8330153: C2: dump barrier information for all Mach nodes

Reviewed-by: kvn, thartmann

src/hotspot/share/opto/machnode.cpp

@@ -548,6 +548,11 @@ void MachNode::dump_spec(outputStream *st) const {
     if( C->alias_type(t)->is_volatile() )
       st->print(" Volatile!");
   }
+  if (barrier_data() != 0) {
+    st->print(" barrier(");
+    BarrierSet::barrier_set()->barrier_set_c2()->dump_barrier_data(this, st);
+    st->print(") ");
+  }
 }
 
 //------------------------------dump_format------------------------------------
@@ -560,16 +565,12 @@ void MachNode::dump_format(PhaseRegAlloc *ra, outputStream *st) const {
 //=============================================================================
 #ifndef PRODUCT
 void MachTypeNode::dump_spec(outputStream *st) const {
+  MachNode::dump_spec(st);
   if (_bottom_type != nullptr) {
     _bottom_type->dump_on(st);
   } else {
     st->print(" null");
   }
-  if (barrier_data() != 0) {
-    st->print(" barrier(");
-    BarrierSet::barrier_set()->barrier_set_c2()->dump_barrier_data(this, st);
-    st->print(")");
-  }
 }
 #endif
 

test/hotspot/jtreg/compiler/lib/ir_framework/IRNode.java

@@ -2076,6 +2076,12 @@ public class IRNode {
         machOnly(Z_STORE_P_WITH_BARRIER_FLAG, regex);
     }
 
+    public static final String Z_COMPARE_AND_SWAP_P_WITH_BARRIER_FLAG = COMPOSITE_PREFIX + "Z_COMPARE_AND_SWAP_P_WITH_BARRIER_FLAG" + POSTFIX;
+    static {
+        String regex = START + "zCompareAndSwapP" + MID + "barrier\\(\\s*" + IS_REPLACED + "\\s*\\)" + END;
+        machOnly(Z_COMPARE_AND_SWAP_P_WITH_BARRIER_FLAG, regex);
+    }
+
     public static final String Z_GET_AND_SET_P_WITH_BARRIER_FLAG = COMPOSITE_PREFIX + "Z_GET_AND_SET_P_WITH_BARRIER_FLAG" + POSTFIX;
     static {
         String regex = START + "(zXChgP)|(zGetAndSetP\\S*)" + MID + "barrier\\(\\s*" + IS_REPLACED + "\\s*\\)" + END;

test/hotspot/jtreg/testlibrary_tests/ir_framework/examples/GCBarrierIRExample.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright (c) 2024, 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 ir_framework.examples;
+
+import compiler.lib.ir_framework.*;
+import java.lang.invoke.VarHandle;
+import java.lang.invoke.MethodHandles;
+
+/**
+ * @test
+ * @bug 8330153
+ * @summary Example test that illustrates the use of the IR test framework for
+ *          verification of late-expanded GC barriers.
+ * @library /test/lib /
+ * @run driver ir_framework.examples.GCBarrierIRExample
+ */
+
+public class GCBarrierIRExample {
+
+    static class Outer {
+        Object f;
+    }
+
+    static final VarHandle fVarHandle;
+    static {
+        MethodHandles.Lookup l = MethodHandles.lookup();
+        try {
+            fVarHandle = l.findVarHandle(Outer.class, "f", Object.class);
+        } catch (Exception e) {
+            throw new Error(e);
+        }
+    }
+    static Outer o = new Outer();
+    static Object oldVal = new Object();
+    static Object newVal = new Object();
+
+    public static void main(String[] args) {
+        // These rules apply only to collectors that expand barriers at code
+        // emission, such as ZGC. Because the collector selection flags are not
+        // whitelisted (see IR framework's README.md file), the user (as opposed
+        // to jtreg) needs to set these flags here.
+        TestFramework.runWithFlags("-XX:+UseZGC", "-XX:+ZGenerational");
+    }
+
+    @Test
+    // IR rules can be used to verify collector-specific barrier info (in this
+    // case, that a ZGC barrier corresponds to a strong OOP reference). Barrier
+    // info can only be verified after matching, e.g. at the FINAL_CODE phase.
+    @IR(counts = {IRNode.Z_COMPARE_AND_SWAP_P_WITH_BARRIER_FLAG, "strong", "1"},
+        phase  = CompilePhase.FINAL_CODE)
+    static boolean testBarrierOfCompareAndSwap() {
+        return fVarHandle.compareAndSet(o, oldVal, newVal);
+    }
+}