trimming: Locate package modules by PkgId (#57672)

As recommended in
#57589 (comment)

Author: topolarity

contrib/juliac-buildscript.jl

@@ -205,14 +205,11 @@ let mod = Base.include(Base.__toplevel__, inputfile)
 end
 
 # Additional method patches depending on whether user code loads certain stdlibs
-let loaded = Base.loaded_modules_array()
-    function find_loaded_module(name)
-        idx = findfirst((m) -> Symbol(m) === name, loaded)
-        idx === nothing && return nothing
-        return loaded[idx]
-    end
+let
+    find_loaded_root_module(key::Base.PkgId) = Base.maybe_root_module(key)
 
-    SparseArrays = find_loaded_module(:SparseArrays)
+    SparseArrays = find_loaded_root_module(Base.PkgId(
+        Base.UUID("2f01184e-e22b-5df5-ae63-d93ebab69eaf"), "SparseArrays"))
     if SparseArrays !== nothing
         @eval SparseArrays.CHOLMOD begin
             function __init__()
@@ -228,10 +225,20 @@ let loaded = Base.loaded_modules_array()
         end
     end
 
-    Artifacts = find_loaded_module(:Artifacts)
+    Artifacts = find_loaded_root_module(Base.PkgId(
+        Base.UUID("56f22d72-fd6d-98f1-02f0-08ddc0907c33"), "Artifacts"))
     if Artifacts !== nothing
         @eval Artifacts begin
-            function _artifact_str(__module__, artifacts_toml, name, path_tail, artifact_dict, hash, platform, _::Val{lazyartifacts}) where lazyartifacts
+            function _artifact_str(
+                __module__,
+                artifacts_toml,
+                name,
+                path_tail,
+                artifact_dict,
+                hash,
+                platform,
+                _::Val{LazyArtifacts}
+            ) where LazyArtifacts
                 # If the artifact exists, we're in the happy path and we can immediately
                 # return the path to the artifact:
                 dirs = artifacts_dirs(bytes2hex(hash.bytes))
@@ -245,28 +252,32 @@ let loaded = Base.loaded_modules_array()
         end
     end
 
-    Pkg = find_loaded_module(:Pkg)
+    Pkg = find_loaded_root_module(Base.PkgId(
+        Base.UUID("44cfe95a-1eb2-52ea-b672-e2afdf69b78f"), "Pkg"))
     if Pkg !== nothing
         @eval Pkg begin
             __init__() = rand() #TODO, methods that do nothing don't get codegened
         end
     end
 
-    StyledStrings = find_loaded_module(:StyledStrings)
+    StyledStrings = find_loaded_root_module(Base.PkgId(
+        Base.UUID("f489334b-da3d-4c2e-b8f0-e476e12c162b"), "StyledStrings"))
     if StyledStrings !== nothing
         @eval StyledStrings begin
             __init__() = rand()
         end
     end
 
-    Markdown = find_loaded_module(:Markdown)
+    Markdown = find_loaded_root_module(Base.PkgId(
+        Base.UUID("d6f4376e-aef5-505a-96c1-9c027394607a"), "Markdown"))
     if Markdown !== nothing
         @eval Markdown begin
             __init__() = rand()
         end
     end
 
-    JuliaSyntaxHighlighting = find_loaded_module(:JuliaSyntaxHighlighting)
+    JuliaSyntaxHighlighting = find_loaded_root_module(Base.PkgId(
+        Base.UUID("ac6e5ff7-fb65-4e79-a425-ec3bc9c03011"), "JuliaSyntaxHighlighting"))
     if JuliaSyntaxHighlighting !== nothing
         @eval JuliaSyntaxHighlighting begin
             __init__() = rand()