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8155781: C2: opaque unsafe access triggers an assert

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Reviewed-by: kvn, lmesnik, ppunegov
This commit is contained in:
Vladimir Ivanov 2016-07-21 20:18:11 +03:00
parent 1ffdc57850
commit 1208854be7
2 changed files with 147 additions and 10 deletions
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23
hotspot/src/share/vm/opto/library_call.cpp
View File

@ -2405,8 +2405,13 @@ bool LibraryCallKit::inline_unsafe_access(bool is_store, const BasicType type, c
Compile::AliasType* alias_type = C->alias_type(adr_type);
assert(alias_type->index() != Compile::AliasIdxBot, "no bare pointers here");
assert(alias_type->adr_type() == TypeRawPtr::BOTTOM || alias_type->adr_type() == TypeOopPtr::BOTTOM ||
alias_type->basic_type() != T_ILLEGAL, "field, array element or unknown");
// Only field, array element or unknown locations are supported.
if (alias_type->adr_type() != TypeRawPtr::BOTTOM &&
alias_type->adr_type() != TypeOopPtr::BOTTOM &&
alias_type->basic_type() == T_ILLEGAL) {
return false;
}
bool mismatched = false;
BasicType bt = alias_type->basic_type();
if (bt != T_ILLEGAL) {
@ -2782,12 +2787,6 @@ bool LibraryCallKit::inline_unsafe_load_store(const BasicType type, const LoadSt
ShouldNotReachHere();
}
// Null check receiver.
receiver = null_check(receiver);
if (stopped()) {
return true;
}
// Build field offset expression.
// We currently rely on the cookies produced by Unsafe.xxxFieldOffset
// to be plain byte offsets, which are also the same as those accepted
@ -2799,8 +2798,6 @@ bool LibraryCallKit::inline_unsafe_load_store(const BasicType type, const LoadSt
const TypePtr *adr_type = _gvn.type(adr)->isa_ptr();
Compile::AliasType* alias_type = C->alias_type(adr_type);
assert(alias_type->adr_type() == TypeRawPtr::BOTTOM || alias_type->adr_type() == TypeOopPtr::BOTTOM ||
alias_type->basic_type() != T_ILLEGAL, "field, array element or unknown");
BasicType bt = alias_type->basic_type();
if (bt != T_ILLEGAL &&
((bt == T_OBJECT || bt == T_ARRAY) != (type == T_OBJECT))) {
@ -2832,6 +2829,12 @@ bool LibraryCallKit::inline_unsafe_load_store(const BasicType type, const LoadSt
ShouldNotReachHere();
}
// Null check receiver.
receiver = null_check(receiver);
if (stopped()) {
return true;
}
int alias_idx = C->get_alias_index(adr_type);
// Memory-model-wise, a LoadStore acts like a little synchronized

134
hotspot/test/compiler/unsafe/OpaqueAccesses.java Normal file
View File

@ -0,0 +1,134 @@
/*
* Copyright (c) 2016, 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. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* 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 8155781
* @modules java.base/jdk.internal.misc
*
* @run main/bootclasspath/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:+UnlockDiagnosticVMOptions
* -XX:-TieredCompilation -Xbatch
* -XX:CompileCommand=dontinline,compiler.unsafe.OpaqueAccesses::test*
* compiler.unsafe.OpaqueAccesses
*/
package compiler.unsafe;
import jdk.internal.misc.Unsafe;
import java.lang.reflect.Field;
public class OpaqueAccesses {
private static final Unsafe UNSAFE = Unsafe.getUnsafe();
private static final Object INSTANCE = new OpaqueAccesses();
private static final Object[] ARRAY = new Object[10];
private static final long F_OFFSET;
private static final long E_OFFSET;
static {
try {
Field field = OpaqueAccesses.class.getDeclaredField("f");
F_OFFSET = UNSAFE.objectFieldOffset(field);
E_OFFSET = UNSAFE.arrayBaseOffset(ARRAY.getClass());
} catch (NoSuchFieldException e) {
throw new Error(e);
}
}
private Object f = new Object();
static Object testFixedOffsetField(Object o) {
return UNSAFE.getObject(o, F_OFFSET);
}
static int testFixedOffsetHeader0(Object o) {
return UNSAFE.getInt(o, 0);
}
static int testFixedOffsetHeader4(Object o) {
return UNSAFE.getInt(o, 4);
}
static Object testFixedBase(long off) {
return UNSAFE.getObject(INSTANCE, off);
}
static Object testOpaque(Object o, long off) {
return UNSAFE.getObject(o, off);
}
static int testFixedOffsetHeaderArray0(Object[] arr) {
return UNSAFE.getInt(arr, 0);
}
static int testFixedOffsetHeaderArray4(Object[] arr) {
return UNSAFE.getInt(arr, 4);
}
static Object testFixedOffsetArray(Object[] arr) {
return UNSAFE.getObject(arr, E_OFFSET);
}
static Object testFixedBaseArray(long off) {
return UNSAFE.getObject(ARRAY, off);
}
static Object testOpaqueArray(Object[] o, long off) {
return UNSAFE.getObject(o, off);
}
static final long ADDR = UNSAFE.allocateMemory(10);
static boolean flag;
static int testMixedAccess() {
flag = !flag;
Object o = (flag ? INSTANCE : null);
long off = (flag ? F_OFFSET : ADDR);
return UNSAFE.getInt(o, off);
}
public static void main(String[] args) {
for (int i = 0; i < 20_000; i++) {
// Instance
testFixedOffsetField(INSTANCE);
testFixedOffsetHeader0(INSTANCE);
testFixedOffsetHeader4(INSTANCE);
testFixedBase(F_OFFSET);
testOpaque(INSTANCE, F_OFFSET);
testMixedAccess();
// Array
testFixedOffsetHeaderArray0(ARRAY);
testFixedOffsetHeaderArray4(ARRAY);
testFixedOffsetArray(ARRAY);
testFixedBaseArray(E_OFFSET);
testOpaqueArray(ARRAY, E_OFFSET);
}
System.out.println("TEST PASSED");
}
}