Only apply the extra flags if we have confirmed that the compiler is Xcode's clang

Author: DilumAluthge

src/PackageCompiler.jl

@@ -14,9 +14,13 @@ using p7zip_jll: p7zip_path
 
 export create_sysimage, create_app, create_library
 
-include("juliaconfig.jl")
+# Vendored:
 include("../ext/TerminalSpinners.jl")
+
+# Source code for this package:
+include("juliaconfig.jl")
 include("library_selection.jl")
+include("xcode.jl")
 
 
 ##############
@@ -712,7 +716,7 @@ function create_sysimg_from_object_file(object_files::Vector{String},
     mkpath(dirname(sysimage_path))
     # Prevent compiler from stripping all symbols from the shared lib.
     if Sys.isapple()
-        if _xcode_clt_major_version() > 14
+        if _is_xcode_clt_and_is_gte_xcode_15()
             o_file_flags = `-Wl,-all_load $object_files -Wl,-ld_classic`
         else
             o_file_flags = `-Wl,-all_load $object_files`
@@ -726,24 +730,6 @@ function create_sysimg_from_object_file(object_files::Vector{String},
     return nothing
 end
 
-function _xcode_clt_major_version()
-    cmd = `pkgutil --pkg-info=com.apple.pkg.CLTools_Executables`
-    @debug "_xcode_clt_major_version(): Attempting to run command" cmd
-    # The `ignorestatus` allows us to proceed (with a warning) if
-    # the command does not run successfully.
-    output = strip(read(ignorestatus(cmd), String)) * "\n"
-    r = r"version: (.*)\n"
-    m = match(r, output)
-    if isnothing(m)
-        @warn "Could not determine the version of the Command Line Tools, assuming greater than 14"
-        major_version_str = "15"
-    else
-        major_version_str = split(m[1], '.')[1]
-    end
-    major_version_int = parse(Int, major_version_str)
-    return major_version_int
-end
-
 function get_extra_linker_flags(version, compat_level, soname)
     current_ver_arg = ``
     compat_ver_arg = ``

src/xcode.jl

@@ -0,0 +1,62 @@
+# Get the compiler command from `get_compiler_cmd()`, and run `cc --version`, and parse the
+# output to determine whether or not the compiler is an Xcode Clang.
+function _is_xcode_clt()
+    cmd = `$(get_compiler_cmd()) --version`
+    @debug "_active_compiler_is_xcode_clt(): Attempting to run command" cmd
+    output = "\n" * strip(read(ignorestatus(cmd), String)) * "\n"
+    is_apple_clang = occursin(r"Apple clang version", output)
+    installed_dir_m = match(r"\nInstalledDir: ([\w\/]*?)\n", output)
+    if isnothing(installed_dir_m)
+        return false
+    end
+    installed_dir_str = strip(installed_dir[1])
+    is_xcode_app = startswith(installed_dir_str, "/Applications/Xcode.app/")
+    is_xcode_clt = startswith(installed_dir_str, "/Library/Developer/CommandLineTools/")
+    res = is_apple_clang && (is_xcode_app || is_xcode_clt)
+end
+
+# Run `pkgutil` to get the version number of the Xcode CLT (Command Line Tools), and return
+# the major version number as an integer.
+function _xcode_clt_major_version()
+    cmd = `pkgutil --pkg-info=com.apple.pkg.CLTools_Executables`
+    @debug "_xcode_clt_major_version(): Attempting to run command" cmd
+    # The `ignorestatus` allows us to proceed if the command does
+    # not run successfully.
+    output = "\n" * strip(read(ignorestatus(cmd), String)) * "\n"
+    r = r"version: (.*)\n"
+    m = match(r, output)
+    if isnothing(m)
+        major_version_str = nothing
+    else
+        major_version_str = split(m[1], '.')[1]
+    end
+    major_version_int = parse(Int, major_version_str)
+    return major_version_int
+end
+
+# Return true iff the Xcode CLT version is >= 15.
+# "gte" = greater than or equal to.
+function _is_gte_xcode_15()
+    major_version_int = _xcode_clt_major_version()
+    isnothing(major_version_int) && return nothing
+    return major_version_int >= 15
+end
+
+# Return true iff the compiler is Xcode Clang AND the Xcode CLT version is >= 15.
+#
+# If the user sets the JULIA_PACKAGECOMPILER_XCODE_CLT_MAJOR_VERSION environment variable,
+# we skip our attempt at auto-detection, and instead use whatever value the user gave us.
+function _is_xcode_clt_and_is_gte_xcode_15()
+    str = strip(get(ENV, "JULIA_PACKAGECOMPILER_XCODE_CLT_MAJOR_VERSION", ""))
+    ver_int = tryparse(Int, str)
+    (ver_int isa Int) && return ver_int
+    if _is_xcode_clt()
+        b = _is_gte_xcode_15()
+        if isnothing(b)
+            @warn "Could not determine the version of the Command Line Tools, assuming less than or equal to 14"
+        end
+        return b
+    else
+        false
+    end
+end