net.sourceforge.phpeclipse/src/net/sourceforge/phpdt/internal/compiler/ast/ConditionalExpression.java

   1 /*******************************************************************************
   2  * Copyright (c) 2000, 2003 IBM Corporation and others.
   3  * All rights reserved. This program and the accompanying materials
   4  * are made available under the terms of the Common Public License v1.0
   5  * which accompanies this distribution, and is available at
   6  * http://www.eclipse.org/legal/cpl-v10.html
   7  *
   8  * Contributors:
   9  *     IBM Corporation - initial API and implementation
  10  *******************************************************************************/
  11 package net.sourceforge.phpdt.internal.compiler.ast;
  12
  13 import net.sourceforge.phpdt.internal.compiler.ASTVisitor;
  14 import net.sourceforge.phpdt.internal.compiler.flow.FlowContext;
  15 import net.sourceforge.phpdt.internal.compiler.flow.FlowInfo;
  16 import net.sourceforge.phpdt.internal.compiler.flow.UnconditionalFlowInfo;
  17 import net.sourceforge.phpdt.internal.compiler.impl.Constant;
  18 import net.sourceforge.phpdt.internal.compiler.lookup.BlockScope;
  19
  20 public class ConditionalExpression extends OperatorExpression {
  21
  22         public Expression condition, valueIfTrue, valueIfFalse;
  23
  24         public Constant optimizedBooleanConstant;
  25
  26         public Constant optimizedIfTrueConstant;
  27
  28         public Constant optimizedIfFalseConstant;
  29
  30         //private int returnTypeSlotSize = 1;
  31
  32         // for local variables table attributes
  33         int trueInitStateIndex = -1;
  34
  35         int falseInitStateIndex = -1;
  36
  37         int mergedInitStateIndex = -1;
  38
  39         public ConditionalExpression(Expression condition, Expression valueIfTrue,
  40                         Expression valueIfFalse) {
  41                 this.condition = condition;
  42                 this.valueIfTrue = valueIfTrue;
  43                 this.valueIfFalse = valueIfFalse;
  44                 sourceStart = condition.sourceStart;
  45                 sourceEnd = valueIfFalse.sourceEnd;
  46         }
  47
  48         public FlowInfo analyseCode(BlockScope currentScope,
  49                         FlowContext flowContext, FlowInfo flowInfo) {
  50
  51                 Constant cst = this.condition.optimizedBooleanConstant();
  52                 boolean isConditionOptimizedTrue = cst != NotAConstant
  53                                 && cst.booleanValue() == true;
  54                 boolean isConditionOptimizedFalse = cst != NotAConstant
  55                                 && cst.booleanValue() == false;
  56
  57                 int mode = flowInfo.reachMode();
  58                 flowInfo = condition.analyseCode(currentScope, flowContext, flowInfo,
  59                                 cst == NotAConstant);
  60
  61                 // process the if-true part
  62                 FlowInfo trueFlowInfo = flowInfo.initsWhenTrue().copy();
  63                 if (isConditionOptimizedFalse) {
  64                         trueFlowInfo.setReachMode(FlowInfo.UNREACHABLE);
  65                 }
  66                 trueInitStateIndex = currentScope.methodScope()
  67                                 .recordInitializationStates(trueFlowInfo);
  68                 trueFlowInfo = valueIfTrue.analyseCode(currentScope, flowContext,
  69                                 trueFlowInfo);
  70
  71                 // process the if-false part
  72                 FlowInfo falseFlowInfo = flowInfo.initsWhenFalse().copy();
  73                 if (isConditionOptimizedTrue) {
  74                         falseFlowInfo.setReachMode(FlowInfo.UNREACHABLE);
  75                 }
  76                 falseInitStateIndex = currentScope.methodScope()
  77                                 .recordInitializationStates(falseFlowInfo);
  78                 falseFlowInfo = valueIfFalse.analyseCode(currentScope, flowContext,
  79                                 falseFlowInfo);
