rustc: reason(s) for linker options should be introspectable/reported via command line switch

[steveklabnik]

Issue by pnkfelix
Sunday Aug 03, 2014 at 05:45 GMT

For earlier discussion, see rust-lang/rust#16210

This issue was labelled with: A-tools, I-enhancement in the Rust repository

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I tried to build gfx-rs on my mac yesterday.

I thought I had it working, but then when I tried to build the cube example that it includes, I hit a linker error:

% RUST_LOG=cargo cargo build --verbose
...
     Running `rustc main.rs --crate-name cube --crate-type bin --out-dir /Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube/target -L /Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube/target -L /Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube/target/deps -L /Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube/target/native/gl-e5df2498e985d18a -L /Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube/target/native/glfw-cd120128a43da8e1 --extern gfx=/Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube/target/deps/libgfx-b022e83c25570dad.rlib --extern cgmath=/Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube/target/deps/libcgmath-5360c9e091e9a1d6.rlib`
       Fresh cgmath v0.0.1 (https://github.com/bjz/cgmath-rs.git#0189aead)
       Fresh glfw v0.0.1 (https://github.com/bjz/glfw-rs.git#91c77bd2)
       Fresh comm v0.1.0 (file:/Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube)
       Fresh gl-init-rs v0.0.1 (https://github.com/tomaka/gl-init-rs.git#ed3ed47a)
       Fresh sax-rs v0.0.1 (https://github.com/bjz/sax-rs#fa887b57)
       Fresh gfx_macros v0.1.0 (file:/Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube)
       Fresh gl_generator v0.0.1 (https://github.com/bjz/gl-rs.git#ca705653)
       Fresh gl v0.0.1 (https://github.com/bjz/gl-rs.git#ca705653)
       Fresh device v0.1.0 (file:/Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube)
       Fresh glfw_platform v0.1.0 (file:/Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube)
       Fresh gl_init_platform v0.1.0 (file:/Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube)
       Fresh render v0.1.0 (file:/Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube)
       Fresh gfx v0.1.0 (file:/Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube)
   Compiling example-cube v0.1.0 (file:/Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube)
5:cargo::ops::cargo_rustc: executing primary
error: linking with `cc` failed: exit code: 1
note: cc '-m64' '-L' '/Users/pnkfelix/opt/rust-dbg/lib/rustlib/x86_64-apple-darwin/lib' '-o' '/Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube/target/cube' '/Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube/target/cube.o' '-Wl,-force_load,/Users/pnkfelix/opt/rust-dbg/lib/rustlib/x86_64-apple-darwin/lib/libmorestack.a' '-nodefaultlibs' '-Wl,-dead_strip' '/Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube/target/deps/libcgmath-5360c9e091e9a1d6.rlib' '/Users/pnkfelix/opt/rust-dbg/lib/rustlib/x86_64-apple-darwin/lib/libnative-4e7c5e5c.rlib' '/Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube/target/deps/libgfx-b022e83c25570dad.rlib' '/Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube/target/deps/libgl_init_platform-07f8e5a4e7852f90.rlib' '/Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube/target/deps/libglfw_platform-e57d12d968abd11c.rlib' '/Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube/target/deps/libglfw-cd120128a43da8e1.rlib' '/Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube/target/deps/librender-5a028bc6cc784f4e.rlib' '/Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube/target/deps/libdevice-d4da5ff6384e848b.rlib' '/Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube/target/deps/libgl-e5df2498e985d18a.rlib' '/Users/pnkfelix/opt/rust-dbg/lib/rustlib/x86_64-apple-darwin/lib/liblog-4e7c5e5c.rlib' '/Users/pnkfelix/opt/rust-dbg/lib/rustlib/x86_64-apple-darwin/lib/libsemver-4e7c5e5c.rlib' '/Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube/target/deps/libgl-init-rs-39edd4b8f5666e81.rlib' '/Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube/target/deps/libcomm-2045099daf6674bb.rlib' '/Users/pnkfelix/opt/rust-dbg/lib/rustlib/x86_64-apple-darwin/lib/libstd-4e7c5e5c.rlib' '/Users/pnkfelix/opt/rust-dbg/lib/rustlib/x86_64-apple-darwin/lib/libsync-4e7c5e5c.rlib' '/Users/pnkfelix/opt/rust-dbg/lib/rustlib/x86_64-apple-darwin/lib/librustrt-4e7c5e5c.rlib' '/Users/pnkfelix/opt/rust-dbg/lib/rustlib/x86_64-apple-darwin/lib/libcollections-4e7c5e5c.rlib' '/Users/pnkfelix/opt/rust-dbg/lib/rustlib/x86_64-apple-darwin/lib/liballoc-4e7c5e5c.rlib' '/Users/pnkfelix/opt/rust-dbg/lib/rustlib/x86_64-apple-darwin/lib/liblibc-4e7c5e5c.rlib' '/Users/pnkfelix/opt/rust-dbg/lib/rustlib/x86_64-apple-darwin/lib/libunicode-4e7c5e5c.rlib' '/Users/pnkfelix/opt/rust-dbg/lib/rustlib/x86_64-apple-darwin/lib/librand-4e7c5e5c.rlib' '/Users/pnkfelix/opt/rust-dbg/lib/rustlib/x86_64-apple-darwin/lib/libcore-4e7c5e5c.rlib' '-L' '/Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube/target/native/gl-e5df2498e985d18a' '-L' '/Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube/target/deps' '-L' '/Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube/target/native/glfw-cd120128a43da8e1' '-L' '/Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube/target' '-L' '/Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube/.rust' '-L' '/Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube' '-lglfw3' '-framework' 'Cocoa' '-framework' 'OpenGL' '-framework' 'IOKit' '-framework' 'CoreFoundation' '-framework' 'CoreVideo' '-lGL' '-lX11' '-lSystem' '-lpthread' '-lc' '-lm' '-lcompiler-rt'
note: ld: warning: directory not found for option '-L/Users/pnkfelix/Dev/Rust/gfx-rs/src/examples/cube/.rust'
ld: library not found for -lGL
clang: error: linker command failed with exit code 1 (use -v to see invocation)

So, here is the issue: I see we have -framework OpenGL in the invocation. But there is also -lGL and -lX11 in the above command. And I have no idea which crate (gfx-rs has many subcrates it pulls in via cargo) is injecting which of those linker directives.

This bug is for fixing the implicit tooling issue here (not about fixing gfx-rs itself to work on OS X). From what I can see from skimming cargo's source code, the linker directives are not being inserted by cargo, but rather by rustc; but there is no way for me to modify the rustc command line that cargo gives me to find out more information about which crate(s) is the source for each linker flag.