Auto merge of #115627 - compiler-errors:icedump-no-std, r=m-ou-se

Don't modify libstd to dump rustc ICEs

Do a much simpler thing and just dump a `std::backtrace::Backtrace` to file.

r? `@estebank` `@oli-obk`

Fixes #115610

compiler/rustc_driver_impl/src/lib.rs

@@ -7,7 +7,7 @@
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(lazy_cell)]
 #![feature(decl_macro)]
-#![feature(ice_to_disk)]
+#![feature(panic_update_hook)]
 #![feature(let_chains)]
 #![recursion_limit = "256"]
 #![allow(rustc::potential_query_instability)]
@@ -50,9 +50,9 @@ use std::collections::BTreeMap;
 use std::env;
 use std::ffi::OsString;
 use std::fmt::Write as _;
-use std::fs;
+use std::fs::{self, File};
 use std::io::{self, IsTerminal, Read, Write};
-use std::panic::{self, catch_unwind};
+use std::panic::{self, catch_unwind, PanicInfo};
 use std::path::PathBuf;
 use std::process::{self, Command, Stdio};
 use std::str;
@@ -1326,31 +1326,59 @@ pub fn install_ice_hook(bug_report_url: &'static str, extra_info: fn(&Handler))
         std::env::set_var("RUST_BACKTRACE", "full");
     }
 
-    panic::set_hook(Box::new(move |info| {
+    panic::update_hook(Box::new(
-        // If the error was caused by a broken pipe then this is not a bug.
+        move |default_hook: &(dyn Fn(&PanicInfo<'_>) + Send + Sync + 'static),
-        // Write the error and return immediately. See #98700.
+              info: &PanicInfo<'_>| {
-        #[cfg(windows)]
+            // If the error was caused by a broken pipe then this is not a bug.
-        if let Some(msg) = info.payload().downcast_ref::<String>() {
+            // Write the error and return immediately. See #98700.
-            if msg.starts_with("failed printing to stdout: ") && msg.ends_with("(os error 232)") {
+            #[cfg(windows)]
-                // the error code is already going to be reported when the panic unwinds up the stack
+            if let Some(msg) = info.payload().downcast_ref::<String>() {
-                let handler = EarlyErrorHandler::new(ErrorOutputType::default());
+                if msg.starts_with("failed printing to stdout: ") && msg.ends_with("(os error 232)")
-                let _ = handler.early_error_no_abort(msg.clone());
+                {
-                return;
+                    // the error code is already going to be reported when the panic unwinds up the stack
+                    let handler = EarlyErrorHandler::new(ErrorOutputType::default());
+                    let _ = handler.early_error_no_abort(msg.clone());
+                    return;
+                }
+            };
+
+            // Invoke the default handler, which prints the actual panic message and optionally a backtrace
+            // Don't do this for delayed bugs, which already emit their own more useful backtrace.
+            if !info.payload().is::<rustc_errors::DelayedBugPanic>() {
+                default_hook(info);
+                // Separate the output with an empty line
+                eprintln!();
+
+                if let Some(ice_path) = ice_path()
+                    && let Ok(mut out) =
+                        File::options().create(true).append(true).open(&ice_path)
+                {
+                    // The current implementation always returns `Some`.
+                    let location = info.location().unwrap();
+                    let msg = match info.payload().downcast_ref::<&'static str>() {
+                        Some(s) => *s,
+                        None => match info.payload().downcast_ref::<String>() {
+                            Some(s) => &s[..],
+                            None => "Box<dyn Any>",
+                        },
+                    };
+                    let thread = std::thread::current();
+                    let name = thread.name().unwrap_or("<unnamed>");
+                    let _ = write!(
+                        &mut out,
+                        "thread '{name}' panicked at {location}:\n\
+                        {msg}\n\
+                        stack backtrace:\n\
+                        {:#}",
+                        std::backtrace::Backtrace::force_capture()
+                    );
+                }
             }
-        };
 
-        // Invoke the default handler, which prints the actual panic message and optionally a backtrace
+            // Print the ICE message
-        // Don't do this for delayed bugs, which already emit their own more useful backtrace.
+            report_ice(info, bug_report_url, extra_info);
-        if !info.payload().is::<rustc_errors::DelayedBugPanic>() {
+        },
-            std::panic_hook_with_disk_dump(info, ice_path().as_deref());
+    ));
-
-            // Separate the output with an empty line
-            eprintln!();
-        }
-
-        // Print the ICE message
-        report_ice(info, bug_report_url, extra_info);
-    }));
 }
 
