1 files changed, 202 insertions, 0 deletions
diff --git a/org.eclipse.cdt.codan.checkers/src/org/eclipse/cdt/codan/internal/checkers/ReturnChecker.java b/org.eclipse.cdt.codan.checkers/src/org/eclipse/cdt/codan/internal/checkers/ReturnChecker.java
new file mode 100644
index 0000000..e88c86d
--- /dev/null
+++ b/org.eclipse.cdt.codan.checkers/src/org/eclipse/cdt/codan/internal/checkers/ReturnChecker.java
@@ -0,0 +1,202 @@
+/*******************************************************************************
+ * Copyright (c) 2009,2010 Alena Laskavaia 
+ * 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:
+ *    Alena Laskavaia  - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.cdt.codan.internal.checkers;
+
+import java.util.Iterator;
+
+import org.eclipse.cdt.codan.core.cxx.model.AbstractAstFunctionChecker;
+import org.eclipse.cdt.codan.core.cxx.model.CxxModelsCache;
+import org.eclipse.cdt.codan.core.model.IProblem;
+import org.eclipse.cdt.codan.core.model.IProblemWorkingCopy;
+import org.eclipse.cdt.codan.core.model.cfg.ICfgData;
+import org.eclipse.cdt.codan.core.model.cfg.IControlFlowGraph;
+import org.eclipse.cdt.codan.core.model.cfg.IExitNode;
+import org.eclipse.cdt.core.dom.ast.ASTVisitor;
+import org.eclipse.cdt.core.dom.ast.DOMException;
+import org.eclipse.cdt.core.dom.ast.IASTDeclSpecifier;
+import org.eclipse.cdt.core.dom.ast.IASTDeclaration;
+import org.eclipse.cdt.core.dom.ast.IASTFunctionDeclarator;
+import org.eclipse.cdt.core.dom.ast.IASTFunctionDefinition;
+import org.eclipse.cdt.core.dom.ast.IASTReturnStatement;
+import org.eclipse.cdt.core.dom.ast.IASTSimpleDeclSpecifier;
+import org.eclipse.cdt.core.dom.ast.IASTStatement;
+import org.eclipse.cdt.core.dom.ast.IBasicType;
+import org.eclipse.cdt.core.dom.ast.IType;
+import org.eclipse.cdt.core.dom.ast.c.ICASTSimpleDeclSpecifier;
+
+/**
+ * The checker suppose to find issue related to mismatched return value/function
+ * declaration<br>
+ * <li>Function declared as returning non-void returns void
+ * <li>Function declared as returning void has non-void return
+ * <li>Function declared as returning non-void has no return (requires control
+ * flow graph)
+ */
+public class ReturnChecker extends AbstractAstFunctionChecker  {
+	private static final String PARAM_IMPLICIT = "implicit"; //$NON-NLS-1$
+	public final String RET_NO_VALUE_ID = "org.eclipse.cdt.codan.checkers.noreturn"; //$NON-NLS-1$
+	public final String RET_ERR_VALUE_ID = "org.eclipse.cdt.codan.checkers.errreturnvalue"; //$NON-NLS-1$
+	public final String RET_NORET_ID = "org.eclipse.cdt.codan.checkers.errnoreturn"; //$NON-NLS-1$
+
+	class ReturnStmpVisitor extends ASTVisitor {
+		private IASTFunctionDefinition func;
+		boolean hasret;
+
+		ReturnStmpVisitor(IASTFunctionDefinition func) {
+			shouldVisitStatements = true;
+			shouldVisitDeclarations = true;
+			this.func = func;
+			this.hasret = false;
+		}
+		public int visit(IASTDeclaration element) {
+			if (element!=func)
+			   return PROCESS_SKIP; // skip inner functions
+			return PROCESS_CONTINUE;
+		}
+		public int visit(IASTStatement stmt) {
+			if (stmt instanceof IASTReturnStatement) {
+				hasret = true;
+				IASTReturnStatement ret = (IASTReturnStatement) stmt;
+				if (!isVoid(func)) {
+					if (checkImplicitReturn(RET_NO_VALUE_ID)
+							|| isExplicitReturn(func)) {
+						if (ret.getReturnValue() == null)
+							reportProblem(RET_NO_VALUE_ID, ret);
+					}
+				} else {
+					if (ret.getReturnValue() != null) {
