1 // Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 use super::archive::{ArchiveBuilder, ArchiveConfig};
12 use super::linker::Linker;
13 use super::rpath::RPathConfig;
15 use metadata::METADATA_FILENAME;
16 use rustc::session::config::{self, NoDebugInfo, OutputFilenames, Input, OutputType};
17 use rustc::session::filesearch;
18 use rustc::session::search_paths::PathKind;
19 use rustc::session::Session;
20 use rustc::middle::cstore::{self, LinkMeta, NativeLibrary, LibSource, LinkagePreference,
22 use rustc::middle::dependency_format::Linkage;
24 use rustc::util::common::time;
25 use rustc::util::fs::fix_windows_verbatim_for_gcc;
26 use rustc::dep_graph::{DepKind, DepNode};
27 use rustc::hir::def_id::CrateNum;
28 use rustc::hir::svh::Svh;
29 use rustc_back::tempdir::TempDir;
30 use rustc_back::PanicStrategy;
31 use rustc_incremental::IncrementalHashesMap;
32 use context::get_reloc_model;
38 use std::ffi::OsString;
40 use std::io::{self, Read, Write};
42 use std::path::{Path, PathBuf};
43 use std::process::Command;
45 use flate2::Compression;
46 use flate2::write::DeflateEncoder;
51 /// The LLVM module name containing crate-metadata. This includes a `.` on
52 /// purpose, so it cannot clash with the name of a user-defined module.
53 pub const METADATA_MODULE_NAME: &'static str = "crate.metadata";
54 /// The name of the crate-metadata object file the compiler generates. Must
55 /// match up with `METADATA_MODULE_NAME`.
56 pub const METADATA_OBJ_NAME: &'static str = "crate.metadata.o";
58 // same as for metadata above, but for allocator shim
59 pub const ALLOCATOR_MODULE_NAME: &'static str = "crate.allocator";
60 pub const ALLOCATOR_OBJ_NAME: &'static str = "crate.allocator.o";
62 // RLIB LLVM-BYTECODE OBJECT LAYOUT
65 // 0..10 "RUST_OBJECT" encoded in ASCII
66 // 11..14 format version as little-endian u32
67 // 15..22 size in bytes of deflate compressed LLVM bitcode as
69 // 23.. compressed LLVM bitcode
71 // This is the "magic number" expected at the beginning of a LLVM bytecode
73 pub const RLIB_BYTECODE_OBJECT_MAGIC: &'static [u8] = b"RUST_OBJECT";
75 // The version number this compiler will write to bytecode objects in rlibs
76 pub const RLIB_BYTECODE_OBJECT_VERSION: u32 = 1;
78 // The offset in bytes the bytecode object format version number can be found at
79 pub const RLIB_BYTECODE_OBJECT_VERSION_OFFSET: usize = 11;
81 // The offset in bytes the size of the compressed bytecode can be found at in
83 pub const RLIB_BYTECODE_OBJECT_V1_DATASIZE_OFFSET: usize =
84 RLIB_BYTECODE_OBJECT_VERSION_OFFSET + 4;
86 // The offset in bytes the compressed LLVM bytecode can be found at in format
88 pub const RLIB_BYTECODE_OBJECT_V1_DATA_OFFSET: usize =
89 RLIB_BYTECODE_OBJECT_V1_DATASIZE_OFFSET + 8;
92 pub fn find_crate_name(sess: Option<&Session>,
93 attrs: &[ast::Attribute],
94 input: &Input) -> String {
95 let validate = |s: String, span: Option<Span>| {
96 cstore::validate_crate_name(sess, &s, span);
100 // Look in attributes 100% of the time to make sure the attribute is marked
101 // as used. After doing this, however, we still prioritize a crate name from
102 // the command line over one found in the #[crate_name] attribute. If we
103 // find both we ensure that they're the same later on as well.
