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Code Issues Wiki Activity

Bug 320277: Cannot view variables of base class in derived class

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This commit is contained in:
Axel Mueller 2011-09-07 10:16:46 -04:00 • committed by Marc Khouzam
parent 8b79206703
commit 84fa9f1b49
5 changed files with 309 additions and 18 deletions
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2
dsf-gdb/org.eclipse.cdt.dsf.gdb/META-INF/MANIFEST.MF
View file

@ -3,7 +3,7 @@ Bundle-ManifestVersion: 2
Bundle-Name: %pluginName
Bundle-Vendor: %providerName
Bundle-SymbolicName: org.eclipse.cdt.dsf.gdb;singleton:=true
Bundle-Version: 4.0.0.qualifier
Bundle-Version: 4.0.1.qualifier
Bundle-Activator: org.eclipse.cdt.dsf.gdb.internal.GdbPlugin
Bundle-Localization: plugin
Require-Bundle: org.eclipse.core.runtime,

2
dsf-gdb/org.eclipse.cdt.dsf.gdb/pom.xml
View file

@ -11,7 +11,7 @@
<relativePath>../../pom.xml</relativePath>
</parent>
<version>4.0.0-SNAPSHOT</version>
<version>4.0.1-SNAPSHOT</version>
<artifactId>org.eclipse.cdt.dsf.gdb</artifactId>
<packaging>eclipse-plugin</packaging>
</project>

177
dsf-gdb/org.eclipse.cdt.dsf.gdb/src/org/eclipse/cdt/dsf/mi/service/MIVariableManager.java
View file

