4 files changed, 37 insertions, 29 deletions
diff --git a/src/bootstrap/bin/rustc.rs b/src/bootstrap/bin/rustc.rs
index 76d0e6e28ae..4607ca5cf9f 100644
--- a/src/bootstrap/bin/rustc.rs
+++ b/src/bootstrap/bin/rustc.rs
@@ -297,7 +297,12 @@ fn main() {
     }
 
     if verbose > 1 {
-        eprintln!("rustc command: {:?}", cmd);
+        eprintln!(
+            "rustc command: {:?}={:?} {:?}",
+            bootstrap::util::dylib_path_var(),
+            env::join_paths(&dylib_path).unwrap(),
+            cmd,
+        );
         eprintln!("sysroot: {:?}", sysroot);
         eprintln!("libdir: {:?}", libdir);
     }
diff --git a/src/bootstrap/builder.rs b/src/bootstrap/builder.rs
index 8a17a8b091b..cd646b76e83 100644
--- a/src/bootstrap/builder.rs
+++ b/src/bootstrap/builder.rs
@@ -1460,6 +1460,7 @@ mod __test {
             rustc_args: vec![],
             fail_fast: true,
             doc_tests: DocTests::No,
+            bless: false,
         };
 
         let build = Build::new(config);
diff --git a/src/bootstrap/flags.rs b/src/bootstrap/flags.rs
index 5315a3028ff..90dd5d819b0 100644
--- a/src/bootstrap/flags.rs
+++ b/src/bootstrap/flags.rs
@@ -59,6 +59,8 @@ pub enum Subcommand {
     },
     Test {
         paths: Vec<PathBuf>,
+        /// Whether to automatically update stderr/stdout files
+        bless: bool,
         test_args: Vec<String>,
         rustc_args: Vec<String>,
         fail_fast: bool,
@@ -173,6 +175,7 @@ To learn more about a subcommand, run `./x.py <subcommand> -h`");
                 );
                 opts.optflag("", "no-doc", "do not run doc tests");
                 opts.optflag("", "doc", "only run doc tests");
+                opts.optflag("", "bless", "update all stderr/stdout files of failing ui tests");
             },
             "bench" => { opts.optmulti("", "test-args", "extra arguments", "ARGS"); },
             "clean" => { opts.optflag("", "all", "clean all build artifacts"); },
@@ -258,6 +261,7 @@ Arguments:
         ./x.py test src/test/run-pass
         ./x.py test src/libstd --test-args hash_map
         ./x.py test src/libstd --stage 0
+        ./x.py test src/test/ui --bless
 
     If no arguments are passed then the complete artifacts for that stage are
     compiled and tested.
@@ -322,6 +326,7 @@ Arguments:
             "test" => {
                 Subcommand::Test {
                     paths,
+                    bless: matches.opt_present("bless"),
                     test_args: matches.opt_strs("test-args"),
                     rustc_args: matches.opt_strs("rustc-args"),
                     fail_fast: !matches.opt_present("no-fail-fast"),
@@ -424,6 +429,13 @@ impl Subcommand {
             _ => DocTests::Yes,
         }
     }
+
+    pub fn bless(&self) -> bool {
+        match *self {
+            Subcommand::Test { bless, .. } => bless,
+            _ => false,
+        }
+    }
 }
 
 fn split(s: Vec<String>) -> Vec<String> {
diff --git a/src/bootstrap/test.rs b/src/bootstrap/test.rs
index 1f81a617237..7a4924f03c8 100644
--- a/src/bootstrap/test.rs
+++ b/src/bootstrap/test.rs
@@ -47,6 +47,16 @@ pub enum TestKind {
     Bench,
 }
 
+impl From<Kind> for TestKind {
+    fn from(kind: Kind) -> Self {
+        match kind {
+            Kind::Test => TestKind::Test,
+            Kind::Bench => TestKind::Bench,
+            _ => panic!("unexpected kind in crate: {:?}", kind)
+        }
+    }
+}
+
 impl TestKind {
     // Return the cargo subcommand for this test kind
     fn subcommand(self) -> &'static str {
@@ -951,6 +961,10 @@ impl Step for Compiletest {
         cmd.arg("--host").arg(&*compiler.host);
         cmd.arg("--llvm-filecheck").arg(builder.llvm_filecheck(builder.config.build));
 
+        if builder.config.cmd.bless() {
+            cmd.arg("--bless");
+        }
+
         if let Some(ref nodejs) = builder.config.nodejs {
             cmd.arg("--nodejs").arg(nodejs);
         }
@@ -1342,13 +1356,7 @@ impl Step for CrateLibrustc {
 
         for krate in builder.in_tree_crates("rustc-main") {
             if run.path.ends_with(&krate.path) {
-                let test_kind = if builder.kind == Kind::Test {
-                    TestKind::Test
-                } else if builder.kind == Kind::Bench {
-                    TestKind::Bench
-                } else {
-                    panic!("unexpected builder.kind in crate: {:?}", builder.kind);
-                };
+                let test_kind = builder.kind.into();
 
                 builder.ensure(CrateLibrustc {
                     compiler,
@@ -1394,13 +1402,7 @@ impl Step for CrateNotDefault {
         let builder = run.builder;
         let compiler = builder.compiler(builder.top_stage, run.host);
 
-        let test_kind = if builder.kind == Kind::Test {
-            TestKind::Test
-        } else if builder.kind == Kind::Bench {
-            TestKind::Bench
-        } else {
-            panic!("unexpected builder.kind in crate: {:?}", builder.kind);
-        };
+        let test_kind = builder.kind.into();
 
         builder.ensure(CrateNotDefault {
             compiler,
@@ -1461,13 +1463,7 @@ impl Step for Crate {
         let compiler = builder.compiler(builder.top_stage, run.host);
 
         let make = |mode: Mode, krate: &CargoCrate| {
-            let test_kind = if builder.kind == Kind::Test {
-                TestKind::Test
-            } else if builder.kind == Kind::Bench {
-                TestKind::Bench
-            } else {
-                panic!("unexpected builder.kind in crate: {:?}", builder.kind);
-            };
+            let test_kind = builder.kind.into();
 
             builder.ensure(Crate {
                 compiler,
@@ -1625,13 +1621,7 @@ impl Step for CrateRustdoc {
     fn make_run(run: RunConfig) {
         let builder = run.builder;
 
-        let test_kind = if builder.kind == Kind::Test {
-            TestKind::Test
-        } else if builder.kind == Kind::Bench {
-            TestKind::Bench
-        } else {
-            panic!("unexpected builder.kind in crate: {:?}", builder.kind);
-        };
+        let test_kind = builder.kind.into();
 
         builder.ensure(CrateRustdoc {
             host: run.host,