Fix ICE on --print=... i/o errors

compiler/rustc_driver_impl/src/lib.rs

@@ -58,8 +58,16 @@ use std::str;
 use std::sync::LazyLock;
 use std::time::Instant;
 
+// This import blocks the use of panicking `print` and `println` in all the code
+// below. Please use `safe_print` and `safe_println` to avoid ICE when
+// encountering an I/O error during print.
+#[allow(unused_imports)]
+use std::{compile_error as print, compile_error as println};
+
 pub mod args;
 pub mod pretty;
+#[macro_use]
+mod print;
 mod session_diagnostics;
 
 use crate::session_diagnostics::{
@@ -511,7 +519,7 @@ fn handle_explain(registry: Registry, code: &str, output: ErrorOutputType) {
  if io::stdout().is_terminal() {
  show_content_with_pager(&text);
  } else {
- print!("{text}");
+ safe_print!("{text}");
  }
  }
  Err(InvalidErrorCode) => {
@@ -547,7 +555,7 @@ fn show_content_with_pager(content: &str) {
  // If pager fails for whatever reason, we should still print the content
  // to standard output
  if fallback_to_println {
- print!("{content}");
+ safe_print!("{content}");
  }
 }
 
@@ -601,7 +609,7 @@ pub fn list_metadata(sess: &Session, metadata_loader: &dyn MetadataLoader) -> Co
  let path = &(*ifile);
  let mut v = Vec::new();
  locator::list_file_metadata(&sess.target, path, metadata_loader, &mut v).unwrap();
- println!("{}", String::from_utf8(v).unwrap());
+ safe_println!("{}", String::from_utf8(v).unwrap());
  }
  Input::Str { .. } => {
  early_error(ErrorOutputType::default(), "cannot list metadata for stdin");
@@ -642,12 +650,12 @@ fn print_crate_info(
  TargetList => {
  let mut targets = rustc_target::spec::TARGETS.to_vec();
  targets.sort_unstable();
- println!("{}", targets.join("\n"));
+ safe_println!("{}", targets.join("\n"));
  }
- Sysroot => println!("{}", sess.sysroot.display()),
- TargetLibdir => println!("{}", sess.target_tlib_path.dir.display()),
+ Sysroot => safe_println!("{}", sess.sysroot.display()),
+ TargetLibdir => safe_println!("{}", sess.target_tlib_path.dir.display()),
  TargetSpec => {
- println!("{}", serde_json::to_string_pretty(&sess.target.to_json()).unwrap());
+ safe_println!("{}", serde_json::to_string_pretty(&sess.target.to_json()).unwrap());
  }
  AllTargetSpecs => {
  let mut targets = BTreeMap::new();
@@ -656,7 +664,7 @@ fn print_crate_info(
  let target = Target::expect_builtin(&triple);
  targets.insert(name, target.to_json());
  }
- println!("{}", serde_json::to_string_pretty(&targets).unwrap());
+ safe_println!("{}", serde_json::to_string_pretty(&targets).unwrap());
  }
  FileNames | CrateName => {
  let Some(attrs) = attrs.as_ref() else {
@@ -666,14 +674,14 @@ fn print_crate_info(
  let t_outputs = rustc_interface::util::build_output_filenames(attrs, sess);
  let id = rustc_session::output::find_crate_name(sess, attrs);
  if *req == PrintRequest::CrateName {
- println!("{id}");
+ safe_println!("{id}");
  continue;
  }
  let crate_types = collect_crate_types(sess, attrs);
  for &style in &crate_types {
  let fname =
  rustc_session::output::filename_for_input(sess, style, id, &t_outputs);
- println!("{}", fname.file_name().unwrap().to_string_lossy());
+ safe_println!("{}", fname.file_name().unwrap().to_string_lossy());
  }
  }
  Cfg => {
@@ -707,13 +715,13 @@ fn print_crate_info(
 
  cfgs.sort();
  for cfg in cfgs {
- println!("{cfg}");
+ safe_println!("{cfg}");
  }
  }
  CallingConventions => {
  let mut calling_conventions = rustc_target::spec::abi::all_names();
  calling_conventions.sort_unstable();
- println!("{}", calling_conventions.join("\n"));
+ safe_println!("{}", calling_conventions.join("\n"));
  }
  RelocationModels
  | CodeModels
@@ -733,7 +741,7 @@ fn print_crate_info(
  let stable = sess.target.options.supported_split_debuginfo.contains(split);
  let unstable_ok = sess.unstable_options();
  if stable || unstable_ok {
- println!("{split}");
+ safe_println!("{split}");
  }
  }
  }
@@ -770,14 +778,14 @@ pub fn version_at_macro_invocation(
 ) {
  let verbose = matches.opt_present("verbose");
 
- println!("{binary} {version}");
+ safe_println!("{binary} {version}");
 
  if verbose {
- println!("binary: {binary}");
- println!("commit-hash: {commit_hash}");
- println!("commit-date: {commit_date}");
- println!("host: {}", config::host_triple());
- println!("release: {release}");
+ safe_println!("binary: {binary}");
+ safe_println!("commit-hash: {commit_hash}");
+ safe_println!("commit-date: {commit_date}");
+ safe_println!("host: {}", config::host_triple());
+ safe_println!("release: {release}");
 
  let debug_flags = matches.opt_strs("Z");
  let backend_name = debug_flags.iter().find_map(|x| x.strip_prefix("codegen-backend="));
@@ -807,7 +815,7 @@ fn usage(verbose: bool, include_unstable_options: bool, nightly_build: bool) {
  } else {
  ""
  };
- println!(
+ safe_println!(
  "{options}{at_path}\nAdditional help:
  -C help Print codegen options
  -W help \
@@ -820,7 +828,7 @@ fn usage(verbose: bool, include_unstable_options: bool, nightly_build: bool) {
 }
 
 fn print_wall_help() {
- println!(
+ safe_println!(
  "
 The flag `-Wall` does not exist in `rustc`. Most useful lints are enabled by
 default. Use `rustc -W help` to see all available lints. It's more common to put
@@ -832,7 +840,7 @@ the command line flag directly.
 
