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   1 /*******************************************************************************
   2  * Copyright (c) 2000, 2001, 2002 International Business Machines Corp. and others.
   3  * All rights reserved. This program and the accompanying materials
   4  * are made available under the terms of the Common Public License v0.5
   5  * which accompanies this distribution, and is available at
   6  * http://www.eclipse.org/legal/cpl-v05.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.IAbstractSyntaxTreeVisitor;
  14 import net.sourceforge.phpdt.internal.compiler.impl.*;
  15 import net.sourceforge.phpdt.internal.compiler.codegen.*;
  16 import net.sourceforge.phpdt.internal.compiler.flow.*;
  17 import net.sourceforge.phpdt.internal.compiler.lookup.*;
  18
  19 public class ConditionalExpression extends OperatorExpression {
  20
  21         public Expression condition, valueIfTrue, valueIfFalse;
  22         private int returnTypeSlotSize = 1;
  23
  24         // for local variables table attributes
  25         int thenInitStateIndex = -1;
  26         int elseInitStateIndex = -1;
  27         int mergedInitStateIndex = -1;
  28
  29         public ConditionalExpression(
  30                 Expression condition,
  31                 Expression valueIfTrue,
  32                 Expression valueIfFalse) {
  33                 this.condition = condition;
  34                 this.valueIfTrue = valueIfTrue;
  35                 this.valueIfFalse = valueIfFalse;
  36                 sourceStart = condition.sourceStart;
  37                 sourceEnd = valueIfFalse.sourceEnd;
  38         }
  39
  40         public FlowInfo analyseCode(
  41                 BlockScope currentScope,
  42                 FlowContext flowContext,
  43                 FlowInfo flowInfo) {
  44
  45                 Constant conditionConstant = condition.conditionalConstant();
  46
  47                 flowInfo = condition.analyseCode(currentScope, flowContext, flowInfo, conditionConstant == NotAConstant);
  48
  49                 if (conditionConstant != NotAConstant) {
  50                         if (conditionConstant.booleanValue() == true) {
  51                                 // TRUE ? left : right
  52                                 FlowInfo resultInfo =
  53                                         valueIfTrue.analyseCode(currentScope, flowContext, flowInfo.initsWhenTrue().unconditionalInits());
  54                                 // analyse valueIfFalse, but do not take into account any of its infos
  55                                 valueIfFalse.analyseCode(
  56                                         currentScope,
  57                                         flowContext,
  58                                         flowInfo.initsWhenFalse().copy().unconditionalInits().markAsFakeReachable(true));
  59                                 mergedInitStateIndex =
  60                                         currentScope.methodScope().recordInitializationStates(resultInfo);
  61                                 return resultInfo;
  62                         } else {
  63                                 // FALSE ? left : right
  64                                 // analyse valueIfTrue, but do not take into account any of its infos
  65                                 valueIfTrue.analyseCode(
  66                                         currentScope,
  67                                         flowContext,
  68                                         flowInfo.initsWhenTrue().copy().unconditionalInits().markAsFakeReachable(true));
  69                                 FlowInfo mergeInfo =
  70                                         valueIfFalse.analyseCode(currentScope, flowContext, flowInfo.initsWhenFalse().unconditionalInits());
  71                                 mergedInitStateIndex =
  72                                         currentScope.methodScope().recordInitializationStates(mergeInfo);
  73                                 return mergeInfo;
  74                         }
  75                 }
  76
  77                 // store a copy of the merged info, so as to compute the local variable attributes afterwards
  78                 FlowInfo trueInfo = flowInfo.initsWhenTrue();
  79                 thenInitStateIndex =
  80                         currentScope.methodScope().recordInitializationStates(trueInfo);
  81                 FlowInfo falseInfo = flowInfo.initsWhenFalse();
  82                 elseInitStateIndex =
  83                         currentScope.methodScope().recordInitializationStates(falseInfo);
  84
  85                 // propagate analysis
  86                 trueInfo = valueIfTrue.analyseCode(currentScope, flowContext, trueInfo.copy());
  87                 falseInfo =
  88                         valueIfFalse.analyseCode(currentScope, flowContext, falseInfo.copy());
  89
  90                 // merge back using a conditional info -  1GK2BLM
  91                 // if ((t && (v = t)) ? t : t && (v = f)) r = v;  -- ok
  92                 FlowInfo mergedInfo =
  93                         FlowInfo.conditional(
  94                                 trueInfo.initsWhenTrue().copy().unconditionalInits().mergedWith( // must copy, since could be shared with trueInfo.initsWhenFalse()...
