8271055: Crash during deoptimization with "assert(bb->is_reachable()) failed: getting result from unreachable basicblock" with -XX:+VerifyStack

src/hotspot/share/oops/generateOopMap.cpp

@@ -1171,8 +1171,11 @@ void GenerateOopMap::interp_bb(BasicBlock *bb) {
 }
 
 void GenerateOopMap::do_exception_edge(BytecodeStream* itr) {
-  // Only check exception edge, if bytecode can trap
-  if (!Bytecodes::can_trap(itr->code())) return;
+  // Check exception edge even if bytecode can not trap since some bytecodes
+  // in try-block will never throw an exception, thus exception handler basic
+  // blocks becomes unreachable. For such cases, these unreachable basic blocks
+  // confuse later OopMap generation.
+
   switch (itr->code()) {
     case Bytecodes::_aload_0:
       // These bytecodes can trap for rewriting.  We need to assume that

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

@@ -1518,6 +1518,11 @@ void genTry(JCTree body, List<JCCatch> catchers, Env<GenContext> env) {
             int startpc = code.curCP();
             Code.State stateTry = code.state.dup();
             genStat(body, env, CRT_BLOCK);
+            if (startpc == code.curCP()) {
+                // Put a "nop" into try block even if it is empty because we want
+                // to generate exception table within code attribute.
+                code.emitop0(nop);
+            }
             int endpc = code.curCP();
             List<Integer> gaps = env.info.gaps.toList();
             code.statBegin(TreeInfo.endPos(body));

test/hotspot/jtreg/compiler/interpreter/VerifyStackWithUnreachableBlock.java

@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2021, Alibaba Group Holding Limited. 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 VerifyStackWithUnreachableBlock
+ * @bug 8271055
+ * @compile VerifyStackWithUnreachableBlock.java
+ * @summary Using VerifyStack for method that contains unreachable basic blocks
+ * @run main/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:+VerifyStack compiler.interpreter.VerifyStackWithUnreachableBlock
+ */
+
+package compiler.interpreter;
+
+public class VerifyStackWithUnreachableBlock {
+    public static void main(String[] strArr) {
+        VerifyStackWithUnreachableBlock _instance = new VerifyStackWithUnreachableBlock();
+        for (int i = 0; i < 10000; i++) {
+            _instance.test();
+        }
+    }
+
+    void test() {
+        int i8 = 1;
+        try {
+            ;
+        } finally {
+            for (; i8 < 100; i8++) {
+            }
+        }
+    }
+}