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Auto merge of #38117 - michaelwoerister:hidden-symbols, r=alexcrichton
Improve symbol visibility handling for dynamic libraries. This will hopefully fix issue #37530 and maybe also #32887. I'm relying on @m4b to post some numbers on how awesome the improvement for cdylibs is `:)` cc @rust-lang/compiler @rust-lang/tools @cuviper @froydnj r? @alexcrichton
2 parents 06b8d1d + 8ecdc4e commit daf8c1d

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22 files changed

+623
-243
lines changed

22 files changed

+623
-243
lines changed

‎src/librustc/middle/cstore.rs

Lines changed: 5 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -328,8 +328,9 @@ pub trait CrateStore<'tcx> {
328328
fn crate_hash(&self, cnum: CrateNum) -> Svh;
329329
fn crate_disambiguator(&self, cnum: CrateNum) -> Symbol;
330330
fn plugin_registrar_fn(&self, cnum: CrateNum) -> Option<DefId>;
331+
fn derive_registrar_fn(&self, cnum: CrateNum) -> Option<DefId>;
331332
fn native_libraries(&self, cnum: CrateNum) -> Vec<NativeLibrary>;
332-
fn reachable_ids(&self, cnum: CrateNum) -> Vec<DefId>;
333+
fn exported_symbols(&self, cnum: CrateNum) -> Vec<DefId>;
333334
fn is_no_builtins(&self, cnum: CrateNum) -> bool;
334335

335336
// resolve
@@ -491,9 +492,11 @@ impl<'tcx> CrateStore<'tcx> for DummyCrateStore {
491492
-> Symbol { bug!("crate_disambiguator") }
492493
fn plugin_registrar_fn(&self, cnum: CrateNum) -> Option<DefId>
493494
{ bug!("plugin_registrar_fn") }
495+
fn derive_registrar_fn(&self, cnum: CrateNum) -> Option<DefId>
496+
{ bug!("derive_registrar_fn") }
494497
fn native_libraries(&self, cnum: CrateNum) -> Vec<NativeLibrary>
495498
{ bug!("native_libraries") }
496-
fn reachable_ids(&self, cnum: CrateNum) -> Vec<DefId> { bug!("reachable_ids") }
499+
fn exported_symbols(&self, cnum: CrateNum) -> Vec<DefId> { bug!("exported_symbols") }
497500
fn is_no_builtins(&self, cnum: CrateNum) -> bool { bug!("is_no_builtins") }
498501

499502
// resolve

‎src/librustc_llvm/ffi.rs

Lines changed: 11 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -64,6 +64,15 @@ pub enum Linkage {
6464
CommonLinkage = 10,
6565
}
6666

67+
// LLVMRustVisibility
68+
#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
69+
#[repr(C)]
70+
pub enum Visibility {
71+
Default = 0,
72+
Hidden = 1,
73+
Protected = 2,
74+
}
75+
6776
/// LLVMDiagnosticSeverity
6877
#[derive(Copy, Clone, Debug)]
6978
#[repr(C)]
@@ -399,13 +408,6 @@ pub type OperandBundleDefRef = *mut OperandBundleDef_opaque;
399408
pub type DiagnosticHandler = unsafe extern "C" fn(DiagnosticInfoRef, *mut c_void);
400409
pub type InlineAsmDiagHandler = unsafe extern "C" fn(SMDiagnosticRef, *const c_void, c_uint);
401410

402-
/// LLVMVisibility
403-
#[repr(C)]
404-
pub enum Visibility {
405-
Default,
406-
Hidden,
407-
Protected,
408-
}
409411

410412
pub mod debuginfo {
411413
use super::MetadataRef;
@@ -655,7 +657,8 @@ extern "C" {
655657
pub fn LLVMRustSetLinkage(Global: ValueRef, RustLinkage: Linkage);
656658
pub fn LLVMGetSection(Global: ValueRef) -> *const c_char;
657659
pub fn LLVMSetSection(Global: ValueRef, Section: *const c_char);
658-
pub fn LLVMSetVisibility(Global: ValueRef, Viz: Visibility);
660+
pub fn LLVMRustGetVisibility(Global: ValueRef) -> Visibility;
661+
pub fn LLVMRustSetVisibility(Global: ValueRef, Viz: Visibility);
659662
pub fn LLVMGetAlignment(Global: ValueRef) -> c_uint;
660663
pub fn LLVMSetAlignment(Global: ValueRef, Bytes: c_uint);
661664
pub fn LLVMSetDLLStorageClass(V: ValueRef, C: DLLStorageClass);

