tools/tree/MethodExpression.java

/*
 * Copyright (c) 1994, 2003, 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.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * 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
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 * questions.
 */

package sun.tools.tree;

import sun.tools.java.*;
import sun.tools.asm.Assembler;
import java.io.PrintStream;
import java.util.Hashtable;

/**
 * WARNING: The contents of this source file are not part of any
 * supported API.  Code that depends on them does so at its own risk:
 * they are subject to change or removal without notice.
 */
public
class MethodExpression extends NaryExpression {
    Identifier id;
    ClassDefinition clazz;   // The class in which the called method is defined
    MemberDefinition field;
    Expression implementation;

    private boolean isSuper;  // Set if qualified by 'super' or '<class>.super'.

    /**
     * constructor
     */
    public MethodExpression(long where, Expression right, Identifier id, Expression args[]) {
        super(METHOD, where, Type.tError, right, args);
        this.id = id;
    }
    public MethodExpression(long where, Expression right, MemberDefinition field, Expression args[]) {
        super(METHOD, where, field.getType().getReturnType(), right, args);
        this.id = field.getName();
        this.field = field;
        this.clazz = field.getClassDefinition();
    }

    // This is a hack used only within certain access methods generated by
    // 'SourceClass.getAccessMember'.  It allows an 'invokespecial' instruction
    // to be forced even though 'super' does not appear within the call.
    // Such access methods are needed for access to protected methods when using
    // the qualified '<class>.super.<method>(...)' notation.
    public MethodExpression(long where, Expression right,
                            MemberDefinition field, Expression args[], boolean forceSuper) {
        this(where, right, field, args);
        this.isSuper = forceSuper;
    }

    public Expression getImplementation() {
        if (implementation != null)
            return implementation;
        return this;
    }

    /**
     * Check expression type
     */
    public Vset checkValue(Environment env, Context ctx, Vset vset, Hashtable<Object, Object> exp) {
        ClassDeclaration c = null;
        boolean isArray = false;
        boolean staticRef = false;

        // Access method to use if required.
        MemberDefinition implMethod = null;

        ClassDefinition ctxClass = ctx.field.getClassDefinition();

        // When calling a constructor, we may need to add an
        // additional argument to transmit the outer instance link.
        Expression args[] = this.args;
        if (id.equals(idInit)){
            ClassDefinition conCls = ctxClass;
            try {
                Expression conOuter = null;
                if (right instanceof SuperExpression) {
                    // outer.super(...)
                    conCls = conCls.getSuperClass().getClassDefinition(env);
                    conOuter = ((SuperExpression)right).outerArg;
                } else if (right instanceof ThisExpression) {
                    // outer.this(...)
                    conOuter = ((ThisExpression)right).outerArg;
                }
                args = NewInstanceExpression.
                    insertOuterLink(env, ctx, where, conCls, conOuter, args);
            } catch (ClassNotFound ee) {
                // the same error is handled elsewhere
            }
        }

        Type argTypes[] = new Type[args.length];

        // The effective accessing class, for access checking.
        // This is normally the immediately enclosing class.
        ClassDefinition sourceClass = ctxClass;

        try {
            if (right == null) {
                staticRef = ctx.field.isStatic();
                // Find the first outer scope that mentions the method.
                ClassDefinition cdef = ctxClass;
                MemberDefinition m = null;
                for (; cdef != null; cdef = cdef.getOuterClass()) {
                    m = cdef.findAnyMethod(env, id);
                    if (m != null) {
                        break;
                    }
                }
                if (m == null) {
                    // this is the scope for error diagnosis
                    c = ctx.field.getClassDeclaration();
                } else {
                    // found the innermost scope in which m occurs
                    c = cdef.getClassDeclaration();

