CUDA: Fix crash on linking to a CUDA target without CUDA enabled

Do not try to device link or add CUDA runtime libraries if the language
is not enabled.

Fixes: #18673
Issue: #18614

Source/cmMakefileExecutableTargetGenerator.cxx

@@ -84,6 +84,10 @@ void cmMakefileExecutableTargetGenerator::WriteDeviceExecutableRule(
   bool relink)
 {
 #ifdef CMAKE_BUILD_WITH_CMAKE
+  if (!this->GlobalGenerator->GetLanguageEnabled("CUDA")) {
+    return;
+  }
+
   const std::string cuda_lang("CUDA");
   cmGeneratorTarget::LinkClosure const* closure =
     this->GeneratorTarget->GetLinkClosure(this->ConfigName);

Source/cmNinjaNormalTargetGenerator.cxx

@@ -558,6 +558,10 @@ std::vector<std::string> cmNinjaNormalTargetGenerator::ComputeLinkCmd()
 
 void cmNinjaNormalTargetGenerator::WriteDeviceLinkStatement()
 {
+  if (!this->GetGlobalGenerator()->GetLanguageEnabled("CUDA")) {
+    return;
+  }
+
   cmGeneratorTarget& genTarget = *this->GetGeneratorTarget();
 
   // determine if we need to do any device linking for this target

Source/cmVisualStudio10TargetGenerator.cxx

@@ -3331,7 +3331,8 @@ bool cmVisualStudio10TargetGenerator::ComputeLinkOptions(
   std::vector<std::string> vsTargetVec;
   this->AddLibraries(cli, libVec, vsTargetVec, config);
   if (std::find(linkClosure->Languages.begin(), linkClosure->Languages.end(),
-                "CUDA") != linkClosure->Languages.end()) {
+                "CUDA") != linkClosure->Languages.end() &&
+      this->CudaOptions[config] != nullptr) {
     switch (this->CudaOptions[config]->GetCudaRuntime()) {
       case cmVisualStudioGeneratorOptions::CudaRuntimeStatic:
         libVec.push_back("cudadevrt.lib");

Tests/RunCMake/Languages/ExternalCUDA.cmake

@@ -0,0 +1,8 @@
+enable_language(C)
+
+add_library(ext_cuda IMPORTED STATIC)
+set_property(TARGET ext_cuda PROPERTY IMPORTED_LOCATION "/does_not_exist")
+set_property(TARGET ext_cuda PROPERTY IMPORTED_LINK_INTERFACE_LANGUAGES "CUDA")
+
+add_executable(main empty.c)
+target_link_libraries(main ext_cuda)

Tests/RunCMake/Languages/RunCMakeTest.cmake

@@ -6,3 +6,5 @@ run_cmake(link-libraries-TARGET_FILE-genex)
 run_cmake(link-libraries-TARGET_FILE-genex-ok)
 
 run_cmake(DetermineFail)
+
+run_cmake(ExternalCUDA)