From ff140fa1f13b3c11fde2dcde273b3615c22fc4a5 Mon Sep 17 00:00:00 2001
From: Bill Wendling <isanbard@gmail.com>
Date: Tue, 15 Apr 2008 21:33:52 +0000
Subject: [PATCH] Apple GCC 4.2 builds things differently. It no longer spawns
 a bunch of processes, but requires the project to use -j.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49744 91177308-0d34-0410-b5e6-96231b3b80d8
---
 utils/buildit/build_llvm | 37 +++++++++++++++++++++++++++++++++----
 1 file changed, 33 insertions(+), 4 deletions(-)

diff --git a/utils/buildit/build_llvm b/utils/buildit/build_llvm
index c1df5773ca5..7683f0ad91d 100755
--- a/utils/buildit/build_llvm
+++ b/utils/buildit/build_llvm
@@ -95,10 +95,39 @@ else
     LLVM_VERSION="$LLVM_SUBMIT_VERSION-$LLVM_SUBMIT_SUBVERSION"
 fi
 
-# Note: Don't pass -jN here.  Building universal already has parallelism and we
-# don't want to make the builders hit swap by firing off too many gcc's at the
-# same time.
-make $OPTIMIZE_OPTS UNIVERSAL=1 UNIVERSAL_ARCH="$TARGETS" \
+GCC_VER=`cc --version 2>/dev/null | sed 1q`
+
+if echo "$GCC_VER" | grep GCC > /dev/null; then
+    GCC_VER=`echo $GCC_VER | sed -e 's/.*(GCC) \([0-9.][0-9.]*\).*/\1/'`
+    MAJ_VER=`echo $GCC_VER | sed 's/\..*//'`
+    MIN_VER=`echo $GCC_VER | sed 's/[^.]*\.\([0-9]*\).*/\1/'`
+fi
+
+JOBS_FLAG=""
+
+# Note: If compiling with GCC 4.0, don't pass the -jN flag. Building universal
+# already has parallelism and we don't want to make the builders hit swap by
+# firing off too many gccs at the same time.
+if [ "x$MAJ_VER" != "x4" -o "x$MIN_VER" != "x0" ]; then
+    # Figure out how many make processes to run.
+    SYSCTL=`sysctl -n hw.activecpu`
+
+    # hw.activecpu only available in 10.2.6 and later
+    if [ -z "$SYSCTL" ]; then
+        SYSCTL=`sysctl -n hw.ncpu`
+    fi
+
+    # sysctl -n hw.* does not work when invoked via B&I chroot /BuildRoot.
+    # Builders can default to 2, since even if they are single processor,
+    # nothing else is running on the machine.
+    if [ -z "$SYSCTL" ]; then
+        SYSCTL=2
+    fi
+
+    JOBS_FLAG="-j $SYSCTL"
+fi
+
+make $JOBS_FLAG $OPTIMIZE_OPTS UNIVERSAL=1 UNIVERSAL_ARCH="$TARGETS" \
     LLVM_SUBMIT_VERSION=$LLVM_SUBMIT_VERSION \
     LLVM_SUBMIT_SUBVERSION=$LLVM_SUBMIT_SUBVERSION \
     CXXFLAGS="-DLLVM_VERSION_INFO='\" Apple Build #$LLVM_VERSION\"'"
-- 
2.34.1