‎src/librustc_metadata/cstore_impl.rs

Lines changed: 10 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -306,14 +306,22 @@ impl<'tcx> CrateStore<'tcx> for cstore::CStore {
306306
})
307307
}
308308

309+
fn derive_registrar_fn(&self, cnum: CrateNum) -> Option<DefId>
310+
{
311+
self.get_crate_data(cnum).root.macro_derive_registrar.map(|index| DefId {
312+
krate: cnum,
313+
index: index
314+
})
315+
}
316+
309317
fn native_libraries(&self, cnum: CrateNum) -> Vec<NativeLibrary>
310318
{
311319
self.get_crate_data(cnum).get_native_libraries()
312320
}
313321

314-
fn reachable_ids(&self, cnum: CrateNum) -> Vec<DefId>
322+
fn exported_symbols(&self, cnum: CrateNum) -> Vec<DefId>
315323
{
316-
self.get_crate_data(cnum).get_reachable_ids()
324+
self.get_crate_data(cnum).get_exported_symbols()
317325
}
318326

319327
fn is_no_builtins(&self, cnum: CrateNum) -> bool {

‎src/librustc_metadata/decoder.rs

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1038,8 +1038,8 @@ impl<'a, 'tcx> CrateMetadata {
10381038
arg_names.decode(self).collect()
10391039
}
10401040

1041-
pub fn get_reachable_ids(&self) -> Vec<DefId> {
1042-
self.root.reachable_ids.decode(self).map(|index| self.local_def_id(index)).collect()
1041+
pub fn get_exported_symbols(&self) -> Vec<DefId> {
1042+
self.root.exported_symbols.decode(self).map(|index| self.local_def_id(index)).collect()
10431043
}
10441044

10451045
pub fn get_macro(&self, id: DefIndex) -> (ast::Name, MacroDef) {

‎src/librustc_metadata/encoder.rs

Lines changed: 12 additions & 12 deletions
Original file line numberDiff line numberDiff line change
@@ -50,7 +50,7 @@ pub struct EncodeContext<'a, 'tcx: 'a> {
5050
reexports: &'a def::ExportMap,
5151
link_meta: &'a LinkMeta,
5252
cstore: &'a cstore::CStore,
53-
reachable: &'a NodeSet,
53+
exported_symbols: &'a NodeSet,
5454

5555
lazy_state: LazyState,
5656
type_shorthands: FxHashMap<Ty<'tcx>, usize>,
@@ -1223,16 +1223,16 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
12231223
self.lazy_seq(all_impls)
12241224
}
12251225

1226-
// Encodes all reachable symbols in this crate into the metadata.
1226+
// Encodes all symbols exported from this crate into the metadata.
12271227
//
12281228
// This pass is seeded off the reachability list calculated in the
12291229
// middle::reachable module but filters out items that either don't have a
12301230
// symbol associated with them (they weren't translated) or if they're an FFI
12311231
// definition (as that's not defined in this crate).
1232-
fn encode_reachable(&mut self) -> LazySeq<DefIndex> {
1233-
let reachable = self.reachable;
1232+
fn encode_exported_symbols(&mut self) -> LazySeq<DefIndex> {
1233+
let exported_symbols = self.exported_symbols;
12341234
let tcx = self.tcx;
1235-
self.lazy_seq(reachable.iter().map(|&id| tcx.map.local_def_id(id).index))
1235+
self.lazy_seq(exported_symbols.iter().map(|&id| tcx.map.local_def_id(id).index))
12361236
}
12371237

12381238
fn encode_dylib_dependency_formats(&mut self) -> LazySeq<Option<LinkagePreference>> {
@@ -1278,10 +1278,10 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
12781278
let impls = self.encode_impls();
12791279
let impl_bytes = self.position() - i;
12801280

1281-
// Encode reachability info.
1281+
// Encode exported symbols info.
12821282
i = self.position();
1283-
let reachable_ids = self.encode_reachable();
1284-
let reachable_bytes = self.position() - i;
1283+
let exported_symbols = self.encode_exported_symbols();
1284+
let exported_symbols_bytes = self.position() - i;
12851285

