From 3c0cd7566cf858d0fd23fecad5ef9faec798cf5f Mon Sep 17 00:00:00 2001
From: Olivier Goffart <ogoffart@woboq.com>
Date: Wed, 11 Dec 2019 12:18:58 +0100
Subject: Export an extern template for QMetaTypeForType for builtin types

That way not every translation unit generates the QMetaTypeInterface
for the builtin types

Change-Id: Id703c14532646a58f4088e8f3914564ce35e398e
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
---
 src/corelib/kernel/qmetatype.cpp | 13 +++++++++++++
 src/corelib/kernel/qmetatype.h   | 18 ++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/src/corelib/kernel/qmetatype.cpp b/src/corelib/kernel/qmetatype.cpp
index 52f36aa7ce..2e5b18501a 100644
--- a/src/corelib/kernel/qmetatype.cpp
+++ b/src/corelib/kernel/qmetatype.cpp
@@ -1755,4 +1755,17 @@ const bool VectorBoolElements::true_element = true;
 const bool VectorBoolElements::false_element = false;
 }
 
+namespace QtPrivate {
+#ifndef QT_BOOTSTRAPPED
+// Explicit instantiation definition
+#define QT_METATYPE_DECLARE_TEMPLATE_ITER(TypeName, Id, Name) template class QMetaTypeForType<Name>;
+QT_FOR_EACH_STATIC_PRIMITIVE_TYPE(QT_METATYPE_DECLARE_TEMPLATE_ITER)
+QT_FOR_EACH_STATIC_PRIMITIVE_POINTER(QT_METATYPE_DECLARE_TEMPLATE_ITER)
+QT_FOR_EACH_STATIC_CORE_CLASS(QT_METATYPE_DECLARE_TEMPLATE_ITER)
+QT_FOR_EACH_STATIC_CORE_POINTER(QT_METATYPE_DECLARE_TEMPLATE_ITER)
+QT_FOR_EACH_STATIC_CORE_TEMPLATE(QT_METATYPE_DECLARE_TEMPLATE_ITER)
+#undef QT_METATYPE_DECLARE_TEMPLATE_ITER
+#endif
+}
+
 QT_END_NAMESPACE
diff --git a/src/corelib/kernel/qmetatype.h b/src/corelib/kernel/qmetatype.h
index 7ee6a2662d..f9d7fe9f03 100644
--- a/src/corelib/kernel/qmetatype.h
+++ b/src/corelib/kernel/qmetatype.h
@@ -2723,6 +2723,24 @@ QMetaTypeInterface QMetaTypeForType<T>::metaType = {
 template<typename T>
 constexpr const decltype(typenameHelper<T>()) QMetaTypeForType<T>::name = typenameHelper<T>();
 
+template<>
+class QMetaTypeForType<void>
+{
+};
+
+#ifndef QT_BOOTSTRAPPED
+#define QT_METATYPE_DECLARE_EXTERN_TEMPLATE_ITER(TypeName, Id, Name)                               \
+    extern template class Q_CORE_EXPORT QMetaTypeForType<Name>;
+QT_WARNING_PUSH
+QT_WARNING_DISABLE_GCC("-Wattributes") // false positive because of QMetaTypeForType<void>
+QT_FOR_EACH_STATIC_PRIMITIVE_TYPE(QT_METATYPE_DECLARE_EXTERN_TEMPLATE_ITER)
+QT_WARNING_POP
+QT_FOR_EACH_STATIC_PRIMITIVE_POINTER(QT_METATYPE_DECLARE_EXTERN_TEMPLATE_ITER)
+QT_FOR_EACH_STATIC_CORE_CLASS(QT_METATYPE_DECLARE_EXTERN_TEMPLATE_ITER)
+QT_FOR_EACH_STATIC_CORE_POINTER(QT_METATYPE_DECLARE_EXTERN_TEMPLATE_ITER)
+QT_FOR_EACH_STATIC_CORE_TEMPLATE(QT_METATYPE_DECLARE_EXTERN_TEMPLATE_ITER)
+#undef QT_METATYPE_DECLARE_EXTERN_TEMPLATE_ITER
+#endif
 
 template<typename T>
 constexpr QMetaTypeInterface *qMetaTypeIntefaceForType()
-- 
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