                    // Maybe an inherited method hides an apparent method.
                    // Keep looking at enclosing scopes to find out.
                    if (m.getClassDefinition() != cdef) {
                        ClassDefinition cdef2 = cdef;
                        while ((cdef2 = cdef2.getOuterClass()) != null) {
                            MemberDefinition m2 = cdef2.findAnyMethod(env, id);
                            if (m2 != null && m2.getClassDefinition() == cdef2) {
                                env.error(where, "inherited.hides.method",
                                          id, cdef.getClassDeclaration(),
                                          cdef2.getClassDeclaration());
                                break;
                            }
                        }
                    }
                }
            } else {
                if (id.equals(idInit)) {
                    int thisN = ctx.getThisNumber();
                    if (!ctx.field.isConstructor()) {
                        env.error(where, "invalid.constr.invoke");
                        return vset.addVar(thisN);
                    }
                    // As a consequence of the DA/DU rules in the JLS (draft of
                    // forthcoming 2e), all variables are both definitely assigned
                    // and definitely unassigned in unreachable code.  Normally, this
                    // correctly suppresses DA/DU-related errors in such code.
                    // The use of the DA status of the 'this' variable for the extra
                    // check below on correct constructor usage, however, does not quite
                    // fit into this DA/DU scheme.  The current representation of
                    // Vsets for unreachable dead-ends, does not allow 'clearVar'
                    // to work, as the DA/DU bits (all on) are implicitly represented
                    // by the fact that the Vset is a dead-end.  The DA/DU status
                    // of the 'this' variable is supposed to be temporarily
                    // cleared at the beginning of a constructor and during the
                    // checking of constructor arguments (see below in this method).
                    // Since 'clearVar' has no effect on dead-ends, we may
                    // find the 'this' variable in an erroneously definitely-assigned state.
                    // As a workaround, we suppress the following error message when
                    // the Vset is a dead-end, i.e., when we are in unreachable code.
                    // Unfortunately, the special-case treatment of reachability for
                    // if-then and if-then-else allows unreachable code in some circumstances,
                    // thus it is possible that no error message will be emitted at all.
                    // While this behavior is strictly incorrect (thus we call this a
                    // workaround), the problematic code is indeed unreachable and will
                    // not be executed.  In fact, it will be entirely omitted from the
                    // translated program, and can cause no harm at runtime.  A correct
                    // solution would require modifying the representation of the DA/DU
                    // analysis to use finite Vsets only, restricting the universe
                    // of variables about which assertions are made (even in unreachable
                    // code) to variables that are actually in scope. Alternatively, the
                    // Vset extension and the dead-end marker (currently a reserved value
                    // of the extension) could be represented orthogonally.  In either case,
                    // 'clearVar' could then be made to work on (non-canonical) dead ends.
                    // See file 'Vset.java'.
                    if (!vset.isReallyDeadEnd() && vset.testVar(thisN)) {
                        env.error(where, "constr.invoke.not.first");
                        return vset;
                    }
                    vset = vset.addVar(thisN);
                    if (right instanceof SuperExpression) {
                        // supers require this specific kind of checking
                        vset = right.checkAmbigName(env, ctx, vset, exp, this);
                    } else {
                        vset = right.checkValue(env, ctx, vset, exp);
                    }
                } else {
                    vset = right.checkAmbigName(env, ctx, vset, exp, this);
                    if (right.type == Type.tPackage) {
                        FieldExpression.reportFailedPackagePrefix(env, right);
                        return vset;
                    }
                    if (right instanceof TypeExpression) {
                        staticRef = true;
                    }
                }
                if (right.type.isType(TC_CLASS)) {
                    c = env.getClassDeclaration(right.type);
                } else if (right.type.isType(TC_ARRAY)) {
                    isArray = true;
                    c = env.getClassDeclaration(Type.tObject);
                } else {
                    if (!right.type.isType(TC_ERROR)) {
                        env.error(where, "invalid.method.invoke", right.type);
                    }
                    return vset;
                }

                // Normally, the effective accessing class is the innermost
                // class surrounding the current method call, but, for calls
                // of the form '<class>.super.<method>(...)', it is <class>.
                // This allows access to protected members of a superclass
                // from within a class nested within one of its subclasses.
                // Otherwise, for example, the call below to 'matchMethod'
                // may fail due to the rules for visibility of inaccessible
                // members.  For consistency, we treat qualified 'this' in
                // the same manner, as error diagnostics will be affected.
                // QUERY: Are there subtle unexplored language issues here?
                if (right instanceof FieldExpression) {
                    Identifier id = ((FieldExpression)right).id;
                    if (id == idThis) {
                        sourceClass = ((FieldExpression)right).clazz;
                    } else if (id == idSuper) {
                        isSuper = true;
                        sourceClass = ((FieldExpression)right).clazz;
                    }
                } else if (right instanceof SuperExpression) {
                    isSuper = true;
                }

