Ninja Multi-Config: Make cross-config building opt-in

Many users will want to use the Ninja Multi-Config generator like a
traditional Visual Studio-style multi-config generator, which doesn't
mix configurations - custom commands are built using target executables
of the same configuration the command is for. We do not want to force
these people to generate an N*N build matrix when they only need N*1,
especially if they have lots of targets. Add a new variable,
CMAKE_NINJA_CROSS_CONFIG_ENABLE, to opt-in to the cross-config build
matrix.

1 files changed, 11 insertions, 2 deletions

diff --git a/Source/cmGlobalNinjaGenerator.cxx b/Source/cmGlobalNinjaGenerator.cxx
index 35b4f91..ea66e3d 100644
--- a/Source/cmGlobalNinjaGenerator.cxx
+++ b/Source/cmGlobalNinjaGenerator.cxx
@@ -1274,7 +1274,7 @@ void cmGlobalNinjaGenerator::WriteFolderTargets(std::ostream& os)
     }
 
     // Add target for all configs
-    if (this->IsMultiConfig()) {
+    if (this->EnableCrossConfigBuild()) {
       build.ExplicitDeps.clear();
       for (auto const& config : configs) {
         build.ExplicitDeps.push_back(this->BuildAlias(
@@ -1710,6 +1710,9 @@ void cmGlobalNinjaGenerator::WriteTargetClean(std::ostream& os)
           config));
       }
       for (auto const& fileConfig : configs) {
+        if (fileConfig != config && !this->EnableCrossConfigBuild()) {
+          continue;
+        }
         if (this->IsMultiConfig()) {
           build.Variables["FILE_ARG"] = cmStrCat(
             "-f ", cmGlobalNinjaMultiGenerator::GetNinjaFilename(fileConfig));
@@ -1718,7 +1721,7 @@ void cmGlobalNinjaGenerator::WriteTargetClean(std::ostream& os)
       }
     }
 
-    if (this->IsMultiConfig()) {
+    if (this->EnableCrossConfigBuild()) {
       build.Outputs.front() = this->BuildAlias(
         this->NinjaOutputPath(this->GetCleanTargetName()), "all");
       build.ExplicitDeps.clear();
@@ -2192,6 +2195,12 @@ bool cmGlobalNinjaGenerator::WriteDyndepFile(
   return true;
 }
 
+bool cmGlobalNinjaGenerator::EnableCrossConfigBuild() const
+{
+  return this->IsMultiConfig() &&
+    this->Makefiles.front()->IsOn("CMAKE_NINJA_CROSS_CONFIG_ENABLE");
+}
+
 int cmcmd_cmake_ninja_dyndep(std::vector<std::string>::const_iterator argBeg,
                              std::vector<std::string>::const_iterator argEnd)
 {