travis: Don't set `RUST_LOG` globally

I have a suspicion that this caused a large regression in cycle times by forcing
the compiler to perform more checks on every `debug!` statement, so let's test
this out by removing the `RUST_LOG` env var globally.

This regression in cycle time was witnessed between [two] [builds] where the
[PR] in question didn't do much suspicious. Judging by how the stage0 times
*also* regressed though then this is my best guess.

[two]: https://travis-ci.org/rust-lang/rust/builds/210149932
[builds]: https://travis-ci.org/rust-lang/rust/builds/210179995
[PR]: https://github.com/rust-lang/rust/pull/40446

5 files changed, 12 insertions, 14 deletions

diff --git a/.travis.yml b/.travis.yml
index fb9e2136f1b..b4f558099da 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -47,7 +47,6 @@ matrix:
         SRC=.
         RUSTC_RETRY_LINKER_ON_SEGFAULT=1
         SCCACHE_ERROR_LOG=/tmp/sccache.log
-        RUST_LOG=sccache=debug
         MACOSX_DEPLOYMENT_TARGET=10.8
         MACOSX_STD_DEPLOYMENT_TARGET=10.7
       os: osx
@@ -61,7 +60,6 @@ matrix:
         SRC=.
         RUSTC_RETRY_LINKER_ON_SEGFAULT=1
         SCCACHE_ERROR_LOG=/tmp/sccache.log
-        RUST_LOG=sccache=debug
         MACOSX_DEPLOYMENT_TARGET=10.8
         MACOSX_STD_DEPLOYMENT_TARGET=10.7
       os: osx
@@ -75,7 +73,6 @@ matrix:
         DEPLOY=1
         RUSTC_RETRY_LINKER_ON_SEGFAULT=1
         SCCACHE_ERROR_LOG=/tmp/sccache.log
-        RUST_LOG=sccache=debug
         MACOSX_DEPLOYMENT_TARGET=10.8
         MACOSX_STD_DEPLOYMENT_TARGET=10.7
       os: osx
@@ -90,7 +87,6 @@ matrix:
         DEPLOY=1
         RUSTC_RETRY_LINKER_ON_SEGFAULT=1
         SCCACHE_ERROR_LOG=/tmp/sccache.log
-        RUST_LOG=sccache=debug
         MACOSX_DEPLOYMENT_TARGET=10.8
         MACOSX_STD_DEPLOYMENT_TARGET=10.7
       os: osx
@@ -109,7 +105,6 @@ matrix:
         DEPLOY_ALT=1
         RUSTC_RETRY_LINKER_ON_SEGFAULT=1
         SCCACHE_ERROR_LOG=/tmp/sccache.log
-        RUST_LOG=sccache=debug
         MACOSX_DEPLOYMENT_TARGET=10.8
         MACOSX_STD_DEPLOYMENT_TARGET=10.7
       os: osx
diff --git a/appveyor.yml b/appveyor.yml
index 8de49cc834d..499f7d602e3 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -131,7 +131,6 @@ install:
   - handle.exe -accepteula -help
 
   # Attempt to debug sccache failures
-  - set RUST_LOG=sccache=debug
   - set SCCACHE_ERROR_LOG=%CD%/sccache.log
 
 test_script:
diff --git a/src/Cargo.lock b/src/Cargo.lock
index a9a6fabb5b2..9ae894061a6 100644
--- a/src/Cargo.lock
+++ b/src/Cargo.lock
@@ -73,7 +73,7 @@ name = "bootstrap"
 version = "0.0.0"
 dependencies = [
  "build_helper 0.1.0",
- "cmake 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cmake 0.1.22 (registry+https://github.com/rust-lang/crates.io-index)",
  "filetime 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "gcc 0.3.44 (registry+https://github.com/rust-lang/crates.io-index)",
  "getopts 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -119,7 +119,7 @@ dependencies = [
 