+						IType type = ret.getReturnValue().getExpressionType();
+						if (isVoid(type)) 
+							return PROCESS_SKIP;
+						reportProblem(RET_ERR_VALUE_ID, ret.getReturnValue());
+					}
+				}
+
+				return PROCESS_SKIP;
+			}
+			return PROCESS_CONTINUE;
+		}
+
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * 
+	 * @see org.eclipse.cdt.codan.core.cxx.model.AbstractAstFunctionChecker#
+	 * processFunction(org.eclipse.cdt.core.dom.ast.IASTFunctionDefinition)
+	 */
+	@Override
+	protected void processFunction(IASTFunctionDefinition func) {
+		ReturnStmpVisitor visitor = new ReturnStmpVisitor(func);
+		func.accept(visitor);
+		if (!visitor.hasret) {
+			// no return at all
+			if (!isVoid(func)
+					&& (checkImplicitReturn(RET_NORET_ID) || isExplicitReturn(func))) {
+				if (endsWithNoExitNode(func))
+					reportProblem(RET_NORET_ID, func.getDeclSpecifier());
+			}
+		}
+	}
+
+	/**
+	 * @param if - problem id
+	 * @return true if need to check inside functions with implicit return
+	 */
+	protected boolean checkImplicitReturn(String id) {
+		final IProblem pt = getProblemById(id, getFile());
+		return (Boolean) getPreference(pt,PARAM_IMPLICIT);
+	}
+
+	/**
+	 * @param func
+	 * @return
+	 */
+	protected boolean endsWithNoExitNode(IASTFunctionDefinition func) {
+		IControlFlowGraph graph = CxxModelsCache.getInstance()
+				.getControlFlowGraph(func);
+		Iterator<IExitNode> exitNodeIterator = graph.getExitNodeIterator();
+		boolean noexitop = false;
+		for (; exitNodeIterator.hasNext();) {
+			IExitNode node = exitNodeIterator.next();
+			if (((ICfgData) node).getData() == null) {
+				// if it real exit node such as return, exit or throw data
+				// will be an ast node, it is null it is fake node added by the
+				// graph builder
+				noexitop = true;
+				break;
+			}
+		}
+		return noexitop;
+	}
+
+	/**
+	 * @param func
+	 * @return
+	 */
+	protected boolean isExplicitReturn(IASTFunctionDefinition func) {
+		return getDeclSpecType(func) != ICASTSimpleDeclSpecifier.t_unspecified;
+	}
+
+	/**
+	 * @param func
+	 * @return
+	 */
+	public boolean isVoid(IASTFunctionDefinition func) {
+		int type = getDeclSpecType(func);
+		if (type == IASTSimpleDeclSpecifier.t_void) {
+			IASTFunctionDeclarator declarator = func.getDeclarator();
+			if (declarator.getPointerOperators().length == 0)
+				return true;
+		}
+		return false;
+	}
+	/**
+	 * check if type if void
+	 * (uses deprecated API for compatibility with 6.0)
+	 * @param type
+	 * @throws DOMException
+	 */
+	@SuppressWarnings("deprecation")
+	public boolean isVoid(IType type) {
+		if (type instanceof IBasicType) {
+			try {
+				if (((IBasicType) type).getType()==IBasicType.t_void)
+					return true;
+			} catch (DOMException e) {
+				return false;
+			}
+		}
+		return false;
+	}
+	/**
+	 * @param func
+	 * @return
+	 */
+	protected int getDeclSpecType(IASTFunctionDefinition func) {
+		IASTDeclSpecifier declSpecifier = func.getDeclSpecifier();
+		int type = -1;
+		if (declSpecifier instanceof IASTSimpleDeclSpecifier) {
+			type = ((IASTSimpleDeclSpecifier) declSpecifier).getType();
+		}
+		return type;
+	}
+
+	/* checker must implement @link ICheckerWithPreferences */
+	public void initPreferences(IProblemWorkingCopy problem) {
+		super.initPreferences(problem);
+		if (problem.getId().equals(RET_NO_VALUE_ID)
+				|| problem.getId().equals(RET_NORET_ID)) {
+			addPreference(problem, PARAM_IMPLICIT,
+					CheckersMessages.ReturnChecker_Param0, Boolean.FALSE);
+		}
+	}
+}