Merge pull request #6 from TheBlueMatt/2021-03-deterministic-bins

Make build output deterministic by remapping paths

diff --git a/deterministic-build-wrappers/rustc b/deterministic-build-wrappers/rustc
new file mode 100755 (executable)
index 0000000..2f35677
--- /dev/null
+++ b/deterministic-build-wrappers/rustc
@@ -0,0 +1,30 @@
+#!/bin/bash
+# rustc calculates a unique metadata tag to mangle symbols which includes the
+# actual path to the crate. This breaks our deterministic builds as we depend
+# on a copy of rust-lightning via a path. We insert this shim between cargo and
+# rustc and edit the metadata tag for rust-lightning.
+# While we could just set RUSTFLAGS="-C metadata=42", this would break if we
+# ever (indirectly) depend on multiple versions of the same crate.
+args=("$@")
+IS_LIGHTNING=false
+for ((i=0; i<"${#args[@]}"; ++i)); do
+    case ${args[i]} in
+        --crate-name)
+                       if [ "${args[i+1]}" = "lightning" ]; then
+                               IS_LIGHTNING=true
+                       fi
+                       ;;
+    esac
+done
+for ((i=0; i<"${#args[@]}"; ++i)); do
+    case ${args[i]} in
+        metadata*)
+                       if [ "$IS_LIGHTNING" = "true" ]; then
+                               # Pick any random value for metadata, it doesn't matter
+                               args[i]="metadata=42"
+                       fi
+                       ;;
+    esac
+done
+
+/usr/bin/rustc "${args[@]}"

diff --git a/genbindings.sh b/genbindings.sh
index 0d8a691bfdcac33aa34a314b3cbca19cf95a264b..0f74c4b302fe0181d95616e2b3c91b65891f3ee9 100755 (executable)
--- a/genbindings.sh
+++ b/genbindings.sh
@@ -50,9 +50,14 @@ else
        sed -i 's|lightning = { .*|lightning = { path = "'"$LIGHTNING_PATH"'" }|' lightning-c-bindings/Cargo.toml
 fi
 
+# Set path to include our rustc wrapper as well as cbindgen
+PATH="$(pwd)/deterministic-build-wrappers:$PATH:~/.cargo/bin"
 # Now cd to lightning-c-bindings, build the generated bindings, and call cbindgen to build a C header file
-PATH="$PATH:~/.cargo/bin"
 cd lightning-c-bindings
+# Remap paths so that our builds are deterministic
+export RUSTFLAGS="--remap-path-prefix $LIGHTNING_PATH=rust-lightning --remap-path-prefix $(pwd)=ldk-c-bindings --remap-path-prefix $HOME/.cargo= -C target-cpu=generic"
+export CFLAGS="-ffile-prefix-map=$HOME/.cargo="
+
 cargo build
 cbindgen -v --config cbindgen.toml -o include/lightning.h >/dev/null 2>&1
 
@@ -76,14 +81,14 @@ fi
 
 # Finally, sanity-check the generated C and C++ bindings with demo apps:
 
-CFLAGS="-Wall -Wno-nullability-completeness -pthread"
+LOCAL_CFLAGS="-Wall -Wno-nullability-completeness -pthread"
 
 # Naively run the C demo app:
-gcc $CFLAGS -Wall -g -pthread demo.c target/debug/libldk.a -ldl
+gcc $LOCAL_CFLAGS -Wall -g -pthread demo.c target/debug/libldk.a -ldl
 ./a.out
 
 # And run the C++ demo app in valgrind to test memory model correctness and lack of leaks.
-g++ $CFLAGS -std=c++11 -Wall -g -pthread demo.cpp -Ltarget/debug/ -lldk -ldl
+g++ $LOCAL_CFLAGS -std=c++11 -Wall -g -pthread demo.cpp -Ltarget/debug/ -lldk -ldl
 if [ -x "`which valgrind`" ]; then
        LD_LIBRARY_PATH=target/debug/ valgrind --error-exitcode=4 --memcheck:leak-check=full --show-leak-kinds=all ./a.out
        echo
@@ -93,7 +98,7 @@ fi
 
 # Test a statically-linked C++ version, tracking the resulting binary size and runtime
 # across debug, LTO, and cross-language LTO builds (using the same compiler each time).
-clang++ $CFLAGS -std=c++11 demo.cpp target/debug/libldk.a -ldl
+clang++ $LOCAL_CFLAGS -std=c++11 demo.cpp target/debug/libldk.a -ldl
 strip ./a.out
 echo " C++ Bin size and runtime w/o optimization:"
 ls -lha a.out
@@ -114,11 +119,11 @@ if [ "$HOST_PLATFORM" = "host: x86_64-unknown-linux-gnu" ]; then
                        set +e
 
                        # First the C demo app...
-                       clang-$LLVM_V $CFLAGS -fsanitize=memory -fsanitize-memory-track-origins -g demo.c target/debug/libldk.a -ldl
+                       clang-$LLVM_V $LOCAL_CFLAGS -fsanitize=memory -fsanitize-memory-track-origins -g demo.c target/debug/libldk.a -ldl
                        ./a.out
 
