[REFACTOR][FFI] Make more clear naming for C API Type codes. (apache#…

…4715)

This PR introduces more clear naming prefix for C API type codes
to avoid conflict with other packages.

We also removed TVMArray and TVMType to directly use DLTensor and DLDataType.

src/device_api.cc

@@ -45,7 +45,7 @@ class VTADeviceAPI final : public DeviceAPI {
   void* AllocDataSpace(TVMContext ctx,
                        size_t size,
                        size_t alignment,
-                       TVMType type_hint) final {
+                       DLDataType type_hint) final {
     return VTABufferAlloc(size);
   }
 
@@ -60,7 +60,7 @@ class VTADeviceAPI final : public DeviceAPI {
                       size_t size,
                       TVMContext ctx_from,
                       TVMContext ctx_to,
-                      TVMType type_hint,
+                      DLDataType type_hint,
                       TVMStreamHandle stream) final {
     int kind_mask = 0;
     if (ctx_from.device_type != kDLCPU) {
@@ -77,7 +77,7 @@ class VTADeviceAPI final : public DeviceAPI {
   void StreamSync(TVMContext ctx, TVMStreamHandle stream) final {
   }
 
-  void* AllocWorkspace(TVMContext ctx, size_t size, TVMType type_hint) final;
+  void* AllocWorkspace(TVMContext ctx, size_t size, DLDataType type_hint) final;
 
   void FreeWorkspace(TVMContext ctx, void* data) final;
 
@@ -93,7 +93,7 @@ struct VTAWorkspacePool : public WorkspacePool {
       WorkspacePool(kDLExtDev, VTADeviceAPI::Global()) {}
 };
 
-void* VTADeviceAPI::AllocWorkspace(TVMContext ctx, size_t size, TVMType type_hint) {
+void* VTADeviceAPI::AllocWorkspace(TVMContext ctx, size_t size, DLDataType type_hint) {
   return dmlc::ThreadLocalStore<VTAWorkspacePool>::Get()
       ->AllocWorkspace(ctx, size);
 }