Speed up rustdoc run a bit

[GuillaumeGomez]

r? @QuietMisdreavus

[rust-highfive]

The job x86_64-gnu-llvm-6.0 of your PR failed on Travis (raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.

travis_time:end:00207538:start=1553643969636459964,finish=1553644062502086956,duration=92865626992
$ git checkout -qf FETCH_HEAD
travis_fold:end:git.checkout

Encrypted environment variables have been removed for security reasons.
See https://docs.travis-ci.com/user/pull-requests/#pull-requests-and-security-restrictions
$ export SCCACHE_BUCKET=rust-lang-ci-sccache2
$ export SCCACHE_REGION=us-west-1
$ export GCP_CACHE_BUCKET=rust-lang-ci-cache
Setting environment variables from .travis.yml
---
#####################################################################     96.2%
######################################################################## 100.0%
[00:01:39] extracting /checkout/obj/build/cache/2019-03-20/cargo-beta-x86_64-unknown-linux-gnu.tar.gz
[00:01:39]     Updating crates.io index
[00:01:54] error: the lock file /checkout/Cargo.lock needs to be updated but --locked was passed to prevent this
[00:01:54] Build completed unsuccessfully in 0:00:40
[00:01:54] Makefile:69: recipe for target 'prepare' failed
[00:01:54] make: *** [prepare] Error 1
[00:01:55] Command failed. Attempt 2/5:
[00:01:55] Command failed. Attempt 2/5:
[00:01:55]     Updating crates.io index
[00:01:56] error: the lock file /checkout/Cargo.lock needs to be updated but --locked was passed to prevent this
[00:01:56] Build completed unsuccessfully in 0:00:00
[00:01:56] make: *** [prepare] Error 1
[00:01:56] Makefile:69: recipe for target 'prepare' failed
[00:01:58] Command failed. Attempt 3/5:
[00:01:58] Command failed. Attempt 3/5:
[00:01:58]     Updating crates.io index
[00:01:58] error: the lock file /checkout/Cargo.lock needs to be updated but --locked was passed to prevent this
[00:01:58] Build completed unsuccessfully in 0:00:00
[00:01:58] Makefile:69: recipe for target 'prepare' failed
[00:01:58] make: *** [prepare] Error 1
[00:02:01] Command failed. Attempt 4/5:
[00:02:01] Command failed. Attempt 4/5:
[00:02:02]     Updating crates.io index
[00:02:02] error: the lock file /checkout/Cargo.lock needs to be updated but --locked was passed to prevent this
[00:02:02] Build completed unsuccessfully in 0:00:00
[00:02:02] Makefile:69: recipe for target 'prepare' failed
[00:02:02] make: *** [prepare] Error 1
[00:02:06] Command failed. Attempt 5/5:
[00:02:06] Command failed. Attempt 5/5:
[00:02:06]     Updating crates.io index
[00:02:07] error: the lock file /checkout/Cargo.lock needs to be updated but --locked was passed to prevent this
[00:02:07] Build completed unsuccessfully in 0:00:00
[00:02:07] Makefile:69: recipe for target 'prepare' failed
[00:02:07] make: *** [prepare] Error 1
[00:02:07] The command has failed after 5 attempts.
---
travis_time:end:1644d217:start=1553644201017268099,finish=1553644201024008180,duration=6740081
travis_fold:end:after_failure.3
travis_fold:start:after_failure.4
travis_time:start:24ac9d00
$ ln -s . checkout && for CORE in obj/cores/core.*; do EXE=$(echo $CORE | sed 's|obj/cores/core\.[0-9]*\.!checkout!\(.*\)|\1|;y|!|/|'); if [ -f "$EXE" ]; then printf travis_fold":start:crashlog\n\033[31;1m%s\033[0m\n" "$CORE"; gdb --batch -q -c "$CORE" "$EXE" -iex 'set auto-load off' -iex 'dir src/' -iex 'set sysroot .' -ex bt -ex q; echo travis_fold":"end:crashlog; fi; done || true
travis_fold:end:after_failure.4
travis_fold:start:after_failure.5
travis_time:start:01cbc54a
travis_time:start:01cbc54a
$ cat ./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/clang_rt.asan-dynamic-i386.vers || true
cat: ./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/clang_rt.asan-dynamic-i386.vers: No such file or directory
travis_fold:end:after_failure.5
travis_fold:start:after_failure.6
travis_time:start:02b40a96
$ dmesg | grep -i kill

I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact @TimNN. (Feature Requests)

[QuietMisdreavus]

[00:01:39]     Updating crates.io index
[00:01:54] error: the lock file /checkout/Cargo.lock needs to be updated but --locked was passed to prevent this
[00:01:54] failed to run: /checkout/obj/build/x86_64-unknown-linux-gnu/stage0/bin/cargo build --manifest-path /checkout/src/bootstrap/Cargo.toml --locked
[00:01:54] Build completed unsuccessfully in 0:00:40
[00:01:54] Makefile:69: recipe for target 'prepare' failed
[00:01:54] make: *** [prepare] Error 1
[00:01:55] Command failed.

Looks like you forgot to push the lock file changes?

[GuillaumeGomez]

This is very likely...

[Centril]

Ping from triage, @QuietMisdreavus :)

[QuietMisdreavus]

@bors r+

[bors]

📌 Commit 7f2c726 has been approved by QuietMisdreavus