@ -1,5 +1,5 @@
/*******************************************************************************
* Copyright (c) 2008, 2010 Monta Vista and others.
* Copyright (c) 2008, 2011 Monta Vista and others.
* 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
@ -12,6 +12,7 @@
* Ericsson - Major re-factoring to deal with children
* Axel Mueller - Bug 306555 - Add support for cast to type / view as array (IExpressions2)
* Jens Elmenthaler (Verigy) - Added Full GDB pretty-printing support (bug 302121)
* Axel Mueller - Workaround for GDB bug where -var-info-path-expression gives invalid result (Bug 320277)
*******************************************************************************/
package org.eclipse.cdt.dsf.mi.service;
@ -64,6 +65,7 @@ import org.eclipse.cdt.dsf.mi.service.command.output.ExprMetaGetChildCountInfo;
import org.eclipse.cdt.dsf.mi.service.command.output.ExprMetaGetChildrenInfo;
import org.eclipse.cdt.dsf.mi.service.command.output.ExprMetaGetValueInfo;
import org.eclipse.cdt.dsf.mi.service.command.output.ExprMetaGetVarInfo;
import org.eclipse.cdt.dsf.mi.service.command.output.MIDataEvaluateExpressionInfo;
import org.eclipse.cdt.dsf.mi.service.command.output.MIDisplayHint;
import org.eclipse.cdt.dsf.mi.service.command.output.MIDisplayHint.GdbDisplayHint;
import org.eclipse.cdt.dsf.mi.service.command.output.MIInfo;
@ -378,6 +380,15 @@ public class MIVariableManager implements ICommandControl {
private boolean fetchingChildren = false;
/**
* In case of base class variables that are accessed in a derived class
* we cannot trust var-info-path-expression because of a bug in gdb.
* We have to use a workaround and apply it to the complete hierarchy of this varObject.
* Bug 320277
*/
private boolean hasCastToBaseClassWorkaround = false;
public MIVariableObject(VariableObjectId id, MIVariableObject parentObj) {
this(id, parentObj, false);
}
@ -1352,15 +1363,43 @@ public class MIVariableManager implements ICommandControl {
numSubRequests++;
final DataRequestMonitor<String> childPathRm =
new DataRequestMonitor<String>(fSession.getExecutor(), countingRm) {
// Class to keep track of the child's full expression, but also
// if that child had to use the CastToBaseClassWorkaround,
// which needs to be propagated to its own children.
class ChildFullExpressionInfo {
private String childFullExpression;
private boolean childHasCastToBaseClassWorkaround;
public ChildFullExpressionInfo(String path) {
this(path, false);
}
public ChildFullExpressionInfo(String path, boolean hasWorkaround) {
childFullExpression = path == null ? "" : path; //$NON-NLS-1$
childHasCastToBaseClassWorkaround = hasWorkaround;
}
public String getChildPath() { return childFullExpression; }
public boolean getChildHasCastToBaseClassWorkaround() { return childHasCastToBaseClassWorkaround; }
};
final DataRequestMonitor<ChildFullExpressionInfo> childPathRm =
new DataRequestMonitor<ChildFullExpressionInfo>(fSession.getExecutor(), countingRm) {
@Override
protected void handleSuccess() {
final String childPath = getData().getChildPath();
// The child varObj we are about to create should have hasCastToBaseClassWorkaround
// set in two conditions:
// 1- if its parent was set (which is the current varObj)
// 2- if the workaround was used for the child itself, which is part of ChildFullExpressionInfo
final boolean childHasCastToBaseClassWorkaround =
hasCastToBaseClassWorkaround || getData().getChildHasCastToBaseClassWorkaround();
// For children that do not map to a real expression (such as f.public)
// GDB returns an empty string. In this case, we can use another unique
// name, such as the variable name
final boolean fakeChild = (getData().length() == 0);
final String childFullExpression = fakeChild ? child.getVarName() : getData();
final boolean fakeChild = (childPath.length() == 0);
final String childFullExpression = fakeChild ? child.getVarName() : childPath;
// Now try to see if we already have this variable object in our Map
// Since our map names use the expression, and not the GDB given
