net.sourceforge.phpeclipse/src/net/sourceforge/phpdt/internal/compiler/ast/ForStatement.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.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.LoopingFlowContext;
  18 import net.sourceforge.phpdt.internal.compiler.impl.Constant;
  19 import net.sourceforge.phpdt.internal.compiler.lookup.BlockScope;
  20 import net.sourceforge.phpdt.internal.compiler.lookup.TypeBinding;
  21
  22 public class ForStatement extends Statement {
  23
  24         public Statement[] initializations;
  25
  26         public Expression condition;
  27
  28         public Statement[] increments;
  29
  30         public Statement action;
  31
  32         // when there is no local declaration, there is no need of a new scope
  33         // scope is positionned either to a new scope, or to the "upper"scope (see
  34         // resolveType)
  35         public boolean neededScope;
  36
  37         public BlockScope scope;
  38
  39         private Label breakLabel, continueLabel;
  40
  41         // for local variables table attributes
  42         int preCondInitStateIndex = -1;
  43
  44         int condIfTrueInitStateIndex = -1;
  45
  46         int mergedInitStateIndex = -1;
  47
  48         public ForStatement(Statement[] initializations, Expression condition,
  49                         Statement[] increments, Statement action, boolean neededScope,
  50                         int s, int e) {
  51
  52                 this.sourceStart = s;
  53                 this.sourceEnd = e;
  54                 this.initializations = initializations;
  55                 this.condition = condition;
  56                 this.increments = increments;
  57                 this.action = action;
  58                 this.neededScope = neededScope;
  59         }
  60
  61         public FlowInfo analyseCode(BlockScope currentScope,
  62                         FlowContext flowContext, FlowInfo flowInfo) {
  63
  64                 breakLabel = new Label();
  65                 continueLabel = new Label();
  66
  67                 // process the initializations
  68                 if (initializations != null) {
  69                         int count = initializations.length, i = 0;
  70                         while (i < count) {
  71                                 flowInfo = initializations[i++].analyseCode(scope, flowContext,
  72                                                 flowInfo);
  73                         }
  74                 }
  75                 preCondInitStateIndex = currentScope.methodScope()
  76                                 .recordInitializationStates(flowInfo);
  77
  78                 Constant cst = this.condition == null ? null : this.condition.constant;
  79                 boolean isConditionTrue = cst == null
  80                                 || (cst != NotAConstant && cst.booleanValue() == true);
  81                 boolean isConditionFalse = cst != null
  82                                 && (cst != NotAConstant && cst.booleanValue() == false);
  83
  84                 cst = this.condition == null ? null : this.condition
  85                                 .optimizedBooleanConstant();
  86                 boolean isConditionOptimizedTrue = cst == null
  87                                 || (cst != NotAConstant && cst.booleanValue() == true);
  88                 boolean isConditionOptimizedFalse = cst != null
  89                                 && (cst != NotAConstant && cst.booleanValue() == false);
  90
  91                 // process the condition
  92                 LoopingFlowContext condLoopContext = null;
  93                 if (condition != null) {
  94                         if (!isConditionTrue) {
  95                                 flowInfo = condition.analyseCode(scope,
  96                                                 (condLoopContext = new LoopingFlowContext(flowContext,
  97                                                                 this, null, null, scope)), flowInfo);
  98                         }
  99                 }
 100
 101                 // process the action
 102                 LoopingFlowContext loopingContext;
 103                 FlowInfo actionInfo;
 104                 if (action == null) {
 105                         // || (action.isEmptyBlock() &&
 106                         // currentScope.environment().options.complianceLevel <=
 107                         // CompilerOptions.JDK1_3)) {
 108                         if (condLoopContext != null)
 109                                 condLoopContext.complainOnFinalAssignmentsInLoop(scope,
 110                                                 flowInfo);
 111                         if (isConditionTrue) {
 112                                 return FlowInfo.DEAD_END;
 113                         } else {
 114                                 if (isConditionFalse) {
 115                                         continueLabel = null; // for(;false;p());
