7175538: Integrate efectively final check with DA/DU analysis

Summary: Allow generalized effectively-final analysis for all local variables
Reviewed-by: jjg, dlsmith

src/share/classes/com/sun/tools/javac/code/Source.java

@@ -200,6 +200,9 @@ public enum Source {
     public boolean allowMethodReferences() {
         return compareTo(JDK1_8) >= 0;
     }
+    public boolean allowEffectivelyFinalInInnerClasses() {
+        return compareTo(JDK1_8) >= 0;
+    }
     public static SourceVersion toSourceVersion(Source source) {
         switch(source) {
         case JDK1_2:

src/share/classes/com/sun/tools/javac/comp/Attr.java

@@ -228,7 +228,7 @@ public class Attr extends JCTree.Visitor {
      *  @param env    The current environment.
      */
     boolean isAssignableAsBlankFinal(VarSymbol v, Env<AttrContext> env) {
-        Symbol owner = env.info.scope.owner;
+        Symbol owner = owner(env);
            // owner refers to the innermost variable, method or
            // initializer block declaration at this point.
         return
@@ -243,6 +243,41 @@ public class Attr extends JCTree.Visitor {
              ((v.flags() & STATIC) != 0) == Resolve.isStatic(env));
     }
 
+    /**
+     * Return the innermost enclosing owner symbol in a given attribution context
+     */
+    Symbol owner(Env<AttrContext> env) {
+        while (true) {
+            switch (env.tree.getTag()) {
+                case VARDEF:
+                    //a field can be owner
+                    VarSymbol vsym = ((JCVariableDecl)env.tree).sym;
+                    if (vsym.owner.kind == TYP) {
+                        return vsym;
+                    }
+                    break;
+                case METHODDEF:
+                    //method def is always an owner
+                    return ((JCMethodDecl)env.tree).sym;
+                case CLASSDEF:
+                    //class def is always an owner
+                    return ((JCClassDecl)env.tree).sym;
+                case BLOCK:
+                    //static/instance init blocks are owner
+                    Symbol blockSym = env.info.scope.owner;
+                    if ((blockSym.flags() & BLOCK) != 0) {
+                        return blockSym;
+                    }
+                    break;
+                case TOPLEVEL:
+                    //toplevel is always an owner (for pkge decls)
+                    return env.info.scope.owner;
+            }
+            Assert.checkNonNull(env.next);
+            env = env.next;
+        }
+    }
+
     /** Check that variable can be assigned to.
      *  @param pos    The current source code position.
      *  @param v      The assigned varaible
@@ -883,7 +918,6 @@ public class Attr extends JCTree.Visitor {
                 memberEnter.memberEnter(tree, env);
                 annotate.flush();
             }
-            tree.sym.flags_field |= EFFECTIVELY_FINAL;
         }
 
         VarSymbol v = tree.sym;
@@ -2187,16 +2221,6 @@ public class Attr extends JCTree.Visitor {
             // illegal forward reference.
             checkInit(tree, env, v, false);
 
-            // If symbol is a local variable accessed from an embedded
-            // inner class check that it is final.
-            if (v.owner.kind == MTH &&
-                v.owner != env.info.scope.owner &&
-                (v.flags_field & FINAL) == 0) {
-                log.error(tree.pos(),
-                          "local.var.accessed.from.icls.needs.final",
-                          v);
-            }
-
             // If we are expecting a variable (as opposed to a value), check
             // that the variable is assignable in the current environment.
             if (pkind() == VAR)
@@ -2590,7 +2614,7 @@ public class Attr extends JCTree.Visitor {
             // and are subject to definite assignment checking.
             if ((env.info.enclVar == v || v.pos > tree.pos) &&
                 v.owner.kind == TYP &&
-                canOwnInitializer(env.info.scope.owner) &&
+                canOwnInitializer(owner(env)) &&
                 v.owner == env.info.scope.owner.enclClass() &&
                 ((v.flags() & STATIC) != 0) == Resolve.isStatic(env) &&
                 (!env.tree.hasTag(ASSIGN) ||

src/share/classes/com/sun/tools/javac/parser/JavacParser.java

@@ -113,9 +113,9 @@ public class JavacParser implements Parser {
         this.allowMulticatch = source.allowMulticatch();
         this.allowStringFolding = fac.options.getBoolean("allowStringFolding", true);
         this.allowLambda = source.allowLambda() &&
-                fac.options.isSet("allowLambda");
+                fac.options.isSet("allowLambda"); //pre-lambda guard
         this.allowMethodReferences = source.allowMethodReferences() &&
-                fac.options.isSet("allowMethodReferences");
+                fac.options.isSet("allowMethodReferences"); //pre-lambda guard
         this.keepDocComments = keepDocComments;
         docComments = newDocCommentTable(keepDocComments);
         this.keepLineMap = keepLineMap;

src/share/classes/com/sun/tools/javac/resources/compiler.properties

@@ -168,6 +168,14 @@ compiler.err.cant.apply.symbols=\
 compiler.err.cant.assign.val.to.final.var=\
     cannot assign a value to final variable {0}
 
