8026749: Missing LV table in lambda bodies

Reviewed-by: vromero, jlahoda

langtools/src/share/classes/com/sun/tools/javac/code/Flags.java

@@ -270,6 +270,11 @@ public class Flags {
      */
     public static final long POTENTIALLY_AMBIGUOUS = 1L<<48;
 
+    /**
+     * Flag that marks a synthetic method body for a lambda expression
+     */
+    public static final long LAMBDA_METHOD = 1L<<49;
+
     /** Modifier masks.
      */
     public static final int
@@ -378,7 +383,8 @@ public class Flags {
         NOT_IN_PROFILE(Flags.NOT_IN_PROFILE),
         BAD_OVERRIDE(Flags.BAD_OVERRIDE),
         SIGNATURE_POLYMORPHIC(Flags.SIGNATURE_POLYMORPHIC),
-        THROWS(Flags.THROWS);
+        THROWS(Flags.THROWS),
+        LAMBDA_METHOD(Flags.LAMBDA_METHOD);
 
         Flag(long flag) {
             this.value = flag;

langtools/src/share/classes/com/sun/tools/javac/comp/Flow.java

@@ -1718,9 +1718,9 @@ public class Flow {
             if (tree.body == null) {
                 return;
             }
-            /*  MemberEnter can generate synthetic methods, ignore them
+            /*  Ignore synthetic methods, except for translated lambda methods.
              */
-            if ((tree.sym.flags() & SYNTHETIC) != 0) {
+            if ((tree.sym.flags() & (SYNTHETIC | LAMBDA_METHOD)) == SYNTHETIC) {
                 return;
             }
 

langtools/src/share/classes/com/sun/tools/javac/comp/LambdaToMethod.java

@@ -30,6 +30,7 @@ import com.sun.tools.javac.tree.JCTree.JCMemberReference.ReferenceKind;
 import com.sun.tools.javac.tree.TreeMaker;
 import com.sun.tools.javac.tree.TreeTranslator;
 import com.sun.tools.javac.code.Attribute;
+import com.sun.tools.javac.code.Flags;
 import com.sun.tools.javac.code.Kinds;
 import com.sun.tools.javac.code.Scope;
 import com.sun.tools.javac.code.Symbol;
@@ -1315,7 +1316,9 @@ public class LambdaToMethod extends TreeTranslator {
                 ListBuffer<JCVariableDecl> paramBuff = new ListBuffer<JCVariableDecl>();
                 int i = 0;
                 for (List<Type> l = ptypes; l.nonEmpty(); l = l.tail) {
-                    paramBuff.append(make.Param(make.paramName(i++), l.head, owner));
+                    JCVariableDecl param = make.Param(make.paramName(i++), l.head, owner);
+                    param.sym.pos = tree.pos;
+                    paramBuff.append(param);
                 }
                 List<JCVariableDecl> params = paramBuff.toList();
 
@@ -1755,7 +1758,7 @@ public class LambdaToMethod extends TreeTranslator {
                         ((VarSymbol)ret).pos = ((VarSymbol)sym).pos;
                         break;
                     case CAPTURED_VAR:
-                        ret = new VarSymbol(SYNTHETIC | FINAL, name, types.erasure(sym.type), translatedSym) {
+                        ret = new VarSymbol(SYNTHETIC | FINAL | PARAMETER, name, types.erasure(sym.type), translatedSym) {
                             @Override
                             public Symbol baseSymbol() {
                                 //keep mapping with original captured symbol
@@ -1763,8 +1766,17 @@ public class LambdaToMethod extends TreeTranslator {
                             }
                         };
                         break;
+                    case LOCAL_VAR:
+                        ret = new VarSymbol(FINAL, name, types.erasure(sym.type), translatedSym);
+                        ((VarSymbol) ret).pos = ((VarSymbol) sym).pos;
+                        break;
+                    case PARAM:
+                        ret = new VarSymbol(FINAL | PARAMETER, name, types.erasure(sym.type), translatedSym);
+                        ((VarSymbol) ret).pos = ((VarSymbol) sym).pos;
+                        break;
                     default:
                         ret = makeSyntheticVar(FINAL, name, types.erasure(sym.type), translatedSym);
+                        ((VarSymbol) ret).pos = ((VarSymbol) sym).pos;
                 }
                 if (ret != sym) {
                     ret.setDeclarationAttributes(sym.getRawAttributes());
@@ -1845,7 +1857,7 @@ public class LambdaToMethod extends TreeTranslator {
                 // If instance access isn't needed, make it static.
                 // Interface instance methods must be default methods.
                 // Lambda methods are private synthetic.
-                translatedSym.flags_field = SYNTHETIC |
+                translatedSym.flags_field = SYNTHETIC | LAMBDA_METHOD |
                         PRIVATE |
                         (thisReferenced? (inInterface? DEFAULT : 0) : STATIC);
 

