
+            if (ciMethod::is_consistent_info(callee, target)) {
+              Bytecodes::Code bc = target->is_static() ? Bytecodes::_invokestatic : Bytecodes::_invokevirtual;
+              ignore_return = ignore_return || (callee->return_type()->is_void() && !target->return_type()->is_void());
+              if (try_inline(target, /*holder_known*/ !callee->is_static(), ignore_return, bc)) {
+                return true;
+              }
+            } else {
+              print_inlining(target, "signatures mismatch", /*success*/ false);
             }
           } else {
-            print_inlining(target, "signatures mismatch", /*success*/ false);
+            assert(false, "no inlining through MH::invokeBasic"); // missing optimization opportunity due to suboptimal LF shape
+            print_inlining(target, "not static or statically bindable", /*success*/ false);
           }
         } else {
-          print_inlining(target, "not static or statically bindable", /*success*/ false);
+          assert(mh->is_null_object(), "not a null");
+          print_inlining(callee, "receiver is always null", /*success*/ false);
         }
       } else {
         print_inlining(callee, "receiver not constant", /*success*/ false);

src/hotspot/share/opto/callGenerator.cpp

@@ -1018,22 +1018,29 @@ CallGenerator* CallGenerator::for_method_handle_inline(JVMState* jvms, ciMethod*
       Node* receiver = kit.argument(0);
       if (receiver->Opcode() == Op_ConP) {
         input_not_const = false;
-        const TypeOopPtr* oop_ptr = receiver->bottom_type()->is_oopptr();
-        ciMethod* target = oop_ptr->const_oop()->as_method_handle()->get_vmtarget();
-        const int vtable_index = Method::invalid_vtable_index;
+        const TypeOopPtr* recv_toop = receiver->bottom_type()->isa_oopptr();
+        if (recv_toop != NULL) {
+          ciMethod* target = recv_toop->const_oop()->as_method_handle()->get_vmtarget();
+          const int vtable_index = Method::invalid_vtable_index;
 
-        if (!ciMethod::is_consistent_info(callee, target)) {
+          if (!ciMethod::is_consistent_info(callee, target)) {
+            print_inlining_failure(C, callee, jvms->depth() - 1, jvms->bci(),
+                                   "signatures mismatch");
+            return NULL;
+          }
+
+          CallGenerator *cg = C->call_generator(target, vtable_index,
+                                                false /* call_does_dispatch */,
+                                                jvms,
+                                                allow_inline,
+                                                PROB_ALWAYS);
+          return cg;
+        } else {
+          assert(receiver->bottom_type() == TypePtr::NULL_PTR, "not a null: %s",
+                 Type::str(receiver->bottom_type()));
           print_inlining_failure(C, callee, jvms->depth() - 1, jvms->bci(),
-                                 "signatures mismatch");
-          return NULL;
+                                 "receiver is always null");
         }
-
-        CallGenerator* cg = C->call_generator(target, vtable_index,
-                                              false /* call_does_dispatch */,
-                                              jvms,
-                                              allow_inline,
-                                              PROB_ALWAYS);
-        return cg;
       } else {
         print_inlining_failure(C, callee, jvms->depth() - 1, jvms->bci(),
                                "receiver not constant");

test/hotspot/jtreg/compiler/jsr292/NullConstantMHReceiver.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * @test
+ * @bug 8287223
+ * @library /test/lib / patches
+ *
+ * @build java.base/java.lang.invoke.MethodHandleHelper
+ * @run main/bootclasspath/othervm -Xbatch -XX:CompileCommand=compileonly,*::test -XX:-TieredCompilation                         compiler.jsr292.NullConstantMHReceiver
+ * @run main/bootclasspath/othervm -Xbatch -XX:CompileCommand=compileonly,*::test -XX:+TieredCompilation -XX:TieredStopAtLevel=1 compiler.jsr292.NullConstantMHReceiver
+ */
+
+package compiler.jsr292;
+
+import java.lang.invoke.MethodHandleHelper;
+
+public class NullConstantMHReceiver {
+    static void test() throws Throwable {
+        MethodHandleHelper.invokeBasicL(null);
+    }
+
+    public static void main(String[] args) throws Throwable {
+        for (int i = 0; i < 15000; i++) {
+            try {
+                test();
+            } catch (NullPointerException e) {
+                // expected
+                continue;
+            }
+            throw new AssertionError("NPE wasn't thrown");
+        }
+        System.out.println("TEST PASSED");
+    }
+}