Allow building stage1+ std with panic=abort

config.example.toml

@@ -504,6 +504,9 @@
 # Defaults to rust.overflow-checks value
 #overflow-checks-std = rust.overflow-checks (boolean)
 
+# The panic strategy used for all compiler invocations
+#panic-strategy = "unwind"
+
 # Debuginfo level for most of Rust code, corresponds to the `-C debuginfo=N` option of `rustc`.
 # `0` - no debug info
 # `1` - line tables only - sufficient to generate backtraces that include line

src/bootstrap/src/core/builder.rs

@@ -2135,6 +2135,10 @@ impl<'a> Builder<'a> {
             cargo.env("RUSTFLAGS", &rustc_args.join(" "));
         }
 
+        if matches!(self.config.rust_panic_strategy, crate::PanicStrategy::Abort) {
+            rustflags.arg("-Cpanic=abort");
+        }
+
         Cargo { command: cargo, rustflags, rustdocflags, hostflags, allow_features }
     }
 

src/bootstrap/src/core/config/config.rs

@@ -105,6 +105,14 @@ impl Display for DebuginfoLevel {
     }
 }
 
+#[derive(Clone, Copy, Debug, Default, PartialEq, Deserialize)]
+#[serde(rename_all = "lowercase")]
+pub enum PanicStrategy {
+    #[default]
+    Unwind,
+    Abort,
+}
+
 /// LLD in bootstrap works like this:
 /// - Self-contained lld: use `rust-lld` from the compiler's sysroot
 /// - External: use an external `lld` binary
@@ -272,6 +280,7 @@ pub struct Config {
     pub rust_profile_generate: Option<String>,
     pub rust_lto: RustcLto,
     pub rust_validate_mir_opts: Option<u32>,
+    pub rust_panic_strategy: PanicStrategy,
     pub llvm_profile_use: Option<String>,
     pub llvm_profile_generate: bool,
     pub llvm_libunwind_default: Option<LlvmLibunwind>,
@@ -1111,6 +1120,7 @@ define_config! {
         download_rustc: Option<StringOrBool> = "download-rustc",
         lto: Option<String> = "lto",
         validate_mir_opts: Option<u32> = "validate-mir-opts",
+        panic_strategy: Option<PanicStrategy> = "panic-strategy",
     }
 }
 
@@ -1562,6 +1572,7 @@ impl Config {
                 stack_protector,
                 strip,
                 lld_mode,
+                panic_strategy,
             } = rust;
 
             set(&mut config.channel, channel);
@@ -1594,6 +1605,7 @@ impl Config {
             debuginfo_level_std = debuginfo_level_std_toml;
             debuginfo_level_tools = debuginfo_level_tools_toml;
             debuginfo_level_tests = debuginfo_level_tests_toml;
+            set(&mut config.rust_panic_strategy, panic_strategy);
 
             config.rust_split_debuginfo = split_debuginfo
                 .as_deref()

src/bootstrap/src/lib.rs

@@ -16,6 +16,7 @@
 //! More documentation can be found in each respective module below, and you can
 //! also check out the `src/bootstrap/README.md` file for more information.
 
+use core::config::PanicStrategy;
 use std::cell::{Cell, RefCell};
 use std::collections::{HashMap, HashSet};
 use std::env;
@@ -708,13 +709,19 @@ impl Build {
     /// Gets the space-separated set of activated features for the standard
     /// library.
     fn std_features(&self, target: TargetSelection) -> String {
-        let mut features = " panic-unwind".to_string();
+        let mut features = match self.config.rust_panic_strategy {
+            PanicStrategy::Abort => String::new(),
+            _ => {
+                let mut features = " panic-unwind".to_string();
+                match self.config.llvm_libunwind(target) {
+                    LlvmLibunwind::InTree => features.push_str(" llvm-libunwind"),
+                    LlvmLibunwind::System => features.push_str(" system-llvm-libunwind"),
+                    LlvmLibunwind::No => {}
+                }
+                features
+            }
+        };
 
-        match self.config.llvm_libunwind(target) {
-            LlvmLibunwind::InTree => features.push_str(" llvm-libunwind"),
-            LlvmLibunwind::System => features.push_str(" system-llvm-libunwind"),
-            LlvmLibunwind::No => {}
-        }
         if self.config.backtrace {
             features.push_str(" backtrace");
         }