@ -1395,6 +1434,8 @@ public class MIVariableManager implements ICommandControl {
var = createChild(childId, childFullExpression, indexInParent, child);
}
var.hasCastToBaseClassWorkaround = childHasCastToBaseClassWorkaround;
if (fakeChild) {
addRealChildrenOfFake(var, exprDmc, realChildren,
@ -1425,6 +1466,8 @@ public class MIVariableManager implements ICommandControl {
if (childVar == null) {
childVar = createChild(childId, childFullExpression, indexInParent, child);
childVar.hasCastToBaseClassWorkaround = childHasCastToBaseClassWorkaround;
if (fakeChild) {
addRealChildrenOfFake(childVar, exprDmc, realChildren,
@ -1442,14 +1485,21 @@ public class MIVariableManager implements ICommandControl {
if (isAccessQualifier(child.getExp())) {
// This is just a qualifier level of C++, so we don't need
// to call -var-info-path-expression for real, but just pretend we did.
childPathRm.setData(""); //$NON-NLS-1$
childPathRm.setData(new ChildFullExpressionInfo("")); //$NON-NLS-1$
childPathRm.done();
} else if (isDynamic() || exprInfo.hasDynamicAncestor()) {
// Equivalent to (which can't be implemented): child.hasDynamicAncestor
// The new child has a dynamic ancestor. Such children don't support
// var-info-path-expression. Build the expression ourselves.
childPathRm.setData(buildChildExpression(exprDmc.getExpression(), child.getExp()));
childPathRm.setData(new ChildFullExpressionInfo(buildChildExpression(exprDmc.getExpression(), child.getExp())));
childPathRm.done();
} else if (hasCastToBaseClassWorkaround) {
// We had to use the "CastToBaseClass" workaround in the hierarchy, so we
// know -var-info-path-expression won't work in this case. We have to
// build the expression ourselves again to keep the workaround as part
// of the child's expression.
childPathRm.setData(new ChildFullExpressionInfo(buildChildExpression(exprDmc.getExpression(), child.getExp())));
childPathRm.done();
} else {
// To build the child id, we need the fully qualified expression which we
// can get from -var-info-path-expression starting from GDB 6.7
@ -1459,14 +1509,55 @@ public class MIVariableManager implements ICommandControl {
@Override
protected void handleCompleted() {
if (isSuccess()) {
childPathRm.setData(getData().getFullExpression());
final String expression = getData().getFullExpression();
if (needFixForGDBBug320277() && child.getExp().equals(child.getType()) && !isAccessQualifier(getExpressionInfo().getRelExpr())) {
// Special handling for a derived class that is cast to its base class (see bug 320277)
//
// If the name of a child equals its type then it could be a base class.
// The exception is when the name of the actual variable is identical with the type name (bad coding style :-))
// The only way to tell the difference is to check if the parent is a fake (public/private/protected).
//
// What we could do instead, is make sure we are using C++ (using -var-info-expression). That would
// be safer. However, at this time, there does not seem to be a way to create a variable with the same
// name and type using plain C, so we are safe.
//
// When we know we are dealing with derived class that is cast to its base class
// -var-info-path-expression returns (*(testbase*) this) and in some cases
// this expression will fail when being evaluated in GDB because of a GDB bug.
// Instead, we need (*(struct testbase*) this).
//
// To check if GDB actually has this bug we call -data-evaluate-expression with the return value
// of -var-info-path-expression
IExpressionDMContext exprDmcMIData = fExpressionService.createExpression(exprDmc, expression);
fCommandControl.queueCommand(
fCommandFactory.createMIDataEvaluateExpression(exprDmcMIData),
new DataRequestMonitor<MIDataEvaluateExpressionInfo>(fSession.getExecutor(), childPathRm) {
@Override
protected void handleCompleted() {
if (isSuccess()) {
childPathRm.setData(new ChildFullExpressionInfo(expression));
childPathRm.done();
} else {
// We build the expression ourselves
// We must also indicate that this workaround has been used for this child
