Build with panic=unwind

Author: bjorn3

Cargo.toml

@@ -43,10 +43,10 @@ smallvec = "1.8.1"
 
 [features]
 # Enable features not ready to be enabled when compiling as part of rustc
-unstable-features = ["jit", "inline_asm_sym"]
+unstable-features = ["jit", "inline_asm_sym", "unwinding"]
 jit = ["cranelift-jit", "libloading"]
 inline_asm_sym = []
-unwinding = [] # Not yet included in unstable-features for performance reasons
+unwinding = []
 
 [package.metadata.rust-analyzer]
 rustc_private = true

build_system/build_sysroot.rs

@@ -206,7 +206,7 @@ fn build_clif_sysroot_for_triple(
     }
 
     // Build sysroot
-    let mut rustflags = vec!["-Zforce-unstable-if-unmarked".to_owned(), "-Cpanic=abort".to_owned()];
+    let mut rustflags = vec!["-Zforce-unstable-if-unmarked".to_owned()];
     match cg_clif_dylib_path {
         CodegenBackend::Local(path) => {
             rustflags.push(format!("-Zcodegen-backend={}", path.to_str().unwrap()));

build_system/tests.rs

@@ -404,7 +404,6 @@ impl<'a> TestRunner<'a> {
         cmd.arg("-Cdebuginfo=2");
         cmd.arg("--target");
         cmd.arg(&self.target_compiler.triple);
-        cmd.arg("-Cpanic=abort");
         cmd.arg("--check-cfg=cfg(jit)");
         cmd.args(args);
         cmd

example/std_example.rs

@@ -16,7 +16,12 @@ use std::io::Write;
 use std::ops::Coroutine;
 
 fn main() {
-    println!("{:?}", std::env::args().collect::<Vec<_>>());
+    println!(
+        "{:?}",
+        std::panic::catch_unwind(|| {
+            panic!("foo");
+        })
+    );
 
     let mutex = std::sync::Mutex::new(());
     let _guard = mutex.lock().unwrap();

patches/0028-stdlib-Avoid-compiling-panic_abort.patch

@@ -0,0 +1,25 @@
+From 43c0b573c426ed7945bc25586c494f86b4d93c86 Mon Sep 17 00:00:00 2001
+From: bjorn3 <[email protected]>
+Date: Wed, 16 Apr 2025 11:52:26 +0000
+Subject: [PATCH] Avoid compiling panic_abort
+
+It requires -Cpanic=abort, but cargo doesn't allow setting that for a single crate
+---
+ library/std/Cargo.toml | 1 -
+ 1 file changed, 1 deletion(-)
+
+diff --git a/library/std/Cargo.toml b/library/std/Cargo.toml
+index 176da60..fd90469 100644
+--- a/library/std/Cargo.toml
++++ b/library/std/Cargo.toml
+@@ -16,7 +16,6 @@ crate-type = ["dylib", "rlib"]
+ alloc = { path = "../alloc", public = true }
+ cfg-if = { version = "1.0", features = ['rustc-dep-of-std'] }
+ panic_unwind = { path = "../panic_unwind", optional = true }
+-panic_abort = { path = "../panic_abort" }
+ core = { path = "../core", public = true }
+ compiler_builtins = { path = "../compiler-builtins/compiler-builtins" }
+ unwind = { path = "../unwind" }
+-- 
+2.43.0
+

scripts/cargo-clif.rs

@@ -12,7 +12,7 @@ fn main() {
         sysroot = sysroot.parent().unwrap();
     }
 
-    let mut rustflags = vec!["-Cpanic=abort".to_owned(), "-Zpanic-abort-tests".to_owned()];
+    let mut rustflags = vec![];
     if let Some(name) = option_env!("BUILTIN_BACKEND") {
         rustflags.push(format!("-Zcodegen-backend={name}"));
     } else {

scripts/rustc-clif.rs

@@ -17,8 +17,6 @@ fn main() {
 
     let passed_args = std::env::args_os().skip(1).collect::<Vec<_>>();
     let mut args = vec![];
-    args.push(OsString::from("-Cpanic=abort"));
-    args.push(OsString::from("-Zpanic-abort-tests"));
     if let Some(name) = option_env!("BUILTIN_BACKEND") {
         args.push(OsString::from(format!("-Zcodegen-backend={name}")))
     } else {

scripts/rustdoc-clif.rs

@@ -17,8 +17,6 @@ fn main() {
 
     let passed_args = std::env::args_os().skip(1).collect::<Vec<_>>();
     let mut args = vec![];
-    args.push(OsString::from("-Cpanic=abort"));
-    args.push(OsString::from("-Zpanic-abort-tests"));
     if let Some(name) = option_env!("BUILTIN_BACKEND") {
         args.push(OsString::from(format!("-Zcodegen-backend={name}")))
     } else {