On master, rustc 1.61.0 fails to link fibonacci example with --sanitizer NONE

[Ekleog]

Hi!

Following #71, I switched to using cargo-bolero from commit 7187c3f.

Then, trying to build the fibonacci example with stable rustc (so 1.61.0 as of this writing), I'm now getting the following linker error:

   Compiling test-bolero v0.1.0 (/home/ekleog/prog/test-bolero)
error: linking with `cc` failed: exit status: 1
  |
  = note: "cc" "-m64" "/home/ekleog/prog/test-bolero/target/fuzz/build_71e6fd6154e07acb/x86_64-unknown-linux-gnu/release/deps/test_bolero-03796c9c1fd7ff1a.test_bolero.a997a281-cgu.0.rcgu.o" "/home/ekleog/prog/test-bolero/target/fuzz/build_71e6fd6154e07acb/x86_64-unknown-linux-gnu/release/deps/test_bolero-03796c9c1fd7ff1a.rufpas6580vdgtv.rcgu.o" "-Wl,--as-needed" "-L" "/home/ekleog/prog/test-bolero/target/fuzz/build_71e6fd6154e07acb/x86_64-unknown-linux-gnu/release/deps" "-L" "/home/ekleog/prog/test-bolero/target/fuzz/build_71e6fd6154e07acb/release/deps" "-L" "/home/ekleog/prog/test-bolero/target/fuzz/build_71e6fd6154e07acb/x86_64-unknown-linux-gnu/release/build/bolero-libfuzzer-41b6a54ed54d4993/out" "-L" "/home/ekleog/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib" "-Wl,-Bstatic" "/home/ekleog/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libtest-efede371ca078f25.rlib" "/home/ekleog/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libgetopts-84fb18ba7592ffd9.rlib" "/home/ekleog/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libunicode_width-a1dc360b97cf3afc.rlib" "/home/ekleog/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/librustc_std_workspace_std-4220d815fd1849e6.rlib" "-Wl,--start-group" "/home/ekleog/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libstd-05b39ac0cb4c5688.rlib" "/home/ekleog/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libpanic_unwind-ccaa149b737d6503.rlib" "/home/ekleog/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libobject-a94a6388c153126b.rlib" "/home/ekleog/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libmemchr-1ecfa264246b85c6.rlib" "/home/ekleog/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libaddr2line-ee710154a50440b8.rlib" "/home/ekleog/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libgimli-f09986d873ea8592.rlib" "/home/ekleog/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/librustc_demangle-f3521e20c99619ab.rlib" "/home/ekleog/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libstd_detect-df6036c77d75ce21.rlib" "/home/ekleog/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libhashbrown-24f91c1a1dfc7e13.rlib" "/home/ekleog/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libminiz_oxide-bffcc61991adb202.rlib" "/home/ekleog/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libadler-cf22313353d8663e.rlib" "/home/ekleog/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/librustc_std_workspace_alloc-c45fb100f99430e9.rlib" "/home/ekleog/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libunwind-0cdc47a8a81950ea.rlib" "/home/ekleog/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libcfg_if-f1e158606c4c82f6.rlib" "/home/ekleog/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/liblibc-0b608b5ef4df0ec4.rlib" "/home/ekleog/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/liballoc-b8438dc0bcbbcc08.rlib" "/home/ekleog/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/librustc_std_workspace_core-70e2ae036775ff2f.rlib" "/home/ekleog/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libcore-815d281f7068a893.rlib" "-Wl,--end-group" "/home/ekleog/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libcompiler_builtins-377835cfab8dae0d.rlib" "-Wl,-Bdynamic" "-lgcc_s" "-lutil" "-lrt" "-lpthread" "-lm" "-ldl" "-lc" "-Wl,--eh-frame-hdr" "-Wl,-znoexecstack" "-L" "/home/ekleog/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib" "-o" "/home/ekleog/prog/test-bolero/target/fuzz/build_71e6fd6154e07acb/x86_64-unknown-linux-gnu/release/deps/test_bolero-03796c9c1fd7ff1a" "-pie" "-Wl,-zrelro,-znow" "-Wl,-O1" "-nodefaultlibs" "-fuse-ld=gold"
  = note: /rustc/fe5b13d681f25ee6474be29d748c65adcd91f69e/library/std/src/sys_common/backtrace.rs:118: error: undefined reference to '__sancov_lowest_stack'
          /rustc/fe5b13d681f25ee6474be29d748c65adcd91f69e/library/core/src/ops/function.rs:227: error: undefined reference to '__sanitizer_cov_trace_pc_indir'
          /rustc/fe5b13d681f25ee6474be29d748c65adcd91f69e/library/std/src/rt.rs:139: error: undefined reference to '__sancov_lowest_stack'
          /rustc/fe5b13d681f25ee6474be29d748c65adcd91f69e/library/std/src/rt.rs:145: error: undefined reference to '__sancov_lowest_stack'
          /rustc/fe5b13d681f25ee6474be29d748c65adcd91f69e/library/core/src/fmt/mod.rs:2132: error: undefined reference to '__sancov_lowest_stack'
          /rustc/fe5b13d681f25ee6474be29d748c65adcd91f69e/library/core/src/cmp.rs:1396: error: undefined reference to '__sanitizer_cov_trace_cmp8'
          /rustc/fe5b13d681f25ee6474be29d748c65adcd91f69e/library/core/src/fmt/mod.rs:388: error: undefined reference to '__sanitizer_cov_trace_cmp8'
          /rustc/fe5b13d681f25ee6474be29d748c65adcd91f69e/library/core/src/fmt/mod.rs:388: error: undefined reference to '__sanitizer_cov_trace_cmp8'
          /rustc/fe5b13d681f25ee6474be29d748c65adcd91f69e/library/core/src/ops/function.rs:227: error: undefined reference to '__sanitizer_cov_trace_pc_indir'
          /rustc/fe5b13d681f25ee6474be29d748c65adcd91f69e/library/core/src/cmp.rs:1396: error: undefined reference to '__sanitizer_cov_trace_cmp8'
          /rustc/fe5b13d681f25ee6474be29d748c65adcd91f69e/library/core/src/cmp.rs:1396: error: undefined reference to '__sanitizer_cov_trace_const_cmp8'
          /home/ekleog/prog/test-bolero/target/fuzz/build_71e6fd6154e07acb/x86_64-unknown-linux-gnu/release/deps/test_bolero-03796c9c1fd7ff1a.test_bolero.a997a281-cgu.0.rcgu.o:test_bolero.a997a281-cgu.0:function sancov.module_ctor_8bit_counters: error: undefined reference to '__sanitizer_cov_8bit_counters_init'
          /home/ekleog/prog/test-bolero/target/fuzz/build_71e6fd6154e07acb/x86_64-unknown-linux-gnu/release/deps/test_bolero-03796c9c1fd7ff1a.test_bolero.a997a281-cgu.0.rcgu.o:test_bolero.a997a281-cgu.0:function sancov.module_ctor_8bit_counters: error: undefined reference to '__sanitizer_cov_pcs_init'
          collect2: error: ld returned 1 exit status