 116                                 }
 117                                 actionInfo = flowInfo.initsWhenTrue().copy();
 118                                 loopingContext = new LoopingFlowContext(flowContext, this,
 119                                                 breakLabel, continueLabel, scope);
 120                         }
 121                 } else {
 122                         loopingContext = new LoopingFlowContext(flowContext, this,
 123                                         breakLabel, continueLabel, scope);
 124                         FlowInfo initsWhenTrue = flowInfo.initsWhenTrue();
 125                         condIfTrueInitStateIndex = currentScope.methodScope()
 126                                         .recordInitializationStates(initsWhenTrue);
 127
 128                         if (isConditionFalse) {
 129                                 actionInfo = FlowInfo.DEAD_END;
 130                         } else {
 131                                 actionInfo = initsWhenTrue.copy();
 132                                 if (isConditionOptimizedFalse) {
 133                                         actionInfo.setReachMode(FlowInfo.UNREACHABLE);
 134                                 }
 135                         }
 136                         if (!actionInfo.complainIfUnreachable(action, scope, false)) {
 137                                 actionInfo = action.analyseCode(scope, loopingContext,
 138                                                 actionInfo);
 139                         }
 140
 141                         // code generation can be optimized when no need to continue in the
 142                         // loop
 143                         if (!actionInfo.isReachable()
 144                                         && !loopingContext.initsOnContinue.isReachable()) {
 145                                 continueLabel = null;
 146                         } else {
 147                                 if (condLoopContext != null)
 148                                         condLoopContext.complainOnFinalAssignmentsInLoop(scope,
 149                                                         flowInfo);
 150                                 loopingContext.complainOnFinalAssignmentsInLoop(scope,
 151                                                 actionInfo);
 152                                 actionInfo = actionInfo
 153                                                 .mergedWith(loopingContext.initsOnContinue
 154                                                                 .unconditionalInits());
 155                                 // for increments
 156                         }
 157                 }
 158                 if ((continueLabel != null) && (increments != null)) {
 159                         LoopingFlowContext loopContext = new LoopingFlowContext(
 160                                         flowContext, this, null, null, scope);
 161                         int i = 0, count = increments.length;
 162                         while (i < count)
 163                                 actionInfo = increments[i++].analyseCode(scope, loopContext,
 164                                                 actionInfo);
 165                         loopContext.complainOnFinalAssignmentsInLoop(scope, actionInfo);
 166                 }
 167
 168                 // infinite loop
 169                 FlowInfo mergedInfo;
 170                 if (isConditionOptimizedTrue) {
 171                         mergedInitStateIndex = currentScope.methodScope()
 172                                         .recordInitializationStates(
 173                                                         mergedInfo = loopingContext.initsOnBreak);
 174                         return mergedInfo;
 175                 }
 176
 177                 // end of loop: either condition false or break
 178                 mergedInfo = flowInfo.initsWhenFalse().unconditionalInits().mergedWith(
 179                                 loopingContext.initsOnBreak.unconditionalInits());
 180                 if (isConditionOptimizedTrue && continueLabel == null) {
 181                         mergedInfo.setReachMode(FlowInfo.UNREACHABLE);
 182                 }
 183                 mergedInitStateIndex = currentScope.methodScope()
 184                                 .recordInitializationStates(mergedInfo);
 185                 return mergedInfo;
 186         }
 187
 188         /**
 189          * For statement code generation
 190          *
 191          * @param currentScope
 192          *            net.sourceforge.phpdt.internal.compiler.lookup.BlockScope
 193          * @param codeStream
 194          *            net.sourceforge.phpdt.internal.compiler.codegen.CodeStream
 195          */
 196         // public void generateCode(BlockScope currentScope, CodeStream codeStream)
 197         // {
 198         //
 199         // if ((bits & IsReachableMASK) == 0) {
