GpuKernelFunction

A procedure that runs on a GPU.

Declaration

Syntax

GpuKernelFunction(symbol_table symtab, identifier name,
    ttype function_signature, identifier* dependencies, expr* args,
    stmt* body, access access, location start_name, location end_name)

Arguments

Argument

Description

symtab

the symbol table of the kernel: its arguments and its local variables.

name

the name of the kernel.

function_signature

a FunctionType with no return_var_type: a kernel returns nothing.

dependencies

the names of the symbols the body refers to.

args

the arguments of the kernel, as Var expressions.

body

the statements executed by every thread of the kernel.

access

Public or Private.

start_name

the source span of the name in the opening statement.

end_name

the source span of the name in the closing statement.

Return values

None.

Description

A GpuKernelFunction is separate from Function because it is not callable in the ordinary sense: it is launched, with an execution configuration, by GpuKernelLaunch, and it always returns nothing.

Inside the body, the position of the running thread is read with GpuThreadIndex, GpuBlockIndex and GpuBlockSize.

Examples

An ASR text document that uses it:

(TranslationUnit
  :symtab (SymbolTable
    :id 0
    :symbols {
      "m" (Module
        :symtab (SymbolTable
          :id 1
          :symbols {
            "scale" (GpuKernelFunction
              :symtab (SymbolTable
                :id 2
                :symbols {
                  "a" (Variable
                    :parent_symtab 2
                    :name "a"
                    :dependencies []
                    :intent :InOut
                    :symbolic_value nil
                    :value nil
                    :storage :Default
                    :type (Array
                      :type (Real
                        :kind 4
                      )
                      :dims [
                        (dimension
                          :start (IntegerConstant
                            :n 1
                            :type (Integer
                              :kind 4
                            )
                            :intboz_type :Decimal
                          )
                          :length (IntegerConstant
                            :n 256
                            :type (Integer
                              :kind 4
                            )
                            :intboz_type :Decimal
                          )
                        )
                      ]
                      :physical_type :FixedSizeArray
                    )
                    :type_declaration nil
                    :abi :Source
                    :access :Public
                    :presence :Required
                    :value_attr false
                    :target_attr false
                    :contiguous_attr false
                    :bindc_name nil
                    :is_volatile false
                    :is_protected false
                    :pass_attr :NotMethod
                    :self_argument nil
                    :codims []
                  )
                  "i" (Variable
                    :parent_symtab 2
                    :name "i"
                    :dependencies []
                    :intent :Local
                    :symbolic_value nil
                    :value nil
                    :storage :Default
                    :type (Integer
                      :kind 4
                    )
                    :type_declaration nil
                    :abi :Source
                    :access :Public
                    :presence :Required
                    :value_attr false
                    :target_attr false
                    :contiguous_attr false
                    :bindc_name nil
                    :is_volatile false
                    :is_protected false
                    :pass_attr :NotMethod
                    :self_argument nil
                    :codims []
                  )
                }
              )
              :name "scale"
              :function_signature (FunctionType
                :arg_types [
                  (Array
                    :type (Real
                      :kind 4
                    )
                    :dims [
                      (dimension
                        :start (IntegerConstant
                          :n 1
                          :type (Integer
                            :kind 4
                          )
                          :intboz_type :Decimal
                        )
                        :length (IntegerConstant
                          :n 256
                          :type (Integer
                            :kind 4
                          )
                          :intboz_type :Decimal
                        )
                      )
                    ]
                    :physical_type :FixedSizeArray
                  )
                ]
                :return_var_type nil
                :abi :Source
                :deftype :Implementation
                :bindc_name nil
                :elemental false
                :pure false
                :module false
                :inline false
                :static false
                :restrictions []
                :is_restriction false
              )
              :dependencies []
              :args [
                (Var
                  :v (SymbolRef 2 "a")
                )
              ]
              :body [
                (Assignment
                  :target (Var
                    :v (SymbolRef 2 "i")
                  )
                  :value (IntegerBinOp
                    :left (GpuThreadIndex
                      :dim 0
                      :type (Integer
                        :kind 4
                      )
                      :value nil
                    )
                    :op :Add
                    :right (IntegerConstant
                      :n 1
                      :type (Integer
                        :kind 4
                      )
                      :intboz_type :Decimal
                    )
                    :type (Integer
                      :kind 4
                    )
                    :value nil
                  )
                  :overloaded nil
                  :realloc_lhs false
                  :move_allocation false
                )
                (Assignment
                  :target (Var
                    :v (SymbolRef 2 "i")
                  )
                  :value (IntegerBinOp
                    :left (GpuBlockIndex
                      :dim 0
                      :type (Integer
                        :kind 4
                      )
                      :value nil
                    )
                    :op :Mul
                    :right (GpuBlockSize
                      :dim 0
                      :type (Integer
                        :kind 4
                      )
                      :value nil
                    )
                    :type (Integer
                      :kind 4
                    )
                    :value nil
                  )
                  :overloaded nil
                  :realloc_lhs false
                  :move_allocation false
                )
                (Assignment
                  :target (ArrayItem
                    :v (Var
                      :v (SymbolRef 2 "a")
                    )
                    :args [
                      (array_index
                        :left nil
                        :right (Var
                          :v (SymbolRef 2 "i")
                        )
                        :step nil
                      )
                    ]
                    :type (Real
                      :kind 4
                    )
                    :storage_format :ColMajor
                    :value nil
                  )
                  :value (RealConstant
                    :r 0.0
                    :type (Real
                      :kind 4
                    )
                  )
                  :overloaded nil
                  :realloc_lhs false
                  :move_allocation false
                )
              ]
              :access :Public
            )
          }
        )
        :name "m"
        :parent_module nil
        :dependencies []
        :loaded_from_mod false
        :intrinsic false
        :has_submodules false
      )
      "main" (Program
        :symtab (SymbolTable
          :id 3
          :symbols {}
        )
        :name "main"
        :dependencies []
        :body []
      )
    }
  )
  :items []
)

See Also

GpuKernelLaunch, GpuThreadIndex, GpuBlockIndex, Function