Add panic=immediate-abort support to Cargo

Author: saethlin

src/cargo/core/compiler/mod.rs

@@ -1305,7 +1305,7 @@ fn build_base_args(
         // flag to pass to rustc, so register that here. Eventually this flag
         // will simply not be needed when the behavior is stabilized in the Rust
         // compiler itself.
-        if *panic == PanicStrategy::Abort {
+        if *panic == PanicStrategy::Abort || *panic == PanicStrategy::ImmediateAbort {
             cmd.arg("-Z").arg("panic-abort-tests");
         }
     } else if test {

src/cargo/core/features.rs

@@ -579,6 +579,9 @@ features! {
 
     /// Allows use of multiple build scripts.
     (unstable, multiple_build_scripts, "", "reference/unstable.html#multiple-build-scripts"),
+
+    /// Allows use of panic="immediate-abort".
+    (unstable, panic_immediate_abort, "", "reference/unstable.html#panic-immediate-abort"),
 }
 
 /// Status and metadata for a single unstable feature.

src/cargo/core/profiles.rs

@@ -561,6 +561,7 @@ fn merge_profile(profile: &mut Profile, toml: &TomlProfile) {
         profile.panic = match panic.as_str() {
             "unwind" => PanicStrategy::Unwind,
             "abort" => PanicStrategy::Abort,
+            "immediate-abort" => PanicStrategy::ImmediateAbort,
             // This should be validated in TomlProfile::validate
             _ => panic!("Unexpected panic setting `{}`", panic),
         };
@@ -876,13 +877,15 @@ impl serde::ser::Serialize for Lto {
 pub enum PanicStrategy {
     Unwind,
     Abort,
+    ImmediateAbort,
 }
 
 impl fmt::Display for PanicStrategy {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match *self {
             PanicStrategy::Unwind => "unwind",
             PanicStrategy::Abort => "abort",
+            PanicStrategy::ImmediateAbort => "immediate-abort",
         }
         .fmt(f)
     }

src/doc/src/reference/unstable.md

@@ -95,6 +95,7 @@ Each new feature described below should explain how to use it.
     * [target-applies-to-host](#target-applies-to-host) --- Alters whether certain flags will be passed to host build targets.
     * [gc](#gc) --- Global cache garbage collection.
     * [open-namespaces](#open-namespaces) --- Allow multiple packages to participate in the same API namespace
+    * [panic-immediate-abort](#panic-immediate-abort) --- Passes `-Cpanic=immediate-abort` to the compiler.
 * rustdoc
     * [rustdoc-map](#rustdoc-map) --- Provides mappings for documentation to link to external sites like [docs.rs](https://docs.rs/).
     * [scrape-examples](#scrape-examples) --- Shows examples within documentation.
@@ -1670,6 +1671,23 @@ cargo-features = ["open-namespaces"]
 # ...
 ```
 
+## panic-immediate-abort
+
+* Tracking Issue: [#0000](https://github.com/rust-lang/cargo/issues/0000)
+
+Allow use of the ImmediateAbort panic strategy in a Cargo profile
+
+This can be enabled like so:
+```toml
+cargo-features = ["immediate-abort"]
+
+[package]
+# ...
+
+[profile.release]
+panic = "immediate-abort"
+```
+
 ## `[lints.cargo]`
 
 * Tracking Issue: [#12235](https://github.com/rust-lang/cargo/issues/12235)