Backporting the libblas and vendor() improvements to 1.8

NEWS.md

@@ -159,6 +159,11 @@ Standard library changes
  As a consequence, products of bi-, tri- and symmetric tridiagonal matrices with each
  other result in dense output. Moreover, constructing 3-arg similar matrices of special
  "sparse" matrices of (nonstatic) matrices now fails for the lack of `zero(::Type{Matrix{T}})`.
+* We are now wholly reliant on libblastrampoline (LBT) for calling
+ BLAS and LAPACK. OpenBLAS is shipped by default, but building the
+ system image with other BLAS/LAPACK libraries is not
+ supported. Instead, it is recommended that the LBT mechanism be used
+ for swapping BLAS/LAPACK with vendor provided ones. ([#44360])
 
 #### Printf
 

base/Base.jl

@@ -161,6 +161,10 @@ 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")

base/Makefile

@@ -47,8 +47,6 @@ else
  @echo "const MACHINE = \"$(XC_HOST)\"" >> $@
 endif
  @echo "const libm_name = \"$(LIBMNAME)\"" >> $@
- @echo "const libblas_name = \"$(LIBBLASNAME)\"" >> $@
- @echo "const liblapack_name = \"$(LIBLAPACKNAME)\"" >> $@
 ifeq ($(USE_BLAS64), 1)
  @echo "const USE_BLAS64 = true" >> $@
 else

base/twiceprecision.jl

@@ -462,6 +462,7 @@ range_start_step_length(a::IEEEFloat, st::Real, len::Integer) =
 range_start_step_length(a::IEEEFloat, st::IEEEFloat, len::Integer) =
  range_start_step_length(promote(a, st)..., len)
 
+
 function range_start_step_length(a::T, st::T, len::Integer) where T<:IEEEFloat
  len = len + 0 # promote with Int
  start_n, start_d = rat(a)

stdlib/LinearAlgebra/Project.toml

@@ -4,6 +4,7 @@ uuid = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
 [deps]
 Libdl = "8f399da3-3557-5675-b5ff-fb832c97cbdb"
 libblastrampoline_jll = "8e850b90-86db-534c-a0d3-1478176c7d93"
+OpenBLAS_jll = "4536629a-c528-5b80-bd46-f80d51c5b363"
 
 [extras]
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"

stdlib/LinearAlgebra/src/LinearAlgebra.jl

@@ -19,6 +19,8 @@ using Base: IndexLinear, promote_eltype, promote_op, promote_typeof,
  @propagate_inbounds, @pure, reduce, typed_hvcat, typed_vcat, require_one_based_indexing,
  splat
 using Base.Broadcast: Broadcasted, broadcasted
+using OpenBLAS_jll
+using libblastrampoline_jll
 import Libdl
 
 export
@@ -539,42 +541,9 @@ function versioninfo(io::IO=stdout)
  return nothing
 end
 
-function find_library_path(name)
- shlib_ext = string(".", Libdl.dlext)
- if !endswith(name, shlib_ext)
- name_ext = string(name, shlib_ext)
- end
-
- # On windows, we look in `bin` and never in `lib`
- @static if Sys.iswindows()
- path = joinpath(Sys.BINDIR, name_ext)
- isfile(path) && return path
- else
- # On other platforms, we check `lib/julia` first, and if that doesn't exist, `lib`.
- path = joinpath(Sys.BINDIR, Base.LIBDIR, "julia", name_ext)
- isfile(path) && return path
-
- path = joinpath(Sys.BINDIR, Base.LIBDIR, name_ext)
- isfile(path) && return path
- end
-
- # If we can't find it by absolute path, we'll try just passing this straight through to `dlopen()`
- return name
-end
-
 function __init__()
  try
- libblas_path = find_library_path(Base.libblas_name)
- liblapack_path = find_library_path(Base.liblapack_name)
- # We manually `dlopen()` these libraries here, so that we search with `libjulia-internal`'s
- # `RPATH` and not `libblastrampoline's`. Once it's been opened, when LBT tries to open it,
- # it will find the library already loaded.
- libblas_path = Libdl.dlpath(Libdl.dlopen(libblas_path))
- BLAS.lbt_forward(libblas_path; clear=true)
- if liblapack_path != libblas_path
- liblapack_path = Libdl.dlpath(Libdl.dlopen(liblapack_path))
- BLAS.lbt_forward(liblapack_path)
- end
+ BLAS.lbt_forward(OpenBLAS_jll.libopenblas_path; clear=true)
  BLAS.check()
  catch ex
  Base.showerror_nostdio(ex, "WARNING: Error during initialization of module LinearAlgebra")