  80
  81                 // merge if-true & if-false initializations
  82                 FlowInfo mergedInfo;
  83                 if (isConditionOptimizedTrue) {
  84                         mergedInfo = trueFlowInfo
  85                                         .addPotentialInitializationsFrom(falseFlowInfo);
  86                 } else if (isConditionOptimizedFalse) {
  87                         mergedInfo = falseFlowInfo
  88                                         .addPotentialInitializationsFrom(trueFlowInfo);
  89                 } else {
  90                         // merge using a conditional info - 1GK2BLM
  91                         // if ((t && (v = t)) ? t : t && (v = f)) r = v; -- ok
  92                         cst = this.optimizedIfTrueConstant;
  93                         boolean isValueIfTrueOptimizedTrue = cst != null
  94                                         && cst != NotAConstant && cst.booleanValue() == true;
  95                         boolean isValueIfTrueOptimizedFalse = cst != null
  96                                         && cst != NotAConstant && cst.booleanValue() == false;
  97
  98                         cst = this.optimizedIfFalseConstant;
  99                         boolean isValueIfFalseOptimizedTrue = cst != null
 100                                         && cst != NotAConstant && cst.booleanValue() == true;
 101                         boolean isValueIfFalseOptimizedFalse = cst != null
 102                                         && cst != NotAConstant && cst.booleanValue() == false;
 103
 104                         UnconditionalFlowInfo trueInfoWhenTrue = trueFlowInfo
 105                                         .initsWhenTrue().copy().unconditionalInits();
 106                         if (isValueIfTrueOptimizedFalse)
 107                                 trueInfoWhenTrue.setReachMode(FlowInfo.UNREACHABLE);
 108
 109                         UnconditionalFlowInfo falseInfoWhenTrue = falseFlowInfo
 110                                         .initsWhenTrue().copy().unconditionalInits();
 111                         if (isValueIfFalseOptimizedFalse)
 112                                 falseInfoWhenTrue.setReachMode(FlowInfo.UNREACHABLE);
 113
 114                         UnconditionalFlowInfo trueInfoWhenFalse = trueFlowInfo
 115                                         .initsWhenFalse().copy().unconditionalInits();
 116                         if (isValueIfTrueOptimizedTrue)
 117                                 trueInfoWhenFalse.setReachMode(FlowInfo.UNREACHABLE);
 118
 119                         UnconditionalFlowInfo falseInfoWhenFalse = falseFlowInfo
 120                                         .initsWhenFalse().copy().unconditionalInits();
 121                         if (isValueIfFalseOptimizedTrue)
 122                                 falseInfoWhenFalse.setReachMode(FlowInfo.UNREACHABLE);
 123
 124                         mergedInfo = FlowInfo.conditional(trueInfoWhenTrue
 125                                         .mergedWith(falseInfoWhenTrue), trueInfoWhenFalse
 126                                         .mergedWith(falseInfoWhenFalse));
 127                 }
 128                 mergedInitStateIndex = currentScope.methodScope()
 129                                 .recordInitializationStates(mergedInfo);
 130                 mergedInfo.setReachMode(mode);
 131                 return mergedInfo;
 132         }
 133
 134         /**
 135          * Code generation for the conditional operator ?:
 136          *
 137          * @param currentScope
 138          *            net.sourceforge.phpdt.internal.compiler.lookup.BlockScope
 139          * @param codeStream
 140          *            net.sourceforge.phpdt.internal.compiler.codegen.CodeStream
 141          * @param valueRequired
 142          *            boolean
 143          */
 144         // public void generateCode(
 145         // BlockScope currentScope,
 146         // CodeStream codeStream,
 147         // boolean valueRequired) {
 148         //
