bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Auto merge of #77611 - oli-obk:atomic_miri_leakage, r=nagisa

Browse source 
Directly use raw pointers in `AtomicPtr` store/load

I was unable to find any reason for this limitation in the latest source of LLVM or in the documentation [here](http://llvm.org/docs/Atomics.html#libcalls-atomic).

fixes https://github.com/rust-lang/miri/issues/1574
This commit is contained in:
bors 2020-12-09 19:53:23 +00:00
commit f0f68778f7
4 changed files with 73 additions and 30 deletions
Download patch file Download diff file Expand all files Collapse all files

55
compiler/rustc_codegen_ssa/src/mir/intrinsic.rs
View file

@ -437,16 +437,20 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
match split[1] {
"cxchg" | "cxchgweak" => {
let ty = substs.type_at(0);
if int_type_width_signed(ty, bx.tcx()).is_some() {
if int_type_width_signed(ty, bx.tcx()).is_some() || ty.is_unsafe_ptr() {
let weak = split[1] == "cxchgweak";
let pair = bx.atomic_cmpxchg(
args[0].immediate(),
args[1].immediate(),
args[2].immediate(),
order,
failorder,
weak,
);
let mut dst = args[0].immediate();
let mut cmp = args[1].immediate();
let mut src = args[2].immediate();
if ty.is_unsafe_ptr() {
// Some platforms do not support atomic operations on pointers,
// so we cast to integer first.
let ptr_llty = bx.type_ptr_to(bx.type_isize());
dst = bx.pointercast(dst, ptr_llty);
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 val = bx.extract_value(pair, 0);
let success = bx.extract_value(pair, 1);
let val = bx.from_immediate(val);
@ -464,9 +468,23 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
"load" => {
let ty = substs.type_at(0);
if int_type_width_signed(ty, bx.tcx()).is_some() {
let size = bx.layout_of(ty).size;
bx.atomic_load(args[0].immediate(), order, size)
if int_type_width_signed(ty, bx.tcx()).is_some() || ty.is_unsafe_ptr() {
let layout = bx.layout_of(ty);
let size = layout.size;
let mut source = args[0].immediate();
if ty.is_unsafe_ptr() {
// Some platforms do not support atomic operations on pointers,
// so we cast to integer first...
let ptr_llty = bx.type_ptr_to(bx.type_isize());
source = bx.pointercast(source, ptr_llty);
}
let result = bx.atomic_load(source, order, size);
if ty.is_unsafe_ptr() {
// ... and then cast the result back to a pointer
bx.inttoptr(result, bx.backend_type(layout))
} else {
result
}
} else {
return invalid_monomorphization(ty);
}
@ -474,9 +492,18 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
"store" => {
let ty = substs.type_at(0);
if int_type_width_signed(ty, bx.tcx()).is_some() {
if int_type_width_signed(ty, bx.tcx()).is_some() || ty.is_unsafe_ptr() {
let size = bx.layout_of(ty).size;
bx.atomic_store(args[1].immediate(), args[0].immediate(), order, size);
let mut val = args[1].immediate();
let mut ptr = args[0].immediate();
if ty.is_unsafe_ptr() {
// Some platforms do not support atomic operations on pointers,
// so we cast to integer first.
let ptr_llty = bx.type_ptr_to(bx.type_isize());
ptr = bx.pointercast(ptr, ptr_llty);
val = bx.ptrtoint(val, bx.type_isize());
}
bx.atomic_store(val, ptr, order, size);
return;
} else {
return invalid_monomorphization(ty);