Auto merge of #40347 - alexcrichton:rm-liblog, r=brson

Remove internal liblog

This commit deletes the internal liblog in favor of the implementation that
lives on crates.io. Similarly it's also setting a convention for adding crates
to the compiler. The main restriction right now is that we want compiler
implementation details to be unreachable from normal Rust code (e.g. requires a
feature), and by default everything in the sysroot is reachable via `extern
crate`.

The proposal here is to require that crates pulled in have these lines in their
`src/lib.rs`:

    #![cfg_attr(rustbuild, feature(staged_api, rustc_private))]
    #![cfg_attr(rustbuild, unstable(feature = "rustc_private", issue = "27812"))]

This'll mean that by default they're not using these attributes but when
compiled as part of the compiler they do a few things:

* Mark themselves as entirely unstable via the `staged_api` feature and the
  `#![unstable]` attribute.
* Allow usage of other unstable crates via `feature(rustc_private)` which is
  required if the crate relies on any other crates to compile (other than std).

38 files changed, 54 insertions, 1194 deletions

diff --git a/src/Cargo.lock b/src/Cargo.lock
index 9ae894061a6..a0b47f4f0b2 100644
--- a/src/Cargo.lock
+++ b/src/Cargo.lock
@@ -147,7 +147,7 @@ dependencies = [
 name = "compiletest"
 version = "0.0.0"
 dependencies = [
- "env_logger 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "env_logger 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "filetime 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-serialize 0.3.23 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -164,14 +164,6 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "env_logger"
-version = "0.3.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "log 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
-[[package]]
-name = "env_logger"
 version = "0.4.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
@@ -272,10 +264,6 @@ version = "0.1.0"
 
 [[package]]
 name = "log"
-version = "0.0.0"
-
-[[package]]
-name = "log"
 version = "0.3.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
@@ -439,7 +427,7 @@ dependencies = [
  "arena 0.0.0",
  "fmt_macros 0.0.0",
  "graphviz 0.0.0",
- "log 0.0.0",
+ "log 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc_back 0.0.0",
  "rustc_bitflags 0.0.0",
  "rustc_const_math 0.0.0",
@@ -479,7 +467,7 @@ dependencies = [
 name = "rustc_back"
 version = "0.0.0"
 dependencies = [
- "log 0.0.0",
+ "log 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "serialize 0.0.0",
  "syntax 0.0.0",
 ]
@@ -493,7 +481,7 @@ name = "rustc_borrowck"
 version = "0.0.0"
 dependencies = [
  "graphviz 0.0.0",
- "log 0.0.0",
+ "log 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc 0.0.0",
  "rustc_data_structures 0.0.0",
  "rustc_errors 0.0.0",
@@ -508,7 +496,7 @@ version = "0.0.0"
 dependencies = [
  "arena 0.0.0",
  "graphviz 0.0.0",
- "log 0.0.0",
+ "log 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc 0.0.0",
  "rustc_back 0.0.0",
  "rustc_const_math 0.0.0",
@@ -530,7 +518,7 @@ dependencies = [
 name = "rustc_data_structures"
 version = "0.0.0"
 dependencies = [
- "log 0.0.0",
+ "log 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "serialize 0.0.0",
 ]
 
