[EXPERIMENTAL] bootstrap: add structured tracing to ./x test tests/ui and ./x build compiler/rustc_codegen_gcc flows

Example usages:

```bash
$ BOOTSTRAP_LOG=bootstrap=TRACE,STEPS_TO_RUN=TRACE ./x build ./compiler/rustc_codegen_gcc/ --stage 1
$ BOOTSTRAP_LOG=bootstrap=TRACE ./x build ./compiler/rustc_codegen_gcc/ --stage 1
$ BOOTSTRAP_LOG=bootstrap=TRACE ./x test tests/ui --stage 1
$ BOOTSTRAP_LOG=bootstrap=TRACE ./x test tests/ui src/tools/run-make-support --stage 1
```

Author: jieyouxu

src/bootstrap/Cargo.lock

@@ -58,6 +58,9 @@ dependencies = [
  "tar",
  "termcolor",
  "toml",
+ "tracing",
+ "tracing-subscriber",
+ "tracing-tree",
  "walkdir",
  "windows 0.52.0",
  "xz2",
@@ -70,7 +73,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "40723b8fb387abc38f4f4a37c09073622e41dd12327033091ef8950659e6dc0c"
 dependencies = [
  "memchr",
- "regex-automata",
+ "regex-automata 0.4.9",
  "serde",
 ]
 
@@ -271,8 +274,8 @@ dependencies = [
  "aho-corasick",
  "bstr",
  "log",
- "regex-automata",
- "regex-syntax",
+ "regex-automata 0.4.9",
+ "regex-syntax 0.8.5",
 ]
 
 [[package]]
@@ -300,7 +303,7 @@ dependencies = [
  "globset",
  "log",
  "memchr",
- "regex-automata",
+ "regex-automata 0.4.9",
  "same-file",
  "walkdir",
  "winapi-util",
@@ -322,6 +325,12 @@ dependencies = [
  "windows-sys 0.52.0",
 ]
 
+[[package]]
+name = "lazy_static"
+version = "1.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bbd2bcb4c963f2ddae06a2efc7e9f3591312473c50c6685e1f298068316e66fe"
+
 [[package]]
 name = "libc"
 version = "0.2.167"
@@ -362,6 +371,15 @@ dependencies = [
  "pkg-config",
 ]
 
+[[package]]
+name = "matchers"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8263075bb86c5a1b1427b5ae862e8889656f126e9f77c484496e8b47cf5c5558"
+dependencies = [
+ "regex-automata 0.1.10",
+]
+
 [[package]]
 name = "memchr"
 version = "2.7.4"
@@ -377,6 +395,25 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "nu-ansi-term"
+version = "0.46.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "77a8165726e8236064dbb45459242600304b42a5ea24ee2948e18e023bf7ba84"
+dependencies = [
+ "overload",
+ "winapi",
+]
+
+[[package]]
+name = "nu-ansi-term"
+version = "0.50.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d4a28e057d01f97e61255210fcff094d74ed0466038633e95017f5beb68e4399"
+dependencies = [
+ "windows-sys 0.52.0",
+]
+
 [[package]]
 name = "object"
 version = "0.36.5"
@@ -386,6 +423,12 @@ dependencies = [
  "memchr",
 ]
 
+[[package]]
+name = "once_cell"
+version = "1.20.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1261fe7e33c73b354eab43b1273a57c8f967d0391e80353e51f764ac02cf6775"
+
 [[package]]
 name = "opener"
 version = "0.5.2"
@@ -396,6 +439,18 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "overload"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b15813163c1d831bf4a13c3610c05c0d03b39feb07f7e09fa234dac9b15aaf39"
+
+[[package]]
+name = "pin-project-lite"
+version = "0.2.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3b3cff922bd51709b605d9ead9aa71031d81447142d828eb4a6eba76fe619f9b"
+
 [[package]]
 name = "pkg-config"
 version = "0.3.31"
@@ -439,6 +494,27 @@ dependencies = [
  "bitflags",
 ]
 
+[[package]]
+name = "regex"
+version = "1.11.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b544ef1b4eac5dc2db33ea63606ae9ffcfac26c1416a2806ae0bf5f56b201191"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-automata 0.4.9",
+ "regex-syntax 0.8.5",
+]
+
+[[package]]
+name = "regex-automata"
+version = "0.1.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6c230d73fb8d8c1b9c0b3135c5142a8acee3a0558fb8db5cf1cb65f8d7862132"
+dependencies = [
+ "regex-syntax 0.6.29",
+]
+
 [[package]]
 name = "regex-automata"
 version = "0.4.9"
@@ -447,9 +523,15 @@ checksum = "809e8dc61f6de73b46c85f4c96486310fe304c434cfa43669d7b40f711150908"
 dependencies = [
  "aho-corasick",
  "memchr",
- "regex-syntax",
+ "regex-syntax 0.8.5",
 ]
 
+[[package]]
+name = "regex-syntax"
+version = "0.6.29"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f162c6dd7b008981e4d40210aca20b4bd0f9b60ca9271061b07f78537722f2e1"
+
 [[package]]
 name = "regex-syntax"
 version = "0.8.5"
@@ -539,12 +621,27 @@ dependencies = [
  "digest",
 ]
 
+[[package]]
+name = "sharded-slab"
+version = "0.1.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f40ca3c46823713e0d4209592e8d6e826aa57e928f09752619fc696c499637f6"
+dependencies = [
+ "lazy_static",
+]
+
 [[package]]
 name = "shlex"
 version = "1.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0fda2ff0d084019ba4d7c6f371c95d8fd75ce3524c3cb8fb653a3023f6323e64"
 
