Fix nix patching for LLVM 18

LLVM 18 now ships `libLLVM*.so.*`, so `.so` is not the sole extension
anymore, which breaks the dylib detection. Oops! Adjust it to only
search for `.so` somewhere.

Author: Noratrieb

src/bootstrap/bootstrap.py

@@ -612,8 +612,14 @@ def download_toolchain(self):
                 self.fix_bin_or_dylib("{}/libexec/rust-analyzer-proc-macro-srv".format(bin_root))
                 lib_dir = "{}/lib".format(bin_root)
                 for lib in os.listdir(lib_dir):
-                    if lib.endswith(".so"):
-                        self.fix_bin_or_dylib(os.path.join(lib_dir, lib))
+                    # .so is not necessarily the suffix, there can be version numbers afterwards.
+                    if ".so" in lib:
+                        elf_path = os.path.join(lib_dir, lib)
+                        with open(elf_path, "rb") as f:
+                            magic = f.read(4)
+                            # Patchelf will skip non-ELF files, but issue a warning.
+                            if magic == b"\x7fELF":
+                                self.fix_bin_or_dylib(elf_path)
 
             with output(self.rustc_stamp()) as rust_stamp:
                 rust_stamp.write(key)
@@ -725,7 +731,7 @@ def fix_bin_or_dylib(self, fname):
             os.path.join(os.path.realpath(nix_deps_dir), "lib")
         ]
         patchelf_args = ["--set-rpath", ":".join(rpath_entries)]
-        if not fname.endswith(".so"):
+        if ".so" not in fname:
             # Finally, set the correct .interp for binaries
             with open("{}/nix-support/dynamic-linker".format(nix_deps_dir)) as dynamic_linker:
                 patchelf_args += ["--set-interpreter", dynamic_linker.read().rstrip()]

src/bootstrap/src/core/download.rs

@@ -1,6 +1,6 @@
 use std::{
     env,
-    ffi::{OsStr, OsString},
+    ffi::OsString,
     fs::{self, File},
     io::{BufRead, BufReader, BufWriter, ErrorKind, Write},
     path::{Path, PathBuf},
@@ -183,7 +183,7 @@ impl Config {
             entries
         };
         patchelf.args(&[OsString::from("--set-rpath"), rpath_entries]);
-        if !fname.extension().map_or(false, |ext| ext == "so") {
+        if !path_is_dylib(fname) {
             // Finally, set the correct .interp for binaries
             let dynamic_linker_path = nix_deps_dir.join("nix-support/dynamic-linker");
             // FIXME: can we support utf8 here? `args` doesn't accept Vec<u8>, only OsString ...
@@ -440,7 +440,7 @@ impl Config {
             let lib_dir = bin_root.join("lib");
             for lib in t!(fs::read_dir(&lib_dir), lib_dir.display().to_string()) {
                 let lib = t!(lib);
-                if lib.path().extension() == Some(OsStr::new("so")) {
+                if path_is_dylib(&lib.path()) {
                     self.fix_bin_or_dylib(&lib.path());
                 }
             }
@@ -545,7 +545,7 @@ impl Config {
                 let lib_dir = bin_root.join("lib");
                 for lib in t!(fs::read_dir(&lib_dir), lib_dir.display().to_string()) {
                     let lib = t!(lib);
-                    if lib.path().extension() == Some(OsStr::new("so")) {
+                    if path_is_dylib(&lib.path()) {
                         self.fix_bin_or_dylib(&lib.path());
                     }
                 }
@@ -697,7 +697,7 @@ download-rustc = false
                 let llvm_lib = llvm_root.join("lib");
                 for entry in t!(fs::read_dir(llvm_lib)) {
                     let lib = t!(entry).path();
-                    if lib.extension().map_or(false, |ext| ext == "so") {
+                    if path_is_dylib(&lib) {
                         self.fix_bin_or_dylib(&lib);
                     }
                 }
@@ -743,3 +743,8 @@ download-rustc = false
         self.unpack(&tarball, &llvm_root, "rust-dev");
     }
 }
+
+fn path_is_dylib(path: &Path) -> bool {
+    // The .so is not necessarily the extension, it might be libLLVM.so.18.1
+    path.to_str().map_or(false, |path| path.contains(".so"))
+}