Merge topic 'nvcc_dlink_dedup_static_libs'

fd0523a215 CUDA: Properly de-duplicate libs when doing device linking
b07c71831c CUDA: Add a test to verify device linking can handle circular deps

Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !2214

Source/cmLinkLineDeviceComputer.cxx

@@ -3,7 +3,9 @@
 
 #include "cmLinkLineDeviceComputer.h"
 
+#include <set>
 #include <sstream>
+#include <utility>
 
 #include "cmAlgorithms.h"
 #include "cmComputeLinkInformation.h"
@@ -28,6 +30,12 @@ std::string cmLinkLineDeviceComputer::ComputeLinkLibraries(
 {
   // Write the library flags to the build rule.
   std::ostringstream fout;
+
+  // Generate the unique set of link items when device linking.
+  // The nvcc device linker is designed so that each static library
+  // with device symbols only needs to be listed once as it doesn't
+  // care about link order.
+  std::set<std::string> emitted;
   typedef cmComputeLinkInformation::ItemVector ItemVector;
   ItemVector const& items = cli.GetItems();
   std::string config = cli.GetConfig();
@@ -50,20 +58,24 @@ std::string cmLinkLineDeviceComputer::ComputeLinkLibraries(
       }
     }
 
+    std::string out;
     if (item.IsPath) {
       // nvcc understands absolute paths to libraries ending in '.a' should
       // be passed to nvlink.  Other extensions like '.so' or '.dylib' are
       // rejected by the nvcc front-end even though nvlink knows to ignore
       // them.  Bypass the front-end via '-Xnvlink'.
       if (!cmHasLiteralSuffix(item.Value, ".a")) {
-        fout << "-Xnvlink ";
+        out += "-Xnvlink ";
       }
-      fout << this->ConvertToOutputFormat(
-        this->ConvertToLinkReference(item.Value));
+      out +=
+        this->ConvertToOutputFormat(this->ConvertToLinkReference(item.Value));
     } else {
-      fout << item.Value;
+      out += item.Value;
+    }
+
+    if (emitted.insert(out).second) {
+      fout << out << " ";
     }
-    fout << " ";
   }
 
   if (!stdLibString.empty()) {