net.sourceforge.phpeclipse/src/net/sourceforge/phpeclipse/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.phpeclipse.internal.compiler.ast;
  12
  13 import net.sourceforge.phpdt.internal.compiler.IAbstractSyntaxTreeVisitor;
  14 import net.sourceforge.phpdt.internal.compiler.codegen.Label;
  15 import net.sourceforge.phpdt.internal.compiler.flow.FlowContext;
  16 import net.sourceforge.phpdt.internal.compiler.flow.FlowInfo;
  17 import net.sourceforge.phpdt.internal.compiler.flow.UnconditionalFlowInfo;
  18 import net.sourceforge.phpdt.internal.compiler.impl.Constant;
  19 import net.sourceforge.phpdt.internal.compiler.lookup.BaseTypeBinding;
  20 import net.sourceforge.phpdt.internal.compiler.lookup.BlockScope;
  21 import net.sourceforge.phpdt.internal.compiler.lookup.TypeBinding;
  22
  23 public class ConditionalExpression extends OperatorExpression {
  24
  25         public Expression condition, valueIfTrue, valueIfFalse;
  26         public Constant optimizedBooleanConstant;
  27         public Constant optimizedIfTrueConstant;
  28         public Constant optimizedIfFalseConstant;
  29
  30         private int returnTypeSlotSize = 1;
  31
  32         // for local variables table attributes
  33         int trueInitStateIndex = -1;
  34         int falseInitStateIndex = -1;
  35         int mergedInitStateIndex = -1;
  36
  37         public ConditionalExpression(
  38                 Expression condition,
  39                 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(
  49                 BlockScope currentScope,
  50                 FlowContext flowContext,
  51                 FlowInfo flowInfo) {
  52
  53                 Constant cst = this.condition.optimizedBooleanConstant();
  54                 boolean isConditionOptimizedTrue = cst != NotAConstant && cst.booleanValue() == true;
  55                 boolean isConditionOptimizedFalse = cst != NotAConstant && cst.booleanValue() == false;
  56
  57                 int mode = flowInfo.reachMode();
  58                 flowInfo = condition.analyseCode(currentScope, flowContext, flowInfo, cst == NotAConstant);
  59
  60                 // process the if-true part
  61                 FlowInfo trueFlowInfo = flowInfo.initsWhenTrue().copy();
  62                 if (isConditionOptimizedFalse) {
  63                         trueFlowInfo.setReachMode(FlowInfo.UNREACHABLE);
  64                 }
  65                 trueInitStateIndex = currentScope.methodScope().recordInitializationStates(trueFlowInfo);
  66                 trueFlowInfo = valueIfTrue.analyseCode(currentScope, flowContext, trueFlowInfo);
  67
  68                 // process the if-false part
  69                 FlowInfo falseFlowInfo = flowInfo.initsWhenFalse().copy();
  70                 if (isConditionOptimizedTrue) {
  71                         falseFlowInfo.setReachMode(FlowInfo.UNREACHABLE);
  72                 }
  73                 falseInitStateIndex = currentScope.methodScope().recordInitializationStates(falseFlowInfo);
  74                 falseFlowInfo = valueIfFalse.analyseCode(currentScope, flowContext, falseFlowInfo);
  75
  76                 // merge if-true & if-false initializations
  77                 FlowInfo mergedInfo;
  78                 if (isConditionOptimizedTrue){
  79                         mergedInfo = trueFlowInfo.addPotentialInitializationsFrom(falseFlowInfo);
  80                 } else if (isConditionOptimizedFalse) {
  81                         mergedInfo = falseFlowInfo.addPotentialInitializationsFrom(trueFlowInfo);
  82                 } else {
  83                         // merge using a conditional info -  1GK2BLM
  84                         // if ((t && (v = t)) ? t : t && (v = f)) r = v;  -- ok
  85                         cst = this.optimizedIfTrueConstant;
  86                         boolean isValueIfTrueOptimizedTrue = cst != null && cst != NotAConstant && cst.booleanValue() == true;
  87                         boolean isValueIfTrueOptimizedFalse = cst != null && cst != NotAConstant && cst.booleanValue() == false;
  88
  89                         cst = this.optimizedIfFalseConstant;
  90                         boolean isValueIfFalseOptimizedTrue = cst != null && cst != NotAConstant && cst.booleanValue() == true;
  91                         boolean isValueIfFalseOptimizedFalse = cst != null && cst != NotAConstant && cst.booleanValue() == false;
  92
  93                         UnconditionalFlowInfo trueInfoWhenTrue = trueFlowInfo.initsWhenTrue().copy().unconditionalInits();
  94                         if (isValueIfTrueOptimizedFalse) trueInfoWhenTrue.setReachMode(FlowInfo.UNREACHABLE);
  95
  96                         UnconditionalFlowInfo falseInfoWhenTrue = falseFlowInfo.initsWhenTrue().copy().unconditionalInits();
  97                         if (isValueIfFalseOptimizedFalse) falseInfoWhenTrue.setReachMode(FlowInfo.UNREACHABLE);
  98
  99                         UnconditionalFlowInfo trueInfoWhenFalse = trueFlowInfo.initsWhenFalse().copy().unconditionalInits();
