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	/*
	* 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.
	*/
	public abstract
	class AssignOpExpression extends BinaryAssignExpression {
	protected Type itype; // Type of intermediate result, before assigning
	final int NOINC = Integer.MAX_VALUE;

	protected FieldUpdater updater = null; // Used also in 'AssignAddExpression'.

	/**
	* Constructor
	*/
	public AssignOpExpression(int op, long where, Expression left, Expression right) {
	super(op, where, left, right);
	}

	/**
	* Select the type
	*
	*/

	final void selectType(Environment env, Context ctx, int tm) {
	Type rtype = null; // special conversion type for RHS
	switch(op) {
	case ASGADD:
	if (left.type == Type.tString) {
	if (right.type == Type.tVoid) {
	// The type of the right hand side can be
	// anything except void. Fix for 4119864.
	env.error(where, "incompatible.type",
	opNames[op], Type.tVoid, Type.tString);
	type = Type.tError;
	} else {
	type = itype = Type.tString;
	}
	return;
	}
	/* Fall through */
	case ASGDIV: case ASGMUL: case ASGSUB: case ASGREM:
	if ((tm & TM_DOUBLE) != 0) {
	itype = Type.tDouble;
	} else if ((tm & TM_FLOAT) != 0) {
	itype = Type.tFloat;
	} else if ((tm & TM_LONG) != 0) {
	itype = Type.tLong;
	} else {
	itype = Type.tInt;
	}
	break;

	case ASGBITAND: case ASGBITOR: case ASGBITXOR:
	if ((tm & TM_BOOLEAN) != 0) {
	itype = Type.tBoolean;
	} else if ((tm & TM_LONG) != 0) {
	itype = Type.tLong;
	} else {
	itype = Type.tInt;
	}
	break;

	case ASGLSHIFT: case ASGRSHIFT: case ASGURSHIFT:
	rtype = Type.tInt;

	// Fix for bug 4134459.
	// We allow any integral type (even long) to
	// be the right hand side of a shift operation.
	if (right.type.inMask(TM_INTEGER)) {
	right = new ConvertExpression(where, Type.tInt, right);
	}
	// The intermediate type of the expression is the
	// type of the left hand side after undergoing
	// unary (not binary) type promotion. We ignore
	// tm -- it contains information about both left
	// and right hand sides -- and we compute the
	// type only from the type of the lhs.
	if (left.type == Type.tLong) {
	itype = Type.tLong;
	} else {
	itype = Type.tInt;
	}

	break;

	default:
	throw new CompilerError("Bad assignOp type: " + op);
	}
	if (rtype == null) {
	rtype = itype;
	}
	right = convert(env, ctx, rtype, right);
	// The result is always the type of the left operand.

	type = left.type;
	}


	/**
	* Get the increment, return NOINC if an increment is not possible
	*/
	int getIncrement() {
	if ((left.op == IDENT) && type.isType(TC_INT) && (right.op == INTVAL))
	if ((op == ASGADD) \|\| (op == ASGSUB))
	if (((IdentifierExpression)left).field.isLocal()) {
	int val = ((IntExpression)right).value;
	if (op == ASGSUB)
	val = -val;
	if (val == (short)val)
	return val;
	}
	return NOINC;
	}


	/**
	* Check an assignment expression
	*/
	public Vset checkValue(Environment env, Context ctx, Vset vset, Hashtable exp) {
	vset = left.checkAssignOp(env, ctx, vset, exp, this);
	vset = right.checkValue(env, ctx, vset, exp);
	int tm = left.type.getTypeMask() \| right.type.getTypeMask();
	if ((tm & TM_ERROR) != 0) {
	return vset;
	}
	selectType(env, ctx, tm);
	if (!type.isType(TC_ERROR)) {
	convert(env, ctx, itype, left);
	}
	updater = left.getUpdater(env, ctx); // Must be called after 'checkAssignOp'.
	return vset;
	}