12861286
// Encode and index the items.
12871287
i = self.position();
@@ -1319,7 +1319,7 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
13191319
native_libraries: native_libraries,
13201320
codemap: codemap,
13211321
impls: impls,
1322-
reachable_ids: reachable_ids,
1322+
exported_symbols: exported_symbols,
13231323
index: index,
13241324
});
13251325

@@ -1339,7 +1339,7 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
13391339
println!(" native bytes: {}", native_lib_bytes);
13401340
println!(" codemap bytes: {}", codemap_bytes);
13411341
println!(" impl bytes: {}", impl_bytes);
1342-
println!(" reachable bytes: {}", reachable_bytes);
1342+
println!(" exp. symbols bytes: {}", exported_symbols_bytes);
13431343
println!(" item bytes: {}", item_bytes);
13441344
println!(" index bytes: {}", index_bytes);
13451345
println!(" zero bytes: {}", zero_bytes);
@@ -1377,7 +1377,7 @@ pub fn encode_metadata<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
13771377
cstore: &cstore::CStore,
13781378
reexports: &def::ExportMap,
13791379
link_meta: &LinkMeta,
1380-
reachable: &NodeSet)
1380+
exported_symbols: &NodeSet)
13811381
-> Vec<u8> {
13821382
let mut cursor = Cursor::new(vec![]);
13831383
cursor.write_all(METADATA_HEADER).unwrap();
@@ -1392,7 +1392,7 @@ pub fn encode_metadata<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
13921392
reexports: reexports,
13931393
link_meta: link_meta,
13941394
cstore: cstore,
1395-
reachable: reachable,
1395+
exported_symbols: exported_symbols,
13961396
lazy_state: LazyState::NoNode,
13971397
type_shorthands: Default::default(),
13981398
predicate_shorthands: Default::default(),

‎src/librustc_metadata/schema.rs

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -180,7 +180,7 @@ pub struct CrateRoot {
180180
pub native_libraries: LazySeq<NativeLibrary>,
181181
pub codemap: LazySeq<syntax_pos::FileMap>,
182182
pub impls: LazySeq<TraitImpls>,
183-
pub reachable_ids: LazySeq<DefIndex>,
183+
pub exported_symbols: LazySeq<DefIndex>,
184184
pub index: LazySeq<index::Index>,
185185
}
186186

‎src/librustc_trans/back/linker.rs

Lines changed: 43 additions & 56 deletions
Original file line numberDiff line numberDiff line change
@@ -17,11 +17,11 @@ use std::path::{Path, PathBuf};
1717
use std::process::Command;
1818

1919
use context::SharedCrateContext;
20-
use monomorphize::Instance;
2120

2221
use back::archive;
22+
use back::symbol_export::{self, ExportedSymbols};
2323
use middle::dependency_format::Linkage;
24-
use rustc::hir::def_id::CrateNum;
24+
use rustc::hir::def_id::{LOCAL_CRATE, CrateNum};
2525
use session::Session;
2626
use session::config::CrateType;
2727
use session::config;
@@ -34,10 +34,10 @@ pub struct LinkerInfo {
3434

3535
impl<'a, 'tcx> LinkerInfo {
3636
pub fn new(scx: &SharedCrateContext<'a, 'tcx>,
37-
reachable: &[String]) -> LinkerInfo {
37+
exports: &ExportedSymbols) -> LinkerInfo {
3838
LinkerInfo {
3939
exports: scx.sess().crate_types.borrow().iter().map(|&c| {
40-
(c, exported_symbols(scx, reachable, c))
40+
(c, exported_symbols(scx, exports, c))
4141
}).collect(),
4242
}
4343
}
@@ -253,46 +253,47 @@ impl<'a> Linker for GnuLinker<'a> {
253253
let mut arg = OsString::new();
254254
let path = tmpdir.join("list");
255255