 100                         if (isValueIfTrueOptimizedTrue) trueInfoWhenFalse.setReachMode(FlowInfo.UNREACHABLE);
 101
 102                         UnconditionalFlowInfo falseInfoWhenFalse = falseFlowInfo.initsWhenFalse().copy().unconditionalInits();
 103                         if (isValueIfFalseOptimizedTrue) falseInfoWhenFalse.setReachMode(FlowInfo.UNREACHABLE);
 104
 105                         mergedInfo =
 106                                 FlowInfo.conditional(
 107                                         trueInfoWhenTrue.mergedWith(falseInfoWhenTrue),
 108                                         trueInfoWhenFalse.mergedWith(falseInfoWhenFalse));
 109                 }
 110                 mergedInitStateIndex =
 111                         currentScope.methodScope().recordInitializationStates(mergedInfo);
 112                 mergedInfo.setReachMode(mode);
 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.optimizedBooleanConstant();
 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 (trueInitStateIndex != -1) {
 156 //                      codeStream.removeNotDefinitelyAssignedVariables(
 157 //                              currentScope,
 158 //                              trueInitStateIndex);
 159 //                      codeStream.addDefinitelyAssignedVariables(currentScope, trueInitStateIndex);
 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 (falseInitStateIndex != -1) {
 178 //                              codeStream.removeNotDefinitelyAssignedVariables(
 179 //                                      currentScope,
 180 //                                      falseInitStateIndex);
 181 //                              codeStream.addDefinitelyAssignedVariables(currentScope, falseInitStateIndex);
 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 //              Constant cst = condition.constant;
 215 //              Constant condCst = condition.optimizedBooleanConstant();
 216 //              boolean needTruePart =
 217 //                      !(((cst != NotAConstant) && (cst.booleanValue() == false))
 218 //                              || ((condCst != NotAConstant) && (condCst.booleanValue() == false)));
 219 //              boolean needFalsePart =
 220 //                      !(((cst != NotAConstant) && (cst.booleanValue() == true))
 221 //                              || ((condCst != NotAConstant) && (condCst.booleanValue() == true)));
 222 //
 223 //              Label internalFalseLabel, endifLabel = new Label(codeStream);
 224 //
 225 //              // Generate code for the condition
 226 //              boolean needConditionValue = (cst == NotAConstant) && (condCst == NotAConstant);
 227 //              condition.generateOptimizedBoolean(
 228 //                              currentScope,
 229 //                              codeStream,
 230 //                              null,
 231 //                              internalFalseLabel = new Label(codeStream),
 232 //                              needConditionValue);
 233 //
 234 //              if (trueInitStateIndex != -1) {
 235 //                      codeStream.removeNotDefinitelyAssignedVariables(
 236 //                              currentScope,
 237 //                              trueInitStateIndex);
 238 //                      codeStream.addDefinitelyAssignedVariables(currentScope, trueInitStateIndex);
 239 //              }
 240 //              // Then code generation
 241 //              if (needTruePart) {
 242 //                      valueIfTrue.generateOptimizedBoolean(currentScope, codeStream, trueLabel, falseLabel, valueRequired);
 243 //
 244 //                      if (needFalsePart) {
 245 //                              // Jump over the else part
 246 //                              int position = codeStream.position;
 247 //                              codeStream.goto_(endifLabel);
 248 //                              codeStream.updateLastRecordedEndPC(position);
 249 //                              // No need to decrement codestream stack size
 250 //                              // since valueIfTrue was already consumed by branch bytecode
 251 //                      }
 252 //              }
 253 //              if (needFalsePart) {
 254 //                      internalFalseLabel.place();
 255 //                      if (falseInitStateIndex != -1) {
 256 //                              codeStream.removeNotDefinitelyAssignedVariables(
 257 //                                      currentScope,
 258 //                                      falseInitStateIndex);
 259 //                              codeStream.addDefinitelyAssignedVariables(currentScope, falseInitStateIndex);
 260 //                      }
 261 //                      valueIfFalse.generateOptimizedBoolean(currentScope, codeStream, trueLabel, falseLabel, valueRequired);
 262 //
 263 //                      // End of if statement
 264 //                      endifLabel.place();
 265 //              }
 266 //              // May loose some local variable initializations : affecting the local variable attributes
