Open
Description
openedon Apr 17, 2019
$ cargo new testcase
$ cd testcase
$ RUSTFLAGS="-Clinker-plugin-lto" cargo run --release
Yields the following on mac:
Compiling testcase v0.1.0 (/Users/glandium/testcase)
error: linking with `cc` failed: exit code: 1
|
= note: "cc" "-m64" "-Wl,-plugin-opt=O3" "-Wl,-plugin-opt=mcpu=core2" "-L" "/Users/glandium/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/x86_64-apple-darwin/lib" "/Users/glandium/testcase/target/release/deps/testcase-d97266bc083c0e9e.testcase.4ank1dht-cgu.0.rcgu.o" "/Users/glandium/testcase/target/release/deps/testcase-d97266bc083c0e9e.testcase.4ank1dht-cgu.1.rcgu.o" "-o" "/Users/glandium/testcase/target/release/deps/testcase-d97266bc083c0e9e" "/Users/glandium/testcase/target/release/deps/testcase-d97266bc083c0e9e.3pvtkuuqiy7p6wge.rcgu.o" "-Wl,-dead_strip" "-nodefaultlibs" "-L" "/Users/glandium/testcase/target/release/deps" "-L" "/Users/glandium/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/x86_64-apple-darwin/lib" "/Users/glandium/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/x86_64-apple-darwin/lib/libstd-64d1544b9dc8a8d7.rlib" "/Users/glandium/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/x86_64-apple-darwin/lib/libpanic_unwind-47702365139f147e.rlib" "/Users/glandium/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/x86_64-apple-darwin/lib/libbacktrace_sys-0aefa3a2bfa44649.rlib" "/Users/glandium/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/x86_64-apple-darwin/lib/libunwind-c2b22c88cacffeb6.rlib" "/Users/glandium/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/x86_64-apple-darwin/lib/librustc_demangle-fca4484aa9be2d09.rlib" "/Users/glandium/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/x86_64-apple-darwin/lib/liblibc-4728c64ee20d89f8.rlib" "/Users/glandium/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/x86_64-apple-darwin/lib/liballoc-1722fbf72ce989c9.rlib" "/Users/glandium/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/x86_64-apple-darwin/lib/librustc_std_workspace_core-0836ff3f3d6a6ee6.rlib" "/Users/glandium/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/x86_64-apple-darwin/lib/libcore-91c9fbc323ad09b7.rlib" "/Users/glandium/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/x86_64-apple-darwin/lib/libcompiler_builtins-43b96ba2cdcc7cb3.rlib" "-lSystem" "-lresolv" "-lc" "-lm"
= note: ld: unknown option: -plugin-opt=O3
clang: error: linker command failed with exit code 1 (use -v to see invocation)
error: aborting due to previous error
error: Could not compile `testcase`.
To learn more, run the command again with --verbose.
On mac, the default linker is ld64. rustc really invokes cc, which invokes ld64 with the flags passed with -Wl and some others depending on the other command line arguments. ld64 does support the LLVM plugin... but doesn't support the -plugin-opt option to pass arguments to it. I know some things can be passed with -Wl,-mllvm,... but I don't know if that includes things that rust is trying to pass here.
On Linux, it's funnier:
Compiling testcase v0.1.0 (/tmp/testcase)
error: linking with `cc` failed: exit code: 1
|
= note: "cc" "-Wl,--as-needed" "-Wl,-z,noexecstack" "-m64" "-Wl,-plugin-opt=O3" "-Wl,-plugin-opt=mcpu=x86-64" "-L" "/home/glandium/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib" "/tmp/testcase/target/release/deps/testcase-576934ab8201a4ea.testcase.dl00diw9-cgu.0.rcgu.o" "/tmp/testcase/target/release/deps/testcase-576934ab8201a4ea.testcase.dl00diw9-cgu.1.rcgu.o" "-o" "/tmp/testcase/target/release/deps/testcase-576934ab8201a4ea" "/tmp/testcase/target/release/deps/testcase-576934ab8201a4ea.y29oqvxl224jt9k.rcgu.o" "-Wl,--gc-sections" "-pie" "-Wl,-zrelro" "-Wl,-znow" "-Wl,-O1" "-nodefaultlibs" "-L" "/tmp/testcase/target/release/deps" "-L" "/home/glandium/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib" "-Wl,--start-group" "-Wl,-Bstatic" "/home/glandium/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libstd-bbd8cb236ab3b537.rlib" "/home/glandium/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libpanic_unwind-334e405e4bdf1791.rlib" "/home/glandium/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libbacktrace_sys-1e14a089a9f63178.rlib" "/home/glandium/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libunwind-f1aae4818bd13556.rlib" "/home/glandium/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/librustc_demangle-a32c94e7da1105b4.rlib" "/home/glandium/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/liblibc-e214e2acd110aec9.rlib" "/home/glandium/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/liballoc-fbf429991e30afee.rlib" "/home/glandium/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/librustc_std_workspace_core-1734308ff05fb551.rlib" "/home/glandium/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libcore-b349c8b817f959a5.rlib" "-Wl,--end-group" "/home/glandium/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libcompiler_builtins-c4b4b16c70e666d9.rlib" "-Wl,-Bdynamic" "-ldl" "-lrt" "-lpthread" "-lgcc_s" "-lc" "-lm" "-lrt" "-lpthread" "-lutil" "-lutil"
= note: /tmp/testcase/target/release/deps/testcase-576934ab8201a4ea.testcase.dl00diw9-cgu.0.rcgu.o: file not recognized: file format not recognized
collect2: error: ld returned 1 exit status
error: aborting due to previous error
error: Could not compile `testcase`.