  95                                         falseInfo.initsWhenTrue().copy().unconditionalInits()),
  96                                 trueInfo.initsWhenFalse().unconditionalInits().mergedWith(
  97                                         falseInfo.initsWhenFalse().unconditionalInits()));
  98                 /*
  99                         FlowInfo mergedInfo = valueIfTrue.analyseCode(
 100                                 currentScope,
 101                                 flowContext,
 102                                 flowInfo.initsWhenTrue().copy()).
 103                                         unconditionalInits().
 104                                                 mergedWith(
 105                                                         valueIfFalse.analyseCode(
 106                                                                 currentScope,
 107                                                                 flowContext,
 108                                                                 flowInfo.initsWhenFalse().copy()).
 109                                                                         unconditionalInits());
 110                 */
 111                 mergedInitStateIndex =
 112                         currentScope.methodScope().recordInitializationStates(mergedInfo);
 113                 return mergedInfo;
 114         }
 115
 116         /**
 117          * Code generation for the conditional operator ?:
 118          *
 119          * @param currentScope org.eclipse.jdt.internal.compiler.lookup.BlockScope
 120          * @param codeStream org.eclipse.jdt.internal.compiler.codegen.CodeStream
 121          * @param valueRequired boolean
 122         */
 123         public void generateCode(
 124                 BlockScope currentScope,
 125                 CodeStream codeStream,
 126                 boolean valueRequired) {
 127
 128                 int pc = codeStream.position;
 129                 Label endifLabel, falseLabel;
 130                 if (constant != NotAConstant) {
 131                         if (valueRequired)
 132                                 codeStream.generateConstant(constant, implicitConversion);
 133                         codeStream.recordPositionsFrom(pc, this.sourceStart);
 134                         return;
 135                 }
 136                 Constant cst = condition.constant;
 137                 Constant condCst = condition.conditionalConstant();
 138                 boolean needTruePart =
 139                         !(((cst != NotAConstant) && (cst.booleanValue() == false))
 140                                 || ((condCst != NotAConstant) && (condCst.booleanValue() == false)));
 141                 boolean needFalsePart =
 142                         !(((cst != NotAConstant) && (cst.booleanValue() == true))
 143                                 || ((condCst != NotAConstant) && (condCst.booleanValue() == true)));
 144                 endifLabel = new Label(codeStream);
 145
 146                 // Generate code for the condition
 147                 boolean needConditionValue = (cst == NotAConstant) && (condCst == NotAConstant);
 148                 condition.generateOptimizedBoolean(
 149                         currentScope,
 150                         codeStream,
 151                         null,
 152                         (falseLabel = new Label(codeStream)),
 153                         needConditionValue);
 154
 155                 if (thenInitStateIndex != -1) {
 156                         codeStream.removeNotDefinitelyAssignedVariables(
 157                                 currentScope,
 158                                 thenInitStateIndex);
 159                         codeStream.addDefinitelyAssignedVariables(currentScope, thenInitStateIndex);
 160                 }
 161                 // Then code generation
 162                 if (needTruePart) {
 163                         valueIfTrue.generateCode(currentScope, codeStream, valueRequired);
 164                         if (needFalsePart) {
 165                                 // Jump over the else part
 166                                 int position = codeStream.position;
 167                                 codeStream.goto_(endifLabel);
 168                                 codeStream.updateLastRecordedEndPC(position);
 169                                 // Tune codestream stack size
 170                                 if (valueRequired) {
 171                                         codeStream.decrStackSize(returnTypeSlotSize);
 172                                 }
 173                         }
 174                 }
 175                 if (needFalsePart) {
 176                         falseLabel.place();
 177                         if (elseInitStateIndex != -1) {
 178                                 codeStream.removeNotDefinitelyAssignedVariables(
 179                                         currentScope,