  = help: some `extern` functions couldn't be found; some native libraries may need to be installed or have their path specified
  = note: use the `-l` flag to specify native libraries to link
  = note: use the `cargo:rustc-link-lib` directive to specify the native libraries to link with Cargo (see https://doc.rust-lang.org/cargo/reference/build-scripts.html#cargorustc-link-libkindname)

error: could not compile `test-bolero` due to previous error
error: process exited with status 101

It seems to me like libfuzzer is missing some stuff from sancov it's expecting to have when being built with --sanitizer NONE.

When trying with --engine afl, it's only missing __sanitizer_cov_trace_pc_guard, and trying with --engine honggfuzz I'm getting invalid fuzzer "honggfuzz".

Maybe sancov still needs to be enabled even when sanitizers are disabled in order for fuzzers to know the pc trace? But then I'm not sure whether it can actually be enabled on stable :/

[camshaft]

trying with --engine honggfuzz I'm getting invalid fuzzer "honggfuzz".

I disabled honggfuzz by default when installing cargo-bolero since it required a few system dependencies that not everyone has. You can reenable it with --features honggfuzz

Maybe sancov still needs to be enabled even when sanitizers are disabled in order for fuzzers to know the pc trace? But then I'm not sure whether it can actually be enabled on stable :/

It used to be that those symbols are weakly linked by the engine but it may have changed in the latest release.

[Ekleog]

Thank you for your answer! I guess the reason why the symbols are not actually weakly linked is because, in order to run on rustc stable, I'm using --sanitizer NONE? I'm more surprised by the fact that sancov could be used on stable rust at some point than by the fact that it no longer appears to work TBH

As for honggfuzz, I've been able to use it, but it's making gold crash so I added the info about that to #26 :)

I guess I'll probably try to remove the "works on stable" requirement, as cargo-bolero still seems much more usable than cargo-fuzz to me! :)