clBuildProgram

Builds (compiles and links) a program executable from the program source or binary.

cl_int clBuildProgram ( cl_program program,
  cl_uint num_devices,
  const cl_device_id *device_list,
  const char *options,
  void (CL_CALLBACK *pfn_notify)(cl_program program, void *user_data),
  void *user_data)

Parameters

program

The program object.

device_list

A pointer to a list of devices associated with program. If device_list is NULL value, the program executable is built for all devices associated with program for which a source or binary has been loaded. If device_list is a non-NULL value, the program executable is built for devices specified in this list for which a source or binary has been loaded.

num_devices

The number of devices listed in device_list.

options

A pointer to a null-terminated string of characters that describes the build options to be used for building the program executable. The list of supported options is described below.

pfn_notify

A function pointer to a notification routine. The notification routine is a callback function that an application can register and which will be called when the program executable has been built (successfully or unsuccessfully). If pfn_notify is not NULL, clBuildProgram does not need to wait for the build to complete and can return immediately once the build operation can begin. The build operation can begin if the context, program whose sources are being compiled and linked, list of devices and build options specified are all valid and appropriate host and device resources needed to perform the build are available. If pfn_notify is NULL, clBuildProgram does not return until the build has completed. This callback function may be called asynchronously by the OpenCL implementation. It is the application’s responsibility to ensure that the callback function is thread-safe.

user_data

Passed as an argument when pfn_notify is called. user_data can be NULL.

Notes

Builds (compiles & links) a program executable from the program source or binary for all the devices or a specific device(s) in the OpenCL context associated with program. OpenCL allows program executables to be built using the source or the binary. clBuildProgram must be called for program created using either clCreateProgramWithSource or clCreateProgramWithBinary to build the program executable for one or more devices associated with program. If program is created with clCreateProgramWithBinary, then the program binary must be an executable binary (not a compiled binary or library).

The executable binary can be queried using clGetProgramInfo(program, CL_PROGRAM_BINARIES, ...) and can be specified to clCreateProgramWithBinary to create a new program object.

Compiler Options

The compiler options are categorized as pre-processor options, options for math intrinsics, options that control optimization and miscellaneous options. This specification defines a standard set of options that must be supported by the OpenCL C compiler when building program executables online or offline. These may be extended by a set of vendor- or platform specific options.

Preprocessor Options

These options control the OpenCL C preprocessor which is run on each program source before actual compilation.

-D options are processed in the order they are given in the options argument to clBuildProgram or or clCompileProgram.

-D name

Predefine name as a macro, with definition 1.

-D name=definition

The contents of definition are tokenized and processed as if they appeared during translation phase three in a `#define' directive. In particular, the definition will be truncated by embedded newline characters.

-I dir

Add the directory dir to the list of directories to be searched for header files.

Math Intrinsics Options

These options control compiler behavior regarding floating-point arithmetic. These options trade off between speed and correctness.
-cl-single-precision-constant

Treat double precision floating-point constant as single precision constant.

-cl-denorms-are-zero

This option controls how single precision and double precision denormalized numbers are handled. If specified as a build option, the single precision denormalized numbers may be flushed to zero; double precision denormalized numbers may also be flushed to zero if the optional extension for double precsion is supported. This is intended to be a performance hint and the OpenCL compiler can choose not to flush denorms to zero if the device supports single precision (or double precision) denormalized numbers.

This option is ignored for single precision numbers if the device does not support single precision denormalized numbers i.e. CL_FP_DENORM bit is not set in CL_DEVICE_SINGLE_FP_CONFIG.

This option is ignored for double precision numbers if the device does not support double precision or if it does support double precison but CL_FP_DENORM bit is not set in CL_DEVICE_DOUBLE_FP_CONFIG.

This flag only applies for scalar and vector single precision floating-point variables and computations on these floating-point variables inside a program. It does not apply to reading from or writing to image objects.

