8285394: Compiler blackholes can be eliminated due to stale ciMethod::intrinsic_id()

Reviewed-by: kvn
Backport-of: ce8db2c40378de01ce35ca37ec315af47974d6d6

Author: shipilev

src/hotspot/share/ci/ciMethod.cpp

@@ -82,7 +82,6 @@ ciMethod::ciMethod(const methodHandle& h_m, ciInstanceKlass* holder) :
   _max_stack          = h_m->max_stack();
   _max_locals         = h_m->max_locals();
   _code_size          = h_m->code_size();
-  _intrinsic_id       = h_m->intrinsic_id();
   _handler_count      = h_m->exception_table_length();
   _size_of_parameters = h_m->size_of_parameters();
   _uses_monitors      = h_m->access_flags().has_monitor_bytecodes();
@@ -102,6 +101,10 @@ ciMethod::ciMethod(const methodHandle& h_m, ciInstanceKlass* holder) :
   _bcea               = NULL;
 #endif // COMPILER2
 
+  // Check for blackhole intrinsic and then populate the intrinsic ID.
+  CompilerOracle::tag_blackhole_if_possible(h_m);
+  _intrinsic_id       = h_m->intrinsic_id();
+
   ciEnv *env = CURRENT_ENV;
   if (env->jvmti_can_hotswap_or_post_breakpoint()) {
     // 6328518 check hotswap conditions under the right lock.
@@ -157,8 +160,6 @@ ciMethod::ciMethod(const methodHandle& h_m, ciInstanceKlass* holder) :
     ciReplay::initialize(this);
   }
 #endif
-
-  CompilerOracle::tag_blackhole_if_possible(h_m);
 }
 
 

test/hotspot/jtreg/compiler/c2/irTests/blackhole/BlackholeHotInlineTest.java

@@ -0,0 +1,103 @@
+/*
+ * Copyright (c) 2022, Red Hat, Inc. 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 8285394
+ * @requires vm.compiler2.enabled
+ * @summary Blackholes should work when hot inlined
+ * @library /test/lib /
+ * @run driver compiler.c2.irTests.blackhole.BlackholeHotInlineTest
+ */
+
+package compiler.c2.irTests.blackhole;
+
+import compiler.lib.ir_framework.*;
+import jdk.test.lib.Asserts;
+
+public class BlackholeHotInlineTest {
+
+    public static void main(String[] args) {
+        TestFramework.runWithFlags(
+            "-XX:+UnlockExperimentalVMOptions",
+            "-XX:CompileThreshold=100",
+            "-XX:-TieredCompilation",
+            "-XX:CompileCommand=blackhole,compiler.c2.irTests.blackhole.BlackholeHotInlineTest::blackhole",
+            "-XX:CompileCommand=dontinline,compiler.c2.irTests.blackhole.BlackholeHotInlineTest::dontinline"
+        );
+    }
+
+    static long x, y;
+
+    /*
+     * Negative test: check that dangling expression is eliminated
+     */
+
+    @Test
+    @IR(failOn = IRNode.MUL_L)
+    static void testNothing() {
+        long r = x * y;
+    }
+
+    @Run(test = "testNothing")
+    static void runNothing() {
+        testNothing();
+    }
+
+    /*
+     * Auxiliary test: check that dontinline method does not allow the elimination.
+     */
+
+    @Test
+    @IR(counts = {IRNode.MUL_L, "1"})
+    static void testDontline() {
+        long r = x * y;
+        dontinline(r);
+    }
+
+    static void dontinline(long x) {}
+
+    @Run(test = "testDontline")
+    static void runDontinline() {
+        testDontline();
+    }
+
+    /*
+     * Positive test: check that blackhole method does not allow the elimination either.
+     */
+
+    @Test
+    @IR(counts = {IRNode.MUL_L, "1"})
+    static void testBlackholed() {
+        long r = x * y;
+        blackhole(r);
+    }
+
+    static void blackhole(long x) {}
+
+    @Run(test = "testBlackholed")
+    static void runBlackholed() {
+        testBlackholed();
+    }
+
+}

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

@@ -141,6 +141,7 @@ public class IRNode {
     public static final String LSHIFT_L = START + "LShiftL" + MID + END;
     public static final String ADD_I = START + "AddI" + MID + END;
     public static final String ADD_L = START + "AddL" + MID + END;
+    public static final String MUL_L = START + "MulL" + MID + END;
     public static final String CONV_I2L = START + "ConvI2L" + MID + END;
     public static final String POPCOUNT_L = START + "PopCountL" + MID + END;