diff --git a/core/org.eclipse.cdt.core/ChangeLog b/core/org.eclipse.cdt.core/ChangeLog
index 6f4a371fb15..77f43d31938 100644
--- a/core/org.eclipse.cdt.core/ChangeLog
+++ b/core/org.eclipse.cdt.core/ChangeLog
@@ -1,3 +1,8 @@
+2004-04-12 Hoda Amer
+	CModelBuilder and scalability problems: Building the CModel takes a long time
+	when translation unit has lots of children (25,000 children taking ~ 45 sec to build model).
+	Revising Parent.addChild() and TranslationUnit.removeChildren() (now 25,000 children taking ~ 160 ms).
+	
 2004-04-07 David Inglis
 	
 	Fixed event problem 
diff --git a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/CContainer.java b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/CContainer.java
index 945ed1ccae8..8f5eeac0ad9 100644
--- a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/CContainer.java
+++ b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/CContainer.java
@@ -213,9 +213,7 @@ public class CContainer extends Openable implements ICContainer {
 			//e.printStackTrace();
 			throw new CModelException(e);
 		}
-		ICElement[] children = new ICElement[vChildren.size()];
-		vChildren.toArray(children);
-		info.setChildren(children);
+		info.setChildren(vChildren);
 		if (info instanceof CContainerInfo) {
 			((CContainerInfo) info).setNonCResources(null);
 		}
diff --git a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/CElementInfo.java b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/CElementInfo.java
index 24350c87e1c..ef4c15cddaf 100644
--- a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/CElementInfo.java
+++ b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/CElementInfo.java
@@ -6,6 +6,8 @@ package org.eclipse.cdt.internal.core.model;
  */
 
 import java.io.File;
+import java.util.ArrayList;
+import java.util.List;
 
 import org.eclipse.cdt.core.model.ICElement;
 import org.eclipse.core.resources.IResource;
@@ -16,11 +18,6 @@ import org.eclipse.core.resources.IResource;
  */
 class CElementInfo {
 
-	/**
-	 * Shared empty collection used for efficiency.
-	 */
-	static Object[] NO_NON_C_RESOURCES = new Object[] {};
-
 	protected CElement element;
 
 	/**
@@ -28,12 +25,7 @@ class CElementInfo {
 	 * object. This is an empty array if this element has
 	 * no children.
 	 */
-	protected ICElement[] fChildren;
-
-	/**
-	 * Shared empty collection used for efficiency.
-	 */
-	protected static ICElement[] fgEmptyChildren = new ICElement[]{};
+	protected List fChildren;
 
 	/**
 	 * Is the structure of this element known
@@ -45,7 +37,7 @@ class CElementInfo {
 
 	protected CElementInfo(CElement element) {
 		this.element = element;
-		fChildren = fgEmptyChildren;
+		fChildren = new ArrayList();
 	}
 
 	protected CElement getElement() {
@@ -53,41 +45,21 @@ class CElementInfo {
 	}
 
 	protected void addChild(ICElement child) {
-		if (fChildren == fgEmptyChildren) {
-			setChildren(new ICElement[] {child});
-		} else {
-			if (!includesChild(child)) {
-				setChildren(growAndAddToArray(fChildren, child));
-			}
-		}
+		fChildren.add(child);
 	}
 
 	protected ICElement[] getChildren() {
-		return fChildren;
+		ICElement[] array= new ICElement[fChildren.size()];		
+		return (ICElement[]) fChildren.toArray( array );
 	}
 
-	/**
-	 * Adds the new element to a new array that contains all of the elements of the old array.
-	 * Returns the new array.
-	 */
-	protected ICElement[] growAndAddToArray(ICElement[] array, ICElement addition) {
-		ICElement[] old = array;
-		array = new ICElement[old.length + 1];
-		System.arraycopy(old, 0, array, 0, old.length);
-		array[old.length] = addition;
-		return array;
-	}
 
 	/**
 	 * Returns <code>true</code> if this child is in my children collection
 	 */
-	protected boolean includesChild(ICElement child) {
-	
-		for (int i= 0; i < fChildren.length; i++) {
-			if (fChildren[i].equals(child)) {
-				return true;
-			}
-		}
+	protected boolean includesChild(ICElement child) {	
+		if(fChildren.contains(child))
+			return true;
 		return false;
 	}
 