@@ -539,8 +527,9 @@ name = "rustc_driver"
 version = "0.0.0"
 dependencies = [
  "arena 0.0.0",
+ "env_logger 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "graphviz 0.0.0",
- "log 0.0.0",
+ "log 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "proc_macro_plugin 0.0.0",
  "rustc 0.0.0",
  "rustc_back 0.0.0",
@@ -579,7 +568,7 @@ name = "rustc_incremental"
 version = "0.0.0"
 dependencies = [
  "graphviz 0.0.0",
- "log 0.0.0",
+ "log 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc 0.0.0",
  "rustc_data_structures 0.0.0",
  "serialize 0.0.0",
@@ -591,7 +580,7 @@ dependencies = [
 name = "rustc_lint"
 version = "0.0.0"
 dependencies = [
- "log 0.0.0",
+ "log 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc 0.0.0",
  "rustc_back 0.0.0",
  "rustc_const_eval 0.0.0",
@@ -623,7 +612,7 @@ name = "rustc_metadata"
 version = "0.0.0"
 dependencies = [
  "flate 0.0.0",
- "log 0.0.0",
+ "log 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "proc_macro 0.0.0",
  "rustc 0.0.0",
  "rustc_back 0.0.0",
@@ -642,7 +631,7 @@ name = "rustc_mir"
 version = "0.0.0"
 dependencies = [
  "graphviz 0.0.0",
- "log 0.0.0",
+ "log 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc 0.0.0",
  "rustc_bitflags 0.0.0",
  "rustc_const_eval 0.0.0",
@@ -666,7 +655,7 @@ dependencies = [
 name = "rustc_passes"
 version = "0.0.0"
 dependencies = [
- "log 0.0.0",
+ "log 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc 0.0.0",
  "rustc_const_eval 0.0.0",
  "rustc_const_math 0.0.0",
@@ -705,7 +694,7 @@ name = "rustc_resolve"
 version = "0.0.0"
 dependencies = [
  "arena 0.0.0",
- "log 0.0.0",
+ "log 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc 0.0.0",
  "rustc_errors 0.0.0",
  "syntax 0.0.0",
@@ -716,7 +705,7 @@ dependencies = [
 name = "rustc_save_analysis"
 version = "0.0.0"
 dependencies = [
- "log 0.0.0",
+ "log 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "rls-data 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rls-span 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc 0.0.0",
@@ -730,7 +719,7 @@ name = "rustc_trans"
 version = "0.0.0"
 dependencies = [
  "flate 0.0.0",
- "log 0.0.0",
+ "log 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc 0.0.0",
  "rustc_back 0.0.0",
  "rustc_bitflags 0.0.0",
@@ -762,7 +751,7 @@ version = "0.0.0"
 dependencies = [
  "arena 0.0.0",
  "fmt_macros 0.0.0",
- "log 0.0.0",
+ "log 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc 0.0.0",
  "rustc_back 0.0.0",
  "rustc_const_eval 0.0.0",
@@ -780,8 +769,9 @@ version = "0.0.0"
 dependencies = [
  "arena 0.0.0",
  "build_helper 0.1.0",
+ "env_logger 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "gcc 0.3.44 (registry+https://github.com/rust-lang/crates.io-index)",
- "log 0.0.0",
+ "log 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc 0.0.0",
  "rustc_back 0.0.0",
  "rustc_const_eval 0.0.0",
@@ -857,7 +847,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 name = "syntax"
 version = "0.0.0"
 dependencies = [
- "log 0.0.0",
+ "log 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc_bitflags 0.0.0",
  "rustc_data_structures 0.0.0",
  "rustc_errors 0.0.0",
@@ -870,7 +860,7 @@ name = "syntax_ext"
 version = "0.0.0"
 dependencies = [
  "fmt_macros 0.0.0",
- "log 0.0.0",
+ "log 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "proc_macro 0.0.0",
  "rustc_errors 0.0.0",
  "syntax 0.0.0",
@@ -996,7 +986,6 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum clap 2.21.1 (registry+https://github.com/rust-lang/crates.io-index)" = "74a80f603221c9cd9aa27a28f52af452850051598537bb6b359c38a7d61e5cda"
 "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"
 "checksum filetime 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)" = "5363ab8e4139b8568a6237db5248646e5a8a2f89bd5ccb02092182b11fd3e922"
 "checksum gcc 0.3.44 (registry+https://github.com/rust-lang/crates.io-index)" = "a32cd40070d7611ab76343dcb3204b2bb28c8a9450989a83a3d590248142f439"
diff --git a/src/liblog/Cargo.toml b/src/liblog/Cargo.toml
deleted file mode 100644
index 31a862478d0..00000000000
--- a/src/liblog/Cargo.toml
+++ /dev/null
@@ -1,9 +0,0 @@
-[package]
-authors = ["The Rust Project Developers"]
-name = "log"
-version = "0.0.0"
-
-[lib]
-name = "log"
-path = "lib.rs"
-crate-type = ["dylib", "rlib"]
diff --git a/src/liblog/directive.rs b/src/liblog/directive.rs
deleted file mode 100644
index eb50d6e6135..00000000000
--- a/src/liblog/directive.rs
+++ /dev/null
@@ -1,193 +0,0 @@
-// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-use std::ascii::AsciiExt;
-use std::cmp;
-
-#[derive(Debug, Clone)]
-pub struct LogDirective {
-    pub name: Option<String>,
-    pub level: u32,
-}
-
-pub const LOG_LEVEL_NAMES: [&'static str; 5] = ["ERROR", "WARN", "INFO", "DEBUG", "TRACE"];
-
-/// Parse an individual log level that is either a number or a symbolic log level
-fn parse_log_level(level: &str) -> Option<u32> {
-    level.parse::<u32>()
-        .ok()
-        .or_else(|| {
-            let pos = LOG_LEVEL_NAMES.iter().position(|&name| name.eq_ignore_ascii_case(level));
-            pos.map(|p| p as u32 + 1)
-        })
-        .map(|p| cmp::min(p, ::MAX_LOG_LEVEL))
-}
-
-/// Parse a logging specification string (e.g: "crate1,crate2::mod3,crate3::x=1/foo")
-/// and return a vector with log directives.
-///
-/// Valid log levels are 0-255, with the most likely ones being 1-4 (defined in
-/// std::).  Also supports string log levels of error, warn, info, and debug
-pub fn parse_logging_spec(spec: &str) -> (Vec<LogDirective>, Option<String>) {
-    let mut dirs = Vec::new();
-
-    let mut parts = spec.split('/');
-    let mods = parts.next();
-    let filter = parts.next();
-    if parts.next().is_some() {
-        println!("warning: invalid logging spec '{}', ignoring it (too many '/'s)",
-                 spec);
-        return (dirs, None);
-    }
-    if let Some(m) = mods {
-        for s in m.split(',') {
-            if s.is_empty() {
-                continue;
-            }
-            let mut parts = s.split('=');
-            let (log_level, name) =
-                match (parts.next(), parts.next().map(|s| s.trim()), parts.next()) {
-                    (Some(part0), None, None) => {
-                        // if the single argument is a log-level string or number,
-                        // treat that as a global fallback
-                        match parse_log_level(part0) {
-                            Some(num) => (num, None),
-                            None => (::MAX_LOG_LEVEL, Some(part0)),
-                        }
-                    }
-                    (Some(part0), Some(""), None) => (::MAX_LOG_LEVEL, Some(part0)),
-                    (Some(part0), Some(part1), None) => {
-                        match parse_log_level(part1) {
-                            Some(num) => (num, Some(part0)),
-                            _ => {
-                                println!("warning: invalid logging spec '{}', ignoring it", part1);
-                                continue;
-                            }
-                        }
-                    }
-                    _ => {
-                        println!("warning: invalid logging spec '{}', ignoring it", s);
-                        continue;
-                    }
-                };
-            dirs.push(LogDirective {
-                name: name.map(str::to_owned),
-                level: log_level,
-            });
-        }
-    }
-
-    (dirs, filter.map(str::to_owned))
-}
-
-#[cfg(test)]
-mod tests {
-    use super::parse_logging_spec;
-
-    #[test]
-    fn parse_logging_spec_valid() {
-        let (dirs, filter) = parse_logging_spec("crate1::mod1=1,crate1::mod2,crate2=4");
-        assert_eq!(dirs.len(), 3);
-        assert_eq!(dirs[0].name, Some("crate1::mod1".to_owned()));
-        assert_eq!(dirs[0].level, 1);
-
-        assert_eq!(dirs[1].name, Some("crate1::mod2".to_owned()));
-        assert_eq!(dirs[1].level, ::MAX_LOG_LEVEL);
-
-        assert_eq!(dirs[2].name, Some("crate2".to_owned()));
-        assert_eq!(dirs[2].level, 4);
-        assert!(filter.is_none());
-    }
-
-    #[test]
-    fn parse_logging_spec_invalid_crate() {
-        // test parse_logging_spec with multiple = in specification
-        let (dirs, filter) = parse_logging_spec("crate1::mod1=1=2,crate2=4");
-        assert_eq!(dirs.len(), 1);
-        assert_eq!(dirs[0].name, Some("crate2".to_owned()));
-        assert_eq!(dirs[0].level, 4);
-        assert!(filter.is_none());
-    }
-
-    #[test]
-    fn parse_logging_spec_invalid_log_level() {
-        // test parse_logging_spec with 'noNumber' as log level
-        let (dirs, filter) = parse_logging_spec("crate1::mod1=noNumber,crate2=4");
-        assert_eq!(dirs.len(), 1);
-        assert_eq!(dirs[0].name, Some("crate2".to_owned()));
-        assert_eq!(dirs[0].level, 4);
-        assert!(filter.is_none());
-    }
-
-    #[test]
-    fn parse_logging_spec_string_log_level() {
-        // test parse_logging_spec with 'warn' as log level
-        let (dirs, filter) = parse_logging_spec("crate1::mod1=wrong,crate2=warn");
-        assert_eq!(dirs.len(), 1);
-        assert_eq!(dirs[0].name, Some("crate2".to_owned()));
-        assert_eq!(dirs[0].level, ::WARN);
-        assert!(filter.is_none());
-    }
-
-    #[test]
-    fn parse_logging_spec_empty_log_level() {
-        // test parse_logging_spec with '' as log level
-        let (dirs, filter) = parse_logging_spec("crate1::mod1=wrong,crate2=");
-        assert_eq!(dirs.len(), 1);
-        assert_eq!(dirs[0].name, Some("crate2".to_owned()));
-        assert_eq!(dirs[0].level, ::MAX_LOG_LEVEL);
-        assert!(filter.is_none());
-    }
-
-    #[test]
-    fn parse_logging_spec_global() {
-        // test parse_logging_spec with no crate
-        let (dirs, filter) = parse_logging_spec("warn,crate2=4");
-        assert_eq!(dirs.len(), 2);
-        assert_eq!(dirs[0].name, None);
-        assert_eq!(dirs[0].level, 2);
-        assert_eq!(dirs[1].name, Some("crate2".to_owned()));
-        assert_eq!(dirs[1].level, 4);
-        assert!(filter.is_none());
-    }
-
-    #[test]
-    fn parse_logging_spec_valid_filter() {
-        let (dirs, filter) = parse_logging_spec("crate1::mod1=1,crate1::mod2,crate2=4/abc");
-        assert_eq!(dirs.len(), 3);
-        assert_eq!(dirs[0].name, Some("crate1::mod1".to_owned()));
-        assert_eq!(dirs[0].level, 1);
-
-        assert_eq!(dirs[1].name, Some("crate1::mod2".to_owned()));
-        assert_eq!(dirs[1].level, ::MAX_LOG_LEVEL);
-
-        assert_eq!(dirs[2].name, Some("crate2".to_owned()));
-        assert_eq!(dirs[2].level, 4);
-        assert!(filter.is_some() && filter.unwrap().to_owned() == "abc");
-    }
-
-    #[test]
-    fn parse_logging_spec_invalid_crate_filter() {
-        let (dirs, filter) = parse_logging_spec("crate1::mod1=1=2,crate2=4/a.c");
-        assert_eq!(dirs.len(), 1);
-        assert_eq!(dirs[0].name, Some("crate2".to_owned()));
-        assert_eq!(dirs[0].level, 4);
-        assert!(filter.is_some() && filter.unwrap().to_owned() == "a.c");
-    }
-
-    #[test]
-    fn parse_logging_spec_empty_with_filter() {
-        let (dirs, filter) = parse_logging_spec("crate1/a*c");
-        assert_eq!(dirs.len(), 1);
-        assert_eq!(dirs[0].name, Some("crate1".to_owned()));
-        assert_eq!(dirs[0].level, ::MAX_LOG_LEVEL);
-        assert!(filter.is_some() && filter.unwrap().to_owned() == "a*c");
-    }
-}
diff --git a/src/liblog/lib.rs b/src/liblog/lib.rs
