Julia: add binding for runtime feature detection (#13992)

julia/deps/build.jl

@@ -51,9 +51,10 @@ elseif Sys.islinux()
 end
 
 if Sys.isunix()
-  try
-    push!(CUDAPATHS, replace(strip(read(`which nvcc`, String)), "bin/nvcc", "lib64"))
-  catch
+  nvcc_path = Sys.which("nvcc")
+  if nvcc_path ≢ nothing
+    @info "Found nvcc: $nvcc_path"
+    push!(CUDAPATHS, replace(nvcc_path, "bin/nvcc", "lib64"))
   end
 end
 

julia/src/MXNet.jl

@@ -137,6 +137,7 @@ export to_graphviz
 
 include("base.jl")
 
+include("runtime.jl")
 include("context.jl")
 include("util.jl")
 

julia/src/base.jl

@@ -85,12 +85,11 @@ function mx_get_last_error()
 end
 
 "Utility macro to call MXNet API functions"
-macro mxcall(fv, argtypes, args...)
-  f = eval(fv)
+macro mxcall(f, argtypes, args...)
   args = map(esc, args)
   quote
-    _mxret = ccall(($(QuoteNode(f)), $MXNET_LIB),
-                   Cint, $argtypes, $(args...))
+    _mxret = ccall(($f, $MXNET_LIB),
+                   Cint, $(esc(argtypes)), $(args...))
     if _mxret != 0
       err_msg = mx_get_last_error()
       throw(MXError(err_msg))

julia/src/runtime.jl

@@ -0,0 +1,76 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# License); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# AS IS BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+# runtime detection of compile time features in the native library
+
+module MXRuntime
+
+using ..mx
+
+export LibFeature
+export feature_list, isenabled
+
+# defined in include/mxnet/c_api.h
+struct LibFeature
+  _name::Ptr{Cchar}
+  enabled::Bool
+end
+
+function Base.getproperty(x::LibFeature, p::Symbol)
+  (p == :name) && return unsafe_string(getfield(x, :_name))
+  getfield(x, p)
+end
+
+Base.show(io::IO, x::LibFeature) =
+  print(io, ifelse(x.enabled, "✔", "✖"), " ", x.name)
+
+"""
+    feature_list()
+
+Check the library for compile-time features.
+The list of features are maintained in libinfo.h and libinfo.cc
+"""
+function feature_list()
+  ref = Ref{Ptr{LibFeature}}(C_NULL)
+  s = Ref{Csize_t}(C_NULL)
+  @mx.mxcall(:MXLibInfoFeatures, (Ref{Ptr{LibFeature}}, Ref{Csize_t}), ref, s)
+  unsafe_wrap(Array, ref[], s[])
+end
+
+"""
+    isenabled(x::Symbol)::Bool
+
+Returns the given runtime feature is enabled or not.
+
+```julia-repl
+julia> mx.isenabled(:CUDA)
+false
+
+julia> mx.isenabled(:CPU_SSE)
+true
+```
+
+See also `mx.feature_list()`.
+"""
+isenabled(x::Symbol) =
+  any(feature_list()) do i
+    Symbol(i.name) == x && i.enabled
+  end
+
+end  # module MXRuntime
+
+using .MXRuntime