fix(tree): move declarations to top of function

c++ suppoorts initializers anywhere in the function, but one must not
jump over an initializer with any goto usage. Given the lack of RAII in
C, this becomes a significant painpoint.

In large to-be-eventually-refactored functions contain gotos or use
switch statements, split declaration and initialization, and move all
declarations to the top of the function. This makes switch statements
and gotos safe in both languages.

stack-info: PR: #563, branch: aws-nslick/stack/10
Signed-off-by: Nicholas Sielicki <nslick@amazon.com>

src/nccl_ofi_api.c

@@ -318,15 +318,16 @@ ncclResult_t nccl_net_ofi_regMr(void *comm, void *data, size_t size, int type,
 		return ncclInternalError;
 	}
 
+	nccl_net_ofi_send_comm_t *send_comm = NULL;
+	nccl_net_ofi_recv_comm_t *recv_comm = NULL;
+
 	switch (base_comm->type) {
-	case NCCL_NET_OFI_SEND_COMM:;
-		nccl_net_ofi_send_comm_t *send_comm =
-			(nccl_net_ofi_send_comm_t *)base_comm;
+	case NCCL_NET_OFI_SEND_COMM:
+		send_comm = (nccl_net_ofi_send_comm_t *)base_comm;
 		ret = send_comm->regMr(send_comm, data, size, type, mhandle);
 		break;
-	case NCCL_NET_OFI_RECV_COMM:;
-		nccl_net_ofi_recv_comm_t *recv_comm =
-			(nccl_net_ofi_recv_comm_t *)base_comm;
+	case NCCL_NET_OFI_RECV_COMM:
+		recv_comm = (nccl_net_ofi_recv_comm_t *)base_comm;
 		ret = recv_comm->regMr(recv_comm, data, size, type, mhandle);
 		break;
 	default:
@@ -350,16 +351,16 @@ ncclResult_t nccl_net_ofi_deregMr(void *comm, void *mhandle)
 	}
 
 	int ret = 0;
+	nccl_net_ofi_send_comm_t *send_comm = NULL;
+	nccl_net_ofi_recv_comm_t *recv_comm = NULL;
 
 	switch (base_comm->type) {
-	case NCCL_NET_OFI_SEND_COMM:;
-		nccl_net_ofi_send_comm_t *send_comm =
-			(nccl_net_ofi_send_comm_t *)base_comm;
+	case NCCL_NET_OFI_SEND_COMM:
+		send_comm = (nccl_net_ofi_send_comm_t *)base_comm;
 		ret = send_comm->deregMr(send_comm, (nccl_net_ofi_mr_handle_t *)mhandle);
 		break;
-	case NCCL_NET_OFI_RECV_COMM:;
-		nccl_net_ofi_recv_comm_t *recv_comm =
-			(nccl_net_ofi_recv_comm_t *)base_comm;
+	case NCCL_NET_OFI_RECV_COMM:
+		recv_comm = (nccl_net_ofi_recv_comm_t *)base_comm;
 		ret = recv_comm->deregMr(recv_comm, (nccl_net_ofi_mr_handle_t *)mhandle);
 		break;
 	default:
@@ -386,17 +387,17 @@ ncclResult_t nccl_net_ofi_regMrDmaBuf(void* comm, void* data, size_t size,
 	}
 
 	int ret = 0;
+	nccl_net_ofi_send_comm_t *send_comm = NULL;
+	nccl_net_ofi_recv_comm_t *recv_comm = NULL;
 	nccl_net_ofi_mr_handle_t **handle = (nccl_net_ofi_mr_handle_t **)mhandle;
 
 	switch (base_comm->type) {
-	case NCCL_NET_OFI_SEND_COMM:;
-		nccl_net_ofi_send_comm_t *send_comm =
-			(nccl_net_ofi_send_comm_t *)base_comm;
+	case NCCL_NET_OFI_SEND_COMM:
+		send_comm = (nccl_net_ofi_send_comm_t *)base_comm;
 		ret = send_comm->regMrDmaBuf(send_comm, data, size, type, offset, fd, handle);
 		break;
-	case NCCL_NET_OFI_RECV_COMM:;
-		nccl_net_ofi_recv_comm_t *recv_comm =
-			(nccl_net_ofi_recv_comm_t *)base_comm;
+	case NCCL_NET_OFI_RECV_COMM:
+		recv_comm = (nccl_net_ofi_recv_comm_t *)base_comm;
 		ret = recv_comm->regMrDmaBuf(recv_comm, data, size, type, offset, fd, handle);
 		break;
 	default:

src/nccl_ofi_ep_addr_list.c

@@ -134,6 +134,7 @@ int nccl_ofi_ep_addr_list_insert(nccl_ofi_ep_addr_list_t *ep_list,
 				 size_t addr_size)
 {
 	int ret = 0;
+	ep_pair_list_elem_t *new_pair = NULL;
 
 	if (addr_size > ep_list->max_addr_size) {
 		NCCL_OFI_WARN("Address size %zu > max size (%zu)", addr_size,
@@ -155,7 +156,7 @@ int nccl_ofi_ep_addr_list_insert(nccl_ofi_ep_addr_list_t *ep_list,
 	memcpy(new_addr->addr, addr_in, addr_size);
 	zero_pad_address(new_addr->addr, addr_size, ep_list->max_addr_size);
 
-	ep_pair_list_elem_t *new_pair = (ep_pair_list_elem_t *)
+	new_pair = (ep_pair_list_elem_t*)
 		malloc(sizeof(*new_pair));
 	if (!new_pair) {
 		NCCL_OFI_WARN("Failed to allocate new ep list element");

src/nccl_ofi_net.c

@@ -134,6 +134,8 @@ int nccl_net_ofi_create_plugin(nccl_net_ofi_plugin_t **plugin_p)
 {
 	int ret = 0;
 	const char *provider_filter = NULL;
+	nccl_net_ofi_ep_t *base_ep = NULL;
+	nccl_net_ofi_device_t *device = NULL;
 
 	NCCL_OFI_INFO(NCCL_INIT | NCCL_NET, "Initializing " PACKAGE_STRING);
 
@@ -230,8 +232,7 @@ int nccl_net_ofi_create_plugin(nccl_net_ofi_plugin_t **plugin_p)
 	 * resources. This initialization happens once per process, and thus it
 	 * does not matter which device is used to create the endpoint.
 	 */
-	nccl_net_ofi_device_t *device = (*plugin_p)->get_device(*plugin_p, 0);
-	nccl_net_ofi_ep_t *base_ep = NULL;
+	device = (*plugin_p)->get_device(*plugin_p, 0);
 
 	ret = device->get_ep(device, &base_ep);
 	if (ret != 0) {