_ Git - ldk-c-bindings/blob - genbindings.sh

   1 #!/usr/bin/env bash
   2
   3 set -e
   4 set -x
   5
   6 if [ ! -d "$1/lightning" -o "$2" != "true" -a "$2" != "false" ]; then
   7         echo "USAGE: $0 path-to-rust-lightning allow-std"
   8         echo "allow-std must be either 'true' or 'false' to indicate if we should be built relying on time and pthread support"
   9         exit 1
  10 fi
  11
  12 export LC_ALL=C
  13
  14 # On reasonable systems, we can use realpath here, but OSX is a diva with 20-year-old software.
  15 ORIG_PWD="$(pwd)"
  16 cd "$1"
  17 LIGHTNING_PATH="$(pwd)"
  18 LIGHTNING_GIT="$(git describe --tag --dirty --abbrev=16)"
  19 cd "$ORIG_PWD"
  20
  21 # Generate (and reasonably test) C bindings
  22
  23 # First build the latest c-bindings-gen binary
  24 cd c-bindings-gen && cargo build --release && cd ..
  25
  26 # Then wipe all the existing C bindings (because we're being run in the right directory)
  27 # note that we keep the few manually-generated files first:
  28 mv lightning-c-bindings/src/c_types/mod.rs ./
  29 mv lightning-c-bindings/src/bitcoin ./
  30
  31 # Before we try to sed the Cargo.toml, generate version define tags
  32 # (ignoring any files that we're about to generate)
  33
  34 git checkout lightning-c-bindings/src
  35 git checkout lightning-c-bindings/include
  36 BINDINGS_GIT="$(git describe --tag --dirty --abbrev=16)"
  37 echo -e "#ifndef _LDK_HEADER_VER" > lightning-c-bindings/include/ldk_ver.h
  38 echo -e "static inline int _ldk_strncmp(const char *s1, const char *s2, uint64_t n) {" >> lightning-c-bindings/include/ldk_ver.h
  39 echo -e "\tif (n && *s1 != *s2) return 1;" >> lightning-c-bindings/include/ldk_ver.h
  40 echo -e "\twhile (n && *s1 != 0 && *s2 != 0) {" >> lightning-c-bindings/include/ldk_ver.h
  41 echo -e "\t\ts1++; s2++; n--;" >> lightning-c-bindings/include/ldk_ver.h
  42 echo -e "\t\tif (n && *s1 != *s2) return 1;" >> lightning-c-bindings/include/ldk_ver.h
  43 echo -e "\t}" >> lightning-c-bindings/include/ldk_ver.h
  44 echo -e "\treturn 0;" >> lightning-c-bindings/include/ldk_ver.h
  45 echo -e "}" >> lightning-c-bindings/include/ldk_ver.h
  46 echo -e "" >> lightning-c-bindings/include/ldk_ver.h
  47 echo -e "#define _LDK_HEADER_VER \"$LIGHTNING_GIT\"" >> lightning-c-bindings/include/ldk_ver.h
  48 echo -e "#define _LDK_C_BINDINGS_HEADER_VER \"$BINDINGS_GIT\"" >> lightning-c-bindings/include/ldk_ver.h
  49 echo -e "static inline const char* check_get_ldk_version() {" >> lightning-c-bindings/include/ldk_ver.h
  50 echo -e "\tLDKStr bin_ver = _ldk_get_compiled_version();" >> lightning-c-bindings/include/ldk_ver.h
  51 echo -e "\tif (_ldk_strncmp(_LDK_HEADER_VER, (const char*)bin_ver.chars, bin_ver.len) != 0) {" >> lightning-c-bindings/include/ldk_ver.h
  52 echo -e "\t// Version mismatch, we don't know what we're running!" >> lightning-c-bindings/include/ldk_ver.h
  53 echo -e "\t\treturn 0;" >> lightning-c-bindings/include/ldk_ver.h
  54 echo -e "\t}" >> lightning-c-bindings/include/ldk_ver.h
  55 echo -e "\treturn _LDK_HEADER_VER;" >> lightning-c-bindings/include/ldk_ver.h
  56 echo -e "}" >> lightning-c-bindings/include/ldk_ver.h
  57 echo -e "static inline const char* check_get_ldk_bindings_version() {" >> lightning-c-bindings/include/ldk_ver.h
  58 echo -e "\tLDKStr bin_ver = _ldk_c_bindings_get_compiled_version();" >> lightning-c-bindings/include/ldk_ver.h
  59 echo -e "\tif (_ldk_strncmp(_LDK_C_BINDINGS_HEADER_VER, (const char*)bin_ver.chars, bin_ver.len) != 0) {" >> lightning-c-bindings/include/ldk_ver.h
  60 echo -e "\t// Version mismatch, we don't know what we're running!" >> lightning-c-bindings/include/ldk_ver.h
  61 echo -e "\t\treturn 0;" >> lightning-c-bindings/include/ldk_ver.h
  62 echo -e "\t}" >> lightning-c-bindings/include/ldk_ver.h
  63 echo -e "\treturn _LDK_C_BINDINGS_HEADER_VER;" >> lightning-c-bindings/include/ldk_ver.h
  64 echo -e "}" >> lightning-c-bindings/include/ldk_ver.h
  65 echo -e "#endif /* _LDK_HEADER_VER */" >> lightning-c-bindings/include/ldk_ver.h
  66
  67 rm -rf lightning-c-bindings/src
  68
  69 mkdir -p lightning-c-bindings/src/{c_types,lightning}
  70 mv ./mod.rs lightning-c-bindings/src/c_types/
  71 mv ./bitcoin lightning-c-bindings/src/
  72
  73 # Finally, run the c-bindings-gen binary, building fresh bindings.