 180                                         elseInitStateIndex);
 181                                 codeStream.addDefinitelyAssignedVariables(currentScope, elseInitStateIndex);
 182                         }
 183                         valueIfFalse.generateCode(currentScope, codeStream, valueRequired);
 184                         // End of if statement
 185                         endifLabel.place();
 186                 }
 187                 // May loose some local variable initializations : affecting the local variable attributes
 188                 if (mergedInitStateIndex != -1) {
 189                         codeStream.removeNotDefinitelyAssignedVariables(
 190                                 currentScope,
 191                                 mergedInitStateIndex);
 192                 }
 193                 // implicit conversion
 194                 if (valueRequired)
 195                         codeStream.generateImplicitConversion(implicitConversion);
 196                 codeStream.recordPositionsFrom(pc, this.sourceStart);
 197         }
 198
 199         /**
 200          * Optimized boolean code generation for the conditional operator ?:
 201         */
 202         public void generateOptimizedBoolean(
 203                 BlockScope currentScope,
 204                 CodeStream codeStream,
 205                 Label trueLabel,
 206                 Label falseLabel,
 207                 boolean valueRequired) {
 208
 209                 if ((constant != Constant.NotAConstant) && (constant.typeID() == T_boolean) // constant
 210                         || (valueIfTrue.implicitConversion >> 4) != T_boolean) { // non boolean values
 211                         super.generateOptimizedBoolean(currentScope, codeStream, trueLabel, falseLabel, valueRequired);
 212                         return;
 213                 }
 214                 int pc = codeStream.position;
 215                 Constant cst = condition.constant;
 216                 Constant condCst = condition.conditionalConstant();
 217                 boolean needTruePart =
 218                         !(((cst != NotAConstant) && (cst.booleanValue() == false))
 219                                 || ((condCst != NotAConstant) && (condCst.booleanValue() == false)));
 220                 boolean needFalsePart =
 221                         !(((cst != NotAConstant) && (cst.booleanValue() == true))
 222                                 || ((condCst != NotAConstant) && (condCst.booleanValue() == true)));
 223
 224                 Label internalFalseLabel, endifLabel = new Label(codeStream);
 225
 226                 // Generate code for the condition
 227                 boolean needConditionValue = (cst == NotAConstant) && (condCst == NotAConstant);
 228                 condition.generateOptimizedBoolean(
 229                                 currentScope,
 230                                 codeStream,
 231                                 null,
 232                                 internalFalseLabel = new Label(codeStream),
 233                                 needConditionValue);
 234
 235                 if (thenInitStateIndex != -1) {
 236                         codeStream.removeNotDefinitelyAssignedVariables(
 237                                 currentScope,
 238                                 thenInitStateIndex);
 239                         codeStream.addDefinitelyAssignedVariables(currentScope, thenInitStateIndex);
 240                 }
 241                 // Then code generation
 242                 if (needTruePart) {
 243                         valueIfTrue.generateOptimizedBoolean(currentScope, codeStream, trueLabel, falseLabel, valueRequired);
 244
 245                         if (needFalsePart) {
 246                                 // Jump over the else part
 247                                 int position = codeStream.position;
 248                                 codeStream.goto_(endifLabel);
 249                                 codeStream.updateLastRecordedEndPC(position);
 250                                 // Tune codestream stack size
 251                                 //if (valueRequired) {
 252                                 //      codeStream.decrStackSize(returnTypeSlotSize);
 253                                 //}
 254                         }
 255                 }
 256                 if (needFalsePart) {
 257                         internalFalseLabel.place();
 258                         if (elseInitStateIndex != -1) {
 259                                 codeStream.removeNotDefinitelyAssignedVariables(
 260                                         currentScope,
 261                                         elseInitStateIndex);
 262                                 codeStream.addDefinitelyAssignedVariables(currentScope, elseInitStateIndex);
 263                         }