 149         // int pc = codeStream.position;
 150         // Label endifLabel, falseLabel;
 151         // if (constant != NotAConstant) {
 152         // if (valueRequired)
 153         // codeStream.generateConstant(constant, implicitConversion);
 154         // codeStream.recordPositionsFrom(pc, this.sourceStart);
 155         // return;
 156         // }
 157         // Constant cst = condition.constant;
 158         // Constant condCst = condition.optimizedBooleanConstant();
 159         // boolean needTruePart =
 160         // !(((cst != NotAConstant) && (cst.booleanValue() == false))
 161         // || ((condCst != NotAConstant) && (condCst.booleanValue() == false)));
 162         // boolean needFalsePart =
 163         // !(((cst != NotAConstant) && (cst.booleanValue() == true))
 164         // || ((condCst != NotAConstant) && (condCst.booleanValue() == true)));
 165         // endifLabel = new Label(codeStream);
 166         //
 167         // // Generate code for the condition
 168         // boolean needConditionValue = (cst == NotAConstant) && (condCst ==
 169         // NotAConstant);
 170         // condition.generateOptimizedBoolean(
 171         // currentScope,
 172         // codeStream,
 173         // null,
 174         // (falseLabel = new Label(codeStream)),
 175         // needConditionValue);
 176         //
 177         // if (trueInitStateIndex != -1) {
 178         // codeStream.removeNotDefinitelyAssignedVariables(
 179         // currentScope,
 180         // trueInitStateIndex);
 181         // codeStream.addDefinitelyAssignedVariables(currentScope,
 182         // trueInitStateIndex);
 183         // }
 184         // // Then code generation
 185         // if (needTruePart) {
 186         // valueIfTrue.generateCode(currentScope, codeStream, valueRequired);
 187         // if (needFalsePart) {
 188         // // Jump over the else part
 189         // int position = codeStream.position;
 190         // codeStream.goto_(endifLabel);
 191         // codeStream.updateLastRecordedEndPC(position);
 192         // // Tune codestream stack size
 193         // if (valueRequired) {
 194         // codeStream.decrStackSize(returnTypeSlotSize);
 195         // }
 196         // }
 197         // }
 198         // if (needFalsePart) {
 199         // falseLabel.place();
 200         // if (falseInitStateIndex != -1) {
 201         // codeStream.removeNotDefinitelyAssignedVariables(
 202         // currentScope,
 203         // falseInitStateIndex);
 204         // codeStream.addDefinitelyAssignedVariables(currentScope,
 205         // falseInitStateIndex);
 206         // }
 207         // valueIfFalse.generateCode(currentScope, codeStream, valueRequired);
 208         // // End of if statement
 209         // endifLabel.place();
 210         // }
 211         // // May loose some local variable initializations : affecting the local
 212         // variable attributes
 213         // if (mergedInitStateIndex != -1) {
 214         // codeStream.removeNotDefinitelyAssignedVariables(
 215         // currentScope,
 216         // mergedInitStateIndex);
 217         // }
 218         // // implicit conversion
 219         // if (valueRequired)
 220         // codeStream.generateImplicitConversion(implicitConversion);
 221         // codeStream.recordPositionsFrom(pc, this.sourceStart);
 222         // }
 223         //
 224         // /**
 225         // * Optimized boolean code generation for the conditional operator ?:
 226         // */
 227         // public void generateOptimizedBoolean(
 228         // BlockScope currentScope,
 229         // CodeStream codeStream,
 230         // Label trueLabel,
 231         // Label falseLabel,
 232         // boolean valueRequired) {
 233         //
 234         // if ((constant != Constant.NotAConstant) && (constant.typeID() ==
 235         // T_boolean) // constant
 236         // || (valueIfTrue.implicitConversion >> 4) != T_boolean) { // non boolean
 237         // values
 238         // super.generateOptimizedBoolean(currentScope, codeStream, trueLabel,
