Add OpenCL extension and buildkite CI

.buildkite/pipeline.yml

@@ -56,3 +56,22 @@ steps:
       intel: "*"
     if: build.message !~ /\[skip tests\]/
     timeout_in_minutes: 15
+
+  - label: "OpenCL.jl"
+    plugins:
+      - JuliaCI/julia#v1:
+          version: "1.10"
+    command: |
+      julia -e 'using Pkg
+
+                println("--- :julia: Instantiating environment")
+                Pkg.add(["OpenCL", "pocl_jll"])
+                Pkg.develop(PackageSpec(name="Atomix", path="."))
+
+                println("+++ :julia: Running tests")
+                Pkg.test("Atomix", test_args=["--OpenCL"])'
+    agents:
+      queue: "juliagpu"
+      intel: "*"
+    if: build.message !~ /\[skip tests\]/
+    timeout_in_minutes: 15

Project.toml

@@ -10,15 +10,18 @@ UnsafeAtomics = "013be700-e6cd-48c3-b4a1-df204f14c38f"
 CUDA = "052768ef-5323-5732-b1bb-66c8b64840ba"
 Metal = "dde4c033-4e86-420c-a63e-0dd931031962"
 oneAPI = "8f75cd03-7ff8-4ecb-9b8f-daf728133b1b"
+OpenCL = "08131aa3-fb12-5dee-8b74-c09406e224a2"
 
 [extensions]
 AtomixCUDAExt = "CUDA"
 AtomixMetalExt = "Metal"
 AtomixoneAPIExt = "oneAPI"
+AtomixOpenCLExt = "OpenCL"
 
 [compat]
 CUDA = "5"
 Metal = "1"
 oneAPI = "1"
+OpenCL = "^0.10"
 UnsafeAtomics = "0.1, 0.2, 0.3"
 julia = "1.10"

ext/AtomixOpenCLExt.jl

@@ -0,0 +1,59 @@
+# TODO: respect ordering
+module AtomixOpenCLExt
+
+using Atomix: Atomix, IndexableRef
+using OpenCL: SPIRVIntrinsics, CLDeviceArray
+
+const CLIndexableRef{Indexable<:CLDeviceArray} = IndexableRef{Indexable}
+
+function Atomix.get(ref::CLIndexableRef, order)
+    error("not implemented")
+end
+
+function Atomix.set!(ref::CLIndexableRef, v, order)
+    error("not implemented")
+end
+
+@inline function Atomix.replace!(
+    ref::CLIndexableRef,
+    expected,
+    desired,
+    success_ordering,
+    failure_ordering,
+)
+    ptr = Atomix.pointer(ref)
+    expected = convert(eltype(ref), expected)
+    desired = convert(eltype(ref), desired)
+    begin
+        old = SPIRVIntrinsics.atomic_cmpxchg!(ptr, expected, desired)
+    end
+    return (; old = old, success = old === expected)
+end
+
+@inline function Atomix.modify!(ref::CLIndexableRef, op::OP, x, order) where {OP}
+    x = convert(eltype(ref), x)
+    ptr = Atomix.pointer(ref)
+    begin
+        old = if op === (+)
+            SPIRVIntrinsics.atomic_add!(ptr, x)
+        elseif op === (-)
+            SPIRVIntrinsics.atomic_sub!(ptr, x)
+        elseif op === (&)
+            SPIRVIntrinsics.atomic_and!(ptr, x)
+        elseif op === (|)
+            SPIRVIntrinsics.atomic_or!(ptr, x)
+        elseif op === xor
+            SPIRVIntrinsics.atomic_xor!(ptr, x)
+        elseif op === min
+            SPIRVIntrinsics.atomic_min!(ptr, x)
+        elseif op === max
+            SPIRVIntrinsics.atomic_max!(ptr, x)
+        else
+            error("not implemented")
+        end
+    end
+    return old => op(old, x)
+end
+
+end  # module AtomixOpenCLExt
+

test/runtests.jl

@@ -149,4 +149,8 @@ elseif "--oneAPI" in ARGS
     import Pkg
     Pkg.add("oneAPI")
     include("test_atomix_oneapi.jl")
+elseif "--OpenCL" in ARGS
+    import Pkg
+    Pkg.add(["OpenCL", "pocl_jll"])
+    include("test_atomix_opencl.jl")
 end

test/test_atomix_opencl.jl

@@ -0,0 +1,81 @@
+using OpenCL, pocl_jll
+using OpenCL: @allowscalar
+cl.platform!("pocl")
+
+@testset "AtomixOpenCLExt:extension_found" begin
+    @test !isnothing(Base.get_extension(Atomix, :AtomixOpenCLExt))
+end
+
+
+function opencl(f)
+    function g()
+        f()
+        nothing
+    end
+    OpenCL.@opencl g()
+end
+
+
+# Not implemented:
+#=
+function test_get_set()
+    A = CUDA.ones(Int, 3)
+    cuda() do
+        GC.@preserve A begin
+            ref = Atomix.IndexableRef(A, (1,))
+            x = Atomix.get(ref)
+            Atomix.set!(ref, -x)
+        end
+    end
+    @test collect(A) == [-1, 1, 1]
+end
+=#
+
+
+@testset "AtomixOpenCLExt:test_cas" begin
+    idx = (
+        data = 1,
+        cas1_ok = 2,
+        cas2_ok = 3,
+        # ...
+    )
+    @assert minimum(idx) >= 1
+    @assert maximum(idx) == length(idx)
+
+    A = OpenCL.zeros(Int32, length(idx))
+    opencl() do
+        GC.@preserve A begin
+            ref = Atomix.IndexableRef(A, (1,))
+            (old, success) = Atomix.replace!(ref, 0, 42)
+            A[idx.cas1_ok] = old == 0 && success
+            (old, success) = Atomix.replace!(ref, 0, 43)
+            A[idx.cas2_ok] = old == 42 && !success
+        end
+    end
+    @test collect(A) == [42, 1, 1]
+end
+
+
+@testset "AtomixOpenCLExt:test_inc" begin
+    A = OpenCL.CLArray(Int32(1):Int32(3))
+    opencl() do
+        GC.@preserve A begin
+            ref = Atomix.IndexableRef(A, (1,))
+            pre, post = Atomix.modify!(ref, +, 1)
+            A[2] = pre
+            A[3] = post
+        end
+    end
+    @test collect(A) == [2, 1, 2]
+end
+
+
+@testset "AtomixOpenCLExt:test_inc_sugar" begin
+    A = OpenCL.ones(Int32, 3)
+    opencl() do
+        GC.@preserve A begin
+            @atomic A[begin] += 1
+        end
+    end
+    @test collect(A) == [2, 1, 1]
+end