Cannot build fuzz targets in release mode: __sancov_guards has both ordered and unordered sections

[ebarnard]

Running cargo fuzz run -O TARGET results in

/usr/bin/ld: __sancov_guards has both ordered [`__sancov_guards' in /home/me/rust-plist/fuzz/target/x86_64-unknown-linux-gnu/release/deps/binary_reader-f85fd5bec5488622.binary_reader.7pvxwz2b-cgu.1.rcgu.o] and unordered [`__sancov_guards' in /home/me/rust-plist/fuzz/target/x86_64-unknown-linux-gnu/release/deps/binary_reader-f85fd5bec5488622.binary_reader.7pvxwz2b-cgu.10.rcgu.o] sections

/usr/bin/ld: final link failed: Bad value

This can be worked around by forcing a single codegen unit i.e.

RUSTFLAGS='-C codegen-units=1' cargo +nightly fuzz run -O TARGET

so it is presumably related to thinlto.

Running:
Ubuntu 16.04 x86_64
rustc 1.31.0-nightly (b2d6ea98b 2018-10-07)
cargo-fuzz 0.5.2

[frewsxcv]

rust-lang/rust#53945

[barrbrain]

Is this issue resolved by #215?

[ebarnard]

I haven't had any issues with cargo-fuzz recently so I presume so.