104 let attr_crate_name = attrs.iter().find(|at| at.check_name("crate_name"))
105 .and_then(|at| at.value_str().map(|s| (at, s)));
107 if let Some(sess) = sess {
108 if let Some(ref s) = sess.opts.crate_name {
109 if let Some((attr, name)) = attr_crate_name {
111 let msg = format!("--crate-name and #[crate_name] are \
112 required to match, but `{}` != `{}`",
114 sess.span_err(attr.span, &msg);
117 return validate(s.clone(), None);
121 if let Some((attr, s)) = attr_crate_name {
122 return validate(s.to_string(), Some(attr.span));
124 if let Input::File(ref path) = *input {
125 if let Some(s) = path.file_stem().and_then(|s| s.to_str()) {
126 if s.starts_with("-") {
127 let msg = format!("crate names cannot start with a `-`, but \
128 `{}` has a leading hyphen", s);
129 if let Some(sess) = sess {
133 return validate(s.replace("-", "_"), None);
138 "rust_out".to_string()
141 pub fn build_link_meta(incremental_hashes_map: &IncrementalHashesMap) -> LinkMeta {
142 let krate_dep_node = &DepNode::new_no_params(DepKind::Krate);
144 crate_hash: Svh::new(incremental_hashes_map[krate_dep_node].to_smaller_hash()),
150 // The third parameter is for env vars, used on windows to set up the
151 // path for MSVC to find its DLLs, and gcc to find its bundled
153 pub fn get_linker(sess: &Session) -> (String, Command, Vec<(OsString, OsString)>) {
154 let envs = vec![("PATH".into(), command_path(sess))];
156 if let Some(ref linker) = sess.opts.cg.linker {
157 (linker.clone(), Command::new(linker), envs)
158 } else if sess.target.target.options.is_like_msvc {
159 let (cmd, envs) = msvc_link_exe_cmd(sess);
160 ("link.exe".to_string(), cmd, envs)
162 let linker = &sess.target.target.options.linker;
163 (linker.clone(), Command::new(&linker), envs)
168 pub fn msvc_link_exe_cmd(sess: &Session) -> (Command, Vec<(OsString, OsString)>) {
169 use gcc::windows_registry;
171 let target = &sess.opts.target_triple;
172 let tool = windows_registry::find_tool(target, "link.exe");
174 if let Some(tool) = tool {
175 let envs = tool.env().to_vec();
176 (tool.to_command(), envs)
178 debug!("Failed to locate linker.");
179 (Command::new("link.exe"), vec![])
184 pub fn msvc_link_exe_cmd(_sess: &Session) -> (Command, Vec<(OsString, OsString)>) {
185 (Command::new("link.exe"), vec![])
188 pub fn get_ar_prog(sess: &Session) -> String {
189 sess.opts.cg.ar.clone().unwrap_or_else(|| {
190 sess.target.target.options.ar.clone()
194 fn command_path(sess: &Session) -> OsString {
195 // The compiler's sysroot often has some bundled tools, so add it to the
196 // PATH for the child.
197 let mut new_path = sess.host_filesearch(PathKind::All)
198 .get_tools_search_paths();
199 if let Some(path) = env::var_os("PATH") {
200 new_path.extend(env::split_paths(&path));
202 env::join_paths(new_path).unwrap()
205 pub fn remove(sess: &Session, path: &Path) {
206 match fs::remove_file(path) {
209 sess.err(&format!("failed to remove {}: {}",
216 /// Perform the linkage portion of the compilation phase. This will generate all
217 /// of the requested outputs for this compilation session.
218 pub fn link_binary(sess: &Session,
219 trans: &CrateTranslation,
220 outputs: &OutputFilenames,
221 crate_name: &str) -> Vec<PathBuf> {
222 let mut out_filenames = Vec::new();
223 for &crate_type in sess.crate_types.borrow().iter() {
224 // Ignore executable crates if we have -Z no-trans, as they will error.
