CUDA: Do not device link if CUDA is not an enabled language

Checks added in commit 81b4d10d8f (CUDA: More exhaustive checks to
determine when to do device linking, 2019-05-09, v3.15.0-rc1~82^2)
assumed that CUDA properties would be set only if CUDA is enabled.

We cannot do a device link step if we do not have the CUDA language
enabled.  This was discovered as some projects unconditionally set CUDA
properties such as `CUDA_RESOLVE_DEVICE_SYMBOLS` even when the CUDA
language has not been enabled.

Fixes: #19432

Source/cmLinkLineDeviceComputer.cxx

@@ -12,6 +12,7 @@
 #include "cmAlgorithms.h"
 #include "cmComputeLinkInformation.h"
 #include "cmGeneratorTarget.h"
+#include "cmGlobalGenerator.h"
 #include "cmLocalGenerator.h"
 #include "cmStateDirectory.h"
 #include "cmStateSnapshot.h"
@@ -142,6 +143,9 @@ std::string cmLinkLineDeviceComputer::GetLinkerLanguage(cmGeneratorTarget*,
 bool requireDeviceLinking(cmGeneratorTarget& target, cmLocalGenerator& lg,
                           const std::string& config)
 {
+  if (!target.GetGlobalGenerator()->GetLanguageEnabled("CUDA")) {
+    return false;
+  }
 
   if (target.GetType() == cmStateEnums::OBJECT_LIBRARY) {
     return false;

Source/cmMakefileExecutableTargetGenerator.cxx

@@ -82,11 +82,7 @@ void cmMakefileExecutableTargetGenerator::WriteDeviceExecutableRule(
   bool relink)
 {
 #ifdef CMAKE_BUILD_WITH_CMAKE
-  if (!this->GlobalGenerator->GetLanguageEnabled("CUDA")) {
-    return;
-  }
-
-  bool requiresDeviceLinking = requireDeviceLinking(
+  const bool requiresDeviceLinking = requireDeviceLinking(
     *this->GeneratorTarget, *this->LocalGenerator, this->ConfigName);
   if (!requiresDeviceLinking) {
     return;

Source/cmMakefileLibraryTargetGenerator.cxx

@@ -123,8 +123,7 @@ void cmMakefileLibraryTargetGenerator::WriteObjectLibraryRules()
 
 void cmMakefileLibraryTargetGenerator::WriteStaticLibraryRules()
 {
-
-  bool requiresDeviceLinking = requireDeviceLinking(
+  const bool requiresDeviceLinking = requireDeviceLinking(
     *this->GeneratorTarget, *this->LocalGenerator, this->ConfigName);
   if (requiresDeviceLinking) {
     std::string linkRuleVar = "CMAKE_CUDA_DEVICE_LINK_LIBRARY";
@@ -152,7 +151,7 @@ void cmMakefileLibraryTargetGenerator::WriteSharedLibraryRules(bool relink)
   }
 
   if (!relink) {
-    bool requiresDeviceLinking = requireDeviceLinking(
+    const bool requiresDeviceLinking = requireDeviceLinking(
       *this->GeneratorTarget, *this->LocalGenerator, this->ConfigName);
     if (requiresDeviceLinking) {
       std::string linkRuleVar = "CMAKE_CUDA_DEVICE_LINK_LIBRARY";
@@ -186,9 +185,8 @@ void cmMakefileLibraryTargetGenerator::WriteSharedLibraryRules(bool relink)
 
 void cmMakefileLibraryTargetGenerator::WriteModuleLibraryRules(bool relink)
 {
-
   if (!relink) {
-    bool requiresDeviceLinking = requireDeviceLinking(
+    const bool requiresDeviceLinking = requireDeviceLinking(
       *this->GeneratorTarget, *this->LocalGenerator, this->ConfigName);
     if (requiresDeviceLinking) {
       std::string linkRuleVar = "CMAKE_CUDA_DEVICE_LINK_LIBRARY";

Source/cmVisualStudio10TargetGenerator.cxx

@@ -3059,7 +3059,7 @@ bool cmVisualStudio10TargetGenerator::ComputeCudaLinkOptions(
   Options& cudaLinkOptions = *pOptions;
 
   // Determine if we need to do a device link
-  bool doDeviceLinking = requireDeviceLinking(
+  const bool doDeviceLinking = requireDeviceLinking(
     *this->GeneratorTarget, *this->LocalGenerator, configName);
 
   cudaLinkOptions.AddFlag("PerformDeviceLink",

Tests/Cuda/CMakeLists.txt

@@ -3,6 +3,7 @@ ADD_TEST_MACRO(Cuda.Complex CudaComplex)
 ADD_TEST_MACRO(Cuda.ConsumeCompileFeatures CudaConsumeCompileFeatures)
 ADD_TEST_MACRO(Cuda.ObjectLibrary CudaObjectLibrary)
 ADD_TEST_MACRO(Cuda.MixedStandardLevels MixedStandardLevels)
+ADD_TEST_MACRO(Cuda.NotEnabled CudaNotEnabled)
 ADD_TEST_MACRO(Cuda.ToolkitInclude CudaToolkitInclude)
 ADD_TEST_MACRO(Cuda.ProperDeviceLibraries ProperDeviceLibraries)
 ADD_TEST_MACRO(Cuda.ProperLinkFlags ProperLinkFlags)

Tests/Cuda/NotEnabled/CMakeLists.txt

@@ -0,0 +1,14 @@
+cmake_minimum_required(VERSION 3.7)
+project(CudaNotEnabled CXX)
+
+add_library(HasCudaProps lib.cxx)
+
+target_compile_features(HasCudaProps PUBLIC cxx_std_11)
+#Verify that setting this variables in a project that doesn't have CUDA
+#enabled allow for the project to configure and build correctly.
+#Tests the fix for #19432
+set_property(TARGET HasCudaProps PROPERTY CUDA_SEPARABLE_COMPILATION ON)
+set_property(TARGET HasCudaProps PROPERTY CUDA_RESOLVE_DEVICE_SYMBOLS ON)
+
+add_executable(CudaNotEnabled main.cxx)
+target_link_libraries(CudaNotEnabled PRIVATE HasCudaProps)

Tests/Cuda/NotEnabled/lib.cxx

@@ -0,0 +1,5 @@
+
+int cxx_function(int input)
+{
+  return input;
+}

Tests/Cuda/NotEnabled/main.cxx

@@ -0,0 +1,9 @@
+
+#include <type_traits>
+
+int main(int argc, char** argv)
+{
+  // make sure we have c++11 enabled
+  using returnv = std::integral_constant<int, 0>;
+  return returnv::value;
+}