diff --git a/tools/check_builds.sh b/tools/check_builds.sh
new file mode 100755
index 0000000..14dfec6
--- /dev/null
+++ b/tools/check_builds.sh
@@ -0,0 +1,67 @@
+# Copyright (C) 2009 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the 'License');
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an 'AS IS' BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+#
+# Usage:
+#
+# Source this file into your environment.  Then:
+#
+#    $ golden_builds sdk-sdk generic-eng generic-userdebug dream-eng
+# 
+# will build a set of combos.  This might take a while.  Then you can
+# go make changes, and run:
+#
+#    $ check_builds sdk-sdk generic-eng generic-userdebug dream-eng
+#
+# Go get dinner, and when you get back, there will be a file
+# test-builds/sizes.html that has a pretty chart of which files are
+# in which tree, and how big they are.  In that chart, cells for files
+# that are missing are red, and rows where the file sizes are not all
+# the same will be blue.
+#
+
+TEST_BUILD_DIR=test-builds
+
+function do_builds
+{
+    PREFIX=$1
+    shift
+    while [ -n "$1" ]
+    do
+        rm -rf $TEST_BUILD_DIR/$PREFIX-$1
+        make -j6 PRODUCT-$1 dist DIST_DIR=$TEST_BUILD_DIR/$PREFIX-$1
+        if [ $? -ne 0 ] ; then
+            echo FAILED
+            return
+        fi
+        shift
+    done
+}
+
+function golden_builds
+{
+    rm -rf $TEST_BUILD_DIR/golden-* $TEST_BUILD_DIR/dist-*
+    do_builds golden "$@"
+}
+
+function check_builds
+{
+    rm -rf $TEST_BUILD_DIR/dist-*
+    do_builds dist "$@"
+    build/tools/compare_fileslist.py \
+            $TEST_BUILD_DIR/golden-*/installed-files.txt \
+            $TEST_BUILD_DIR/dist-*/installed-files.txt \
+        > $TEST_BUILD_DIR/sizes.html
+}
+