Performance degradation with lombok

Author: snjeza

org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/parser/Scanner.java

@@ -1846,7 +1846,9 @@ else if (c >= LOW_SURROGATE_MIN_VALUE && c <= LOW_SURROGATE_MAX_VALUE) {
 		}
 	} //-----------------end switch while try--------------------
 	catch (IndexOutOfBoundsException e) {
-		if (this.tokenizeWhiteSpace && (whiteStart != this.currentPosition - 1)) {
+		if (this.currentPosition < 0) {
+			this.currentPosition = this.source.length - 1;
+		} else if (this.tokenizeWhiteSpace && (whiteStart != this.currentPosition - 1)) {
 			// reposition scanner in case we are interested by spaces as tokens
 			this.currentPosition--;
 			this.startPosition = whiteStart;

org.eclipse.jdt.core/dom/org/eclipse/jdt/core/dom/CompilationUnit.java

@@ -751,8 +751,10 @@ public int lastTrailingCommentIndex(ASTNode node) {
 	 * @since 3.0
 	 */
 	void initCommentMapper(Scanner scanner) {
-		this.commentMapper = new DefaultCommentMapper(this.optionalCommentTable);
-		this.commentMapper.initialize(this, scanner);
+		if (this.optionalCommentTable != null && this.optionalCommentTable.length > 0) {
+			this.commentMapper = new DefaultCommentMapper(this.optionalCommentTable);
+			this.commentMapper.initialize(this, scanner);
+		}
 	}
 
 	@Override

org.eclipse.jdt.core/dom/org/eclipse/jdt/core/dom/DefaultCommentMapper.java

@@ -562,13 +562,18 @@ class CommentMapperVisitor extends DefaultASTVisitor {
 		@Override
 		protected boolean visitNode(ASTNode node) {
 
+			// skip generated node - https://github.com/eclipse-jdt/eclipse.jdt.core/issues/4712
+			if (node.getStartPosition() <= 0 && node.getLength() <= 0) {
+				return false;
+			}
 			// Get default previous end
 			ASTNode parent = node.getParent();
 			int previousEnd = parent.getStartPosition();
 
 			// Look for sibling node
  			ASTNode sibling = parent == this.topSiblingParent ? (ASTNode) this.siblings[this.siblingPtr] : null;
-			if (sibling != null) {
+			// skip generated node - https://github.com/eclipse-jdt/eclipse.jdt.core/issues/4712
+			if (sibling != null && sibling.getLength() > 0) {
 				// Found one previous sibling, so compute its trailing comments using current node start position
 				try {
 					previousEnd = storeTrailingComments(sibling, node.getStartPosition(), false, this.parentLineRange[this.siblingPtr]);
@@ -624,7 +629,8 @@ protected void endVisitNode(ASTNode node) {
 
 			// Look if a child node is waiting for trailing comments computing
 			ASTNode sibling = this.topSiblingParent == node ? (ASTNode) this.siblings[this.siblingPtr] : null;
-			if (sibling != null) {
+			// skip generated node - https://github.com/eclipse-jdt/eclipse.jdt.core/issues/4712
+			if (sibling != null && sibling.getLength() > 0) {
 				try {
 					storeTrailingComments(sibling, node.getStartPosition()+node.getLength()-1, true, this.parentLineRange[this.siblingPtr]);
 				} catch (Exception ex) {