Add support for using local binary packages.

This CL adds the --reuse_pkgs_from_local_boards flag to setup_board and
build_packages. With this flag, binary packages are shared between boards
that are built locally, so that the total time required to build several
boards is reduced.

This flag is only useful when you are not able to use remote binary packages,
since remote binary packages are usually more up to date than anything you have
locally. For this reason it is typically only used by buildbots which build
multiple similar full builds on the same machine.

BUG=chromium-os:26232
TEST=Test build using only local binary packages from a different
     board.
CQ-DEPEND=I0353dd34f63f1b5c9c1a08882322279c6c4d82f5

Change-Id: I8a1d2687bd0d177de4464a80703b8b5a0b6c9f52
Reviewed-on: https://gerrit.chromium.org/gerrit/15775
Commit-Ready: David James <davidjames@chromium.org>
Reviewed-by: David James <davidjames@chromium.org>
Tested-by: David James <davidjames@chromium.org>

build_packages

@@ -73,6 +73,14 @@ DEFINE_boolean oldchromebinary "${FLAGS_FALSE}" \
 DEFINE_boolean skip_toolchain_update "${FLAGS_FALSE}" \
   "Don't update toolchain automatically."
 
+# The --reuse_pkgs_from_local_boards flag tells Portage to share binary
+# packages between boards that are built locally, so that the total time
+# required to build several boards is reduced. This flag is only useful
+# when you are not able to use remote binary packages, since remote binary
+# packages are usually more up to date than anything you have locally.
+DEFINE_boolean reuse_pkgs_from_local_boards $FLAGS_FALSE \
+  "Bootstrap from local packages instead of remote packages."
+
 
 # Parse command line
 FLAGS_HELP="usage: $0 [flags]"
@@ -103,7 +111,8 @@ if [[ -n "${EXTRA_BOARD_FLAGS}" ]]; then
   EMERGE_BOARD_CMD="${EMERGE_BOARD_CMD} ${EXTRA_BOARD_FLAGS}"
 fi
 
-if [[ "${FLAGS_usepkg}" -eq "${FLAGS_TRUE}" ]]; then
+if [[ "${FLAGS_usepkg}" -eq "${FLAGS_TRUE}" ||
+      "${FLAGS_reuse_pkgs_from_local_boards}" -eq "${FLAGS_TRUE}" ]]; then
   # Use binary packages. Include all build-time dependencies,
   # so as to avoid unnecessary differences between source
   # and binary builds.
@@ -135,6 +144,9 @@ fi
 if [[ "${FLAGS_jobs}" -ne -1 ]]; then
   UPDATE_ARGS+=" --jobs=${FLAGS_jobs}"
 fi
+if [ "${FLAGS_reuse_pkgs_from_local_boards}" -eq "${FLAGS_TRUE}" ]; then
+  UPDATE_ARGS+=" --reuse_pkgs_from_local_boards"
+fi
 if [ "${FLAGS_skip_toolchain_update}" -eq "${FLAGS_TRUE}" ]; then
   UPDATE_ARGS+=" --skip_toolchain_update"
 fi

setup_board

@@ -74,6 +74,15 @@ DEFINE_boolean skip_chroot_upgrade $FLAGS_FALSE \
 This should only be called by version hook scripts that need to call \
 setup_board."
 
+# The --reuse_pkgs_from_local_boards flag tells Portage to share binary
+# packages between boards that are built locally, so that the total time
+# required to build several boards is reduced. This flag is only useful
+# when you are not able to use remote binary packages, since remote binary
+# packages are usually more up to date than anything you have locally.
+DEFINE_boolean reuse_pkgs_from_local_boards $FLAGS_FALSE \
+  "Bootstrap from local packages instead of remote packages."
+
+
 # builds wrappers like equery-arm-generic.
 # args:
 #   $1:  command to wrap
@@ -394,7 +403,15 @@ print_board_make_conf() {
   echo
 }
 
