Enable BLAS-switching via LBT

src/BLIS.jl

@@ -5,19 +5,21 @@ using Libdl
 using blis_jll
 using LinearAlgebra
 
+global libblis_path = ""
 global libblis = C_NULL
 
 __init__() = begin
     if length(get(ENV, "BLISDIR", "")) > 0
         # BLIS installation overriden by environmental variables.
         @info "Using custom defined BLIS installation instead of blis_jll."
+        global libblis_path = joinpath(get(ENV, "BLISDIR", ""), "lib/libblis")
         global libblis = dlopen(joinpath(get(ENV, "BLISDIR", ""), "lib/libblis"))
     else
-        blis_path = blis_jll.blis_path
+        global libblis_path = blis_jll.blis_path
         # Use BinaryBuilder provided BLIS library.
-        @info "blis_jll yields BLIS installation: $blis_path."
-        global libblis = dlopen(blis_path)
+        @info "blis_jll yields BLIS installation: $libblis_path."
     end
+    global libblis = dlopen(libblis_path)
 end
 
 # Data types.

src/switch_blas.jl

@@ -0,0 +1,26 @@
+# LBT-forward BLAS calls
+#
+
+global fallback_lib = []
+
+lbt_enable_blis(; clear=false) = begin
+    if length(fallback_lib) == 0
+        libs = LinearAlgebra.BLAS.lbt_get_config().loaded_libs
+        if length(libs) > 0
+            # Save currently loaded library path for resetting.
+            fallback_lib = [fallback_lib..., ]
+        end
+
+        LinearAlgebra.BLAS.lbt_forward(libblis_path; clear=clear)
+    else
+        @warn "BLIS.lbt_enable_blis: BLIS already loaded. Not doing anything."
+    end
+end
+
+lbt_disable_blis() = begin
+    if length(fallback_lib) > 0
+        LinearAlgebra.BLAS.lbt_forward(fallback_lib[1]; clear=true)
+    else
+        @warn "BLIS.lbt_enable_blis: Fallback library not found. Not doing anything."
+    end
+end