// so that we know to keep using it for further descendants.
childPathRm.setData(new ChildFullExpressionInfo(buildDerivedChildExpression(exprDmc.getExpression(), child.getExp()), true));
childPathRm.done();
}
}
});
} else {
childPathRm.setData(new ChildFullExpressionInfo(expression));
childPathRm.done();
}
} else {
// If we don't have var-info-path-expression
// build the expression ourselves
// Note that this does not work well yet
childPathRm.setData(buildChildExpression(exprDmc.getExpression(), child.getExp()));
childPathRm.setData(new ChildFullExpressionInfo(buildChildExpression(exprDmc.getExpression(), child.getExp())));
childPathRm.done();
}
childPathRm.done();
}
});
}
@ -1582,27 +1673,65 @@ public class MIVariableManager implements ICommandControl {
});
}
/**
* Method performing special handling for a derived class that is cast to its base class (see bug 320277).
* The command '-var-info-path-expression' returns (*(testbase*) this) but we need (*(struct testbase*) this).
* Also, in case of a namespace this method adds additional backticks:
* (*(struct 'namespace::testbase'*) this)
*/
private String buildDerivedChildExpression(String parentExp, String childExpr) {
final String CAST_PREFIX = "struct "; //$NON-NLS-1$
// Before doing the cast, let's surround the child expression (base class name) with quotes
// if it contains a :: which indicates a namespace
String childNameForCast = childExpr.contains("::") ? "'" + childExpr + "'" : childExpr; //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
String childFullExpression;
if (isPointer()) {
// casting to pointer base class requires a slightly different format
childFullExpression = "*(" + CAST_PREFIX + childNameForCast + "*)(" + parentExp + ")";//$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
} else {
// casting to base class
childFullExpression = "(" + CAST_PREFIX + childNameForCast + ")" + parentExp;//$NON-NLS-1$ //$NON-NLS-2$
}
return childFullExpression;
}
/**
* This method builds a child expression based on its parent's expression.
* It is a fallback solution for when GDB doesn't support the var-info-path-expression.
*
* Currently, this does not support inherited class such as
* This method does not take care of inherited classes such as
* class foo : bar {
* ...
* }
* because we'll create foo.bar instead of (bar)foo.
* that case is hanlded by buildDerivedChildExpression
*/
private String buildChildExpression(String parentExp, String childExp) {
String childFullExpression;
// If the current varObj is a fake object, we obtain the proper parent
// expression from the parent of the varObj.
if (isAccessQualifier(exprInfo.getRelExpr())) {
parentExp = getParent().getExpression();
}
// For pointers, the child expression is already contained in the parent,
// so we must simply prefix with *
// See Bug219179 for more information.
if (!isDynamic() && !exprInfo.hasDynamicAncestor() && isPointer()) {
return "*("+parentExp+")"; //$NON-NLS-1$//$NON-NLS-2$
childFullExpression = "*("+parentExp+")"; //$NON-NLS-1$//$NON-NLS-2$
} else {
// We must surround the parentExp with parentheses because it
// may be a casted expression.
childFullExpression = "("+parentExp+")." + childExp; //$NON-NLS-1$ //$NON-NLS-2$
}
return parentExp + "." + childExp; //$NON-NLS-1$
// No need for a special case for arrays since we deal with arrays differently
// and don't call this method for them
return childFullExpression;
}
/**
@ -2894,4 +3023,22 @@ public class MIVariableManager implements ICommandControl {
iterator.remove();
}
}
/**
* GDB has a bug which makes -data-evaluate-expression fail when using
* the return value of -var-info-path-expression in the case of derived classes.
* To work around this bug, we don't use -var-info-path-expression for some derived
* classes and all their descendants.
*
* This method had to be kept private for the maintenance release.
*
* See http://sourceware.org/bugzilla/show_bug.cgi?id=11912
* and Bug 320277.
*
* The bug was fixed in GDB 7.3.1.
*
*/
private boolean needFixForGDBBug320277() {
return true;
}
}

