8134759: jdb: Incorrect stepping inside finally block

Add LineNumberTable attribute for return bytecodes split around finally code

Reviewed-by: mcimadamore

langtools/src/jdk.compiler/share/classes/com/sun/tools/javac/jvm/Gen.java

@@ -1697,6 +1697,11 @@ public class Gen extends JCTree.Visitor {
     public void visitReturn(JCReturn tree) {
         int limit = code.nextreg;
         final Env<GenContext> targetEnv;
+
+        /* Save and then restore the location of the return in case a finally
+         * is expanded (with unwind()) in the middle of our bytecodes.
+         */
+        int tmpPos = code.pendingStatPos;
         if (tree.expr != null) {
             Item r = genExpr(tree.expr, pt).load();
             if (hasFinally(env.enclMethod, env)) {
@@ -1704,17 +1709,10 @@ public class Gen extends JCTree.Visitor {
                 r.store();
             }
             targetEnv = unwind(env.enclMethod, env);
+            code.pendingStatPos = tmpPos;
             r.load();
             code.emitop0(ireturn + Code.truncate(Code.typecode(pt)));
         } else {
-            /*  If we have a statement like:
-             *
-             *  return;
-             *
-             *  we need to store the code.pendingStatPos value before generating
-             *  the finalizer.
-             */
-            int tmpPos = code.pendingStatPos;
             targetEnv = unwind(env.enclMethod, env);
             code.pendingStatPos = tmpPos;
             code.emitop0(return_);

langtools/test/tools/javac/linenumbers/FinallyLineNumberTest.java

@@ -0,0 +1,108 @@
+/*
+ * Copyright (c) 2015, 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 8134759
+ * @summary Add LineNumberTable attribute for return bytecodes split around finally code
+ * @modules jdk.jdeps/com.sun.tools.classfile
+ */
+
+import com.sun.tools.classfile.ClassFile;
+import com.sun.tools.classfile.ConstantPoolException;
+import com.sun.tools.classfile.Method;
+import com.sun.tools.classfile.Attribute;
+import com.sun.tools.classfile.Code_attribute;
+import com.sun.tools.classfile.LineNumberTable_attribute;
+import com.sun.tools.classfile.LineNumberTable_attribute.Entry;
+
+import java.io.File;
+import java.io.IOException;
+
+public class FinallyLineNumberTest {
+    public static void main(String[] args) throws Exception {
+        // check that we have 5 consecutive entries for method()
+        Entry[] lines = findEntries();
+        if (lines == null) {
+            throw new Exception("finally line number table could not be loaded");
+        }
+        if (lines.length != 4) {
+            // Help debug
+            System.err.println("LineTable error, got lines:");
+            for (Entry e : lines) {
+                System.err.println(e.line_number);
+            }
+            throw new Exception("finally line number table incorrect: length=" + lines.length + " expected length=4");
+        }
+
+        // return null line, for the load null operation
+        int current = lines[0].line_number;
+        int first = current;
+
+        // finally line
+        current = lines[1].line_number;
+        if (current != first + 2) {
+            throw new Exception("finally line number table incorrect: got=" + current + " expected=" + (first + 2));
+        }
+
+        // return null line, for the return operation
+        current = lines[2].line_number;
+        if (current != first) {
+            throw new Exception("finally line number table incorrect: got=" + current + " expected=" + first);
+        }
+
+        // finally line, for when exception is thrown
+        current = lines[3].line_number;
+        if (current != first + 2) {
+            throw new Exception("finally line number table incorrect: got=" + current + " expected=" + (first + 2));
+        }
+    }
+
+    static Entry[] findEntries() throws IOException, ConstantPoolException {
+        ClassFile self = ClassFile.read(FinallyLineNumberTest.class.getResourceAsStream("FinallyLineNumberTest.class"));
+        for (Method m : self.methods) {
+            if ("method".equals(m.getName(self.constant_pool))) {
+                Code_attribute code_attribute = (Code_attribute)m.attributes.get(Attribute.Code);
+                for (Attribute at : code_attribute.attributes) {
+                    if (Attribute.LineNumberTable.equals(at.getName(self.constant_pool))) {
+                        return ((LineNumberTable_attribute)at).line_number_table;
+                    }
+                }
+            }
+        }
+        return null;
+    }
+
+    // This method should get LineNumberTable entries for:
+    // *) The load of the null
+    // *) The finally code for when an exception is *not* thrown
+    // *) The actual return, which should have the same line as the load of the null
+    // *) The finally code for when an exception *is* thrown, should have the same line as above finally code
+    public static String method(int field) {
+        try {
+            return null;
+        } finally {
+            field+=1; // Dummy
+        }
+    }
+}