 239         // falseLabel, valueRequired);
 240         // return;
 241         // }
 242         // Constant cst = condition.constant;
 243         // Constant condCst = condition.optimizedBooleanConstant();
 244         // boolean needTruePart =
 245         // !(((cst != NotAConstant) && (cst.booleanValue() == false))
 246         // || ((condCst != NotAConstant) && (condCst.booleanValue() == false)));
 247         // boolean needFalsePart =
 248         // !(((cst != NotAConstant) && (cst.booleanValue() == true))
 249         // || ((condCst != NotAConstant) && (condCst.booleanValue() == true)));
 250         //
 251         // Label internalFalseLabel, endifLabel = new Label(codeStream);
 252         //
 253         // // Generate code for the condition
 254         // boolean needConditionValue = (cst == NotAConstant) && (condCst ==
 255         // NotAConstant);
 256         // condition.generateOptimizedBoolean(
 257         // currentScope,
 258         // codeStream,
 259         // null,
 260         // internalFalseLabel = new Label(codeStream),
 261         // needConditionValue);
 262         //
 263         // if (trueInitStateIndex != -1) {
 264         // codeStream.removeNotDefinitelyAssignedVariables(
 265         // currentScope,
 266         // trueInitStateIndex);
 267         // codeStream.addDefinitelyAssignedVariables(currentScope,
 268         // trueInitStateIndex);
 269         // }
 270         // // Then code generation
 271         // if (needTruePart) {
 272         // valueIfTrue.generateOptimizedBoolean(currentScope, codeStream, trueLabel,
 273         // falseLabel, valueRequired);
 274         //
 275         // if (needFalsePart) {
 276         // // Jump over the else part
 277         // int position = codeStream.position;
 278         // codeStream.goto_(endifLabel);
 279         // codeStream.updateLastRecordedEndPC(position);
 280         // // No need to decrement codestream stack size
 281         // // since valueIfTrue was already consumed by branch bytecode
 282         // }
 283         // }
 284         // if (needFalsePart) {
 285         // internalFalseLabel.place();
 286         // if (falseInitStateIndex != -1) {
 287         // codeStream.removeNotDefinitelyAssignedVariables(
 288         // currentScope,
 289         // falseInitStateIndex);
 290         // codeStream.addDefinitelyAssignedVariables(currentScope,
 291         // falseInitStateIndex);
 292         // }
 293         // valueIfFalse.generateOptimizedBoolean(currentScope, codeStream,
 294         // trueLabel, falseLabel, valueRequired);
 295         //
 296         // // End of if statement
 297         // endifLabel.place();
 298         // }
 299         // // May loose some local variable initializations : affecting the local
 300         // variable attributes
 301         // if (mergedInitStateIndex != -1) {
 302         // codeStream.removeNotDefinitelyAssignedVariables(
 303         // currentScope,
 304         // mergedInitStateIndex);
 305         // }
 306         // // no implicit conversion for boolean values
 307         // codeStream.updateLastRecordedEndPC(codeStream.position);
 308         // }
 309         //
 310         // public Constant optimizedBooleanConstant() {
 311         //
 312         // return this.optimizedBooleanConstant == null ? this.constant :
 313         // this.optimizedBooleanConstant;
 314         // }
 315         //
 316         // public TypeBinding resolveType(BlockScope scope) {
 317         // // specs p.368
 318         // constant = NotAConstant;
 319         // TypeBinding conditionType = condition.resolveTypeExpecting(scope,
 320         // BooleanBinding);
 321         // TypeBinding valueIfTrueType = valueIfTrue.resolveType(scope);
 322         // TypeBinding valueIfFalseType = valueIfFalse.resolveType(scope);
 323         // if (conditionType == null || valueIfTrueType == null || valueIfFalseType
 324         // == null)
 325         // return null;
 326         //
