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ProceedVisitor.java

/* *******************************************************************
 * Copyright (c) 2002 Palo Alto Research Center, Incorporated (PARC).
 * All rights reserved. 
 * This program and the accompanying materials are made available 
 * under the terms of the Eclipse Public License v1.0 
 * which accompanies this distribution and is available at 
 * http://www.eclipse.org/legal/epl-v10.html 
 *  
 * Contributors: 
 *     PARC     initial implementation 
 * ******************************************************************/


package org.aspectj.ajdt.internal.compiler.ast;

import org.aspectj.weaver.Advice;
import org.aspectj.org.eclipse.jdt.internal.compiler.ASTVisitor;
import org.aspectj.org.eclipse.jdt.internal.compiler.ast.AbstractMethodDeclaration;
import org.aspectj.org.eclipse.jdt.internal.compiler.ast.Expression;
import org.aspectj.org.eclipse.jdt.internal.compiler.ast.MessageSend;
import org.aspectj.org.eclipse.jdt.internal.compiler.ast.NameReference;
import org.aspectj.org.eclipse.jdt.internal.compiler.ast.SingleNameReference;
import org.aspectj.org.eclipse.jdt.internal.compiler.lookup.Binding;
import org.aspectj.org.eclipse.jdt.internal.compiler.lookup.BlockScope;
import org.aspectj.org.eclipse.jdt.internal.compiler.lookup.ClassScope;
import org.aspectj.org.eclipse.jdt.internal.compiler.lookup.LocalVariableBinding;
import org.aspectj.org.eclipse.jdt.internal.compiler.lookup.MethodBinding;
import org.aspectj.org.eclipse.jdt.internal.compiler.lookup.ReferenceBinding;
import org.aspectj.org.eclipse.jdt.internal.compiler.lookup.TypeBinding;

/**
 * Takes a method that already has the three extra parameters
 * thisJoinPointStaticPart, thisJoinPoint and thisEnclosingJoinPointStaticPart
 */

00036 public class ProceedVisitor extends ASTVisitor {
      boolean needsDynamic = false;
      boolean needsStatic = false;
      boolean needsStaticEnclosing = false;
      boolean hasEffectivelyStaticRef = false;

      LocalVariableBinding thisJoinPointDec;
      LocalVariableBinding thisJoinPointStaticPartDec;
      LocalVariableBinding thisEnclosingJoinPointStaticPartDec;
      
      LocalVariableBinding thisJoinPointDecLocal;
      LocalVariableBinding thisJoinPointStaticPartDecLocal;
      LocalVariableBinding thisEnclosingJoinPointStaticPartDecLocal;

      boolean replaceEffectivelyStaticRefs = false;
      
      AbstractMethodDeclaration method;

      ProceedVisitor(AbstractMethodDeclaration method) {
            this.method = method;
            int index = method.arguments.length - 3;
            
            thisJoinPointStaticPartDecLocal = method.scope.locals[index];
            thisJoinPointStaticPartDec = method.arguments[index++].binding;
            thisJoinPointDecLocal = method.scope.locals[index];
            thisJoinPointDec = method.arguments[index++].binding;
            thisEnclosingJoinPointStaticPartDecLocal = method.scope.locals[index];
            thisEnclosingJoinPointStaticPartDec = method.arguments[index++].binding;
      }

      public void computeJoinPointParams() {
            // walk my body to see what is needed
            method.traverse(this, (ClassScope) null);

            //??? add support for option to disable this optimization
            //System.err.println("check:  "+ hasEffectivelyStaticRef + ", " + needsDynamic);
            if (hasEffectivelyStaticRef && !needsDynamic) {
                  // replace effectively static refs with thisJoinPointStaticPart
                  replaceEffectivelyStaticRefs = true;
                  needsStatic = true;
                  method.traverse(this, (ClassScope) null);
            }
      }

      boolean isRef(NameReference ref, Binding binding) {
            return ref.binding == binding;
      }

      boolean isRef(Expression expr, Binding binding) {
            //System.err.println("isRef: " + expr + ", " + binding);
            return expr != null
                  && expr instanceof NameReference
                  && isRef((NameReference) expr, binding);
      }

      public void endVisit(SingleNameReference ref, BlockScope scope) {
            if (isRef(ref, thisJoinPointDec))
                  needsDynamic = true;
            else if (isRef(ref, thisJoinPointStaticPartDec))
                  needsStatic = true;
            else if (isRef(ref, thisEnclosingJoinPointStaticPartDec))
                  needsStaticEnclosing = true;
      }