225 if (sess.opts.debugging_opts.no_trans ||
226 !sess.opts.output_types.should_trans()) &&
227 crate_type == config::CrateTypeExecutable {
231 if invalid_output_for_target(sess, crate_type) {
232 bug!("invalid output type `{:?}` for target os `{}`",
233 crate_type, sess.opts.target_triple);
235 let mut out_files = link_binary_output(sess, trans, crate_type, outputs, crate_name);
236 out_filenames.append(&mut out_files);
239 // Remove the temporary object file and metadata if we aren't saving temps
240 if !sess.opts.cg.save_temps {
241 if sess.opts.output_types.should_trans() {
242 for obj in object_filenames(trans, outputs) {
246 remove(sess, &outputs.with_extension(METADATA_OBJ_NAME));
247 if trans.allocator_module.is_some() {
248 remove(sess, &outputs.with_extension(ALLOCATOR_OBJ_NAME));
256 /// Returns default crate type for target
258 /// Default crate type is used when crate type isn't provided neither
259 /// through cmd line arguments nor through crate attributes
261 /// It is CrateTypeExecutable for all platforms but iOS as there is no
262 /// way to run iOS binaries anyway without jailbreaking and
263 /// interaction with Rust code through static library is the only
265 pub fn default_output_for_target(sess: &Session) -> config::CrateType {
266 if !sess.target.target.options.executables {
267 config::CrateTypeStaticlib
269 config::CrateTypeExecutable
273 /// Checks if target supports crate_type as output
274 pub fn invalid_output_for_target(sess: &Session,
275 crate_type: config::CrateType) -> bool {
276 match (sess.target.target.options.dynamic_linking,
277 sess.target.target.options.executables, crate_type) {
278 (false, _, config::CrateTypeCdylib) |
279 (false, _, config::CrateTypeProcMacro) |
280 (false, _, config::CrateTypeDylib) => true,
281 (_, false, config::CrateTypeExecutable) => true,
286 fn is_writeable(p: &Path) -> bool {
289 Ok(m) => !m.permissions().readonly()
293 fn filename_for_metadata(sess: &Session, crate_name: &str, outputs: &OutputFilenames) -> PathBuf {
294 let out_filename = outputs.single_output_file.clone()
297 .join(&format!("lib{}{}.rmeta", crate_name, sess.opts.cg.extra_filename)));
298 check_file_is_writeable(&out_filename, sess);
302 pub fn filename_for_input(sess: &Session,
303 crate_type: config::CrateType,
305 outputs: &OutputFilenames) -> PathBuf {
306 let libname = format!("{}{}", crate_name, sess.opts.cg.extra_filename);
309 config::CrateTypeRlib => {
310 outputs.out_directory.join(&format!("lib{}.rlib", libname))
312 config::CrateTypeCdylib |
313 config::CrateTypeProcMacro |
314 config::CrateTypeDylib => {
315 let (prefix, suffix) = (&sess.target.target.options.dll_prefix,
316 &sess.target.target.options.dll_suffix);
317 outputs.out_directory.join(&format!("{}{}{}", prefix, libname,
320 config::CrateTypeStaticlib => {
321 let (prefix, suffix) = (&sess.target.target.options.staticlib_prefix,
322 &sess.target.target.options.staticlib_suffix);
323 outputs.out_directory.join(&format!("{}{}{}", prefix, libname,
326 config::CrateTypeExecutable => {
327 let suffix = &sess.target.target.options.exe_suffix;
328 let out_filename = outputs.path(OutputType::Exe);
329 if suffix.is_empty() {
330 out_filename.to_path_buf()
332 out_filename.with_extension(&suffix[1..])
