8186125: "DU iteration must converge quickly" assert in split if with unsafe accesses

Added missing checks for Opaque4Node in split-if code

Reviewed-by: kvn
This commit is contained in:
Roland Westrelin 2017-11-09 12:43:13 -08:00
parent 04e375658c
commit 85d2a057a4
2 changed files with 134 additions and 13 deletions
src/hotspot/share/opto
test/hotspot/jtreg/compiler/unsafe

@ -116,9 +116,23 @@ bool PhaseIdealLoop::split_up( Node *n, Node *blk1, Node *blk2 ) {
assert( bol->is_Bool(), "" );
if (bol->outcnt() == 1) {
Node* use = bol->unique_out();
Node *use_c = use->is_If() ? use->in(0) : get_ctrl(use);
if (use_c == blk1 || use_c == blk2) {
continue;
if (use->Opcode() == Op_Opaque4) {
if (use->outcnt() == 1) {
Node* iff = use->unique_out();
assert(iff->is_If(), "unexpected node type");
Node *use_c = iff->in(0);
if (use_c == blk1 || use_c == blk2) {
continue;
}
}
} else {
// We might see an Opaque1 from a loop limit check here
assert(use->is_If() || use->is_CMove() || use->Opcode() == Op_Opaque1, "unexpected node type");
Node *use_c = use->is_If() ? use->in(0) : get_ctrl(use);
if (use_c == blk1 || use_c == blk2) {
assert(use->is_CMove(), "unexpected node type");
continue;
}
}
}
if (get_ctrl(bol) == blk1 || get_ctrl(bol) == blk2) {
@ -129,17 +143,40 @@ bool PhaseIdealLoop::split_up( Node *n, Node *blk1, Node *blk2 ) {
bol->dump();
}
#endif
for (DUIterator_Last jmin, j = bol->last_outs(jmin); j >= jmin; --j) {
// Uses are either IfNodes or CMoves
Node* iff = bol->last_out(j);
assert( iff->in(1) == bol, "" );
// Get control block of either the CMove or the If input
Node *iff_ctrl = iff->is_If() ? iff->in(0) : get_ctrl(iff);
Node *x = bol->clone();
register_new_node(x, iff_ctrl);
_igvn.replace_input_of(iff, 1, x);
for (DUIterator j = bol->outs(); bol->has_out(j); j++) {
Node* u = bol->out(j);
// Uses are either IfNodes, CMoves or Opaque4
if (u->Opcode() == Op_Opaque4) {
assert(u->in(1) == bol, "bad input");
for (DUIterator_Last kmin, k = u->last_outs(kmin); k >= kmin; --k) {
Node* iff = u->last_out(k);
assert(iff->is_If() || iff->is_CMove(), "unexpected node type");
assert( iff->in(1) == u, "" );
// Get control block of either the CMove or the If input
Node *iff_ctrl = iff->is_If() ? iff->in(0) : get_ctrl(iff);
Node *x1 = bol->clone();
Node *x2 = u->clone();
register_new_node(x1, iff_ctrl);
register_new_node(x2, iff_ctrl);
_igvn.replace_input_of(x2, 1, x1);
_igvn.replace_input_of(iff, 1, x2);
}
_igvn.remove_dead_node(u);
--j;
} else {
// We might see an Opaque1 from a loop limit check here
assert(u->is_If() || u->is_CMove() || u->Opcode() == Op_Opaque1, "unexpected node type");
assert(u->in(1) == bol, "");
// Get control block of either the CMove or the If input
Node *u_ctrl = u->is_If() ? u->in(0) : get_ctrl(u);
assert(u_ctrl != blk1 && u_ctrl != blk2, "won't converge");
Node *x = bol->clone();
register_new_node(x, u_ctrl);
_igvn.replace_input_of(u, 1, x);
--j;
}
}
_igvn.remove_dead_node( bol );
_igvn.remove_dead_node(bol);
--i;
}
}

@ -0,0 +1,84 @@
/*
* Copyright (c) 2017, 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 8186125
* @summary cast before unsafe access moved in dominating null check null path causes crash
* @modules java.base/jdk.internal.misc:+open
*
* @run main/othervm -XX:-BackgroundCompilation TestSplitIf
*
*/
import jdk.internal.misc.Unsafe;
import java.lang.reflect.Field;
public class TestSplitIf {
static final jdk.internal.misc.Unsafe UNSAFE = Unsafe.getUnsafe();
static final long F_OFFSET;
static class A {
int f;
A(int f) {
this.f = f;
}
}
static {
try {
Field fField = A.class.getDeclaredField("f");
F_OFFSET = UNSAFE.objectFieldOffset(fField);
} catch (Exception e) {
throw new RuntimeException(e);
}
}
static int test(A a1, A a2, boolean flag1) {
boolean flag2;
int f = 0;
A a = null;
if (flag1) {
flag2 = true;
a = a1;
} else {
flag2 = false;
a = a2;
}
if (flag2) {
f = UNSAFE.getInt(a, F_OFFSET);
} else {
f = UNSAFE.getInt(a, F_OFFSET);
}
return f;
}
static public void main(String[] args) {
A a = new A(0x42);
for (int i = 0; i < 20000; i++) {
test(a, a, (i % 2) == 0);
}
}
}