Merge pull request #48435 from giordano/mg/libblas

Fix `Base.libblas_name`/`Base.liblapack_name`

base/Base.jl

@@ -186,10 +186,6 @@ end
 include(strcat((length(Core.ARGS)>=2 ? Core.ARGS[2] : ""), "build_h.jl"))     # include($BUILDROOT/base/build_h.jl)
 include(strcat((length(Core.ARGS)>=2 ? Core.ARGS[2] : ""), "version_git.jl")) # include($BUILDROOT/base/version_git.jl)
 
-# These used to be in build_h.jl and are retained for backwards compatibility
-const libblas_name = "libblastrampoline"
-const liblapack_name = "libblastrampoline"
-
 # numeric operations
 include("hashing.jl")
 include("rounding.jl")
@@ -290,6 +286,11 @@ include("sysinfo.jl")
 include("libc.jl")
 using .Libc: getpid, gethostname, time
 
+# These used to be in build_h.jl and are retained for backwards compatibility.
+# NOTE: keep in sync with `libblastrampoline_jll.libblastrampoline`.
+const libblas_name = "libblastrampoline" * (Sys.iswindows() ? "-5" : "")
+const liblapack_name = libblas_name
+
 # Logging
 include("logging.jl")
 using .CoreLogging

stdlib/LinearAlgebra/test/blas.jl

@@ -4,6 +4,7 @@ module TestBLAS
 
 using Test, LinearAlgebra, Random
 using LinearAlgebra: BlasReal, BlasComplex
+using Libdl: dlsym, dlopen
 fabs(x::Real) = abs(x)
 fabs(x::Complex) = abs(real(x)) + abs(imag(x))
 
@@ -713,4 +714,11 @@ end
     end
 end
 
+# Make sure we can use `Base.libblas_name`.  Avoid causing
+# https://github.com/JuliaLang/julia/issues/48427 again.
+@testset "libblas_name" begin
+    dot_sym = dlsym(dlopen(Base.libblas_name), "cblas_ddot" * (Sys.WORD_SIZE == 64 ? "64_" : ""))
+    @test 23.0 === @ccall $(dot_sym)(2::Int, [2.0, 3.0]::Ref{Cdouble}, 1::Int, [4.0, 5.0]::Ref{Cdouble}, 1::Int)::Cdouble
+end
+
 end # module TestBLAS

stdlib/libblastrampoline_jll/src/libblastrampoline_jll.jl

@@ -18,6 +18,7 @@ artifact_dir = ""
 libblastrampoline_handle = C_NULL
 libblastrampoline_path = ""
 
+# NOTE: keep in sync with `Base.libblas_name` and `Base.liblapack_name`.
 const libblastrampoline = if Sys.iswindows()
     "libblastrampoline-5.dll"
 elseif Sys.isapple()