+# 0: symbol, 1: message segment
+compiler.err.cant.ref.non.effectively.final.var=\
+    local variables referenced from {1} must be final or effectively final
+
+
+compiler.misc.inner.cls=\
+    an inner class
+
 # 0: type
 compiler.err.cant.deref=\
     {0} cannot be dereferenced

test/tools/javac/diags/examples/CantRefNonEffectivelyFinalVar.java

+/*
+ * Copyright (c) 2012, 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.
+ */
+
+// key: compiler.err.cant.ref.non.effectively.final.var
+// key: compiler.misc.inner.cls
+// options: -XDallowEffectivelyFinalInInnerClasses
+
+class CantRefNonEffectivelyFinalVar {
+    void test() {
+        int i = 0;
+        new Object() { int j = i; };
+        i = 2;
+    }
+}

test/tools/javac/lambda/EffectivelyFinalTest.java

+/*
+ * Copyright (c) 2012, 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
+ * @summary Integrate efectively final check with DA/DU analysis
+ * @compile/fail/ref=EffectivelyFinalTest01.out -XDallowEffectivelyFinalInInnerClasses -XDrawDiagnostics EffectivelyFinalTest.java
+ * @compile/fail/ref=EffectivelyFinalTest02.out -source 7 -Xlint:-options -XDrawDiagnostics EffectivelyFinalTest.java
+ */
+class EffectivelyFinalTest {
+
+    void m1(int x) {
+        int y = 1;
+        new Object() { { System.out.println(x+y); } }; //ok - both x and y are EF
+    }
+
+    void m2(int x) {
+        int y;
+        y = 1;
+        new Object() { { System.out.println(x+y); } }; //ok - both x and y are EF
+    }
+
+    void m3(int x, boolean cond) {
+        int y;
+        if (cond) y = 1;
+        new Object() { { System.out.println(x+y); } }; //error - y not DA
+    }
+
+    void m4(int x, boolean cond) {
+        int y;
+        if (cond) y = 1;
+        else y = 2;
+        new Object() { { System.out.println(x+y); } }; //ok - both x and y are EF
+    }
+
+    void m5(int x, boolean cond) {
+        int y;
+        if (cond) y = 1;
+        y = 2;
+        new Object() { { System.out.println(x+y); } }; //error - y not EF
+    }
+
+    void m6(int x) {
+        new Object() { { System.out.println(x+1); } }; //error - x not EF
+        x++;
+    }
+
+    void m7(int x) {
+        new Object() { { System.out.println(x=1); } }; //error - x not EF
+    }
+
+    void m8() {
+        int y;
+        new Object() { { System.out.println(y=1); } }; //error - y not EF
+    }
+}

test/tools/javac/lambda/EffectivelyFinalTest01.out

+EffectivelyFinalTest.java:46:47: compiler.err.var.might.not.have.been.initialized: y
+EffectivelyFinalTest.java:60:47: compiler.err.cant.ref.non.effectively.final.var: y, (compiler.misc.inner.cls)
+EffectivelyFinalTest.java:64:45: compiler.err.cant.ref.non.effectively.final.var: x, (compiler.misc.inner.cls)
+EffectivelyFinalTest.java:69:45: compiler.err.cant.ref.non.effectively.final.var: x, (compiler.misc.inner.cls)
+EffectivelyFinalTest.java:74:45: compiler.err.cant.ref.non.effectively.final.var: y, (compiler.misc.inner.cls)
+5 errors

test/tools/javac/lambda/EffectivelyFinalTest02.out

+EffectivelyFinalTest.java:46:47: compiler.err.var.might.not.have.been.initialized: y
+EffectivelyFinalTest.java:34:45: compiler.err.local.var.accessed.from.icls.needs.final: x
+EffectivelyFinalTest.java:34:47: compiler.err.local.var.accessed.from.icls.needs.final: y
+EffectivelyFinalTest.java:40:45: compiler.err.local.var.accessed.from.icls.needs.final: x
+EffectivelyFinalTest.java:40:47: compiler.err.local.var.accessed.from.icls.needs.final: y
+EffectivelyFinalTest.java:46:45: compiler.err.local.var.accessed.from.icls.needs.final: x
+EffectivelyFinalTest.java:53:45: compiler.err.local.var.accessed.from.icls.needs.final: x
+EffectivelyFinalTest.java:53:47: compiler.err.local.var.accessed.from.icls.needs.final: y
+EffectivelyFinalTest.java:60:45: compiler.err.local.var.accessed.from.icls.needs.final: x
+EffectivelyFinalTest.java:60:47: compiler.err.local.var.accessed.from.icls.needs.final: y
+EffectivelyFinalTest.java:64:45: compiler.err.local.var.accessed.from.icls.needs.final: x
+EffectivelyFinalTest.java:69:45: compiler.err.local.var.accessed.from.icls.needs.final: x
+EffectivelyFinalTest.java:74:45: compiler.err.local.var.accessed.from.icls.needs.final: y
+13 errors