Added relaxed atomics and used them in the global heap

src/libcore/rt/global_heap.rs

@@ -14,10 +14,24 @@ use c_malloc = libc::malloc;
 use c_free = libc::free;
 use managed::raw::{BoxHeaderRepr, BoxRepr};
 use cast::transmute;
-use unstable::intrinsics::{atomic_xadd,atomic_xsub};
 use ptr::null;
 use intrinsic::TyDesc;
 
+#[cfg(stage0)]
+use unstable::intrinsics::{atomic_xadd,atomic_xsub};
+#[cfg(not(stage0))]
+use unstable::intrinsics::{atomic_xadd_relaxed,atomic_xsub_relaxed};
+
+#[cfg(stage0)]
+unsafe fn atomic_xadd_relaxed(dst:&mut int, src:int) -> int {
+    atomic_xadd(dst, src)
+}
+
+#[cfg(stage0)]
+unsafe fn atomic_xsub_relaxed(dst:&mut int, src:int) -> int {
+    atomic_xsub(dst, src)
+}
+
 pub unsafe fn malloc(td: *TypeDesc, size: uint) -> *c_void {
     assert!(td.is_not_null());
 
@@ -35,7 +49,7 @@ pub unsafe fn malloc(td: *TypeDesc, size: uint) -> *c_void {
     box.header.next = null();
 
     let exchange_count = &mut *exchange_count_ptr();
-    atomic_xadd(exchange_count, 1);
+    atomic_xadd_relaxed(exchange_count, 1);
 
     return transmute(box);
 }
@@ -53,7 +67,7 @@ pub unsafe fn malloc_raw(size: uint) -> *c_void {
 
 pub unsafe fn free(ptr: *c_void) {
     let exchange_count = &mut *exchange_count_ptr();
-    atomic_xsub(exchange_count, 1);
+    atomic_xsub_relaxed(exchange_count, 1);
 
     assert!(ptr.is_not_null());
     c_free(ptr);

src/libcore/unstable/intrinsics.rs

@@ -69,13 +69,19 @@ pub extern "rust-intrinsic" {
     pub fn atomic_xadd_acq(dst: &mut int, src: int) -> int;
     /// Atomic addition, release ordering.
     pub fn atomic_xadd_rel(dst: &mut int, src: int) -> int;
+    /// Atomic addition, relaxed ordering
+    #[cfg(not(stage0))]
+    pub fn atomic_xadd_relaxed(dst: &mut int, src: int) -> int;
 
     /// Atomic subtraction, sequentially consistent.
     pub fn atomic_xsub(dst: &mut int, src: int) -> int;
     /// Atomic subtraction, acquire ordering.
     pub fn atomic_xsub_acq(dst: &mut int, src: int) -> int;
     /// Atomic subtraction, release ordering.
     pub fn atomic_xsub_rel(dst: &mut int, src: int) -> int;
+    /// Atomic subtraction, relaxed ordering
+    #[cfg(not(stage0))]
+    pub fn atomic_xsub_relaxed(dst: &mut int, src: int) -> int;
 
     /// The size of a type in bytes.
     ///

src/librustc/middle/trans/foreign.rs

@@ -9,7 +9,7 @@
 // except according to those terms.
 
 use back::{link, abi};
-use lib::llvm::{SequentiallyConsistent, Acquire, Release, Xchg};
+use lib::llvm::{SequentiallyConsistent, Acquire, Release, Xchg, Monotonic};
 use lib::llvm::{TypeRef, ValueRef};
 use lib;
 use middle::trans::base::*;
@@ -657,6 +657,13 @@ pub fn trans_intrinsic(ccx: @CrateContext,
                                 Release);
             Store(bcx, old, fcx.llretptr.get());
         }
+        ~"atomic_xadd_relaxed" => {
+            let old = AtomicRMW(bcx, lib::llvm::Add,
+                                get_param(decl, first_real_arg),
+                                get_param(decl, first_real_arg + 1u),
+                                Monotonic);
+            Store(bcx, old, fcx.llretptr.get());
+        }
         ~"atomic_xsub" => {
             let old = AtomicRMW(bcx, lib::llvm::Sub,
                                 get_param(decl, first_real_arg),
@@ -678,6 +685,13 @@ pub fn trans_intrinsic(ccx: @CrateContext,
                                 Release);
             Store(bcx, old, fcx.llretptr.get());
         }
+        ~"atomic_xsub_relaxed" => {
+            let old = AtomicRMW(bcx, lib::llvm::Sub,
+                                get_param(decl, first_real_arg),
+                                get_param(decl, first_real_arg + 1u),
+                                Monotonic);
+            Store(bcx, old, fcx.llretptr.get());
+        }
         ~"size_of" => {
             let tp_ty = substs.tys[0];
             let lltp_ty = type_of::type_of(ccx, tp_ty);

src/librustc/middle/trans/type_use.rs

@@ -130,6 +130,7 @@ pub fn type_uses_for(ccx: @CrateContext, fn_id: def_id, n_tps: uint)
                 ~"atomic_xadd"     | ~"atomic_xsub"     |
                 ~"atomic_xchg_acq" | ~"atomic_xadd_acq" |
                 ~"atomic_xsub_acq" | ~"atomic_xchg_rel" |
+                ~"atomic_xadd_relaxed" | ~"atomic_xsub_relaxed" |
                 ~"atomic_xadd_rel" | ~"atomic_xsub_rel" => 0,
 
                 ~"visit_tydesc"  | ~"forget" | ~"frame_address" |

src/librustc/middle/typeck/check/mod.rs

@@ -3498,6 +3498,7 @@ pub fn check_intrinsic_type(ccx: @mut CrateCtxt, it: @ast::foreign_item) {
          ty::mk_nil())
       }
       ~"atomic_xchg"     | ~"atomic_xadd"     | ~"atomic_xsub"     |
+      ~"atomic_xadd_relaxed"     | ~"atomic_xsub_relaxed"          |
       ~"atomic_xchg_acq" | ~"atomic_xadd_acq" | ~"atomic_xsub_acq" |
       ~"atomic_xchg_rel" | ~"atomic_xadd_rel" | ~"atomic_xsub_rel" => {
         (0,