deleted file mode 100644
index 057df647c72..00000000000
--- a/src/liblog/lib.rs
+++ /dev/null
@@ -1,506 +0,0 @@
-// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-//! Utilities for program-wide and customizable logging
-//!
-//! # Examples
-//!
-//! ```
-//! # #![feature(rustc_private)]
-//! #[macro_use] extern crate log;
-//!
-//! fn main() {
-//!     debug!("this is a debug {:?}", "message");
-//!     error!("this is printed by default");
-//!
-//!     if log_enabled!(log::INFO) {
-//!         let x = 3 * 4; // expensive computation
-//!         info!("the answer was: {:?}", x);
-//!     }
-//! }
-//! ```
-//!
-//! Assumes the binary is `main`:
-//!
-//! ```{.bash}
-//! $ RUST_LOG=error ./main
-//! ERROR:main: this is printed by default
-//! ```
-//!
-//! ```{.bash}
-//! $ RUST_LOG=info ./main
-//! ERROR:main: this is printed by default
-//! INFO:main: the answer was: 12
-//! ```
-//!
-//! ```{.bash}
-//! $ RUST_LOG=debug ./main
-//! DEBUG:main: this is a debug message
-//! ERROR:main: this is printed by default
-//! INFO:main: the answer was: 12
-//! ```
-//!
-//! You can also set the log level on a per module basis:
-//!
-//! ```{.bash}
-//! $ RUST_LOG=main=info ./main
-//! ERROR:main: this is printed by default
-//! INFO:main: the answer was: 12
-//! ```
-//!
-//! And enable all logging:
-//!
-//! ```{.bash}
-//! $ RUST_LOG=main ./main
-//! DEBUG:main: this is a debug message
-//! ERROR:main: this is printed by default
-//! INFO:main: the answer was: 12
-//! ```
-//!
-//! # Logging Macros
-//!
-//! There are five macros that the logging subsystem uses:
-//!
-//! * `log!(level, ...)` - the generic logging macro, takes a level as a u32 and any
-//!                        related `format!` arguments
-//! * `debug!(...)` - a macro hard-wired to the log level of `DEBUG`
-//! * `info!(...)` - a macro hard-wired to the log level of `INFO`
-//! * `warn!(...)` - a macro hard-wired to the log level of `WARN`
-//! * `error!(...)` - a macro hard-wired to the log level of `ERROR`
-//!
-//! All of these macros use the same style of syntax as the `format!` syntax
-//! extension. Details about the syntax can be found in the documentation of
-//! `std::fmt` along with the Rust tutorial/manual.
-//!
-//! If you want to check at runtime if a given logging level is enabled (e.g. if the
-//! information you would want to log is expensive to produce), you can use the
-//! following macro:
-//!
-//! * `log_enabled!(level)` - returns true if logging of the given level is enabled
-//!
-//! # Enabling logging
-//!
-//! Log levels are controlled on a per-module basis, and by default all logging is
-//! disabled except for `error!` (a log level of 1). Logging is controlled via the
-//! `RUST_LOG` environment variable. The value of this environment variable is a
-//! comma-separated list of logging directives. A logging directive is of the form:
-//!
-//! ```text
-//! path::to::module=log_level
-//! ```
-//!
-//! The path to the module is rooted in the name of the crate it was compiled for,
-//! so if your program is contained in a file `hello.rs`, for example, to turn on
-//! logging for this file you would use a value of `RUST_LOG=hello`.
-//! Furthermore, this path is a prefix-search, so all modules nested in the
-//! specified module will also have logging enabled.
-//!
-//! The actual `log_level` is optional to specify. If omitted, all logging will be
-//! enabled. If specified, the it must be either a numeric in the range of 1-255, or
-//! it must be one of the strings `debug`, `error`, `info`, or `warn`. If a numeric
-//! is specified, then all logging less than or equal to that numeral is enabled.
-//! For example, if logging level 3 is active, error, warn, and info logs will be
-//! printed, but debug will be omitted.
-//!
-//! As the log level for a module is optional, the module to enable logging for is
-//! also optional. If only a `log_level` is provided, then the global log level for
-//! all modules is set to this value.
-//!
-//! Some examples of valid values of `RUST_LOG` are:
-//!
-//! * `hello` turns on all logging for the 'hello' module
-//! * `info` turns on all info logging
-//! * `hello=debug` turns on debug logging for 'hello'
-//! * `hello=3` turns on info logging for 'hello'
-//! * `hello,std::option` turns on hello, and std's option logging
-//! * `error,hello=warn` turn on global error logging and also warn for hello
-//!
-//! # Filtering results
-//!
-//! A RUST_LOG directive may include a string filter. The syntax is to append
-//! `/` followed by a string. Each message is checked against the string and is
-//! only logged if it contains the string. Note that the matching is done after
-//! formatting the log string but before adding any logging meta-data. There is
-//! a single filter for all modules.
-//!
-//! Some examples:
-//!
-//! * `hello/foo` turns on all logging for the 'hello' module where the log message
-//! includes 'foo'.
-//! * `info/f.o` turns on all info logging where the log message includes 'foo',
-//! 'f1o', 'fao', etc.
-//! * `hello=debug/foo*foo` turns on debug logging for 'hello' where the log
-//! message includes 'foofoo' or 'fofoo' or 'fooooooofoo', etc.
-//! * `error,hello=warn/[0-9] scopes` turn on global error logging and also warn for
-//!  hello. In both cases the log message must include a single digit number
-//!  followed by 'scopes'
-//!
-//! # Performance and Side Effects
-//!
-//! Each of these macros will expand to code similar to:
-//!
-//! ```rust,ignore
-//! if log_level <= my_module_log_level() {
-//!     ::log::log(log_level, format!(...));
-//! }
-//! ```
-//!
-//! What this means is that each of these macros are very cheap at runtime if
-//! they're turned off (just a load and an integer comparison). This also means that
-//! if logging is disabled, none of the components of the log will be executed.
-
-#![crate_name = "log"]
-#![unstable(feature = "rustc_private",
-            reason = "use the crates.io `log` library instead",
-            issue = "27812")]
-#![crate_type = "rlib"]
-#![crate_type = "dylib"]
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-       html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-       html_root_url = "https://doc.rust-lang.org/nightly/",
-       html_playground_url = "https://play.rust-lang.org/",
-       test(attr(deny(warnings))))]
-#![deny(missing_docs)]
-#![deny(warnings)]
-
-#![feature(staged_api)]
-
-use std::cell::RefCell;
-use std::fmt;
-use std::io::{self, Stderr};
-use std::io::prelude::*;
-use std::mem;
-use std::env;
-use std::slice;
-use std::sync::{Mutex, ONCE_INIT, Once};
-
-use directive::LOG_LEVEL_NAMES;
-
-#[macro_use]
-pub mod macros;
-
-mod directive;
-
-/// Maximum logging level of a module that can be specified. Common logging
-/// levels are found in the DEBUG/INFO/WARN/ERROR constants.
-pub const MAX_LOG_LEVEL: u32 = 255;
-
-/// The default logging level of a crate if no other is specified.
-const DEFAULT_LOG_LEVEL: u32 = 1;
-
-static mut LOCK: *mut Mutex<(Vec<directive::LogDirective>, Option<String>)> = 0 as *mut _;
-
-/// An unsafe constant that is the maximum logging level of any module
-/// specified. This is the first line of defense to determining whether a
-/// logging statement should be run.
-static mut LOG_LEVEL: u32 = MAX_LOG_LEVEL;
-
-/// Debug log level
-pub const DEBUG: u32 = 4;
-/// Info log level
-pub const INFO: u32 = 3;
-/// Warn log level
-pub const WARN: u32 = 2;
-/// Error log level
-pub const ERROR: u32 = 1;
-
-thread_local! {
-    static LOCAL_LOGGER: RefCell<Option<Box<Logger + Send>>> = {
-        RefCell::new(None)
-    }
-}
-
-/// A trait used to represent an interface to a thread-local logger. Each thread
-/// can have its own custom logger which can respond to logging messages
-/// however it likes.
-pub trait Logger {
-    /// Logs a single message described by the `record`.
-    fn log(&mut self, record: &LogRecord);
-}
-
-struct DefaultLogger {
-    handle: Stderr,
-}
-
-/// Wraps the log level with fmt implementations.
-#[derive(Copy, Clone, PartialEq, PartialOrd, Debug)]
-pub struct LogLevel(pub u32);
-
-impl fmt::Display for LogLevel {
-    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        let LogLevel(level) = *self;
-        match LOG_LEVEL_NAMES.get(level as usize - 1) {
-            Some(ref name) => fmt::Display::fmt(name, fmt),
-            None => fmt::Display::fmt(&level, fmt),
-        }
-    }
-}
-
-impl Logger for DefaultLogger {
-    fn log(&mut self, record: &LogRecord) {
-        match writeln!(&mut self.handle,
-                       "{}:{}: {}",
-                       record.level,
-                       record.module_path,
-                       record.args) {
-            Err(e) => panic!("failed to log: {:?}", e),
-            Ok(()) => {}
-        }
-    }
-}
-
-impl Drop for DefaultLogger {
-    fn drop(&mut self) {
-        // FIXME(#12628): is panicking the right thing to do?
-        match self.handle.flush() {
-            Err(e) => panic!("failed to flush a logger: {:?}", e),
-            Ok(()) => {}
-        }
-    }
-}
-
-/// This function is called directly by the compiler when using the logging
-/// macros. This function does not take into account whether the log level
-/// specified is active or not, it will always log something if this method is
-/// called.
-///
-/// It is not recommended to call this function directly, rather it should be
-/// invoked through the logging family of macros.
-#[doc(hidden)]
-pub fn log(level: u32, loc: &'static LogLocation, args: fmt::Arguments) {
-    // Test the literal string from args against the current filter, if there
-    // is one.
-    unsafe {
-        let filter = (*LOCK).lock().unwrap();
-        if let Some(ref filter) = filter.1 {
-            if !args.to_string().contains(filter) {
-                return;
-            }
-        }
-    }
-
-    // Completely remove the local logger from TLS in case anyone attempts to
-    // frob the slot while we're doing the logging. This will destroy any logger
-    // set during logging.
-    let logger = LOCAL_LOGGER.with(|s| s.borrow_mut().take());
-    let mut logger = logger.unwrap_or_else(|| Box::new(DefaultLogger { handle: io::stderr() }));
-    logger.log(&LogRecord {
-        level: LogLevel(level),
-        args: args,
-        file: loc.file,
-        module_path: loc.module_path,
-        line: loc.line,
-    });
-    set_logger(logger);
-}
-
-/// Getter for the global log level. This is a function so that it can be called
-/// safely
-#[doc(hidden)]
-#[inline(always)]
-pub fn log_level() -> u32 {
-    unsafe { LOG_LEVEL }
-}
-
-/// Replaces the thread-local logger with the specified logger, returning the old
-/// logger.
-pub fn set_logger(logger: Box<Logger + Send>) -> Option<Box<Logger + Send>> {
-    LOCAL_LOGGER.with(|slot| mem::replace(&mut *slot.borrow_mut(), Some(logger)))
-}
-
-/// A LogRecord is created by the logging macros, and passed as the only
-/// argument to Loggers.
-#[derive(Debug)]
-pub struct LogRecord<'a> {
-    /// The module path of where the LogRecord originated.
-    pub module_path: &'a str,
-
-    /// The LogLevel of this record.
-    pub level: LogLevel,
-
-    /// The arguments from the log line.
-    pub args: fmt::Arguments<'a>,
-
-    /// The file of where the LogRecord originated.
-    pub file: &'a str,
-
-    /// The line number of where the LogRecord originated.
-    pub line: u32,
-}
-
-#[doc(hidden)]