                        # ...then the C++ demo app
-                       clang++-$LLVM_V $CFLAGS -std=c++11 -fsanitize=memory -fsanitize-memory-track-origins -g demo.cpp target/debug/libldk.a -ldl
+                       clang++-$LLVM_V $LOCAL_CFLAGS -std=c++11 -fsanitize=memory -fsanitize-memory-track-origins -g demo.cpp target/debug/libldk.a -ldl
                        ./a.out >/dev/null
 
                        # restore exit-on-failure
@@ -184,11 +189,11 @@ if [ "$HOST_PLATFORM" = "host: x86_64-unknown-linux-gnu" -o "$HOST_PLATFORM" = "
                mv Cargo.toml.bk Cargo.toml
 
                # First the C demo app...
-               $CLANG $CFLAGS -fsanitize=address -g demo.c target/debug/libldk.a -ldl
+               $CLANG $LOCAL_CFLAGS -fsanitize=address -g demo.c target/debug/libldk.a -ldl
                ASAN_OPTIONS='detect_leaks=1 detect_invalid_pointer_pairs=1 detect_stack_use_after_return=1' ./a.out
 
                # ...then the C++ demo app
-               $CLANGPP $CFLAGS -std=c++11 -fsanitize=address -g demo.cpp target/debug/libldk.a -ldl
+               $CLANGPP $LOCAL_CFLAGS -std=c++11 -fsanitize=address -g demo.cpp target/debug/libldk.a -ldl
                ASAN_OPTIONS='detect_leaks=1 detect_invalid_pointer_pairs=1 detect_stack_use_after_return=1' ./a.out >/dev/null
        else
                echo "WARNING: Please install clang-$RUSTC_LLVM_V and clang++-$RUSTC_LLVM_V to build with address sanitizer"
@@ -197,20 +202,31 @@ else
        echo "WARNING: Can't use address sanitizer on non-Linux, non-OSX non-x86 platforms"
 fi
 
+# Now build with LTO on on both C++ and rust, but without cross-language LTO:
+# Clear stale release build artifacts from previous runs
+cargo clean --release
+CARGO_PROFILE_RELEASE_LTO=true cargo rustc -v --release -- -C lto
+clang++ $LOCAL_CFLAGS -std=c++11 -flto -O2 demo.cpp target/release/libldk.a -ldl
+
+if [ "$HOST_PLATFORM" != "host: x86_64-apple-darwin" -a "$CLANGPP" != "" ]; then
+       # If we can use cross-language LTO, use it for building C dependencies (i.e. libsecp256k1) as well
+       export CC="$CLANG"
+       export CFLAGS_wasm32_wasi="-target wasm32"
+fi
+
 if [ "$(rustc --print target-list | grep wasm32-wasi)" != "" ]; then
        # Test to see if clang supports wasm32 as a target (which is needed to build rust-secp256k1)
        echo "int main() {}" > genbindings_wasm_test_file.c
        clang -nostdlib -o /dev/null --target=wasm32-wasi -Wl,--no-entry genbindings_wasm_test_file.c > /dev/null 2>&1 &&
        # And if it does, build a WASM binary without capturing errors
        cargo rustc -v --target=wasm32-wasi -- -C embed-bitcode=yes &&
+       # Now that we've done our last non-LTO build, turn on LTO in CFLAGS as well
+       export CFLAGS="$CFLAGS -flto" &&
        CARGO_PROFILE_RELEASE_LTO=true cargo rustc -v --release --target=wasm32-wasi -- -C opt-level=s -C linker-plugin-lto -C lto ||
        echo "Cannot build WASM lib as clang does not seem to support the wasm32-wasi target"
        rm genbindings_wasm_test_file.c
 fi
 
-# Now build with LTO on on both C++ and rust, but without cross-language LTO:
-CARGO_PROFILE_RELEASE_LTO=true cargo rustc -v --release -- -C lto
-clang++ $CFLAGS -std=c++11 -flto -O2 demo.cpp target/release/libldk.a -ldl
 strip ./a.out
 echo "C++ Bin size and runtime with only RL (LTO) optimized:"
 ls -lha a.out
@@ -222,8 +238,11 @@ if [ "$HOST_PLATFORM" != "host: x86_64-apple-darwin" -a "$CLANGPP" != "" ]; then
        # or Ubuntu packages). This should work fine on Distros which do more involved
        # packaging than simply shipping the rustup binaries (eg Debian should Just Work
        # here).
+       export CFLAGS="$CFLAGS -flto"
+       # Rust doesn't recognize CFLAGS changes, so we need to clean build artifacts
+       cargo clean --release
        CARGO_PROFILE_RELEASE_LTO=true cargo rustc -v --release -- -C linker-plugin-lto -C lto -C link-arg=-fuse-ld=lld
-       $CLANGPP $CFLAGS -flto -fuse-ld=lld -O2 demo.cpp target/release/libldk.a -ldl
+       $CLANGPP $LOCAL_CFLAGS -flto -fuse-ld=lld -O2 demo.cpp target/release/libldk.a -ldl
        strip ./a.out
        echo "C++ Bin size and runtime with cross-language LTO:"
        ls -lha a.out