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

@@ -2892,7 +2892,8 @@ public class Gen extends JCTree.Visitor {
 
         @Override
         public void visitMethodDef(JCMethodDecl tree) {
-            if ((tree.sym.flags() & (SYNTHETIC | GENERATEDCONSTR)) != 0) {
+            if ((tree.sym.flags() & (SYNTHETIC | GENERATEDCONSTR)) != 0
+                    && (tree.sym.flags() & LAMBDA_METHOD) == 0) {
                 return;
             }
             if (tree.name.equals(names.clinit)) {
@@ -2906,6 +2907,7 @@ public class Gen extends JCTree.Visitor {
                 return;
             }
             currentMethod = tree.sym;
+
             super.visitMethodDef(tree);
         }
 

langtools/test/tools/javac/lambda/LocalVariableTable.java

@@ -0,0 +1,220 @@
+/*
+ * Copyright (c) 2013, 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 8025998 8026749
+ * @summary Missing LV table in lambda bodies
+ * @compile -g LocalVariableTable.java
+ * @run main LocalVariableTable
+ */
+
+import java.io.*;
+import java.lang.annotation.*;
+import java.util.*;
+import com.sun.tools.classfile.*;
+
+/*
+ * The test checks that a LocalVariableTable attribute is generated for the
+ * method bodies representing lambda expressions, and checks that the expected
+ * set of entries is found in the attribute.
+ *
+ * Since the bug was about missing entries in the LVT, not malformed entries,
+ * the test is not intended to be a detailed test of the contents of each
+ * LocalVariableTable entry: it is assumed that if a entry is present, it
+ * will have the correct contents.
+ *
+ * The test looks for test cases represented by nested classes whose
+ * name begins with "Lambda".  Each such class contains a lambda expression
+ * that will mapped into a lambda method, and because the test is compiled
+ * with -g, these methods should have a LocalVariableTable.  The set of
+ * expected names in the LVT is provided in an annotation on the class for
+ * the test case.
+ */
+public class LocalVariableTable {
+    public static void main(String... args) throws Exception {
+        new LocalVariableTable().run();
+    }
+
+    void run() throws Exception {
+        // the declared classes are returned in an unspecified order,
+        // so for neatness, sort them by name before processing them
+        Class<?>[] classes = getClass().getDeclaredClasses();
+        Arrays.sort(classes, (c1, c2) -> c1.getName().compareTo(c2.getName()));
+
+        for (Class<?> c : classes) {
+            if (c.getSimpleName().startsWith("Lambda"))
+                check(c);
+        }
+        if (errors > 0)
+            throw new Exception(errors + " errors found");
+    }
+
+    /** Check an individual test case. */
+    void check(Class<?> c) throws Exception {
+        System.err.println("Checking " + c.getSimpleName());
+
+        Expect expect = c.getAnnotation(Expect.class);
+        if (expect == null) {
+            error("@Expect not found for class " + c.getSimpleName());
+            return;
+        }
+
+        ClassFile cf = ClassFile.read(getClass().getResource(c.getName() + ".class").openStream());
+        Method m = getLambdaMethod(cf);
+        if (m == null) {
+            error("lambda method not found");
+            return;
+        }
+
+        Code_attribute code = (Code_attribute) m.attributes.get(Attribute.Code);
+        if (code == null) {
+            error("Code attribute not found");
+            return;
+        }
+
+        LocalVariableTable_attribute lvt =