2
dsf-gdb/org.eclipse.cdt.tests.dsf.gdb/src/org/eclipse/cdt/tests/dsf/gdb/tests/MIExpressionsTest.java
View file

@ -61,7 +61,7 @@ public class MIExpressionsTest extends BaseTestCase {
private DsfServicesTracker fServicesTracker;
private IExpressions fExpService;
protected IExpressions fExpService;
private int fExprChangedEventCount = 0;

144
dsf-gdb/org.eclipse.cdt.tests.dsf.gdb/src/org/eclipse/cdt/tests/dsf/gdb/tests/tests_7_3/MIExpressionsTest_7_3.java
View file

@ -7,13 +7,29 @@
*
* Contributors:
* Ericsson - Initial Implementation
* Marc Khouzam (Ericsson) - Modify testDeleteChildren() for GDB output
* change (Bug 320277)
*******************************************************************************/
package org.eclipse.cdt.tests.dsf.gdb.tests.tests_7_3;
import static org.junit.Assert.assertTrue;
import org.eclipse.cdt.dsf.concurrent.DataRequestMonitor;
import org.eclipse.cdt.dsf.debug.service.IExpressions.IExpressionDMContext;
import org.eclipse.cdt.dsf.debug.service.IExpressions.IExpressionDMData;
import org.eclipse.cdt.dsf.debug.service.IRunControl.StepType;
import org.eclipse.cdt.dsf.debug.service.IStack.IFrameDMContext;
import org.eclipse.cdt.dsf.mi.service.command.events.MIStoppedEvent;
import org.eclipse.cdt.tests.dsf.gdb.framework.AsyncCompletionWaitor;
import org.eclipse.cdt.tests.dsf.gdb.framework.BackgroundRunner;
import org.eclipse.cdt.tests.dsf.gdb.framework.SyncUtil;
import org.eclipse.cdt.tests.dsf.gdb.launching.TestsPlugin;
import org.eclipse.cdt.tests.dsf.gdb.tests.ITestConstants;
import org.eclipse.cdt.tests.dsf.gdb.tests.MIExpressionsTest;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;
import org.junit.BeforeClass;
import org.junit.Test;
import org.junit.runner.RunWith;
@RunWith(BackgroundRunner.class)
@ -22,4 +38,132 @@ public class MIExpressionsTest_7_3 extends MIExpressionsTest {
public static void beforeClassMethod_7_3() {
setGdbProgramNamesLaunchAttributes(ITestConstants.SUFFIX_GDB_7_3);
}
// Slight change in GDB output to fix a bug, so we must change the test a little
// Bug 320277
@Override
@Test
public void testDeleteChildren() throws Throwable {
SyncUtil.runToLocation("testDeleteChildren");
MIStoppedEvent stoppedEvent = SyncUtil.step(1, StepType.STEP_OVER);
final IFrameDMContext frameDmc = SyncUtil.getStackFrame(stoppedEvent.getDMContext(), 0);
final AsyncCompletionWaitor wait = new AsyncCompletionWaitor();
fExpService.getExecutor().submit(new Runnable() {
public void run() {
// First create the var object and all its children
IExpressionDMContext parentDmc = fExpService.createExpression(frameDmc, "f");
fExpService.getSubExpressions(
parentDmc,
new DataRequestMonitor<IExpressionDMContext[]>(fExpService.getExecutor(), null) {
@Override
protected void handleCompleted() {
if (!isSuccess()) {
wait.waitFinished(getStatus());
} else {
if (getData().length != 5) {
wait.waitFinished(new Status(IStatus.ERROR, TestsPlugin.PLUGIN_ID,
"Failed getting children; expecting 5 got " + getData().length, null));
} else {
String childStr = "((class bar) f)";
if (!getData()[0].getExpression().equals(childStr)) {
wait.waitFinished(new Status(IStatus.ERROR, TestsPlugin.PLUGIN_ID,
"Got child " + getData()[0].getExpression() + " instead of " + childStr, null));
} else {
// Now list the children of the first element
fExpService.getSubExpressions(
getData()[0],
new DataRequestMonitor<IExpressionDMContext[]>(fExpService.getExecutor(), null) {
@Override
protected void handleCompleted() {
if (!isSuccess()) {
wait.waitFinished(getStatus());
} else {
if (getData().length != 2) {
wait.waitFinished(new Status(IStatus.ERROR, TestsPlugin.PLUGIN_ID,
"Failed getting children; expecting 2 got " + getData().length, null));
} else {
String childStr = "((((class bar) f)).d)";
if (!getData()[0].getExpression().equals(childStr)) {
wait.waitFinished(new Status(IStatus.ERROR, TestsPlugin.PLUGIN_ID,
"Got child " + getData()[0].getExpression() + " instead of " + childStr, null));
} else {
wait.setReturnInfo(getData()[0]);
wait.waitFinished();
}
}
}
}
});
}
}
}
}
});
}
});
wait.waitUntilDone(AsyncCompletionWaitor.WAIT_FOREVER);
assertTrue(wait.getMessage(), wait.isOK());
final IExpressionDMContext deletedChildDmc = (IExpressionDMContext)wait.getReturnInfo();
wait.waitReset();
fExpService.getExecutor().submit(new Runnable() {
public void run() {
// Now create more than 1000 expressions to trigger the deletion of the children
// that were created above
for (int i=0; i<1100; i++) {
IExpressionDMContext dmc = fExpService.createExpression(frameDmc, "a[" + i + "]");
wait.increment();
fExpService.getExpressionData(
dmc,
new DataRequestMonitor<IExpressionDMData>(fExpService.getExecutor(), null) {
@Override
protected void handleCompleted() {
if (!isSuccess()) {
wait.waitFinished(getStatus());
} else {
wait.waitFinished();
}
}
});
}
}
});
wait.waitUntilDone(AsyncCompletionWaitor.WAIT_FOREVER);
assertTrue(wait.getMessage(), wait.isOK());
wait.waitReset();
fExpService.getExecutor().submit(new Runnable() {
public void run() {
// Evaluate the expression of a child that we know is deleted to make sure
// the expression service can handle that
fExpService.getExpressionData(
deletedChildDmc,
new DataRequestMonitor<IExpressionDMData>(fExpService.getExecutor(), null) {
@Override
protected void handleCompleted() {
if (!isSuccess()) {
wait.waitFinished(getStatus());
} else {
wait.waitFinished();
}
}
});
}
});
wait.waitUntilDone(AsyncCompletionWaitor.WAIT_FOREVER);
assertTrue(wait.getMessage(), wait.isOK());
wait.waitReset();
}
}