 /// Write to stdout lint command options, together with a list of all available lints
 pub fn describe_lints(sess: &Session, lint_store: &LintStore, loaded_plugins: bool) {
- println!(
+ safe_println!(
  "
 Available lint options:
  -W <foo> Warn about <foo>
@@ -877,21 +885,21 @@ Available lint options:
  s
  };
 
- println!("Lint checks provided by rustc:\n");
+ safe_println!("Lint checks provided by rustc:\n");
 
  let print_lints = |lints: Vec<&Lint>| {
- println!(" {} {:7.7} {}", padded("name"), "default", "meaning");
- println!(" {} {:7.7} {}", padded("----"), "-------", "-------");
+ safe_println!(" {} {:7.7} {}", padded("name"), "default", "meaning");
+ safe_println!(" {} {:7.7} {}", padded("----"), "-------", "-------");
  for lint in lints {
  let name = lint.name_lower().replace('_', "-");
- println!(
+ safe_println!(
  " {} {:7.7} {}",
  padded(&name),
  lint.default_level(sess.edition()).as_str(),
  lint.desc
  );
  }
- println!("\n");
+ safe_println!("\n");
  };
 
  print_lints(builtin);
@@ -912,14 +920,14 @@ Available lint options:
  s
  };
 
- println!("Lint groups provided by rustc:\n");
+ safe_println!("Lint groups provided by rustc:\n");
 
  let print_lint_groups = |lints: Vec<(&'static str, Vec<LintId>)>, all_warnings| {
- println!(" {} sub-lints", padded("name"));
- println!(" {} ---------", padded("----"));
+ safe_println!(" {} sub-lints", padded("name"));
+ safe_println!(" {} ---------", padded("----"));
 
  if all_warnings {
- println!(" {} all lints that are set to issue warnings", padded("warnings"));
+ safe_println!(" {} all lints that are set to issue warnings", padded("warnings"));
  }
 
  for (name, to) in lints {
@@ -929,26 +937,26 @@ Available lint options:
  .map(|x| x.to_string().replace('_', "-"))
  .collect::<Vec<String>>()
  .join(", ");
- println!(" {} {}", padded(&name), desc);
+ safe_println!(" {} {}", padded(&name), desc);
  }
- println!("\n");
+ safe_println!("\n");
  };
 
  print_lint_groups(builtin_groups, true);
 
  match (loaded_plugins, plugin.len(), plugin_groups.len()) {
  (false, 0, _) | (false, _, 0) => {
- println!("Lint tools like Clippy can provide additional lints and lint groups.");
+ safe_println!("Lint tools like Clippy can provide additional lints and lint groups.");
  }
  (false, ..) => panic!("didn't load lint plugins but got them anyway!"),
- (true, 0, 0) => println!("This crate does not load any lint plugins or lint groups."),
+ (true, 0, 0) => safe_println!("This crate does not load any lint plugins or lint groups."),
  (true, l, g) => {
  if l > 0 {
- println!("Lint checks provided by plugins loaded by this crate:\n");
+ safe_println!("Lint checks provided by plugins loaded by this crate:\n");
  print_lints(plugin);
  }
  if g > 0 {
- println!("Lint groups provided by plugins loaded by this crate:\n");
+ safe_println!("Lint groups provided by plugins loaded by this crate:\n");
  print_lint_groups(plugin_groups, false);
  }
  }
@@ -996,12 +1004,12 @@ pub fn describe_flag_categories(matches: &Matches) -> bool {
 }
 
 fn describe_debug_flags() {
- println!("\nAvailable options:\n");
+ safe_println!("\nAvailable options:\n");
  print_flag_list("-Z", config::Z_OPTIONS);
 }
 
 fn describe_codegen_flags() {
- println!("\nAvailable codegen options:\n");
+ safe_println!("\nAvailable codegen options:\n");
  print_flag_list("-C", config::CG_OPTIONS);
 }
 
@@ -1012,7 +1020,7 @@ fn print_flag_list<T>(
  let max_len = flag_list.iter().map(|&(name, _, _, _)| name.chars().count()).max().unwrap_or(0);
 
  for &(name, _, _, desc) in flag_list {
- println!(
+ safe_println!(
  " {} {:>width$}=val -- {}",
  cmdline_opt,
  name.replace('_', "-"),

compiler/rustc_driver_impl/src/print.rs

@@ -0,0 +1,20 @@
+use std::fmt;
+use std::io::{self, Write as _};
+
+macro_rules! safe_print {
+ ($($arg:tt)*) => {{
+ $crate::print::print(std::format_args!($($arg)*));
+ }};
+}
+
+macro_rules! safe_println {
+ ($($arg:tt)*) => {
+ safe_print!("{}\n", std::format_args!($($arg)*))
+ };
+}
+
+pub(crate) fn print(args: fmt::Arguments<'_>) {
+ if let Err(_) = io::stdout().write_fmt(args) {
+ rustc_errors::FatalError.raise();
+ }
+}