8332934: Do loop with continue with subsequent switch leads to incorrect stack maps

Reviewed-by: vromero

Author: liach

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

@@ -1192,11 +1192,7 @@ private void genLoop(JCStatement loop,
                     code.resolve(c.falseJumps);
                 }
             }
-            Chain exit = loopEnv.info.exit;
-            if (exit != null) {
-                code.resolve(exit);
-                exit.state.defined.excludeFrom(code.nextreg);
-            }
+            code.resolve(loopEnv.info.exit);
         }
 
     public void visitForeachLoop(JCEnhancedForLoop tree) {
@@ -1206,11 +1202,7 @@ public void visitForeachLoop(JCEnhancedForLoop tree) {
     public void visitLabelled(JCLabeledStatement tree) {
         Env<GenContext> localEnv = env.dup(tree, new GenContext());
         genStat(tree.body, localEnv, CRT_STATEMENT);
-        Chain exit = localEnv.info.exit;
-        if (exit != null) {
-            code.resolve(exit);
-            exit.state.defined.excludeFrom(code.nextreg);
-        }
+        code.resolve(localEnv.info.exit);
     }
 
     public void visitSwitch(JCSwitch tree) {
@@ -1413,11 +1405,7 @@ private void handleSwitch(JCTree swtch, JCExpression selector, List<JCCase> case
             }
 
             // Resolve all breaks.
-            Chain exit = switchEnv.info.exit;
-            if  (exit != null) {
-                code.resolve(exit);
-                exit.state.defined.excludeFrom(limit);
-            }
+            code.resolve(switchEnv.info.exit);
 
             // If we have not set the default offset, we do so now.
             if (code.get4(tableBase) == -1) {
@@ -2537,7 +2525,14 @@ void afterBody() {}
     /** code generation contexts,
      *  to be used as type parameter for environments.
      */
-    static class GenContext {
+    final class GenContext {
+
+        /**
+         * The top defined local variables for exit or continue branches to merge into.
+         * It may contain uninitialized variables to be initialized by branched code,
+         * so we cannot use Code.State.defined bits.
+         */
+        final int limit;
 
         /** A chain for all unresolved jumps that exit the current environment.
          */
@@ -2563,15 +2558,26 @@ static class GenContext {
          */
         ListBuffer<Integer> gaps = null;
 
+        GenContext() {
+            var code = Gen.this.code;
+            this.limit = code == null ? 0 : code.nextreg;
+        }
+
         /** Add given chain to exit chain.
          */
         void addExit(Chain c)  {
+            if (c != null) {
+                c.state.defined.excludeFrom(limit);
+            }
             exit = Code.mergeChains(c, exit);
         }
 
         /** Add given chain to cont chain.
          */
         void addCont(Chain c) {
+            if (c != null) {
+                c.state.defined.excludeFrom(limit);
+            }
             cont = Code.mergeChains(c, cont);
         }
     }

test/langtools/tools/javac/flow/LVTHarness.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2013, 2025, 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
@@ -157,6 +157,7 @@ void checkMethod(MethodModel method, AliveRanges ranges) {
 
         if (i < infoFromRanges.size()) {
             error(infoFromLVT, infoFromRanges, method.methodName().stringValue());
+            System.err.println(method.toDebugString());
         }
     }
 

test/langtools/tools/javac/BranchToFewerDefines.java renamed to test/langtools/tools/javac/stackmap/BranchToFewerDefines.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2014, 2025, 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
@@ -23,7 +23,7 @@
 
 /*
  * @test
- * @bug 8067429
+ * @bug 8067429 8332934
  * @summary java.lang.VerifyError: Inconsistent stackmap frames at branch target
  * @author srikanth
  *

test/langtools/tools/javac/stackmap/DoLoopLocalEscapeThroughContinueTest.java

@@ -0,0 +1,59 @@
+/*
+ * Copyright (c) 2025, 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 8332934
+ * @summary Incorrect defined locals escaped from continue in do loop
+ * @library /tools/lib /test/lib
+ * @run main DoLoopLocalEscapeThroughContinueTest
+ */
+
+import jdk.test.lib.ByteCodeLoader;
+import jdk.test.lib.compiler.InMemoryJavaCompiler;
+
+import java.lang.classfile.ClassFile;
+import java.lang.invoke.MethodHandles;
+
+public class DoLoopLocalEscapeThroughContinueTest {
+    public static void main(String... args) throws Throwable {
+        String source = """
+                static void main(String[] k) {
+                  do {
+                    int b = 1;
+                    continue;
+                  } while (Math.random() > 0.5D) ;
+                  switch (2) {
+                  case 3:
+                    double d;
+                  case 4:
+                    k.toString();
+                  }
+                }
+                """;
+        var bytes = InMemoryJavaCompiler.compile("Test", source, "-XDdebug.code");
+        System.out.println(ClassFile.of().parse(bytes).toDebugString());
+        var clz = ByteCodeLoader.load("Test", bytes);
+        MethodHandles.privateLookupIn(clz, MethodHandles.lookup()).ensureInitialized(clz); // force verification
+    }
+}

test/langtools/tools/javac/SwitchExitStateTest.java renamed to test/langtools/tools/javac/stackmap/SwitchExitStateTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2016, 2025, 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
@@ -23,7 +23,7 @@
 
 /*
  * @test
- * @bug 8160699
+ * @bug 8160699 8332934
  * @summary Verify that having finished executing a switch statement live locals are exactly the same as it was upon entry of the switch.
  * @run main SwitchExitStateTest
  */