Bug 298455: Stack overflow with deeply nested else if statements.

3 files changed, 120 insertions, 40 deletions

diff --git a/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/AST2Tests.java b/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/AST2Tests.java
index e8c9b3218f2..c01a6ee36f4 100644
--- a/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/AST2Tests.java
+++ b/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/AST2Tests.java
@@ -7221,4 +7221,18 @@ public class AST2Tests extends AST2BaseTest {
 			IASTTranslationUnit tu = parseAndCheckBindings(code, lang);
 	    }
 	}
+	
+	public void testDeepElseif_298455() throws Exception {
+		sValidateCopy= false;
+		StringBuilder buf= new StringBuilder("void f() {if (0) {}");
+		for (int i = 0; i < 75000; i++) {
+			buf.append("else if (0) {}");
+		}
+		buf.append("}");
+		String code= buf.toString();
+	    for(ParserLanguage lang : ParserLanguage.values()) {
+			IASTTranslationUnit tu = parseAndCheckBindings(code, lang);
+	    }
+	}
+
 }
diff --git a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/c/CASTIfStatement.java b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/c/CASTIfStatement.java
index ba8ccb9aaa2..2a2a7fd56e5 100644
--- a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/c/CASTIfStatement.java
+++ b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/c/CASTIfStatement.java
@@ -92,26 +92,58 @@ public class CASTIfStatement extends ASTNode implements IASTIfStatement, IASTAmb
 		}
     }
 
-    @Override
-	public boolean accept( ASTVisitor action ){
-        if( action.shouldVisitStatements ){
-		    switch( action.visit( this ) ){
-	            case ASTVisitor.PROCESS_ABORT : return false;
-	            case ASTVisitor.PROCESS_SKIP  : return true;
-	            default : break;
-	        }
-		}
-        if( condition != null ) if( !condition.accept( action ) ) return false;
-        if( thenClause != null ) if( !thenClause.accept( action ) ) return false;
-        if( elseClause != null ) if( !elseClause.accept( action ) ) return false;
-
-        if( action.shouldVisitStatements ){
-		    switch( action.leave( this ) ){
-	            case ASTVisitor.PROCESS_ABORT : return false;
-	            case ASTVisitor.PROCESS_SKIP  : return true;
-	            default : break;
-	        }
+	private static class N {
+		final IASTIfStatement fIfStatement;
+		N fNext;
+
+		N(IASTIfStatement stmt) {
+			fIfStatement = stmt;
 		}
+	}
+
+    @Override
+	public boolean accept(ASTVisitor action) {
+    	N stack= null;
+    	IASTIfStatement stmt= this;
+    	loop: for(;;) {
+    		if (action.shouldVisitStatements) {
+    			switch (action.visit(this)) {
+    			case ASTVisitor.PROCESS_ABORT: 	return false;
+    			case ASTVisitor.PROCESS_SKIP: 	
+    				stmt= null;
+    				break loop;
+    			default: break;
+    			}
+    		}
+    		IASTNode child = stmt.getConditionExpression();
+    		if (child != null && !child.accept(action))
+    			return false;
+    		child= stmt.getThenClause();
+    		if (child != null && !child.accept(action))
+    			return false;
+    		child= stmt.getElseClause();
+    		if (child instanceof IASTIfStatement) {
+    			if (action.shouldVisitStatements) {
+    				N n= new N(stmt);
+    				n.fNext= stack;
+    				stack= n;
+    			}
+    			stmt= (IASTIfStatement) child;
+    		} else {
+    			if (child != null && !child.accept(action))
+    				return false;
+    			break loop;
+    		}
+    	}
+    	if (action.shouldVisitStatements) {
+    		if (stmt != null && action.leave(stmt) == ASTVisitor.PROCESS_ABORT)
+    			return false;
+    		while (stack != null) {
+    			if (action.leave(stack.fIfStatement) == ASTVisitor.PROCESS_ABORT)
+    				return false;
+    			stack= stack.fNext;
+    		}
+    	}
         return true;
     }
 
