271 lines · 8.9 KB · Java
RawDownload
/* * 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 * or visit www.oracle.com if you need additional information or have any * 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. */publicclass ArrayAccessExpression extends UnaryExpression {     /**     * The index expression for the array access.  Note that     * ArrayAccessExpression also `moonlights' as a structure for     * storing array types (like Object[]) which are used as part     * of cast expressions.  For properly formed array types, the     * value of index is null.  We need to be on the lookout for     * null indices in true array accesses, and non-null indices     * in array types.  We also need to make sure general purpose     * methods (like copyInline(), which is called for both) are     * prepared to handle either null or non-null indices.     */    Expression index;     /**     * constructor     */    public ArrayAccessExpression(long where, Expression right, Expression index) {        super(ARRAYACCESS, where, Type.tError, right);        this.index = index;    }     /**     * Check expression type     */    public Vset checkValue(Environment env, Context ctx, Vset vset, Hashtable exp) {        vset = right.checkValue(env, ctx, vset, exp);        if (index == null) {            env.error(where, "array.index.required");            return vset;        }        vset = index.checkValue(env, ctx, vset, exp);        index = convert(env, ctx, Type.tInt, index);         if (!right.type.isType(TC_ARRAY)) {            if (!right.type.isType(TC_ERROR)) {                env.error(where, "not.array", right.type);            }            return vset;        }         type = right.type.getElementType();        return vset;    }     public Vset checkAmbigName(Environment env, Context ctx,                               Vset vset, Hashtable exp,                               UnaryExpression loc) {        if (index == null) {            vset = right.checkAmbigName(env, ctx, vset, exp, this);            if (right.type == Type.tPackage) {                FieldExpression.reportFailedPackagePrefix(env, right);                return vset;            }             // Nope.  Is this field expression a type?            if (right instanceof TypeExpression) {                Type atype = Type.tArray(right.type);                loc.right = new TypeExpression(where, atype);                return vset;            }             env.error(where, "array.index.required");            return vset;        }        return super.checkAmbigName(env, ctx, vset, exp, loc);    }     /*     * Check the array if it appears on the LHS of an assignment     */    public Vset checkLHS(Environment env, Context ctx,                         Vset vset, Hashtable exp) {        return checkValue(env, ctx, vset, exp);    }     /*     * Check the array if it appears on the LHS of an op= expression     */    public Vset checkAssignOp(Environment env, Context ctx,                              Vset vset, Hashtable exp, Expression outside) {        return checkValue(env, ctx, vset, exp);    }     /**     * An array access expression never requires the use of an access method to perform     * an assignment to an array element, though an access method may be required to     * fetch the array object itself.     */    public FieldUpdater getAssigner(Environment env, Context ctx) {        return null;    }     /**     * An array access expression never requires a field updater.     */    public FieldUpdater getUpdater(Environment env, Context ctx) {        return null;    }     /**     * Convert to a type     */    Type toType(Environment env, Context ctx) {        return toType(env, right.toType(env, ctx));    }    Type toType(Environment env, Type t) {        if (index != null) {            env.error(index.where, "array.dim.in.type");        }        return Type.tArray(t);    }     /**     * Inline     */    public Expression inline(Environment env, Context ctx) {        // It isn't possible to simply replace an array access        // with a CommaExpression as happens with many binary        // operators, because array accesses may have side effects        // such as NullPointerException or IndexOutOfBoundsException.        right = right.inlineValue(env, ctx);        index = index.inlineValue(env, ctx);        return this;    }    public Expression inlineValue(Environment env, Context ctx) {        // inlineValue() should not end up being called when the index is        // null.  If it is null, we let this method fail with a        // NullPointerException.         right = right.inlineValue(env, ctx);        index = index.inlineValue(env, ctx);        return this;    }    public Expression inlineLHS(Environment env, Context ctx) {        return inlineValue(env, ctx);    }     /**     * Create a copy of the expression for method inlining     */    public Expression copyInline(Context ctx) {        ArrayAccessExpression e = (ArrayAccessExpression)clone();        e.right = right.copyInline(ctx);        if (index == null) {            // The index can be null when this node is being used to            // represent a type (e.g. Object[]) used in a cast expression.            // We need to copy such structures without complaint.            e.index = null;        } else {            e.index = index.copyInline(ctx);        }        return e;    }     /**     * The cost of inlining this expression     */    public int costInline(int thresh, Environment env, Context ctx) {        // costInline() should not end up being called when the index is        // null.  If it is null, we let this method fail with a        // NullPointerException.         return 1 + right.costInline(thresh, env, ctx)            + index.costInline(thresh, env, ctx);    }     /**     * Code     */    int codeLValue(Environment env, Context ctx, Assembler asm) {        // codeLValue() should not end up being called when the index is        // null.  If it is null, we let this method fail with a        // NullPointerException.         right.codeValue(env, ctx, asm);        index.codeValue(env, ctx, asm);        return 2;    }    void codeLoad(Environment env, Context ctx, Assembler asm) {        switch (type.getTypeCode()) {          case TC_BOOLEAN:          case TC_BYTE:            asm.add(where, opc_baload);            break;          case TC_CHAR:            asm.add(where, opc_caload);            break;          case TC_SHORT:            asm.add(where, opc_saload);            break;          default:            asm.add(where, opc_iaload + type.getTypeCodeOffset());        }    }    void codeStore(Environment env, Context ctx, Assembler asm) {        switch (type.getTypeCode()) {          case TC_BOOLEAN:          case TC_BYTE:            asm.add(where, opc_bastore);            break;          case TC_CHAR:            asm.add(where, opc_castore);            break;          case TC_SHORT:            asm.add(where, opc_sastore);            break;          default:            asm.add(where, opc_iastore + type.getTypeCodeOffset());        }    }    public void codeValue(Environment env, Context ctx, Assembler asm) {        codeLValue(env, ctx, asm);        codeLoad(env, ctx, asm);    }      /**     * Print     */    public void print(PrintStream out) {        out.print("(" + opNames[op] + " ");        right.print(out);        out.print(" ");        if (index != null) {            index.print(out);        } else {        out.print("<empty>");        }        out.print(")");    }}