                // Fix for 4158650.  When we extend a protected inner
                // class in a different package, we may not have access
                // to the type of our superclass.  Allow the call to
                // the superclass constructor from within our constructor
                // Note that this check does not apply to constructor
                // calls in new instance expressions -- those are part
                // of NewInstanceExpression#check().
                if (id != idInit) {
                    // Required by JLS 6.6.1.  Fixes 4143715.
                    // (See also 4094658.)
                    if (!FieldExpression.isTypeAccessible(where, env,
                                                          right.type,
                                                          sourceClass)) {
                        ClassDeclaration cdecl =
                            sourceClass.getClassDeclaration();
                        if (staticRef) {
                            env.error(where, "no.type.access",
                                      id, right.type.toString(), cdecl);
                        } else {
                            env.error(where, "cant.access.member.type",
                                      id, right.type.toString(), cdecl);
                        }
                    }
                }
            }

            // Compose a list of argument types
            boolean hasErrors = false;

            // "this" is not defined during argument checking
            if (id.equals(idInit)) {
                vset = vset.clearVar(ctx.getThisNumber());
            }

            for (int i = 0 ; i < args.length ; i++) {
                vset = args[i].checkValue(env, ctx, vset, exp);
                argTypes[i] = args[i].type;
                hasErrors = hasErrors || argTypes[i].isType(TC_ERROR);
            }

            // "this" is defined after the constructor invocation
            if (id.equals(idInit)) {
                vset = vset.addVar(ctx.getThisNumber());
            }

            // Check if there are any type errors in the arguments
            if (hasErrors) {
                return vset;
            }

            // Get the method field, given the argument types
            clazz = c.getClassDefinition(env);

            if (field == null) {

                field = clazz.matchMethod(env, sourceClass, id, argTypes);

                if (field == null) {
                    if (id.equals(idInit)) {
                        if (diagnoseMismatch(env, args, argTypes))
                            return vset;
                        String sig = clazz.getName().getName().toString();
                        sig = Type.tMethod(Type.tError, argTypes).typeString(sig, false, false);
                        env.error(where, "unmatched.constr", sig, c);
                        return vset;
                    }
                    String sig = id.toString();
                    sig = Type.tMethod(Type.tError, argTypes).typeString(sig, false, false);
                    if (clazz.findAnyMethod(env, id) == null) {
                        if (ctx.getField(env, id) != null) {
                            env.error(where, "invalid.method", id, c);
                        } else {
                            env.error(where, "undef.meth", sig, c);
                        }
                    } else if (diagnoseMismatch(env, args, argTypes)) {
                    } else {
                        env.error(where, "unmatched.meth", sig, c);
                    }
                    return vset;
                }

            }

            type = field.getType().getReturnType();

            // Make sure that static references are allowed
            if (staticRef && !field.isStatic()) {
                env.error(where, "no.static.meth.access",
                          field, field.getClassDeclaration());
                return vset;
            }

            if (field.isProtected()
                && !(right == null)
                && !(right instanceof SuperExpression
                     // Extension of JLS 6.6.2 for qualified 'super'.
                     || (right instanceof FieldExpression &&
                         ((FieldExpression)right).id == idSuper))
                && !sourceClass.protectedAccess(env, field, right.type)) {
                env.error(where, "invalid.protected.method.use",
                          field.getName(), field.getClassDeclaration(),
                          right.type);
                return vset;
            }

            // In <class>.super.<method>(), we cannot simply evaluate
            // <class>.super to an object reference (as we would for
            // <class>.super.<field>) and then perform an 'invokespecial'.
            // An 'invokespecial' must be performed from within (a subclass of)
            // the class in which the target method is located.
            if (right instanceof FieldExpression &&
                ((FieldExpression)right).id == idSuper) {
                if (!field.isPrivate()) {
                    // The private case is handled below.
                    // Use an access method unless the effective accessing class
                    // (the class qualifying the 'super') is the same as the
                    // immediately enclosing class, i.e., the qualification was
                    // unnecessary.
                    if (sourceClass != ctxClass) {
                        implMethod = sourceClass.getAccessMember(env, ctx, field, true);
                    }
                }
            }