 /// Prints the ICE message, including query stack, but without backtrace.

library/std/src/lib.rs

@@ -637,9 +637,6 @@ pub mod alloc;
 // Private support modules
 mod panicking;
 
-#[unstable(feature = "ice_to_disk", issue = "none")]
-pub use panicking::panic_hook_with_disk_dump;
-
 #[path = "../../backtrace/src/lib.rs"]
 #[allow(dead_code, unused_attributes, fuzzy_provenance_casts)]
 mod backtrace_rs;

library/std/src/panicking.rs

@@ -236,14 +236,6 @@ where
 
 /// The default panic handler.
 fn default_hook(info: &PanicInfo<'_>) {
-    panic_hook_with_disk_dump(info, None)
-}
-
-#[unstable(feature = "ice_to_disk", issue = "none")]
-/// The implementation of the default panic handler.
-///
-/// It can also write the backtrace to a given `path`. This functionality is used only by `rustc`.
-pub fn panic_hook_with_disk_dump(info: &PanicInfo<'_>, path: Option<&crate::path::Path>) {
     // If this is a double panic, make sure that we print a backtrace
     // for this panic. Otherwise only print it if logging is enabled.
     let backtrace = if info.force_no_backtrace() {
@@ -267,7 +259,7 @@ pub fn panic_hook_with_disk_dump(info: &PanicInfo<'_>, path: Option<&crate::path
     let thread = thread_info::current_thread();
     let name = thread.as_ref().and_then(|t| t.name()).unwrap_or("<unnamed>");
 
-    let write = |err: &mut dyn crate::io::Write, backtrace: Option<BacktraceStyle>| {
+    let write = |err: &mut dyn crate::io::Write| {
         let _ = writeln!(err, "thread '{name}' panicked at {location}:\n{msg}");
 
         static FIRST_PANIC: AtomicBool = AtomicBool::new(true);
@@ -281,19 +273,11 @@ pub fn panic_hook_with_disk_dump(info: &PanicInfo<'_>, path: Option<&crate::path
             }
             Some(BacktraceStyle::Off) => {
                 if FIRST_PANIC.swap(false, Ordering::SeqCst) {
-                    if let Some(path) = path {
+                    let _ = writeln!(
-                        let _ = writeln!(
+                        err,
-                            err,
+                        "note: run with `RUST_BACKTRACE=1` environment variable to display a \
-                            "note: a backtrace for this error was stored at `{}`",
-                            path.display(),
-                        );
-                    } else {
-                        let _ = writeln!(
-                            err,
-                            "note: run with `RUST_BACKTRACE=1` environment variable to display a \
                              backtrace"
-                        );
+                    );
-                    }
                 }
             }
             // If backtraces aren't supported or are forced-off, do nothing.
@@ -301,17 +285,11 @@ pub fn panic_hook_with_disk_dump(info: &PanicInfo<'_>, path: Option<&crate::path
         }
     };
 
-    if let Some(path) = path
-        && let Ok(mut out) = crate::fs::File::options().create(true).append(true).open(&path)
-    {
-        write(&mut out, BacktraceStyle::full());
-    }
-
     if let Some(local) = set_output_capture(None) {
-        write(&mut *local.lock().unwrap_or_else(|e| e.into_inner()), backtrace);
+        write(&mut *local.lock().unwrap_or_else(|e| e.into_inner()));
         set_output_capture(Some(local));
     } else if let Some(mut out) = panic_output() {
-        write(&mut out, backtrace);
+        write(&mut out);
     }
 }
 

tests/run-make/dump-ice-to-disk/check.sh

@@ -22,8 +22,8 @@ rm $TMPDIR/rustc-ice-*.txt
 # Explicitly disabling ICE dump
 export RUSTC_ICE=0
 $RUSTC src/lib.rs -Z treat-err-as-bug=1 1>$TMPDIR/rust-test-disabled.log 2>&1
-should_be_empty_tmp=$(ls -l $TMPDIR/rustc-ice-*.txt | wc -l)
+should_be_empty_tmp=$(ls -l $TMPDIR/rustc-ice-*.txt 2>/dev/null | wc -l)
-should_be_empty_dot=$(ls -l ./rustc-ice-*.txt | wc -l)
+should_be_empty_dot=$(ls -l ./rustc-ice-*.txt 2>/dev/null | wc -l)
 
 echo "#### ICE Dump content:"
 echo $content