rustrt: Make begin_unwind take a single file/line pointer

Smaller text size.

src/librustrt/unwind.rs

@@ -417,8 +417,8 @@ pub fn begin_unwind_fmt(msg: &fmt::Arguments, file_line: &(&'static str, uint))
     begin_unwind_inner(box String::from_utf8(v).unwrap(), file_line)
 }
 
-// FIXME: Need to change expr_fail in AstBuilder to change this to &(str, uint)
 /// This is the entry point of unwinding for fail!() and assert!().
+#[cfg(stage0)]
 #[inline(never)] #[cold] // avoid code bloat at the call sites as much as possible
 pub fn begin_unwind<M: Any + Send>(msg: M, file: &'static str, line: uint) -> ! {
     // Note that this should be the only allocation performed in this code path.
@@ -432,6 +432,21 @@ pub fn begin_unwind<M: Any + Send>(msg: M, file: &'static str, line: uint) -> !
     begin_unwind_inner(box msg, &(file, line))
 }
 
+/// This is the entry point of unwinding for fail!() and assert!().
+#[cfg(not(stage0))]
+#[inline(never)] #[cold] // avoid code bloat at the call sites as much as possible
+pub fn begin_unwind<M: Any + Send>(msg: M, file_line: &(&'static str, uint)) -> ! {
+    // Note that this should be the only allocation performed in this code path.
+    // Currently this means that fail!() on OOM will invoke this code path,
+    // but then again we're not really ready for failing on OOM anyway. If
+    // we do start doing this, then we should propagate this allocation to
+    // be performed in the parent of this task instead of the task that's
+    // failing.
+
+    // see below for why we do the `Any` coercion here.
+    begin_unwind_inner(box msg, file_line)
+}
+
 /// The core of the unwinding.
 ///
 /// This is non-generic to avoid instantiation bloat in other crates

src/libstd/macros.rs

@@ -37,6 +37,39 @@
 /// fail!("this is a {} {message}", "fancy", message = "message");
 /// ```
 #[macro_export]
+#[cfg(not(stage0))]
+macro_rules! fail(
+    () => ({
+        fail!("explicit failure")
+    });
+    ($msg:expr) => ({
+        // static requires less code at runtime, more constant data
+        static FILE_LINE: (&'static str, uint) = (file!(), line!());
+        ::std::rt::begin_unwind($msg, &FILE_LINE)
+    });
+    ($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) -> ! {
+            static FILE_LINE: (&'static str, uint) = (file!(), line!());
+            ::std::rt::begin_unwind_fmt(fmt, &FILE_LINE)
+        }
+        format_args!(run_fmt, $fmt, $($arg)*)
+    });
+)
+
+#[macro_export]
+#[cfg(stage0)]
 macro_rules! fail(
     () => ({
         fail!("explicit failure")

src/libsyntax/ext/build.rs

@@ -690,6 +690,13 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
 
     fn expr_fail(&self, span: Span, msg: InternedString) -> Gc<ast::Expr> {
         let loc = self.codemap().lookup_char_pos(span.lo);
+        let expr_file = self.expr_str(span,
+                                      token::intern_and_get_ident(loc.file
+                                                                  .name
+                                                                  .as_slice()));
+        let expr_line = self.expr_uint(span, loc.line);
+        let expr_file_line_tuple = self.expr_tuple(span, vec!(expr_file, expr_line));
+        let expr_file_line_ptr = self.expr_addr_of(span, expr_file_line_tuple);
         self.expr_call_global(
             span,
             vec!(
@@ -698,11 +705,7 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
                 self.ident_of("begin_unwind")),
             vec!(
                 self.expr_str(span, msg),
-                self.expr_str(span,
-                              token::intern_and_get_ident(loc.file
-                                                             .name
-                                                             .as_slice())),
-                self.expr_uint(span, loc.line)))
+                expr_file_line_ptr))
     }
 
     fn expr_unreachable(&self, span: Span) -> Gc<ast::Expr> {