packages/openjdk-1.8.0
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
openjdk-1.8.0/8191915.patch

162 lines
6.1 KiB
Diff
Raw Blame History

From a1125b79426556114c36a807ccd95bd916b07dab Mon Sep 17 00:00:00 2001
Date: Fri, 22 Jan 2021 15:26:12 +0800
Subject: 8191915: java.lang.Math.multiplyExact not throw an
exception for certain values
Summary: C2: java.lang.Math.multiplyExact not throw an exception for certain values
LLT: hotspot/test/compiler/intrinsics/mathexact/LongMulOverflowTest.java
Bug url: https://bugs.openjdk.java.net/browse/JDK-8191915
---
hotspot/src/share/vm/opto/mathexactnode.cpp | 42 ++++++++-----
hotspot/src/share/vm/opto/mathexactnode.hpp | 4 +-
.../mathexact/LongMulOverflowTest.java | 61 +++++++++++++++++++
3 files changed, 90 insertions(+), 17 deletions(-)
create mode 100644 hotspot/test/compiler/intrinsics/mathexact/LongMulOverflowTest.java
diff --git a/hotspot/src/share/vm/opto/mathexactnode.cpp b/hotspot/src/share/vm/opto/mathexactnode.cpp
index 00466ad3d..661cc745b 100644
--- a/hotspot/src/share/vm/opto/mathexactnode.cpp
+++ b/hotspot/src/share/vm/opto/mathexactnode.cpp
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2013, 2018, 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
@@ -117,23 +117,33 @@ bool OverflowSubLNode::will_overflow(jlong v1, jlong v2) const {
return SubHelper<OverflowSubLNode>::will_overflow(v1, v2);
}
-bool OverflowMulLNode::will_overflow(jlong val1, jlong val2) const {
- jlong result = val1 * val2;
- jlong ax = (val1 < 0 ? -val1 : val1);
- jlong ay = (val2 < 0 ? -val2 : val2);
-
- bool overflow = false;
- if ((ax | ay) & CONST64(0xFFFFFFFF00000000)) {
- // potential overflow if any bit in upper 32 bits are set
- if ((val1 == min_jlong && val2 == -1) || (val2 == min_jlong && val1 == -1)) {
- // -1 * Long.MIN_VALUE will overflow
- overflow = true;
- } else if (val2 != 0 && (result / val2 != val1)) {
- overflow = true;
- }
+bool OverflowMulLNode::is_overflow(jlong val1, jlong val2) {
+ // x * { 0, 1 } will never overflow. Even for x = min_jlong
+ if (val1 == 0 || val2 == 0 || val1 == 1 || val2 == 1) {
+ return false;
+ }
+
+ // x * min_jlong for x not in { 0, 1 } overflows
+ // even -1 as -1 * min_jlong is an overflow
+ if (val1 == min_jlong || val2 == min_jlong) {
+ return true;
}
- return overflow;
+ // if (x * y) / y == x there is no overflow
+ //
+ // the multiplication here is done as unsigned to avoid undefined behaviour which
+ // can be used by the compiler to assume that the check further down (result / val2 != val1)
+ // is always false and breaks the overflow check
+ julong v1 = (julong) val1;
+ julong v2 = (julong) val2;
+ julong tmp = v1 * v2;
+ jlong result = (jlong) tmp;
+
+ if (result / val2 != val1) {
+ return true;
+ }
+
+ return false;
}
bool OverflowAddINode::can_overflow(const Type* t1, const Type* t2) const {
diff --git a/hotspot/src/share/vm/opto/mathexactnode.hpp b/hotspot/src/share/vm/opto/mathexactnode.hpp
index 3e037cf56..0a59ebd96 100644
--- a/hotspot/src/share/vm/opto/mathexactnode.hpp
+++ b/hotspot/src/share/vm/opto/mathexactnode.hpp
@@ -129,8 +129,10 @@ public:
OverflowMulLNode(Node* in1, Node* in2) : OverflowLNode(in1, in2) {}
virtual int Opcode() const;
- virtual bool will_overflow(jlong v1, jlong v2) const;
+ virtual bool will_overflow(jlong v1, jlong v2) const { return is_overflow(v1, v2); }
virtual bool can_overflow(const Type* t1, const Type* t2) const;
+
+ static bool is_overflow(jlong v1, jlong v2);
};
#endif
diff --git a/hotspot/test/compiler/intrinsics/mathexact/LongMulOverflowTest.java b/hotspot/test/compiler/intrinsics/mathexact/LongMulOverflowTest.java
new file mode 100644
index 000000000..69bd8f157
--- /dev/null
+++ b/hotspot/test/compiler/intrinsics/mathexact/LongMulOverflowTest.java
@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) 2018, 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 8191915
+ * @summary Regression test for multiplyExact intrinsic
+ * @compile AddExactICondTest.java
+ * @run main/othervm -Xcomp -XX:-TieredCompilation compiler.intrinsics.mathexact.LongMulOverflowTest
+ */
+
+package compiler.intrinsics.mathexact;
+
+public class LongMulOverflowTest {
+ public static void main(String[] args) {
+ LongMulOverflowTest test = new LongMulOverflowTest();
+ for (int i = 0; i < 10; ++i) {
+ try {
+ test.runTest();
+ throw new RuntimeException("Error, runTest() did not overflow!");
+ } catch (ArithmeticException e) {
+ // success
+ }
+
+ try {
+ test.runTestOverflow();
+ throw new RuntimeException("Error, runTestOverflow() did not overflow!");
+ } catch (ArithmeticException e) {
+ // success
+ }
+ }
+ }
+
+ public void runTest() {
+ java.lang.Math.multiplyExact(Long.MIN_VALUE, 7);
+ }
+
+ public void runTestOverflow() {
+ java.lang.Math.multiplyExact((Long.MAX_VALUE / 2) + 1, 2);
+ }
+}
--
2.19.0
Reference in New Issue View Git Blame Copy Permalink