derivations: Optimize `build-expression->derivation'.

This reduces the execution time of
"guix build -e '(@ (gnu packages emacs) emacs)' -d" by 6%, from
1.15s to 1.08s.

* guix/derivations.scm (build-expression->derivation): Write the builder
  as UTF-8.
This commit is contained in:
Ludovic Courtès 2013-03-16 17:22:20 +01:00
parent d80855999a
commit 0bb1aa9e05

@ -741,14 +741,21 @@ omitted or is #f, the value of the `%guile-for-build' fluid is used instead."
(unsetenv "LD_LIBRARY_PATH")))
(builder (add-text-to-store store
(string-append name "-guile-builder")
(string-append
(object->string prologue)
(object->string
`(exit
,(match exp
((_ ...)
(remove module-form? exp))
(_ `(,exp))))))
;; Explicitly use UTF-8 for determinism,
;; and also because UTF-8 output is faster.
(with-fluids ((%default-port-encoding
"UTF-8"))
(call-with-output-string
(lambda (port)
(write prologue port)
(write
`(exit
,(match exp
((_ ...)
(remove module-form? exp))
(_ `(,exp))))
port))))
;; The references don't really matter
;; since the builder is always used in