UnaryExpression.java

/*******************************************************************************
 * Copyright (c) 2000, 2020 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     Stephan Herrmann - Contribution for
 *								bug 383368 - [compiler][null] syntactic null analysis for field references
 *								bug 403086 - [compiler][null] include the effect of 'assert' in syntactic null analysis for fields
 *******************************************************************************/
package org.eclipse.jdt.internal.compiler.ast;

import org.eclipse.jdt.internal.compiler.ASTVisitor;
import org.eclipse.jdt.internal.compiler.impl.*;
import org.eclipse.jdt.internal.compiler.classfmt.ClassFileConstants;
import org.eclipse.jdt.internal.compiler.codegen.*;
import org.eclipse.jdt.internal.compiler.flow.*;
import org.eclipse.jdt.internal.compiler.lookup.*;

public class UnaryExpression extends OperatorExpression {

	public Expression expression;
	public Constant optimizedBooleanConstant;

	public UnaryExpression(Expression expression, int operator) {
		this.expression = expression;
		this.bits |= operator << OperatorSHIFT; // encode operator
	}

	@Override
	public FlowInfo analyseCode(
			BlockScope currentScope,
			FlowContext flowContext,
			FlowInfo flowInfo) {
		if (((this.bits & OperatorMASK) >> OperatorSHIFT) == NOT) {
			flowContext.tagBits ^= FlowContext.INSIDE_NEGATION;
			flowInfo = this.expression.
				analyseCode(currentScope, flowContext, flowInfo).
				asNegatedCondition();
			flowContext.tagBits ^= FlowContext.INSIDE_NEGATION;
		} else {
			flowInfo = this.expression.
				analyseCode(currentScope, flowContext, flowInfo);
		}
		this.expression.checkNPE(currentScope, flowContext, flowInfo);
		return flowInfo;
	}

	@Override
	protected void updateFlowOnBooleanResult(FlowInfo flowInfo, boolean result) {
		if (((this.bits & OperatorMASK) >> OperatorSHIFT) == NOT)
			this.expression.updateFlowOnBooleanResult(flowInfo, !result);
	}

	@Override
	public Constant optimizedBooleanConstant() {

		return this.optimizedBooleanConstant == null
				? this.constant
				: this.optimizedBooleanConstant;
	}

	/**
	 * Code generation for an unary operation
	 *
	 * @param currentScope org.eclipse.jdt.internal.compiler.lookup.BlockScope
	 * @param codeStream org.eclipse.jdt.internal.compiler.codegen.CodeStream
	 * @param valueRequired boolean
	 */
	@Override
	public void generateCode(
		BlockScope currentScope,
		CodeStream codeStream,
		boolean valueRequired) {

		int pc = codeStream.position;
		BranchLabel falseLabel, endifLabel;
		if (this.constant != Constant.NotAConstant) {
			// inlined value
			if (valueRequired) {
				codeStream.generateConstant(this.constant, this.implicitConversion);
			}
			codeStream.recordPositionsFrom(pc, this.sourceStart);
			return;
		}
		switch ((this.bits & OperatorMASK) >> OperatorSHIFT) {
			case NOT :
				switch ((this.expression.implicitConversion & IMPLICIT_CONVERSION_MASK) >> 4) /* runtime type */ {
					case T_boolean :
						// ! <boolean>
						// Generate code for the condition
						this.expression.generateOptimizedBoolean(
							currentScope,
							codeStream,
							null,
							(falseLabel = new BranchLabel(codeStream)),
							valueRequired);
						if (valueRequired) {
							codeStream.iconst_0();
							if (falseLabel.forwardReferenceCount() > 0) {
								codeStream.goto_(endifLabel = new BranchLabel(codeStream));
								codeStream.decrStackSize(1);
								falseLabel.place();
								codeStream.iconst_1();
								endifLabel.place();
							}
						} else { // 6596: if (!(a && b)){} - must still place falseLabel
							falseLabel.place();
						}
						break;
				}
				break;
			case TWIDDLE :
				switch ((this.expression.implicitConversion & IMPLICIT_CONVERSION_MASK) >> 4 /* runtime */) {
					case T_int :
						// ~int
						this.expression.generateCode(currentScope, codeStream, valueRequired);
						if (valueRequired) {
							codeStream.iconst_m1();
							codeStream.ixor();
						}
						break;
					case T_long :
						this.expression.generateCode(currentScope, codeStream, valueRequired);
						if (valueRequired) {
							codeStream.ldc2_w(-1L);
							codeStream.lxor();
						}
				}
				break;
			case MINUS :
				// - <num>
				if (this.constant != Constant.NotAConstant) {
					if (valueRequired) {
						switch ((this.expression.implicitConversion & IMPLICIT_CONVERSION_MASK) >> 4){ /* runtime */
							case T_int :
								codeStream.generateInlinedValue(this.constant.intValue() * -1);
								break;
							case T_float :
								codeStream.generateInlinedValue(this.constant.floatValue() * -1.0f);
								break;
							case T_long :
								codeStream.generateInlinedValue(this.constant.longValue() * -1L);
								break;
							case T_double :
								codeStream.generateInlinedValue(this.constant.doubleValue() * -1.0);
						}
					}
				} else {
					this.expression.generateCode(currentScope, codeStream, valueRequired);
					if (valueRequired) {
						switch ((this.expression.implicitConversion & IMPLICIT_CONVERSION_MASK) >> 4){ /* runtime type */
							case T_int :
								codeStream.ineg();
								break;
							case T_float :
								codeStream.fneg();
								break;
							case T_long :
								codeStream.lneg();
								break;
							case T_double :
								codeStream.dneg();
						}
					}
				}
				break;
			case PLUS :
				this.expression.generateCode(currentScope, codeStream, valueRequired);
		}
		if (valueRequired) {
			codeStream.generateImplicitConversion(this.implicitConversion);
		}
		codeStream.recordPositionsFrom(pc, this.sourceStart);
	}

