From 226e0c76468e5221b63c4987fb9d0290b6b11693 Mon Sep 17 00:00:00 2001
From: Peter Simons <simons@cryp.to>
Date: Wed, 23 Jun 2010 14:34:59 +0000
Subject: [PATCH] pkgs/stdenv/generic/setup.sh: added support for
 enableParallelBuilding variable

If a build expressions has set "enableParallelBuilding = true", then the
generic builder may utilize more than one CPU core to build that particular
expression. This feature works out of the box for GNU Make. Expressions that
use other build drivers like Boost.Jam or SCons have to specify appropriate
flags such as "-j${NIX_BUILD_CORES}" themselves.

svn path=/nixpkgs/branches/stdenv-updates/; revision=22399
---
 pkgs/stdenv/generic/setup.sh | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/pkgs/stdenv/generic/setup.sh b/pkgs/stdenv/generic/setup.sh
index 5e2fc7b24db..948b6ca3ad6 100644
--- a/pkgs/stdenv/generic/setup.sh
+++ b/pkgs/stdenv/generic/setup.sh
@@ -269,6 +269,23 @@ fi
 export NIX_INDENT_MAKE=1
 
 
+# Normalize the NIX_BUILD_CORES variable. The value might be 0, which
+# means that we're supposed to try and auto-detect the number of
+# available CPU cores at run-time.
+
+if test -z "${NIX_BUILD_CORES:-}"; then
+  NIX_BUILD_CORES="1"
+elif test "$NIX_BUILD_CORES" -le 0; then
+  NIX_BUILD_CORES=$(nproc 2>/dev/null || true)
+  if expr >/dev/null 2>&1 "$NIX_BUILD_CORES" : "^[0-9][0-9]*$"; then
+    :
+  else
+    NIX_BUILD_CORES="1"
+  fi
+fi
+export NIX_BUILD_CORES
+
+
 ######################################################################
 # Misc. helper functions.
 
@@ -603,6 +620,7 @@ buildPhase() {
 
     echo "make flags: $makeFlags ${makeFlagsArray[@]} $buildFlags ${buildFlagsArray[@]}"
     make ${makefile:+-f $makefile} \
+        ${enableParallelBuilding:+-j${NIX_BUILD_CORES} -l${NIX_BUILD_CORES}} \
         $makeFlags "${makeFlagsArray[@]}" \
         $buildFlags "${buildFlagsArray[@]}"
 
@@ -615,6 +633,7 @@ checkPhase() {
 
     echo "check flags: $makeFlags ${makeFlagsArray[@]} $checkFlags ${checkFlagsArray[@]}"
     make ${makefile:+-f $makefile} \
+        ${enableParallelBuilding:+-j${NIX_BUILD_CORES} -l${NIX_BUILD_CORES}} \
         $makeFlags "${makeFlagsArray[@]}" \
         $checkFlags "${checkFlagsArray[@]}" ${checkTarget:-check}