@@ -98,42 +70,20 @@ class CElementInfo {
 		return fIsStructureKnown;
 	}
 
-	/**
-	 * Returns an array with all the same elements as the specified array except for
-	 * the element to remove. Assumes that the deletion is contained in the array.
-	 */
-	protected ICElement[] removeAndShrinkArray(ICElement[] array, ICElement deletion) {
-		ICElement[] old = array;
-		array = new ICElement[old.length - 1];
-		int j = 0;
-		for (int i = 0; i < old.length; i++) {
-			if (!old[i].equals(deletion)) {
-				array[j] = old[i];
-			} else {
-				System.arraycopy(old, i + 1, array, j, old.length - (i + 1));
-				return array;
-			}
-			j++;
-		}
-		return array;
-	}
-
 	protected void removeChild(ICElement child) {
-		if (includesChild(child)) {
-			setChildren(removeAndShrinkArray(fChildren, child));
-		}
+		fChildren.remove(child);
 	}
 
 	protected void removeChildren () {
-		fChildren = fgEmptyChildren;
+		fChildren.clear();
 	}
 
-	protected void setChildren(ICElement[] children) {
-		fChildren = children;
+	protected void setChildren(List children) {
+		fChildren.addAll(children);
 	}
 
 	protected boolean hasChildren() {
-		return fChildren.length > 0;
+		return fChildren.size() > 0;
 	}
 
 	protected void setChanged() {
diff --git a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/CModelBuilder.java b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/CModelBuilder.java
index 8fc5e0c150d..a1bb176662e 100644
--- a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/CModelBuilder.java
+++ b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/CModelBuilder.java
@@ -70,7 +70,7 @@ public class CModelBuilder {
 	private IASTCompilationUnit compilationUnit;
 	// indicator if the unit has parse errors
 	private boolean hasNoErrors = false;
-		
+	
 	public CModelBuilder(org.eclipse.cdt.internal.core.model.TranslationUnit tu) {
 		this.translationUnit = tu ;
 		this.newElements = new HashMap();
@@ -150,6 +150,7 @@ public class CModelBuilder {
 	
 
 	public Map parse(boolean quickParseMode) throws Exception {
+		long startTime = System.currentTimeMillis();
 		try
 		{
 			compilationUnit = parse( translationUnit, quickParseMode, true);		
@@ -160,7 +161,9 @@ public class CModelBuilder {
 			Util.debugLog( "Parse Exception in CModelBuilder", IDebugLogConstants.MODEL );  //$NON-NLS-1$
 			//e.printStackTrace();
 		}
-		long startTime = System.currentTimeMillis();
+		Util.debugLog("CModel parsing: "+ ( System.currentTimeMillis() - startTime ) + "ms", IDebugLogConstants.MODEL); //$NON-NLS-1$ //$NON-NLS-2$
+		
+		startTime = System.currentTimeMillis();
 		try
 		{ 
 			generateModelElements();
@@ -170,13 +173,12 @@ public class CModelBuilder {
 		catch( NullPointerException npe )
 		{
 			Util.debugLog( "NullPointer exception in CModelBuilder", IDebugLogConstants.MODEL);  //$NON-NLS-1$
-			//npe.printStackTrace();
 		}
 				 
 		// For the debuglog to take place, you have to call
 		// Util.setDebugging(true);
 		// Or set debug to true in the core plugin preference 
-		Util.debugLog("CModel build: "+ ( System.currentTimeMillis() - startTime ) + "ms", IDebugLogConstants.MODEL); //$NON-NLS-1$ //$NON-NLS-2$
+		Util.debugLog("CModel building: "+ ( System.currentTimeMillis() - startTime ) + "ms", IDebugLogConstants.MODEL); //$NON-NLS-1$ //$NON-NLS-2$
 		return this.newElements;
 		
 	}	
@@ -344,6 +346,7 @@ public class CModelBuilder {
 		element.setLines( macro.getStartingLine(), macro.getEndingLine() );
 		this.newElements.put(element, element.getElementInfo());
 		return element;
+		
 	}
 	
 	private Namespace createNamespace(Parent parent, IASTNamespaceDefinition nsDef){
@@ -656,4 +659,10 @@ public class CModelBuilder {
 		return element;
 	}
 