 327         // // Propagate the constant value from the valueIfTrue and valueIFFalse
 328         // expression if it is possible
 329         // Constant condConstant, trueConstant, falseConstant;
 330         // if ((condConstant = condition.constant) != NotAConstant
 331         // && (trueConstant = valueIfTrue.constant) != NotAConstant
 332         // && (falseConstant = valueIfFalse.constant) != NotAConstant) {
 333         // // all terms are constant expression so we can propagate the constant
 334         // // from valueIFTrue or valueIfFalse to teh receiver constant
 335         // constant = condConstant.booleanValue() ? trueConstant : falseConstant;
 336         // }
 337         // if (valueIfTrueType == valueIfFalseType) { // harmed the implicit
 338         // conversion
 339         // valueIfTrue.implicitWidening(valueIfTrueType, valueIfTrueType);
 340         // valueIfFalse.implicitConversion = valueIfTrue.implicitConversion;
 341         // if (valueIfTrueType == LongBinding || valueIfTrueType == DoubleBinding) {
 342         // returnTypeSlotSize = 2;
 343         // }
 344         //
 345         // if (valueIfTrueType == BooleanBinding) {
 346         // this.optimizedIfTrueConstant = valueIfTrue.optimizedBooleanConstant();
 347         // this.optimizedIfFalseConstant = valueIfFalse.optimizedBooleanConstant();
 348         //
 349         // // Propagate the optimized boolean constant if possible
 350         // if ((condConstant = condition.optimizedBooleanConstant()) !=
 351         // NotAConstant) {
 352         //
 353         // this.optimizedBooleanConstant = condConstant.booleanValue()
 354         // ? optimizedIfTrueConstant
 355         // : optimizedIfFalseConstant;
 356         // }
 357         // }
 358         // return this.resolvedType = valueIfTrueType;
 359         // }
 360         // // Determine the return type depending on argument types
 361         // // Numeric types
 362         // if (valueIfTrueType.isNumericType() && valueIfFalseType.isNumericType())
 363         // {
 364         // // (Short x Byte) or (Byte x Short)"
 365         // if ((valueIfTrueType == ByteBinding && valueIfFalseType == ShortBinding)
 366         // || (valueIfTrueType == ShortBinding && valueIfFalseType == ByteBinding))
 367         // {
 368         // valueIfTrue.implicitWidening(ShortBinding, valueIfTrueType);
 369         // valueIfFalse.implicitWidening(ShortBinding, valueIfFalseType);
 370         // this.resolvedType = ShortBinding;
 371         // return ShortBinding;
 372         // }
 373         // // <Byte|Short|Char> x constant(Int) ---> <Byte|Short|Char> and
 374         // reciprocally
 375         // if ((valueIfTrueType == ByteBinding || valueIfTrueType == ShortBinding ||
 376         // valueIfTrueType == CharBinding)
 377         // && (valueIfFalseType == IntBinding
 378         // && valueIfFalse.isConstantValueOfTypeAssignableToType(valueIfFalseType,
 379         // valueIfTrueType))) {
 380         // valueIfTrue.implicitWidening(valueIfTrueType, valueIfTrueType);
 381         // valueIfFalse.implicitWidening(valueIfTrueType, valueIfFalseType);
 382         // this.resolvedType = valueIfTrueType;
 383         // return valueIfTrueType;
 384         // }
 385         // if ((valueIfFalseType == ByteBinding
 386         // || valueIfFalseType == ShortBinding
 387         // || valueIfFalseType == CharBinding)
 388         // && (valueIfTrueType == IntBinding
 389         // && valueIfTrue.isConstantValueOfTypeAssignableToType(valueIfTrueType,
 390         // valueIfFalseType))) {
 391         // valueIfTrue.implicitWidening(valueIfFalseType, valueIfTrueType);
 392         // valueIfFalse.implicitWidening(valueIfFalseType, valueIfFalseType);
 393         // this.resolvedType = valueIfFalseType;
 394         // return valueIfFalseType;
 395         // }
 396         // // Manual binary numeric promotion
 397         // // int
 398         // if (BaseTypeBinding.isNarrowing(valueIfTrueType.id, T_int)
 399         // && BaseTypeBinding.isNarrowing(valueIfFalseType.id, T_int)) {
