Improve handling of dllexport

mk/platform.mk

@@ -277,10 +277,15 @@ $(foreach target,$(CFG_TARGET), \
 # Fun times!
 #
 # [1]: https://msdn.microsoft.com/en-us/library/28d6s79h.aspx
+#
+# FIXME(stage0): remove this macro and the usage below (and the commments above)
+# 	         when a new snapshot is available. Also remove the
+# 	         RUSTFLAGS$(1)_.._T_ variable in mk/target.mk along with
+# 	         CUSTOM_DEPS (as they were only added for this)
 define ADD_RUSTC_LLVM_DEF_TO_MSVC
 ifeq ($$(findstring msvc,$(1)),msvc)
-RUSTFLAGS_rustc_llvm_T_$(1) += -C link-args="-DEF:$(1)/rt/rustc_llvm.def"
-CUSTOM_DEPS_rustc_llvm_T_$(1) += $(1)/rt/rustc_llvm.def
+RUSTFLAGS0_rustc_llvm_T_$(1) += -C link-args="-DEF:$(1)/rt/rustc_llvm.def"
+CUSTOM_DEPS0_rustc_llvm_T_$(1) += $(1)/rt/rustc_llvm.def
 
 $(1)/rt/rustc_llvm.def: $$(S)src/etc/mklldef.py $$(S)src/librustc_llvm/lib.rs
 	$$(CFG_PYTHON) $$^ $$@ rustc_llvm-$$(CFG_FILENAME_EXTRA)

mk/target.mk

@@ -40,7 +40,7 @@ CRATE_FULLDEPS_$(1)_T_$(2)_H_$(3)_$(4) := \
 		  $$(RT_OUTPUT_DIR_$(2))/$$(dep)) \
 		$$(foreach dep,$$(NATIVE_TOOL_DEPS_$(4)_T_$(2)), \
 		  $$(TBIN$(1)_T_$(3)_H_$(3))/$$(dep)) \
-		$$(CUSTOM_DEPS_$(4)_T_$(2))
+		$$(CUSTOM_DEPS$(1)_$(4)_T_$(2))
 endef
 
 $(foreach host,$(CFG_HOST), \
@@ -92,7 +92,7 @@ $$(TLIB$(1)_T_$(2)_H_$(3))/stamp.$(4): \
 		$$(LLVM_LIBDIR_RUSTFLAGS_$(2)) \
 		$$(LLVM_STDCPP_RUSTFLAGS_$(2)) \
 		$$(RUSTFLAGS_$(4)) \
-		$$(RUSTFLAGS_$(4)_T_$(2)) \
+		$$(RUSTFLAGS$(1)_$(4)_T_$(2)) \
 		--out-dir $$(@D) \
 		-C extra-filename=-$$(CFG_FILENAME_EXTRA) \
 		$$<

src/compiletest/procsrv.rs

@@ -26,8 +26,7 @@ fn add_target_env(cmd: &mut Command, lib_path: &str, aux_path: Option<&str>) {
     // Add the new dylib search path var
     let var = DynamicLibrary::envvar();
     let newpath = DynamicLibrary::create_path(&path);
-    let newpath = newpath.to_str().unwrap().to_string();
-    cmd.env(var, &newpath);
+    cmd.env(var, newpath);
 }
 
 pub struct Result {pub status: ExitStatus, pub out: String, pub err: String}

src/doc/reference.md

@@ -1924,10 +1924,16 @@ On an `extern` block, the following attributes are interpreted:
   name and type. This is feature gated and the exact behavior is
   implementation-defined (due to variety of linker invocation syntax).
 - `link` - indicate that a native library should be linked to for the
-  declarations in this block to be linked correctly. `link` supports an optional `kind`
-  key with three possible values: `dylib`, `static`, and `framework`. See [external blocks](#external-blocks) for more about external blocks. Two
+  declarations in this block to be linked correctly. `link` supports an optional
+  `kind` key with three possible values: `dylib`, `static`, and `framework`. See
+  [external blocks](#external-blocks) for more about external blocks. Two
   examples: `#[link(name = "readline")]` and
   `#[link(name = "CoreFoundation", kind = "framework")]`.
+- `linked_from` - indicates what native library this block of FFI items is
+  coming from. This attribute is of the form `#[linked_from = "foo"]` where
+  `foo` is the name of a library in either `#[link]` or a `-l` flag. This
+  attribute is currently required to export symbols from a Rust dynamic library
+  on Windows, and it is feature gated behind the `linked_from` feature.
 