+	/**
+	 * @return Returns the newElements.
+	 */
+	public Map getNewElements() {
+		return newElements;
+	}
 }
diff --git a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/CModelInfo.java b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/CModelInfo.java
index 5fa93c3c9a9..39f22c9e27d 100644
--- a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/CModelInfo.java
+++ b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/CModelInfo.java
@@ -41,7 +41,7 @@ public class CModelInfo extends OpenableInfo {
 			}
 		}
 		if (index == 0) {
-			return NO_NON_C_RESOURCES;
+			return new Object[] {}; // NO_NON_C_RESOURCES
 		}
 		if (index < length) {
 			System.arraycopy(nonCProjects, 0, nonCProjects = new Object[index], 0, index);
diff --git a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/CModelStatus.java b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/CModelStatus.java
index e6939dd3e38..659cd168170 100644
--- a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/CModelStatus.java
+++ b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/CModelStatus.java
@@ -4,6 +4,9 @@ package org.eclipse.cdt.internal.core.model;
  * (c) Copyright QNX Software Systems Ltd. 2002.
  * All Rights Reserved.
  */
+import java.util.ArrayList;
+import java.util.List;
+
 import org.eclipse.cdt.core.CCorePlugin;
 import org.eclipse.cdt.core.model.ICElement;
 import org.eclipse.cdt.core.model.ICModelStatus;
@@ -24,7 +27,7 @@ public class CModelStatus extends Status implements ICModelStatus, ICModelStatus
 	 * The elements related to the failure, or <code>null</code>
 	 * if no elements are involved.
 	 */
-	protected ICElement[] fElements = new ICElement[0];
+	protected List fElements = new ArrayList();
 	/**
 	 * The path related to the failure, or <code>null</code>
 	 * if no path is involved.
@@ -59,7 +62,7 @@ public class CModelStatus extends Status implements ICModelStatus, ICModelStatus
 	 */
 	public CModelStatus(int code) {
 		super(ERROR, CCorePlugin.PLUGIN_ID, code, "CModelStatus", null); //$NON-NLS-1$
-		fElements= CElementInfo.fgEmptyChildren;
+		fElements.clear();
 	}
 
 	/**
@@ -68,7 +71,8 @@ public class CModelStatus extends Status implements ICModelStatus, ICModelStatus
 	 */
 	public CModelStatus(int code, ICElement[] elements) {
 		super(ERROR, CCorePlugin.PLUGIN_ID, code, "CModelStatus", null); //$NON-NLS-1$
-		fElements= elements;
+		for(int i=0; i<elements.length; ++i)
+			fElements.add(elements[i]);
 		fPath= null;
 	}
 
@@ -81,7 +85,7 @@ public class CModelStatus extends Status implements ICModelStatus, ICModelStatus
 
 	public CModelStatus(int severity, int code, String string) {
 		super(severity, CCorePlugin.PLUGIN_ID, code, "CModelStatus", null); //$NON-NLS-1$
-		fElements= CElementInfo.fgEmptyChildren;
+		fElements.clear();
 		fPath= null;
 		fString = string;
 	}	
@@ -91,7 +95,7 @@ public class CModelStatus extends Status implements ICModelStatus, ICModelStatus
 	 */
 	public CModelStatus(int code, Throwable throwable) {
 		super(ERROR, CCorePlugin.PLUGIN_ID, code, "CModelStatus", throwable); //$NON-NLS-1$
-		fElements= CElementInfo.fgEmptyChildren;
+		fElements.clear();
 	}
 
 	/**
@@ -99,7 +103,7 @@ public class CModelStatus extends Status implements ICModelStatus, ICModelStatus
 	 */
 	public CModelStatus(int code, IPath path) {
 		super(ERROR, CCorePlugin.PLUGIN_ID, code, "CModelStatus", null); //$NON-NLS-1$
-		fElements= CElementInfo.fgEmptyChildren;
+		fElements.clear();
 		fPath= path;
 	}
 
