Merge topic 'vs-version-for-unity' into release-3.16

9135954e2f VS: Do not use native unity builds on VS 2017 versions less than 15.8

Acked-by: Kitware Robot <[email protected]>
Merge-request: !4324

Source/cmGlobalVisualStudio10Generator.cxx

@@ -230,6 +230,12 @@ bool cmGlobalVisualStudio10Generator::SetGeneratorToolset(
     }
   }
 
+  this->SupportsUnityBuilds =
+    this->Version >= cmGlobalVisualStudioGenerator::VS16 ||
+    (this->Version == cmGlobalVisualStudioGenerator::VS15 &&
+     cmSystemTools::PathExists(this->VCTargetsPath +
+                               "/Microsoft.Cpp.Unity.targets"));
+
   if (this->GeneratorToolsetCuda.empty()) {
     // Find the highest available version of the CUDA tools.
     std::vector<std::string> cudaTools;

Source/cmGlobalVisualStudio10Generator.h

@@ -108,6 +108,8 @@ public:
   virtual bool IsDefaultToolset(const std::string& version) const;
   virtual std::string GetAuxiliaryToolset() const;
 
+  bool GetSupportsUnityBuilds() const { return this->SupportsUnityBuilds; }
+
   bool FindMakeProgram(cmMakefile* mf) override;
 
   bool IsIPOSupported() const override { return true; }
@@ -172,6 +174,7 @@ protected:
   std::string DefaultMasmFlagTableName;
   std::string DefaultNasmFlagTableName;
   std::string DefaultRCFlagTableName;
+  bool SupportsUnityBuilds = false;
   bool SystemIsWindowsCE;
   bool SystemIsWindowsPhone;
   bool SystemIsWindowsStore;

Source/cmVisualStudio10TargetGenerator.cxx

@@ -2091,9 +2091,7 @@ void cmVisualStudio10TargetGenerator::WriteAllSources(Elem& e0)
   const bool haveUnityBuild =
     this->GeneratorTarget->GetPropertyAsBool("UNITY_BUILD");
 
-  if (haveUnityBuild &&
-      this->GlobalGenerator->GetVersion() >=
-        cmGlobalVisualStudioGenerator::VS15) {
+  if (haveUnityBuild && this->GlobalGenerator->GetSupportsUnityBuilds()) {
     Elem e1(e0, "PropertyGroup");
     e1.Element("EnableUnitySupport", "true");
   }
@@ -2199,9 +2197,7 @@ void cmVisualStudio10TargetGenerator::WriteAllSources(Elem& e0)
       this->WriteSource(e2, si.Source);
 
       bool useNativeUnityBuild = false;
-      if (haveUnityBuild &&
-          this->GlobalGenerator->GetVersion() >=
-            cmGlobalVisualStudioGenerator::VS15) {
+      if (haveUnityBuild && this->GlobalGenerator->GetSupportsUnityBuilds()) {
         // Magic value taken from cmGlobalVisualStudioVersionedGenerator.cxx
         static const std::string vs15 = "141";
         std::string toolset =
@@ -2228,7 +2224,7 @@ void cmVisualStudio10TargetGenerator::WriteAllSources(Elem& e0)
             si.Source->GetProperty("UNITY_SOURCE_FILE"));
           e2.Attribute("UnityFilesDirectory", unityDir);
         } else {
-          // Visual Studio versions prior to 2017 do not know about unity
+          // Visual Studio versions prior to 2017 15.8 do not know about unity
           // builds, thus we exclude the files alredy part of unity sources.
           if (!si.Source->GetPropertyAsBool("SKIP_UNITY_BUILD_INCLUSION")) {
             exclude_configs = si.Configs;