Refactor symbol export list generation.

src/librustc/middle/cstore.rs

@@ -328,6 +328,7 @@ pub trait CrateStore<'tcx> {
     fn crate_hash(&self, cnum: CrateNum) -> Svh;
     fn crate_disambiguator(&self, cnum: CrateNum) -> Symbol;
     fn plugin_registrar_fn(&self, cnum: CrateNum) -> Option<DefId>;
+    fn derive_registrar_fn(&self, cnum: CrateNum) -> Option<DefId>;
     fn native_libraries(&self, cnum: CrateNum) -> Vec<NativeLibrary>;
     fn exported_symbols(&self, cnum: CrateNum) -> Vec<DefId>;
     fn is_no_builtins(&self, cnum: CrateNum) -> bool;
@@ -491,6 +492,8 @@ impl<'tcx> CrateStore<'tcx> for DummyCrateStore {
                            -> Symbol { bug!("crate_disambiguator") }
     fn plugin_registrar_fn(&self, cnum: CrateNum) -> Option<DefId>
         { bug!("plugin_registrar_fn") }
+    fn derive_registrar_fn(&self, cnum: CrateNum) -> Option<DefId>
+        { bug!("derive_registrar_fn") }
     fn native_libraries(&self, cnum: CrateNum) -> Vec<NativeLibrary>
         { bug!("native_libraries") }
     fn exported_symbols(&self, cnum: CrateNum) -> Vec<DefId> { bug!("exported_symbols") }

src/librustc_metadata/cstore_impl.rs

@@ -306,6 +306,14 @@ impl<'tcx> CrateStore<'tcx> for cstore::CStore {
         })
     }
 
+    fn derive_registrar_fn(&self, cnum: CrateNum) -> Option<DefId>
+    {
+        self.get_crate_data(cnum).root.macro_derive_registrar.map(|index| DefId {
+            krate: cnum,
+            index: index
+        })
+    }
+
     fn native_libraries(&self, cnum: CrateNum) -> Vec<NativeLibrary>
     {
         self.get_crate_data(cnum).get_native_libraries()

src/librustc_trans/back/linker.rs

@@ -17,11 +17,11 @@ use std::path::{Path, PathBuf};
 use std::process::Command;
 
 use context::SharedCrateContext;
-use monomorphize::Instance;
 
 use back::archive;
+use back::symbol_export::{self, ExportedSymbols};
 use middle::dependency_format::Linkage;
-use rustc::hir::def_id::CrateNum;
+use rustc::hir::def_id::{LOCAL_CRATE, CrateNum};
 use session::Session;
 use session::config::CrateType;
 use session::config;
@@ -34,7 +34,7 @@ pub struct LinkerInfo {
 
 impl<'a, 'tcx> LinkerInfo {
     pub fn new(scx: &SharedCrateContext<'a, 'tcx>,
-               exports: &[String]) -> LinkerInfo {
+               exports: &ExportedSymbols) -> LinkerInfo {
         LinkerInfo {
             exports: scx.sess().crate_types.borrow().iter().map(|&c| {
                 (c, exported_symbols(scx, exports, c))
@@ -473,43 +473,29 @@ impl<'a> Linker for MsvcLinker<'a> {
 }
 
 fn exported_symbols(scx: &SharedCrateContext,
-                    exported_symbols: &[String],
+                    exported_symbols: &ExportedSymbols,
                     crate_type: CrateType)
                     -> Vec<String> {
-    // See explanation in GnuLinker::export_symbols, for
-    // why we don't ever need dylib symbols on non-MSVC.
-    if crate_type == CrateType::CrateTypeDylib ||
-       crate_type == CrateType::CrateTypeProcMacro {
-        if !scx.sess().target.target.options.is_like_msvc {
-            return vec![];
-        }
-    }
-
-    let mut symbols = exported_symbols.to_vec();
+    let export_threshold = symbol_export::crate_export_threshold(crate_type);
 
-    // If we're producing anything other than a dylib then the `reachable` array
-    // above is the exhaustive set of symbols we should be exporting.
-    //
-    // For dylibs, however, we need to take a look at how all upstream crates
-    // are linked into this dynamic library. For all statically linked
-    // libraries we take all their reachable symbols and emit them as well.
-    if crate_type != CrateType::CrateTypeDylib {
-        return symbols
-    }
+    let mut symbols = Vec::new();
+    exported_symbols.for_each_exported_symbol(LOCAL_CRATE, export_threshold, |name, _| {
+        symbols.push(name.to_owned());
+    });
 
