syntax: Conditionally deriving(Hash) with Writers

If #[feature(default_type_parameters)] is enabled for a crate, then
deriving(Hash) will expand with Hash<W: Writer> instead of Hash<SipState> so
more hash algorithms can be used.

Author: alexcrichton

src/librustc/driver/driver.rs

@@ -224,8 +224,12 @@ pub fn phase_2_configure_and_expand(sess: Session,
                  front::config::strip_unconfigured_items(krate));
 
     krate = time(time_passes, "expansion", krate, |krate| {
+        let cfg = syntax::ext::expand::ExpansionConfig {
+            loader: loader,
+            deriving_hash_type_parameter: sess.features.default_type_params.get()
+        };
         syntax::ext::expand::expand_crate(sess.parse_sess,
-                                          loader,
+                                          cfg,
                                           krate)
     });
     // dump the syntax-time crates

src/librustc/front/test.rs

@@ -28,6 +28,7 @@ use syntax::attr;
 use syntax::codemap::{DUMMY_SP, Span, ExpnInfo, NameAndSpan, MacroAttribute};
 use syntax::codemap;
 use syntax::ext::base::ExtCtxt;
+use syntax::ext::expand::ExpansionConfig;
 use syntax::fold::Folder;
 use syntax::fold;
 use syntax::opt_vec;
@@ -165,7 +166,11 @@ fn generate_test_harness(sess: session::Session, krate: ast::Crate)
     let loader = &mut Loader::new(sess);
     let mut cx: TestCtxt = TestCtxt {
         sess: sess,
-        ext_cx: ExtCtxt::new(sess.parse_sess, sess.opts.cfg.clone(), loader),
+        ext_cx: ExtCtxt::new(sess.parse_sess, sess.opts.cfg.clone(),
+                             ExpansionConfig {
+                                 loader: loader,
+                                 deriving_hash_type_parameter: false,
+                             }),
         path: RefCell::new(~[]),
         testfns: RefCell::new(~[]),
         is_test_crate: is_test_crate(&krate),

src/librustc/middle/ty.rs

@@ -179,6 +179,13 @@ impl cmp::Eq for intern_key {
     }
 }
 
+#[cfg(stage0)]
+impl Hash for intern_key {
+    fn hash(&self, s: &mut sip::SipState) {
+        unsafe { (*self.sty).hash(s) }
+    }
+}
+#[cfg(not(stage0))]
 impl<W:Writer> Hash<W> for intern_key {
     fn hash(&self, s: &mut W) {
         unsafe { (*self.sty).hash(s) }
@@ -251,6 +258,9 @@ pub struct ctxt_ {
     diag: @syntax::diagnostic::SpanHandler,
     // Specifically use a speedy hash algorithm for this hash map, it's used
     // quite often.
+    #[cfg(stage0)]
+    interner: RefCell<HashMap<intern_key, ~t_box_>>,
+    #[cfg(not(stage0))]
     interner: RefCell<HashMap<intern_key, ~t_box_, ::util::nodemap::FnvHasher>>,
     next_id: Cell<uint>,
     cstore: @metadata::cstore::CStore,
@@ -1081,12 +1091,19 @@ pub fn mk_ctxt(s: session::Session,
                region_maps: middle::region::RegionMaps,
                lang_items: @middle::lang_items::LanguageItems)
             -> ctxt {
-
+    #[cfg(stage0)]
+    fn hasher() -> HashMap<intern_key, ~t_box_> {
+        HashMap::new()
+    }
+    #[cfg(not(stage0))]
+    fn hasher() -> HashMap<intern_key, ~t_box_, ::util::nodemap::FnvHasher> {
+        HashMap::with_hasher(::util::nodemap::FnvHasher)
+    }
     @ctxt_ {
         named_region_map: named_region_map,
         item_variance_map: RefCell::new(DefIdMap::new()),
         diag: s.diagnostic(),
-        interner: RefCell::new(HashMap::with_hasher(::util::nodemap::FnvHasher)),
+        interner: RefCell::new(hasher()),
         next_id: Cell::new(primitives::LAST_PRIMITIVE_ID),
         cstore: s.cstore,
         sess: s,

src/librustc/util/nodemap.rs

@@ -15,37 +15,84 @@ use std::hash::{Hasher, Hash};
 use std::io;
 use syntax::ast;
 
+#[cfg(not(stage0))]
 pub type NodeMap<T> = HashMap<ast::NodeId, T, FnvHasher>;
+#[cfg(not(stage0))]
 pub type DefIdMap<T> = HashMap<ast::DefId, T, FnvHasher>;
+#[cfg(not(stage0))]
 pub type NodeSet = HashSet<ast::NodeId, FnvHasher>;
+#[cfg(not(stage0))]
 pub type DefIdSet = HashSet<ast::DefId, FnvHasher>;
 