  74 OUT="$(pwd)/lightning-c-bindings/src"
  75 OUT_TEMPL="$(pwd)/lightning-c-bindings/src/c_types/derived.rs"
  76 OUT_F="$(pwd)/lightning-c-bindings/include/ldk_rust_types.h"
  77 OUT_CPP="$(pwd)/lightning-c-bindings/include/lightningpp.hpp"
  78 BIN="$(pwd)/c-bindings-gen/target/release/c-bindings-gen"
  79
  80 HOST_PLATFORM="$(rustc --version --verbose | grep "host:")"
  81
  82 function add_crate() {
  83         pushd "$LIGHTNING_PATH/$1"
  84         RUSTC_BOOTSTRAP=1 cargo rustc --profile=check $3 -- -Zunstable-options --pretty=expanded > /tmp/$1-crate-source.txt
  85         popd
  86         if [ "$HOST_PLATFORM" = "host: x86_64-apple-darwin" ]; then
  87                 sed -i".original" "1i\\
  88 pub mod $2 {
  89 " /tmp/$1-crate-source.txt
  90         else
  91                 sed -i "1ipub mod $2 {\n" /tmp/$1-crate-source.txt
  92         fi
  93         echo "}" >> /tmp/$1-crate-source.txt
  94         cat /tmp/$1-crate-source.txt >> /tmp/crate-source.txt
  95         rm /tmp/$1-crate-source.txt
  96         if [ "$HOST_PLATFORM" = "host: x86_64-apple-darwin" ]; then
  97                 # OSX sed is for some reason not compatible with GNU sed
  98                 sed -E -i '' 's|#?'$1' = \{ .*|'$1' = \{ path = "'"$LIGHTNING_PATH"'/'$1'" '"$4"' }|' lightning-c-bindings/Cargo.toml
  99         else
 100                 sed -E -i 's|#?'$1' = \{ .*|'$1' = \{ path = "'"$LIGHTNING_PATH"'/'$1'" '"$4"' }|' lightning-c-bindings/Cargo.toml
 101         fi
 102 }
 103
 104 function drop_crate() {
 105         if [ "$HOST_PLATFORM" = "host: x86_64-apple-darwin" ]; then
 106                 # OSX sed is for some reason not compatible with GNU sed
 107                 sed -E -i '' 's|'$1' = \{ (.*)|#'$1' = \{ \1|' lightning-c-bindings/Cargo.toml
 108         else
 109                 sed -E -i 's|'$1' = \{ (.*)|#'$1' = \{ \1|' lightning-c-bindings/Cargo.toml
 110         fi
 111 }
 112
 113 echo > /tmp/crate-source.txt
 114 if [ "$2" = "true" ]; then
 115         add_crate lightning lightning --features=allow_wallclock_use ', features = ["allow_wallclock_use"]'
 116         add_crate "lightning-persister" "lightning_persister"
 117         add_crate "lightning-background-processor" "lightning_background_processor"
 118 else
 119         add_crate lightning lightning
 120         drop_crate "lightning-persister"
 121         drop_crate "lightning-background-processor"
 122 fi
 123 add_crate "lightning-invoice" "lightning_invoice"
 124
 125 cat /tmp/crate-source.txt | RUST_BACKTRACE=1 "$BIN" "$OUT/" "$OUT_TEMPL" "$OUT_F" "$OUT_CPP"
 126
 127 echo -e '#[no_mangle]' >> lightning-c-bindings/src/version.rs
 128 echo -e 'pub extern "C" fn _ldk_get_compiled_version() -> crate::c_types::Str {' >> lightning-c-bindings/src/version.rs
 129 echo -e '\t"'"$LIGHTNING_GIT"'".into()' >> lightning-c-bindings/src/version.rs
 130 echo -e '}' >> lightning-c-bindings/src/version.rs
 131 echo -e '#[no_mangle]' >> lightning-c-bindings/src/version.rs
 132 echo -e 'pub extern "C" fn _ldk_c_bindings_get_compiled_version() -> crate::c_types::Str {' >> lightning-c-bindings/src/version.rs
