VS: Convert GetIDEVersion to non-virtual table lookup

Source/cmGlobalVisualStudio10Generator.h

@@ -140,8 +140,6 @@ protected:
   virtual bool SelectWindowsPhoneToolset(std::string& toolset) const;
   virtual bool SelectWindowsStoreToolset(std::string& toolset) const;
 
-  const char* GetIDEVersion() const override { return "10.0"; }
-
   std::string const& GetMSBuildCommand();
 
   cmIDEFlagTable const* LoadFlagTable(std::string const& flagTableName,

Source/cmGlobalVisualStudio11Generator.h

@@ -43,7 +43,6 @@ protected:
   bool IsWindowsPhoneToolsetInstalled() const;
   bool IsWindowsStoreToolsetInstalled() const;
 
-  const char* GetIDEVersion() const override { return "11.0"; }
   bool UseFolderProperty() const override;
   static std::set<std::string> GetInstalledWindowsCESDKs();
 

Source/cmGlobalVisualStudio12Generator.h

@@ -43,7 +43,6 @@ protected:
   // of the toolset is installed
   bool IsWindowsPhoneToolsetInstalled() const;
   bool IsWindowsStoreToolsetInstalled() const;
-  const char* GetIDEVersion() const override { return "12.0"; }
 
 private:
   class Factory;

Source/cmGlobalVisualStudio14Generator.h

@@ -39,7 +39,6 @@ protected:
   // version of the toolset.
   virtual std::string GetWindows10SDKMaxVersion() const;
 
-  const char* GetIDEVersion() const override { return "14.0"; }
   virtual bool SelectWindows10SDK(cmMakefile* mf, bool required);
 
   // Used to verify that the Desktop toolset for the current generator is

Source/cmGlobalVisualStudio15Generator.h

@@ -37,8 +37,6 @@ protected:
   bool InitializeWindows(cmMakefile* mf) override;
   bool SelectWindowsStoreToolset(std::string& toolset) const override;
 
-  const char* GetIDEVersion() const override { return "15.0"; }
-
   // Used to verify that the Desktop toolset for the current generator is
   // installed on the machine.
   bool IsWindowsDesktopToolsetInstalled() const override;

Source/cmGlobalVisualStudio8Generator.h

@@ -49,7 +49,6 @@ public:
 
 protected:
   void AddExtraIDETargets() override;
-  const char* GetIDEVersion() const override { return "8.0"; }
 
   std::string FindDevEnvCommand() override;
 

Source/cmGlobalVisualStudio9Generator.h

@@ -36,9 +36,6 @@ public:
    */
   std::string GetUserMacrosRegKeyBase() override;
 
-protected:
-  const char* GetIDEVersion() const override { return "9.0"; }
-
 private:
   class Factory;
   friend class Factory;

Source/cmGlobalVisualStudioGenerator.cxx

@@ -43,6 +43,25 @@ void cmGlobalVisualStudioGenerator::SetVersion(VSVersion v)
   this->Version = v;
 }
 
+const char* cmGlobalVisualStudioGenerator::GetIDEVersion() const
+{
+  switch (this->Version) {
+    case cmGlobalVisualStudioGenerator::VS9:
+      return "9.0";
+    case cmGlobalVisualStudioGenerator::VS10:
+      return "10.0";
+    case cmGlobalVisualStudioGenerator::VS11:
+      return "11.0";
+    case cmGlobalVisualStudioGenerator::VS12:
+      return "12.0";
+    case cmGlobalVisualStudioGenerator::VS14:
+      return "14.0";
+    case cmGlobalVisualStudioGenerator::VS15:
+      return "15.0";
+  }
+  return "";
+}
+
 std::string cmGlobalVisualStudioGenerator::GetRegistryBase()
 {
   return cmGlobalVisualStudioGenerator::GetRegistryBase(this->GetIDEVersion());

Source/cmGlobalVisualStudioGenerator.h

@@ -137,7 +137,7 @@ protected:
   // below 8.
   virtual bool VSLinksDependencies() const { return true; }
 
-  virtual const char* GetIDEVersion() const = 0;
+  const char* GetIDEVersion() const;
 
   bool ComputeTargetDepends() override;
   class VSDependSet : public std::set<std::string>