include ssair/show.jl in the context of Compiler

To ensure that stale precompilation caches aren't used.

Compiler/src/Compiler.jl

@@ -180,12 +180,12 @@ include("optimize.jl")
 include("bootstrap.jl")
 include("reflection_interface.jl")
 
-if isdefined(Base, :end_base_include)
-    @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
 

base/show.jl

@@ -2821,10 +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"))
-end
+@eval Compiler include(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