Clang: Free us from specific Qt versions

More precisely, free us from specific Q_MOC_RUN/QT_NO_META_MACROS code
paths in QtCore/qobjectdefs.h.

In order to track signals and slots we provided custom definitions of
e.g. "Q_SIGNAL" by including qt5-qobjectdefs-injected.h with "-include".
We also had to ensure that those macros were not overwritten by Qt's
qobjectdefs.h, which we did by defining QT_NO_META_MACROS. However, this
came with a cost: we needed to replicate all the other macro definitions
in the Q_MOC_RUN/QT_NO_META_MACROS code path, e.g. Q_INTERFACES. This
bound us to specific versions of qobjectdefs.h and occasionally we had
to adapt (see change 4eafa2e02b).

The new approach wraps Qt's qobjectdefs.h with the help of
"include_next". In the wrapper header, we only redefine what is
necessary.

The "include_next" directive is originally a GNU extension. Clang seems
to support it unconditionally, as [1] implicitly states.

[1] http://clang.llvm.org/docs/LanguageExtensions.html#include-file-checking-macros

Change-Id: Ic1a263f94b178349cb32bfdbb074ad5e6e0761ee
Reviewed-by: Christian Kandeler <christian.kandeler@theqtcompany.com>
Reviewed-by: Erik Verbruggen <erik.verbruggen@theqtcompany.com>

share/qtcreator/cplusplus/wrappedQtHeaders/QtCore/qobjectdefs.h

@@ -28,44 +28,35 @@
 **
 ****************************************************************************/
 
-#define QT_NO_META_MACROS
+// Include qobjectdefs.h from Qt ...
+#include_next <qobjectdefs.h>
 
-#if defined(QT_NO_KEYWORDS)
-# define QT_NO_EMIT
-#else
-#  ifndef QT_NO_SIGNALS_SLOTS_KEYWORDS
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wmacro-redefined"
+
+// ...and redefine macros for tagging signals/slots
+#ifdef signals
 #  define signals public __attribute__((annotate("qt_signal")))
+#endif
+
+#ifdef slots
 #  define slots __attribute__((annotate("qt_slot")))
 #endif
-#endif
+
+#ifdef Q_SIGNALS
 #  define Q_SIGNALS public __attribute__((annotate("qt_signal")))
-#define Q_SLOTS slots __attribute__((annotate("qt_slot")))
-#define Q_SIGNAL __attribute__((annotate("qt_signal")))
-#define Q_SLOT __attribute__((annotate("qt_slot")))
-#define Q_PRIVATE_SLOT(d, signature)
-
-#define Q_EMIT
-#ifndef QT_NO_EMIT
-# define emit
 #endif
-#define Q_CLASSINFO(name, value)
-#define Q_PLUGIN_METADATA(x)
-#define Q_INTERFACES(x)
-#define Q_PROPERTY(text)
-#define Q_PRIVATE_PROPERTY(d, text)
-#define Q_REVISION(v)
-#define Q_OVERRIDE(text)
-#define Q_ENUMS(x)
-#define Q_FLAGS(x)
-#define Q_ENUM(x)
-#define Q_FLAG(x)
-#define Q_SCRIPTABLE
-#define Q_INVOKABLE
 
-#define Q_GADGET \
-public: \
-    static const QMetaObject staticMetaObject; \
-private:
+#ifdef Q_SLOTS
+#  define Q_SLOTS slots __attribute__((annotate("qt_slot")))
+#endif
 
-#define SIGNAL(a) #a
-#define SLOT(a) #a
+#ifdef Q_SIGNAL
+#  define Q_SIGNAL __attribute__((annotate("qt_signal")))
+#endif
+
+#ifdef Q_SLOT
+#  define Q_SLOT __attribute__((annotate("qt_slot")))
+#endif
+
+#pragma clang diagnostic pop

src/plugins/clangcodemodel/clangutils.cpp

@@ -130,8 +130,8 @@ public:
         optionsBuilder.addToolchainAndProjectDefines();
 
         optionsBuilder.addResourceDirOptions();
+        optionsBuilder.addWrappedQtHeadersIncludePath();
         optionsBuilder.addHeaderPathOptions();
-        optionsBuilder.addInjectedHeaderWithCustomQtMacros();
         optionsBuilder.addProjectConfigFileInclude();
 
         optionsBuilder.addExtraOptions();
@@ -160,19 +160,14 @@ private:
         }
     }
 
-    void addInjectedHeaderWithCustomQtMacros()
+    void addWrappedQtHeadersIncludePath()
     {
-        static const QString injectedHeader = ICore::instance()->resourcePath()
-                + QLatin1String("/cplusplus/qt%1-qobjectdefs-injected.h");
+        static const QString wrappedQtHeaders = ICore::instance()->resourcePath()
+                + QLatin1String("/cplusplus/wrappedQtHeaders");
 
-//        if (pPart->qtVersion == ProjectPart::Qt4) {
-//            builder.addOption(QLatin1String("-include"));
-//            builder.addOption(injectedHeader.arg(QLatin1Char('4')));
-//        }
-
-        if (m_projectPart->qtVersion == ProjectPart::Qt5) {
-            add(QLatin1String("-include"));
-            add(injectedHeader.arg(QLatin1Char('5')));
+        if (m_projectPart->qtVersion != ProjectPart::NoQt) {
+            add(QLatin1String("-I") + wrappedQtHeaders);
+            add(QLatin1String("-I") + wrappedQtHeaders + QLatin1String("/QtCore"));
         }
     }