Merge #574: Overcome ASAN false positive regression

5a3f13e Overcome ASAN false positive regression (Tobin C. Harding)

Pull request description:

  The Memory Sanitizer is giving a false positive at the moment in `nightly`. Adding compiler flags resolves the issue. I didn't grok the exact root cause but this fixes it (cut'n'pasta from the issue [0]).

  Props to elichai for working this out: #573 (comment)

  [0] rust-lang/rust#107149

ACKs for top commit:
  apoelstra:
    ACK 5a3f13e

Tree-SHA512: 873145b732f7574c93ecc1bbabd9d82a1e501a39d1e2184770f71a07ffb72468783ab1b3fbfef8ef377c7e7a4b8c45253da1fce11660152d3369902136f1c049

Author: apoelstra

contrib/test.sh

@@ -81,8 +81,10 @@ if [ "$DO_ASAN" = true ]; then
     ASAN_OPTIONS='detect_leaks=1 detect_invalid_pointer_pairs=1 detect_stack_use_after_return=1' \
     cargo test --lib --all --features="$FEATURES" -Zbuild-std --target x86_64-unknown-linux-gnu
     cargo clean
-    CC='clang -fsanitize=memory -fno-omit-frame-pointer'                                         \
-    RUSTFLAGS='-Zsanitizer=memory -Zsanitizer-memory-track-origins -Cforce-frame-pointers=yes'   \
+    # The -Cllvm-args=-msan-eager-checks=0 flag was added to overcome this issue:
+    # https://github.com/rust-bitcoin/rust-secp256k1/pull/573#issuecomment-1399465995
+    CC='clang -fsanitize=memory -fno-omit-frame-pointer'                                                                        \
+    RUSTFLAGS='-Zsanitizer=memory -Zsanitizer-memory-track-origins -Cforce-frame-pointers=yes -Cllvm-args=-msan-eager-checks=0' \
     cargo test --lib --all --features="$FEATURES" -Zbuild-std --target x86_64-unknown-linux-gnu
     cargo run --release --manifest-path=./no_std_test/Cargo.toml | grep -q "Verified Successfully"
     cargo run --release --features=alloc --manifest-path=./no_std_test/Cargo.toml | grep -q "Verified alloc Successfully"