From 8d2b2c0f566f225c0a8b1c17a30c1068b860926e Mon Sep 17 00:00:00 2001
From: Vadim Zeitlin <vadim@wxwidgets.org>
Date: Sun, 29 Sep 2019 22:59:50 +0200
Subject: [PATCH] Add wxMSVC_VERSION_ABI_COMPAT

This symbol can be predefined to use the libraries built with "vc14x" as
the compiler prefix. This can be useful to reuse the same binaries for
all ABI-compatible VC 14.x versions: 14.0 (MSVS 2015), 14.1 (2017) and
14.2 (2019).
---
 docs/doxygen/mainpages/const_cpp.h |  7 ++++++-
 include/msvc/wx/setup.h            | 29 ++++++++++++++++++++++-------
 2 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/docs/doxygen/mainpages/const_cpp.h b/docs/doxygen/mainpages/const_cpp.h
index 79ac183596..2da7c6989f 100644
--- a/docs/doxygen/mainpages/const_cpp.h
+++ b/docs/doxygen/mainpages/const_cpp.h
@@ -226,7 +226,12 @@ vc140 <em>before</em> include @c wx/setup.h file, i.e. typically in the MSVS
 project options. Alternatively, you can predefine @c wxMSVC_VERSION_AUTO symbol
 (without any value), which means that the appropriate compiler version should
 be used automatically, e.g. "vc100" for VC 10 (MSVS 2010), "vc140" for VC 14
-(MSVS 2015) etc.
+(MSVS 2015) etc. Additionally, VC 14 is a special case as it has 3 minor
+versions: VC 14.0, 14.1 and 14.2, corresponding to MSVS 2015, 2017 and 2019;
+that are ABI-compatible with each other. Due to this, it can also be useful to
+reuse the single build of wxWidgets with all versions of the compiler and this
+is supported if @c wxMSVC_VERSION_ABI_COMPAT is defined: the compiler prefix
+"vc14x" is used in this case.
 
 If the makefiles have been used to build the libraries from source and the @c CFG
 variable has been set to specify a different output path for that particular
diff --git a/include/msvc/wx/setup.h b/include/msvc/wx/setup.h
index 61a62d39fc..40217c9648 100644
--- a/include/msvc/wx/setup.h
+++ b/include/msvc/wx/setup.h
@@ -44,9 +44,16 @@
 // COMPILER_PREFIX=vcXX and in this case you may want to either predefine
 // wxMSVC_VERSION as "XX" or define wxMSVC_VERSION_AUTO to use the appropriate
 // version depending on the compiler used
+//
+// There is an additional complication with MSVC 14.0, 14.1 and 14.2 versions
+// (a.k.a. MSVS 2015, 2017 and 2019): as they're all ABI-compatible with each
+// other, it is convenient to use the same "vc14x" compiler prefix for all of
+// them, but this is not how wxMSVC_VERSION_AUTO behaves by default, so you
+// need to additionally define wxMSVC_VERSION_ABI_COMPAT to opt in into using
+// this "vc14x" prefix.
 #ifdef wxMSVC_VERSION
     #define wxCOMPILER_PREFIX wxCONCAT(vc, wxMSVC_VERSION)
-#elif defined(wxMSVC_VERSION_AUTO)
+#elif defined(wxMSVC_VERSION_AUTO) || defined(wxMSVC_VERSION_ABI_COMPAT)
     #if _MSC_VER == 1200
         #define wxCOMPILER_PREFIX vc60
     #elif _MSC_VER == 1300
@@ -63,12 +70,20 @@
         #define wxCOMPILER_PREFIX vc110
     #elif _MSC_VER == 1800
         #define wxCOMPILER_PREFIX vc120
-    #elif _MSC_VER == 1900
-        #define wxCOMPILER_PREFIX vc140
-    #elif _MSC_VER >= 1910 && _MSC_VER < 1920
-        #define wxCOMPILER_PREFIX vc141
-    #elif _MSC_VER >= 1920 && _MSC_VER < 2000
-        #define wxCOMPILER_PREFIX vc142
+    #elif _MSC_VER >= 1900 && _MSC_VER < 2000
+        #ifdef wxMSVC_VERSION_ABI_COMPAT
+            #define wxCOMPILER_PREFIX vc14x
+        #else
+            #if _MSC_VER < 1910
+                #define wxCOMPILER_PREFIX vc140
+            #elif _MSC_VER >= 1910 && _MSC_VER < 1920
+                #define wxCOMPILER_PREFIX vc141
+            #elif _MSC_VER >= 1920 && _MSC_VER < 2000
+                #define wxCOMPILER_PREFIX vc142
+            #else
+                #error "Unknown MSVC 14.x compiler version, please report to wx-dev."
+            #endif
+        #endif
     #else
         #error "Unknown MSVC compiler version, please report to wx-dev."
     #endif