New upstream version 1.31.0~beta.4+dfsg1

[rustc.git] / src / libstd / sys / wasm / thread.rs

diff --git a/src/libstd/sys/wasm/thread.rs b/src/libstd/sys/wasm/thread.rs
index 8173a62421117d4bb11b034a1bcee3978458a84c..4ad89c42b92dca0bfa921c1caabd5d2aeb3d5730 100644 (file)
--- a/src/libstd/sys/wasm/thread.rs
+++ b/src/libstd/sys/wasm/thread.rs
@@ -33,10 +33,31 @@ impl Thread {
         // nope
     }
 
+    #[cfg(not(target_feature = "atomics"))]
     pub fn sleep(_dur: Duration) {
         panic!("can't sleep");
     }
 
+    #[cfg(target_feature = "atomics")]
+    pub fn sleep(dur: Duration) {
+        use arch::wasm32::atomic;
+        use cmp;
+
+        // Use an atomic wait to block the current thread artificially with a
+        // timeout listed. Note that we should never be notified (return value
+        // of 0) or our comparison should never fail (return value of 1) so we
+        // should always only resume execution through a timeout (return value
+        // 2).
+        let mut nanos = dur.as_nanos();
+        while nanos > 0 {
+            let amt = cmp::min(i64::max_value() as u128, nanos);
+            let mut x = 0;
+            let val = unsafe { atomic::wait_i32(&mut x, 0, amt as i64) };
+            debug_assert_eq!(val, 2);
+            nanos -= amt;
+        }
+    }
+
     pub fn join(self) {
         match self.0 {}
     }
@@ -48,3 +69,49 @@ pub mod guard {
     pub unsafe fn init() -> Option<Guard> { None }
     pub unsafe fn deinit() {}
 }
+
+cfg_if! {
+    if #[cfg(all(target_feature = "atomics", feature = "wasm-bindgen-threads"))] {
+        #[link(wasm_import_module = "__wbindgen_thread_xform__")]
+        extern {
+            fn __wbindgen_current_id() -> u32;
+            fn __wbindgen_tcb_get() -> u32;
+            fn __wbindgen_tcb_set(ptr: u32);
+        }
+        pub fn my_id() -> u32 {
+            unsafe { __wbindgen_current_id() }
+        }
+
+        // These are currently only ever used in `thread_local_atomics.rs`, if
+        // you'd like to use them be sure to update that and make sure everyone
+        // agrees what's what.
+        pub fn tcb_get() -> *mut u8 {
+            use mem;
+            assert_eq!(mem::size_of::<*mut u8>(), mem::size_of::<u32>());
+            unsafe { __wbindgen_tcb_get() as *mut u8 }
+        }
+
+        pub fn tcb_set(ptr: *mut u8) {
+            unsafe { __wbindgen_tcb_set(ptr as u32); }
+        }
+
+        // FIXME: still need something for hooking exiting a thread to free
+        // data...
+
+    } else if #[cfg(target_feature = "atomics")] {
+        pub fn my_id() -> u32 {
+            panic!("thread ids not implemented on wasm with atomics yet")
+        }
+
+        pub fn tcb_get() -> *mut u8 {
+            panic!("thread local data not implemented on wasm with atomics yet")
+        }
+
+        pub fn tcb_set(ptr: *mut u8) {
+            panic!("thread local data not implemented on wasm with atomics yet")
+        }
+    } else {
+        // stubbed out because no functions actually access these intrinsics
+        // unless atomics are enabled
+    }
+}