 200         // return;
 201         // }
 202         // int pc = codeStream.position;
 203         //
 204         // // generate the initializations
 205         // if (initializations != null) {
 206         // for (int i = 0, max = initializations.length; i < max; i++) {
 207         // initializations[i].generateCode(scope, codeStream);
 208         // }
 209         // }
 210         //
 211         // // label management
 212         // Label actionLabel = new Label(codeStream);
 213         // Label conditionLabel = new Label(codeStream);
 214         // breakLabel.codeStream = codeStream;
 215         // if (continueLabel != null) {
 216         // continueLabel.codeStream = codeStream;
 217         // }
 218         // // jump over the actionBlock
 219         // if ((condition != null)
 220         // && (condition.constant == NotAConstant)
 221         // && !((action == null || action.isEmptyBlock()) && (increments == null)))
 222         // {
 223         // int jumpPC = codeStream.position;
 224         // codeStream.goto_(conditionLabel);
 225         // codeStream.recordPositionsFrom(jumpPC, condition.sourceStart);
 226         // }
 227         // // generate the loop action
 228         // actionLabel.place();
 229         // if (action != null) {
 230         // // Required to fix 1PR0XVS: LFRE:WINNT - Compiler: variable table for
 231         // method appears incorrect
 232         // if (condIfTrueInitStateIndex != -1) {
 233         // // insert all locals initialized inside the condition into the action
 234         // generated prior to the condition
 235         // codeStream.addDefinitelyAssignedVariables(
 236         // currentScope,
 237         // condIfTrueInitStateIndex);
 238         // }
 239         // action.generateCode(scope, codeStream);
 240         // }
 241         // // continuation point
 242         // if (continueLabel != null) {
 243         // continueLabel.place();
 244         // // generate the increments for next iteration
 245         // if (increments != null) {
 246         // for (int i = 0, max = increments.length; i < max; i++) {
 247         // increments[i].generateCode(scope, codeStream);
 248         // }
 249         // }
 250         // }
 251         //
 252         // // May loose some local variable initializations : affecting the local
 253         // variable attributes
 254         // if (preCondInitStateIndex != -1) {
 255         // codeStream.removeNotDefinitelyAssignedVariables(
 256         // currentScope,
 257         // preCondInitStateIndex);
 258         // }
 259         //
 260         // // generate the condition
 261         // conditionLabel.place();
 262         // if ((condition != null) && (condition.constant == NotAConstant)) {
 263         // condition.generateOptimizedBoolean(scope, codeStream, actionLabel, null,
 264         // true);
 265         // } else {
 266         // if (continueLabel != null) {
 267         // codeStream.goto_(actionLabel);
 268         // }
 269         // }
 270         // breakLabel.place();
 271         //
 272         // // May loose some local variable initializations : affecting the local
 273         // variable attributes
 274         // if (neededScope) {
 275         // codeStream.exitUserScope(scope);
 276         // }
 277         // if (mergedInitStateIndex != -1) {
 278         // codeStream.removeNotDefinitelyAssignedVariables(
 279         // currentScope,
 280         // mergedInitStateIndex);
 281         // }
 282         // codeStream.recordPositionsFrom(pc, this.sourceStart);
 283         // }
 284         public void resetStateForCodeGeneration() {
 285                 if (this.breakLabel != null) {
 286                         this.breakLabel.resetStateForCodeGeneration();
 287                 }
 288                 if (this.continueLabel != null) {
 289                         this.continueLabel.resetStateForCodeGeneration();
 290                 }
 291         }
 292
 293         public StringBuffer printStatement(int tab, StringBuffer output) {
 294
 295                 printIndent(tab, output).append("for ("); //$NON-NLS-1$
 296                 // inits
 297                 if (initializations != null) {
 298                         for (int i = 0; i < initializations.length; i++) {
 299                                 // nice only with expressions
 300                                 if (i > 0)
 301                                         output.append(", "); //$NON-NLS-1$
 302                                 initializations[i].print(0, output);
 303                         }
 304                 }
 305                 output.append("; "); //$NON-NLS-1$
 306                 // cond
 307                 if (condition != null)
 308                         condition.printExpression(0, output);
 309                 output.append("; "); //$NON-NLS-1$
 310                 // updates
 311                 if (increments != null) {