      //        public void checkAndFix(ASTObject body) {
      //            this.process(body);
      //            if (needsFakeStatic && !needsDynamic) {
      //                if (!this.getCompiler().getOptions().noMetaJoinPointOptimization) {
      //                    makeFakeStatics = true;
      //                    needsStatic = true;
      //                    this.process(body);
      //                } else {
      //                    needsDynamic = true;
      //                }
      //            }
      //        }

      boolean canTreatAsStatic(String id) {
            return id.equals("toString")
                  || id.equals("toShortString")
                  || id.equals("toLongString")
                  || id.equals("getKind")
                  || id.equals("getSignature")
                  || id.equals("getSourceLocation")
                  || id.equals("getStaticPart");
      }

      //        boolean canTreatAsStatic(VarExpr varExpr) {
      //            ASTObject parent = varExpr.getParent();
      //            if (parent instanceof CallExpr) {
      //                Method calledMethod = ((CallExpr)parent).getMethod();
      //                return canTreatAsStatic(calledMethod);
      //
      //                //??? should add a case here to catch
      //                //??? tjp.getEnclosingExecutionJoinPoint().STATIC_METHOD()
      //            } else if (parent instanceof BinopExpr) {
      //                BinopExpr binop = (BinopExpr)parent;
      //                if (binop.getType().isEquivalent(this.getTypeManager().getStringType())) {
      //                    return true;
      //                } else {
      //                    return false;
      //                }
      //            } else {
      //                return false;
      //            }
      //        }

      boolean inBlockThatCantRun = false;

      public boolean visit(MessageSend call, BlockScope scope) {
            Expression receiver = call.receiver;
            if (isRef(receiver, thisJoinPointDec)) {
                  if (canTreatAsStatic(new String(call.selector))) {
                        if (replaceEffectivelyStaticRefs) {
                              replaceEffectivelyStaticRef(call);
                        } else {
                              //System.err.println("has static reg");
                              hasEffectivelyStaticRef = true;
                              if (call.arguments != null) {
                                    int argumentsLength = call.arguments.length;
                                    for (int i = 0; i < argumentsLength; i++)
                                          call.arguments[i].traverse(this, scope);
                              }
                              return false;
                        }
                  }
            }

            return super.visit(call, scope);
      }

      private void replaceEffectivelyStaticRef(MessageSend call) {
            //System.err.println("replace static ref");
            NameReference receiver = (NameReference) call.receiver;
            receiver.binding = thisJoinPointStaticPartDecLocal; //thisJoinPointStaticPartDec;
            receiver.codegenBinding = thisJoinPointStaticPartDecLocal;

            call.binding.declaringClass =
                  (ReferenceBinding) thisJoinPointStaticPartDec.type;
      }

      public int removeUnusedExtraArguments() {
            int extraArgumentFlags = 0;
            
            this.computeJoinPointParams();
            MethodBinding binding = method.binding;
            
            
            int index = binding.parameters.length - 3;
            if (needsStaticEnclosing) {
                  extraArgumentFlags |= Advice.ThisEnclosingJoinPointStaticPart;
            } else {
                  removeParameter(index+2);
            }
            
            if (needsDynamic) {
                  extraArgumentFlags |= Advice.ThisJoinPoint;
            } else {
                  removeParameter(index+1);
            }
            
            if (needsStatic) {
                  extraArgumentFlags |= Advice.ThisJoinPointStaticPart;
            } else {
                  removeParameter(index+0);
            }
            
            return extraArgumentFlags;
      }

      private void removeParameter(int indexToRemove) {
//          TypeBinding[] parameters = method.binding.parameters;
            method.scope.locals = removeLocalBinding(indexToRemove, method.scope.locals);
            method.binding.parameters = removeParameter(indexToRemove, method.binding.parameters);
      }

      
      private static TypeBinding[] removeParameter(int index, TypeBinding[] bindings) {
            int len = bindings.length;
            TypeBinding[] ret = new TypeBinding[len-1];
            System.arraycopy(bindings, 0, ret, 0, index);
            System.arraycopy(bindings, index+1, ret, index, len-index-1);
            return ret;
      }

      private static LocalVariableBinding[] removeLocalBinding(int index, LocalVariableBinding[] bindings) {
            int len = bindings.length;
            //??? for performance we should do this in-place
            LocalVariableBinding[] ret = new LocalVariableBinding[len-1];
            System.arraycopy(bindings, 0, ret, 0, index);
            System.arraycopy(bindings, index+1, ret, index, len-index-1);
            return ret;
      }


}

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