Add AbiSet and integrate it into the AST.

I believe this patch incorporates all expected syntax changes from extern
function reform (#3678). You can now write things like:

    extern "<abi>" fn foo(s: S) -> T { ... }
    extern "<abi>" mod { ... }
    extern "<abi>" fn(S) -> T

The ABI for foreign functions is taken from this syntax (rather than from an
annotation).  We support the full ABI specification I described on the mailing
list.  The correct ABI is chosen based on the target architecture.

Calls by pointer to C functions are not yet supported, and the Rust type of
crust fns is still *u8.

src/test/auxiliary/cci_intrinsic.rs

@@ -10,7 +10,7 @@
 
 pub mod rusti {
     #[abi = "rust-intrinsic"]
-    pub extern {
+    pub extern "rust-intrinsic" {
         fn atomic_cxchg(dst: &mut int, old: int, src: int) -> int;
         fn atomic_cxchg_acq(dst: &mut int, old: int, src: int) -> int;
         fn atomic_cxchg_rel(dst: &mut int, old: int, src: int) -> int;
@@ -18,11 +18,11 @@ pub mod rusti {
         fn atomic_xchg(dst: &mut int, src: int) -> int;
         fn atomic_xchg_acq(dst: &mut int, src: int) -> int;
         fn atomic_xchg_rel(dst: &mut int, src: int) -> int;
-        
+
         fn atomic_xadd(dst: &mut int, src: int) -> int;
         fn atomic_xadd_acq(dst: &mut int, src: int) -> int;
         fn atomic_xadd_rel(dst: &mut int, src: int) -> int;
-        
+
         fn atomic_xsub(dst: &mut int, src: int) -> int;
         fn atomic_xsub_acq(dst: &mut int, src: int) -> int;
         fn atomic_xsub_rel(dst: &mut int, src: int) -> int;

src/test/compile-fail/block-coerce-no-2.rs

@@ -19,5 +19,5 @@ fn main() {
     }
 
     f(g);
-    //~^ ERROR mismatched types: expected `extern fn(extern fn(extern fn()))`
+    //~^ ERROR mismatched types: expected `extern "Rust" fn(extern "Rust" fn(extern "Rust" fn()))`
 }

src/test/compile-fail/main-wrong-type-2.rs

@@ -9,5 +9,5 @@
 // except according to those terms.
 
 fn main() -> char {
-//~^ ERROR Wrong type in main function: found `extern fn() -> char`
+//~^ ERROR Wrong type in main function: found `extern "Rust" fn() -> char`
 }

src/test/compile-fail/main-wrong-type.rs

@@ -14,5 +14,5 @@ struct S {
 }
 
 fn main(foo: S) {
-//~^ ERROR Wrong type in main function: found `extern fn(S)`
+//~^ ERROR Wrong type in main function: found `extern "Rust" fn(S)`
 }

src/test/compile-fail/missing-do.rs

@@ -14,6 +14,6 @@ fn foo(f: &fn()) { f() }
 
 fn main() {
     ~"" || 42; //~ ERROR binary operation || cannot be applied to type `~str`
-    foo || {}; //~ ERROR binary operation || cannot be applied to type `extern fn(&fn())`
+    foo || {}; //~ ERROR binary operation || cannot be applied to type `extern "Rust" fn(&fn())`
     //~^ NOTE did you forget the `do` keyword for the call?
 }

src/test/pretty/fn-types.rs

@@ -10,7 +10,7 @@
 
 // pp-exact
 
-fn from_foreign_fn(x: extern fn()) { }
+fn from_foreign_fn(x: extern "Rust" fn()) { }
 fn from_stack_closure(x: &fn()) { }
 fn from_box_closure(x: @fn()) { }
 fn from_unique_closure(x: ~fn()) { }

src/test/run-pass/intrinsic-alignment.rs

@@ -12,7 +12,7 @@
 
 mod rusti {
     #[abi = "rust-intrinsic"]
-    pub extern {
+    pub extern "rust-intrinsic" {
         pub fn pref_align_of<T>() -> uint;
         pub fn min_align_of<T>() -> uint;
     }

