allow the Compiler.jl stdlib to be installed on older version of Julia

Compiler/Project.toml

@@ -1,3 +1,3 @@
 name = "Compiler"
 uuid = "807dbc54-b67e-4c79-8afb-eafe4df6f2e1"
-version = "0.0.1"
+version = "0.0.2"

Compiler/src/Compiler.jl

@@ -1,15 +1,28 @@
 # This file is a part of Julia. License is MIT: https://julialang.org/license
 
+if isdefined(Base, :end_base_include) && !isdefined(Base, :Compiler)
+
+# Define a dummy `Compiler` module to make it installable even on Julia versions where
+# Compiler.jl is not available as a standard library.
+@eval module Compiler
+    function __init__()
+        println("""
+        The `Compiler` standard library is not available for this version of Julia.
+        Use Julia version `v"1.12.0-DEV.1581"` or later.
+        """)
+    end
+end
+
 # When generating an incremental precompile file, we first check whether we
 # already have a copy of this *exact* code in the system image. If so, we
 # simply generates a pkgimage that has the dependency edges we recorded in
 # the system image and simply returns that copy of the compiler. If not,
 # we proceed to load/precompile this as an ordinary package.
-if isdefined(Base, :generating_output) && Base.generating_output(true) &&
+elseif (isdefined(Base, :generating_output) && Base.generating_output(true) &&
         Base.samefile(joinpath(Sys.BINDIR, Base.DATAROOTDIR, Base._compiler_require_dependencies[1][2]), @eval @__FILE__) &&
         !Base.any_includes_stale(
             map(Base.compiler_chi, Base._compiler_require_dependencies),
-            "sysimg", nothing)
+            "sysimg", nothing))
 
     Base.prepare_compiler_stub_image!()
     append!(Base._require_dependencies, map(Base.expand_compiler_path, Base._compiler_require_dependencies))
@@ -167,12 +180,12 @@ include("optimize.jl")
 include("bootstrap.jl")
 include("reflection_interface.jl")
 
-if isdefined(Base, :IRShow)
-    @eval module IRShow
-        using ..Compiler: Compiler
-        # During bootstrap, Base will later include this into its own "IRShow module"
-        Compiler.include(IRShow, "ssair/show.jl")
-    end
+module IRShow end
+if !isdefined(Base, :end_base_include)
+    # During bootstrap, skip including this file and defer it to base/show.jl to include later
+else
+    # When this module is loaded as the standard library, include this file as usual
+    include(IRShow, "ssair/show.jl")
 end
 
 end # baremodule Compiler

Compiler/src/ssair/show.jl

@@ -1,7 +1,8 @@
 # This file is a part of Julia. License is MIT: https://julialang.org/license
 
-# This file is not loaded into `Core.Compiler` but rather loaded into the context of
-# `Base.IRShow` and thus does not participate in bootstrapping.
+# This file does not participate in bootstrapping, but is included in the system image by
+# being loaded from `base/show.jl`. Compiler.jl as the standard library will simply include
+# this file in the context of `Compiler.IRShow`.
 
 using Base, Core.IR
 
@@ -1135,3 +1136,12 @@ function Base.show(io::IO, tinf::Timings.Timing)
 end
 
 @specialize
+
+const __debuginfo = Dict{Symbol, Any}(
+    # :full => src -> statementidx_lineinfo_printer(src), # and add variable slot information
+    :source => src -> statementidx_lineinfo_printer(src),
+    # :oneliner => src -> statementidx_lineinfo_printer(PartialLineInfoPrinter, src),
+    :none => src -> lineinfo_disabled,
+    )
+const default_debuginfo = Ref{Symbol}(:none)
+debuginfo(sym) = sym === :default ? default_debuginfo[] : sym

base/show.jl

@@ -2821,19 +2821,8 @@ function show(io::IO, vm::Core.TypeofVararg)
     end
 end
 
-module IRShow
-    using ..Compiler: Compiler
-    Base.include(IRShow, Base.strcat(Base.BUILDROOT, "../usr/share/julia/Compiler/src/ssair/show.jl"))
-
-    const __debuginfo = Dict{Symbol, Any}(
-        # :full => src -> statementidx_lineinfo_printer(src), # and add variable slot information
-        :source => src -> statementidx_lineinfo_printer(src),
-        # :oneliner => src -> statementidx_lineinfo_printer(PartialLineInfoPrinter, src),
-        :none => src -> lineinfo_disabled,
-        )
-    const default_debuginfo = Ref{Symbol}(:none)
-    debuginfo(sym) = sym === :default ? default_debuginfo[] : sym
-end
+Compiler.include(Compiler.IRShow, "ssair/show.jl") # define `show` for the compiler types
+const IRShow = Compiler.IRShow # an alias for compatibility
 
 function show(io::IO, src::CodeInfo; debuginfo::Symbol=:source)
     # Fix slot names and types in function body