Unity Build: Fix per-config sources in multi-config generators

Single-config generators already support unity builds with per-config
sources because they compute sources using `CMAKE_BUILD_TYPE` as the
configuration.  Each original source is either included in the unity
build source, or not.

Teach multi-config generators to compute the list of sources for
inclusion in unity builds using all configurations.  Previously they
only used the empty string as the configuration.  Each original source
may be included in some configurations, but not others.  Use
preprocessor conditions to guard their inclusion when necessary.

Fixes: #22892

1 files changed, 10 insertions, 2 deletions

diff --git a/Source/cmLocalGenerator.h b/Source/cmLocalGenerator.h
index 4c9714ba03..726817adea 100644
--- a/Source/cmLocalGenerator.h
+++ b/Source/cmLocalGenerator.h
@@ -14,6 +14,8 @@
 #include <utility>
 #include <vector>
 
+#include <cm/optional>
+
 #include <cm3p/kwiml/int.h>
 
 #include "cmCustomCommandTypes.h"
@@ -664,6 +666,7 @@ private:
   struct UnityBatchedSource
   {
     cmSourceFile* Source = nullptr;
+    std::vector<size_t> Configs;
     UnityBatchedSource(cmSourceFile* sf)
       : Source(sf)
     {
@@ -672,27 +675,32 @@ private:
   struct UnitySource
   {
     std::string Path;
-    UnitySource(std::string path)
+    bool PerConfig = false;
+    UnitySource(std::string path, bool perConfig)
       : Path(std::move(path))
+      , PerConfig(perConfig)
     {
     }
   };
 
   UnitySource WriteUnitySource(
-    cmGeneratorTarget* target,
+    cmGeneratorTarget* target, std::vector<std::string> const& configs,
     cmRange<std::vector<UnityBatchedSource>::const_iterator> sources,
     cmValue beforeInclude, cmValue afterInclude, std::string filename) const;
   void WriteUnitySourceInclude(std::ostream& unity_file,
+                               cm::optional<std::string> const& cond,
                                std::string const& sf_full_path,
                                cmValue beforeInclude, cmValue afterInclude,
                                cmValue uniqueIdName) const;
   std::vector<UnitySource> AddUnityFilesModeAuto(
     cmGeneratorTarget* target, std::string const& lang,
+    std::vector<std::string> const& configs,
     std::vector<UnityBatchedSource> const& filtered_sources,
     cmValue beforeInclude, cmValue afterInclude,
     std::string const& filename_base, size_t batchSize);
   std::vector<UnitySource> AddUnityFilesModeGroup(
     cmGeneratorTarget* target, std::string const& lang,
+    std::vector<std::string> const& configs,
     std::vector<UnityBatchedSource> const& filtered_sources,
     cmValue beforeInclude, cmValue afterInclude,
     std::string const& filename_base);