Fortran: Restore support for TARGET_OBJECTS providing modules

Continue b665966933 (cmComputeLinkInformation: track OBJECT library
dependencies, 2023-07-22) which added explicitly listed `OBJECT`
libraries to the list of targets which the collator needs to consider.
Now also consider targets which provide objects directly to the target
via a `$<TARGET_OBJECT>` source lists.

Also add tests which use target objects directly and through an
`INTERFACE` library with target objects in its own sources.

Fixes: #25365

1 files changed, 19 insertions, 0 deletions

diff --git a/Source/cmComputeLinkDepends.cxx b/Source/cmComputeLinkDepends.cxx
index ce0df6b..4100135 100644
--- a/Source/cmComputeLinkDepends.cxx
+++ b/Source/cmComputeLinkDepends.cxx
@@ -26,6 +26,7 @@
 #include "cmMakefile.h"
 #include "cmMessageType.h"
 #include "cmRange.h"
+#include "cmSourceFile.h"
 #include "cmStateTypes.h"
 #include "cmStringAlgorithms.h"
 #include "cmTarget.h"
@@ -319,6 +320,9 @@ cmComputeLinkDepends::Compute()
   // Follow the link dependencies of the target to be linked.
   this->AddDirectLinkEntries();
 
+  // Add dependencies on targets named by $<TARGET_OBJECTS:...> sources.
+  this->AddTargetObjectEntries();
+
   // Complete the breadth-first search of dependencies.
   while (!this->BFSQueue.empty()) {
     // Get the next entry.
@@ -701,6 +705,21 @@ void cmComputeLinkDepends::AddDirectLinkEntries()
   }
 }
 
+void cmComputeLinkDepends::AddTargetObjectEntries()
+{
+  std::vector<cmSourceFile const*> externalObjects;
+  this->Target->GetExternalObjects(externalObjects, this->Config);
+  for (auto const* externalObject : externalObjects) {
+    std::string const& objLib = externalObject->GetObjectLibrary();
+    if (objLib.empty()) {
+      continue;
+    }
+    cmLinkItem const& objItem =
+      this->Target->ResolveLinkItem(BT<std::string>(objLib));
+    this->AddLinkObject(objItem);
+  }
+}
+
 template <typename T>
 void cmComputeLinkDepends::AddLinkEntries(size_t depender_index,
                                           std::vector<T> const& libs)