 267 //              if (mergedInitStateIndex != -1) {
 268 //                      codeStream.removeNotDefinitelyAssignedVariables(
 269 //                              currentScope,
 270 //                              mergedInitStateIndex);
 271 //              }
 272 //              // no implicit conversion for boolean values
 273 //              codeStream.updateLastRecordedEndPC(codeStream.position);
 274 //      }
 275 //
 276 //      public Constant optimizedBooleanConstant() {
 277 //
 278 //              return this.optimizedBooleanConstant == null ? this.constant : this.optimizedBooleanConstant;
 279 //      }
 280 //
 281 //      public TypeBinding resolveType(BlockScope scope) {
 282 //              // specs p.368
 283 //              constant = NotAConstant;
 284 //              TypeBinding conditionType = condition.resolveTypeExpecting(scope, BooleanBinding);
 285 //              TypeBinding valueIfTrueType = valueIfTrue.resolveType(scope);
 286 //              TypeBinding valueIfFalseType = valueIfFalse.resolveType(scope);
 287 //              if (conditionType == null || valueIfTrueType == null || valueIfFalseType == null)
 288 //                      return null;
 289 //
 290 //              // Propagate the constant value from the valueIfTrue and valueIFFalse expression if it is possible
 291 //              Constant condConstant, trueConstant, falseConstant;
 292 //              if ((condConstant = condition.constant) != NotAConstant
 293 //                      && (trueConstant = valueIfTrue.constant) != NotAConstant
 294 //                      && (falseConstant = valueIfFalse.constant) != NotAConstant) {
 295 //                      // all terms are constant expression so we can propagate the constant
 296 //                      // from valueIFTrue or valueIfFalse to teh receiver constant
 297 //                      constant = condConstant.booleanValue() ? trueConstant : falseConstant;
 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 //
 306 //                      if (valueIfTrueType == BooleanBinding) {
 307 //                              this.optimizedIfTrueConstant = valueIfTrue.optimizedBooleanConstant();
 308 //                              this.optimizedIfFalseConstant = valueIfFalse.optimizedBooleanConstant();
 309 //
 310 //                              // Propagate the optimized boolean constant if possible
 311 //                              if ((condConstant = condition.optimizedBooleanConstant()) != NotAConstant) {
 312 //
 313 //                                      this.optimizedBooleanConstant = condConstant.booleanValue()
 314 //                                              ? optimizedIfTrueConstant
 315 //                                              : optimizedIfFalseConstant;
 316 //                              }
 317 //                      }
 318 //                      return this.resolvedType = valueIfTrueType;
 319 //              }
 320 //              // Determine the return type depending on argument types
 321 //              // Numeric types
 322 //              if (valueIfTrueType.isNumericType() && valueIfFalseType.isNumericType()) {
 323 //                      // (Short x Byte) or (Byte x Short)"
 324 //                      if ((valueIfTrueType == ByteBinding && valueIfFalseType == ShortBinding)
 325 //                              || (valueIfTrueType == ShortBinding && valueIfFalseType == ByteBinding)) {
 326 //                              valueIfTrue.implicitWidening(ShortBinding, valueIfTrueType);
 327 //                              valueIfFalse.implicitWidening(ShortBinding, valueIfFalseType);
 328 //                              this.resolvedType = ShortBinding;
 329 //                              return ShortBinding;
 330 //                      }
 331 //                      // <Byte|Short|Char> x constant(Int)  ---> <Byte|Short|Char>   and reciprocally
 332 //                      if ((valueIfTrueType == ByteBinding || valueIfTrueType == ShortBinding || valueIfTrueType == CharBinding)
 333 //                              && (valueIfFalseType == IntBinding
 334 //                                      && valueIfFalse.isConstantValueOfTypeAssignableToType(valueIfFalseType, valueIfTrueType))) {
 335 //                              valueIfTrue.implicitWidening(valueIfTrueType, valueIfTrueType);
 336 //                              valueIfFalse.implicitWidening(valueIfTrueType, valueIfFalseType);
 337 //                              this.resolvedType = valueIfTrueType;
 338 //                              return valueIfTrueType;
 339 //                      }
 340 //                      if ((valueIfFalseType == ByteBinding
 341 //                              || valueIfFalseType == ShortBinding
 342 //                              || valueIfFalseType == CharBinding)
 343 //                              && (valueIfTrueType == IntBinding
 344 //                                      && valueIfTrue.isConstantValueOfTypeAssignableToType(valueIfTrueType, valueIfFalseType))) {
