auto merge of #8535 : nikomatsakis/rust/issue-3678-wrappers-be-gone-2, r=graydon

Long-standing branch to remove foreign function wrappers altogether. Calls to C functions are done "in place" with no stack manipulation; the scheme relies entirely on the correct use of `#[fixed_stack_segment]` to guarantee adequate stack space. A linter is added to detect when `#[fixed_stack_segment]` annotations are missing. An `externfn!` macro is added to make it easier to declare foreign fns and wrappers in one go: this macro may need some refinement, though, for example it might be good to be able to declare a group of foreign fns. I leave that for future work (hopefully somebody else's work :) ).

Fixes #3678.

2 files changed, 15 insertions, 12 deletions

diff --git a/src/libstd/task/local_data_priv.rs b/src/libstd/task/local_data_priv.rs
index 3a11dee3138..8132bfe5377 100644
--- a/src/libstd/task/local_data_priv.rs
+++ b/src/libstd/task/local_data_priv.rs
@@ -147,7 +147,7 @@ pub unsafe fn local_pop<T: 'static>(handle: Handle,
                 // above.
                 let data = match util::replace(entry, None) {
                     Some((_, data, _)) => data,
-                    None => libc::abort(),
+                    None => abort(),
                 };
 
                 // Move `data` into transmute to get out the memory that it
@@ -252,7 +252,7 @@ unsafe fn local_get_with<T: 'static, U>(handle: Handle,
                         }
                     }
                 }
-                _ => libc::abort()
+                _ => abort()
             }
 
             // n.b. 'data' and 'loans' are both invalid pointers at the point
@@ -262,7 +262,7 @@ unsafe fn local_get_with<T: 'static, U>(handle: Handle,
             if return_loan {
                 match map[i] {
                     Some((_, _, ref mut loan)) => { *loan = NoLoan; }
-                    None => { libc::abort(); }
+                    None => { abort(); }
                 }
             }
             return ret;
@@ -270,6 +270,12 @@ unsafe fn local_get_with<T: 'static, U>(handle: Handle,
     }
 }
 
+fn abort() -> ! {
+    #[fixed_stack_segment]; #[inline(never)];
+
+    unsafe { libc::abort() }
+}
+
 pub unsafe fn local_set<T: 'static>(handle: Handle,
                                     key: local_data::Key<T>,
                                     data: T) {
diff --git a/src/libstd/task/mod.rs b/src/libstd/task/mod.rs
index 2c79f1c4ded..0d2e62a7700 100644
--- a/src/libstd/task/mod.rs
+++ b/src/libstd/task/mod.rs
@@ -1045,15 +1045,12 @@ fn test_spawn_sched_childs_on_default_sched() {
 mod testrt {
     use libc;
 
-    #[nolink]
-    extern {
-        pub fn rust_dbg_lock_create() -> *libc::c_void;
-        pub fn rust_dbg_lock_destroy(lock: *libc::c_void);
-        pub fn rust_dbg_lock_lock(lock: *libc::c_void);
-        pub fn rust_dbg_lock_unlock(lock: *libc::c_void);
-        pub fn rust_dbg_lock_wait(lock: *libc::c_void);
-        pub fn rust_dbg_lock_signal(lock: *libc::c_void);
-    }
+    externfn!(fn rust_dbg_lock_create() -> *libc::c_void)
+    externfn!(fn rust_dbg_lock_destroy(lock: *libc::c_void))
+    externfn!(fn rust_dbg_lock_lock(lock: *libc::c_void))
+    externfn!(fn rust_dbg_lock_unlock(lock: *libc::c_void))
+    externfn!(fn rust_dbg_lock_wait(lock: *libc::c_void))
+    externfn!(fn rust_dbg_lock_signal(lock: *libc::c_void))
 }
 
 #[test]