debugger: show return value of last function call in Locals and Watchers view

Works only with gdb/Python so far.

src/plugins/debugger/debuggermanager.cpp

@@ -297,14 +297,15 @@ struct DebuggerManagerPrivate
     DebuggerManagerActions m_actions;
 
     QWidget *m_breakWindow;
+    QWidget *m_returnWindow;
     QWidget *m_localsWindow;
+    QWidget *m_watchersWindow;
     QWidget *m_registerWindow;
     QWidget *m_modulesWindow;
     QWidget *m_snapshotWindow;
     SourceFilesWindow *m_sourceFilesWindow;
     QWidget *m_stackWindow;
     QWidget *m_threadsWindow;
-    QWidget *m_watchersWindow;
     DebuggerOutputWindow *m_outputWindow;
 
     bool m_busy;
@@ -401,6 +402,8 @@ void DebuggerManager::init()
     d->m_sourceFilesWindow->setObjectName(QLatin1String("CppDebugSources"));
     d->m_threadsWindow = new ThreadsWindow;
     d->m_threadsWindow->setObjectName(QLatin1String("CppDebugThreads"));
+    d->m_returnWindow = new WatchWindow(WatchWindow::ReturnType, this);
+    d->m_returnWindow->setObjectName(QLatin1String("CppDebugReturn"));
     d->m_localsWindow = new WatchWindow(WatchWindow::LocalsType, this);
     d->m_localsWindow->setObjectName(QLatin1String("CppDebugLocals"));
     d->m_watchersWindow = new WatchWindow(WatchWindow::WatchersType, this);
@@ -484,8 +487,13 @@ void DebuggerManager::init()
     d->m_registerHandler = new RegisterHandler;
     registerView->setModel(d->m_registerHandler->model());
 
-    // Locals
+
+    // Return Value
     d->m_watchHandler = new WatchHandler(this);
+    QTreeView *returnView = qobject_cast<QTreeView *>(d->m_returnWindow);
+    returnView->setModel(d->m_watchHandler->model(ReturnWatch));
+
+    // Locals
     QTreeView *localsView = qobject_cast<QTreeView *>(d->m_localsWindow);
     localsView->setModel(d->m_watchHandler->model(LocalsWatch));
 
@@ -633,6 +641,7 @@ void DebuggerManager::init()
     localsAndWatchers->setObjectName(QLatin1String("CppDebugLocalsAndWatchers"));
     localsAndWatchers->setWindowTitle(d->m_localsWindow->windowTitle());
     localsAndWatchers->addWidget(d->m_localsWindow);
+    localsAndWatchers->addWidget(d->m_returnWindow);
     localsAndWatchers->addWidget(d->m_watchersWindow);
     //localsAndWatchers->addWidget(d->m_tooltipWindow);
     localsAndWatchers->setStretchFactor(0, 3);
@@ -1365,6 +1374,7 @@ void DebuggerManager::setBusyCursor(bool busy)
 
     QCursor cursor(busy ? Qt::BusyCursor : Qt::ArrowCursor);
     d->m_breakWindow->setCursor(cursor);
+    d->m_returnWindow->setCursor(cursor);
     d->m_localsWindow->setCursor(cursor);
     d->m_modulesWindow->setCursor(cursor);
     d->m_outputWindow->setCursor(cursor);
@@ -1947,6 +1957,7 @@ static void changeFontSize(QWidget *widget, int size)
 void DebuggerManager::fontSettingsChanged(const TextEditor::FontSettings &settings)
 {
     int size = settings.fontZoom() * settings.fontSize() / 100;
+    changeFontSize(d->m_returnWindow, size);
     changeFontSize(d->m_localsWindow, size);
     changeFontSize(d->m_watchersWindow, size);
     changeFontSize(d->m_breakWindow, size);
@@ -1968,6 +1979,8 @@ void DebuggerManager::updateWatchersWindow()
 {
     d->m_watchersWindow->setVisible(
         d->m_watchHandler->model(WatchersWatch)->rowCount(QModelIndex()) > 0);
+    d->m_returnWindow->setVisible(
+        d->m_watchHandler->model(ReturnWatch)->rowCount(QModelIndex()) > 0);
 }
 
 void DebuggerManager::openTextEditor(const QString &titlePattern,

src/plugins/debugger/gdb/gdbengine.cpp

@@ -274,6 +274,7 @@ void GdbEngine::initializeVariables()
     m_pendingLogStreamOutput.clear();
 
     m_inbuffer.clear();
+    m_resultVarName.clear();
 
     m_commandTimer->stop();
 
@@ -1290,7 +1291,7 @@ void GdbEngine::handleStopResponse(const GdbMi &data)
     }
 #endif
 
-    // seen on XP after removing a breakpoint while running
+    // This was seen on XP after removing a breakpoint while running
     //  >945*stopped,reason="signal-received",signal-name="SIGTRAP",
     //  signal-meaning="Trace/breakpoint trap",thread-id="2",
     //  frame={addr="0x7c91120f",func="ntdll!DbgUiConnectToDbg",
@@ -1333,6 +1334,18 @@ void GdbEngine::handleStopResponse(const GdbMi &data)
         }
     }
 
+    // Show return value if possible, usually with reason "function-finished".
+    // *stopped,reason="function-finished",frame={addr="0x080556da",
+    // func="testReturnValue",args=[],file="/../app.cpp",
+    // fullname="/../app.cpp",line="1611"},gdb-result-var="$1",
+    // return-value="{d = 0x808d998}",thread-id="1",stopped-threads="all",
+    // core="1"
+    GdbMi resultVar = data.findChild("gdb-result-var");
+    if (resultVar.isValid())
+        m_resultVarName = resultVar.data();
+    else
+        m_resultVarName.clear();
+
     bool initHelpers = m_debuggingHelperState == DebuggingHelperUninitialized
                        || m_debuggingHelperState == DebuggingHelperLoadTried;
     // Don't load helpers on stops triggered by signals unless it's

src/plugins/debugger/gdb/gdbengine.h

@@ -170,6 +170,10 @@ private:
 