-cl-fp32-correctly-rounded-divide-sqrt

The -cl-fp32-correctly-rounded-divide-sqrt build option to clBuildProgram or clCompileProgram allows an application to specify that single precision floating-point divide (x/y and 1/x) and sqrt used in the program source are correctly rounded. If this build option is not specified, the minimum numerical accuracy of single precision floating-point divide and sqrt are as defined in section 7.4 of the OpenCL specification.

This build option can only be specified if the CL_FP_CORRECTLY_ROUNDED_DIVIDE_SQRT is set in CL_DEVICE_SINGLE_FP_CONFIG (as defined in in the table of allowed values for param_name for clGetDeviceInfo) for devices that the program is being build. clBuildProgram or clCompileProgram will fail to compile the program for a device if the -cl-fp32-correctly-rounded-divide-sqrt option is specified and CL_FP_CORRECTLY_ROUNDED_DIVIDE_SQRT is not set for the device.

Optimization Options

These options control various sorts of optimizations. Turning on optimization flags makes the compiler attempt to improve the performance and/or code size at the expense of compilation time and possibly the ability to debug the program.

-cl-opt-disable

This option disables all optimizations. The default is optimizations are enabled.

The following options control compiler behavior regarding floating-point arithmetic. These options trade off between performance and correctness and must be specifically enabled. These options are not turned on by default since it can result in incorrect output for programs which depend on an exact implementation of IEEE 754 rules/specifications for math functions.

-cl-mad-enable

Allow a * b + c to be replaced by a mad. The mad computes a * b + c with reduced accuracy. For example, some OpenCL devices implement mad as truncate the result of a * b before adding it to c.

-cl-no-signed-zeros

Allow optimizations for floating-point arithmetic that ignore the signedness of zero. IEEE 754 arithmetic specifies the distinct behavior of +0.0 and -0.0 values, which then prohibits simplification of expressions such as x+0.0 or 0.0*x (even with -clfinite-math only). This option implies that the sign of a zero result isn't significant.

-cl-unsafe-math-optimizations

Allow optimizations for floating-point arithmetic that (a) assume that arguments and results are valid, (b) may violate IEEE 754 standard and (c) may violate the OpenCL numerical compliance requirements as defined in section 7.4 for single precision and double precision floating-point, and edge case behavior in section 7.5. This option includes the -cl-no-signed-zeros and -cl-mad-enable options.

-cl-finite-math-only

Allow optimizations for floating-point arithmetic that assume that arguments and results are not NaNs or ±∞. This option may violate the OpenCL numerical compliance requirements defined in section 7.4 for single precision and double precision floating point, and edge case behavior in section 7.5.

-cl-fast-relaxed-math

Sets the optimization options -cl-finite-math-only and -cl-unsafe-math-optimizations. This allows optimizations for floating-point arithmetic that may violate the IEEE 754 standard and the OpenCL numerical compliance requirements defined in the specification in section 7.4 for single-precision and double precision floating-point, and edge case behavior in section 7.5. This option causes the preprocessor macro __FAST_RELAXED_MATH__ to be defined in the OpenCL program.

Options to Request or Suppress Warnings

Warnings are diagnostic messages that report constructions which are not inherently erroneous but which are risky or suggest there may have been an error. The following languageindependent options do not enable specific warnings but control the kinds of diagnostics produced by the OpenCL compiler.
-w

Inhibit all warning messages.

-Werror

Make all warnings into errors.

Options Controlling the OpenCL C Version

The following option controls the version of OpenCL C that the compiler accepts.
-cl-std=

Determine the OpenCL C language version to use. A value for this option must be provided. Valid values are:

CL1.1 - Support all OpenCL C programs that use the OpenCL C language features defined in section 6 of the OpenCL 1.1 specification.

CL1.2 – Support all OpenCL C programs that use the OpenCL C language features defined in section 6 of the OpenCL 1.2 specification.

Calls to clBuildProgram or clCompileProgram with the -cl-std=CL1.1 option will fail to compile the program for any devices with CL_DEVICE_OPENCL_C_VERSION = OpenCL C 1.0. Calls to clBuildProgram or clCompileProgram with the -cl-std=CL1.2 option will fail to compile the program for any devices with CL_DEVICE_OPENCL_C_VERSION = OpenCL C 1.0 or OpenCL C 1.1.