+[[package]]
+name = "smallvec"
+version = "1.13.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3c5e1a9a646d36c3599cd173a41282daf47c44583ad367b8e6837255952e5c67"
+
 [[package]]
 name = "syn"
 version = "2.0.87"
@@ -589,6 +686,16 @@ dependencies = [
  "winapi-util",
 ]
 
+[[package]]
+name = "thread_local"
+version = "1.1.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8b9ef9bad013ada3808854ceac7b46812a6465ba368859a37e2100283d2d719c"
+dependencies = [
+ "cfg-if",
+ "once_cell",
+]
+
 [[package]]
 name = "toml"
 version = "0.5.11"
@@ -598,6 +705,79 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "tracing"
+version = "0.1.41"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "784e0ac535deb450455cbfa28a6f0df145ea1bb7ae51b821cf5e7927fdcfbdd0"
+dependencies = [
+ "pin-project-lite",
+ "tracing-attributes",
+ "tracing-core",
+]
+
+[[package]]
+name = "tracing-attributes"
+version = "0.1.28"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "395ae124c09f9e6918a2310af6038fba074bcf474ac352496d5910dd59a2226d"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "tracing-core"
+version = "0.1.33"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e672c95779cf947c5311f83787af4fa8fffd12fb27e4993211a84bdfd9610f9c"
+dependencies = [
+ "once_cell",
+ "valuable",
+]
+
+[[package]]
+name = "tracing-log"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ee855f1f400bd0e5c02d150ae5de3840039a3f54b025156404e34c23c03f47c3"
+dependencies = [
+ "log",
+ "once_cell",
+ "tracing-core",
+]
+
+[[package]]
+name = "tracing-subscriber"
+version = "0.3.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e8189decb5ac0fa7bc8b96b7cb9b2701d60d48805aca84a238004d665fcc4008"
+dependencies = [
+ "matchers",
+ "nu-ansi-term 0.46.0",
+ "once_cell",
+ "regex",
+ "sharded-slab",
+ "smallvec",
+ "thread_local",
+ "tracing",
+ "tracing-core",
+ "tracing-log",
+]
+
+[[package]]
+name = "tracing-tree"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f459ca79f1b0d5f71c54ddfde6debfc59c8b6eeb46808ae492077f739dc7b49c"
+dependencies = [
+ "nu-ansi-term 0.50.1",
+ "tracing-core",
+ "tracing-log",
+ "tracing-subscriber",
+]
+
 [[package]]
 name = "typenum"
 version = "1.17.0"
@@ -610,6 +790,12 @@ version = "1.0.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e91b56cd4cadaeb79bbf1a5645f6b4f8dc5bde8834ad5894a8db35fda9efa1fe"
 
+[[package]]
+name = "valuable"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "830b7e5d4d90034032940e4ace0d9a9a057e7a45cd94e6c007832e39edb82f6d"
+
 [[package]]
 name = "version_check"
 version = "0.9.5"

src/bootstrap/Cargo.toml

@@ -40,7 +40,7 @@ cc = "=1.2.0"
 cmake = "=0.1.48"
 
 build_helper = { path = "../build_helper" }
-clap = { version = "4.4", default-features = false, features = ["std", "usage", "help", "derive", "error-context"] }
+clap = { version = "4.4", default-features = false, features = ["derive", "error-context", "help", "std", "usage"] }
 clap_complete = "4.4"
 fd-lock = "4.0"
 home = "0.5"
@@ -61,6 +61,10 @@ toml = "0.5"
 walkdir = "2.4"
 xz2 = "0.1"
 
+tracing = { version = "0.1.41", features = ["attributes"] }
+tracing-subscriber = { version = "0.3.19", features = ["env-filter", "fmt", "registry", "std"] }
+tracing-tree = "0.4.0"
+
 # Dependencies needed by the build-metrics feature
 sysinfo = { version = "0.33.0", default-features = false, optional = true, features = ["system"] }
 

src/bootstrap/src/bin/main.rs

@@ -15,24 +15,46 @@ use bootstrap::{
     human_readable_changes, t,
 };
 use build_helper::ci::CiEnv;
+use tracing::*;
+use tracing_subscriber::EnvFilter;
+use tracing_subscriber::prelude::*;
+
+fn setup_logging() {
+    let filter = EnvFilter::from_env("BOOTSTRAP_LOG");
+    let layer = tracing_tree::HierarchicalLayer::default()
+        .with_writer(std::io::stderr)
+        .with_ansi(true)
+        .with_targets(true)
+        .with_bracketed_fields(true)
+        .with_indent_amount(2)
+        .with_indent_lines(true);
+    let subscriber = tracing_subscriber::registry().with(filter).with(layer);
+
+    tracing::subscriber::set_global_default(subscriber).unwrap();
+}
 
+#[instrument(level = "trace", name = "main")]
 fn main() {
+    setup_logging();
     let args = env::args().skip(1).collect::<Vec<_>>();
+    trace!(?args, "main binary invoked");
 
     if Flags::try_parse_verbose_help(&args) {
         return;
     }
 
     let flags = Flags::parse(&args);
+    trace!("parsed `Flags`");
     let config = Config::parse(flags);
+    trace!("parsed `Config`");
 
     let mut build_lock;
     let _build_lock_guard;
 
     if !config.bypass_bootstrap_lock {
-        // Display PID of process holding the lock
-        // PID will be stored in a lock file
+        // Display PID of process holding the lock. PID will be stored in a lock file.
         let lock_path = config.out.join("lock");
+        trace!(lock_path = ?lock_path.display(), "establishing bootstrap lock");
         let pid = fs::read_to_string(&lock_path);
 
         build_lock = fd_lock::RwLock::new(t!(fs::OpenOptions::new()