fix osx compilation, test clang binary

Summary:
It turns out that "-s" breaks the osx build. Do not rely on that for stripping
but still pass it when supported as it will be cheaper to copy over
already-stripped libraries and binaries.

Add console messages before long silent steps.

Test the built and the installed clang to make sure we don't proceed
successfully if something went wrong.

Test Plan: `./clang/setup.sh`

Reviewers: ryanrhee, akotulski

Reviewed By: ryanrhee, akotulski

Subscribers: mathieubaudet

Differential Revision: https://phabricator.intern.facebook.com/D4635124

Tasks: 16339929

Signature: t1:4635124:1488381259:c5cfd2e8e358ecf5861ae8ee19a69d572dc7ecb7

clang/setup.sh

@@ -88,8 +88,6 @@ platform=`uname`
 CMAKE_ARGS=(
   -DCMAKE_INSTALL_PREFIX="$CLANG_PREFIX"
   -DCMAKE_BUILD_TYPE=Release
-  -DCMAKE_C_FLAGS="$CMAKE_C_FLAGS -s"
-  -DCMAKE_CXX_FLAGS="$CMAKE_CXX_FLAGS -s"
   -DLLVM_ENABLE_ASSERTIONS=Off
   -DLLVM_ENABLE_EH=On
   -DLLVM_ENABLE_RTTI=On
@@ -99,15 +97,19 @@ if [ "$platform" = "Darwin" ]; then
     CMAKE_ARGS+=(
       -DLLVM_ENABLE_LIBCXX=On
       -DCMAKE_SHARED_LINKER_FLAGS="$CMAKE_SHARED_LINKER_FLAGS"
+      # adding -s to the C{,XX} flags breaks the compilation on osx
+      -DCMAKE_C_FLAGS="$CMAKE_C_FLAGS"
+      -DCMAKE_CXX_FLAGS="$CMAKE_CXX_FLAGS"
     )
 else
     CMAKE_ARGS+=(
       -DCMAKE_SHARED_LINKER_FLAGS="-lstdc++ $CMAKE_SHARED_LINKER_FLAGS"
+      -DCMAKE_C_FLAGS="-s $CMAKE_C_FLAGS"
+      -DCMAKE_CXX_FLAGS="-s $CMAKE_CXX_FLAGS"
     )
 fi
 
 # start the installation
-echo "Installing clang..."
 if [ -n "$CLANG_TMP_DIR" ]; then
     TMP=$CLANG_TMP_DIR
 else
@@ -119,6 +121,7 @@ if tar --version | grep -q 'GNU'; then
     # GNU tar is too verbose if the tarball was created on MacOS
     QUIET_TAR="--warning=no-unknown-keyword"
 fi
+echo "unpacking '$CLANG_SRC'..."
 tar --extract $QUIET_TAR --file "$CLANG_SRC"
 
 mkdir build
@@ -131,11 +134,27 @@ cmake -G "Unix Makefiles" ../llvm "${CMAKE_ARGS[@]}" $CLANG_CMAKE_ARGS
 
 JOBS="$(getconf _NPROCESSORS_ONLN 2>/dev/null || echo 1)"
 
-make -j $JOBS && make -j $JOBS install
+make -j $JOBS
+
+echo "testing clang build"
+./bin/clang --version
+
+make -j $JOBS install
 
 popd # build
 popd # $TMP
 
+# brutally strip everything, ignore errors
+set +e
+find "$CLANG_PREFIX"/{bin,lib} -type f \
+  \( -name '*.so' -o -name '*.so.*' -o -name '*.a' \) \
+  -exec strip -x \{\} \+
+set -e
+
+echo "testing installed clang"
+"$CLANG_PREFIX"/bin/clang --version
+
+echo "deleting temp dir '$CLANG_TMP_DIR'..."
 if [ -n "$CLANG_TMP_DIR" ]; then
     rm -rf "$TMP/*"
 else