To learn more, run the command again with --verbose.
Because cc is gcc, this just plain doesn't work, for no obvious reason. At the very least, it seems rust should try to use clang instead of cc in that case.
But that also fails:
RUSTFLAGS="-Clinker=clang-8 -Clinker-plugin-lto" cargo run --release
Compiling testcase v0.1.0 (/tmp/testcase)
error: linking with `clang-8` failed: exit code: 1
|
= note: "clang-8" "-Wl,--as-needed" "-Wl,-z,noexecstack" "-m64" "-Wl,-plugin-opt=O3" "-Wl,-plugin-opt=mcpu=x86-64" "-L" "/home/glandium/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib" "/tmp/testcase/target/release/deps/testcase-e3dc53d119c25549.testcase.ci8upasg-cgu.0.rcgu.o" "/tmp/testcase/target/release/deps/testcase-e3dc53d119c25549.testcase.ci8upasg-cgu.1.rcgu.o" "-o" "/tmp/testcase/target/release/deps/testcase-e3dc53d119c25549" "/tmp/testcase/target/release/deps/testcase-e3dc53d119c25549.61wo3nlknhbro8d.rcgu.o" "-Wl,--gc-sections" "-pie" "-Wl,-zrelro" "-Wl,-znow" "-Wl,-O1" "-nodefaultlibs" "-L" "/tmp/testcase/target/release/deps" "-L" "/home/glandium/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib" "-Wl,--start-group" "-Wl,-Bstatic" "/home/glandium/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libstd-bbd8cb236ab3b537.rlib" "/home/glandium/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libpanic_unwind-334e405e4bdf1791.rlib" "/home/glandium/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libbacktrace_sys-1e14a089a9f63178.rlib" "/home/glandium/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libunwind-f1aae4818bd13556.rlib" "/home/glandium/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/librustc_demangle-a32c94e7da1105b4.rlib" "/home/glandium/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/liblibc-e214e2acd110aec9.rlib" "/home/glandium/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/liballoc-fbf429991e30afee.rlib" "/home/glandium/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/librustc_std_workspace_core-1734308ff05fb551.rlib" "/home/glandium/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libcore-b349c8b817f959a5.rlib" "-Wl,--end-group" "/home/glandium/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libcompiler_builtins-c4b4b16c70e666d9.rlib" "-Wl,-Bdynamic" "-ldl" "-lrt" "-lpthread" "-lgcc_s" "-lc" "-lm" "-lrt" "-lpthread" "-lutil" "-lutil"
= note: /usr/bin/ld: bad -plugin-opt option
clang: error: linker command failed with exit code 1 (use -v to see invocation)
error: aborting due to previous error
error: Could not compile `testcase`.
To learn more, run the command again with --verbose.
And here, the reason is essentially the same: the underlying linker doesn't support the -plugin-opt flag... except it does, but not when it's not passed -plugin, which happens when the compiler passes it, which happens when -flto was on its command line:
$ RUSTFLAGS="-Clinker=clang-8 -Clinker-plugin-lto -Clink-arg=-flto" cargo run --release Compiling testcase v0.1.0 (/tmp/testcase)
Finished release [optimized] target(s) in 0.28s
Running `target/release/testcase`
Hello, world!
Using lld works too, because it doesn't need an explicit -plugin:
$ RUSTFLAGS="-Clinker=clang-8 -Clinker-plugin-lto -Clink-arg=-fuse-ld=lld" cargo run --release
Compiling testcase v0.1.0 (/tmp/testcase)
Finished release [optimized] target(s) in 0.36s
Running `target/release/testcase`
Hello, world!
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment