cmNinjaTargetGenerator: do not order-depend on C++ module sources

C++ module sources should not be included by any other TUs, so their
presence cannot matter for order-only dependencies of the entire target.
Exclude them.

Update CMP0154 to take this into consideration and add tests to the
`CXXModules` suite (which already deals with module support detection).

1 files changed, 9 insertions, 4 deletions

diff --git a/Source/cmNinjaTargetGenerator.cxx b/Source/cmNinjaTargetGenerator.cxx
index bb1d6f2..05b6690 100644
--- a/Source/cmNinjaTargetGenerator.cxx
+++ b/Source/cmNinjaTargetGenerator.cxx
@@ -1059,13 +1059,18 @@ void cmNinjaTargetGenerator::WriteObjectBuildStatements(
           cmFileSet const* fileset =
             this->GeneratorTarget->GetFileSetForSource(
               config, this->Makefile->GetOrCreateGeneratedSource(*it));
-          if (fileset &&
-              cmFileSetVisibilityIsForInterface(fileset->GetVisibility())) {
+          bool isVisible = fileset &&
+            cmFileSetVisibilityIsForInterface(fileset->GetVisibility());
+          bool isIncludeable =
+            !fileset || cmFileSetTypeCanBeIncluded(fileset->GetType());
+          if (fileset && isVisible && isIncludeable) {
             ++it;
-          } else {
+            continue;
+          }
+          if (!fileset || isIncludeable) {
             ccouts_private.push_back(*it);
-            it = ccouts.erase(it);
           }
+          it = ccouts.erase(it);
         }
       }
     }