Clang: Warn of potentially expensive checks

...for the code model.

If a diagnostic configuration with potentially expensive checks is
selected in Options/Preferences > C++ > Code Model, show a warning below
the combo box.

Change-Id: I52c5c2e229fd50c0fd82f70154fb5b727726ba31
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@qt.io>
Reviewed-by: Ivan Donchevskii <ivan.donchevskii@qt.io>
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/clangtools/clangtoolsconstants.h

@@ -28,6 +28,7 @@
 namespace ClangTools {
 namespace Constants {
 
+const char SETTINGS_PAGE_ID[] = "Analyzer.ClangTools.Settings";
 const char SETTINGS_ID[] = "ClangTools";
 const char CLANGTIDYCLAZY_RUN_MODE[] = "ClangTidyClazy.RunMode";
 

src/plugins/clangtools/clangtoolsplugin.cpp

@@ -73,7 +73,7 @@ class ClangToolsOptionsPage : public Core::IOptionsPage
 public:
     explicit ClangToolsOptionsPage()
     {
-        setId("Analyzer.ClangTools.Settings");
+        setId(Constants::SETTINGS_PAGE_ID);
         setDisplayName(QCoreApplication::translate(
                            "ClangTools::Internal::ClangToolsOptionsPage",
                            "Clang Tools"));

src/plugins/cpptools/cppcodemodelsettingspage.cpp

@@ -28,10 +28,13 @@
 #include "clangdiagnosticconfigswidget.h"
 #include "cppmodelmanager.h"
 #include "cpptoolsconstants.h"
+#include "cpptoolsreuse.h"
 #include "ui_cppcodemodelsettingspage.h"
 
+#include <clangtools/clangtoolsconstants.h> // for opening the respective options page
 #include <coreplugin/icore.h>
 #include <utils/algorithm.h>
+#include <utils/utilsicons.h>
 
 #include <QTextStream>
 
@@ -43,6 +46,12 @@ CppCodeModelSettingsWidget::CppCodeModelSettingsWidget(QWidget *parent)
     , m_ui(new Ui::CppCodeModelSettingsPage)
 {
     m_ui->setupUi(this);
+    m_ui->expensiveChecksHintIcon->setPixmap(Utils::Icons::WARNING.pixmap());
+    m_ui->expensiveChecksHintIcon->setVisible(false);
+    m_ui->expensiveChecksHintText->setVisible(false);
+    connect(m_ui->expensiveChecksHintText, &QLabel::linkActivated, [](const QString &){
+        Core::ICore::showOptionsDialog(ClangTools::Constants::SETTINGS_PAGE_ID);
+    });
 }
 
 CppCodeModelSettingsWidget::~CppCodeModelSettingsWidget()
@@ -69,6 +78,20 @@ void CppCodeModelSettingsWidget::applyToSettings() const
         m_settings->toSettings(Core::ICore::settings());
 }
 
+static bool hasConfigExpensiveChecks(const Core::Id &configId)
+{
+    if (!configId.isValid())
+        return false;
+
+    const ClangDiagnosticConfig config
+        = ClangDiagnosticConfigsModel(
+              codeModelSettings()->clangCustomDiagnosticConfigs())
+              .configWithId(configId);
+
+    return !config.clazyChecks().isEmpty()
+        || config.clangTidyMode() != ClangDiagnosticConfig::TidyMode::Disabled;
+}
+
 void CppCodeModelSettingsWidget::setupClangCodeModelWidgets()
 {
     const bool isClangActive = CppModelManager::instance()->isClangCodeModelActive();
@@ -88,6 +111,17 @@ void CppCodeModelSettingsWidget::setupClangCodeModelWidgets()
         if (applyClangCodeModelWidgetsToSettings())
             m_settings->toSettings(Core::ICore::settings());
     });
+
+    const auto checkForExpensiveChecks = [this](const Core::Id &configId) {
+        const bool visible = hasConfigExpensiveChecks(configId);
+        m_ui->expensiveChecksHintIcon->setVisible(visible);
+        m_ui->expensiveChecksHintText->setVisible(visible);
+    };
+
+    checkForExpensiveChecks(m_ui->clangDiagnosticConfigsSelectionWidget->currentConfigId());
+    connect(m_ui->clangDiagnosticConfigsSelectionWidget,
+            &ClangDiagnosticConfigsSelectionWidget::currentConfigChanged,
+            checkForExpensiveChecks);
 }
 
 void CppCodeModelSettingsWidget::setupGeneralWidgets()

src/plugins/cpptools/cppcodemodelsettingspage.ui

@@ -6,7 +6,7 @@
    <rect>
     <x>0</x>
     <y>0</y>
-    <width>629</width>
+    <width>647</width>
     <height>440</height>
    </rect>
   </property>
@@ -106,6 +106,40 @@
       <item>
        <widget class="CppTools::ClangDiagnosticConfigsSelectionWidget" name="clangDiagnosticConfigsSelectionWidget" native="true"/>
       </item>
+      <item>
+       <layout class="QHBoxLayout" name="horizontalLayout_2">
+        <item>
+         <widget class="QLabel" name="expensiveChecksHintIcon">
+          <property name="text">
+           <string/>
+          </property>
+          <property name="alignment">
+           <set>Qt::AlignLeading|Qt::AlignLeft|Qt::AlignTop</set>
+          </property>
+         </widget>
+        </item>
+        <item>
+         <widget class="QLabel" name="expensiveChecksHintText">
+          <property name="text">
+           <string>The selected configuration has potentially expensive Clang-Tidy or Clazy checks enabled.&lt;br/&gt;Consider to run these in a separate &lt;a href=&quot;target&quot;&gt;Clang-Tidy and Clazy analyzer&lt;/a&gt; run.</string>
+          </property>
+         </widget>
+        </item>
+        <item>
+         <spacer name="horizontalSpacer_2">
+          <property name="orientation">
+           <enum>Qt::Horizontal</enum>
+          </property>
+          <property name="sizeHint" stdset="0">
+           <size>
+            <width>40</width>
+            <height>20</height>
+           </size>
+          </property>
+         </spacer>
+        </item>
+       </layout>
+      </item>
      </layout>
     </widget>
    </item>