From 84896c7f096c38d43e020612e639e5975aee7f34 Mon Sep 17 00:00:00 2001
From: Ximin Luo <infinity0@pwned.gg>
Date: Mon, 27 Jul 2020 22:06:04 +0100
Subject: [PATCH 1/3] rustbuild: use Display for exit status instead of Debug,
 see #74832 for justification

---
 src/bootstrap/bin/rustc.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/bootstrap/bin/rustc.rs b/src/bootstrap/bin/rustc.rs
index af75faf698e..9bb6dbc448d 100644
--- a/src/bootstrap/bin/rustc.rs
+++ b/src/bootstrap/bin/rustc.rs
@@ -152,7 +152,7 @@ fn main() {
             Ok(s) if s.success() => std::process::exit(0),
             e => e,
         };
-        println!("\nDid not run successfully: {:?}\n{:?}\n-------------", e, cmd);
+        println!("\nDid not run successfully: {}\n{:?}\n-------------", e, cmd);
         status_code(&mut on_fail).expect("could not run the backup command");
         std::process::exit(1);
     }

From 3dcab2922c4eaaea11a6856fa566bdb7a6d9c1f6 Mon Sep 17 00:00:00 2001
From: Ximin Luo <infinity0@pwned.gg>
Date: Mon, 27 Jul 2020 22:44:48 +0100
Subject: [PATCH 2/3] rustbuild: format both Ok/Err separately, since Result
 doesn't do it

---
 src/bootstrap/bin/rustc.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/bootstrap/bin/rustc.rs b/src/bootstrap/bin/rustc.rs
index 9bb6dbc448d..f0cb7be9691 100644
--- a/src/bootstrap/bin/rustc.rs
+++ b/src/bootstrap/bin/rustc.rs
@@ -149,8 +149,8 @@ fn main() {
 
     if let Some(mut on_fail) = on_fail {
         let e = match cmd.status() {
-            Ok(s) if s.success() => std::process::exit(0),
-            e => e,
+            Ok(s) => if s.success() { std::process::exit(0) } else { format!("Ok({})", s) },
+            Err(e) => format!("Err({})", e),
         };
         println!("\nDid not run successfully: {}\n{:?}\n-------------", e, cmd);
         status_code(&mut on_fail).expect("could not run the backup command");

From e7089a97e79fb550dcd76da47c614b2701963327 Mon Sep 17 00:00:00 2001
From: Ximin Luo <infinity0@pwned.gg>
Date: Mon, 27 Jul 2020 23:22:07 +0100
Subject: [PATCH 3/3] rustbuild: refactor how the wrapper deals with exit codes

---
 src/bootstrap/bin/rustc.rs | 50 ++++++++++++++++++--------------------
 1 file changed, 24 insertions(+), 26 deletions(-)

diff --git a/src/bootstrap/bin/rustc.rs b/src/bootstrap/bin/rustc.rs
index f0cb7be9691..d6649d0521c 100644
--- a/src/bootstrap/bin/rustc.rs
+++ b/src/bootstrap/bin/rustc.rs
@@ -16,7 +16,6 @@
 //! never get replaced.
 
 use std::env;
-use std::io;
 use std::path::PathBuf;
 use std::process::Command;
 use std::str::FromStr;
@@ -147,22 +146,15 @@ fn main() {
         eprintln!("libdir: {:?}", libdir);
     }
 
-    if let Some(mut on_fail) = on_fail {
-        let e = match cmd.status() {
-            Ok(s) => if s.success() { std::process::exit(0) } else { format!("Ok({})", s) },
-            Err(e) => format!("Err({})", e),
-        };
-        println!("\nDid not run successfully: {}\n{:?}\n-------------", e, cmd);
-        status_code(&mut on_fail).expect("could not run the backup command");
-        std::process::exit(1);
-    }
+    let start = Instant::now();
+    let status = {
+        let errmsg = format!("\nFailed to run:\n{:?}\n-------------", cmd);
+        cmd.status().expect(&errmsg)
+    };
 
     if env::var_os("RUSTC_PRINT_STEP_TIMINGS").is_some() {
         if let Some(crate_name) = crate_name {
-            let start = Instant::now();
-            let status = cmd.status().unwrap_or_else(|_| panic!("\n\n failed to run {:?}", cmd));
             let dur = start.elapsed();
-
             let is_test = args.iter().any(|a| a == "--test");
             eprintln!(
                 "[RUSTC-TIMING] {} test:{} {}.{:03}",
@@ -171,21 +163,27 @@ fn main() {
                 dur.as_secs(),
                 dur.subsec_millis()
             );
-
-            match status.code() {
-                Some(i) => std::process::exit(i),
-                None => {
-                    eprintln!("rustc exited with {}", status);
-                    std::process::exit(0xfe);
-                }
-            }
         }
     }
 
-    let code = status_code(&mut cmd).unwrap_or_else(|_| panic!("\n\n failed to run {:?}", cmd));
-    std::process::exit(code);
-}
+    if status.success() {
+        std::process::exit(0);
+        // note: everything below here is unreachable. do not put code that
+        // should run on success, after this block.
+    }
+    println!("\nDid not run successfully: {}\n{:?}\n-------------", status, cmd);
 
-fn status_code(cmd: &mut Command) -> io::Result<i32> {
-    cmd.status().map(|status| status.code().unwrap())
+    if let Some(mut on_fail) = on_fail {
+        on_fail.status().expect("Could not run the on_fail command");
+    }
+
+    // Preserve the exit code. In case of signal, exit with 0xfe since it's
+    // awkward to preserve this status in a cross-platform way.
+    match status.code() {
+        Some(i) => std::process::exit(i),
+        None => {
+            eprintln!("rustc exited with {}", status);
+            std::process::exit(0xfe);
+        }
+    }
 }