 On declarations inside an `extern` block, the following attributes are
 interpreted:

src/librustc/metadata/common.rs

@@ -205,8 +205,8 @@ pub const tag_plugin_registrar_fn: usize = 0x10b; // top-level only
 pub const tag_method_argument_names: usize = 0x85;
 pub const tag_method_argument_name: usize = 0x86;
 
-pub const tag_reachable_extern_fns: usize = 0x10c; // top-level only
-pub const tag_reachable_extern_fn_id: usize = 0x87;
+pub const tag_reachable_ids: usize = 0x10c; // top-level only
+pub const tag_reachable_id: usize = 0x87;
 
 pub const tag_items_data_item_stability: usize = 0x88;
 

src/librustc/metadata/creader.rs

@@ -20,6 +20,7 @@ use metadata::cstore::{CStore, CrateSource, MetadataBlob};
 use metadata::decoder;
 use metadata::loader;
 use metadata::loader::CratePaths;
+use util::nodemap::FnvHashMap;
 
 use std::cell::RefCell;
 use std::path::PathBuf;
@@ -47,6 +48,7 @@ pub struct LocalCrateReader<'a, 'b:'a> {
 pub struct CrateReader<'a> {
     sess: &'a Session,
     next_crate_num: ast::CrateNum,
+    foreign_item_map: FnvHashMap<String, Vec<ast::NodeId>>,
 }
 
 impl<'a, 'b, 'v> visit::Visitor<'v> for LocalCrateReader<'a, 'b> {
@@ -157,6 +159,7 @@ impl<'a> CrateReader<'a> {
         CrateReader {
             sess: sess,
             next_crate_num: sess.cstore.next_crate_num(),
+            foreign_item_map: FnvHashMap(),
         }
     }
 
@@ -490,6 +493,20 @@ impl<'a> CrateReader<'a> {
             _ => None,
         }
     }
+
+    fn register_statically_included_foreign_items(&mut self) {
+        let libs = self.sess.cstore.get_used_libraries();
+        for (lib, list) in self.foreign_item_map.iter() {
+            let is_static = libs.borrow().iter().any(|&(ref name, kind)| {
+                lib == name && kind == cstore::NativeStatic
+            });
+            if is_static {
+                for id in list {
+                    self.sess.cstore.add_statically_included_foreign_item(*id);
+                }
+            }
+        }
+    }
 }
 
 impl<'a, 'b> LocalCrateReader<'a, 'b> {
@@ -515,6 +532,7 @@ impl<'a, 'b> LocalCrateReader<'a, 'b> {
         for &(ref name, kind) in &self.sess.opts.libs {
             register_native_lib(self.sess, None, name.clone(), kind);
         }
+        self.creader.register_statically_included_foreign_items();
     }
 
     fn process_crate(&self, c: &ast::Crate) {
@@ -541,87 +559,73 @@ impl<'a, 'b> LocalCrateReader<'a, 'b> {
                                                               None,
                                                               i.span,
                                                               PathKind::Crate);
-                        self.ast_map.with_path(i.id, |path|
-                            cmeta.update_local_path(path));
+                        self.ast_map.with_path(i.id, |path| {
+                            cmeta.update_local_path(path)
+                        });
                         self.sess.cstore.add_extern_mod_stmt_cnum(info.id, cnum);
                     }
                     None => ()
                 }
             }
-            ast::ItemForeignMod(ref fm) => {
-                if fm.abi == abi::Rust || fm.abi == abi::RustIntrinsic {
-                    return;
-                }
+            ast::ItemForeignMod(ref fm) => self.process_foreign_mod(i, fm),
+            _ => { }
+        }
+    }
 
-                // First, add all of the custom link_args attributes
-                let link_args = i.attrs.iter()
-                    .filter_map(|at| if at.name() == "link_args" {
-                        Some(at)
-                    } else {
-                        None
-                    })
-                    .collect::<Vec<&ast::Attribute>>();
-                for m in &link_args {
-                    match m.value_str() {
-                        Some(linkarg) => self.sess.cstore.add_used_link_args(&linkarg),
-                        None => { /* fallthrough */ }
-                    }
-                }
+    fn process_foreign_mod(&mut self, i: &ast::Item, fm: &ast::ForeignMod) {
+        if fm.abi == abi::Rust || fm.abi == abi::RustIntrinsic {
+            return;
+        }
 
