DPCT1132

Intel® DPC++ Compatibility Tool Developer Guide and Reference

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ID 768918

Date 10/31/2024

Version

Public

Visible to Intel only — GUID: GUID-80830130-63CA-4C6A-8126-B19FA35EA1F4

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DPCT1132

Message

SYCL 2020 does not support accessing the <property name> for the kernel. The API is replaced with member variable “<variable name>”. Please set the appropriate value for “<variable name>”.

Detailed Help

There is limited support for querying the kernel attribute such as shared memory or number of registers used by a kernel in SYCL* 2020. The tool migrates the following attributes to member variables of a class defined in the DPCT namespace helper function, in order to ensure the compilability of migrated code.

Shared-memory size per-block required by the kernel
Local memory size used by each thread in the kernel
Constant memory size required by the kernel
Number of registers used by each thread in the kernel

It is recommend to use an appropriate value to replace the member variable access, provided it is statically available. Otherwise, consider removing the code along with the part that depends on it.

Suggestions to Fix

For example, this original CUDA* code:

void foo(CUfunction f) {
  int smsize;
  int lcsize;
  int cnsize;
  int nreg;

  cuFuncGetAttribute(&smsize, CU_FUNC_ATTRIBUTE_SHARED_SIZE_BYTES, f);

  cuFuncGetAttribute(&lcsize, CU_FUNC_ATTRIBUTE_LOCAL_SIZE_BYTES, f);

  cuFuncGetAttribute(&cnsize, CU_FUNC_ATTRIBUTE_CONST_SIZE_BYTES, f);

  cuFuncGetAttribute(&nreg, CU_FUNC_ATTRIBUTE_NUM_REGS, f);
}

results in the following migrated SYCL code:

void foo(dpct::kernel_function f) {
  int smsize;
  int lcsize;
  int cnsize;
  int nreg;
  /*
  DPCT1132:0: SYCL 2020 does not support accessing the statically allocated
  shared memory for the kernel. The API is replaced with member variable
  "shared_size_bytes". Please set the appropriate value for "shared_size_bytes".
  */
  smsize = dpct::get_kernel_function_info(f)
               .shared_size_bytes /* statically allocated shared memory per
                                     work-group in bytes */
      ;

  /*
  DPCT1132:1: SYCL 2020 does not support accessing the local memory for the
  kernel. The API is replaced with member variable "local_size_bytes". Please
  set the appropriate value for "local_size_bytes".
  */
  lcsize = dpct::get_kernel_function_info(f)
               .local_size_bytes /* local memory per work-item in bytes */;

  /*
  DPCT1132:2: SYCL 2020 does not support accessing the memory size of
  user-defined constants for the kernel. The API is replaced with member
  variable "const_size_bytes". Please set the appropriate value for
  "const_size_bytes".
  */
  cnsize =
      dpct::get_kernel_function_info(f)
          .const_size_bytes /* user-defined constant kernel memory in bytes */;

  /*
  DPCT1132:3: SYCL 2020 does not support accessing the required number of
  registers for the kernel. The API is replaced with member variable
  "num_regs". Please set the appropriate value for "num_regs".
  */
  nreg = dpct::get_kernel_function_info(f)
             .num_regs /* number of registers for each thread */;
}

which is rewritten to:

void foo(dpct::kernel_function f) {
  int smsize;
  int lcsize;
  int cnsize;
  int nreg;

  smsize = 1024 /* statically allocated shared memory per-group in bytes according
  to kernel function f */;

  lcsize = 1024 /* local memory per work-item in bytes according to kernel function
  f */;

  cnsize = 1024 /* user-defined constant kernel memory in bytes according to kernel
  function f */;

  nreg = 4 /* number of registers for each thread according to kernel function f */;
}

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Intel® DPC++ Compatibility Tool Developer Guide and Reference

DPCT1132

Message

Detailed Help

Suggestions to Fix