 [[package]]
 name = "cmake"
-version = "0.1.21"
+version = "0.1.22"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "gcc 0.3.44 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -471,7 +471,7 @@ version = "0.0.0"
 dependencies = [
  "alloc_system 0.0.0",
  "build_helper 0.1.0",
- "cmake 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cmake 0.1.22 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
 ]
 
@@ -614,7 +614,7 @@ version = "0.0.0"
 dependencies = [
  "alloc_system 0.0.0",
  "build_helper 0.1.0",
- "cmake 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cmake 0.1.22 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
 ]
 
@@ -658,7 +658,7 @@ version = "0.0.0"
 dependencies = [
  "alloc_system 0.0.0",
  "build_helper 0.1.0",
- "cmake 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cmake 0.1.22 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
 ]
 
@@ -752,7 +752,7 @@ version = "0.0.0"
 dependencies = [
  "alloc_system 0.0.0",
  "build_helper 0.1.0",
- "cmake 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cmake 0.1.22 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
 ]
 
@@ -994,7 +994,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum bitflags 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "4f67931368edf3a9a51d29886d245f1c3db2f1ef0dcc9e35ff70341b78c10d23"
 "checksum bitflags 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)" = "826e1ab483fc81a8143faa7203c4a3c02888ebd1a782e37e41fa34753ba9a162"
 "checksum clap 2.21.1 (registry+https://github.com/rust-lang/crates.io-index)" = "74a80f603221c9cd9aa27a28f52af452850051598537bb6b359c38a7d61e5cda"
-"checksum cmake 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)" = "e1acc68a3f714627af38f9f5d09706a28584ba60dfe2cca68f40bf779f941b25"
+"checksum cmake 0.1.22 (registry+https://github.com/rust-lang/crates.io-index)" = "d18d68987ed4c516dcc3e7913659bfa4076f5182eea4a7e0038bb060953e76ac"
 "checksum dtoa 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)" = "80c8b71fd71146990a9742fc06dcbbde19161a267e0ad4e572c35162f4578c90"
 "checksum env_logger 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)" = "15abd780e45b3ea4f76b4e9a26ff4843258dd8a3eed2775a0e7368c2e7936c2f"
 "checksum env_logger 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)" = "e3856f1697098606fc6cb97a93de88ca3f3bc35bb878c725920e6e82ecf05e83"
diff --git a/src/bootstrap/native.rs b/src/bootstrap/native.rs
index dea1a607255..62eed8be3cc 100644
--- a/src/bootstrap/native.rs
+++ b/src/bootstrap/native.rs
@@ -18,6 +18,7 @@
 //! LLVM and compiler-rt are essentially just wired up to everything else to
 //! ensure that they're always in place if needed.
 
+use std::env;
 use std::fs::{self, File};
 use std::io::{Read, Write};
 use std::path::Path;
@@ -145,6 +146,10 @@ pub fn llvm(build: &Build, target: &str) {
         cfg.define("CMAKE_CXX_FLAGS", build.cflags(target).join(" "));
     }
 
+    if env::var_os("SCCACHE_ERROR_LOG").is_some() {
+        cfg.env("RUST_LOG", "sccache=debug");
+    }
+
     // FIXME: we don't actually need to build all LLVM tools and all LLVM
     //        libraries here, e.g. we just want a few components and a few
     //        tools. Figure out how to filter them down and only build the right
diff --git a/src/ci/docker/run.sh b/src/ci/docker/run.sh
index b5a713dc382..c418d427b15 100755
--- a/src/ci/docker/run.sh
+++ b/src/ci/docker/run.sh
@@ -39,7 +39,6 @@ if [ "$SCCACHE_BUCKET" != "" ]; then
     args="$args --env AWS_SECRET_ACCESS_KEY=$AWS_SECRET_ACCESS_KEY"
     args="$args --env SCCACHE_ERROR_LOG=/tmp/sccache/sccache.log"
     args="$args --env SCCACHE_LOG_LEVEL=debug"
-    args="$args --env RUST_LOG=sccache=debug"
     args="$args --volume $objdir/tmp:/tmp/sccache"
 else
     mkdir -p $HOME/.cache/sccache