Rollup merge of #103660 - ozkanonur:master, r=jyn514

improve `filesearch::get_or_default_sysroot`

`fn get_or_default_sysroot` is now improved and used in `miri` and `clippy`, and tests are still passing as they should. So we no longer need to implement custom workarounds/hacks to find sysroot in tools like miri/clippy.

Resolves https://github.com/rust-lang/rust/issues/98832

re-opened from #103581

1 files changed, 2 insertions, 95 deletions

diff --git a/compiler/rustc_interface/src/util.rs b/compiler/rustc_interface/src/util.rs
index 519b8a7fc7c..62ee72f9883 100644
--- a/compiler/rustc_interface/src/util.rs
+++ b/compiler/rustc_interface/src/util.rs
@@ -9,6 +9,7 @@ use rustc_session as session;
 use rustc_session::config::CheckCfg;
 use rustc_session::config::{self, CrateType};
 use rustc_session::config::{ErrorOutputType, Input, OutputFilenames};
+use rustc_session::filesearch::sysroot_candidates;
 use rustc_session::lint::{self, BuiltinLintDiagnostics, LintBuffer};
 use rustc_session::parse::CrateConfig;
 use rustc_session::{early_error, filesearch, output, Session};
@@ -78,7 +79,7 @@ pub fn create_session(
 
     let bundle = match rustc_errors::fluent_bundle(
         sopts.maybe_sysroot.clone(),
-        sysroot_candidates(),
+        sysroot_candidates().to_vec(),
         sopts.unstable_opts.translate_lang.clone(),
         sopts.unstable_opts.translate_additional_ftl.as_deref(),
         sopts.unstable_opts.translate_directionality_markers,
@@ -273,100 +274,6 @@ fn get_rustc_path_inner(bin_path: &str) -> Option<PathBuf> {
     })
 }
 
-fn sysroot_candidates() -> Vec<PathBuf> {
-    let target = session::config::host_triple();
-    let mut sysroot_candidates = vec![filesearch::get_or_default_sysroot()];
-    let path = current_dll_path().and_then(|s| s.canonicalize().ok());
-    if let Some(dll) = path {
-        // use `parent` twice to chop off the file name and then also the
-        // directory containing the dll which should be either `lib` or `bin`.
-        if let Some(path) = dll.parent().and_then(|p| p.parent()) {
-            // The original `path` pointed at the `rustc_driver` crate's dll.
-            // Now that dll should only be in one of two locations. The first is
-            // in the compiler's libdir, for example `$sysroot/lib/*.dll`. The
-            // other is the target's libdir, for example
-            // `$sysroot/lib/rustlib/$target/lib/*.dll`.
-            //
-            // We don't know which, so let's assume that if our `path` above
-            // ends in `$target` we *could* be in the target libdir, and always
-            // assume that we may be in the main libdir.
-            sysroot_candidates.push(path.to_owned());
-
-            if path.ends_with(target) {
-                sysroot_candidates.extend(
-                    path.parent() // chop off `$target`
-                        .and_then(|p| p.parent()) // chop off `rustlib`
-                        .and_then(|p| p.parent()) // chop off `lib`
-                        .map(|s| s.to_owned()),
-                );
-            }
-        }
-    }
-
-    return sysroot_candidates;
-
-    #[cfg(unix)]
-    fn current_dll_path() -> Option<PathBuf> {
-        use std::ffi::{CStr, OsStr};
-        use std::os::unix::prelude::*;
-
-        unsafe {
-            let addr = current_dll_path as usize as *mut _;
-            let mut info = mem::zeroed();
-            if libc::dladdr(addr, &mut info) == 0 {
-                info!("dladdr failed");
-                return None;
-            }
-            if info.dli_fname.is_null() {
-                info!("dladdr returned null pointer");
-                return None;
-            }
-            let bytes = CStr::from_ptr(info.dli_fname).to_bytes();
-            let os = OsStr::from_bytes(bytes);
-            Some(PathBuf::from(os))
-        }
-    }
-
-    #[cfg(windows)]
-    fn current_dll_path() -> Option<PathBuf> {
-        use std::ffi::OsString;
-        use std::io;
-        use std::os::windows::prelude::*;
-        use std::ptr;
-
-        use winapi::um::libloaderapi::{
-            GetModuleFileNameW, GetModuleHandleExW, GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS,
-        };
-
-        unsafe {
-            let mut module = ptr::null_mut();
-            let r = GetModuleHandleExW(
-                GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS,
-                current_dll_path as usize as *mut _,
-                &mut module,
-            );
-            if r == 0 {
-                info!("GetModuleHandleExW failed: {}", io::Error::last_os_error());
-                return None;
-            }
-            let mut space = Vec::with_capacity(1024);
-            let r = GetModuleFileNameW(module, space.as_mut_ptr(), space.capacity() as u32);
-            if r == 0 {
-                info!("GetModuleFileNameW failed: {}", io::Error::last_os_error());
-                return None;
-            }
-            let r = r as usize;
-            if r >= space.capacity() {
-                info!("our buffer was too small? {}", io::Error::last_os_error());
-                return None;
-            }
-            space.set_len(r);
-            let os = OsString::from_wide(&space);
-            Some(PathBuf::from(os))
-        }
-    }
-}
-
 fn get_codegen_sysroot(maybe_sysroot: &Option<PathBuf>, backend_name: &str) -> MakeBackendFn {
     // For now we only allow this function to be called once as it'll dlopen a
     // few things, which seems to work best if we only do that once. In