	/**
	* Inline
	*/
	public Expression inlineValue(Environment env, Context ctx) {
	// Why not inlineLHS? But that does not work.
	left = left.inlineValue(env, ctx);
	right = right.inlineValue(env, ctx);
	if (updater != null) {
	updater = updater.inline(env, ctx);
	}
	return this;
	}

	/**
	* Create a copy of the expression for method inlining
	*/
	public Expression copyInline(Context ctx) {
	AssignOpExpression e = (AssignOpExpression)clone();
	e.left = left.copyInline(ctx);
	e.right = right.copyInline(ctx);
	if (updater != null) {
	e.updater = updater.copyInline(ctx);
	}
	return e;
	}

	/**
	* The cost of inlining this statement
	*/
	public int costInline(int thresh, Environment env, Context ctx) {
	/----------
	return (getIncrement() != NOINC)
	? 2
	: (3 + super.costInline(thresh, env, ctx));
	----------/
	if (updater == null) {
	return (getIncrement() != NOINC)
	// Increment variable in place. Count 3 bytes for 'iinc'.
	? 3
	// Cost of rhs expression + cost of lhs expression + cost
	// of load/op/store instructions. E.g.: iload = 1 or 2,
	// istore = 1 or 2, iadd = 1. Cost could be higher if
	// getfield/putfield or conversions needed, lower if rhs is
	// a small constant. Costs are highly approximate.
	: right.costInline(thresh, env, ctx) +
	left.costInline(thresh, env, ctx) + 4;
	} else {
	// Cost of rhs expression + (2 * cost of access method call) +
	// cost of operator. Does not account for cost of conversions,
	// or duplications in value-needed context.
	return right.costInline(thresh, env, ctx) +
	updater.costInline(thresh, env, ctx, true) + 1;
	}
	}

	/**
	* Code
	*/
	void code(Environment env, Context ctx, Assembler asm, boolean valNeeded) {

	// Handle cases in which a '+=' or '-=' operator can be optimized using
	// the 'iinc' instruction. See also 'IncDecExpression.codeIncDec'.
	// The 'iinc' instruction cannot be used if an access method call is required.
	int val = getIncrement();
	if (val != NOINC && updater == null) {
	int v = ((LocalMember)((IdentifierExpression)left).field).number;
	int[] operands = { v, val };
	asm.add(where, opc_iinc, operands);
	if (valNeeded) {
	left.codeValue(env, ctx, asm);
	}
	return;
	}

	if (updater == null) {
	// Field is directly accessible.
	int depth = left.codeLValue(env, ctx, asm);
	codeDup(env, ctx, asm, depth, 0);
	left.codeLoad(env, ctx, asm);
	codeConversion(env, ctx, asm, left.type, itype);
	right.codeValue(env, ctx, asm);
	codeOperation(env, ctx, asm);
	codeConversion(env, ctx, asm, itype, type);
	if (valNeeded) {
	codeDup(env, ctx, asm, type.stackSize(), depth);
	}
	left.codeStore(env, ctx, asm);
	} else {
	// Must use access methods.
	updater.startUpdate(env, ctx, asm, false);
	codeConversion(env, ctx, asm, left.type, itype);
	right.codeValue(env, ctx, asm);
	codeOperation(env, ctx, asm);
	codeConversion(env, ctx, asm, itype, type);
	updater.finishUpdate(env, ctx, asm, valNeeded);
	}
	}

	public void codeValue(Environment env, Context ctx, Assembler asm) {
	code(env, ctx, asm, true);
	}
	public void code(Environment env, Context ctx, Assembler asm) {
	code(env, ctx, asm, false);
	}

	/**
	* Print
	*/
	public void print(PrintStream out) {
	out.print("(" + opNames[op] + " ");
	left.print(out);
	out.print(" ");
	right.print(out);
	out.print(")");
	}
	}

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