Add test-JL_stdlibs target for precompiling stdlibs with JuliaLowering

This has a significant blacklist for now, but eventually we should be
able to build all of our stdlibs with JuliaLowering (and even include it
by default in the sysimage)

Author: topolarity

base/Base.jl

@@ -397,8 +397,8 @@ function __init__()
     if get_bool_env("JULIA_USE_FLISP_PARSER", false) === false
         JuliaSyntax.enable_in_core!()
     end
-    if get_bool_env("JULIA_USE_FLISP_LOWERING", true) === false
-        # This does not work by default, but JuliaLowering can be added to
+    if (@isdefined JuliaLowering) && get_bool_env("JULIA_USE_FLISP_LOWERING", true) === false
+        # This is not available by default, but JuliaLowering can be added to
         # Base after-the-fact via an incremental sysimage build.
         JuliaLowering.activate!()
     end

test/JL_stdlibs.jl

@@ -0,0 +1,38 @@
+import Libdl
+
+### 34 / 51 (non-sysimage) stdlibs precompile successfully with JuliaLowering ###
+const INCOMPATIBLE_STDLIBS = String[
+    "Statistics", "JuliaSyntaxHighlighting", "Markdown", "Downloads", "LibGit2",
+    "InteractiveUtils", "Test", "REPL", "Pkg", "LazyArtifacts", "SparseArrays",
+    "Dates", "TOML"
+]
+
+# ensure JL-inclusive sysimage is built / available
+run(`$(ENV["MAKE"]) -C $(ENV["BUILDROOT"]) -f sysimage.mk sysimg-JL-$(ENV["JULIA_BUILD_MODE"])`)
+
+stdlibs_to_test = filter(name -> !in(name, INCOMPATIBLE_STDLIBS), String[
+    strip(split(line, "=")[1])
+    for line in readlines("$(ENV["JULIAHOME"])/stdlib/Project.toml")[2:end]
+])
+configs = [
+    ``=>Base.CacheFlags(check_bounds=0, debug_level=2, opt_level=3),
+    ``=>Base.CacheFlags(check_bounds=1, debug_level=2, opt_level=3),
+]
+compilecache_command = "using Base: CacheFlags; Base.Precompilation.precompilepkgs($(stdlibs_to_test); configs=$(configs))"
+
+debug = ENV["JULIA_BUILD_MODE"] == "debug" ? "-debug" : ""
+sysimage = joinpath(dirname(unsafe_string(Base.JLOptions().image_file)), "sys-JL$(debug).$(Libdl.dlext)")
+
+# pre-compile stdlibs (into temporary depot)
+mktempdir() do tmp_depot
+    cmd = addenv(
+        `$(ENV["JULIA_EXECUTABLE"]) --sysimage $(sysimage) --startup-file=no -e $compilecache_command`,
+	"JULIA_LOAD_PATH" => "@stdlib$(Base.Linking.pathsep)$(joinpath(ENV["JULIAHOME"], "stdlib"))",
+        "JULIA_CPU_TARGET" => "sysimage",
+        "JULIA_USE_FLISP_LOWERING" => "0",
+        "JULIA_USE_FALLBACK_REPL" => "0",
+        "JULIA_DEPOT_PATH" => tmp_depot,
+	; inherit = true
+    )
+    success(run(cmd))
+end

test/Makefile

@@ -11,6 +11,13 @@ export JULIA_LOAD_PATH := @$(PATHSEP)@stdlib
 unexport JULIA_PROJECT :=
 unexport JULIA_BINDIR :=
 
+# used by JL_stdlibs.jl test (invokes `make` for JL sysimage)
+export MAKE
+export BUILDROOT
+export JULIAHOME
+export JULIA_EXECUTABLE
+export JULIA_BUILD_MODE
+
 TESTGROUPS = unicode strings compiler Compiler JuliaSyntax JuliaLowering
 TESTS = all default stdlib $(TESTGROUPS) \
 		$(patsubst $(STDLIBDIR)/%/,%,$(dir $(wildcard $(STDLIBDIR)/*/.))) \
@@ -33,7 +40,7 @@ default:
 
 .PHONY: $(TESTS)
 $(TESTS):
-	@cd $(SRCDIR) && \
+	+@cd $(SRCDIR) && \
 	$(call PRINT_JULIA, $(call spawn,$(JULIA_EXECUTABLE)) $(TEST_JULIA_OPTIONS) ./runtests.jl $(TEST_SCRIPT_OPTIONS) $@)
 
 .PHONY: install-revise-deps