 133 echo -e '\t"'"$BINDINGS_GIT"'".into()' >> lightning-c-bindings/src/version.rs
 134 echo -e '}' >> lightning-c-bindings/src/version.rs
 135
 136 # Set path to include our rustc wrapper as well as cbindgen
 137 export LDK_RUSTC_PATH="$(which rustc)"
 138 PATH="$(pwd)/deterministic-build-wrappers:$PATH:~/.cargo/bin"
 139 # Now cd to lightning-c-bindings, build the generated bindings, and call cbindgen to build a C header file
 140 cd lightning-c-bindings
 141
 142 # Set up CFLAGS and RUSTFLAGS vars appropriately for building libsecp256k1 and demo apps...
 143 BASE_CFLAGS="" # CFLAGS for libsecp256k1
 144 LOCAL_CFLAGS="" # CFLAGS for demo apps
 145 BASE_RUSTFLAGS="" # RUSTFLAGS
 146
 147 # Remap paths so that our builds are deterministic
 148 BASE_RUSTFLAGS="--remap-path-prefix $LIGHTNING_PATH=rust-lightning --remap-path-prefix $(pwd)=ldk-c-bindings --remap-path-prefix $HOME/.cargo="
 149
 150 # If the C compiler supports it, also set -ffile-prefix-map
 151 echo "int main() {}" > genbindings_path_map_test_file.c
 152 clang -o /dev/null -ffile-prefix-map=$HOME/.cargo= genbindings_path_map_test_file.c > /dev/null 2>&1 &&
 153 export BASE_CFLAGS="-ffile-prefix-map=$HOME/.cargo="
 154
 155 BASE_CFLAGS="$BASE_CFLAGS -frandom-seed=42"
 156 LOCAL_CFLAGS="-Wall -Wno-nullability-completeness -pthread -Iinclude/"
 157
 158 if [ "$HOST_PLATFORM" = "host: x86_64-apple-darwin" ]; then
 159         LOCAL_CFLAGS="$LOCAL_CFLAGS -isysroot$(xcrun --show-sdk-path)"
 160         BASE_CFLAGS="$BASE_CFLAGS -isysroot$(xcrun --show-sdk-path)"
 161         # Targeting aarch64 appears to be supported only starting with Big Sur, so check it before use
 162         clang -o /dev/null -target=aarch64-apple-darwin -mcpu=apple-a14 genbindings_path_map_test_file.c > /dev/null 2>&1 &&
 163         export CFLAGS_aarch64_apple_darwin="$BASE_CFLAGS -target=aarch64-apple-darwin -mcpu=apple-a14"
 164 fi
 165
 166 rm genbindings_path_map_test_file.c
 167
 168 ENV_TARGET=$(rustc --version --verbose | grep host | awk '{ print $2 }' | sed 's/-/_/g')
 169 case "$ENV_TARGET" in
 170         "x86_64"*)
 171                 export RUSTFLAGS="$BASE_RUSTFLAGS -C target-cpu=sandybridge"
 172                 export CFLAGS_$ENV_TARGET="$BASE_CFLAGS -march=sandybridge -mcpu=sandybridge -mtune=sandybridge"
 173                 ;;
 174         *)
 175                 # Assume this isn't targeted at another host and build for the host's CPU.
 176                 export RUSTFLAGS="$BASE_RUSTFLAGS -C target-cpu=native"
 177                 export CFLAGS_$ENV_TARGET="$BASE_CFLAGS -mcpu=native"
 178                 ;;
 179 esac
 180
 181 cargo build
 182 if [ "$CFLAGS_aarch64_apple_darwin" != "" ]; then
 183         RUSTFLAGS="$BASE_RUSTFLAGS -C target-cpu=apple-a14" cargo build --target aarch64-apple-darwin
 184 fi
 185 cbindgen -v --config cbindgen.toml -o include/lightning.h >/dev/null 2>&1
 186
 187 # cbindgen is relatively braindead when exporting typedefs -
 188 # it happily exports all our typedefs for private types, even with the
 189 # generics we specified in C mode! So we drop all those types manually here.