@@ -150,7 +154,7 @@ public class CModelStatus extends Status implements ICModelStatus, ICModelStatus
 	 * @see ICModelStatus
 	 */
 	public ICElement[] getElements() {
-		return fElements;
+		return (ICElement[])fElements.toArray(new ICElement[fElements.size()]);
 	}
 
 	/**
diff --git a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/CProject.java b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/CProject.java
index e9c574dfa6e..2559b5944de 100644
--- a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/CProject.java
+++ b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/CProject.java
@@ -10,6 +10,7 @@ import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
+import java.util.List;
 import java.util.Map;
 
 import org.eclipse.cdt.core.CCProjectNature;
@@ -425,8 +426,6 @@ public class CProject extends Openable implements ICProject {
 		System.arraycopy(children, 0, roots, 0, length);
 			
 		return roots;
-
-		//return computeSourceRoots();
 	}
 
 	/**
@@ -441,10 +440,10 @@ public class CProject extends Openable implements ICProject {
 			if (pinfo.sourceRoots != null) {
 				roots = pinfo.sourceRoots;
 			} else {
-				roots = pinfo.sourceRoots = computeSourceRoots();				
+				roots = pinfo.sourceRoots = (ISourceRoot[])computeSourceRoots().toArray(new ISourceRoot[computeSourceRoots().size()]);				
 			}
 		} else {
-			roots = computeSourceRoots();
+			roots = (ISourceRoot[])computeSourceRoots().toArray(new ISourceRoot[computeSourceRoots().size()]);
 		}
 		return roots;
 	}
@@ -535,7 +534,7 @@ public class CProject extends Openable implements ICProject {
 		return validInfo;
 	}
 
-	protected ISourceRoot[] computeSourceRoots() throws CModelException {
+	protected List computeSourceRoots() throws CModelException {
 		IPathEntry[] entries = getResolvedPathEntries();
 		ArrayList list = new ArrayList(entries.length);
 		for (int i = 0; i < entries.length; i++) {
@@ -547,9 +546,7 @@ public class CProject extends Openable implements ICProject {
 				}
 			}
 		}
-		ISourceRoot[] roots = new ISourceRoot[list.size()];
-		list.toArray(roots);
-		return roots;
+		return list;
 	}
 
 	protected boolean computeSourceRoots(OpenableInfo info, IResource res) throws CModelException {
diff --git a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/IncludeReference.java b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/IncludeReference.java
index cf4eb99e71a..f1414246f3c 100644
--- a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/IncludeReference.java
+++ b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/IncludeReference.java
@@ -114,9 +114,7 @@ public class IncludeReference extends Openable implements IIncludeReference {
 					}
 				}
 			}
-			ICElement[] children = new ICElement[vChildren.size()];
-			vChildren.toArray(children);
-			info.setChildren(children);
+			info.setChildren(vChildren);
 			return true;
 	}
 
diff --git a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/SourceRoot.java b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/SourceRoot.java
index 6fd3d8debe3..f12fcdf4e11 100644
--- a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/SourceRoot.java
+++ b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/SourceRoot.java
@@ -78,9 +78,7 @@ public class SourceRoot extends CContainer implements ISourceRoot {
 				//e.printStackTrace();
 				throw new CModelException(e);
 			}
-			ICElement[] children = new ICElement[vChildren.size()];
-			vChildren.toArray(children);
-			info.setChildren(children);
+			info.setChildren(vChildren);
 			if (info instanceof CContainerInfo) {
 				((CContainerInfo) info).setNonCResources(null);
 			}
diff --git a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/TranslationUnit.java b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/TranslationUnit.java
index 660496b5bce..2e4f8f8b761 100644
--- a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/TranslationUnit.java
+++ b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/TranslationUnit.java
@@ -11,20 +11,24 @@ import java.util.Iterator;
 import java.util.Map;
 
 import org.eclipse.cdt.core.CCorePlugin;
-import org.eclipse.cdt.core.model.*;
 import org.eclipse.cdt.core.model.CModelException;
 import org.eclipse.cdt.core.model.IBuffer;
 import org.eclipse.cdt.core.model.ICElement;
 import org.eclipse.cdt.core.model.IInclude;
 import org.eclipse.cdt.core.model.IParent;
+import org.eclipse.cdt.core.model.ISourceManipulation;
 import org.eclipse.cdt.core.model.ISourceRange;
 import org.eclipse.cdt.core.model.ISourceReference;
 import org.eclipse.cdt.core.model.ITranslationUnit;
 import org.eclipse.cdt.core.model.IUsing;
+import org.eclipse.cdt.core.model.IWorkingCopy;
 import org.eclipse.core.resources.IFile;
 import org.eclipse.core.resources.IResource;
 import org.eclipse.core.runtime.IPath;
 import org.eclipse.core.runtime.IProgressMonitor;
+import org.eclipse.core.runtime.IStatus;
+import org.eclipse.core.runtime.Status;
+import org.eclipse.core.runtime.jobs.Job;
 