-#[derive(Copy, Clone)]
-pub struct LogLocation {
-    pub module_path: &'static str,
-    pub file: &'static str,
-    pub line: u32,
-}
-
-/// Tests whether a given module's name is enabled for a particular level of
-/// logging. This is the second layer of defense about determining whether a
-/// module's log statement should be emitted or not.
-#[doc(hidden)]
-pub fn mod_enabled(level: u32, module: &str) -> bool {
-    static INIT: Once = ONCE_INIT;
-    INIT.call_once(init);
-
-    // It's possible for many threads are in this function, only one of them
-    // will perform the global initialization, but all of them will need to check
-    // again to whether they should really be here or not. Hence, despite this
-    // check being expanded manually in the logging macro, this function checks
-    // the log level again.
-    if level > unsafe { LOG_LEVEL } {
-        return false;
-    }
-
-    // This assertion should never get tripped unless we're in an at_exit
-    // handler after logging has been torn down and a logging attempt was made.
-
-    unsafe {
-        let directives = (*LOCK).lock().unwrap();
-        enabled(level, module, directives.0.iter())
-    }
-}
-
-fn enabled(level: u32, module: &str, iter: slice::Iter<directive::LogDirective>) -> bool {
-    // Search for the longest match, the vector is assumed to be pre-sorted.
-    for directive in iter.rev() {
-        match directive.name {
-            Some(ref name) if !module.starts_with(&name[..]) => {}
-            Some(..) | None => return level <= directive.level,
-        }
-    }
-    level <= DEFAULT_LOG_LEVEL
-}
-
-/// Initialize logging for the current process.
-///
-/// This is not threadsafe at all, so initialization is performed through a
-/// `Once` primitive (and this function is called from that primitive).
-fn init() {
-    let (mut directives, filter) = match env::var("RUST_LOG") {
-        Ok(spec) => directive::parse_logging_spec(&spec[..]),
-        Err(..) => (Vec::new(), None),
-    };
-
-    // Sort the provided directives by length of their name, this allows a
-    // little more efficient lookup at runtime.
-    directives.sort_by(|a, b| {
-        let alen = a.name.as_ref().map(|a| a.len()).unwrap_or(0);
-        let blen = b.name.as_ref().map(|b| b.len()).unwrap_or(0);
-        alen.cmp(&blen)
-    });
-
-    let max_level = {
-        let max = directives.iter().max_by_key(|d| d.level);
-        max.map(|d| d.level).unwrap_or(DEFAULT_LOG_LEVEL)
-    };
-
-    unsafe {
-        LOG_LEVEL = max_level;
-
-        assert!(LOCK.is_null());
-        LOCK = Box::into_raw(Box::new(Mutex::new((directives, filter))));
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::enabled;
-    use directive::LogDirective;
-
-    #[test]
-    fn match_full_path() {
-        let dirs = [LogDirective {
-                        name: Some("crate2".to_string()),
-                        level: 3,
-                    },
-                    LogDirective {
-                        name: Some("crate1::mod1".to_string()),
-                        level: 2,
-                    }];
-        assert!(enabled(2, "crate1::mod1", dirs.iter()));
-        assert!(!enabled(3, "crate1::mod1", dirs.iter()));
-        assert!(enabled(3, "crate2", dirs.iter()));
-        assert!(!enabled(4, "crate2", dirs.iter()));
-    }
-
-    #[test]
-    fn no_match() {
-        let dirs = [LogDirective {
-                        name: Some("crate2".to_string()),
-                        level: 3,
-                    },
-                    LogDirective {
-                        name: Some("crate1::mod1".to_string()),
-                        level: 2,
-                    }];
-        assert!(!enabled(2, "crate3", dirs.iter()));
-    }
-
-    #[test]
-    fn match_beginning() {
-        let dirs = [LogDirective {
-                        name: Some("crate2".to_string()),
-                        level: 3,
-                    },
-                    LogDirective {
-                        name: Some("crate1::mod1".to_string()),
-                        level: 2,
-                    }];
-        assert!(enabled(3, "crate2::mod1", dirs.iter()));
-    }
-
-    #[test]
-    fn match_beginning_longest_match() {
-        let dirs = [LogDirective {
-                        name: Some("crate2".to_string()),
-                        level: 3,
-                    },
-                    LogDirective {
-                        name: Some("crate2::mod".to_string()),
-                        level: 4,
-                    },
-                    LogDirective {
-                        name: Some("crate1::mod1".to_string()),
-                        level: 2,
-                    }];
-        assert!(enabled(4, "crate2::mod1", dirs.iter()));
-        assert!(!enabled(4, "crate2", dirs.iter()));
-    }
-
-    #[test]
-    fn match_default() {
-        let dirs = [LogDirective {
-                        name: None,
-                        level: 3,
-                    },
-                    LogDirective {
-                        name: Some("crate1::mod1".to_string()),
-                        level: 2,
-                    }];
-        assert!(enabled(2, "crate1::mod1", dirs.iter()));
-        assert!(enabled(3, "crate2::mod2", dirs.iter()));
-    }
-
-    #[test]
-    fn zero_level() {
-        let dirs = [LogDirective {
-                        name: None,
-                        level: 3,
-                    },
-                    LogDirective {
-                        name: Some("crate1::mod1".to_string()),
-                        level: 0,
-                    }];
-        assert!(!enabled(1, "crate1::mod1", dirs.iter()));
-        assert!(enabled(3, "crate2::mod2", dirs.iter()));
-    }
-}
diff --git a/src/liblog/macros.rs b/src/liblog/macros.rs
deleted file mode 100644
index 803a2df9ccc..00000000000
--- a/src/liblog/macros.rs
+++ /dev/null
@@ -1,205 +0,0 @@
-// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-//! Logging macros
-
-/// The standard logging macro
-///
-/// This macro will generically log over a provided level (of type u32) with a
-/// format!-based argument list. See documentation in `std::fmt` for details on
-/// how to use the syntax.
-///
-/// # Examples
-///
-/// ```
-/// # #![feature(rustc_private)]
-/// #[macro_use] extern crate log;
-///
-/// fn main() {
-///     log!(log::WARN, "this is a warning {}", "message");
-///     log!(log::DEBUG, "this is a debug message");
-///     log!(6, "this is a custom logging level: {level}", level=6);
-/// }
-/// ```
-///
-/// Assumes the binary is `main`:
-///
-/// ```{.bash}
-/// $ RUST_LOG=warn ./main
-/// WARN:main: this is a warning message
-/// ```
-///
-/// ```{.bash}
-/// $ RUST_LOG=debug ./main
-/// DEBUG:main: this is a debug message
-/// WARN:main: this is a warning message
-/// ```
-///
-/// ```{.bash}
-/// $ RUST_LOG=6 ./main
-/// DEBUG:main: this is a debug message
-/// WARN:main: this is a warning message
-/// 6:main: this is a custom logging level: 6
-/// ```
-#[macro_export]
-macro_rules! log {
-    ($lvl:expr, $($arg:tt)+) => ({
-        static LOC: ::log::LogLocation = ::log::LogLocation {
-            line: line!(),
-            file: file!(),
-            module_path: module_path!(),
-        };
-        let lvl = $lvl;
-        if log_enabled!(lvl) {
-            ::log::log(lvl, &LOC, format_args!($($arg)+))
-        }
-    })
-}
-
-/// A convenience macro for logging at the error log level.
-///
-/// # Examples
-///
-/// ```
-/// # #![feature(rustc_private)]
-/// #[macro_use] extern crate log;
-///
-/// fn main() {
-///     let error = 3;
-///     error!("the build has failed with error code: {}", error);
-/// }
-/// ```
-///
-/// Assumes the binary is `main`:
-///
-/// ```{.bash}
-/// $ RUST_LOG=error ./main
-/// ERROR:main: the build has failed with error code: 3
-/// ```
-///
-#[macro_export]
-macro_rules! error {
-    ($($arg:tt)*) => (log!(::log::ERROR, $($arg)*))
-}
-
-/// A convenience macro for logging at the warning log level.
-///
-/// # Examples
-///
-/// ```
-/// # #![feature(rustc_private)]
-/// #[macro_use] extern crate log;
-///
-/// fn main() {
-///     let code = 3;
-///     warn!("you may like to know that a process exited with: {}", code);
-/// }
-/// ```
-///
-/// Assumes the binary is `main`:
-///
-/// ```{.bash}
-/// $ RUST_LOG=warn ./main
-/// WARN:main: you may like to know that a process exited with: 3
-/// ```
-#[macro_export]
-macro_rules! warn {
-    ($($arg:tt)*) => (log!(::log::WARN, $($arg)*))
-}
-
-/// A convenience macro for logging at the info log level.
-///
-/// # Examples
-///
-/// ```
-/// # #![feature(rustc_private)]
-/// #[macro_use] extern crate log;
-///
-/// fn main() {
-///     let ret = 3;
-///     info!("this function is about to return: {}", ret);
-/// }
-/// ```
-///
-/// Assumes the binary is `main`:
-///
-/// ```{.bash}
-/// $ RUST_LOG=info ./main
-/// INFO:main: this function is about to return: 3
-/// ```
-#[macro_export]
-macro_rules! info {
-    ($($arg:tt)*) => (log!(::log::INFO, $($arg)*))
-}
-
-/// A convenience macro for logging at the debug log level. This macro will
-/// be omitted at compile time in an optimized build unless `-C debug-assertions`
-/// is passed to the compiler.
-///
-/// # Examples
-///
-/// ```
-/// # #![feature(rustc_private)]
-/// #[macro_use] extern crate log;
-///
-/// fn main() {
-///     debug!("x = {x}, y = {y}", x=10, y=20);
-/// }
-/// ```
-///
-/// Assumes the binary is `main`:
-///
-/// ```{.bash}
-/// $ RUST_LOG=debug ./main
-/// DEBUG:main: x = 10, y = 20
-/// ```
-#[macro_export]
-macro_rules! debug {
-    ($($arg:tt)*) => (if cfg!(debug_assertions) { log!(::log::DEBUG, $($arg)*) })
-}
-
-/// A macro to test whether a log level is enabled for the current module.
-///
-/// # Examples
-///
-/// ```
-/// # #![feature(rustc_private)]
-/// #[macro_use] extern crate log;
-///
-/// struct Point { x: i32, y: i32 }
-/// fn some_expensive_computation() -> Point { Point { x: 1, y: 2 } }
-///
-/// fn main() {
-///     if log_enabled!(log::DEBUG) {
-///         let x = some_expensive_computation();
-///         debug!("x.x = {}, x.y = {}", x.x, x.y);
-///     }
-/// }
-/// ```
-///
-/// Assumes the binary is `main`:
-///
-/// ```{.bash}
-/// $ RUST_LOG=error ./main
-/// ```
-///
-/// ```{.bash}
-/// $ RUST_LOG=debug ./main
-/// DEBUG:main: x.x = 1, x.y = 2
-/// ```
-#[macro_export]
-macro_rules! log_enabled {
-    ($lvl:expr) => ({
-        let lvl = $lvl;
-        (lvl != ::log::DEBUG || cfg!(debug_assertions)) &&
-        lvl <= ::log::log_level() &&
-        ::log::mod_enabled(lvl, module_path!())
-    })
-}
diff --git a/src/librustc/Cargo.toml b/src/librustc/Cargo.toml
index 5d53c60ad7f..fa217acd9f9 100644
--- a/src/librustc/Cargo.toml
+++ b/src/librustc/Cargo.toml
@@ -12,7 +12,7 @@ crate-type = ["dylib"]
 arena = { path = "../libarena" }
 fmt_macros = { path = "../libfmt_macros" }
 graphviz = { path = "../libgraphviz" }
-log = { path = "../liblog" }
+log = "0.3"
 rustc_back = { path = "../librustc_back" }
 rustc_bitflags = { path = "../librustc_bitflags" }
 rustc_const_math = { path = "../librustc_const_math" }
diff --git a/src/librustc/hir/map/mod.rs b/src/librustc/hir/map/mod.rs
index 583b3b848f3..d7aa36b24f9 100644
--- a/src/librustc/hir/map/mod.rs
+++ b/src/librustc/hir/map/mod.rs
@@ -948,7 +948,7 @@ pub fn map_crate<'hir>(forest: &'hir mut Forest,
     intravisit::walk_crate(&mut collector, &forest.krate);
     let map = collector.map;
 