-    let cstore = &scx.sess().cstore;
     let formats = scx.sess().dependency_formats.borrow();
     let deps = formats[&crate_type].iter();
-    symbols.extend(deps.enumerate().filter_map(|(i, f)| {
-        if *f == Linkage::Static {
-            Some(CrateNum::new(i + 1))
-        } else {
-            None
+
+    for (index, dep_format) in deps.enumerate() {
+        let cnum = CrateNum::new(index + 1);
+        // For each dependency that we are linking to statically ...
+        if *dep_format == Linkage::Static {
+            // ... we add its symbol list to our export list.
+            exported_symbols.for_each_exported_symbol(cnum, export_threshold, |name, _| {
+                symbols.push(name.to_owned());
+            })
         }
-    }).flat_map(|cnum| {
-        cstore.exported_symbols(cnum)
-    }).map(|did| -> String {
-        Instance::mono(scx, did).symbol_name(scx)
-    }));
+    }
+
     symbols
 }

src/librustc_trans/back/lto.rs

@@ -8,14 +8,16 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use super::link;
-use super::write;
+use back::link;
+use back::write;
+use back::symbol_export::{self, ExportedSymbols};
 use rustc::session::{self, config};
 use llvm;
 use llvm::archive_ro::ArchiveRO;
 use llvm::{ModuleRef, TargetMachineRef, True, False};
 use rustc::util::common::time;
 use rustc::util::common::path2cstr;
+use rustc::hir::def_id::LOCAL_CRATE;
 use back::write::{ModuleConfig, with_llvm_pmb};
 
 use libc;
@@ -24,8 +26,23 @@ use flate;
 use std::ffi::CString;
 use std::path::Path;
 
-pub fn run(sess: &session::Session, llmod: ModuleRef,
-           tm: TargetMachineRef, exported_symbols: &[String],
+pub fn crate_type_allows_lto(crate_type: config::CrateType) -> bool {
+    match crate_type {
+        config::CrateTypeExecutable |
+        config::CrateTypeStaticlib  |
+        config::CrateTypeCdylib     => true,
+
+        config::CrateTypeDylib     |
+        config::CrateTypeRlib      |
+        config::CrateTypeMetadata  |
+        config::CrateTypeProcMacro => false,
+    }
+}
+
+pub fn run(sess: &session::Session,
+           llmod: ModuleRef,
+           tm: TargetMachineRef,
+           exported_symbols: &ExportedSymbols,
            config: &ModuleConfig,
            temp_no_opt_bc_filename: &Path) {
     if sess.opts.cg.prefer_dynamic {
@@ -38,17 +55,31 @@ pub fn run(sess: &session::Session, llmod: ModuleRef,
 
     // Make sure we actually can run LTO
     for crate_type in sess.crate_types.borrow().iter() {
-        match *crate_type {
-            config::CrateTypeExecutable |
-            config::CrateTypeCdylib |
-            config::CrateTypeStaticlib => {}
-            _ => {
-                sess.fatal("lto can only be run for executables and \
+        if !crate_type_allows_lto(*crate_type) {
+            sess.fatal("lto can only be run for executables and \
                             static library outputs");
-            }
         }
     }
 
+    let export_threshold =
+        symbol_export::crates_export_threshold(&sess.crate_types.borrow()[..]);
+
+    let symbol_filter = &|&(ref name, level): &(String, _)| {
+        if symbol_export::is_below_threshold(level, export_threshold) {
+            let mut bytes = Vec::with_capacity(name.len() + 1);
+            bytes.extend(name.bytes());
+            Some(CString::new(bytes).unwrap())
+        } else {
+            None
+        }
+    };
+
+    let mut symbol_white_list: Vec<CString> = exported_symbols
+        .exported_symbols(LOCAL_CRATE)
+        .iter()
+        .filter_map(symbol_filter)
+        .collect();
+
     // For each of our upstream dependencies, find the corresponding rlib and
     // load the bitcode from the archive. Then merge it into the current LLVM
     // module that we've got.
@@ -58,6 +89,11 @@ pub fn run(sess: &session::Session, llmod: ModuleRef,
             return;
         }
 
+        symbol_white_list.extend(
+            exported_symbols.exported_symbols(cnum)
+                            .iter()
+                            .filter_map(symbol_filter));
+
         let archive = ArchiveRO::open(&path).expect("wanted an rlib");
         let bytecodes = archive.iter().filter_map(|child| {
             child.ok().and_then(|c| c.name().map(|name| (name, c)))
@@ -119,10 +155,9 @@ pub fn run(sess: &session::Session, llmod: ModuleRef,
     });
 
     // Internalize everything but the exported symbols of the current module
-    let cstrs: Vec<CString> = exported_symbols.iter().map(|s| {
-        CString::new(s.clone()).unwrap()
-    }).collect();
-    let arr: Vec<*const libc::c_char> = cstrs.iter().map(|c| c.as_ptr()).collect();
+    let arr: Vec<*const libc::c_char> = symbol_white_list.iter()
+                                                         .map(|c| c.as_ptr())
+                                                         .collect();
     let ptr = arr.as_ptr();
     unsafe {
         llvm::LLVMRustRunRestrictionPass(llmod,