 /**
  * @see ITranslationUnit
@@ -473,19 +477,28 @@ public class TranslationUnit extends Openable implements ITranslationUnit {
 	 * Parse the buffer contents of this element.
 	 */
 	public Map parse(){
+		removeChildren(this);
+		final CModelBuilder modelBuilder = new CModelBuilder(this);
+		final boolean quickParseMode = ! (CCorePlugin.getDefault().useStructuralParseMode());
 		try {
-				removeChildren();
-				CModelBuilder modelBuilder = new CModelBuilder(this);
-				
-				boolean quickParseMode = ! (CCorePlugin.getDefault().useStructuralParseMode());
-				return modelBuilder.parse(quickParseMode);
+			return modelBuilder.parse(quickParseMode);
 		} catch (Exception e) {
-			// FIXME: use the debug log for this exception.
-			//System.out.println(e);
+			// use the debug log for this exception.
+			Util.debugLog( "Exception in CModelBuilder", IDebugLogConstants.MODEL);  //$NON-NLS-1$
 			return null;
-		}
+		}							
 	}
 	
+	public void removeChildren(ICElement element){
+		if (element instanceof Parent){
+			Parent parent = (Parent) element;
+			ICElement[] children = parent.getChildren();
+			for(int i =0; i< children.length; ++i){
+				removeChildren(children[i]);
+			}
+			parent.removeChildren();
+		}
+	}
 
 	
 }
diff --git a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/TranslationUnitInfo.java b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/TranslationUnitInfo.java
index e566162bb1f..a4d7024963f 100644
--- a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/TranslationUnitInfo.java
+++ b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/TranslationUnitInfo.java
@@ -5,7 +5,6 @@ package org.eclipse.cdt.internal.core.model;
  * All Rights Reserved.
  */
 
-import org.eclipse.cdt.core.model.ICElement;
 import org.eclipse.cdt.core.model.ISourceRange;
 import org.eclipse.core.runtime.IPath;
 
@@ -24,45 +23,6 @@ class TranslationUnitInfo extends OpenableInfo {
 		super(element);
 	}
 
-	protected boolean hasChildren() {
-		return true;
-	}
-
-	protected ICElement [] getChildren() {
-		// CHECKPOINT: replacing the parsing done here before
-		return fChildren;		
-	}
-/*
-	protected Map parse(InputStream in, boolean requiresLineNumbers) {
-		try {
-			removeChildren();
-			if (CCorePlugin.getDefault().useNewParser()) {
-				// new parser
-				CModelBuilder modelBuilder = new CModelBuilder((TranslationUnit)getElement());
-				return (modelBuilder.parse(requiresLineNumbers));
-
-			} else {
-				// cdt 1.0 parser
-				ModelBuilder modelBuilder= new ModelBuilder((TranslationUnit)getElement());
-				CStructurizer.getCStructurizer().parse(modelBuilder, in);
-				return null;
-			}	
-		} catch (Exception e) {
-			System.out.println(e);
-			return null;
-		}
-	}
-
-	protected Map parse(String buf, boolean requiresLineNumbers) {
-		// CHECKPOINT: Parsing a string using the StringBufferInputStream
-		// FIXME: quick fix for the IBinary which uses fake translationUnit
-		if (buf != null) {
-			StringBufferInputStream in = new StringBufferInputStream (buf);
-			return (parse (in, requiresLineNumbers));
-		}
-		return null;
-	}
-*/
 	/* Overide the SourceManipulation for the range.  */
 	protected ISourceRange getSourceRange() {
 		IPath location = ((TranslationUnit)getElement()).getLocation();