Cleanup: use extern templates for typed output attribute

This is very similar to rBa812fe8ceb75fd2b.
This time the number of symbols decreases further from 1335 to 928.
Compile time of the distribute node decreases from ~2.4s to ~2.3s.

3 files changed, 50 insertions, 3 deletions

diff --git a/source/blender/blenkernel/BKE_attribute_access.hh b/source/blender/blenkernel/BKE_attribute_access.hh
index ef43e21b739..baa918d9949 100644
--- a/source/blender/blenkernel/BKE_attribute_access.hh
+++ b/source/blender/blenkernel/BKE_attribute_access.hh
@@ -248,7 +248,7 @@ template<typename T> class OutputAttribute_Typed {
   VMutableArray<T> *varray_ = nullptr;
 
  public:
-  OutputAttribute_Typed() = default;
+  OutputAttribute_Typed();
   OutputAttribute_Typed(OutputAttribute attribute) : attribute_(std::move(attribute))
   {
     if (attribute_) {
@@ -257,8 +257,8 @@ template<typename T> class OutputAttribute_Typed {
     }
   }
 
-  OutputAttribute_Typed(OutputAttribute_Typed &&other) = default;
-  ~OutputAttribute_Typed() = default;
+  OutputAttribute_Typed(OutputAttribute_Typed &&other);
+  ~OutputAttribute_Typed();
 
   OutputAttribute_Typed &operator=(OutputAttribute_Typed &&other)
   {
@@ -316,6 +316,13 @@ template<typename T> class OutputAttribute_Typed {
   }
 };
 
+/* These are not defined in the class directly, because when defining them there, the external
+ * template instantiation does not work, resulting in longer compile times. */
+template<typename T> inline OutputAttribute_Typed<T>::OutputAttribute_Typed() = default;
+template<typename T>
+inline OutputAttribute_Typed<T>::OutputAttribute_Typed(OutputAttribute_Typed &&other) = default;
+template<typename T> inline OutputAttribute_Typed<T>::~OutputAttribute_Typed() = default;
+
 /**
  * A basic container around DNA CustomData so that its users
  * don't have to implement special copy and move constructors.
@@ -501,3 +508,15 @@ template<typename T> inline MutableSpan<T> OutputAttribute::as_span()
 }
 
 }  // namespace blender::bke
+
+/* --------------------------------------------------------------------
+ * Extern template instantiations that are defined in `intern/extern_implementations.cc`.
+ */
+
+namespace blender::bke {
+extern template class OutputAttribute_Typed<float>;
+extern template class OutputAttribute_Typed<int>;
+extern template class OutputAttribute_Typed<float3>;
+extern template class OutputAttribute_Typed<bool>;
+extern template class OutputAttribute_Typed<ColorGeometry4f>;
+}  // namespace blender::bke
diff --git a/source/blender/blenkernel/CMakeLists.txt b/source/blender/blenkernel/CMakeLists.txt
index fb7fdd1ac21..5a4bc148c0a 100644
--- a/source/blender/blenkernel/CMakeLists.txt
+++ b/source/blender/blenkernel/CMakeLists.txt
@@ -134,6 +134,7 @@ set(SRC
   intern/editmesh_cache.c
   intern/editmesh_tangent.c
   intern/effect.c
+  intern/extern_implementations.cc
   intern/fcurve.c
   intern/fcurve_cache.c
   intern/fcurve_driver.c
diff --git a/source/blender/blenkernel/intern/extern_implementations.cc b/source/blender/blenkernel/intern/extern_implementations.cc
new file mode 100644
index 00000000000..07a4b6fc455
--- /dev/null
+++ b/source/blender/blenkernel/intern/extern_implementations.cc
@@ -0,0 +1,27 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#include "BKE_attribute_access.hh"
+
+namespace blender::bke {
+
+template class OutputAttribute_Typed<float>;
+template class OutputAttribute_Typed<int>;
+template class OutputAttribute_Typed<float3>;
+template class OutputAttribute_Typed<bool>;
+template class OutputAttribute_Typed<ColorGeometry4f>;
+
+}  // namespace blender::bke