Fix unsafe_wrap of a view. (#452)

And some other small fixes.

perf/array.jl

@@ -2,7 +2,7 @@ const m = 512
 const n = 1000
 
 for (S, smname) in [(Metal.PrivateStorage,"private"), (Metal.SharedStorage,"shared")]
-    group = addgroup!(SUITE, "$smname array")
+    local group = addgroup!(SUITE, "$smname array")
 
     # generate some arrays
     cpu_mat = rand(rng, Float32, m, n)

src/array.jl

@@ -556,7 +556,7 @@ Base.unsafe_convert(::Type{MTL.MTLBuffer}, A::PermutedDimsArray) =
 ## unsafe_wrap
 
 function Base.unsafe_wrap(::Type{<:Array}, arr::MtlArray{T,N}, dims=size(arr); own=false) where {T,N}
-    return unsafe_wrap(Array{T,N}, arr.data[], dims; own)
+    return unsafe_wrap(Array{T,N}, pointer(arr), dims; own)
 end
 
 function Base.unsafe_wrap(t::Type{<:Array{T}}, buf::MTLBuffer, dims; own=false) where T

src/device/array.jl

@@ -149,7 +149,7 @@ Base.show(io::IO, a::MtlDeviceArray) =
 Base.show(io::IO, mime::MIME"text/plain", a::MtlDeviceArray) = show(io, a)
 
 @inline function Base.unsafe_view(A::MtlDeviceVector{T}, I::Vararg{Base.ViewIndex,1}) where {T}
-    ptr = pointer(A) + (I[1].start-1)*sizeof(T)
+    ptr = pointer(A, I[1].start)
     len = I[1].stop - I[1].start + 1
     return MtlDeviceArray(len, ptr)
 end

test/array.jl

@@ -370,6 +370,15 @@ end
     arr2 .+= 1;
     @test all(arr2 .== 2)
     @test all(marr2 .== 2)
+
+    @testset "Issue #451" begin
+        a = mtl(reshape(Float32.(1:60), 5,4,3);storage=Metal.SharedStorage)
+        view_a = @view a[:,1:4,2]
+        b = copy(unsafe_wrap(Array, view_a))
+        c = Array(view_a)
+
+        @test b == c
+    end
 end
 
 @testset "ReshapedArray" begin