diff --git a/base/Base.jl b/base/Base.jl
index 1fc20293aa384..d77f034a89185 100644
--- a/base/Base.jl
+++ b/base/Base.jl
@@ -475,6 +475,9 @@ if isdefined(Core, :Compiler) && is_primary_base_module
     Docs.loaddocs(Core.Compiler.CoreDocs.DOCS)
 end
 
+# Formerly PrecompileTools
+include("invalidations.jl")
+
 # finally, now make `include` point to the full version
 for m in methods(include)
     delete_method(m)
diff --git a/base/invalidations.jl b/base/invalidations.jl
new file mode 100644
index 0000000000000..2540055c9159c
--- /dev/null
+++ b/base/invalidations.jl
@@ -0,0 +1,70 @@
+"""
+    @recompile_invalidations begin
+        using PkgA
+        ⋮
+    end
+
+Recompile any invalidations that occur within the given expression. This is generally intended to be used
+by users in creating "Startup" packages to ensure that the code compiled by package authors is not invalidated.
+"""
+macro recompile_invalidations(expr)
+    list = gensym(:list)
+    Expr(:toplevel,
+        :($list = ccall(:jl_debug_method_invalidation, Any, (Cint,), 1)),
+        Expr(:tryfinally,
+            esc(expr),
+            :(ccall(:jl_debug_method_invalidation, Any, (Cint,), 0))
+        ),
+        :(if ccall(:jl_generating_output, Cint, ()) == 1
+            foreach($precompile_mi, $invalidation_leaves($list))
+          end)
+    )
+end
+
+function precompile_mi(mi)
+    precompile(mi.specTypes) # TODO: Julia should allow one to pass `mi` directly (would handle `invoke` properly)
+    return
+end
+
+function invalidation_leaves(invlist)
+    umis = Set{Core.MethodInstance}()
+    # `queued` is a queue of length 0 or 1 of invalidated MethodInstances.
+    # We wait to read the `depth` to find out if it's a leaf.
+    queued, depth = nothing, 0
+    function cachequeued(item, nextdepth)
+        if queued !== nothing && nextdepth <= depth
+            push!(umis, queued)
+        end
+        queued, depth = item, nextdepth
+    end
+
+    i, ilast = firstindex(invlist), lastindex(invlist)
+    while i <= ilast
+        item = invlist[i]
+        if isa(item, Core.MethodInstance)
+            if i < lastindex(invlist)
+                nextitem = invlist[i+1]
+                if nextitem == "invalidate_mt_cache"
+                    cachequeued(nothing, 0)
+                    i += 2
+                    continue
+                end
+                if nextitem ∈ ("jl_method_table_disable", "jl_method_table_insert", "verify_methods")
+                    cachequeued(nothing, 0)
+                    push!(umis, item)
+                end
+                if isa(nextitem, Integer)
+                    cachequeued(item, nextitem)
+                    i += 2
+                    continue
+                end
+            end
+        end
+        if (isa(item, Method) || isa(item, Type)) && queued !== nothing
+            push!(umis, queued)
+            queued, depth = nothing, 0
+        end
+        i += 1
+    end
+    return umis
+end
\ No newline at end of file