256-
if self.sess.target.target.options.is_like_solaris {
256+
debug!("EXPORTED SYMBOLS:");
257+
258+
if self.sess.target.target.options.is_like_osx {
259+
// Write a plain, newline-separated list of symbols
257260
let res = (|| -> io::Result<()> {
258261
let mut f = BufWriter::new(File::create(&path)?);
259-
writeln!(f, "{{\n global:")?;
260262
for sym in self.info.exports[&crate_type].iter() {
261-
writeln!(f, " {};", sym)?;
263+
debug!(" _{}", sym);
264+
writeln!(f, "_{}", sym)?;
262265
}
263-
writeln!(f, "\n local:\n *;\n}};")?;
264266
Ok(())
265267
})();
266268
if let Err(e) = res {
267-
self.sess.fatal(&format!("failed to write version script: {}", e));
269+
self.sess.fatal(&format!("failed to write lib.def file: {}", e));
268270
}
269-
270-
arg.push("-Wl,-M,");
271-
arg.push(&path);
272271
} else {
273-
let prefix = if self.sess.target.target.options.is_like_osx {
274-
"_"
275-
} else {
276-
""
277-
};
272+
// Write an LD version script
278273
let res = (|| -> io::Result<()> {
279274
let mut f = BufWriter::new(File::create(&path)?);
275+
writeln!(f, "{{\n global:")?;
280276
for sym in self.info.exports[&crate_type].iter() {
281-
writeln!(f, "{}{}", prefix, sym)?;
277+
debug!(" {};", sym);
278+
writeln!(f, " {};", sym)?;
282279
}
280+
writeln!(f, "\n local:\n *;\n}};")?;
283281
Ok(())
284282
})();
285283
if let Err(e) = res {
286-
self.sess.fatal(&format!("failed to write lib.def file: {}", e));
287-
}
288-
if self.sess.target.target.options.is_like_osx {
289-
arg.push("-Wl,-exported_symbols_list,");
290-
} else {
291-
arg.push("-Wl,--retain-symbols-file=");
284+
self.sess.fatal(&format!("failed to write version script: {}", e));
292285
}
293-
arg.push(&path);
294286
}
295287

288+
if self.sess.target.target.options.is_like_osx {
289+
arg.push("-Wl,-exported_symbols_list,");
290+
} else if self.sess.target.target.options.is_like_solaris {
291+
arg.push("-Wl,-M,");
292+
} else {
293+
arg.push("-Wl,--version-script=");
294+
}
295+
296+
arg.push(&path);
296297
self.cmd.arg(arg);
297298
}
298299

@@ -473,43 +474,29 @@ impl<'a> Linker for MsvcLinker<'a> {
473474
}
474475

475476
fn exported_symbols(scx: &SharedCrateContext,
476-
reachable: &[String],
477+
exported_symbols: &ExportedSymbols,
477478
crate_type: CrateType)
478479
-> Vec<String> {
479-
// See explanation in GnuLinker::export_symbols, for
480-
// why we don't ever need dylib symbols on non-MSVC.
481-
if crate_type == CrateType::CrateTypeDylib ||
482-
crate_type == CrateType::CrateTypeProcMacro {
483-
if !scx.sess().target.target.options.is_like_msvc {
484-
return vec![];
485-
}
486-
}
480+
let export_threshold = symbol_export::crate_export_threshold(crate_type);
487481

488-
let mut symbols = reachable.to_vec();
482+
let mut symbols = Vec::new();
483+
exported_symbols.for_each_exported_symbol(LOCAL_CRATE, export_threshold, |name, _| {
484+
symbols.push(name.to_owned());
485+
});
489486

490-
// If we're producing anything other than a dylib then the `reachable` array
491-
// above is the exhaustive set of symbols we should be exporting.
492-
//
493-
// For dylibs, however, we need to take a look at how all upstream crates
494-
// are linked into this dynamic library. For all statically linked
495-
// libraries we take all their reachable symbols and emit them as well.
496-
if crate_type != CrateType::CrateTypeDylib {
497-
return symbols
498-
}
499-
500-
let cstore = &scx.sess().cstore;
501487
let formats = scx.sess().dependency_formats.borrow();
502488
let deps = formats[&crate_type].iter();
503-
symbols.extend(deps.enumerate().filter_map(|(i, f)| {
504-
if *f == Linkage::Static {
505-
Some(CrateNum::new(i + 1))
506-
} else {
507-
None
489+
490+
for (index, dep_format) in deps.enumerate() {
491+
let cnum = CrateNum::new(index + 1);
492+
// For each dependency that we are linking to statically ...
493+
if *dep_format == Linkage::Static {
494+
// ... we add its symbol list to our export list.
495+
exported_symbols.for_each_exported_symbol(cnum, export_threshold, |name, _| {
496+
symbols.push(name.to_owned());
497+
})
508498
}
509-
}).flat_map(|cnum| {
510-
cstore.reachable_ids(cnum)
511-
}).map(|did| -> String {
512-
Instance::mono(scx, did).symbol_name(scx)
513-
}));
499+
}
500+
514501
symbols
515502
}

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