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Code Issues Wiki Activity

Bug 455828 - Don't be over-eager when collecting dead nodes in the

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control flow graph

Change-Id: I54013e31a197c02698e3161f9f52755e4cb6b203
Signed-off-by: Nathan Ridge <zeratul976@hotmail.com>
This commit is contained in:
Nathan Ridge 2015-02-17 02:51:02 -05:00 • committed by Gerrit Code Review @ Eclipse.org
parent bb8cc948c4
commit 80c624f2c3
4 changed files with 67 additions and 18 deletions
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7
codan/org.eclipse.cdt.codan.checkers/src/org/eclipse/cdt/codan/internal/checkers/ReturnChecker.java
View file

@ -194,12 +194,7 @@ public class ReturnChecker extends AbstractAstFunctionChecker {
public Collection<IBasicBlock> getDeadBlocks(IASTFunctionDefinition func) {
Collection<IBasicBlock> result = new LinkedHashSet<IBasicBlock>();
IControlFlowGraph graph = getModelCache().getControlFlowGraph(func);
Iterator<IBasicBlock> unconnectedNodeIterator = graph.getUnconnectedNodeIterator();
for (Iterator<IBasicBlock> iterator = unconnectedNodeIterator; iterator.hasNext();) {
IBasicBlock block = iterator.next();
((ControlFlowGraph) graph).getNodes(block, result);
}
return result;
return ((ControlFlowGraph) graph).getDeadNodes();
}
protected void reportNoRet(IASTFunctionDefinition func, boolean hasRet) {

19
codan/org.eclipse.cdt.codan.core.test/src/org/eclipse/cdt/codan/core/cfg/ControlFlowGraphTest.java
View file

@ -10,7 +10,6 @@
*******************************************************************************/
package org.eclipse.cdt.codan.core.cfg;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
@ -562,8 +561,7 @@ public class ControlFlowGraphTest extends CodanFastCxxAstTestCase {
IExitNode ret = (IExitNode) startNode.getOutgoing();
assertEquals("return 1;", data(ret));
IBranchNode labelB = (IBranchNode) graph.getUnconnectedNodeIterator().next(); // BranchNode: b:
ArrayList<IBasicBlock> res = new ArrayList<>();
graph.getNodes(labelB, res);
Collection<IBasicBlock> res = graph.getDeadNodes();
assertEquals(6, res.size());
IJumpNode gotoA = (IJumpNode) ((IConnectorNode) labelB.getOutgoing()).getOutgoing();
@ -618,6 +616,21 @@ public class ControlFlowGraphTest extends CodanFastCxxAstTestCase {
assertEquals("return 1;", data(trueBranch.getOutgoing()));
}
// int foo(int x) {
// switch (x) {
// case 0:
// return 42;;
// default:
// }
// }
public void test_dead_statement_in_switch() throws Exception {
buildAndCheck(getAboveComment());
IDecisionNode swittch = (IDecisionNode) graph.getStartNode().getOutgoing();
Collection<IBasicBlock> deadNodes = graph.getDeadNodes();
// Make sure the switch statement's merge node has not been marked as dead.
assertFalse(deadNodes.contains(swittch.getMergeNode()));
}
// int main(int a) {
// switch (a) {
// case 1: {

12
codan/org.eclipse.cdt.codan.core.test/src/org/eclipse/cdt/codan/core/internal/checkers/ReturnCheckerTest.java
View file

@ -448,4 +448,16 @@ public class ReturnCheckerTest extends CheckerTestCase {
loadCodeAndRunCpp(getAboveComment());
checkErrorLine(1);
}
// int foo(int x) {
// switch (x) {
// case 0:
// return 42;;
// default:
// }
// }
public void testDoubleSemicolonInSwitchCase_455828() throws Exception {
loadCodeAndRunCpp(getAboveComment());
checkErrorLine(1);
}
}

47
codan/org.eclipse.cdt.codan.core/src/org/eclipse/cdt/codan/internal/core/cfg/ControlFlowGraph.java
View file

@ -125,18 +125,11 @@ public class ControlFlowGraph implements IControlFlowGraph {
public Collection<IBasicBlock> getNodes() {
Collection<IBasicBlock> result = new LinkedHashSet<IBasicBlock>();
getNodes(getStartNode(), result);
for (Iterator<IBasicBlock> iterator = deadNodes.iterator(); iterator.hasNext();) {
IBasicBlock d = iterator.next();
getNodes(d, result);
}
getDeadNodes(result);
return result;
}
/**
* @param d
* @param result
*/
public void getNodes(IBasicBlock start, Collection<IBasicBlock> result) {
private void getNodes(IBasicBlock start, Collection<IBasicBlock> result) {
if (start == null)
return; // huh
if (result.contains(start))
@ -152,4 +145,40 @@ public class ControlFlowGraph implements IControlFlowGraph {
}
}
}
public Collection<IBasicBlock> getDeadNodes() {
Collection<IBasicBlock> result = new LinkedHashSet<IBasicBlock>();
getDeadNodes(result);
return result;
}
private void getDeadNodes(Collection<IBasicBlock> result) {
Collection<IBasicBlock> liveNodes = new LinkedHashSet<IBasicBlock>();
getNodes(getStartNode(), liveNodes);
for (Iterator<IBasicBlock> iterator = deadNodes.iterator(); iterator.hasNext();) {
IBasicBlock d = iterator.next();
getDeadNodes(d, result, liveNodes);
}
}
public void getDeadNodes(IBasicBlock start, Collection<IBasicBlock> result, Collection<IBasicBlock> liveNodes) {
if (start == null)
return; // huh
if (result.contains(start))
return;
if (liveNodes.contains(start))
return; // a live node is by definition not dead
result.add(start);
for (IBasicBlock bb : start.getOutgoingNodes()) {
getDeadNodes(bb, result, liveNodes);
}
if (start instanceof IConnectorNode) {
// Sometimes, a dead connector node can have incoming nodes that are not otherwise reachable
// from unconnected nodes (this happens for a branch node for a dead label).
for (IBasicBlock bb : start.getIncomingNodes()) {
getDeadNodes(bb, result, liveNodes);
}
}
}
}