	/**
	 * Boolean operator code generation
	 *	Optimized operations are: &&, ||, <, <=, >, >=, &, |, ^
	 */
	@Override
	public void generateOptimizedBoolean(
		BlockScope currentScope,
		CodeStream codeStream,
		BranchLabel trueLabel,
		BranchLabel falseLabel,
		boolean valueRequired) {

		if ((this.constant != Constant.NotAConstant) && (this.constant.typeID() == T_boolean)) {
			super.generateOptimizedBoolean(
				currentScope,
				codeStream,
				trueLabel,
				falseLabel,
				valueRequired);
			return;
		}
		if (((this.bits & OperatorMASK) >> OperatorSHIFT) == NOT) {
			this.expression.generateOptimizedBoolean(
				currentScope,
				codeStream,
				falseLabel,
				trueLabel,
				valueRequired);
		} else {
			super.generateOptimizedBoolean(
				currentScope,
				codeStream,
				trueLabel,
				falseLabel,
				valueRequired);
		}
	}

	@Override
	public StringBuffer printExpressionNoParenthesis(int indent, StringBuffer output) {

		output.append(operatorToString()).append(' ');
		return this.expression.printExpression(0, output);
	}

	@Override
	public TypeBinding resolveType(BlockScope scope) {
		boolean expressionIsCast;
		if ((expressionIsCast = this.expression instanceof CastExpression) == true) this.expression.bits |= DisableUnnecessaryCastCheck; // will check later on
		TypeBinding expressionType = this.expression.resolveType(scope);
		if (expressionType == null) {
			this.constant = Constant.NotAConstant;
			return null;
		}
		int expressionTypeID = expressionType.id;
		// autoboxing support
		boolean use15specifics = scope.compilerOptions().sourceLevel >= ClassFileConstants.JDK1_5;
		if (use15specifics) {
			if (!expressionType.isBaseType()) {
				expressionTypeID = scope.environment().computeBoxingType(expressionType).id;
			}
		}
		if (expressionTypeID > 15) {
			this.constant = Constant.NotAConstant;
			scope.problemReporter().invalidOperator(this, expressionType);
			return null;
		}

		int tableId;
		switch ((this.bits & OperatorMASK) >> OperatorSHIFT) {
			case NOT :
				tableId = AND_AND;
				break;
			case TWIDDLE :
				tableId = LEFT_SHIFT;
				break;
			default :
				tableId = MINUS;
		} //+ and - cases

		// the code is an int
		// (cast)  left   Op (cast)  rigth --> result
		//  0000   0000       0000   0000      0000
		//  <<16   <<12       <<8    <<4       <<0
		int operatorSignature = OperatorSignatures[tableId][(expressionTypeID << 4) + expressionTypeID];
		this.expression.computeConversion(scope, TypeBinding.wellKnownType(scope, (operatorSignature >>> 16) & 0x0000F), expressionType);
		this.bits |= operatorSignature & 0xF;
		switch (operatorSignature & 0xF) { // only switch on possible result type.....
			case T_boolean :
				this.resolvedType = TypeBinding.BOOLEAN;
				break;
			case T_byte :
				this.resolvedType = TypeBinding.BYTE;
				break;
			case T_char :
				this.resolvedType = TypeBinding.CHAR;
				break;
			case T_double :
				this.resolvedType = TypeBinding.DOUBLE;
				break;
			case T_float :
				this.resolvedType = TypeBinding.FLOAT;
				break;
			case T_int :
				this.resolvedType = TypeBinding.INT;
				break;
			case T_long :
				this.resolvedType = TypeBinding.LONG;
				break;
			default : //error........
				this.constant = Constant.NotAConstant;
				if (expressionTypeID != T_undefined)
					scope.problemReporter().invalidOperator(this, expressionType);
				return null;
		}
		// compute the constant when valid
		if (this.expression.constant != Constant.NotAConstant) {
			this.constant =
				Constant.computeConstantOperation(
					this.expression.constant,
					expressionTypeID,
					(this.bits & OperatorMASK) >> OperatorSHIFT);
		} else {
			this.constant = Constant.NotAConstant;
			if (((this.bits & OperatorMASK) >> OperatorSHIFT) == NOT) {
				Constant cst = this.expression.optimizedBooleanConstant();
				if (cst != Constant.NotAConstant)
					this.optimizedBooleanConstant = BooleanConstant.fromValue(!cst.booleanValue());
			}
		}
		if (expressionIsCast) {
		// check need for operand cast
			CastExpression.checkNeedForArgumentCast(scope, tableId, operatorSignature, this.expression, expressionTypeID);
		}
		return this.resolvedType;
	}
	@Override
	public boolean containsPatternVariable() {
		return this.expression.containsPatternVariable();
	}

	@Override
	public void traverse(
    		ASTVisitor visitor,
    		BlockScope blockScope) {

		if (visitor.visit(this, blockScope)) {
			this.expression.traverse(visitor, blockScope);
		}
		visitor.endVisit(this, blockScope);
	}
}