            // Access method for private field if not in the same class.
            if (implMethod == null && field.isPrivate()) {
                ClassDefinition cdef = field.getClassDefinition();
                if (cdef != ctxClass) {
                    implMethod = cdef.getAccessMember(env, ctx, field, false);
                }
            }

            // Make sure that we are not invoking an abstract method
            if (field.isAbstract() && (right != null) && (right.op == SUPER)) {
                env.error(where, "invoke.abstract", field, field.getClassDeclaration());
                return vset;
            }

            if (field.reportDeprecated(env)) {
                if (field.isConstructor()) {
                    env.error(where, "warn.constr.is.deprecated", field);
                } else {
                    env.error(where, "warn.meth.is.deprecated",
                              field, field.getClassDefinition());
                }
            }

            // Check for recursive constructor
            if (field.isConstructor() && ctx.field.equals(field)) {
                env.error(where, "recursive.constr", field);
            }

            // When a package-private class defines public or protected
            // members, those members may sometimes be accessed from
            // outside of the package in public subclasses.  In these
            // cases, we need to massage the method call to refer to
            // to an accessible subclass rather than the package-private
            // parent class.  Part of fix for 4135692.

            // Find out if the class which contains this method
            // call has access to the class which declares the
            // public or protected method referent.
            // We don't perform this translation on constructor calls.
            if (sourceClass == ctxClass) {
                ClassDefinition declarer = field.getClassDefinition();
                if (!field.isConstructor() &&
                    declarer.isPackagePrivate() &&
                    !declarer.getName().getQualifier()
                    .equals(sourceClass.getName().getQualifier())) {

                    //System.out.println("The access of member " +
                    //             field + " declared in class " +
                    //             declarer +
                    //             " is not allowed by the VM from class  " +
                    //             accessor +
                    //             ".  Replacing with an access of class " +
                    //             clazz);

                    // We cannot make this access at the VM level.
                    // Construct a member which will stand for this
                    // method in clazz and set `field' to refer to it.
                    field =
                        MemberDefinition.makeProxyMember(field, clazz, env);
                }
            }

            sourceClass.addDependency(field.getClassDeclaration());
            if (sourceClass != ctxClass) {
                ctxClass.addDependency(field.getClassDeclaration());
            }

        } catch (ClassNotFound ee) {
            env.error(where, "class.not.found", ee.name, ctx.field);
            return vset;

        } catch (AmbiguousMember ee) {
            env.error(where, "ambig.field", id, ee.field1, ee.field2);
            return vset;
        }

        // Make sure it is qualified
        if ((right == null) && !field.isStatic()) {
            right = ctx.findOuterLink(env, where, field);
            vset = right.checkValue(env, ctx, vset, exp);
        }

        // Cast arguments
        argTypes = field.getType().getArgumentTypes();
        for (int i = 0 ; i < args.length ; i++) {
            args[i] = convert(env, ctx, argTypes[i], args[i]);
        }

