summaryrefslogtreecommitdiffstats
path: root/compiler/rustc_log/src/lib.rs
diff options
context:
space:
mode:
authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-17 12:02:58 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-17 12:02:58 +0000
commit698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch)
tree173a775858bd501c378080a10dca74132f05bc50 /compiler/rustc_log/src/lib.rs
parentInitial commit. (diff)
downloadrustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz
rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'compiler/rustc_log/src/lib.rs')
-rw-r--r--compiler/rustc_log/src/lib.rs122
1 files changed, 122 insertions, 0 deletions
diff --git a/compiler/rustc_log/src/lib.rs b/compiler/rustc_log/src/lib.rs
new file mode 100644
index 000000000..f2ec80b0c
--- /dev/null
+++ b/compiler/rustc_log/src/lib.rs
@@ -0,0 +1,122 @@
+//! This crate allows tools to enable rust logging without having to magically
+//! match rustc's tracing crate version.
+//!
+//! For example if someone is working on rustc_ast and wants to write some
+//! minimal code against it to run in a debugger, with access to the `debug!`
+//! logs emitted by rustc_ast, that can be done by writing:
+//!
+//! ```toml
+//! [dependencies]
+//! rustc_ast = { path = "../rust/compiler/rustc_ast" }
+//! rustc_log = { path = "../rust/compiler/rustc_log" }
+//! rustc_span = { path = "../rust/compiler/rustc_span" }
+//! ```
+//!
+//! ```
+//! fn main() {
+//! rustc_log::init_rustc_env_logger().unwrap();
+//!
+//! let edition = rustc_span::edition::Edition::Edition2021;
+//! rustc_span::create_session_globals_then(edition, || {
+//! /* ... */
+//! });
+//! }
+//! ```
+//!
+//! Now `RUSTC_LOG=debug cargo run` will run your minimal main.rs and show
+//! rustc's debug logging. In a workflow like this, one might also add
+//! `std::env::set_var("RUSTC_LOG", "debug")` to the top of main so that `cargo
+//! run` by itself is sufficient to get logs.
+//!
+//! The reason rustc_log is a tiny separate crate, as opposed to exposing the
+//! same things in rustc_driver only, is to enable the above workflow. If you
+//! had to depend on rustc_driver in order to turn on rustc's debug logs, that's
+//! an enormously bigger dependency tree; every change you make to rustc_ast (or
+//! whichever piece of the compiler you are interested in) would involve
+//! rebuilding all the rest of rustc up to rustc_driver in order to run your
+//! main.rs. Whereas by depending only on rustc_log and the few crates you are
+//! debugging, you can make changes inside those crates and quickly run main.rs
+//! to read the debug logs.
+
+use std::env::{self, VarError};
+use std::fmt::{self, Display};
+use std::io;
+use tracing_subscriber::filter::{Directive, EnvFilter, LevelFilter};
+use tracing_subscriber::layer::SubscriberExt;
+
+pub fn init_rustc_env_logger() -> Result<(), Error> {
+ init_env_logger("RUSTC_LOG")
+}
+
+/// In contrast to `init_rustc_env_logger` this allows you to choose an env var
+/// other than `RUSTC_LOG`.
+pub fn init_env_logger(env: &str) -> Result<(), Error> {
+ let filter = match env::var(env) {
+ Ok(env) => EnvFilter::new(env),
+ _ => EnvFilter::default().add_directive(Directive::from(LevelFilter::WARN)),
+ };
+
+ let color_logs = match env::var(String::from(env) + "_COLOR") {
+ Ok(value) => match value.as_ref() {
+ "always" => true,
+ "never" => false,
+ "auto" => stderr_isatty(),
+ _ => return Err(Error::InvalidColorValue(value)),
+ },
+ Err(VarError::NotPresent) => stderr_isatty(),
+ Err(VarError::NotUnicode(_value)) => return Err(Error::NonUnicodeColorValue),
+ };
+
+ let verbose_entry_exit = match env::var_os(String::from(env) + "_ENTRY_EXIT") {
+ None => false,
+ Some(v) => &v != "0",
+ };
+
+ let layer = tracing_tree::HierarchicalLayer::default()
+ .with_writer(io::stderr)
+ .with_indent_lines(true)
+ .with_ansi(color_logs)
+ .with_targets(true)
+ .with_verbose_exit(verbose_entry_exit)
+ .with_verbose_entry(verbose_entry_exit)
+ .with_indent_amount(2);
+ #[cfg(parallel_compiler)]
+ let layer = layer.with_thread_ids(true).with_thread_names(true);
+
+ let subscriber = tracing_subscriber::Registry::default().with(filter).with(layer);
+ tracing::subscriber::set_global_default(subscriber).unwrap();
+
+ Ok(())
+}
+
+pub fn stdout_isatty() -> bool {
+ atty::is(atty::Stream::Stdout)
+}
+
+pub fn stderr_isatty() -> bool {
+ atty::is(atty::Stream::Stderr)
+}
+
+#[derive(Debug)]
+pub enum Error {
+ InvalidColorValue(String),
+ NonUnicodeColorValue,
+}
+
+impl std::error::Error for Error {}
+
+impl Display for Error {
+ fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
+ match self {
+ Error::InvalidColorValue(value) => write!(
+ formatter,
+ "invalid log color value '{}': expected one of always, never, or auto",
+ value,
+ ),
+ Error::NonUnicodeColorValue => write!(
+ formatter,
+ "non-Unicode log color value: expected one of always, never, or auto",
+ ),
+ }
+ }
+}