 // Hacks to get good names
+#[cfg(not(stage0))]
 pub mod NodeMap {
     use collections::HashMap;
     pub fn new<T>() -> super::NodeMap<T> {
         HashMap::with_hasher(super::FnvHasher)
     }
 }
+#[cfg(not(stage0))]
 pub mod NodeSet {
     use collections::HashSet;
     pub fn new() -> super::NodeSet {
         HashSet::with_hasher(super::FnvHasher)
     }
 }
+#[cfg(not(stage0))]
 pub mod DefIdMap {
     use collections::HashMap;
     pub fn new<T>() -> super::DefIdMap<T> {
         HashMap::with_hasher(super::FnvHasher)
     }
 }
+#[cfg(not(stage0))]
 pub mod DefIdSet {
     use collections::HashSet;
     pub fn new() -> super::DefIdSet {
         HashSet::with_hasher(super::FnvHasher)
     }
 }
 
+#[cfg(stage0)]
+pub type NodeMap<T> = HashMap<ast::NodeId, T>;
+#[cfg(stage0)]
+pub type DefIdMap<T> = HashMap<ast::DefId, T>;
+#[cfg(stage0)]
+pub type NodeSet = HashSet<ast::NodeId>;
+#[cfg(stage0)]
+pub type DefIdSet = HashSet<ast::DefId>;
+
+// Hacks to get good names
+#[cfg(stage0)]
+pub mod NodeMap {
+    use collections::HashMap;
+    pub fn new<T>() -> super::NodeMap<T> {
+        HashMap::new()
+    }
+}
+#[cfg(stage0)]
+pub mod NodeSet {
+    use collections::HashSet;
+    pub fn new() -> super::NodeSet {
+        HashSet::new()
+    }
+}
+#[cfg(stage0)]
+pub mod DefIdMap {
+    use collections::HashMap;
+    pub fn new<T>() -> super::DefIdMap<T> {
+        HashMap::new()
+    }
+}
+#[cfg(stage0)]
+pub mod DefIdSet {
+    use collections::HashSet;
+    pub fn new() -> super::DefIdSet {
+        HashSet::new()
+    }
+}
+
 /// A speedy hash algorithm for node ids and def ids. The hashmap in
 /// libcollections by default uses SipHash which isn't quite as speedy as we
 /// want. In the compiler we're not really worried about DOS attempts, so we
@@ -56,7 +103,7 @@ pub mod DefIdSet {
 #[deriving(Clone)]
 pub struct FnvHasher;
 
-struct FnvState(u64);
+pub struct FnvState(u64);
 
 impl Hasher<FnvState> for FnvHasher {
     fn hash<T: Hash<FnvState>>(&self, t: &T) -> u64 {

src/libsyntax/ext/base.rs

@@ -283,21 +283,21 @@ pub struct ExtCtxt<'a> {
     parse_sess: @parse::ParseSess,
     cfg: ast::CrateConfig,
     backtrace: Option<@ExpnInfo>,
-    loader: &'a mut CrateLoader,
+    ecfg: expand::ExpansionConfig<'a>,
 
     mod_path: Vec<ast::Ident> ,
     trace_mac: bool
 }
 
 impl<'a> ExtCtxt<'a> {
     pub fn new<'a>(parse_sess: @parse::ParseSess, cfg: ast::CrateConfig,
-               loader: &'a mut CrateLoader) -> ExtCtxt<'a> {
+                   ecfg: expand::ExpansionConfig<'a>) -> ExtCtxt<'a> {
         ExtCtxt {
             parse_sess: parse_sess,
             cfg: cfg,
             backtrace: None,
-            loader: loader,
             mod_path: Vec::new(),
+            ecfg: ecfg,
             trace_mac: false
         }
     }

src/libsyntax/ext/deriving/hash.rs

@@ -22,19 +22,31 @@ pub fn expand_deriving_hash(cx: &mut ExtCtxt,
                             item: @Item,
                             push: |@Item|) {
 
+    let (path, generics, args) = if cx.ecfg.deriving_hash_type_parameter {
+        (Path::new_(vec!("std", "hash", "Hash"), None,
+                    vec!(~Literal(Path::new_local("__H"))), true),
+         LifetimeBounds {
+             lifetimes: Vec::new(),
+             bounds: vec!(("__H", vec!(Path::new(vec!("std", "io", "Writer"))))),
+         },
+         Path::new_local("__H"))
+    } else {
+        (Path::new(vec!("std", "hash", "Hash")),
+         LifetimeBounds::empty(),
+         Path::new(vec!("std", "hash", "sip", "SipState")))
+    };
     let hash_trait_def = TraitDef {
         span: span,
         attributes: Vec::new(),
-        path: Path::new(vec!("std", "hash", "Hash")),
+        path: path,
         additional_bounds: Vec::new(),
-        generics: LifetimeBounds::empty(),
+        generics: generics,
         methods: vec!(
             MethodDef {
                 name: "hash",
                 generics: LifetimeBounds::empty(),
                 explicit_self: borrowed_explicit_self(),
-                args: vec!(Ptr(~Literal(Path::new(vec!("std", "hash", "sip", "SipState"))),
-                            Borrowed(None, MutMutable))),
+                args: vec!(Ptr(~Literal(args), Borrowed(None, MutMutable))),
                 ret_ty: nil_ty(),
                 inline: true,
                 const_nonmatching: false,