        if (field.isConstructor()) {
            MemberDefinition m = field;
            if (implMethod != null) {
                m = implMethod;
            }
            int nargs = args.length;
            Expression[] newargs = args;
            if (nargs > this.args.length) {
                // Argument was added above.
                // Maintain the model for hidden outer args in outer.super(...):
                Expression rightI;
                if (right instanceof SuperExpression) {
                    rightI = new SuperExpression(right.where, ctx);
                    ((SuperExpression)right).outerArg = args[0];
                } else if (right instanceof ThisExpression) {
                    rightI = new ThisExpression(right.where, ctx);
                } else {
                    throw new CompilerError("this.init");
                }
                if (implMethod != null) {
                    // Need dummy argument for access method.
                    // Dummy argument follows outer instance link.
                    // Leave 'this.args' equal to 'newargs' but
                    // without the outer instance link.
                    newargs = new Expression[nargs+1];
                    this.args = new Expression[nargs];
                    newargs[0] = args[0]; // outer instance
                    this.args[0] = newargs[1] = new NullExpression(where); // dummy argument
                    for (int i = 1 ; i < nargs ; i++) {
                        this.args[i] = newargs[i+1] = args[i];
                    }
                } else {
                    // Strip outer instance link from 'this.args'.
                    // ASSERT(this.arg.length == nargs-1);
                    for (int i = 1 ; i < nargs ; i++) {
                        this.args[i-1] = args[i];
                    }
                }
                implementation = new MethodExpression(where, rightI, m, newargs);
                implementation.type = type; // Is this needed?
            } else {
                // No argument was added.
                if (implMethod != null) {
                    // Need dummy argument for access method.
                    // Dummy argument is first, as there is no outer instance link.
                    newargs = new Expression[nargs+1];
                    newargs[0] = new NullExpression(where);
                    for (int i = 0 ; i < nargs ; i++) {
                        newargs[i+1] = args[i];
                    }
                }
                implementation = new MethodExpression(where, right, m, newargs);
            }
        } else {
            // Have ordinary method.
            // Argument should have been added only for a constructor.
            if (args.length > this.args.length) {
                throw new CompilerError("method arg");
            }
            if (implMethod != null) {
                //System.out.println("Calling " + field + " via " + implMethod);
                Expression oldargs[] = this.args;
                if (field.isStatic()) {
                    Expression call = new MethodExpression(where, null, implMethod, oldargs);
                    implementation = new CommaExpression(where, right, call);
                } else {
                    // Access method needs an explicit 'this' pointer.
                    int nargs = oldargs.length;
                    Expression newargs[] = new Expression[nargs+1];
                    newargs[0] = right;
                    for (int i = 0; i < nargs; i++) {
                        newargs[i+1] = oldargs[i];
                    }
                    implementation = new MethodExpression(where, null, implMethod, newargs);
                }
            }
        }

        // Follow super() by variable initializations
        if (ctx.field.isConstructor() &&
            field.isConstructor() && (right != null) && (right.op == SUPER)) {
            Expression e = makeVarInits(env, ctx);
            if (e != null) {
                if (implementation == null)
                    implementation = (Expression)this.clone();
                implementation = new CommaExpression(where, implementation, e);
            }
        }

        // Throw the declared exceptions.
        ClassDeclaration exceptions[] = field.getExceptions(env);
        if (isArray && (field.getName() == idClone) &&
               (field.getType().getArgumentTypes().length == 0)) {
            /* Arrays pretend that they have "public Object clone()" that doesn't
             * throw anything, according to the language spec.
             */
            exceptions = new ClassDeclaration[0];
            /* See if there's a bogus catch for it, to issue a warning. */
            for (Context p = ctx; p != null; p = p.prev) {
                if (p.node != null && p.node.op == TRY) {
                    ((TryStatement) p.node).arrayCloneWhere = where;
                }
            }
        }
        for (int i = 0 ; i < exceptions.length ; i++) {
            if (exp.get(exceptions[i]) == null) {
                exp.put(exceptions[i], this);
            }
        }

        // Mark all blank finals as definitely assigned following 'this(...)'.
        // Correctness follows inductively from the requirement that all blank finals
        // be definitely assigned at the completion of every constructor.
        if (ctx.field.isConstructor() &&
            field.isConstructor() && (right != null) && (right.op == THIS)) {
            ClassDefinition cls = field.getClassDefinition();
            for (MemberDefinition f = cls.getFirstMember() ; f != null ; f = f.getNextMember()) {
                if (f.isVariable() && f.isBlankFinal() && !f.isStatic()) {
                    // Static variables should also be considered defined as well, but this
                    // is handled in 'SourceClass.checkMembers', and we should not interfere.
                    vset = vset.addVar(ctx.getFieldNumber(f));
                }
            }
        }

        return vset;
    }

    /**
     * Check void expression
     */
    public Vset check(Environment env, Context ctx, Vset vset, Hashtable<Object, Object> exp) {
        return checkValue(env, ctx, vset, exp);
    }

