Compilation fails if using lld

[TheRawMeatball]

In my ~/.cargo/config.toml, I have the following entry:

[target.x86_64-unknown-linux-gnu]
linker = "clang"
rustflags = ["-Clink-arg=-fuse-ld=lld"]

to improve link times and iteration speed. However, this seems to break linkme compilation, badly.

Here's a snippet from the error message during compilation:

  = note: ld.lld: error: undefined symbol: __start_linkme_BENCHMARKS                                                                                                                                                                                                                                                  
          >>> referenced by 29qlfu0bgl5pi1ii                                                                                                                                                                                                                                                                          
          >>>               /home/meatball/coding/linkme/target/debug/deps/example-d6ac051010cd24ec.29qlfu0bgl5pi1ii.rcgu.o:(example::BENCHMARKS::h84fb1b0801cd0cb3)                                                                                                                                                  
          >>> the encapsulation symbol needs to be retained under --gc-sections properly; consider -z nostart-stop-gc (see https://lld.llvm.org/ELF/start-stop-gc)                                                                                                                                                    
                                                                                                                                                                                                                                                                                                                      
          ld.lld: error: undefined symbol: __stop_linkme_BENCHMARKS                                                                                                                                                                                                                                                   
          >>> referenced by 29qlfu0bgl5pi1ii                                                                                                                                                                                                                                                                          
          >>>               /home/meatball/coding/linkme/target/debug/deps/example-d6ac051010cd24ec.29qlfu0bgl5pi1ii.rcgu.o:(example::BENCHMARKS::h84fb1b0801cd0cb3)                                                                                                                                                  
                                                                                                                                                                                                                                                                                                                      
          ld.lld: error: undefined symbol: __start_linkm2_BENCHMARKS                                                                                                                                                                                                                                                  
          >>> referenced by 29qlfu0bgl5pi1ii                                                                                                                                                                                                                                                                          
          >>>               /home/meatball/coding/linkme/target/debug/deps/example-d6ac051010cd24ec.29qlfu0bgl5pi1ii.rcgu.o:(example::BENCHMARKS::h84fb1b0801cd0cb3)                                                                                                                                                  
          >>> the encapsulation symbol needs to be retained under --gc-sections properly; consider -z nostart-stop-gc (see https://lld.llvm.org/ELF/start-stop-gc)                                                                                                                                                    
                                                                                                                                                                                                                                                                                                                      
          ld.lld: error: undefined symbol: __stop_linkm2_BENCHMARKS                                                                                                                                                                                                                                                   
          >>> referenced by 29qlfu0bgl5pi1ii                                                                                                                                                                                                                                                                          
          >>>               /home/meatball/coding/linkme/target/debug/deps/example-d6ac051010cd24ec.29qlfu0bgl5pi1ii.rcgu.o:(example::BENCHMARKS::h84fb1b0801cd0cb3)                                                                                                                                                  
          clang-14: error: linker command failed with exit code 1 (use -v to see invocation)                                                                                                                                                                                                                          

[TheRawMeatball]

Update: updating the config.toml entry to use the following seems to make all the tests compile and pass.

[target.x86_64-unknown-linux-gnu]
linker = "clang"
rustflags = ["-Clink-arg=-fuse-ld=lld", "-Clink-arg=-z", "-Clink-arg=nostart-stop-gc"]

Leaving the issue open as a request for this to be documented

[TheRawMeatball]

Apparently this is a duplicate of #49.

[dtolnay]

I changed the title of #49 to remove the impression it's specific to FreeBSD.