+                (LocalVariableTable_attribute) code.attributes.get(Attribute.LocalVariableTable);
+        if (lvt == null) {
+            error("LocalVariableTable attribute not found");
+            return;
+        }
+
+        Set<String> foundNames = new LinkedHashSet<>();
+        for (LocalVariableTable_attribute.Entry e: lvt.local_variable_table) {
+            foundNames.add(cf.constant_pool.getUTF8Value(e.name_index));
+        }
+
+        Set<String> expectNames = new LinkedHashSet<>(Arrays.asList(expect.value()));
+        if (!foundNames.equals(expectNames)) {
+            Set<String> foundOnly = new LinkedHashSet<>(foundNames);
+            foundOnly.removeAll(expectNames);
+            for (String s: foundOnly)
+                error("Unexpected name found: " + s);
+            Set<String> expectOnly = new LinkedHashSet<>(expectNames);
+            expectOnly.removeAll(foundNames);
+            for (String s: expectOnly)
+                error("Expected name not found: " + s);
+        }
+    }
+
+    /** Get a method whose name begins "lambda$...". */
+    Method getLambdaMethod(ClassFile cf) throws ConstantPoolException {
+        for (Method m: cf.methods) {
+            if (m.getName(cf.constant_pool).startsWith("lambda$"))
+                return m;
+        }
+        return null;
+    }
+
+    /** Report an error. */
+    void error(String msg) {
+        System.err.println("Error: " + msg);
+        errors++;
+    }
+
+    int errors;
+
+    /**
+     * Annotation used to provide the set of names expected in the LVT attribute.
+     */
+    @Retention(RetentionPolicy.RUNTIME)
+    @interface Expect {
+        String[] value();
+    }
+
+    /** Functional interface with nullary method. */
+    interface Run0 {
+        public void run();
+    }
+
+    /** Functional interface with 1-ary method. */
+    interface Run1 {
+        public void run(int a0);
+    }
+
+    /** Functional interface with 2-ary method. */
+    interface Run2 {
+        public void run(int a0, int a1);
+    }
+
+    /*
+     * ---------- Test cases ---------------------------------------------------
+     */
+
+    @Expect({ "x" })
+    static class Lambda_Args0_Local1 {
+        Run0 r = () -> { int x = 0; };
+    }
+
+    @Expect({ "x", "this" })
+    static class Lambda_Args0_Local1_this {
+        int v;
+        Run0 r = () -> { int x = v; };
+    }
+
+    @Expect({ "a" })
+    static class Lambda_Args1_Local0 {
+        Run1 r = (a) -> { };
+    }
+
+    @Expect({ "a", "x" })
+    static class Lambda_Args1_Local1 {
+        Run1 r = (a) -> { int x = a; };
+    }
+
+    @Expect({ "a", "x" })
+    static class Lambda_Args1_Local1_Captured1 {
+        void m() {
+            int v = 0;
+            Run1 r = (a) -> { int x = a + v; };
+        }
+    }
+
+    @Expect({ "a1", "a2", "x1", "x2", "this" })
+    static class Lambda_Args2_Local2_Captured2_this {
+        int v;
+        void m() {
+            int v1 = 0;
+            int v2 = 0;
+            Run2 r = (a1, a2) -> {
+                int x1 = a1 + v1 + v;
+                int x2 = a2 + v2 + v;
+            };
+        }
+    }
+
+    @Expect({ "e" })
+    static class Lambda_Try_Catch {
+        private static Runnable asUncheckedRunnable(Closeable c) {
+            return () -> {
+                try {
+                    c.close();
+                } catch (IOException e) {
+                   throw new UncheckedIOException(e);
+                }
+            };
+        }
+    }
+}
+