 190 if [ "$HOST_PLATFORM" = "host: x86_64-apple-darwin" ]; then
 191         # OSX sed is for some reason not compatible with GNU sed
 192         sed -i '' 's/typedef LDKnative.*Import.*LDKnative.*;//g' include/lightning.h
 193
 194         # stdlib.h doesn't exist in clang's wasm sysroot, and cbindgen
 195         # doesn't actually use it anyway, so drop the import.
 196         sed -i '' 's/#include <stdlib.h>/#include <ldk_rust_types.h>/g' include/lightning.h
 197 else
 198         sed -i 's/typedef LDKnative.*Import.*LDKnative.*;//g' include/lightning.h
 199
 200         # stdlib.h doesn't exist in clang's wasm sysroot, and cbindgen
 201         # doesn't actually use it anyway, so drop the import.
 202         sed -i 's/#include <stdlib.h>/#include <ldk_rust_types.h>/g' include/lightning.h
 203 fi
 204
 205 # Finally, sanity-check the generated C and C++ bindings with demo apps:
 206 # Naively run the C demo app:
 207 gcc $LOCAL_CFLAGS -Wall -g -pthread demo.c target/debug/libldk.a -ldl
 208 ./a.out
 209
 210 # And run the C++ demo app in valgrind to test memory model correctness and lack of leaks.
 211 g++ $LOCAL_CFLAGS -std=c++11 -Wall -g -pthread demo.cpp -Ltarget/debug/ -lldk -ldl
 212 if [ -x "`which valgrind`" ]; then
 213         LD_LIBRARY_PATH=target/debug/ valgrind --error-exitcode=4 --memcheck:leak-check=full --show-leak-kinds=all ./a.out
 214         echo
 215 else
 216         echo "WARNING: Please install valgrind for more testing"
 217 fi
 218
 219 # Test a statically-linked C++ version, tracking the resulting binary size and runtime
 220 # across debug, LTO, and cross-language LTO builds (using the same compiler each time).
 221 clang++ $LOCAL_CFLAGS -std=c++11 demo.cpp target/debug/libldk.a -ldl
 222 strip ./a.out
 223 echo " C++ Bin size and runtime w/o optimization:"
 224 ls -lha a.out
 225 time ./a.out > /dev/null
 226
 227 # Then, check with memory sanitizer, if we're on Linux and have rustc nightly
 228 if [ "$HOST_PLATFORM" = "host: x86_64-unknown-linux-gnu" ]; then
 229         if cargo +nightly --version >/dev/null 2>&1; then
 230                 LLVM_V=$(rustc +nightly --version --verbose | grep "LLVM version" | awk '{ print substr($3, 0, 2); }')
 231                 if [ -x "$(which clang-$LLVM_V)" ]; then
 232                         cargo +nightly clean
 233                         cargo +nightly rustc -Zbuild-std --target x86_64-unknown-linux-gnu -v -- -Zsanitizer=memory -Zsanitizer-memory-track-origins -Cforce-frame-pointers=yes
 234                         mv target/x86_64-unknown-linux-gnu/debug/libldk.* target/debug/
 235
 236                         # Sadly, std doesn't seem to compile into something that is memsan-safe as of Aug 2020,
 237                         # so we'll always fail, not to mention we may be linking against git rustc LLVM which
 238                         # may differ from clang-llvm, so just allow everything here to fail.
 239                         set +e
 240
 241                         # First the C demo app...
 242                         clang-$LLVM_V $LOCAL_CFLAGS -fsanitize=memory -fsanitize-memory-track-origins -g demo.c target/debug/libldk.a -ldl
 243                         ./a.out
 244
 245                         # ...then the C++ demo app
 246                         clang++-$LLVM_V $LOCAL_CFLAGS -std=c++11 -fsanitize=memory -fsanitize-memory-track-origins -g demo.cpp target/debug/libldk.a -ldl
 247                         ./a.out >/dev/null
 248
 249                         # restore exit-on-failure
 250                         set -e
 251                 else
 252                         echo "WARNING: Can't use memory sanitizer without clang-$LLVM_V"
 253                 fi
 254         else
 255                 echo "WARNING: Can't use memory sanitizer without rustc nightly"
 256         fi
 257 else
 258         echo "WARNING: Can't use memory sanitizer on non-Linux, non-x86 platforms"
 259 fi
 260
 261 RUSTC_LLVM_V=$(rustc --version --verbose | grep "LLVM version" | awk '{ print substr($3, 0, 2); }' | tr -d '.')
 262
 263 if [ "$HOST_PLATFORM" = "host: x86_64-apple-darwin" ]; then
 264         # Apple is special, as always, and their versions of clang aren't
 265         # compatible with upstream LLVM.
