mac: Let `gclient runhooks` warn about predictive compilation in xcode3

clang doesn't support predictive compilation, and upstream doesn't want
to add support for it, so tell people to disable predictive compilation in
xcode instead.

Do this every time `gclient runhooks` runs, no matter if clang is
up-to-date or not. Running `xcodebuild -version` sometimes takes a
second or time, but most of the time it's quick, and it's very fast
compared to gyp anyway.

BUG=96315
TEST=`gclient runhooks`, note warning message. Do what message says, `gclient runhooks` again, note that no warning message shows up.
TBR=mark

Review URL: http://codereview.chromium.org/7889022

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@101168 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 26 insertions, 7 deletions

diff --git a/tools/clang/scripts/update.sh b/tools/clang/scripts/update.sh
index f3a261b..20f1ffa 100755
--- a/tools/clang/scripts/update.sh
+++ b/tools/clang/scripts/update.sh
@@ -18,6 +18,8 @@ LLVM_REPO_URL=${LLVM_URL:-http://llvm.org/svn/llvm-project}
 # Die if any command dies.
 set -e
 
+OS="$(uname -s)"
+
 # Parse command line options.
 force_local_build=
 mac_only=
@@ -39,10 +41,27 @@ while [[ $# > 0 ]]; do
   shift
 done
 
-if [ "$mac_only" -a "$(uname -s)" != "Darwin" ]; then
+if [[ -n "$mac_only" ]] && [[ "${OS}" != "Darwin" ]]; then
   exit 0
 fi
 
+# Xcode and clang don't get along when predictive compilation is enabled.
+# http://crbug.com/96315
+if [[ "${OS}" = "Darwin" ]] && xcodebuild -version | grep -q 'Xcode 3.2' ; then
+  XCONF=com.apple.Xcode
+  if [ "$(defaults read "${XCONF}" EnablePredictiveCompilation)" != "0" ]; then
+    echo
+    echo "          HEARKEN!"
+    echo "You're using Xcode3 and you have 'Predictive Compilation' enabled."
+    echo "This does not work well with clang (http://crbug.com/96315)."
+    echo "Disable it in Preferences->Building (lower right), or run"
+    echo "    defaults write ${XCONF} EnablePredictiveCompilation -boolean NO"
+    echo "while Xcode is not running."
+    echo
+  fi
+fi
+
+
 # Since people need to run this script anyway to compile clang, let it check out
 # clang as well if it's not in DEPS, so that people don't have to change their
 # DEPS if they just want to give clang a try.
@@ -51,8 +70,8 @@ CLANG_REVISION=$(grep 'clang_revision":' "${DEPS_FILE}" | egrep -o [[:digit:]]+)
 # Check if there's anything to be done, exit early if not.
 if [ -f "${STAMP_FILE}" ]; then
   PREVIOUSLY_BUILT_REVISON=$(cat "${STAMP_FILE}")
-  if [ -z "$force_local_build" -a \
-       "${PREVIOUSLY_BUILT_REVISON}" = "${CLANG_REVISION}" ]; then
+  if [[ -z "$force_local_build" ]] && \
+       [[ "${PREVIOUSLY_BUILT_REVISON}" = "${CLANG_REVISION}" ]]; then
     echo "Clang already at ${CLANG_REVISION}"
     exit 0
   fi
@@ -66,9 +85,9 @@ if [ -z "$force_local_build" ]; then
   CDS_URL=http://commondatastorage.googleapis.com/chromium-browser-clang
   CDS_FILE="clang-${CLANG_REVISION}.tgz"
   echo Trying to download prebuilt clang
-  if [ "$(uname -s)" = "Linux" ]; then
+  if [ "${OS}" = "Linux" ]; then
     wget "${CDS_URL}/Linux_x64/${CDS_FILE}" || rm -f "${CDS_FILE}"
-  elif [ "$(uname -s)" = "Darwin" ]; then
+  elif [ "${OS}" = "Darwin" ]; then
     curl -L --fail -O "${CDS_URL}/Mac/${CDS_FILE}" || rm -f "${CDS_FILE}"
   fi
   if [ -f "${CDS_FILE}" ]; then
@@ -120,9 +139,9 @@ if [ ! -f ./config.status ]; then
 fi
 
 NUM_JOBS=3
-if [ "$(uname -s)" = "Linux" ]; then
+if [ "${OS}" = "Linux" ]; then
   NUM_JOBS="$(grep -c "^processor" /proc/cpuinfo)"
-elif [ "$(uname -s)" = "Darwin" ]; then
+elif [ "${OS}" = "Darwin" ]; then
   NUM_JOBS="$(sysctl -n hw.ncpu)"
 fi
 make -j"${NUM_JOBS}"