[Polly][GPUJIT] Disabled gcc's -Wpedantic for use of dlsym

[PhilippSchaad]

Summary

GCC's ISO C standard does not strictly define the bahavior of converting a void*
pointer to a function pointer, but dlsym's POSIX standard does. The retrieval of function pointers
through dlsym in this case generates an unnecessary amount of warnings for every API function
assignment, bloating the output. Removing GCC's -Wpedantic flag only for the retrieval and
assignment of said functions thus seems like a good idea, simplifying debugging of the GPUJIT
in the future. Agree?

[grosser]

LGTM.

[grosser]

I forgot to add: @bollu, feel free to critically review this regarding better alternatives or to decide to commit it as it is.

[bollu]

Could you please add a reference to the standard either in the code or the commit message? I believe this is the official reference.

[PhilippSchaad]

added reference

polly/trunk/tools/GPURuntime/GPUJIT.c

static int initialDeviceAPILibrariesCL() {
   HandleOpenCL = dlopen("libOpenCL.so", RTLD_LAZY);
   if (!HandleOpenCL) {
     fprintf(stderr, "Cannot open library: %s. \n", dlerror());
     return 0;
   }
   return 1;
 }
 
-static int initialDeviceAPIsCL() {
-  if (initialDeviceAPILibrariesCL() == 0)
-    return 0;
-
-  /* Get function pointer to OpenCL Runtime API.
-   *
-   * Note that compilers conforming to the ISO C standard are required to
-   * generate a warning if a conversion from a void * pointer to a function
-   * pointer is attempted as in the following statements. The warning
-   * of this kind of cast may not be emitted by clang and new versions of gcc
-   * as it is valid on POSIX 2008.
-   */
+ * as it is valid on POSIX 2008. For compilers required to generate a warning,
+ * we temporarily disable -Wpedantic, to avoid bloating the output with
+ * unnecessary warnings.
+ *
+ * Reference:
+ * http://pubs.opengroup.org/onlinepubs/9699919799/functions/dlsym.html
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wpedantic"
+static int initialDeviceAPIsCL() {
+  if (initialDeviceAPILibrariesCL() == 0)
+    return 0;
+
   clGetPlatformIDsFcnPtr =
       (clGetPlatformIDsFcnTy *)getAPIHandleCL(HandleOpenCL, "clGetPlatformIDs");
 
   clGetDeviceIDsFcnPtr =
       (clGetDeviceIDsFcnTy *)getAPIHandleCL(HandleOpenCL, "clGetDeviceIDs");
 
   clGetDeviceInfoFcnPtr =
       (clGetDeviceInfoFcnTy *)getAPIHandleCL(HandleOpenCL, "clGetDeviceInfo");
static int initialDeviceAPIsCL() {
   clReleaseCommandQueueFcnPtr = (clReleaseCommandQueueFcnTy *)getAPIHandleCL(
       HandleOpenCL, "clReleaseCommandQueue");
 
   clReleaseContextFcnPtr =
       (clReleaseContextFcnTy *)getAPIHandleCL(HandleOpenCL, "clReleaseContext");
 
   return 1;
 }
+#pragma GCC diagnostic pop
 
 /* Context and Device. */
 static PollyGPUContext *GlobalContext = NULL;
 static cl_device_id GlobalDeviceID = NULL;
 
 /* Fd-Decl: Print out OpenCL Error codes to human readable strings. */
 static void printOpenCLError(int Error);
 
static int initialDeviceAPILibrariesCUDA() {
   if (!HandleCudaRT) {
     fprintf(stderr, "Cannot open library: %s. \n", dlerror());
     return 0;
   }
 
   return 1;
 }
 
-static int initialDeviceAPIsCUDA() {
-  if (initialDeviceAPILibrariesCUDA() == 0)
-    return 0;
-
-  /* Get function pointer to CUDA Driver APIs.
-   *
-   * Note that compilers conforming to the ISO C standard are required to
-   * generate a warning if a conversion from a void * pointer to a function
-   * pointer is attempted as in the following statements. The warning
-   * of this kind of cast may not be emitted by clang and new versions of gcc
-   * as it is valid on POSIX 2008.
-   */
+ * as it is valid on POSIX 2008. For compilers required to generate a warning,
+ * we temporarily disable -Wpedantic, to avoid bloating the output with
+ * unnecessary warnings.
+ *
+ * Reference:
+ * http://pubs.opengroup.org/onlinepubs/9699919799/functions/dlsym.html
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wpedantic"
+static int initialDeviceAPIsCUDA() {
+  if (initialDeviceAPILibrariesCUDA() == 0)
+    return 0;
+
   CuLaunchKernelFcnPtr =
       (CuLaunchKernelFcnTy *)getAPIHandleCUDA(HandleCuda, "cuLaunchKernel");
 
   CuMemAllocFcnPtr =
       (CuMemAllocFcnTy *)getAPIHandleCUDA(HandleCuda, "cuMemAlloc_v2");
 
   CuMemFreeFcnPtr =
       (CuMemFreeFcnTy *)getAPIHandleCUDA(HandleCuda, "cuMemFree_v2");
CuCtxSynchronizeFcnPtr =
       (CuCtxSynchronizeFcnTy *)getAPIHandleCUDA(HandleCuda, "cuCtxSynchronize");
 
   /* Get function pointer to CUDA Runtime APIs. */
   CudaThreadSynchronizeFcnPtr = (CudaThreadSynchronizeFcnTy *)getAPIHandleCUDA(
       HandleCudaRT, "cudaThreadSynchronize");
 
   return 1;
 }
+#pragma GCC diagnostic pop
 
 static PollyGPUContext *initContextCUDA() {
   dump_function();
   PollyGPUContext *Context;
   CUdevice Device;
 
   int Major = 0, Minor = 0, DeviceID = 0;
   char DeviceName[256];