src/libsyntax/ext/expand.rs

@@ -443,15 +443,15 @@ pub fn expand_view_item(vi: &ast::ViewItem,
 }
 
 fn load_extern_macros(krate: &ast::ViewItem, fld: &mut MacroExpander) {
-    let MacroCrate { lib, cnum } = fld.cx.loader.load_crate(krate);
+    let MacroCrate { lib, cnum } = fld.cx.ecfg.loader.load_crate(krate);
 
     let crate_name = match krate.node {
         ast::ViewItemExternMod(name, _, _) => name,
         _ => unreachable!()
     };
     let name = format!("<{} macros>", token::get_ident(crate_name));
 
-    let exported_macros = fld.cx.loader.get_exported_macros(cnum);
+    let exported_macros = fld.cx.ecfg.loader.get_exported_macros(cnum);
     for source in exported_macros.iter() {
         let item = parse::parse_item_from_source_str(name.clone(),
                                                      (*source).clone(),
@@ -468,7 +468,7 @@ fn load_extern_macros(krate: &ast::ViewItem, fld: &mut MacroExpander) {
     // Make sure the path contains a / or the linker will search for it.
     let path = os::make_absolute(&path);
 
-    let registrar = match fld.cx.loader.get_registrar_symbol(cnum) {
+    let registrar = match fld.cx.ecfg.loader.get_registrar_symbol(cnum) {
         Some(registrar) => registrar,
         None => return
     };
@@ -823,10 +823,15 @@ impl<'a> Folder for MacroExpander<'a> {
     }
 }
 
+pub struct ExpansionConfig<'a> {
+    loader: &'a mut CrateLoader,
+    deriving_hash_type_parameter: bool,
+}
+
 pub fn expand_crate(parse_sess: @parse::ParseSess,
-                    loader: &mut CrateLoader,
+                    cfg: ExpansionConfig,
                     c: Crate) -> Crate {
-    let mut cx = ExtCtxt::new(parse_sess, c.config.clone(), loader);
+    let mut cx = ExtCtxt::new(parse_sess, c.config.clone(), cfg);
     let mut expander = MacroExpander {
         extsbox: syntax_expander_table(),
         cx: &mut cx,
@@ -995,7 +1000,11 @@ mod test {
             Vec::new(),sess);
         // should fail:
         let mut loader = ErrLoader;
-        expand_crate(sess,&mut loader,crate_ast);
+        let cfg = ::syntax::ext::expand::ExpansionConfig {
+            loader: &mut loader,
+            deriving_hash_type_parameter: false,
+        };
+        expand_crate(sess,cfg,crate_ast);
     }
 
     // make sure that macros can leave scope for modules
@@ -1010,7 +1019,11 @@ mod test {
             Vec::new(),sess);
         // should fail:
         let mut loader = ErrLoader;
-        expand_crate(sess,&mut loader,crate_ast);
+        let cfg = ::syntax::ext::expand::ExpansionConfig {
+            loader: &mut loader,
+            deriving_hash_type_parameter: false,
+        };
+        expand_crate(sess,cfg,crate_ast);
     }
 
     // macro_escape modules shouldn't cause macros to leave scope
@@ -1024,7 +1037,11 @@ mod test {
             Vec::new(), sess);
         // should fail:
         let mut loader = ErrLoader;
-        expand_crate(sess, &mut loader, crate_ast);
+        let cfg = ::syntax::ext::expand::ExpansionConfig {
+            loader: &mut loader,
+            deriving_hash_type_parameter: false,
+        };
+        expand_crate(sess, cfg, crate_ast);
     }
 
     #[test] fn test_contains_flatten (){
@@ -1062,7 +1079,11 @@ mod test {
         let (crate_ast,ps) = string_to_crate_and_sess(crate_str);
         // the cfg argument actually does matter, here...
         let mut loader = ErrLoader;
-        expand_crate(ps,&mut loader,crate_ast)
+        let cfg = ::syntax::ext::expand::ExpansionConfig {
+            loader: &mut loader,
+            deriving_hash_type_parameter: false,
+        };
+        expand_crate(ps,cfg,crate_ast)
     }
 
     //fn expand_and_resolve(crate_str: @str) -> ast::crate {

src/libsyntax/lib.rs

@@ -26,7 +26,7 @@ This API is completely unstable and subject to change.
       html_favicon_url = "http://www.rust-lang.org/favicon.ico",
       html_root_url = "http://static.rust-lang.org/doc/master")];
 
-#[feature(macro_rules, globs, managed_boxes)];
+#[feature(macro_rules, globs, managed_boxes, default_type_params)];
 #[allow(unknown_features)];// Note: remove it after a snapshot.
 #[feature(quote)];