 400         // valueIfTrue.implicitWidening(IntBinding, valueIfTrueType);
 401         // valueIfFalse.implicitWidening(IntBinding, valueIfFalseType);
 402         // this.resolvedType = IntBinding;
 403         // return IntBinding;
 404         // }
 405         // // long
 406         // if (BaseTypeBinding.isNarrowing(valueIfTrueType.id, T_long)
 407         // && BaseTypeBinding.isNarrowing(valueIfFalseType.id, T_long)) {
 408         // valueIfTrue.implicitWidening(LongBinding, valueIfTrueType);
 409         // valueIfFalse.implicitWidening(LongBinding, valueIfFalseType);
 410         // returnTypeSlotSize = 2;
 411         // this.resolvedType = LongBinding;
 412         // return LongBinding;
 413         // }
 414         // // float
 415         // if (BaseTypeBinding.isNarrowing(valueIfTrueType.id, T_float)
 416         // && BaseTypeBinding.isNarrowing(valueIfFalseType.id, T_float)) {
 417         // valueIfTrue.implicitWidening(FloatBinding, valueIfTrueType);
 418         // valueIfFalse.implicitWidening(FloatBinding, valueIfFalseType);
 419         // this.resolvedType = FloatBinding;
 420         // return FloatBinding;
 421         // }
 422         // // double
 423         // valueIfTrue.implicitWidening(DoubleBinding, valueIfTrueType);
 424         // valueIfFalse.implicitWidening(DoubleBinding, valueIfFalseType);
 425         // returnTypeSlotSize = 2;
 426         // this.resolvedType = DoubleBinding;
 427         // return DoubleBinding;
 428         // }
 429         // // Type references (null null is already tested)
 430         // if ((valueIfTrueType.isBaseType() && valueIfTrueType != NullBinding)
 431         // || (valueIfFalseType.isBaseType() && valueIfFalseType != NullBinding)) {
 432         // scope.problemReporter().conditionalArgumentsIncompatibleTypes(
 433         // this,
 434         // valueIfTrueType,
 435         // valueIfFalseType);
 436         // return null;
 437         // }
 438         // if (valueIfFalseType.isCompatibleWith(valueIfTrueType)) {
 439         // valueIfTrue.implicitWidening(valueIfTrueType, valueIfTrueType);
 440         // valueIfFalse.implicitWidening(valueIfTrueType, valueIfFalseType);
 441         // this.resolvedType = valueIfTrueType;
 442         // return valueIfTrueType;
 443         // }
 444         // if (valueIfTrueType.isCompatibleWith(valueIfFalseType)) {
 445         // valueIfTrue.implicitWidening(valueIfFalseType, valueIfTrueType);
 446         // valueIfFalse.implicitWidening(valueIfFalseType, valueIfFalseType);
 447         // this.resolvedType = valueIfFalseType;
 448         // return valueIfFalseType;
 449         // }
 450         // scope.problemReporter().conditionalArgumentsIncompatibleTypes(
 451         // this,
 452         // valueIfTrueType,
 453         // valueIfFalseType);
 454         // return null;
 455         // }
 456         public StringBuffer printExpressionNoParenthesis(int indent,
 457                         StringBuffer output) {
 458
 459                 condition.printExpression(indent, output).append(" ? "); //$NON-NLS-1$
 460                 valueIfTrue.printExpression(0, output).append(" : "); //$NON-NLS-1$
 461                 return valueIfFalse.printExpression(0, output);
 462         }
 463
 464         public String toStringExpressionNoParenthesis() {
 465                 return condition.toStringExpression() + " ? " + //$NON-NLS-1$
 466                                 valueIfTrue.toStringExpression() + " : " + //$NON-NLS-1$
 467                                 valueIfFalse.toStringExpression();
 468         }
 469
 470         public void traverse(ASTVisitor visitor, BlockScope scope) {
 471                 if (visitor.visit(this, scope)) {
 472                         condition.traverse(visitor, scope);
 473                         valueIfTrue.traverse(visitor, scope);
 474                         valueIfFalse.traverse(visitor, scope);
 475                 }
 476                 visitor.endVisit(this, scope);
 477         }
 478 }