-    if log_enabled!(::log::DEBUG) {
+    if log_enabled!(::log::LogLevel::Debug) {
         // This only makes sense for ordered stores; note the
         // enumerate to count the number of entries.
         let (entries_less_1, _) = map.iter().filter(|&x| {
diff --git a/src/librustc/ty/item_path.rs b/src/librustc/ty/item_path.rs
index 874e032bc46..38699105290 100644
--- a/src/librustc/ty/item_path.rs
+++ b/src/librustc/ty/item_path.rs
@@ -202,7 +202,8 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         } else {
             // for local crates, check whether type info is
             // available; typeck might not have completed yet
-            self.maps.impl_trait_ref.borrow().contains_key(&impl_def_id)
+            self.maps.impl_trait_ref.borrow().contains_key(&impl_def_id) &&
+                self.maps.ty.borrow().contains_key(&impl_def_id)
         };
 
         if !use_types {
diff --git a/src/librustc_back/Cargo.toml b/src/librustc_back/Cargo.toml
index 85e861b405a..730abc54568 100644
--- a/src/librustc_back/Cargo.toml
+++ b/src/librustc_back/Cargo.toml
@@ -11,7 +11,7 @@ crate-type = ["dylib"]
 [dependencies]
 syntax = { path = "../libsyntax" }
 serialize = { path = "../libserialize" }
-log = { path = "../liblog" }
+log = "0.3"
 
