---

yaml
---
r: 151741
b: refs/heads/try2
c: f2af4ca
h: refs/heads/master
i:
  151739: c74db03
v: v3

Author: alexcrichton

[refs]

@@ -5,7 +5,7 @@ refs/heads/snap-stage3: 78a7676898d9f80ab540c6df5d4c9ce35bb50463
 refs/heads/try: 519addf6277dbafccbb4159db4b710c37eaa2ec5
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/heads/ndm: f3868061cd7988080c30d6d5bf352a5a5fe2460b
-refs/heads/try2: c25556865205e6978e6bc9eb0e6d5e151e1a68d9
+refs/heads/try2: f2af4ca3e65ebef040df633c9d563b579540898e
 refs/heads/dist-snap: ba4081a5a8573875fed17545846f6f6902c8ba8d
 refs/tags/release-0.2: c870d2dffb391e14efb05aa27898f1f6333a9596
 refs/tags/release-0.3: b5f0d0f648d9a6153664837026ba1be43d3e2503

branches/try2/src/libcore/macros.rs

@@ -14,11 +14,29 @@
 #[macro_export]
 macro_rules! fail(
     () => (
-        fail!("explicit failure")
+        fail!("{}", "explicit failure")
     );
     ($msg:expr) => (
-        ::core::failure::begin_unwind($msg, file!(), line!())
+        fail!("{}", $msg)
     );
+    ($fmt:expr, $($arg:tt)*) => ({
+        // a closure can't have return type !, so we need a full
+        // function to pass to format_args!, *and* we need the
+        // file and line numbers right here; so an inner bare fn
+        // is our only choice.
+        //
+        // LLVM doesn't tend to inline this, presumably because begin_unwind_fmt
+        // is #[cold] and #[inline(never)] and because this is flagged as cold
+        // as returning !. We really do want this to be inlined, however,
+        // because it's just a tiny wrapper. Small wins (156K to 149K in size)
+        // were seen when forcing this to be inlined, and that number just goes
+        // up with the number of calls to fail!()
+        #[inline(always)]
+        fn run_fmt(fmt: &::std::fmt::Arguments) -> ! {
+            ::core::failure::begin_unwind(fmt, file!(), line!())
+        }
+        format_args!(run_fmt, $fmt, $($arg)*)
+    });
 )
 
 /// Runtime assertion, for details see std::macros
@@ -29,6 +47,11 @@ macro_rules! assert(
             fail!(concat!("assertion failed: ", stringify!($cond)))
         }
     );
+    ($cond:expr, $($arg:tt)*) => (
+        if !$cond {
+            fail!($($arg)*)
+        }
+    );
 )
 
 /// Runtime assertion, disableable at compile time