 312                         for (int i = 0; i < increments.length; i++) {
 313                                 if (i > 0)
 314                                         output.append(", "); //$NON-NLS-1$
 315                                 increments[i].print(0, output);
 316                         }
 317                 }
 318                 output.append(") "); //$NON-NLS-1$
 319                 // block
 320                 if (action == null)
 321                         output.append(';');
 322                 else {
 323                         output.append('\n');
 324                         action.printStatement(tab + 1, output); //$NON-NLS-1$
 325                 }
 326                 return output.append(';');
 327         }
 328
 329         public void resolve(BlockScope upperScope) {
 330
 331                 // use the scope that will hold the init declarations
 332                 scope = neededScope ? new BlockScope(upperScope) : upperScope;
 333                 if (initializations != null)
 334                         for (int i = 0, length = initializations.length; i < length; i++)
 335                                 initializations[i].resolve(scope);
 336                 if (condition != null) {
 337                         TypeBinding type = condition.resolveTypeExpecting(scope,
 338                                         BooleanBinding);
 339                         condition.implicitWidening(type, type);
 340                 }
 341                 if (increments != null)
 342                         for (int i = 0, length = increments.length; i < length; i++)
 343                                 increments[i].resolve(scope);
 344                 if (action != null)
 345                         action.resolve(scope);
 346         }
 347
 348         public String toString(int tab) {
 349
 350                 String s = tabString(tab) + "for ("; //$NON-NLS-1$
 351                 if (!neededScope)
 352                         s = s
 353                                         + " //--NO upperscope scope needed\n" + tabString(tab) + "     "; //$NON-NLS-2$ //$NON-NLS-1$
 354                 // inits
 355                 if (initializations != null) {
 356                         for (int i = 0; i < initializations.length; i++) {
 357                                 // nice only with expressions
 358                                 s = s + initializations[i].toString(0);
 359                                 if (i != (initializations.length - 1))
 360                                         s = s + " , "; //$NON-NLS-1$
 361                         }
 362                 }
 363                 ;
 364                 s = s + "; "; //$NON-NLS-1$
 365                 // cond
 366                 if (condition != null)
 367                         s = s + condition.toStringExpression();
 368                 s = s + "; "; //$NON-NLS-1$
 369                 // updates
 370                 if (increments != null) {
 371                         for (int i = 0; i < increments.length; i++) {
 372                                 // nice only with expressions
 373                                 s = s + increments[i].toString(0);
 374                                 if (i != (increments.length - 1))
 375                                         s = s + " , "; //$NON-NLS-1$
 376                         }
 377                 }
 378                 ;
 379                 s = s + ") "; //$NON-NLS-1$
 380                 // block
 381                 if (action == null)
 382                         s = s + "{}"; //$NON-NLS-1$
 383                 else
 384                         s = s + "\n" + action.toString(tab + 1); //$NON-NLS-1$
 385                 return s;
 386         }
 387
 388         public void traverse(ASTVisitor visitor, BlockScope blockScope) {
 389
 390                 if (visitor.visit(this, blockScope)) {
 391                         if (initializations != null) {
 392                                 int initializationsLength = initializations.length;
 393                                 for (int i = 0; i < initializationsLength; i++)
 394                                         initializations[i].traverse(visitor, scope);
 395                         }
 396
 397                         if (condition != null)
 398                                 condition.traverse(visitor, scope);
 399
 400                         if (increments != null) {
 401                                 int incrementsLength = increments.length;
 402                                 for (int i = 0; i < incrementsLength; i++)
 403                                         increments[i].traverse(visitor, scope);
 404                         }
 405
 406                         if (action != null)
 407                                 action.traverse(visitor, scope);
 408                 }
 409                 visitor.endVisit(this, blockScope);
 410         }
 411 }