[llvm-build] Add -j option

Allow the user to override the number of CPUs used for building LLVM. The
default remains unchanged, so if you're not going to use the -j flag it won't
affect you.

Change-Id: I2491274a629a505744a80625381fb2c47bafd4da

1 files changed, 10 insertions, 4 deletions

diff --git a/helpers/llvm-build b/helpers/llvm-build
index 7e00b2b..5ef0662 100755
--- a/helpers/llvm-build
+++ b/helpers/llvm-build
@@ -11,14 +11,14 @@
 safe_run verify_env
 
 ## CMD line options and defaults
-CPUs=`grep -c proc /proc/cpuinfo`
+PARALLEL=-j`grep -c proc /proc/cpuinfo`
 build_dir=$LLVM_BLD
 install_dir=$LLVM_INSTALL
 build_type=Release
 shared=
 targets=
 prog=`basename $0`
-syntax="Syntax: $prog [targets]"
+syntax="Syntax: $prog [-jN] [targets]"
 update=false
 check=false
 master=false
@@ -62,14 +62,20 @@ if [ ! -f build.ninja ] && [ ! -f Makefile ]; then
             $targets $shared
 fi
 
+## Allow the user to override the number of CPUs used with -jN
+if [[ $1 =~ -j[0-9]+ ]]; then
+  PARALLEL=$1
+  shift
+fi
+
 ## Build
 if [ "$1" == "" ]; then
   echo " + Building LLVM"
-  safe_run $make -j$CPUs
+  safe_run $make $PARALLEL
 else
   for target in "$@"; do
     echo " + Running $target"
-    safe_run $make -j$CPUs $target
+    safe_run $make $PARALLEL $target
   done
 fi