-print_board_binhost_config() {
+print_binhost_config() {
+  if [ "$1" == "--local" ]; then
+    cros_generate_local_binhosts --board "${BOARD_VARIANT}"
+    echo 'PORTAGE_BINHOST="$LOCAL_BINHOST"'
+    return 0
+  elif [ $# -ne 0 ]; then
+    die "Invalid arguments for print_binhost_config: $@"
+  fi
+
   local binhost_dir="$CHROMIUMOS_OVERLAY/chromeos/binhost/target"
   local preflight_binhost="$binhost_dir/$BOARD-PREFLIGHT_BINHOST.conf"
   local chrome_binhost_suffix="LATEST_RELEASE_CHROME_BINHOST.conf"
@@ -452,6 +469,14 @@ EOF
   fi
 }
 
+print_board_binhost_config() {
+  if [ "${FLAGS_reuse_pkgs_from_local_boards}" -eq "${FLAGS_TRUE}" ]; then
+    print_binhost_config --local
+  else
+    print_binhost_config
+  fi
+}
+
 # Parse command line flags
 FLAGS "$@" || exit 1
 eval set -- "${FLAGS_ARGV}"
@@ -571,8 +596,8 @@ if [ -d "$BOARD_ROOT" ] ; then
     sudo rm -rf $TEMP_DIR &
   else
     if ! $HOST_BOARD; then
-      print_board_make_conf | sudo_clobber $BOARD_ETC/make.conf.board
-      print_board_binhost_config | sudo_append $BOARD_ETC/make.conf.board
+      { print_board_make_conf; print_board_binhost_config; } | \
+        sudo_clobber $BOARD_ETC/make.conf.board
     fi
     if [[ $FLAGS_quiet -eq $FLAGS_FALSE ]]; then
       warn "Board output directory '$BOARD_ROOT' already exists."
@@ -631,7 +656,6 @@ if ! ${HOST_BOARD}; then
   sudo ln -sf "${CHROMIUMOS_CONFIG}/make.conf.${ARCH}-target" \
     "${BOARD_ETC}/make.conf"
   print_board_make_conf | sudo_clobber $BOARD_ETC/make.conf.board
-  print_board_binhost_config | sudo_append $BOARD_ETC/make.conf.board
 
   # We install the toolchain related bits after the BOARD_ROOT, BOARD_PROFILE
   # and BOARD_ETC directories have been created.
@@ -728,15 +752,23 @@ if ${HOST_BOARD}; then
   sudo find $BOARD_ROOT -type f -name '*.la' | xargs sudo \
       sed -i -e "s|$BOARD_ROOT/|/|g"
 else
+  # Now that the portageq-* wrappers have been created, we can add the binhost
+  # config to make.conf.board.
+  print_board_binhost_config | sudo_append $BOARD_ETC/make.conf.board
+
   #
   # Emerge the kernel headers into the board build root.
   #
-  EMERGE_FLAGS="--select --quiet"
-  if [[ $FLAGS_usepkg -eq $FLAGS_TRUE ]]; then
-    EMERGE_FLAGS+=" --getbinpkg --usepkg"
+  KERNEL_EMERGE_FLAGS="--select --quiet"
+  if [[ "${FLAGS_usepkg}" -eq "${FLAGS_TRUE}" ||
+        "${FLAGS_reuse_pkgs_from_local_boards}" -eq "${FLAGS_TRUE}" ]]; then
+    KERNEL_EMERGE_FLAGS+=" --getbinpkg --usepkg"
   fi
 
-  sudo -E "${EMERGE_WRAPPER}" ${EMERGE_FLAGS} chromeos-base/kernel-headers
+  sudo -E "${EMERGE_WRAPPER}" ${KERNEL_EMERGE_FLAGS} \
+    chromeos-base/kernel-headers
+
+  unset KERNEL_EMERGE_FLAGS
 fi
 
 if [ $FLAGS_default -eq $FLAGS_TRUE ] ; then