-                // Next, process all of the #[link(..)]-style arguments
-                let link_args = i.attrs.iter()
-                    .filter_map(|at| if at.name() == "link" {
-                        Some(at)
-                    } else {
-                        None
-                    })
-                    .collect::<Vec<&ast::Attribute>>();
-                for m in &link_args {
-                    match m.meta_item_list() {
-                        Some(items) => {
-                            let kind = items.iter().find(|k| {
-                                k.name() == "kind"
-                            }).and_then(|a| a.value_str());
-                            let kind = match kind {
-                                Some(k) => {
-                                    if k == "static" {
-                                        cstore::NativeStatic
-                                    } else if self.sess.target.target.options.is_like_osx
-                                              && k == "framework" {
-                                        cstore::NativeFramework
-                                    } else if k == "framework" {
-                                        cstore::NativeFramework
-                                    } else if k == "dylib" {
-                                        cstore::NativeUnknown
-                                    } else {
-                                        self.sess.span_err(m.span,
-                                            &format!("unknown kind: `{}`",
-                                                    k));
-                                        cstore::NativeUnknown
-                                    }
-                                }
-                                None => cstore::NativeUnknown
-                            };
-                            let n = items.iter().find(|n| {
-                                n.name() == "name"
-                            }).and_then(|a| a.value_str());
-                            let n = match n {
-                                Some(n) => n,
-                                None => {
-                                    self.sess.span_err(m.span,
-                                        "#[link(...)] specified without \
-                                         `name = \"foo\"`");
-                                    InternedString::new("foo")
-                                }
-                            };
-                            register_native_lib(self.sess, Some(m.span),
-                                                n.to_string(), kind);
-                        }
-                        None => {}
-                    }
-                }
+        // First, add all of the custom #[link_args] attributes
+        for m in i.attrs.iter().filter(|a| a.check_name("link_args")) {
+            if let Some(linkarg) = m.value_str() {
+                self.sess.cstore.add_used_link_args(&linkarg);
             }
-            _ => { }
+        }
+
+        // Next, process all of the #[link(..)]-style arguments
+        for m in i.attrs.iter().filter(|a| a.check_name("link")) {
+            let items = match m.meta_item_list() {
+                Some(item) => item,
+                None => continue,
+            };
+            let kind = items.iter().find(|k| {
+                k.check_name("kind")
+            }).and_then(|a| a.value_str());
+            let kind = match kind.as_ref().map(|s| &s[..]) {
+                Some("static") => cstore::NativeStatic,
+                Some("dylib") => cstore::NativeUnknown,
+                Some("framework") => cstore::NativeFramework,
+                Some(k) => {
+                    self.sess.span_err(m.span, &format!("unknown kind: `{}`", k));
+                    cstore::NativeUnknown
+                }
+                None => cstore::NativeUnknown
+            };
+            let n = items.iter().find(|n| {
+                n.check_name("name")
+            }).and_then(|a| a.value_str());
+            let n = match n {
+                Some(n) => n,
+                None => {
+                    self.sess.span_err(m.span, "#[link(...)] specified without \
+                                                `name = \"foo\"`");
+                    InternedString::new("foo")
+                }
+            };
+            register_native_lib(self.sess, Some(m.span), n.to_string(), kind);
+        }
+
+        // Finally, process the #[linked_from = "..."] attribute
+        for m in i.attrs.iter().filter(|a| a.check_name("linked_from")) {
+            let lib_name = match m.value_str() {
+                Some(name) => name,
+                None => continue,
+            };
+            let list = self.creader.foreign_item_map.entry(lib_name.to_string())
+                                                    .or_insert(Vec::new());
+            list.extend(fm.items.iter().map(|it| it.id));
         }
     }
 }

src/librustc/metadata/csearch.rs

@@ -352,11 +352,11 @@ pub fn get_method_arg_names(cstore: &cstore::CStore, did: ast::DefId)
     decoder::get_method_arg_names(&*cdata, did.node)
 }
 
-pub fn get_reachable_extern_fns(cstore: &cstore::CStore, cnum: ast::CrateNum)
+pub fn get_reachable_ids(cstore: &cstore::CStore, cnum: ast::CrateNum)
     -> Vec<ast::DefId>
 {
     let cdata = cstore.get_crate_data(cnum);
-    decoder::get_reachable_extern_fns(&*cdata)
+    decoder::get_reachable_ids(&*cdata)
 }
 
 pub fn is_typedef(cstore: &cstore::CStore, did: ast::DefId) -> bool {
@@ -400,3 +400,9 @@ pub fn is_default_impl(cstore: &cstore::CStore, impl_did: ast::DefId) -> bool {
     let cdata = cstore.get_crate_data(impl_did.krate);
     decoder::is_default_impl(&*cdata, impl_did.node)
 }
+
+pub fn is_extern_fn(cstore: &cstore::CStore, did: ast::DefId,
+                    tcx: &ty::ctxt) -> bool {
+    let cdata = cstore.get_crate_data(did.krate);
+    decoder::is_extern_fn(&*cdata, did.node, tcx)
+}

