[SYCL][PI][CUDA] Init plugin function table to 0

As the PI plugin function table can grow without the CUDA plugin being
adapted, set the whole function pointer table to 0 to trigger crashes
on calling functions that are not set.

Signed-off-by: Bjoern Knafla <bjoern@codeplay.com>

Author: bjoernknafla

sycl/plugins/cuda/pi_cuda.cpp

@@ -2784,6 +2784,11 @@ pi_result piPluginInit(pi_plugin *PluginInit) {
   // PI interface supports higher version or the same version.
   strncpy(PluginInit->PluginVersion, SupportedVersion, 4);
 
+  // Set whole function table to zero to make it easier to detect if
+  // functions are not set up below.
+  std::memset(&(PluginInit->PiFunctionTable), 0,
+              sizeof(PluginInit->PiFunctionTable));
+
 // Forward calls to OpenCL RT.
 #define _PI_CL(pi_api, cuda_api)                                         \
   (PluginInit->PiFunctionTable).pi_api = (decltype(&::pi_api))(&cuda_api);
@@ -2838,6 +2843,7 @@ pi_result piPluginInit(pi_plugin *PluginInit) {
   _PI_CL(piKernelRetain, cuda_piKernelRetain)
   _PI_CL(piKernelRelease, cuda_piKernelRelease)
   _PI_CL(piKernelSetExecInfo, cuda_piKernelSetExecInfo)
+
   // Event
   _PI_CL(piEventCreate, cuda_piEventCreate)
   _PI_CL(piEventGetInfo, cuda_piEventGetInfo)
@@ -2869,6 +2875,7 @@ pi_result piPluginInit(pi_plugin *PluginInit) {
   _PI_CL(piEnqueueMemImageFill, cuda_piEnqueueMemImageFill)
   _PI_CL(piEnqueueMemBufferMap, cuda_piEnqueueMemBufferMap)
   _PI_CL(piEnqueueMemUnmap, cuda_piEnqueueMemUnmap)
+
   _PI_CL(piextKernelSetArgMemObj, cuda_piextKernelSetArgMemObj)
 
 #undef _PI_CL