Custom libdir breaks std crate

[o01eg]

I maintain live-ebuild for dev channel. To avoid collision between different rust channels libdir should be set to different subdirectory: gentoo/gentoo-rust#287
It worked with configure script but was broken after moving to x.py script.

config.toml file:

[llvm]
optimize = true
release-debuginfo = false
assertions = false
[build]
build = "x86_64-unknown-linux-gnu"
host = ["x86_64-unknown-linux-gnu"]
target = ["x86_64-unknown-linux-gnu"]
docs = true
submodules = false
python = "python2.7"
locked-deps = true
vendor = false
verbose = 2
sanitizers = true
extended = true
[install]
prefix = "/usr"
libdir = "lib64/rust-9999"
docdir = "share/doc/rust-9999"
mandir = "share/rust-9999/man"
[rust]
optimize = true
debuginfo = false
debug-assertions = false
use-jemalloc = true
default-linker = "x86_64-pc-linux-gnu-gcc"
rpath = false
ignore-git = false
[target.x86_64-unknown-linux-gnu]
cc = "x86_64-pc-linux-gnu-gcc"
cxx = "x86_64-pc-linux-gnu-g++"
ar = "x86_64-pc-linux-gnu-ar"
llvm-config = "/usr/bin/x86_64-pc-linux-gnu-llvm-config"

Compiling hello world project:

$ cargo build --verbose
   Compiling tst01 v0.1.0 (file:///tmp/tst01)
     Running `rustc --crate-name tst01 src/main.rs --crate-type bin --emit=dep-info,link -C debuginfo=2 -C metadata=b838c4ea0bb50c79 -C extra-filename=-b838c4ea0bb50c79 --out-dir /tmp/tst01/target/debug/deps -L dependency=/tmp/tst01/target/debug/deps`
error[E0463]: can't find crate for `std`

error: aborting due to previous error

error: Could not compile `tst01`.

Caused by:
  process didn't exit successfully: `rustc --crate-name tst01 src/main.rs --crate-type bin --emit=dep-info,link -C debuginfo=2 -C metadata=b838c4ea0bb50c79 -C extra-filename=-b838c4ea0bb50c79 --out-dir /tmp/tst01/target/debug/deps -L dependency=/tmp/tst01/target/debug/deps` (exit code: 101)

If I set libdir to lib64 then rustc works.

rustc --version --verbose:

rustc 1.22.0-dev (db80da1c1 2017-10-17)
binary: rustc
commit-hash: db80da1c1a20529054ce6745a6219c2108693fb7
commit-date: 2017-10-17
host: x86_64-unknown-linux-gnu
release: 1.22.0-dev
LLVM version: 3.9

[o01eg]

Logs from normal compilation and failed:

https://gist.github.com/o01eg/45a337ac197dac8b03015f2536431b81#file-rust-log-failed

https://gist.github.com/o01eg/45a337ac197dac8b03015f2536431b81#file-rust-log-normal

[o01eg]

Its gone if I manually adds RUSTFLAGS="-L /usr/lib/rust-9999/ -L /usr/lib64/rust-9999/rustlib/x86_64-unknown-linux-gnu/lib/"

[o01eg]

It's looks like it was broken #44107 where script was stopped to set CFG_LIBDIR_RELATIVE

[o01eg]

I've tried to set config.libdir_relative to same value as config.libdir

rust/src/bootstrap/config.rs

Line 415 in 77ab3a1

config.libdir = install.libdir.clone().map(PathBuf::from);

It fixed this issue but gets error with building rust docs on proc_macro.

[o01eg]

It works on 1.20 but start to breaks at 1.21 and later.

[o01eg]

Breaking change for proc_macro is PR #43630 and commit facf5a9

[o01eg]

Looks like rustdoc here searches libraries in

/tmp/portage/dev-lang/rust-9999-r1/work/rust-git-src/build/x86_64-unknown-linux-gnu/stage1/lib64/rust-9999/rustlib/x86_64-unknown-linux-gnu/lib/

while stage1 libraries are in

/tmp/portage/dev-lang/rust-9999-r1/work/rust-git-src/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib/

[o01eg]

Command which failed:

rustdoc command: "/tmp/portage/dev-lang/rust-9999-r1/work/rust-git-src/build/x86_64-unknown-linux-gnu/stage2/bin/rustdoc" "--crate-name" "proc_macro" "src/libproc_macro/lib.rs" "--target" "x86_64-unknown-linux-gnu" "-o" "/tmp/portage/dev-lang/rust-9999-r1/work/rust-git-src/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/doc" "-L" "dependency=/tmp/portage/dev-lang/rust-9999-r1/work/rust-git-src/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps" "-L" "dependency=/tmp/portage/dev-lang/rust-9999-r1/work/rust-git-src/build/x86_64-unknown-linux-gnu/stage1-rustc/release/deps" "--extern" "syntax_pos=/tmp/portage/dev-lang/rust-9999-r1/work/rust-git-src/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps/libsyntax_pos-94faca1471e8dcc3.so" "--extern" "syntax=/tmp/portage/dev-lang/rust-9999-r1/work/rust-git-src/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps/libsyntax-355ef924b9232203.so" "--extern" "rustc_errors=/tmp/portage/dev-lang/rust-9999-r1/work/rust-git-src/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps/librustc_errors-24cf71b122930dcb.so" "--cfg" "stage1" "--cfg" "dox" "--sysroot" "/tmp/portage/dev-lang/rust-9999-r1/work/rust-git-src/build/x86_64-unknown-linux-gnu/stage1" "-Z" "force-unstable-if-unmarked" "-Z" "unstable-options" "--crate-version" "1.24.0-dev (0bae745cd 2017-12-03)"

Looks like either should be used custom libdir on all stages or stage2 rustdoc should use stage2 instead stage1 libraries. Maybe use stage1 rustdoc.

[nikomatsakis]

I'm not really clear on what team this is. Maybe @rust-lang/docs (rustdoc bug?) anyway, I guess there's a pending fix.

[GuillaumeGomez]

I recall a similar bug I fixed a while ago. Strange it's reappearing...