bjoernager/rust
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Unify dylib loading between proc macros and codegen backends

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As bonus this makes the errors when failing to load a proc macro more
informative to match the backend loading errors. In addition it makes it
slightly easier to patch rustc to work on platforms that don't support
dynamic linking like wasm.
This commit is contained in:
bjorn3 2024-02-21 11:17:07 +00:00
parent 0987e41d1c
commit f25c90a83f
9 changed files with 60 additions and 45 deletions
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1
compiler/rustc_interface/src/lib.rs
View file

@ -1,5 +1,4 @@
#![feature(decl_macro)]
#![feature(error_iter)]
#![feature(generic_nonzero)]
#![feature(lazy_cell)]
#![feature(let_chains)]

33
compiler/rustc_interface/src/util.rs
View file

@ -1,10 +1,10 @@
use crate::errors;
use info;
use libloading::Library;
use rustc_ast as ast;
use rustc_codegen_ssa::traits::CodegenBackend;
#[cfg(parallel_compiler)]
use rustc_data_structures::sync;
use rustc_metadata::{load_symbol_from_dylib, DylibError};
use rustc_parse::validate_attr;
use rustc_session as session;
use rustc_session::config::{self, Cfg, CrateType, OutFileName, OutputFilenames, OutputTypes};
@ -17,7 +17,6 @@ use rustc_span::symbol::{sym, Symbol};
use session::EarlyDiagCtxt;
use std::env;
use std::env::consts::{DLL_PREFIX, DLL_SUFFIX};
use std::mem;
use std::path::{Path, PathBuf};
use std::sync::atomic::{AtomicBool, Ordering};
use std::sync::OnceLock;
@ -162,29 +161,19 @@ pub(crate) fn run_in_thread_pool_with_globals<F: FnOnce() -> R + Send, R: Send>(
}
fn load_backend_from_dylib(early_dcx: &EarlyDiagCtxt, path: &Path) -> MakeBackendFn {
fn format_err(e: &(dyn std::error::Error + 'static)) -> String {
e.sources().map(|e| format!(": {e}")).collect()
}
let lib = unsafe { Library::new(path) }.unwrap_or_else(|err| {
let err = format!("couldn't load codegen backend {path:?}{}", format_err(&err));
early_dcx.early_fatal(err);
});
let backend_sym = unsafe { lib.get::<MakeBackendFn>(b"__rustc_codegen_backend") }
.unwrap_or_else(|e| {
match unsafe { load_symbol_from_dylib::<MakeBackendFn>(path, "__rustc_codegen_backend") } {
Ok(backend_sym) => backend_sym,
Err(DylibError::DlOpen(path, err)) => {
let err = format!("couldn't load codegen backend {path}{err}");
early_dcx.early_fatal(err);
}
Err(DylibError::DlSym(_path, err)) => {
let e = format!(
"`__rustc_codegen_backend` symbol lookup in the codegen backend failed{}",
format_err(&e)
"`__rustc_codegen_backend` symbol lookup in the codegen backend failed{err}",
);
early_dcx.early_fatal(e);
});
// Intentionally leak the dynamic library. We can't ever unload it
// since the library can make things that will live arbitrarily long.
let backend_sym = unsafe { backend_sym.into_raw() };
mem::forget(lib);
*backend_sym
}
}
}
/// Get the codegen backend based on the name and specified sysroot.