From a63a62bc4fbe55ac8c5b7a4c4dc4398a5f25c58f Mon Sep 17 00:00:00 2001
From: Alena Laskavaia <elaskavaia.cdt@gmail.com>
Date: Sun, 1 May 2011 21:14:42 +0000
Subject: [PATCH] Bug 343767 - [fp] 'No return' warning when return in both if
 and else

---
 .../model/cfg/ControlFlowGraphBuilder.java    | 33 ++++++++++++++++---
 .../internal/checkers/ReturnCheckerTest.java  | 10 ++++++
 2 files changed, 39 insertions(+), 4 deletions(-)

diff --git a/codan/org.eclipse.cdt.codan.core.cxx/src/org/eclipse/cdt/codan/core/cxx/internal/model/cfg/ControlFlowGraphBuilder.java b/codan/org.eclipse.cdt.codan.core.cxx/src/org/eclipse/cdt/codan/core/cxx/internal/model/cfg/ControlFlowGraphBuilder.java
index c5f9bd9d847..22076c92a50 100644
--- a/codan/org.eclipse.cdt.codan.core.cxx/src/org/eclipse/cdt/codan/core/cxx/internal/model/cfg/ControlFlowGraphBuilder.java
+++ b/codan/org.eclipse.cdt.codan.core.cxx/src/org/eclipse/cdt/codan/core/cxx/internal/model/cfg/ControlFlowGraphBuilder.java
@@ -77,14 +77,14 @@ public class ControlFlowGraphBuilder {
 		exits = new ArrayList<IExitNode>();
 		dead = new ArrayList<IBasicBlock>();
 		IBasicBlock last = createSubGraph(start, body);
-		if (!(last instanceof IExitNode)) {
-			returnExit = (CxxExitNode) factory.createExitNode(null);
+		if (!(last instanceof IExitNode) && !deadConnector(last)) {
+			returnExit = factory.createExitNode(null);
 			returnExit.setStartNode(start);
 			addOutgoing(last, returnExit);
 			exits.add(returnExit);
 			if (dead.size() > 0) {
-				for (Iterator iterator = dead.iterator(); iterator.hasNext();) {
-					IBasicBlock ds = (IBasicBlock) iterator.next();
+				for (Iterator<IBasicBlock> iterator = dead.iterator(); iterator.hasNext();) {
+					IBasicBlock ds = iterator.next();
 					IBasicBlock dl = findLast(ds);
 					if (dl != null && dl.getOutgoingSize() == 0 && dl != returnExit) {
 						((AbstractBasicBlock) dl).addOutgoing(returnExit);
@@ -97,6 +97,31 @@ public class ControlFlowGraphBuilder {
 		return graph;
 	}
 
+	/**
+	 * @param last
+	 * @return
+	 */
+	private boolean deadConnector(IBasicBlock conn) {
+		if (conn instanceof IJumpNode || conn instanceof IConnectorNode) {
+			if (conn.getIncomingSize() == 0) {
+				return true;
+			}
+			if (conn instanceof IJumpNode) {
+				IJumpNode jm = (IJumpNode) conn;
+				if (jm.isBackwardArc())
+					return false;
+			}
+			IBasicBlock[] conns = conn.getIncomingNodes();
+			for (int i = 0; i < conns.length; i++) {
+				IBasicBlock bb = conns[i];
+				if (!deadConnector(bb))
+					return false;
+			}
+			return true;
+		}
+		return false;
+	}
+
 	public IBasicBlock findLast(IBasicBlock node) {
 		if (node instanceof IJumpNode)
 			return null;
diff --git a/codan/org.eclipse.cdt.codan.core.test/src/org/eclipse/cdt/codan/core/internal/checkers/ReturnCheckerTest.java b/codan/org.eclipse.cdt.codan.core.test/src/org/eclipse/cdt/codan/core/internal/checkers/ReturnCheckerTest.java
index d9174dd00eb..9169ac64a96 100644
--- a/codan/org.eclipse.cdt.codan.core.test/src/org/eclipse/cdt/codan/core/internal/checkers/ReturnCheckerTest.java
+++ b/codan/org.eclipse.cdt.codan.core.test/src/org/eclipse/cdt/codan/core/internal/checkers/ReturnCheckerTest.java
@@ -245,4 +245,14 @@ public class ReturnCheckerTest extends CheckerTestCase {
 		loadCodeAndRunCpp(getAboveComment());
 		checkNoErrors();
 	}
+	//int bar(int foo)
+	//{
+	//    while(foo) {
+	//        return 0;
+	//    }
+	//}
+	public void testWhile() {
+		loadCodeAndRunCpp(getAboveComment());
+		checkErrorLine(1);
+	}
 }
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