 [features]
 jemalloc = []
diff --git a/src/librustc_borrowck/Cargo.toml b/src/librustc_borrowck/Cargo.toml
index d53318f1768..af99c0e9387 100644
--- a/src/librustc_borrowck/Cargo.toml
+++ b/src/librustc_borrowck/Cargo.toml
@@ -10,7 +10,7 @@ crate-type = ["dylib"]
 test = false
 
 [dependencies]
-log = { path = "../liblog" }
+log = "0.3"
 syntax = { path = "../libsyntax" }
 syntax_pos = { path = "../libsyntax_pos" }
 graphviz = { path = "../libgraphviz" }
diff --git a/src/librustc_const_eval/Cargo.toml b/src/librustc_const_eval/Cargo.toml
index 780b2c16a32..907410f74dc 100644
--- a/src/librustc_const_eval/Cargo.toml
+++ b/src/librustc_const_eval/Cargo.toml
@@ -10,7 +10,7 @@ crate-type = ["dylib"]
 
 [dependencies]
 arena = { path = "../libarena" }
-log = { path = "../liblog" }
+log = "0.3"
 rustc = { path = "../librustc" }
 rustc_back = { path = "../librustc_back" }
 rustc_const_math = { path = "../librustc_const_math" }
diff --git a/src/librustc_data_structures/Cargo.toml b/src/librustc_data_structures/Cargo.toml
index e2e16059d98..343b1ed68b8 100644
--- a/src/librustc_data_structures/Cargo.toml
+++ b/src/librustc_data_structures/Cargo.toml
@@ -9,5 +9,5 @@ path = "lib.rs"
 crate-type = ["dylib"]
 
 [dependencies]
-log = { path = "../liblog" }
+log = "0.3"
 serialize = { path = "../libserialize" }
diff --git a/src/librustc_driver/Cargo.toml b/src/librustc_driver/Cargo.toml
index caa5c8b7e00..5b5113caa8e 100644
--- a/src/librustc_driver/Cargo.toml
+++ b/src/librustc_driver/Cargo.toml
@@ -11,7 +11,8 @@ crate-type = ["dylib"]
 [dependencies]
 arena = { path = "../libarena" }
 graphviz = { path = "../libgraphviz" }
-log = { path = "../liblog" }
+log = { version = "0.3", features = ["release_max_level_info"] }
+env_logger = { version = "0.4", default-features = false }
 proc_macro_plugin = { path = "../libproc_macro_plugin" }
 rustc = { path = "../librustc" }
 rustc_back = { path = "../librustc_back" }
diff --git a/src/librustc_driver/driver.rs b/src/librustc_driver/driver.rs
index d37553d7d66..81095ad9f83 100644
--- a/src/librustc_driver/driver.rs
+++ b/src/librustc_driver/driver.rs
@@ -198,13 +198,13 @@ pub fn compile_input(sess: &Session,
 
             result?;
 
-            if log_enabled!(::log::INFO) {
+            if log_enabled!(::log::LogLevel::Info) {
                 println!("Pre-trans");
                 tcx.print_debug_stats();
             }
             let trans = phase_4_translate_to_llvm(tcx, analysis, &incremental_hashes_map);
 
-            if log_enabled!(::log::INFO) {
+            if log_enabled!(::log::LogLevel::Info) {
                 println!("Post-trans");
                 tcx.print_debug_stats();
             }
diff --git a/src/librustc_driver/lib.rs b/src/librustc_driver/lib.rs
index 62d75126557..68b9f85721a 100644
--- a/src/librustc_driver/lib.rs
+++ b/src/librustc_driver/lib.rs
@@ -35,6 +35,7 @@
 extern crate arena;
 extern crate getopts;
 extern crate graphviz;
+extern crate env_logger;
 extern crate libc;
 extern crate rustc;
 extern crate rustc_back;
@@ -1127,6 +1128,7 @@ pub fn diagnostics_registry() -> errors::registry::Registry {
 }
 
 pub fn main() {
+    env_logger::init().unwrap();
     let result = run(|| run_compiler(&env::args().collect::<Vec<_>>(),
                                      &mut RustcDefaultCalls,
                                      None,
diff --git a/src/librustc_incremental/Cargo.toml b/src/librustc_incremental/Cargo.toml
index e3ee7527545..7bf2efa4b88 100644
--- a/src/librustc_incremental/Cargo.toml
+++ b/src/librustc_incremental/Cargo.toml
@@ -13,6 +13,6 @@ graphviz = { path = "../libgraphviz" }
 rustc = { path = "../librustc" }
 rustc_data_structures = { path = "../librustc_data_structures" }
 serialize = { path = "../libserialize" }
-log = { path = "../liblog" }
+log = "0.3"
 syntax = { path = "../libsyntax" }
 syntax_pos = { path = "../libsyntax_pos" }
diff --git a/src/librustc_lint/Cargo.toml b/src/librustc_lint/Cargo.toml
index 4d5c0d7ba0a..c3c5461ff7c 100644
--- a/src/librustc_lint/Cargo.toml
+++ b/src/librustc_lint/Cargo.toml
@@ -10,7 +10,7 @@ crate-type = ["dylib"]
 test = false
 
 [dependencies]
-log = { path = "../liblog" }
+log = "0.3"
 rustc = { path = "../librustc" }
 rustc_back = { path = "../librustc_back" }
 rustc_const_eval = { path = "../librustc_const_eval" }
diff --git a/src/librustc_metadata/Cargo.toml b/src/librustc_metadata/Cargo.toml
index 6f7f03ca216..e8b90609273 100644
--- a/src/librustc_metadata/Cargo.toml
+++ b/src/librustc_metadata/Cargo.toml
@@ -10,7 +10,7 @@ crate-type = ["dylib"]
 
