From Rich Paul:

I've noticed that when I compile busybox on my laptop, it compiles more
slowly than one would expect, and although it's a (more-or-less)
multiprocessor system and I use -j5, make never seems to run more than 
one job at a time.

I believe I have found the culprit:  each time a file is compiled, gcc
runs about 5 times.  This is because the $(check_gcc) macros and the
TARGET_ARCH macros are late binding.

The attached patch cuts the compilation time by 66%, from 1.5 minutes to
30 seconds.  Your mileage may very.  These statements have not been
evaluated by the FDA.


git-svn-id: svn://busybox.net/trunk/busybox@10945 69ca8d6d-28ef-0310-b511-8ec308f3f277

1 files changed, 2 insertions, 3 deletions

diff --git a/Rules.mak b/Rules.mak
index 6a2e17ad7..ec03ce011 100644
--- a/Rules.mak
+++ b/Rules.mak
@@ -86,7 +86,7 @@ ARFLAGS=cru
 #--------------------------------------------------------
 export VERSION BUILDTIME TOPDIR HOSTCC HOSTCFLAGS CROSS CC AR AS LD NM STRIP CPP
 ifeq ($(strip $(TARGET_ARCH)),)
-TARGET_ARCH=$(shell $(CC) -dumpmachine | sed -e s'/-.*//' \
+TARGET_ARCH:=$(shell $(CC) -dumpmachine | sed -e s'/-.*//' \
                 -e 's/i.86/i386/' \
                 -e 's/sparc.*/sparc/' \
                 -e 's/arm.*/arm/g' \
@@ -115,8 +115,7 @@ check_gcc=$(shell if $(CC) $(1) -S -o /dev/null -xc /dev/null > /dev/null 2>&1;
 # for OPTIMIZATION...
 
 # use '-Os' optimization if available, else use -O2
-OPTIMIZATION=
-OPTIMIZATION=${call check_gcc,-Os,-O2}
+OPTIMIZATION:=${call check_gcc,-Os,-O2}
 
 # Some nice architecture specific optimizations
 ifeq ($(strip $(TARGET_ARCH)),arm)