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8235332: TestInstanceCloneAsLoadsStores.java fails with -XX:+StressGCM

Account for GC barriers when skipping a cloned ArrayCopyNode in ConnectionGraph::find_inst_mem()

Reviewed-by: roland, neliasso
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Christian Hagedorn
Christian Hagedorn committed Jan 31, 2020
1 parent 4122968 commit b940e17c9efcaf91fa7f16d953fbfd820eea1eff
@@ -2746,11 +2746,14 @@ Node* ConnectionGraph::find_inst_mem(Node *orig_mem, int alias_idx, GrowableArra
result = proj_in->in(TypeFunc::Memory);
}
} else if (proj_in->is_MemBar()) {
if (proj_in->in(TypeFunc::Memory)->is_MergeMem() &&
proj_in->in(TypeFunc::Memory)->as_MergeMem()->in(Compile::AliasIdxRaw)->is_Proj() &&
proj_in->in(TypeFunc::Memory)->as_MergeMem()->in(Compile::AliasIdxRaw)->in(0)->is_ArrayCopy()) {
// clone
ArrayCopyNode* ac = proj_in->in(TypeFunc::Memory)->as_MergeMem()->in(Compile::AliasIdxRaw)->in(0)->as_ArrayCopy();
// Check if there is an array copy for a clone
// Step over GC barrier when ReduceInitialCardMarks is disabled
BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
Node* control_proj_ac = bs->step_over_gc_barrier(proj_in->in(0));

if (control_proj_ac->is_Proj() && control_proj_ac->in(0)->is_ArrayCopy()) {
// Stop if it is a clone
ArrayCopyNode* ac = control_proj_ac->in(0)->as_ArrayCopy();
if (ac->may_modify(toop, igvn)) {
break;
}
@@ -0,0 +1,102 @@
/*
* Copyright (c) 2020, 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 8235332
* @summary Test cloning with more than 8 (=ArrayCopyLoadStoreMaxElem) fields with StressGCM
* @library /
*
* @run main/othervm -Xbatch
* -XX:CompileCommand=dontinline,compiler.arraycopy.TestCloneAccessStressGCM::test
* -XX:+UnlockDiagnosticVMOptions -XX:+StressGCM -XX:-ReduceInitialCardMarks
* compiler.arraycopy.TestCloneAccessStressGCM
*/

package compiler.arraycopy;

public class TestCloneAccessStressGCM {

static int test(E src) throws CloneNotSupportedException {
// ArrayCopyNode for this clone is not inlined since there are more than 8 (=ArrayCopyLoadStoreMaxElem) fields
E dest = (E)src.clone();

// The ArrayCopyNode initialization for the clone is executed after the LoadI nodes for 'dest' due to a
// memory input from the uninitialized new object instead of the ArrayCopyNode. As a result, uninitialized
// memory is read for each field and added together.
return dest.i1 + dest.i2 + dest.i3 + dest.i4 + dest.i5 +
dest.i6 + dest.i7 + dest.i8 + dest.i9;
}

public static void main(String[] args) throws Exception {
TestCloneAccessStressGCM test = new TestCloneAccessStressGCM();
int result = 0;
E e = new E();
for (int i = 0; i < 20000; i++) {
result = test(e);
if (result != 36) {
throw new RuntimeException("Return value not 36. Got: " + result + "; additional check: " + e.sum());
}
}

if (result != 36) {
throw new RuntimeException("Return value not 36. Got: " + result + "; additional check: " + e.sum());
}
}
}

class E implements Cloneable {
/*
* Need more than 8 (=ArrayCopyLoadStoreMaxElem) fields
*/
int i1;
int i2;
int i3;
int i4;
int i5;
int i6;
int i7;
int i8;
int i9;

E() {
i1 = 0;
i2 = 1;
i3 = 2;
i4 = 3;
i5 = 4;
i6 = 5;
i7 = 6;
i8 = 7;
i9 = 8;
}

public Object clone() throws CloneNotSupportedException {
return super.clone();
}

public int sum() {
return i1 + i2 + i3 + i4 + i5 + i6 + i7 + i8 + i9;
}
}

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