 [dependencies]
 flate = { path = "../libflate" }
-log = { path = "../liblog" }
+log = "0.3"
 proc_macro = { path = "../libproc_macro" }
 rustc = { path = "../librustc" }
 rustc_back = { path = "../librustc_back" }
diff --git a/src/librustc_metadata/creader.rs b/src/librustc_metadata/creader.rs
index fcdb968dc06..e1255110a83 100644
--- a/src/librustc_metadata/creader.rs
+++ b/src/librustc_metadata/creader.rs
@@ -1058,7 +1058,7 @@ impl<'a> middle::cstore::CrateLoader for CrateLoader<'a> {
         self.inject_allocator_crate();
         self.inject_panic_runtime(krate);
 
-        if log_enabled!(log::INFO) {
+        if log_enabled!(log::LogLevel::Info) {
             dump_crates(&self.cstore);
         }
 
diff --git a/src/librustc_mir/Cargo.toml b/src/librustc_mir/Cargo.toml
index 531be0b6ae9..6e42e02d510 100644
--- a/src/librustc_mir/Cargo.toml
+++ b/src/librustc_mir/Cargo.toml
@@ -10,7 +10,7 @@ crate-type = ["dylib"]
 
 [dependencies]
 graphviz = { path = "../libgraphviz" }
-log = { path = "../liblog" }
+log = "0.3"
 rustc = { path = "../librustc" }
 rustc_const_eval = { path = "../librustc_const_eval" }
 rustc_const_math = { path = "../librustc_const_math" }
diff --git a/src/librustc_passes/Cargo.toml b/src/librustc_passes/Cargo.toml
index cc710e0ac35..d2560c2f820 100644
--- a/src/librustc_passes/Cargo.toml
+++ b/src/librustc_passes/Cargo.toml
@@ -9,10 +9,10 @@ path = "lib.rs"
 crate-type = ["dylib"]
 
 [dependencies]
-log = { path = "../liblog" }
+log = "0.3"
 rustc = { path = "../librustc" }
 rustc_const_eval = { path = "../librustc_const_eval" }
 rustc_const_math = { path = "../librustc_const_math" }
 syntax = { path = "../libsyntax" }
 syntax_pos = { path = "../libsyntax_pos" }
-rustc_errors = { path = "../librustc_errors" }
\ No newline at end of file
+rustc_errors = { path = "../librustc_errors" }
diff --git a/src/librustc_resolve/Cargo.toml b/src/librustc_resolve/Cargo.toml
index 5ce4c74e735..0968ea31b75 100644
--- a/src/librustc_resolve/Cargo.toml
+++ b/src/librustc_resolve/Cargo.toml
@@ -10,7 +10,7 @@ crate-type = ["dylib"]
 test = false
 
 [dependencies]
-log = { path = "../liblog" }
+log = "0.3"
 syntax = { path = "../libsyntax" }
 rustc = { path = "../librustc" }
 arena = { path = "../libarena" }
diff --git a/src/librustc_save_analysis/Cargo.toml b/src/librustc_save_analysis/Cargo.toml
index 06c5150fd13..07a5c266fc0 100644
--- a/src/librustc_save_analysis/Cargo.toml
+++ b/src/librustc_save_analysis/Cargo.toml
@@ -9,7 +9,7 @@ path = "lib.rs"
 crate-type = ["dylib"]
 
 [dependencies]
-log = { path = "../liblog" }
+log = "0.3"
 rustc = { path = "../librustc" }
 syntax = { path = "../libsyntax" }
 syntax_pos = { path = "../libsyntax_pos" }
diff --git a/src/librustc_trans/Cargo.toml b/src/librustc_trans/Cargo.toml
index b5c67ad998b..07dcb2fc29d 100644
--- a/src/librustc_trans/Cargo.toml
+++ b/src/librustc_trans/Cargo.toml
@@ -11,7 +11,7 @@ test = false
 
 [dependencies]
 flate = { path = "../libflate" }
-log = { path = "../liblog" }
+log = "0.3"
 rustc = { path = "../librustc" }
 rustc_back = { path = "../librustc_back" }
 rustc_bitflags = { path = "../librustc_bitflags" }
diff --git a/src/librustc_typeck/Cargo.toml b/src/librustc_typeck/Cargo.toml
index f08d26373e5..07998aa4a30 100644
--- a/src/librustc_typeck/Cargo.toml
+++ b/src/librustc_typeck/Cargo.toml
@@ -10,7 +10,7 @@ crate-type = ["dylib"]
 test = false
 
 [dependencies]
-log = { path = "../liblog" }
+log = "0.3"
 syntax = { path = "../libsyntax" }
 arena = { path = "../libarena" }
 fmt_macros = { path = "../libfmt_macros" }
diff --git a/src/librustdoc/Cargo.toml b/src/librustdoc/Cargo.toml
index 93c0bd6d6d8..1c479ce1d01 100644
--- a/src/librustdoc/Cargo.toml
+++ b/src/librustdoc/Cargo.toml
@@ -11,11 +11,13 @@ crate-type = ["dylib"]
 
 [dependencies]
 arena = { path = "../libarena" }
+env_logger = { version = "0.4", default-features = false }
+log = "0.3"
 rustc = { path = "../librustc" }
 rustc_back = { path = "../librustc_back" }
 rustc_const_eval = { path = "../librustc_const_eval" }
-rustc_driver = { path = "../librustc_driver" }
 rustc_data_structures = { path = "../librustc_data_structures" }
+rustc_driver = { path = "../librustc_driver" }
 rustc_errors = { path = "../librustc_errors" }
 rustc_lint = { path = "../librustc_lint" }
 rustc_metadata = { path = "../librustc_metadata" }
@@ -24,7 +26,6 @@ rustc_trans = { path = "../librustc_trans" }
 serialize = { path = "../libserialize" }
 syntax = { path = "../libsyntax" }
 syntax_pos = { path = "../libsyntax_pos" }
-log = { path = "../liblog" }
 
 [build-dependencies]
 build_helper = { path = "../build_helper" }
diff --git a/src/librustdoc/lib.rs b/src/librustdoc/lib.rs
index 84f69cd3504..8dd03f6edc4 100644
--- a/src/librustdoc/lib.rs
+++ b/src/librustdoc/lib.rs
@@ -30,6 +30,7 @@
 
 extern crate arena;
 extern crate getopts;
+extern crate env_logger;
 extern crate libc;
 extern crate rustc;
 extern crate rustc_const_eval;
@@ -99,6 +100,7 @@ struct Output {
 
 pub fn main() {
     const STACK_SIZE: usize = 32_000_000; // 32MB
+    env_logger::init().unwrap();
     let res = std::thread::Builder::new().stack_size(STACK_SIZE).spawn(move || {
         let s = env::args().collect::<Vec<_>>();
         main_args(&s)
diff --git a/src/libsyntax/Cargo.toml b/src/libsyntax/Cargo.toml
index 0b38f5450b6..97d37266130 100644
--- a/src/libsyntax/Cargo.toml
+++ b/src/libsyntax/Cargo.toml
@@ -10,7 +10,7 @@ crate-type = ["dylib"]
 
 [dependencies]
 serialize = { path = "../libserialize" }
-log = { path = "../liblog" }
+log = "0.3"
 rustc_bitflags = { path = "../librustc_bitflags" }
 syntax_pos = { path = "../libsyntax_pos" }
 rustc_errors = { path = "../librustc_errors" }
diff --git a/src/libsyntax_ext/Cargo.toml b/src/libsyntax_ext/Cargo.toml
index 960db792a62..bdcec26cb83 100644
--- a/src/libsyntax_ext/Cargo.toml
+++ b/src/libsyntax_ext/Cargo.toml
@@ -10,7 +10,7 @@ crate-type = ["dylib"]
 
