Serialize new method roots

base/compiler/typeinfer.jl

@@ -1,5 +1,9 @@
 # This file is a part of Julia. License is MIT: https://julialang.org/license
 
+# Tracking of newly-inferred MethodInstances during precompilation
+const track_newly_inferred = RefValue{Bool}(false)
+const newly_inferred = MethodInstance[]
+
 # build (and start inferring) the inference frame for the top-level MethodInstance
 function typeinf(interp::AbstractInterpreter, result::InferenceResult, cache::Symbol)
     frame = InferenceState(result, cache, interp)
@@ -386,6 +390,12 @@ function cache_result!(interp::AbstractInterpreter, result::InferenceResult)
         inferred_result = transform_result_for_cache(interp, linfo, valid_worlds, result.src)
         relocatability = isa(inferred_result, Vector{UInt8}) ? inferred_result[end] : UInt8(0)
         code_cache(interp)[linfo] = CodeInstance(result, inferred_result, valid_worlds, relocatability)
+        if track_newly_inferred[]
+            m = linfo.def
+            if isa(m, Method)
+                m.module != Core && push!(newly_inferred, linfo)
+            end
+        end
     end
     unlock_mi_inference(interp, linfo)
     nothing

base/loading.jl

@@ -1410,13 +1410,16 @@ function include_package_for_output(pkg::PkgId, input::String, depot_path::Vecto
         task_local_storage()[:SOURCE_PATH] = source
     end
 
+    Core.Compiler.track_newly_inferred.x = true
     try
         Base.include(Base.__toplevel__, input)
     catch ex
         precompilableerror(ex) || rethrow()
         @debug "Aborting `create_expr_cache'" exception=(ErrorException("Declaration of __precompile__(false) not allowed"), catch_backtrace())
         exit(125) # we define status = 125 means PrecompileableError
     end
+    Core.Compiler.track_newly_inferred.x = false
+    ccall(:jl_set_newly_inferred, Cvoid, (Any,), Core.Compiler.newly_inferred)
 end
 
 const PRECOMPILE_TRACE_COMPILE = Ref{String}()