 264                         valueIfFalse.generateOptimizedBoolean(currentScope, codeStream, trueLabel, falseLabel, valueRequired);
 265
 266                         // End of if statement
 267                         endifLabel.place();
 268                 }
 269                 // May loose some local variable initializations : affecting the local variable attributes
 270                 if (mergedInitStateIndex != -1) {
 271                         codeStream.removeNotDefinitelyAssignedVariables(
 272                                 currentScope,
 273                                 mergedInitStateIndex);
 274                 }
 275                 // no implicit conversion for boolean values
 276                 codeStream.recordPositionsFrom(pc, this.sourceStart);
 277         }
 278
 279         public TypeBinding resolveType(BlockScope scope) {
 280                 // specs p.368
 281                 constant = NotAConstant;
 282                 TypeBinding conditionType = condition.resolveTypeExpecting(scope, BooleanBinding);
 283                 TypeBinding valueIfTrueType = valueIfTrue.resolveType(scope);
 284                 TypeBinding valueIfFalseType = valueIfFalse.resolveType(scope);
 285                 if (conditionType == null || valueIfTrueType == null || valueIfFalseType == null)
 286                         return null;
 287
 288                 // Propagate the constant value from the valueIfTrue and valueIFFalse expression if it is possible
 289                 if (condition.constant != NotAConstant
 290                         && valueIfTrue.constant != NotAConstant
 291                         && valueIfFalse.constant != NotAConstant) {
 292                         // all terms are constant expression so we can propagate the constant
 293                         // from valueIFTrue or valueIfFalse to teh receiver constant
 294                         constant =
 295                                 (condition.constant.booleanValue())
 296                                         ? valueIfTrue.constant
 297                                         : valueIfFalse.constant;
 298                 }
 299                 if (valueIfTrueType == valueIfFalseType) { // harmed the implicit conversion
 300                         valueIfTrue.implicitWidening(valueIfTrueType, valueIfTrueType);
 301                         valueIfFalse.implicitConversion = valueIfTrue.implicitConversion;
 302                         if (valueIfTrueType == LongBinding || valueIfTrueType == DoubleBinding) {
 303                                 returnTypeSlotSize = 2;
 304                         }
 305                         this.typeBinding = valueIfTrueType;
 306                         return valueIfTrueType;
 307                 }
 308                 // Determine the return type depending on argument types
 309                 // Numeric types
 310                 if (valueIfTrueType.isNumericType() && valueIfFalseType.isNumericType()) {
 311                         // (Short x Byte) or (Byte x Short)"
 312                         if ((valueIfTrueType == ByteBinding && valueIfFalseType == ShortBinding)
 313                                 || (valueIfTrueType == ShortBinding && valueIfFalseType == ByteBinding)) {
 314                                 valueIfTrue.implicitWidening(ShortBinding, valueIfTrueType);
 315                                 valueIfFalse.implicitWidening(ShortBinding, valueIfFalseType);
 316                                 this.typeBinding = ShortBinding;
 317                                 return ShortBinding;
 318                         }
 319                         // <Byte|Short|Char> x constant(Int)  ---> <Byte|Short|Char>   and reciprocally
 320                         if ((valueIfTrueType == ByteBinding || valueIfTrueType == ShortBinding || valueIfTrueType == CharBinding)
 321                                 && (valueIfFalseType == IntBinding
 322                                         && valueIfFalse.isConstantValueOfTypeAssignableToType(valueIfFalseType, valueIfTrueType))) {
 323                                 valueIfTrue.implicitWidening(valueIfTrueType, valueIfTrueType);
 324                                 valueIfFalse.implicitWidening(valueIfTrueType, valueIfFalseType);
 325                                 this.typeBinding = valueIfTrueType;
 326                                 return valueIfTrueType;
 327                         }
 328                         if ((valueIfFalseType == ByteBinding
 329                                 || valueIfFalseType == ShortBinding
 330                                 || valueIfFalseType == CharBinding)
 331                                 && (valueIfTrueType == IntBinding
 332                                         && valueIfTrue.isConstantValueOfTypeAssignableToType(valueIfTrueType, valueIfFalseType))) {
 333                                 valueIfTrue.implicitWidening(valueIfFalseType, valueIfTrueType);