 345 //                              valueIfTrue.implicitWidening(valueIfFalseType, valueIfTrueType);
 346 //                              valueIfFalse.implicitWidening(valueIfFalseType, valueIfFalseType);
 347 //                              this.resolvedType = valueIfFalseType;
 348 //                              return valueIfFalseType;
 349 //                      }
 350 //                      // Manual binary numeric promotion
 351 //                      // int
 352 //                      if (BaseTypeBinding.isNarrowing(valueIfTrueType.id, T_int)
 353 //                              && BaseTypeBinding.isNarrowing(valueIfFalseType.id, T_int)) {
 354 //                              valueIfTrue.implicitWidening(IntBinding, valueIfTrueType);
 355 //                              valueIfFalse.implicitWidening(IntBinding, valueIfFalseType);
 356 //                              this.resolvedType = IntBinding;
 357 //                              return IntBinding;
 358 //                      }
 359 //                      // long
 360 //                      if (BaseTypeBinding.isNarrowing(valueIfTrueType.id, T_long)
 361 //                              && BaseTypeBinding.isNarrowing(valueIfFalseType.id, T_long)) {
 362 //                              valueIfTrue.implicitWidening(LongBinding, valueIfTrueType);
 363 //                              valueIfFalse.implicitWidening(LongBinding, valueIfFalseType);
 364 //                              returnTypeSlotSize = 2;
 365 //                              this.resolvedType = LongBinding;
 366 //                              return LongBinding;
 367 //                      }
 368 //                      // float
 369 //                      if (BaseTypeBinding.isNarrowing(valueIfTrueType.id, T_float)
 370 //                              && BaseTypeBinding.isNarrowing(valueIfFalseType.id, T_float)) {
 371 //                              valueIfTrue.implicitWidening(FloatBinding, valueIfTrueType);
 372 //                              valueIfFalse.implicitWidening(FloatBinding, valueIfFalseType);
 373 //                              this.resolvedType = FloatBinding;
 374 //                              return FloatBinding;
 375 //                      }
 376 //                      // double
 377 //                      valueIfTrue.implicitWidening(DoubleBinding, valueIfTrueType);
 378 //                      valueIfFalse.implicitWidening(DoubleBinding, valueIfFalseType);
 379 //                      returnTypeSlotSize = 2;
 380 //                      this.resolvedType = DoubleBinding;
 381 //                      return DoubleBinding;
 382 //              }
 383 //              // Type references (null null is already tested)
 384 //              if ((valueIfTrueType.isBaseType() && valueIfTrueType != NullBinding)
 385 //                      || (valueIfFalseType.isBaseType() && valueIfFalseType != NullBinding)) {
 386 //                      scope.problemReporter().conditionalArgumentsIncompatibleTypes(
 387 //                              this,
 388 //                              valueIfTrueType,
 389 //                              valueIfFalseType);
 390 //                      return null;
 391 //              }
 392 //              if (valueIfFalseType.isCompatibleWith(valueIfTrueType)) {
 393 //                      valueIfTrue.implicitWidening(valueIfTrueType, valueIfTrueType);
 394 //                      valueIfFalse.implicitWidening(valueIfTrueType, valueIfFalseType);
 395 //                      this.resolvedType = valueIfTrueType;
 396 //                      return valueIfTrueType;
 397 //              }
 398 //              if (valueIfTrueType.isCompatibleWith(valueIfFalseType)) {
 399 //                      valueIfTrue.implicitWidening(valueIfFalseType, valueIfTrueType);
 400 //                      valueIfFalse.implicitWidening(valueIfFalseType, valueIfFalseType);
 401 //                      this.resolvedType = valueIfFalseType;
 402 //                      return valueIfFalseType;
 403 //              }
 404 //              scope.problemReporter().conditionalArgumentsIncompatibleTypes(
 405 //                      this,
 406 //                      valueIfTrueType,
 407 //                      valueIfFalseType);
 408 //              return null;
 409 //      }
 410
 411         public String toStringExpressionNoParenthesis() {
 412                 return condition.toStringExpression() + " ? " + //$NON-NLS-1$
 413                 valueIfTrue.toStringExpression() + " : " + //$NON-NLS-1$
 414                 valueIfFalse.toStringExpression();
 415         }
 416
 417         public void traverse(IAbstractSyntaxTreeVisitor visitor, BlockScope scope) {
 418                 if (visitor.visit(this, scope)) {
 419                         condition.traverse(visitor, scope);
 420                         valueIfTrue.traverse(visitor, scope);
 421                         valueIfFalse.traverse(visitor, scope);
 422                 }
 423                 visitor.endVisit(this, scope);
 424         }
 425 }