rustc: Process #[cfg]/#[cfg_attr] on crates

This commit implements processing these two attributes at the crate level as
well as at the item level. When #[cfg] is applied at the crate level, then the
entire crate will be omitted if the cfg doesn't match. The #[cfg_attr] attribute
is processed as usual in that the attribute is included or not depending on
whether the cfg matches.

This was spurred on by motivations of #18585 where #[cfg_attr] annotations will
be applied at the crate-level.

cc #18585

src/test/auxiliary/stability_cfg1.rs

@@ -0,0 +1,12 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![cfg_attr(foo, experimental)]
+#![cfg_attr(not(foo), stable)]

src/test/auxiliary/stability_cfg2.rs

@@ -0,0 +1,15 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// compile-flags:--cfg foo
+
+#![cfg_attr(foo, experimental)]
+#![cfg_attr(not(foo), stable)]
+

src/test/compile-fail/cfg-in-crate-1.rs

@@ -0,0 +1,13 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// error-pattern:main function not found
+
+#![cfg(bar)]

src/test/compile-fail/lint-stability.rs

@@ -10,6 +10,8 @@
 
 // aux-build:lint_stability.rs
 // aux-build:inherited_stability.rs
+// aux-build:stability_cfg1.rs
+// aux-build:stability_cfg2.rs
 
 #![feature(globs, phase)]
 #![deny(unstable)]
@@ -18,6 +20,9 @@
 #![allow(dead_code)]
 
 mod cross_crate {
+    extern crate stability_cfg1;
+    extern crate stability_cfg2; //~ ERROR: use of experimental item
+
     #[phase(plugin, link)]
     extern crate lint_stability; //~ ERROR: use of unmarked item
     use self::lint_stability::*;

src/test/run-make/graphviz-flowgraph/f03.dot-expected.dot

@@ -2,10 +2,10 @@ digraph block {
     N0[label="entry"];
     N1[label="exit"];
     N2[label="expr 3i"];
-    N3[label="expr 33i"];
-    N4[label="expr 3i + 33i"];
-    N5[label="stmt 3i + 33i;"];
-    N6[label="block { 3i + 33i; }"];
+    N3[label="expr 4"];
+    N4[label="expr 3i + 4"];
+    N5[label="stmt 3i + 4;"];
+    N6[label="block { 3i + 4; }"];
     N0 -> N2;
     N2 -> N3;
     N3 -> N4;

src/test/run-make/graphviz-flowgraph/f03.rs

@@ -9,5 +9,5 @@
 // except according to those terms.
 
 pub fn expr_add_3() {
-    3i + 33i;
+    3i + 4;
 }

src/test/run-pass/cfg-in-crate-1.rs

@@ -0,0 +1,16 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// compile-flags: --cfg bar -D warnings
+// ignore-pretty
+
+#![cfg(bar)]
+
+fn main() {}