 334                                 valueIfFalse.implicitWidening(valueIfFalseType, valueIfFalseType);
 335                                 this.typeBinding = valueIfFalseType;
 336                                 return valueIfFalseType;
 337                         }
 338                         // Manual binary numeric promotion
 339                         // int
 340                         if (BaseTypeBinding.isNarrowing(valueIfTrueType.id, T_int)
 341                                 && BaseTypeBinding.isNarrowing(valueIfFalseType.id, T_int)) {
 342                                 valueIfTrue.implicitWidening(IntBinding, valueIfTrueType);
 343                                 valueIfFalse.implicitWidening(IntBinding, valueIfFalseType);
 344                                 this.typeBinding = IntBinding;
 345                                 return IntBinding;
 346                         }
 347                         // long
 348                         if (BaseTypeBinding.isNarrowing(valueIfTrueType.id, T_long)
 349                                 && BaseTypeBinding.isNarrowing(valueIfFalseType.id, T_long)) {
 350                                 valueIfTrue.implicitWidening(LongBinding, valueIfTrueType);
 351                                 valueIfFalse.implicitWidening(LongBinding, valueIfFalseType);
 352                                 returnTypeSlotSize = 2;
 353                                 this.typeBinding = LongBinding;
 354                                 return LongBinding;
 355                         }
 356                         // float
 357                         if (BaseTypeBinding.isNarrowing(valueIfTrueType.id, T_float)
 358                                 && BaseTypeBinding.isNarrowing(valueIfFalseType.id, T_float)) {
 359                                 valueIfTrue.implicitWidening(FloatBinding, valueIfTrueType);
 360                                 valueIfFalse.implicitWidening(FloatBinding, valueIfFalseType);
 361                                 this.typeBinding = FloatBinding;
 362                                 return FloatBinding;
 363                         }
 364                         // double
 365                         valueIfTrue.implicitWidening(DoubleBinding, valueIfTrueType);
 366                         valueIfFalse.implicitWidening(DoubleBinding, valueIfFalseType);
 367                         returnTypeSlotSize = 2;
 368                         this.typeBinding = DoubleBinding;
 369                         return DoubleBinding;
 370                 }
 371                 // Type references (null null is already tested)
 372                 if ((valueIfTrueType.isBaseType() && valueIfTrueType != NullBinding)
 373                         || (valueIfFalseType.isBaseType() && valueIfFalseType != NullBinding)) {
 374                         scope.problemReporter().conditionalArgumentsIncompatibleTypes(
 375                                 this,
 376                                 valueIfTrueType,
 377                                 valueIfFalseType);
 378                         return null;
 379                 }
 380                 if (scope.areTypesCompatible(valueIfFalseType, valueIfTrueType)) {
 381                         valueIfTrue.implicitWidening(valueIfTrueType, valueIfTrueType);
 382                         valueIfFalse.implicitWidening(valueIfTrueType, valueIfFalseType);
 383                         this.typeBinding = valueIfTrueType;
 384                         return valueIfTrueType;
 385                 }
 386                 if (scope.areTypesCompatible(valueIfTrueType, valueIfFalseType)) {
 387                         valueIfTrue.implicitWidening(valueIfFalseType, valueIfTrueType);
 388                         valueIfFalse.implicitWidening(valueIfFalseType, valueIfFalseType);
 389                         this.typeBinding = valueIfFalseType;
 390                         return valueIfFalseType;
 391                 }
 392                 scope.problemReporter().conditionalArgumentsIncompatibleTypes(
 393                         this,
 394                         valueIfTrueType,
 395                         valueIfFalseType);
 396                 return null;
 397         }
 398
 399         public String toStringExpressionNoParenthesis() {
 400                 return condition.toStringExpression() + " ? " + //$NON-NLS-1$
 401                 valueIfTrue.toStringExpression() + " : " + //$NON-NLS-1$
 402                 valueIfFalse.toStringExpression();
 403         }
 404
 405         public void traverse(IAbstractSyntaxTreeVisitor visitor, BlockScope scope) {
 406                 if (visitor.visit(this, scope)) {
 407                         condition.traverse(visitor, scope);
 408                         valueIfTrue.traverse(visitor, scope);
 409                         valueIfFalse.traverse(visitor, scope);
 410                 }
 411                 visitor.endVisit(this, scope);
 412         }
 413 }