@@ -159,10 +159,14 @@ let emacs = stdenv.mkDerivation (lib.optionalAttrs nativeComp {
159159 '' + lib.optionalString (nativeComp && withNS) ''
160160 ln -snf $out/lib/emacs/*/native-lisp $out/Applications/Emacs.app/Contents/native-lisp
161161 '' + lib.optionalString nativeComp ''
162− $out/bin/emacs --batch \
163− -l comp --eval "(mapatoms (lambda (s) \
164− (when (subr-primitive-p (symbol-function s)) \
165− (comp-trampoline-compile s))))"
162+ echo "Generating native-compiled trampolines..."
163+ # precompile trampolines in parallel, but avoid spawning one process per trampoline.
164+ # 1000 is a rough lower bound on the number of trampolines compiled.
165+ $out/bin/emacs --batch --eval "(mapatoms (lambda (s) \
166+ (when (subr-primitive-p (symbol-function s)) (print s))))" \
167+ | xargs -n $((1000/NIX_BUILD_CORES + 1)) -P $NIX_BUILD_CORES \
168+ $out/bin/emacs --batch -l comp --eval "(while argv \
169+ (comp-trampoline-compile (intern (pop argv))))"
166170 mkdir -p $out/share/emacs/native-lisp
167171 $out/bin/emacs --batch \
168172 --eval "(add-to-list 'comp-eln-load-path \"$out/share/emacs/native-lisp\")" \