8352696: JFR: assert(false): EA: missing memory path

Reviewed-by: thartmann, shade, kvn

Author: Markus Grönlund

src/hotspot/share/opto/library_call.cpp

@@ -3154,7 +3154,8 @@ bool LibraryCallKit::inline_native_jvm_commit() {
   set_control(is_notified);
 
   // Reset notified state.
-  Node* notified_reset_memory = store_to_memory(control(), notified_offset, _gvn.intcon(0), T_BOOLEAN, MemNode::unordered);
+  store_to_memory(control(), notified_offset, _gvn.intcon(0), T_BOOLEAN, MemNode::unordered);
+  Node* notified_reset_memory = reset_memory();
 
   // Iff notified, the return address of the commit method is the current position of the backing java buffer. This is used to reset the event writer.
   Node* current_pos_X = _gvn.transform(new LoadXNode(control(), input_memory_state, java_buffer_pos_offset, TypeRawPtr::NOTNULL, TypeX_X, MemNode::unordered));
@@ -3172,12 +3173,10 @@ bool LibraryCallKit::inline_native_jvm_commit() {
   Node* next_pos_X = _gvn.transform(ConvL2X(arg));
 
   // Store the next_position to the underlying jfr java buffer.
-  Node* commit_memory;
-#ifdef _LP64
-  commit_memory = store_to_memory(control(), java_buffer_pos_offset, next_pos_X, T_LONG, MemNode::release);
-#else
-  commit_memory = store_to_memory(control(), java_buffer_pos_offset, next_pos_X, T_INT, MemNode::release);
-#endif
+  store_to_memory(control(), java_buffer_pos_offset, next_pos_X, LP64_ONLY(T_LONG) NOT_LP64(T_INT), MemNode::release);
+
+  Node* commit_memory = reset_memory();
+  set_all_memory(commit_memory);
 
   // Now load the flags from off the java buffer and decide if the buffer is a lease. If so, it needs to be returned post-commit.
   Node* java_buffer_flags_offset = _gvn.transform(new AddPNode(top(), java_buffer, _gvn.transform(MakeConX(in_bytes(JFR_BUFFER_FLAGS_OFFSET)))));

test/jdk/jdk/jfr/jvm/TestJvmCommitIntrinsicAndEA.java

@@ -0,0 +1,93 @@
+/*
+ * Copyright (c) 2025, 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.
+ */
+
+package jdk.jfr.jvm;
+
+import java.util.concurrent.Executor;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ThreadFactory;
+import java.util.concurrent.CountDownLatch;
+import jdk.jfr.consumer.RecordingStream;
+import jdk.test.lib.jfr.EventNames;
+
+/**
+ *
+ * A successful execution is when the JTREG test executes successfully,
+ * i.e., with no exceptions or JVM asserts.
+ *
+ * In JVM debug builds, C2 will assert as part of EscapeAnalysis and dump an hs_err<pid>.log:
+ *
+ * #
+ * # A fatal error has been detected by the Java Runtime Environment:
+ * #
+ * # Internal Error (..\open\src\hotspot\share\opto\escape.cpp:4788)
+ * # assert(false) failed: EA: missing memory path
+ *
+ * Current thread JavaThread "C2 CompilerThread2"
+ * Current CompileTask:
+ * C2:27036 1966 ! 4   java.lang.VirtualThread::run (173 bytes)
+ *
+ * ConnectionGraph::split_unique_types+0x2409 (escape.cpp:4788)
+ * ConnectionGraph::compute_escape+0x11e6 (escape.cpp:397)
+ * ConnectionGraph::do_analysis+0xf2 (escape.cpp:118)
+ * Compile::Optimize+0x85d (compile.cpp:2381)
+ * ...
+ *
+ * The error is because C2's Escape Analysis does not recognize a pattern
+ * where one input of memory Phi node is MergeMem node, and another is RAW store.
+ * This pattern is created by the jdk.jfr.internal.JVM.commit() intrinsic,
+ * which is inlined because of inlining the JFR event jdk.VirtualThreadStart.
+ *
+ * As a result, EA complains about a strange memory graph.
+ */
+
+/**
+ * @test
+ * @bug 8352696
+ * @requires vm.flagless & vm.hasJFR & vm.debug
+ * @library /test/lib /test/jdk
+ * @run main/othervm -Xbatch jdk.jfr.jvm.TestJvmCommitIntrinsicAndEA
+ */
+public final class TestJvmCommitIntrinsicAndEA {
+    private static final int NUM_TASKS = 10_000;
+
+    public static void main(String[] args) throws Throwable {
+        CountDownLatch latch = new CountDownLatch(NUM_TASKS);
+
+        try (RecordingStream rs = new RecordingStream()) {
+            rs.enable(EventNames.VirtualThreadStart).withoutStackTrace();
+            rs.enable(EventNames.VirtualThreadEnd).withoutStackTrace();
+            rs.onEvent(EventNames.VirtualThreadEnd, e -> latch.countDown());
+            rs.startAsync();
+            // Execute NUM_TASKS, each in their own virtual thread.
+            ThreadFactory factory = Thread.ofVirtual().factory();
+            try (var executor = Executors.newThreadPerTaskExecutor(factory)) {
+                for (int i = 0; i < NUM_TASKS; i++) {
+                    executor.submit(() -> { });
+                }
+            }
+            latch.await();
+        }
+    }
+}