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Cleanup LLVM multi-threading checks

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The support for runtime multi-threading was removed from LLVM. Calls to
`LLVMStartMultithreaded` became no-ops equivalent to checking if LLVM
was compiled with support for threads http://reviews.llvm.org/D4216.
This commit is contained in:
Tomasz Miąsko 2021-10-12 00:00:00 +00:00
parent ffdf18d144
commit aa3bf01889
2 changed files with 6 additions and 16 deletions
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2
compiler/rustc_codegen_llvm/src/llvm/ffi.rs
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@ -1743,7 +1743,7 @@ extern "C" {
pub fn LLVMDisposeMessage(message: *mut c_char); pub fn LLVMDisposeMessage(message: *mut c_char);
pub fn LLVMStartMultithreaded() -> Bool; pub fn LLVMIsMultithreaded() -> Bool;
/// Returns a string describing the last error caused by an LLVMRust* call. /// Returns a string describing the last error caused by an LLVMRust* call.
pub fn LLVMRustGetLastError() -> *const c_char; pub fn LLVMRustGetLastError() -> *const c_char;

20
compiler/rustc_codegen_llvm/src/llvm_util.rs
View file

@ -17,35 +17,25 @@ use std::path::Path;
use std::ptr; use std::ptr;
use std::slice; use std::slice;
use std::str; use std::str;
use std::sync::atomic::{AtomicBool, Ordering};
use std::sync::Once; use std::sync::Once;
static POISONED: AtomicBool = AtomicBool::new(false);
static INIT: Once = Once::new(); static INIT: Once = Once::new();
pub(crate) fn init(sess: &Session) { pub(crate) fn init(sess: &Session) {
unsafe { unsafe {
// Before we touch LLVM, make sure that multithreading is enabled. // Before we touch LLVM, make sure that multithreading is enabled.
INIT.call_once(|| { if llvm::LLVMIsMultithreaded() != 1 {
if llvm::LLVMStartMultithreaded() != 1 { bug!("LLVM compiled without support for threads");
// use an extra bool to make sure that all future usage of LLVM
// cannot proceed despite the Once not running more than once.
POISONED.store(true, Ordering::SeqCst);
} }
INIT.call_once(|| {
configure_llvm(sess); configure_llvm(sess);
}); });
if POISONED.load(Ordering::SeqCst) {
bug!("couldn't enable multi-threaded LLVM");
}
} }
} }
fn require_inited() { fn require_inited() {
INIT.call_once(|| bug!("llvm is not initialized")); if !INIT.is_completed() {
if POISONED.load(Ordering::SeqCst) { bug!("LLVM is not initialized");
bug!("couldn't enable multi-threaded LLVM");
} }
} }