    /**
     * We're about to report a "unmatched method" error.
     * Try to issue a better diagnostic by comparing the actual argument types
     * with the method (or methods) available.
     * In particular, if there is an argument which fails to match <em>any</em>
     * method, we report a type mismatch error against that particular argument.
     * The diagnostic will report a target type taken from one of the methods.
     * <p>
     * Return false if we couldn't think of anything smart to say.
     */
    boolean diagnoseMismatch(Environment env, Expression args[],
                             Type argTypes[]) throws ClassNotFound {
        Type margType[] = new Type[1];
        boolean saidSomething = false;
        int start = 0;
        while (start < argTypes.length) {
            int code = clazz.diagnoseMismatch(env, id, argTypes, start, margType);
            String opName = (id.equals(idInit)) ? "constructor" : opNames[op];
            if (code == -2) {
                env.error(where, "wrong.number.args", opName);
                saidSomething = true;
            }
            if (code < 0)  break;
            int i = code >> 2;
            boolean castOK = (code & 2) != 0;
            boolean ambig = (code & 1) != 0;
            Type targetType = margType[0];

            // At least one argument is offensive to all overloadings.
            // targetType is one of the argument types it does not match.
            String ttype = ""+targetType;

            // The message might be slightly misleading, if there are other
            // argument types that also would match.  Hint at this:
            //if (ambig)  ttype = "{"+ttype+";...}";

            if (castOK)
                env.error(args[i].where, "explicit.cast.needed", opName, argTypes[i], ttype);
            else
                env.error(args[i].where, "incompatible.type", opName, argTypes[i], ttype);
            saidSomething = true;
            start = i+1;        // look for other bad arguments, too
        }
        return saidSomething;
    }

    /**
     * Inline
     */
    static final int MAXINLINECOST = Statement.MAXINLINECOST;

    private
    Expression inlineMethod(Environment env, Context ctx, Statement s, boolean valNeeded) {
        if (env.dump()) {
            System.out.println("INLINE METHOD " + field + " in " + ctx.field);
        }
        LocalMember v[] = LocalMember.copyArguments(ctx, field);
        Statement body[] = new Statement[v.length + 2];

        int n = 0;
        if (field.isStatic()) {
            body[0] = new ExpressionStatement(where, right);
        } else {
            if ((right != null) && (right.op == SUPER)) {
                right = new ThisExpression(right.where, ctx);
            }
            body[0] = new VarDeclarationStatement(where, v[n++], right);
        }
        for (int i = 0 ; i < args.length ; i++) {
            body[i + 1] = new VarDeclarationStatement(where, v[n++], args[i]);
        }
        //System.out.print("BEFORE:"); s.print(System.out); System.out.println();
        // Note: If !valNeeded, then all returns in the body of the method
        // change to void returns.
        body[body.length - 1] = (s != null) ? s.copyInline(ctx, valNeeded) : null;
        //System.out.print("COPY:"); body[body.length - 1].print(System.out); System.out.println();
        LocalMember.doneWithArguments(ctx, v);

        // Make sure the type matches what the return statements are returning.
        Type type = valNeeded ? this.type : Type.tVoid;
        Expression e = new InlineMethodExpression(where, type, field, new CompoundStatement(where, body));
        return valNeeded ? e.inlineValue(env, ctx) : e.inline(env, ctx);
    }

    public Expression inline(Environment env, Context ctx) {
        if (implementation != null)
            return implementation.inline(env, ctx);
        try {
            if (right != null) {
                right = field.isStatic() ? right.inline(env, ctx) : right.inlineValue(env, ctx);
            }
            for (int i = 0 ; i < args.length ; i++) {
                args[i] = args[i].inlineValue(env, ctx);
            }

            // ctxClass is the current class trying to inline this method
            ClassDefinition ctxClass = ctx.field.getClassDefinition();

            Expression e = this;
            if (env.opt() && field.isInlineable(env, clazz.isFinal()) &&

                // Don't inline if a qualified non-static method: the call
                // itself might throw NullPointerException as a side effect
                ((right == null) || (right.op==THIS) || field.isStatic()) &&

