fix collective helper (#46582)

paddle/fluid/platform/collective_helper.cc

@@ -73,6 +73,11 @@ class NCCLCommImpl : public NCCLComm {
   std::shared_ptr<platform::CudaEventObject> comm_event_;
 };
 
+NCCLCommContext& NCCLCommContext::Instance() {
+  static NCCLCommContext comm_ctx;
+  return comm_ctx;
+}
+
 NCCLComm* NCCLCommContext::CreateComm(
     ncclUniqueId* nccl_id, int nranks, int rank, int dev_id, int ring_id) {
   PADDLE_ENFORCE_NOT_NULL(nccl_id,

paddle/fluid/platform/collective_helper.h

@@ -69,10 +69,7 @@ class NCCLComm {
 // A singleton NCCL communicator context reserves communication ring ids
 class NCCLCommContext {
  public:
-  static NCCLCommContext& Instance() {
-    static NCCLCommContext comm_ctx;
-    return comm_ctx;
-  }
+  static NCCLCommContext& Instance();
 
   NCCLComm* CreateComm(
       ncclUniqueId* nccl_id, int nranks, int rank, int dev_id, int ring_id = 0);