Auto merge of #108714 - estebank:ice_dump, r=oli-obk

On nightly, dump ICE backtraces to disk

Implement rust-lang/compiler-team#578.

When an ICE is encountered on nightly releases, the new rustc panic handler will also write the contents of the backtrace to disk. If any `delay_span_bug`s are encountered, their backtrace is also added to the file. The platform and rustc version will also be collected.

<img width="1032" alt="Screenshot 2023-03-03 at 2 13 25 PM" src="https://user-images.githubusercontent.com/1606434/222842420-8e039740-4042-4563-b31d-599677171acf.png">

The current behavior will *always* write to disk on nightly builds, regardless of whether the backtrace is printed to the terminal, unless the environment variable `RUSTC_ICE_DISK_DUMP` is set to `0`. This is a compromise and can be changed.

2 files changed, 15 insertions, 4 deletions

diff --git a/compiler/rustc_session/src/parse.rs b/compiler/rustc_session/src/parse.rs
index d5326df9ad9..b0a67c564ce 100644
--- a/compiler/rustc_session/src/parse.rs
+++ b/compiler/rustc_session/src/parse.rs
@@ -231,6 +231,7 @@ impl ParseSess {
             Some(sm.clone()),
             None,
             fallback_bundle,
+            None,
         );
         ParseSess::with_span_handler(handler, sm)
     }
@@ -261,12 +262,20 @@ impl ParseSess {
     pub fn with_silent_emitter(fatal_note: Option<String>) -> Self {
         let fallback_bundle = fallback_fluent_bundle(Vec::new(), false);
         let sm = Lrc::new(SourceMap::new(FilePathMapping::empty()));
-        let fatal_handler =
-            Handler::with_tty_emitter(ColorConfig::Auto, false, None, None, None, fallback_bundle);
+        let fatal_handler = Handler::with_tty_emitter(
+            ColorConfig::Auto,
+            false,
+            None,
+            None,
+            None,
+            fallback_bundle,
+            None,
+        );
         let handler = Handler::with_emitter(
             false,
             None,
             Box::new(SilentEmitter { fatal_handler, fatal_note }),
+            None,
         );
         ParseSess::with_span_handler(handler, sm)
     }
diff --git a/compiler/rustc_session/src/session.rs b/compiler/rustc_session/src/session.rs
index c65d933bd6d..0f5d3b291db 100644
--- a/compiler/rustc_session/src/session.rs
+++ b/compiler/rustc_session/src/session.rs
@@ -1392,6 +1392,7 @@ pub fn build_session(
     file_loader: Option<Box<dyn FileLoader + Send + Sync + 'static>>,
     target_override: Option<Target>,
     cfg_version: &'static str,
+    ice_file: Option<PathBuf>,
 ) -> Session {
     // FIXME: This is not general enough to make the warning lint completely override
     // normal diagnostic warnings, since the warning lint can also be denied and changed
@@ -1440,6 +1441,7 @@ pub fn build_session(
     let span_diagnostic = rustc_errors::Handler::with_emitter_and_flags(
         emitter,
         sopts.unstable_opts.diagnostic_handler_flags(can_emit_warnings),
+        ice_file,
     );
 
     let self_profiler = if let SwitchWithOptPath::Enabled(ref d) = sopts.unstable_opts.self_profile
@@ -1731,7 +1733,7 @@ pub struct EarlyErrorHandler {
 impl EarlyErrorHandler {
     pub fn new(output: ErrorOutputType) -> Self {
         let emitter = mk_emitter(output);
-        Self { handler: rustc_errors::Handler::with_emitter(true, None, emitter) }
+        Self { handler: rustc_errors::Handler::with_emitter(true, None, emitter, None) }
     }
 
     pub fn abort_if_errors(&self) {
@@ -1745,7 +1747,7 @@ impl EarlyErrorHandler {
         self.handler.abort_if_errors();
 
         let emitter = mk_emitter(output);
-        self.handler = Handler::with_emitter(true, None, emitter);
+        self.handler = Handler::with_emitter(true, None, emitter, None);
     }
 
     #[allow(rustc::untranslatable_diagnostic)]