src/librustc/metadata/cstore.rs

@@ -20,7 +20,7 @@ pub use self::NativeLibraryKind::*;
 use back::svh::Svh;
 use metadata::{creader, decoder, loader};
 use session::search_paths::PathKind;
-use util::nodemap::{FnvHashMap, NodeMap};
+use util::nodemap::{FnvHashMap, NodeMap, NodeSet};
 
 use std::cell::{RefCell, Ref};
 use std::rc::Rc;
@@ -97,6 +97,7 @@ pub struct CStore {
     used_crate_sources: RefCell<Vec<CrateSource>>,
     used_libraries: RefCell<Vec<(String, NativeLibraryKind)>>,
     used_link_args: RefCell<Vec<String>>,
+    statically_included_foreign_items: RefCell<NodeSet>,
     pub intr: Rc<IdentInterner>,
 }
 
@@ -108,7 +109,8 @@ impl CStore {
             used_crate_sources: RefCell::new(Vec::new()),
             used_libraries: RefCell::new(Vec::new()),
             used_link_args: RefCell::new(Vec::new()),
-            intr: intr
+            intr: intr,
+            statically_included_foreign_items: RefCell::new(NodeSet()),
         }
     }
 
@@ -167,6 +169,7 @@ impl CStore {
         self.used_crate_sources.borrow_mut().clear();
         self.used_libraries.borrow_mut().clear();
         self.used_link_args.borrow_mut().clear();
+        self.statically_included_foreign_items.borrow_mut().clear();
     }
 
     // This method is used when generating the command line to pass through to
@@ -240,6 +243,14 @@ impl CStore {
                                      -> Option<ast::CrateNum> {
         self.extern_mod_crate_map.borrow().get(&emod_id).cloned()
     }
+
+    pub fn add_statically_included_foreign_item(&self, id: ast::NodeId) {
+        self.statically_included_foreign_items.borrow_mut().insert(id);
+    }
+
+    pub fn is_statically_included_foreign_item(&self, id: ast::NodeId) -> bool {
+        self.statically_included_foreign_items.borrow().contains(&id)
+    }
 }
 
 impl crate_metadata {

src/librustc/metadata/decoder.rs

@@ -45,6 +45,7 @@ use std::str;
 use rbml::reader;
 use rbml;
 use serialize::Decodable;
+use syntax::abi;
 use syntax::attr;
 use syntax::parse::token::{IdentInterner, special_idents};
 use syntax::parse::token;
@@ -1418,10 +1419,10 @@ pub fn get_method_arg_names(cdata: Cmd, id: ast::NodeId) -> Vec<String> {
     }
 }
 
-pub fn get_reachable_extern_fns(cdata: Cmd) -> Vec<ast::DefId> {
+pub fn get_reachable_ids(cdata: Cmd) -> Vec<ast::DefId> {
     let items = reader::get_doc(rbml::Doc::new(cdata.data()),
-                                tag_reachable_extern_fns);
-    reader::tagged_docs(items, tag_reachable_extern_fn_id).map(|doc| {
+                                tag_reachable_ids);
+    reader::tagged_docs(items, tag_reachable_id).map(|doc| {
         ast::DefId {
             krate: cdata.cnum,
             node: reader::doc_as_u32(doc),
@@ -1543,3 +1544,21 @@ pub fn get_imported_filemaps(metadata: &[u8]) -> Vec<codemap::FileMap> {
         Decodable::decode(&mut decoder).unwrap()
     }).collect()
 }
+
+pub fn is_extern_fn(cdata: Cmd, id: ast::NodeId, tcx: &ty::ctxt) -> bool {
+    let root_doc = rbml::Doc::new(cdata.data());
+    let items = reader::get_doc(root_doc, tag_items);
+    let item_doc = match maybe_find_item(id, items) {
+        Some(doc) => doc,
+        None => return false,
+    };
+    if let Fn = item_family(item_doc) {
+        let ty::TypeScheme { generics, ty } = get_type(cdata, id, tcx);
+        generics.types.is_empty() && match ty.sty {
+            ty::TyBareFn(_, fn_ty) => fn_ty.abi != abi::Rust,
+            _ => false,
+        }
+    } else {
+        false
+    }
+}