 266         if [ "$(clang --version | grep 'Apple clang')" != "" ]; then
 267                 echo "Apple clang isn't compatible with upstream clang, install upstream clang"
 268                 CLANG_LLVM_V="0"
 269         else
 270                 CLANG_LLVM_V=$(clang --version | head -n1 | awk '{ print substr($4, 0, 2); }' | tr -d '.')
 271         fi
 272 else
 273         CLANG_LLVM_V=$(clang --version | head -n1 | awk '{ print substr($4, 0, 2); }' | tr -d '.')
 274 fi
 275
 276 if [ "$CLANG_LLVM_V" = "$RUSTC_LLVM_V" ]; then
 277         CLANG=clang
 278         CLANGPP=clang++
 279 elif [ "$(which clang-$RUSTC_LLVM_V)" != "" ]; then
 280         CLANG="$(which clang-$RUSTC_LLVM_V)"
 281         CLANGPP="$(which clang++-$RUSTC_LLVM_V || echo clang++)"
 282         if [ "$($CLANG --version)" != "$($CLANGPP --version)" ]; then
 283                 echo "$CLANG and $CLANGPP are not the same version of clang!"
 284                 unset CLANG
 285                 unset CLANGPP
 286         fi
 287 fi
 288
 289 if [ "$CLANG" != "" -a "$CLANGPP" = "" ]; then
 290         echo "WARNING: It appears you have a clang-$RUSTC_LLVM_V but not clang++-$RUSTC_LLVM_V. This is common, but leaves us unable to compile C++ with LLVM $RUSTC_LLVM_V"
 291         echo "You should create a symlink called clang++-$RUSTC_LLVM_V pointing to $CLANG in $(dirname $CLANG)"
 292 fi
 293
 294 # Finally, if we're on OSX or on Linux, build the final debug binary with address sanitizer (and leave it there)
 295 if [ "$HOST_PLATFORM" = "host: x86_64-unknown-linux-gnu" -o "$HOST_PLATFORM" = "host: x86_64-apple-darwin" ]; then
 296         if [ "$CLANGPP" != "" ]; then
 297                 if [ "$HOST_PLATFORM" = "host: x86_64-apple-darwin" ]; then
 298                         # OSX sed is for some reason not compatible with GNU sed
 299                         sed -i .bk 's/,"cdylib"]/]/g' Cargo.toml
 300                 else
 301                         sed -i.bk 's/,"cdylib"]/]/g' Cargo.toml
 302                 fi
 303                 if [ "$CFLAGS_aarch64_apple_darwin" != "" ]; then
 304                         RUSTFLAGS="$BASE_RUSTFLAGS -C target-cpu=apple-a14" RUSTC_BOOTSTRAP=1 cargo rustc --target aarch64-apple-darwin -v -- -Zsanitizer=address -Cforce-frame-pointers=yes || ( mv Cargo.toml.bk Cargo.toml; exit 1)
 305                 fi
 306                 RUSTC_BOOTSTRAP=1 cargo rustc -v -- -Zsanitizer=address -Cforce-frame-pointers=yes || ( mv Cargo.toml.bk Cargo.toml; exit 1)
 307                 mv Cargo.toml.bk Cargo.toml
 308
 309                 # First the C demo app...
