Use stacked method tables

Author: vchuravy

Project.toml

@@ -49,3 +49,7 @@ oneAPI_Support_jll = "0.8"
 
 [extras]
 libigc_jll = "94295238-5935-5bd7-bb0f-b00942e9bdd5"
+
+[sources]
+GPUCompiler = {url="https://github.com/JuliaGPU/GPUCompiler.jl", rev="vc/mtv"}
+SPIRVIntrinsics = {url="https://github/JuliaGPU/OpenCL.jl", rev="vc/mtv", subdir="lib/intrinsics"}

src/compiler/compilation.jl

@@ -6,7 +6,7 @@ const oneAPICompilerJob = CompilerJob{SPIRVCompilerTarget,oneAPICompilerParams}
 
 GPUCompiler.runtime_module(::oneAPICompilerJob) = oneAPI
 
-GPUCompiler.method_table(::oneAPICompilerJob) = method_table
+GPUCompiler.method_table_view(job::oneAPICompilerJob) = GPUCompiler.StackedMethodTable(job.world, method_table, spirv_method_table)
 
 # filter out OpenCL built-ins
 # TODO: eagerly lower these using the translator API

src/oneAPI.jl

@@ -25,10 +25,40 @@ include("../lib/level-zero/oneL0.jl")
 using .oneL0
 functional() = oneL0.functional[]
 
+
+## device overrides
+
+# local method table for device functions
+Base.Experimental.@MethodTable(method_table)
+
+macro device_override(ex)
+    esc(quote
+        Base.Experimental.@overlay($method_table, $ex)
+    end)
+end
+
+macro device_function(ex)
+    ex = macroexpand(__module__, ex)
+    def = ExprTools.splitdef(ex)
+
+    # generate a function that errors
+    def[:body] = quote
+        error("This function is not intended for use on the CPU")
+    end
+
+    esc(quote
+        $(ExprTools.combinedef(def))
+        @device_override $ex
+    end)
+end
+
 # device functionality
 import SPIRVIntrinsics
 SPIRVIntrinsics.@import_all
 SPIRVIntrinsics.@reexport_public
+
+const spirv_method_table = SPIRVIntrinsics.method_table
+
 include("device/runtime.jl")
 include("device/array.jl")
 include("device/quirks.jl")