If the -cl-std build option is not specified, the CL_DEVICE_OPENCL_C_VERSION is used to select the version of OpenCL C to be used when compiling the program for each device.

Options for Querying Kernel Argument Information

-cl-kernel-arg-info

This option allows the compiler to store information about the arguments of a kernel(s) in the program executable. The argument information stored includes the argument name, its type, the address and access qualifiers used. Refer to description of clGetKernelArgInfo on how to query this information.

Linker Options

This specification defines a standard set of linker options that must be supported by the OpenCL C compiler when linking compiled programs online or offline. These linker options are categorized as library linking options and program linking options. These may be extended by a set of vendor- or platform-specific options.

Library Linking Options

The following options can be specified when creating a library of compiled binaries.
-create-library

Create a library of compiled binaries specified in input_programs argument to clLinkProgram.

-enable-link-options

Allows the linker to modify the library behavior based on one or more link options (described in Program Linking Options, below) when this library is linked with a program executable. This option must be specified with the –create-library option.

Program Linking Options

The following options can be specified when linking a program executable.
  • -cl-denorms-are-zero
  • -cl-no-signed-zeroes
  • -cl-unsafe-math-optimizations
  • -cl-finite-math-only
  • -cl-fast-relaxed-mat
The linker may apply these options to all compiled program objects specified to clLinkProgram. The linker may apply these options only to libraries which were created with the –enable-link-option.

Separate Compilation and Linking of Programs

OpenCL 1.2 extends how programs are compiled and linked to support the following:

  • Separate compilation and link stages. Program sources can be compiled to generate a compiled binary object and linked in a separate stage with other compiled program objects to the program exectuable.
  • Embedded headers. In OpenCL 1.0 and 1.1, the –I build option could be used to specify the list of directories to be searched for headers files that are included by a program source(s). OpenCL 1.2 extends this by allowing the header sources to come from program objects instead of just header files.
  • Libraries. The linker can be used to link compiled objects and libraries into a program executable or to create a library of compiled binarie

Errors

clBuildProgram returns CL_SUCCESS if the function is executed successfully. Otherwise, it returns one of the following errors:

  • CL_INVALID_PROGRAM if program is not a valid program object.
  • CL_INVALID_VALUE if device_list is NULL and num_devices is greater than zero, or if device_list is not NULL and num_devices is zero.
  • CL_INVALID_VALUE if pfn_notify is NULL but user_data is not NULL.
  • CL_INVALID_DEVICE if OpenCL devices listed in device_list are not in the list of devices associated with program.
  • CL_INVALID_BINARY if program is created with clCreateProgramWithBinary and devices listed in device_list do not have a valid program binary loaded.
  • CL_INVALID_BUILD_OPTIONS if the build options specified by options are invalid.
  • CL_INVALID_OPERATION if the build of a program executable for any of the devices listed in device_list by a previous call to clBuildProgram for program has not completed.
  • CL_COMPILER_NOT_AVAILABLE if program is created with clCreateProgramWithSource and a compiler is not available i.e. CL_DEVICE_COMPILER_AVAILABLE specified in the table of OpenCL Device Queries for clGetDeviceInfo is set to CL_FALSE.
  • CL_BUILD_PROGRAM_FAILURE if there is a failure to build the program executable. This error will be returned if clBuildProgram does not return until the build has completed.
  • CL_INVALID_OPERATION if there are kernel objects attached to program.
  • CL_INVALID_OPERATION if program was not created with clCreateProgramWithSource or clCreateProgramWithBinary.
  • CL_OUT_OF_RESOURCES if there is a failure to allocate resources required by the OpenCL implementation on the device.
  • CL_OUT_OF_HOST_MEMORY if there is a failure to allocate resources required by the OpenCL implementation on the host.

Specification

OpenCL Specification

Also see

clGetDeviceInfo

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