diff --git a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/CPPASTIfStatement.java b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/CPPASTIfStatement.java
index 63f49f3b2a9..c850b0641da 100644
--- a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/CPPASTIfStatement.java
+++ b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/CPPASTIfStatement.java
@@ -13,6 +13,7 @@ package org.eclipse.cdt.internal.core.dom.parser.cpp;
 import org.eclipse.cdt.core.dom.ast.ASTVisitor;
 import org.eclipse.cdt.core.dom.ast.IASTDeclaration;
 import org.eclipse.cdt.core.dom.ast.IASTExpression;
+import org.eclipse.cdt.core.dom.ast.IASTIfStatement;
 import org.eclipse.cdt.core.dom.ast.IASTNode;
 import org.eclipse.cdt.core.dom.ast.IASTStatement;
 import org.eclipse.cdt.core.dom.ast.IScope;
@@ -98,28 +99,61 @@ public class CPPASTIfStatement extends ASTNode implements ICPPASTIfStatement, IA
 		} 
     }
 
-    @Override
-	public boolean accept( ASTVisitor action ){
-        if( action.shouldVisitStatements ){
-		    switch( action.visit( this ) ){
-	            case ASTVisitor.PROCESS_ABORT : return false;
-	            case ASTVisitor.PROCESS_SKIP  : return true;
-	            default : break;
-	        }
-		}
-        if( condition != null ) if( !condition.accept( action ) ) return false;
-        if( condDecl != null )  if( !condDecl.accept( action )) return false;
-        if( thenClause != null ) if( !thenClause.accept( action ) ) return false;
-        if( elseClause != null ) if( !elseClause.accept( action ) ) return false;
-        
-        if( action.shouldVisitStatements ){
-		    switch( action.leave( this ) ){
-	            case ASTVisitor.PROCESS_ABORT : return false;
-	            case ASTVisitor.PROCESS_SKIP  : return true;
-	            default : break;
-	        }
+	private static class N {
+		final IASTIfStatement fIfStatement;
+		N fNext;
+
+		N(IASTIfStatement stmt) {
+			fIfStatement = stmt;
 		}
-        
+	}
+
+    @Override
+	public boolean accept(ASTVisitor action) {
+    	N stack= null;
+    	ICPPASTIfStatement stmt= this;
+    	loop: for(;;) {
+    		if (action.shouldVisitStatements) {
+    			switch (action.visit(this)) {
+    			case ASTVisitor.PROCESS_ABORT: 	return false;
+    			case ASTVisitor.PROCESS_SKIP: 	
+    				stmt= null;
+    				break loop;
+    			default: break;
+    			}
+    		}
+    		IASTNode child = stmt.getConditionExpression();
+    		if (child != null && !child.accept(action))
+    			return false;
+    		child= stmt.getConditionDeclaration();
+    		if (child != null && !child.accept(action))
+    			return false;
+    		child= stmt.getThenClause();
+    		if (child != null && !child.accept(action))
+    			return false;
+    		child= stmt.getElseClause();
+    		if (child instanceof ICPPASTIfStatement) {
+    			if (action.shouldVisitStatements) {
+    				N n= new N(stmt);
+    				n.fNext= stack;
+    				stack= n;
+    			}
+    			stmt= (ICPPASTIfStatement) child;
+    		} else {
+    			if (child != null && !child.accept(action))
+    				return false;
+    			break loop;
+    		}
+    	}
+    	if (action.shouldVisitStatements) {
+    		if (stmt != null && action.leave(stmt) == ASTVisitor.PROCESS_ABORT)
+    			return false;
+    		while (stack != null) {
+    			if (action.leave(stack.fIfStatement) == ASTVisitor.PROCESS_ABORT)
+    				return false;
+    			stack= stack.fNext;
+    		}
+    	}
         return true;
     }