                // We only allow the inlining if the current class can access
                // the field, the field's class, and right's declared type.
                ctxClass.permitInlinedAccess(env,
                              field.getClassDeclaration()) &&
                ctxClass.permitInlinedAccess(env, field) &&
                (right==null || ctxClass.permitInlinedAccess(env,
                              env.getClassDeclaration(right.type)))  &&

                ((id == null) || !id.equals(idInit)) &&
                (!ctx.field.isInitializer()) && ctx.field.isMethod() &&
                (ctx.getInlineMemberContext(field) == null)) {
                Statement s = (Statement)field.getValue(env);
                if ((s == null) ||
                    (s.costInline(MAXINLINECOST, env, ctx) < MAXINLINECOST))  {
                    e = inlineMethod(env, ctx, s, false);
                }
            }
            return e;

        } catch (ClassNotFound e) {
            throw new CompilerError(e);
        }
    }

    public Expression inlineValue(Environment env, Context ctx) {
        if (implementation != null)
            return implementation.inlineValue(env, ctx);
        try {
            if (right != null) {
                right = field.isStatic() ? right.inline(env, ctx) : right.inlineValue(env, ctx);
            }
            if (field.getName().equals(idInit)) {
                ClassDefinition refc = field.getClassDefinition();
                UplevelReference r = refc.getReferencesFrozen();
                if (r != null) {
                    r.willCodeArguments(env, ctx);
                }
            }
            for (int i = 0 ; i < args.length ; i++) {
                args[i] = args[i].inlineValue(env, ctx);
            }

            // ctxClass is the current class trying to inline this method
            ClassDefinition ctxClass = ctx.field.getClassDefinition();

            if (env.opt() && field.isInlineable(env, clazz.isFinal()) &&

                // Don't inline if a qualified non-static method: the call
                // itself might throw NullPointerException as a side effect
                ((right == null) || (right.op==THIS) || field.isStatic()) &&

                // We only allow the inlining if the current class can access
                // the field, the field's class, and right's declared type.
                ctxClass.permitInlinedAccess(env,
                              field.getClassDeclaration()) &&
                ctxClass.permitInlinedAccess(env, field) &&
                (right==null || ctxClass.permitInlinedAccess(env,
                              env.getClassDeclaration(right.type)))  &&

                (!ctx.field.isInitializer()) && ctx.field.isMethod() &&
                (ctx.getInlineMemberContext(field) == null)) {
                Statement s = (Statement)field.getValue(env);
                if ((s == null) ||
                    (s.costInline(MAXINLINECOST, env, ctx) < MAXINLINECOST))  {
                    return inlineMethod(env, ctx, s, true);
                }
            }
            return this;
        } catch (ClassNotFound e) {
            throw new CompilerError(e);
        }
    }

    public Expression copyInline(Context ctx) {
        if (implementation != null)
            return implementation.copyInline(ctx);
        return super.copyInline(ctx);
    }

    public int costInline(int thresh, Environment env, Context ctx) {
        if (implementation != null)
            return implementation.costInline(thresh, env, ctx);

        // for now, don't allow calls to super() to be inlined.  We may fix
        // this later
        if ((right != null) && (right.op == SUPER)) {
            return thresh;
        }
        return super.costInline(thresh, env, ctx);
    }

