Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Simplify memory ordering intrinsics #97423

Merged
merged 1 commit into from
Jun 29, 2022
Merged

Simplify memory ordering intrinsics #97423

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
1 change: 1 addition & 0 deletions compiler/rustc_codegen_ssa/src/lib.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,7 @@
#![feature(associated_type_bounds)]
#![feature(strict_provenance)]
#![feature(int_roundings)]
#![feature(if_let_guard)]
#![recursion_limit = "256"]
#![allow(rustc::potential_query_instability)]

Expand Down
58 changes: 26 additions & 32 deletions compiler/rustc_codegen_ssa/src/mir/intrinsic.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -376,32 +376,23 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
}

// This requires that atomic intrinsics follow a specific naming pattern:
// "atomic_<operation>[_<ordering>]", and no ordering means SeqCst
name if name_str.starts_with("atomic_") => {
// "atomic_<operation>[_<ordering>]"
name if let Some(atomic) = name_str.strip_prefix("atomic_") => {
use crate::common::AtomicOrdering::*;
use crate::common::{AtomicRmwBinOp, SynchronizationScope};

let split: Vec<_> = name_str.split('_').collect();

let is_cxchg = split[1] == "cxchg" || split[1] == "cxchgweak";
let (order, failorder) = match split.len() {
2 => (SequentiallyConsistent, SequentiallyConsistent),
3 => match split[2] {
"unordered" => (Unordered, Unordered),
"relaxed" => (Relaxed, Relaxed),
"acq" => (Acquire, Acquire),
"rel" => (Release, Relaxed),
"acqrel" => (AcquireRelease, Acquire),
"failrelaxed" if is_cxchg => (SequentiallyConsistent, Relaxed),
"failacq" if is_cxchg => (SequentiallyConsistent, Acquire),
_ => bx.sess().fatal("unknown ordering in atomic intrinsic"),
},
4 => match (split[2], split[3]) {
("acq", "failrelaxed") if is_cxchg => (Acquire, Relaxed),
("acqrel", "failrelaxed") if is_cxchg => (AcquireRelease, Relaxed),
_ => bx.sess().fatal("unknown ordering in atomic intrinsic"),
},
_ => bx.sess().fatal("Atomic intrinsic not in correct format"),
let Some((instruction, ordering)) = atomic.split_once('_') else {
bx.sess().fatal("Atomic intrinsic missing memory ordering");
};

let parse_ordering = |bx: &Bx, s| match s {
"unordered" => Unordered,
"relaxed" => Relaxed,
"acquire" => Acquire,
"release" => Release,
"acqrel" => AcquireRelease,
"seqcst" => SequentiallyConsistent,
_ => bx.sess().fatal("unknown ordering in atomic intrinsic"),
};

let invalid_monomorphization = |ty| {
Expand All @@ -416,11 +407,14 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
);
};

match split[1] {
match instruction {
"cxchg" | "cxchgweak" => {
let Some((success, failure)) = ordering.split_once('_') else {
bx.sess().fatal("Atomic compare-exchange intrinsic missing failure memory ordering");
};
let ty = substs.type_at(0);
if int_type_width_signed(ty, bx.tcx()).is_some() || ty.is_unsafe_ptr() {
let weak = split[1] == "cxchgweak";
let weak = instruction == "cxchgweak";
let mut dst = args[0].immediate();
let mut cmp = args[1].immediate();
let mut src = args[2].immediate();
Expand All @@ -432,7 +426,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
cmp = bx.ptrtoint(cmp, bx.type_isize());
src = bx.ptrtoint(src, bx.type_isize());
}
let pair = bx.atomic_cmpxchg(dst, cmp, src, order, failorder, weak);
let pair = bx.atomic_cmpxchg(dst, cmp, src, parse_ordering(bx, success), parse_ordering(bx, failure), weak);
let val = bx.extract_value(pair, 0);
let success = bx.extract_value(pair, 1);
let val = bx.from_immediate(val);
Expand Down Expand Up @@ -460,11 +454,11 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
let llty = bx.type_isize();
let ptr_llty = bx.type_ptr_to(llty);
source = bx.pointercast(source, ptr_llty);
let result = bx.atomic_load(llty, source, order, size);
let result = bx.atomic_load(llty, source, parse_ordering(bx, ordering), size);
// ... and then cast the result back to a pointer
bx.inttoptr(result, bx.backend_type(layout))
} else {
bx.atomic_load(bx.backend_type(layout), source, order, size)
bx.atomic_load(bx.backend_type(layout), source, parse_ordering(bx, ordering), size)
}
} else {
return invalid_monomorphization(ty);
Expand All @@ -484,20 +478,20 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
ptr = bx.pointercast(ptr, ptr_llty);
val = bx.ptrtoint(val, bx.type_isize());
}
bx.atomic_store(val, ptr, order, size);
bx.atomic_store(val, ptr, parse_ordering(bx, ordering), size);
return;
} else {
return invalid_monomorphization(ty);
}
}

"fence" => {
bx.atomic_fence(order, SynchronizationScope::CrossThread);
bx.atomic_fence(parse_ordering(bx, ordering), SynchronizationScope::CrossThread);
return;
}

"singlethreadfence" => {
bx.atomic_fence(order, SynchronizationScope::SingleThread);
bx.atomic_fence(parse_ordering(bx, ordering), SynchronizationScope::SingleThread);
return;
}

Expand Down Expand Up @@ -531,7 +525,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
ptr = bx.pointercast(ptr, ptr_llty);
val = bx.ptrtoint(val, bx.type_isize());
}
bx.atomic_rmw(atom_op, ptr, val, order)
bx.atomic_rmw(atom_op, ptr, val, parse_ordering(bx, ordering))
} else {
return invalid_monomorphization(ty);
}
Expand Down
4 changes: 2 additions & 2 deletions compiler/rustc_error_codes/src/error_codes/E0093.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -24,12 +24,12 @@ functions are defined in `compiler/rustc_codegen_llvm/src/intrinsic.rs` and in
#![feature(intrinsics)]

extern "rust-intrinsic" {
fn atomic_fence(); // ok!
fn atomic_fence_seqcst(); // ok!
}

fn main() {
unsafe {
atomic_fence();
atomic_fence_seqcst();
}
}
```
Loading