275790 - more ccache friendly NSPR_CFLAGS

Status: RESOLVED WORKSFORME

(Firefox Build System :: General, defect)

Description

[basic]

I'm filing this under firefox because I don't know where to file this. This
affects all mozilla apps. The NSPR_CFLAGS could be more friendly towards people
who build with ccache http://ccache.samba.org/ or other compiler cache systems.

Currently it uses an absolute path, causing many false negative as the absolute
path is different between builds.

For example, I build xulrunner under a 'object-xulrunner' object dir. After that
 I build firefox under 'object-firefox', since they are from the same source I 
expect that there should be some cache hits. However due to the absolute dir
difference in NSPR_CFLAGS it would never hit the cache. I've a patch (coming up)
that makes it slightly better that gets NSPR_CFLAGS to use relative dirs in most
places.

People using source based distros (with ccache enabled) like gentoo should
benefit from this too as they use different path to build each release. This
should increase the likelyhood of hitting the cache specially for minor releases.

Comment 1

[basic]

Attachment: patch

Comment 2

[basic]

Attachment: patch 2

oops attached the wrong file

Comment 3

[Robert O'Callahan (:roc) (email my personal email if necessary)]

Argh, you beat me to it! I've just done exactly this.

Comment 4

[Robert O'Callahan (:roc) (email my personal email if necessary)]

BTW check out my new blog post on this issue. It includes my solution to the
problem of hardlinking across multiple trees.

http://weblogs.mozillazine.org/roc/archives/2005/01/sharing_binarie.html

Comment 5

[Robert O'Callahan (:roc) (email my personal email if necessary)]

checked in. Thanks!

Comment 6

[Justin Lebar (not reading bugmail)]

It appears that this may have regressed.

I'm building on Linux with the following mozconfig:

  . $topsrcdir/browser/config/mozconfig
  ac_add_options --enable-application=browser
  ac_add_options --enable-debug
  ac_add_options --srcdir=..
  mk_add_options MOZ_OBJDIR=@TOPSRCDIR@/obj-@CONFIG_GUESS@

Here's a call to gcc for a random file out of my builds:

c++ -o json.o -c [snip] -I/mnt/mozbuilds/code/ff-4/src/obj-i686-pc-linux-gnu/dist/include/nspr [snip] ../../../js/src/json.cpp

As I understand it, the path to nspr here should be relative, not absolute.

Comment 7

[Justin Lebar (not reading bugmail)]

It also appears that NSS is included with an absolute path.

Comment 8

[Justin Lebar (not reading bugmail)]

This may no longer be necessary, since ccache 3.0pre0 appears to cache builds between different trees as is.

Comment 9

[(not currently active) Ted Mielczarek]

We build NSPR and NSS using the Firefox build system nowadays.