     AbstractGdbAdapter *m_gdbAdapter;
 
+    // Name of the convenience variable containing the last
+    // known function return value.
+    QByteArray m_resultVarName;
+
 private: ////////// Gdb Command Management //////////
 
     public: // Otherwise the Qt flag macros are unhappy.

src/plugins/debugger/gdb/pythongdbengine.cpp

@@ -85,8 +85,12 @@ void GdbEngine::updateLocalsPython(const QByteArray &varList)
         options += "defaults,";
     options.chop(1);
 
+    QByteArray resultVar;
+    if (!m_resultVarName.isEmpty())
+        resultVar = "resultvarname:" + m_resultVarName + ' ';
+
     postCommand("bb options:" + options + " vars:" + varList + ' '
-            + expanded + " watchers:" + watchers.toHex(),
+            + resultVar + expanded + " watchers:" + watchers.toHex(),
         WatchUpdate, CB(handleStackFramePython));
 }
 

src/plugins/debugger/watchhandler.cpp

@@ -120,6 +120,10 @@ WatchModel::WatchModel(WatchHandler *handler, WatchType type)
     m_root->parent = 0;
 
     switch (m_type) {
+        case ReturnWatch:
+            m_root->iname = "return";
+            m_root->name = WatchHandler::tr("Return Value");
+            break;
         case LocalsWatch:
             m_root->iname = "local";
             m_root->name = WatchHandler::tr("Locals");
@@ -964,6 +968,7 @@ WatchHandler::WatchHandler(DebuggerManager *manager)
     m_expandPointers = true;
     m_inChange = false;
 
+    m_return = new WatchModel(this, ReturnWatch);
     m_locals = new WatchModel(this, LocalsWatch);
     m_watchers = new WatchModel(this, WatchersWatch);
     m_tooltips = new WatchModel(this, TooltipsWatch);
@@ -981,6 +986,7 @@ WatchHandler::WatchHandler(DebuggerManager *manager)
 void WatchHandler::beginCycle()
 {
     ++generationCounter;
+    m_return->beginCycle();
     m_locals->beginCycle();
     m_watchers->beginCycle();
     m_tooltips->beginCycle();
@@ -988,6 +994,7 @@ void WatchHandler::beginCycle()
 
 void WatchHandler::endCycle()
 {
+    m_return->endCycle();
     m_locals->endCycle();
     m_watchers->endCycle();
     m_tooltips->endCycle();
@@ -997,8 +1004,10 @@ void WatchHandler::endCycle()
 void WatchHandler::cleanup()
 {
     m_expandedINames.clear();
+    m_return->reinitialize();
     m_locals->reinitialize();
     m_tooltips->reinitialize();
+    m_return->m_fetchTriggered.clear();
     m_locals->m_fetchTriggered.clear();
     m_watchers->m_fetchTriggered.clear();
     m_tooltips->m_fetchTriggered.clear();
@@ -1014,6 +1023,7 @@ void WatchHandler::cleanup()
 
 void WatchHandler::emitAllChanged()
 {
+    m_return->emitAllChanged();
     m_locals->emitAllChanged();
     m_watchers->emitAllChanged();
     m_tooltips->emitAllChanged();
@@ -1337,6 +1347,7 @@ void WatchHandler::loadSessionData()
 WatchModel *WatchHandler::model(WatchType type) const
 {
     switch (type) {
+        case ReturnWatch: return m_return;
         case LocalsWatch: return m_locals;
         case WatchersWatch: return m_watchers;
         case TooltipsWatch: return m_tooltips;
@@ -1347,6 +1358,8 @@ WatchModel *WatchHandler::model(WatchType type) const
 
 WatchModel *WatchHandler::modelForIName(const QByteArray &iname) const
 {
+    if (iname.startsWith("return"))
+        return m_return;
     if (iname.startsWith("local"))
         return m_locals;
     if (iname.startsWith("tooltip"))
@@ -1374,6 +1387,7 @@ void WatchHandler::setFormat(const QString &type, int format)
 {
     m_typeFormats[type] = format;
     saveTypeFormats();
+    m_return->emitDataChanged(1);
     m_locals->emitDataChanged(1);
     m_watchers->emitDataChanged(1);
     m_tooltips->emitDataChanged(1);

src/plugins/debugger/watchhandler.h

@@ -51,7 +51,7 @@ namespace Internal {
 
 class WatchItem;
 class WatchHandler;
-enum WatchType { LocalsWatch, WatchersWatch, TooltipsWatch };
+enum WatchType { ReturnWatch, LocalsWatch, WatchersWatch, TooltipsWatch };
 
 enum WatchRoles
 {
@@ -206,6 +206,7 @@ private:
     // Items expanded in the Locals & Watchers view.
     QSet<QByteArray> m_expandedINames; 
 
+    WatchModel *m_return;
     WatchModel *m_locals;
     WatchModel *m_watchers;
     WatchModel *m_tooltips;

src/plugins/debugger/watchwindow.h

@@ -48,7 +48,7 @@ class WatchWindow : public QTreeView
     Q_OBJECT
 
 public:
-    enum Type { LocalsType, TooltipType, WatchersType };
+    enum Type { ReturnType, LocalsType, TooltipType, WatchersType };
 
     WatchWindow(Type type, DebuggerManager *manager, QWidget *parent = 0);
     void setType(Type type) { m_type = type; }