From 4e137d5cbb85c0344f4135ba6dc39bbf57f90e41 Mon Sep 17 00:00:00 2001
From: John Emmas <john@creativepost.co.uk>
Date: Tue, 10 Mar 2020 12:28:52 +0000
Subject: Avoid using 'boost::aligned_storage' which is known to be problematic
 in MSVC builds:-

https://www.boost.org/doc/libs/1_65_0/libs/type_traits/doc/html/boost_typetraits/reference/aligned_storage.html
---
 libs/ardour/ardour/chan_mapping.h  | 11 +++++++++++
 libs/ardour/ardour/plugin_insert.h | 12 +++++++++++-
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/libs/ardour/ardour/chan_mapping.h b/libs/ardour/ardour/chan_mapping.h
index cc42ed01bc..7a4d41123e 100644
--- a/libs/ardour/ardour/chan_mapping.h
+++ b/libs/ardour/ardour/chan_mapping.h
@@ -104,8 +104,19 @@ public:
 	 */
 	bool     is_subset (const ChanMapping& superset) const;
 
+#if defined(_MSC_VER) && (_MSC_VER < 1900)
+	/* Use the older (heap based) mapping for early versions of MSVC.
+	 * In fact it might be safer to use this for all MSVC builds - as
+	 * our StackAllocator class depends on 'boost::aligned_storage'
+	 * which is known to be troublesome with Visual C++ :-
+	 * https://www.boost.org/doc/libs/1_65_0/libs/type_traits/doc/html/boost_typetraits/reference/aligned_storage.html
+	 */
+	typedef std::map<uint32_t, uint32_t>    TypeMapping;
+	typedef std::map<DataType, TypeMapping> Mappings;
+#else
 	typedef std::map<uint32_t, uint32_t, std::less<uint32_t>, PBD::StackAllocator<std::pair<const uint32_t, uint32_t>, 16> > TypeMapping;
 	typedef std::map<DataType, TypeMapping, std::less<DataType>, PBD::StackAllocator<std::pair<const DataType, TypeMapping>, 2> > Mappings;
+#endif
 
 	Mappings        mappings()       { return _mappings; }
 	const Mappings& mappings() const { return _mappings; }
diff --git a/libs/ardour/ardour/plugin_insert.h b/libs/ardour/ardour/plugin_insert.h
index 003df28a38..3beaef9a15 100644
--- a/libs/ardour/ardour/plugin_insert.h
+++ b/libs/ardour/ardour/plugin_insert.h
@@ -371,7 +371,17 @@ private:
 	/* ordered map [plugin instance ID] => ARDOUR::ChanMapping
 	 * TODO: consider replacing with boost::flat_map<> or std::vector<>.
 	 */
-	class PinMappings : public std::map <uint32_t, ARDOUR::ChanMapping, std::less<uint32_t>, PBD::StackAllocator<std::pair<const uint32_t, ARDOUR::ChanMapping>, 4> > 
+#if defined(_MSC_VER) && (_MSC_VER < 1900)
+	/* Use the older (heap based) mapping for early versions of MSVC.
+	 * In fact it might be safer to use this for all MSVC builds - as
+	 * our StackAllocator class depends on 'boost::aligned_storage'
+	 * which is known to be troublesome with Visual C++ :-
+	 * https://www.boost.org/doc/libs/1_65_0/libs/type_traits/doc/html/boost_typetraits/reference/aligned_storage.html
+	 */
+	class PinMappings : public std::map <uint32_t, ARDOUR::ChanMapping>
+#else
+	class PinMappings : public std::map <uint32_t, ARDOUR::ChanMapping, std::less<uint32_t>, PBD::StackAllocator<std::pair<const uint32_t, ARDOUR::ChanMapping>, 4> >
+#endif
 	{
 		public:
 			/* this emulates C++11's  std::map::at()
-- 
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