src/test/run-pass/intrinsic-atomics.rs

@@ -10,7 +10,7 @@
 
 mod rusti {
     #[abi = "rust-intrinsic"]
-    pub extern {
+    pub extern "rust-intrinsic" {
         pub fn atomic_cxchg(dst: &mut int, old: int, src: int) -> int;
         pub fn atomic_cxchg_acq(dst: &mut int, old: int, src: int) -> int;
         pub fn atomic_cxchg_rel(dst: &mut int, old: int, src: int) -> int;
@@ -18,11 +18,11 @@ mod rusti {
         pub fn atomic_xchg(dst: &mut int, src: int) -> int;
         pub fn atomic_xchg_acq(dst: &mut int, src: int) -> int;
         pub fn atomic_xchg_rel(dst: &mut int, src: int) -> int;
-        
+
         pub fn atomic_xadd(dst: &mut int, src: int) -> int;
         pub fn atomic_xadd_acq(dst: &mut int, src: int) -> int;
         pub fn atomic_xadd_rel(dst: &mut int, src: int) -> int;
-        
+
         pub fn atomic_xsub(dst: &mut int, src: int) -> int;
         pub fn atomic_xsub_acq(dst: &mut int, src: int) -> int;
         pub fn atomic_xsub_rel(dst: &mut int, src: int) -> int;

src/test/run-pass/intrinsic-frame-address.rs

@@ -13,7 +13,7 @@
 
 mod rusti {
     #[abi = "rust-intrinsic"]
-    pub extern {
+    pub extern "rust-intrinsic" {
         pub fn frame_address(f: &once fn(*u8));
     }
 }

src/test/run-pass/intrinsic-move-val.rs

@@ -10,7 +10,7 @@
 
 mod rusti {
     #[abi = "rust-intrinsic"]
-    pub extern {
+    pub extern "rust-intrinsic" {
         pub fn move_val_init<T>(dst: &mut T, +src: T);
         pub fn move_val<T>(dst: &mut T, +src: T);
     }

src/test/run-pass/intrinsics-integer.rs

@@ -13,8 +13,8 @@
 extern mod std;
 
 mod rusti {
-    #[abi = "rust-intrinsic"]  
-    pub extern {
+    #[abi = "rust-intrinsic"]
+    pub extern "rust-intrinsic" {
         fn ctpop8(x: i8) -> i8;
         fn ctpop16(x: i16) -> i16;
         fn ctpop32(x: i32) -> i32;

src/test/run-pass/intrinsics-math.rs

@@ -15,8 +15,8 @@ extern mod std;
 use std::cmp::FuzzyEq;
 
 mod rusti {
-    #[abi = "rust-intrinsic"]  
-    pub extern {
+    #[abi = "rust-intrinsic"]
+    pub extern "rust-intrinsic" {
         fn sqrtf32(x: f32) -> f32;
         fn sqrtf64(x: f64) -> f64;
         fn powif32(a: f32, x: i32) -> f32;

src/test/run-pass/issue-2718.rs

@@ -45,7 +45,6 @@ pub mod pipes {
         }
     }
 
-    #[abi = "rust-intrinsic"]
     mod rusti {
       pub fn atomic_xchg(_dst: &mut int, _src: int) -> int { fail!(); }
       pub fn atomic_xchg_acq(_dst: &mut int, _src: int) -> int { fail!(); }

src/test/run-pass/morestack-address.rs

@@ -11,7 +11,7 @@
 mod rusti {
     #[nolink]
     #[abi = "rust-intrinsic"]
-    pub extern {
+    pub extern "rust-intrinsic" {
         pub fn morestack_addr() -> *();
     }
 }

src/test/run-pass/rec-align-u32.rs

@@ -12,7 +12,7 @@
 
 mod rusti {
     #[abi = "rust-intrinsic"]
-    pub extern {
+    pub extern "rust-intrinsic" {
         pub fn pref_align_of<T>() -> uint;
         pub fn min_align_of<T>() -> uint;
     }

src/test/run-pass/rec-align-u64.rs

@@ -12,7 +12,7 @@
 
 mod rusti {
     #[abi = "rust-intrinsic"]
-    pub extern {
+    pub extern "rust-intrinsic" {
         pub fn pref_align_of<T>() -> uint;
         pub fn min_align_of<T>() -> uint;
     }

src/test/run-pass/x86stdcall2.rs

@@ -19,7 +19,7 @@ mod kernel32 {
 
     #[cfg(target_os = "win32")]
     #[abi = "stdcall"]
-    pub extern {
+    pub extern "stdcall" {
         pub fn GetProcessHeap() -> HANDLE;
         pub fn HeapAlloc(hHeap: HANDLE, dwFlags: DWORD, dwBytes: SIZE_T)
                       -> LPVOID;