    /*
     * Grab all instance initializer code from the class definition,
     * and return as one bolus.  Note that we are assuming the
     * the relevant fields have already been checked.
     * (See the pre-pass in SourceClass.checkMembers which ensures this.)
     */
    private Expression makeVarInits(Environment env, Context ctx) {
        // insert instance initializers
        ClassDefinition clazz = ctx.field.getClassDefinition();
        Expression e = null;
        for (MemberDefinition f = clazz.getFirstMember() ; f != null ; f = f.getNextMember()) {
            if ((f.isVariable() || f.isInitializer()) && !f.isStatic()) {
                try {
                    f.check(env);
                } catch (ClassNotFound ee) {
                    env.error(f.getWhere(), "class.not.found", ee.name,
                              f.getClassDefinition());
                }
                Expression val = null;
                if (f.isUplevelValue()) {
                    if (f != clazz.findOuterMember()) {
                        // it's too early to accumulate these
                        continue;
                    }
                    IdentifierExpression arg =
                        new IdentifierExpression(where, f.getName());
                    if (!arg.bind(env, ctx)) {
                        throw new CompilerError("bind "+arg.id);
                    }
                    val = arg;
                } else if (f.isInitializer()) {
                    Statement s = (Statement)f.getValue();
                    val = new InlineMethodExpression(where, Type.tVoid, f, s);
                } else {
                    val = (Expression)f.getValue();
                }
                // append all initializers to "e":
                // This section used to check for variables which were
                // initialized to their default values and elide such
                // initialization.  This is specifically disallowed by
                // JLS 12.5 numeral 4, which requires a textual ordering
                // on the execution of initializers.
                if ((val != null)) { //  && !val.equals(0)) {
                    long p = f.getWhere();
                    val = val.copyInline(ctx);
                    Expression init = val;
                    if (f.isVariable()) {
                        Expression v = new ThisExpression(p, ctx);
                    v = new FieldExpression(p, v, f);
                    init = new AssignExpression(p, v, val);
                    }
                    e = (e == null) ? init : new CommaExpression(p, e, init);
                }
            }
        }
        return e;
    }

    /**
     * Code
     */
    public void codeValue(Environment env, Context ctx, Assembler asm) {
        if (implementation != null)
            throw new CompilerError("codeValue");
        int i = 0;              // argument index
        if (field.isStatic()) {
            if (right != null) {
                right.code(env, ctx, asm);
            }
        } else if (right == null) {
            asm.add(where, opc_aload, 0);
        } else if (right.op == SUPER) {
            // 'super.<method>(...)', 'super(...)', or '<expr>.super(...)'
            /*****
            isSuper = true;
            *****/
            right.codeValue(env, ctx, asm);
            if (idInit.equals(id)) {
                // 'super(...)' or '<expr>.super(...)' only
                ClassDefinition refc = field.getClassDefinition();
                UplevelReference r = refc.getReferencesFrozen();
                if (r != null) {
                    // When calling a constructor for a class with
                    // embedded uplevel references, add extra arguments.
                    if (r.isClientOuterField()) {
                        // the extra arguments are inserted after this one
                        args[i++].codeValue(env, ctx, asm);
                    }
                    r.codeArguments(env, ctx, asm, where, field);
                }
            }
        } else {
            right.codeValue(env, ctx, asm);
            /*****
            if (right.op == FIELD &&
                ((FieldExpression)right).id == idSuper) {
                // '<class>.super.<method>(...)'
                isSuper = true;
            }
            *****/
        }

        for ( ; i < args.length ; i++) {
            args[i].codeValue(env, ctx, asm);
        }

        if (field.isStatic()) {
            asm.add(where, opc_invokestatic, field);
        } else if (field.isConstructor() || field.isPrivate() || isSuper) {
            asm.add(where, opc_invokespecial, field);
        } else if (field.getClassDefinition().isInterface()) {
            asm.add(where, opc_invokeinterface, field);
        } else {
            asm.add(where, opc_invokevirtual, field);
        }

        if (right != null && right.op == SUPER && idInit.equals(id)) {
            // 'super(...)' or '<expr>.super(...)'
            ClassDefinition refc = ctx.field.getClassDefinition();
            UplevelReference r = refc.getReferencesFrozen();
            if (r != null) {
                // After calling a superclass constructor in a class with
                // embedded uplevel references, initialize uplevel fields.
                r.codeInitialization(env, ctx, asm, where, field);
            }
        }
    }

    /**
     * Check if the first thing is a constructor invocation
     */
    public Expression firstConstructor() {
        return id.equals(idInit) ? this : null;
    }

    /**
     * Print
     */
    public void print(PrintStream out) {
        out.print("(" + opNames[op]);
        if (right != null) {
            out.print(" ");
            right.print(out);
        }
        out.print(" " + ((id == null) ? idInit : id));
        for (int i = 0 ; i < args.length ; i++) {
            out.print(" ");
            if (args[i] != null) {
                args[i].print(out);
            } else {
                out.print("<null>");
            }
        }
        out.print(")");
        if (implementation != null) {
            out.print("/IMPL=");
            implementation.print(out);
        }
    }
}