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8273409: Receiver type narrowed by CCP does not always trigger post-p…
…arse call devirtualization

Reviewed-by: vlivanov, neliasso
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TobiHartmann committed Sep 9, 2021
1 parent 5ca26cb commit 4866eaa997b2ee2a47bdcd0d96202f220fb2774d
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@@ -1967,7 +1967,9 @@ Node *PhaseCCP::transform_once( Node *n ) {

// TEMPORARY fix to ensure that 2nd GVN pass eliminates NULL checks
switch( n->Opcode() ) {
case Op_FastLock: // Revisit FastLocks for lock coarsening
case Op_CallStaticJava: // Give post-parse call devirtualization a chance
case Op_CallDynamicJava:
case Op_FastLock: // Revisit FastLocks for lock coarsening
case Op_If:
case Op_CountedLoopEnd:
case Op_Region:
@@ -0,0 +1,200 @@
/*
* Copyright (c) 2021, 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 compiler.c2.irTests;

import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandles;
import java.lang.invoke.MethodType;
import jdk.test.lib.Asserts;
import compiler.lib.ir_framework.*;

/*
* @test
* @bug 8273409
* @summary Test that post-parse call devirtualization works as intended.
* @library /test/lib /
* @run driver compiler.c2.irTests.TestPostParseCallDevirtualization
*/
public class TestPostParseCallDevirtualization {

public static void main(String[] args) {
TestFramework framework = new TestFramework();
Scenario noOSR = new Scenario(0, "-XX:-UseOnStackReplacement");
Scenario alwaysIncremental = new Scenario(1, "-XX:-UseOnStackReplacement", "-XX:+IgnoreUnrecognizedVMOptions", "-XX:+AlwaysIncrementalInline");
framework.addScenarios(noOSR, alwaysIncremental).start();
}

static interface I {
public int method();
}

static final class A implements I {
@Override
public int method() { return 0; };
}

static final class B implements I {
@Override
public int method() { return 42; };
}

static final class C implements I {
@Override
public int method() { return -1; };
}

static final A a = new A();
static final B b = new B();
static final C c = new C();

static int callHelper(I recv) {
// Receiver profile is polluted
return recv.method();
}

@Test
@IR(failOn = {IRNode.DYNAMIC_CALL_OF_METHOD, "method"},
counts = {IRNode.STATIC_CALL_OF_METHOD, "method", "= 1"})
public int testDynamicCallWithLoop(B val) {
// Make sure val is non-null below
if (val == null) {
return 0;
}
// Loop that triggers loop opts
I recv = a;
for (int i = 0; i < 3; ++i) {
if (i > 1) {
recv = val;
}
}
// We only know after loop opts that the receiver type is non-null B.
// Post-parse call devirtualization should then convert the
// virtual call in the helper method to a static call.
return callHelper(recv);
}

@Run(test = "testDynamicCallWithLoop")
public void checkTestDynamicCallWithLoop() {
// Pollute receiver profile with three different
// types to prevent (bimorphic) inlining.
callHelper(a);
callHelper(b);
callHelper(c);
Asserts.assertEquals(testDynamicCallWithLoop(b), 42);
}

@Test
@IR(failOn = {IRNode.DYNAMIC_CALL_OF_METHOD, "method"},
counts = {IRNode.STATIC_CALL_OF_METHOD, "method", "= 1"})
public int testDynamicCallWithCCP(B val) {
// Make sure val is non-null below
if (val == null) {
return 0;
}
// Loop that triggers CCP
I recv = a;
for (int i = 0; i < 100; i++) {
if ((i % 2) == 0) {
recv = val;
}
}
// We only know after CCP that the receiver type is non-null B.
// Post-parse call devirtualization should then convert the
// virtual call in the helper method to a static call.
return callHelper(recv);
}

@Run(test = "testDynamicCallWithCCP")
public void checkTestDynamicCallWithCCP() {
// Pollute receiver profile with three different
// types to prevent (bimorphic) inlining.
callHelper(a);
callHelper(b);
callHelper(c);
Asserts.assertEquals(testDynamicCallWithCCP(b), 42);
}

static final MethodHandle mh1;
static final MethodHandle mh2;

static {
try {
MethodHandles.Lookup lookup = MethodHandles.lookup();
mh1 = lookup.findStatic(TestPostParseCallDevirtualization.class, "method1", MethodType.methodType(int.class));
mh2 = lookup.findStatic(TestPostParseCallDevirtualization.class, "method2", MethodType.methodType(int.class));
} catch (NoSuchMethodException | IllegalAccessException e) {
e.printStackTrace();
throw new RuntimeException("Method handle lookup failed");
}
}

static int method1() { return 0; }
static int method2() { return 42; }

@Test
@IR(failOn = {IRNode.STATIC_CALL_OF_METHOD, "invokeBasic"},
counts = {IRNode.STATIC_CALL_OF_METHOD, "invokeStatic", "= 1"})
public int testMethodHandleCallWithLoop() throws Throwable {
MethodHandle mh = mh1;
for (int i = 0; i < 3; ++i) {
if (i > 1) {
mh = mh2;
}
}
// We only know after loop opts that the receiver is mh2.
// Post-parse call devirtualization should then convert the
// virtual call to a static call.
return (int)mh.invokeExact();
}

@Run(test = "testMethodHandleCallWithLoop")
public void checkTestMethodHandleCallWithLoop() throws Throwable {
Asserts.assertEquals(testMethodHandleCallWithLoop(), 42);
}

@Test
@IR(failOn = {IRNode.STATIC_CALL_OF_METHOD, "invokeBasic"},
counts = {IRNode.STATIC_CALL_OF_METHOD, "invokeStatic", "= 1"})
public int testMethodHandleCallWithCCP() throws Throwable {
MethodHandle mh = mh1;
int limit = 0;
for (int i = 0; i < 100; i++) {
if ((i % 2) == 0) {
limit = 1;
}
}
for (int i = 0; i < limit; ++i) {
mh = mh2;
}
// We only know after CCP that the receiver is mh2.
// Post-parse call devirtualization should then convert the
// virtual call to a static call.
return (int)mh.invokeExact();
}

@Run(test = "testMethodHandleCallWithCCP")
public void checkTestMethodHandleCallWithCCP() throws Throwable {
Asserts.assertEquals(testMethodHandleCallWithCCP(), 42);
}
}
@@ -115,6 +115,8 @@ public class IRNode {
public static final String COUNTEDLOOP_MAIN = START + "CountedLoop\\b" + MID + "main" + END;

public static final String CALL = START + "CallStaticJava" + MID + END;
public static final String DYNAMIC_CALL_OF_METHOD = COMPOSITE_PREFIX + START + "CallDynamicJava" + MID + IS_REPLACED + END;
public static final String STATIC_CALL_OF_METHOD = COMPOSITE_PREFIX + START + "CallStaticJava" + MID + IS_REPLACED + END;
public static final String TRAP = START + "CallStaticJava" + MID + "uncommon_trap.*reason" + END;
public static final String PREDICATE_TRAP = START + "CallStaticJava" + MID + "uncommon_trap.*predicate" + END;
public static final String UNSTABLE_IF_TRAP = START + "CallStaticJava" + MID + "uncommon_trap.*unstable_if" + END;

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