rustc: Add inline(maybe), which only writes the AST to crate metadata.

src/librustc/metadata/encoder.rs

@@ -719,7 +719,7 @@ fn purity_static_method_family(p: purity) -> char {
 fn should_inline(attrs: &[attribute]) -> bool {
     match attr::find_inline_attr(attrs) {
         attr::ia_none | attr::ia_never  => false,
-        attr::ia_hint | attr::ia_always => true
+        attr::ia_maybe | attr::ia_hint | attr::ia_always => true
     }
 }
 

src/librustc/middle/trans/base.rs

@@ -452,7 +452,7 @@ pub fn set_inline_hint_if_appr(attrs: &[ast::attribute],
       attr::ia_hint => set_inline_hint(llfn),
       attr::ia_always => set_always_inline(llfn),
       attr::ia_never => set_no_inline(llfn),
-      attr::ia_none => { /* fallthrough */ }
+      attr::ia_maybe | attr::ia_none => { /* fallthrough */ }
     }
 }
 

src/librustc/middle/trans/reachable.rs

@@ -117,15 +117,15 @@ fn traverse_public_item(cx: @mut ctx, item: @item) {
       }
       item_fn(_, _, _, ref generics, ref blk) => {
         if generics.ty_params.len() > 0u ||
-           attr::find_inline_attr(item.attrs) != attr::ia_none {
+           attr::find_inline_attr(item.attrs) != attr::ia_none { // XXX why is this ia_none?
             traverse_inline_body(cx, blk);
         }
       }
       item_impl(ref generics, _, _, ref ms) => {
         for ms.each |m| {
             if generics.ty_params.len() > 0u ||
                 m.generics.ty_params.len() > 0u ||
-                attr::find_inline_attr(m.attrs) != attr::ia_none
+                attr::find_inline_attr(m.attrs) != attr::ia_none // XXX why is this ia_none?
             {
                 {
                     let cx = &mut *cx; // FIXME(#6269) reborrow @mut to &mut

src/libsyntax/attr.rs

@@ -304,6 +304,9 @@ pub fn find_linkage_metas(attrs: &[ast::attribute]) -> ~[@ast::meta_item] {
 #[deriving(Eq)]
 pub enum inline_attr {
     ia_none,
+    // just write the inlining info to crate metadata, don't hint
+    // LLVM, because that can be too forceful
+    ia_maybe,
     ia_hint,
     ia_always,
     ia_never,
@@ -316,7 +319,9 @@ pub fn find_inline_attr(attrs: &[ast::attribute]) -> inline_attr {
         match attr.node.value.node {
           ast::meta_word(@~"inline") => ia_hint,
           ast::meta_list(@~"inline", ref items) => {
-            if !find_meta_items_by_name(*items, "always").is_empty() {
+            if !find_meta_items_by_name(*items, "maybe").is_empty() {
+                ia_maybe
+            } else if !find_meta_items_by_name(*items, "always").is_empty() {
                 ia_always
             } else if !find_meta_items_by_name(*items, "never").is_empty() {
                 ia_never