Only show Visual Studio compilers if VS is installed

Task-number: QTCREATORBUG-8487

Change-Id: Ibc812f14cd8e4de765cabf27d23451c06611d372
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Daniel Teske <daniel.teske@digia.com>

src/plugins/projectexplorer/msvctoolchain.cpp

@@ -440,6 +440,19 @@ QString MsvcToolChainFactory::id() const
     return QLatin1String(Constants::MSVC_TOOLCHAIN_ID);
 }
 
+bool MsvcToolChainFactory::checkForVisualStudioInstallation(const QString &vsName)
+{
+    const QSettings vsRegistry(
+#ifdef Q_OS_WIN64
+                QLatin1String("HKEY_LOCAL_MACHINE\\SOFTWARE\\Wow6432Node\\Microsoft\\VisualStudio\\SxS\\VS7"),
+#else
+                QLatin1String("HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\VisualStudio\\SxS\\VS7"),
+#endif
+                QSettings::NativeFormat);
+
+    return vsRegistry.contains(vsName);
+}
+
 QList<ToolChain *> MsvcToolChainFactory::autoDetect()
 {
     QList<ToolChain *> results;
@@ -501,6 +514,8 @@ QList<ToolChain *> MsvcToolChainFactory::autoDetect()
         const int dotPos = vsName.indexOf(QLatin1Char('.'));
         if (dotPos == -1)
             continue;
+        if (!checkForVisualStudioInstallation(vsName))
+            continue;
 
         const QString path = vsRegistry.value(vsName).toString();
         const int version = vsName.left(dotPos).toInt();

src/plugins/projectexplorer/msvctoolchain.h

@@ -106,6 +106,8 @@ public:
         { return MsvcToolChain::readFromMap(data); }
 
     ToolChainConfigWidget *configurationWidget(ToolChain *);
+private:
+    static bool checkForVisualStudioInstallation(const QString &vsName);
 };
 
 // --------------------------------------------------------------------------