fix(bootstrap): set rpath for rustc-main tests

Signed-off-by: HNO3Miracle <xiangao.or@isrc.iscas.ac.cn>

Author: HNO3Miracle

src/bootstrap/src/bin/rustc.rs

@@ -22,8 +22,8 @@ use std::time::Instant;
 
 use arg_file_command::ArgFileCommand;
 use shared_helpers::{
-    dylib_path, dylib_path_var, exe, maybe_dump, parse_rustc_stage, parse_rustc_verbose,
-    parse_value_from_args,
+    dylib_path, dylib_path_var, exe, maybe_dump, parse_extern_path_from_args, parse_rustc_stage,
+    parse_rustc_verbose, parse_value_from_args,
 };
 
 #[path = "../utils/shared_helpers.rs"]
@@ -252,6 +252,19 @@ fn main() {
     }
 
     let is_test = args.iter().any(|a| a == "--test");
+    if is_test
+        && crate_name == Some("rustc_main")
+        && target == Some(host.as_str())
+        && supports_absolute_rpath(&host)
+        && let Some(rustc_driver) = parse_extern_path_from_args(&orig_args, "rustc_driver")
+        && let Some(rustc_driver_dir) = Path::new(rustc_driver).parent()
+    {
+        // This is a temporary test binary under Cargo's build directory, not the
+        // staged rustc binary. Its runtime rpath needs to point to the actual
+        // rustc_driver dylib that Cargo linked it against.
+        cmd.arg(format!("-Clink-arg=-Wl,-rpath,{}", rustc_driver_dir.display()));
+    }
+
     if verbose > 2 {
         let rust_env_vars =
             env::vars().filter(|(k, _)| k.starts_with("RUST") || k.starts_with("CARGO"));
@@ -332,6 +345,14 @@ fn main() {
     }
 }
 
+fn supports_absolute_rpath(target: &str) -> bool {
+    !target.contains("windows")
+        && !target.contains("cygwin")
+        && !target.contains("apple")
+        && !target.contains("aix")
+        && !target.contains("xous")
+}
+
 #[cfg(all(not(unix), not(windows)))]
 // In the future we can add this for more platforms
 fn format_rusage_data(_child: Child) -> Option<String> {

src/bootstrap/src/utils/shared_helpers.rs

@@ -126,3 +126,25 @@ pub fn parse_value_from_args<'a>(args: &'a [OsString], key: &str) -> Option<&'a
 
     None
 }
+
+/// Finds an `--extern crate=path` argument and returns its path.
+pub fn parse_extern_path_from_args<'a>(args: &'a [OsString], krate: &str) -> Option<&'a str> {
+    let krate = format!("{krate}=");
+    let mut args = args.iter();
+    while let Some(arg) = args.next() {
+        let arg = arg.to_str().unwrap();
+        let value = if let Some(value) = arg.strip_prefix("--extern=") {
+            value
+        } else if arg == "--extern" {
+            args.next()?.to_str().unwrap()
+        } else {
+            continue;
+        };
+
+        if let Some(path) = value.strip_prefix(&krate) {
+            return Some(path);
+        }
+    }
+
+    None
+}

src/bootstrap/src/utils/tests/shared_helpers_tests.rs

@@ -5,7 +5,7 @@
 //! To prevent tidy from complaining about this file not being named `tests.rs`, it lives inside a
 //! submodule directory named `tests`.
 
-use crate::utils::shared_helpers::parse_value_from_args;
+use crate::utils::shared_helpers::{parse_extern_path_from_args, parse_value_from_args};
 
 #[test]
 fn test_parse_value_from_args() {
@@ -33,3 +33,22 @@ fn test_parse_value_from_args() {
     assert_eq!(parse_value_from_args(args.as_slice(), "--key").unwrap(), "value");
     assert_eq!(parse_value_from_args(args.as_slice(), "--sysroot").unwrap(), "/x/y/z");
 }
+
+#[test]
+fn test_parse_extern_path_from_args() {
+    let args = vec![
+        "--extern".into(),
+        "rustc_driver=/path/to/librustc_driver.so".into(),
+        "--extern=rustc_ast=/path/to/librustc_ast.rlib".into(),
+    ];
+
+    assert_eq!(
+        parse_extern_path_from_args(args.as_slice(), "rustc_driver").unwrap(),
+        "/path/to/librustc_driver.so"
+    );
+    assert_eq!(
+        parse_extern_path_from_args(args.as_slice(), "rustc_ast").unwrap(),
+        "/path/to/librustc_ast.rlib"
+    );
+    assert!(parse_extern_path_from_args(args.as_slice(), "rustc_middle").is_none());
+}