8155028: javac crashes in silly do-while loop
Summary: Compiler should short circuit code generation for unreachable code.
Reviewed-by: mcimadamore
--- a/langtools/src/jdk.compiler/share/classes/com/sun/tools/javac/jvm/Gen.java Fri Apr 29 16:06:52 2016 -0700
+++ b/langtools/src/jdk.compiler/share/classes/com/sun/tools/javac/jvm/Gen.java Mon May 02 10:11:24 2016 +0530
@@ -1086,17 +1086,19 @@
genStat(body, loopEnv, CRT_STATEMENT | CRT_FLOW_TARGET);
code.resolve(loopEnv.info.cont);
genStats(step, loopEnv);
- CondItem c;
- if (cond != null) {
- code.statBegin(cond.pos);
+ if (code.isAlive()) {
+ CondItem c;
+ if (cond != null) {
+ code.statBegin(cond.pos);
+ Assert.check(code.state.stacksize == 0);
+ c = genCond(TreeInfo.skipParens(cond), CRT_FLOW_CONTROLLER);
+ } else {
+ c = items.makeCondItem(goto_);
+ }
+ code.resolve(c.jumpTrue(), startpc);
Assert.check(code.state.stacksize == 0);
- c = genCond(TreeInfo.skipParens(cond), CRT_FLOW_CONTROLLER);
- } else {
- c = items.makeCondItem(goto_);
+ code.resolve(c.falseJumps);
}
- code.resolve(c.jumpTrue(), startpc);
- Assert.check(code.state.stacksize == 0);
- code.resolve(c.falseJumps);
}
Chain exit = loopEnv.info.exit;
if (exit != null) {
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/UnreachableLoopCond.java Mon May 02 10:11:24 2016 +0530
@@ -0,0 +1,85 @@
+/*
+ * 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.
+ *
+ * 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 8155028
+ * @summary javac crashes in silly do-while loop
+ * @compile UnreachableLoopCond.java
+ */
+
+class UnreachableLoopCond {
+
+ public void foo() {
+ Integer i = 100;
+ do {
+ return;
+ } while (i++ < 10);
+ }
+
+ public void goo() {
+ Integer i = 100;
+ do {
+ break;
+ } while (i++ < 10);
+ }
+
+ public void zoo() {
+ Integer i = 100;
+ do {
+ throw new RuntimeException();
+ } while (i++ < 10);
+ }
+
+ public void loo() {
+ Integer i = 100;
+ Integer j = 100;
+ do {
+ do {
+ return;
+ } while (i++ < 10);
+ } while (j++ < 10);
+ }
+
+ public void moo() {
+ Integer i = 100;
+ do {
+ if (true) {
+ return;
+ } else {
+ return;
+ }
+ } while (i++ < 10);
+ }
+
+ public void moo(boolean cond) {
+ Integer i = 100;
+ do {
+ if (cond) {
+ return;
+ } else {
+ return;
+ }
+ } while (i++ < 10);
+ }
+}