 310                 $CLANG $LOCAL_CFLAGS -fsanitize=address -g demo.c target/debug/libldk.a -ldl
 311                 ASAN_OPTIONS='detect_leaks=1 detect_invalid_pointer_pairs=1 detect_stack_use_after_return=1' ./a.out
 312
 313                 # ...then the C++ demo app
 314                 $CLANGPP $LOCAL_CFLAGS -std=c++11 -fsanitize=address -g demo.cpp target/debug/libldk.a -ldl
 315                 ASAN_OPTIONS='detect_leaks=1 detect_invalid_pointer_pairs=1 detect_stack_use_after_return=1' ./a.out >/dev/null
 316         else
 317                 echo "WARNING: Please install clang-$RUSTC_LLVM_V and clang++-$RUSTC_LLVM_V to build with address sanitizer"
 318         fi
 319 else
 320         echo "WARNING: Can't use address sanitizer on non-Linux, non-OSX non-x86 platforms"
 321 fi
 322
 323 # Now build with LTO on on both C++ and rust, but without cross-language LTO:
 324 # Clear stale release build artifacts from previous runs
 325 cargo clean --release
 326 CARGO_PROFILE_RELEASE_LTO=true cargo rustc -v --release -- -C lto
 327 clang++ $LOCAL_CFLAGS -std=c++11 -flto -O2 demo.cpp target/release/libldk.a -ldl
 328
 329 strip ./a.out
 330 echo "C++ Bin size and runtime with only RL (LTO) optimized:"
 331 ls -lha a.out
 332 time ./a.out > /dev/null
 333
 334 if [ "$HOST_PLATFORM" != "host: x86_64-apple-darwin" -a "$CLANGPP" != "" ]; then
 335         # If we can use cross-language LTO, use it for building C dependencies (i.e. libsecp256k1) as well
 336         export CC="$CLANG"
 337         # The cc-rs crate tries to force -fdata-sections and -ffunction-sections on, which
 338         # breaks -fembed-bitcode, so we turn off cc-rs' default flags and specify exactly
 339         # what we want here.
 340         export CFLAGS_$ENV_TARGET="$BASE_CFLAGS -fPIC -fembed-bitcode -march=sandybridge"
 341         export CRATE_CC_NO_DEFAULTS=true
 342 fi
 343
 344 if [ "$2" = "false" -a "$(rustc --print target-list | grep wasm32-wasi)" != "" ]; then
 345         # Test to see if clang supports wasm32 as a target (which is needed to build rust-secp256k1)
 346         echo "int main() {}" > genbindings_wasm_test_file.c
 347         if clang -nostdlib -o /dev/null --target=wasm32-wasi -Wl,--no-entry genbindings_wasm_test_file.c > /dev/null 2>&1; then
 348                 # And if it does, build a WASM binary without capturing errors
 349                 export CFLAGS_wasm32_wasi="$BASE_CFLAGS -target wasm32"
 350                 cargo rustc -v --target=wasm32-wasi
 351                 export CFLAGS_wasm32_wasi="$BASE_CFLAGS -target wasm32 -Os"
 352                 CARGO_PROFILE_RELEASE_LTO=true cargo rustc -v --release --target=wasm32-wasi -- -C embed-bitcode=yes -C opt-level=s -C linker-plugin-lto -C lto
 353         else
 354                 echo "Cannot build WASM lib as clang does not seem to support the wasm32-wasi target"
 355         fi
 356         rm genbindings_wasm_test_file.c
 357 fi
 358
 359 if [ "$CFLAGS_aarch64_apple_darwin" != "" ]; then
 360         RUSTFLAGS="$BASE_RUSTFLAGS -C target-cpu=apple-a14" CARGO_PROFILE_RELEASE_LTO=true cargo rustc -v --release --target aarch64-apple-darwin -- -C lto
 361 fi
 362
 363 if [ "$HOST_PLATFORM" != "host: x86_64-apple-darwin" -a "$CLANGPP" != "" ]; then
 364         # Finally, test cross-language LTO. Note that this will fail if rustc and clang++
 365         # build against different versions of LLVM (eg when rustc is installed via rustup
 366         # or Ubuntu packages). This should work fine on Distros which do more involved
 367         # packaging than simply shipping the rustup binaries (eg Debian should Just Work
 368         # here).
 369         export CFLAGS_$ENV_TARGET="$BASE_CFLAGS -O3 -fPIC -fembed-bitcode -march=sandybridge"
 370         # Rust doesn't recognize CFLAGS changes, so we need to clean build artifacts
 371         cargo clean --release
 372         CARGO_PROFILE_RELEASE_LTO=true cargo rustc -v --release -- -C linker-plugin-lto -C lto -C link-arg=-fuse-ld=lld
 373         $CLANGPP $LOCAL_CFLAGS -flto -fuse-ld=lld -O2 demo.cpp target/release/libldk.a -ldl
 374         strip ./a.out
 375         echo "C++ Bin size and runtime with cross-language LTO:"
 376         ls -lha a.out
 377         time ./a.out > /dev/null
 378 else
 379         echo "WARNING: Building with cross-language LTO is not avilable on OSX or without clang-$RUSTC_LLVM_V"
 380 fi