 [dependencies]
 fmt_macros = { path = "../libfmt_macros" }
-log = { path = "../liblog" }
+log = "0.3"
 proc_macro = { path = "../libproc_macro" }
 rustc_errors = { path = "../librustc_errors" }
 syntax = { path = "../libsyntax" }
diff --git a/src/test/run-pass-fulldeps/auxiliary/logging_right_crate.rs b/src/test/run-pass-fulldeps/auxiliary/logging_right_crate.rs
deleted file mode 100644
index db26b10fc67..00000000000
--- a/src/test/run-pass-fulldeps/auxiliary/logging_right_crate.rs
+++ /dev/null
@@ -1,18 +0,0 @@
-// Copyright 2013-2014 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-#![feature(rustc_private)]
-
-#[macro_use] extern crate log;
-
-pub fn foo<T>() {
-    fn death() -> isize { panic!() }
-    debug!("{}", (||{ death() })());
-}
diff --git a/src/test/run-pass-fulldeps/conditional-debug-macro-off.rs b/src/test/run-pass-fulldeps/conditional-debug-macro-off.rs
deleted file mode 100644
index c6beb5ba358..00000000000
--- a/src/test/run-pass-fulldeps/conditional-debug-macro-off.rs
+++ /dev/null
@@ -1,23 +0,0 @@
-// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-// compile-flags: -C debug-assertions=no
-// exec-env:RUST_LOG=conditional-debug-macro-off=4
-
-
-#![feature(rustc_private)]
-
-#[macro_use]
-extern crate log;
-
-pub fn main() {
-    // only panics if println! evaluates its argument.
-    debug!("{:?}", { if true { panic!() } });
-}
diff --git a/src/test/run-pass-fulldeps/logging-enabled-debug.rs b/src/test/run-pass-fulldeps/logging-enabled-debug.rs
deleted file mode 100644
index 3ae4884ce47..00000000000
--- a/src/test/run-pass-fulldeps/logging-enabled-debug.rs
+++ /dev/null
@@ -1,24 +0,0 @@
-// Copyright 2013-2014 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-// compile-flags:-C debug-assertions=no
-// exec-env:RUST_LOG=logging-enabled-debug=debug
-
-
-#![feature(rustc_private)]
-
-#[macro_use]
-extern crate log;
-
-pub fn main() {
-    if log_enabled!(log::DEBUG) {
-        panic!("what?! debugging?");
-    }
-}
diff --git a/src/test/run-pass-fulldeps/logging-enabled.rs b/src/test/run-pass-fulldeps/logging-enabled.rs
deleted file mode 100644
index 26261348020..00000000000
--- a/src/test/run-pass-fulldeps/logging-enabled.rs
+++ /dev/null
@@ -1,27 +0,0 @@
-// Copyright 2013-2014 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-// exec-env:RUST_LOG=logging_enabled=info
-// ignore-emscripten: FIXME(#31622)
-
-
-#![feature(rustc_private)]
-
-#[macro_use]
-extern crate log;
-
-pub fn main() {
-    if log_enabled!(log::DEBUG) {
-        panic!("what?! debugging?");
-    }
-    if !log_enabled!(log::INFO) {
-        panic!("what?! no info?");
-    }
-}
diff --git a/src/test/run-pass-fulldeps/logging-right-crate.rs b/src/test/run-pass-fulldeps/logging-right-crate.rs
deleted file mode 100644
index 7caeeb40124..00000000000
--- a/src/test/run-pass-fulldeps/logging-right-crate.rs
+++ /dev/null
@@ -1,31 +0,0 @@
-// Copyright 2013-2014 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-// aux-build:logging_right_crate.rs
-// exec-env:RUST_LOG=logging-right-crate=debug
-
-// This is a test for issue #3046 to make sure that when we monomorphize a
-// function from one crate to another the right top-level logging name is
-// preserved.
-//
-// It used to be the case that if logging were turned on for this crate, all
-// monomorphized functions from other crates had logging turned on (their
-// logging module names were all incorrect). This test ensures that this no
-// longer happens by enabling logging for *this* crate and then invoking a
-// function in an external crate which will panic when logging is enabled.
-
-// pretty-expanded FIXME #23616
-
-extern crate logging_right_crate;
-
-pub fn main() {
-    // this function panicks if logging is turned on
-    logging_right_crate::foo::<isize>();
-}
diff --git a/src/test/run-pass-fulldeps/logging-separate-lines.rs b/src/test/run-pass-fulldeps/logging-separate-lines.rs
deleted file mode 100644
index 183a522bba7..00000000000
--- a/src/test/run-pass-fulldeps/logging-separate-lines.rs
+++ /dev/null
@@ -1,40 +0,0 @@
-// Copyright 2013-2014 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-// ignore-windows
-// exec-env:RUST_LOG=debug
-// compile-flags:-C debug-assertions=y
-// ignore-emscripten: FIXME(#31622)
-
-#![feature(rustc_private)]
-
-#[macro_use]
-extern crate log;
-
-use std::process::Command;
-use std::env;
-use std::str;
-
-fn main() {
-    let args: Vec<String> = env::args().collect();
-    if args.len() > 1 && args[1] == "child" {
-        debug!("foo");
-        debug!("bar");
-        return
-    }
-
-    let p = Command::new(&args[0])
-                    .arg("child")
-                    .output().unwrap();
-    assert!(p.status.success());
-    let mut lines = str::from_utf8(&p.stderr).unwrap().lines();
-    assert!(lines.next().unwrap().contains("foo"));
-    assert!(lines.next().unwrap().contains("bar"));
-}
diff --git a/src/test/run-pass-fulldeps/rust-log-filter.rs b/src/test/run-pass-fulldeps/rust-log-filter.rs
deleted file mode 100644
index 306d24e3177..00000000000
--- a/src/test/run-pass-fulldeps/rust-log-filter.rs
+++ /dev/null
@@ -1,58 +0,0 @@
-// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-// exec-env:RUST_LOG=rust_log_filter/foo
-// ignore-emscripten no threads support
-
-#![allow(unknown_features)]
-#![feature(box_syntax, std_misc, rustc_private)]
-
-#[macro_use]
-extern crate log;
-
-use std::sync::mpsc::{channel, Sender, Receiver};
-use std::thread;
-
-pub struct ChannelLogger {
-    tx: Sender<String>
-}
-
-impl ChannelLogger {
-    pub fn new() -> (Box<ChannelLogger>, Receiver<String>) {
-        let (tx, rx) = channel();
-        (box ChannelLogger { tx: tx }, rx)
-    }
-}
-
-impl log::Logger for ChannelLogger {
-    fn log(&mut self, record: &log::LogRecord) {
-        self.tx.send(format!("{}", record.args)).unwrap();
-    }
-}
-
-pub fn main() {
-    let (logger, rx) = ChannelLogger::new();
-
-    let t = thread::spawn(move|| {
-        log::set_logger(logger);
-
-        info!("foo");
-        info!("bar");
-        info!("foo bar");
-        info!("bar foo");
-    });
-
-    assert_eq!(rx.recv().unwrap(), "foo");
-    assert_eq!(rx.recv().unwrap(), "foo bar");
-    assert_eq!(rx.recv().unwrap(), "bar foo");
-    assert!(rx.recv().is_err());
-
-    t.join();
-}
diff --git a/src/test/run-pass/conditional-debug-macro-on.rs b/src/test/run-pass/conditional-debug-macro-on.rs
index b335e20f91d..7da33be7a57 100644
--- a/src/test/run-pass/conditional-debug-macro-on.rs
+++ b/src/test/run-pass/conditional-debug-macro-on.rs
@@ -8,8 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// exec-env:RUST_LOG=conditional-debug-macro-on=4
-
 pub fn main() {
     // exits early if println! evaluates its arguments, otherwise it
     // will hit the panic.
diff --git a/src/tools/compiletest/Cargo.toml b/src/tools/compiletest/Cargo.toml
index 1fc98a78a7c..7530b65a9b7 100644
--- a/src/tools/compiletest/Cargo.toml
+++ b/src/tools/compiletest/Cargo.toml
@@ -5,6 +5,6 @@ version = "0.0.0"
 
 [dependencies]
 log = "0.3"
-env_logger = { version = "0.3.5", default-features = false }
+env_logger = { version = "0.4", default-features = false }
 rustc-serialize = "0.3"
 filetime = "0.1"