338 pub fn each_linked_rlib(sess: &Session,
339 f: &mut FnMut(CrateNum, &Path)) -> Result<(), String> {
340 let crates = sess.cstore.used_crates(LinkagePreference::RequireStatic).into_iter();
341 let fmts = sess.dependency_formats.borrow();
342 let fmts = fmts.get(&config::CrateTypeExecutable)
343 .or_else(|| fmts.get(&config::CrateTypeStaticlib))
344 .or_else(|| fmts.get(&config::CrateTypeCdylib))
345 .or_else(|| fmts.get(&config::CrateTypeProcMacro));
346 let fmts = match fmts {
348 None => return Err(format!("could not find formats for rlibs"))
350 for (cnum, path) in crates {
351 match fmts.get(cnum.as_usize() - 1) {
352 Some(&Linkage::NotLinked) |
353 Some(&Linkage::IncludedFromDylib) => continue,
355 None => return Err(format!("could not find formats for rlibs"))
357 let name = sess.cstore.crate_name(cnum).clone();
358 let path = match path {
359 LibSource::Some(p) => p,
360 LibSource::MetadataOnly => {
361 return Err(format!("could not find rlib for: `{}`, found rmeta (metadata) file",
365 return Err(format!("could not find rlib for: `{}`", name))
373 /// Returns a boolean indicating whether the specified crate should be ignored
376 /// Crates ignored during LTO are not lumped together in the "massive object
377 /// file" that we create and are linked in their normal rlib states. See
378 /// comments below for what crates do not participate in LTO.
380 /// It's unusual for a crate to not participate in LTO. Typically only
381 /// compiler-specific and unstable crates have a reason to not participate in
383 pub fn ignored_for_lto(sess: &Session, cnum: CrateNum) -> bool {
384 // `#![no_builtins]` crates don't participate in LTO because the state
385 // of builtins gets messed up (our crate isn't tagged with no builtins).
386 // Similarly `#![compiler_builtins]` doesn't participate because we want
388 sess.cstore.is_no_builtins(cnum) || sess.cstore.is_compiler_builtins(cnum)
391 fn out_filename(sess: &Session,
392 crate_type: config::CrateType,
393 outputs: &OutputFilenames,
396 let default_filename = filename_for_input(sess, crate_type, crate_name, outputs);
397 let out_filename = outputs.outputs.get(&OutputType::Exe)
398 .and_then(|s| s.to_owned())
399 .or_else(|| outputs.single_output_file.clone())
400 .unwrap_or(default_filename);
402 check_file_is_writeable(&out_filename, sess);
407 // Make sure files are writeable. Mac, FreeBSD, and Windows system linkers
408 // check this already -- however, the Linux linker will happily overwrite a
409 // read-only file. We should be consistent.
410 fn check_file_is_writeable(file: &Path, sess: &Session) {
411 if !is_writeable(file) {
412 sess.fatal(&format!("output file {} is not writeable -- check its \
413 permissions", file.display()));
417 fn link_binary_output(sess: &Session,
418 trans: &CrateTranslation,
419 crate_type: config::CrateType,
420 outputs: &OutputFilenames,
421 crate_name: &str) -> Vec<PathBuf> {
422 let objects = object_filenames(trans, outputs);
424 for file in &objects {
425 check_file_is_writeable(file, sess);
428 let tmpdir = match TempDir::new("rustc") {
429 Ok(tmpdir) => tmpdir,
430 Err(err) => sess.fatal(&format!("couldn't create a temp dir: {}", err)),
433 let mut out_filenames = vec![];
435 if outputs.outputs.contains_key(&OutputType::Metadata) {
436 let out_filename = filename_for_metadata(sess, crate_name, outputs);
437 emit_metadata(sess, trans, &out_filename);
438 out_filenames.push(out_filename);
441 if outputs.outputs.should_trans() {
442 let out_filename = out_filename(sess, crate_type, outputs, crate_name);
444 config::CrateTypeRlib => {
451 tmpdir.path()).build();
453 config::CrateTypeStaticlib => {
462 link_natively(sess, crate_type, &objects, &out_filename, trans,
463 outputs, tmpdir.path());
466 out_filenames.push(out_filename);
469 if sess.opts.cg.save_temps {
470 let _ = tmpdir.into_path();
476 fn object_filenames(trans: &CrateTranslation,
477 outputs: &OutputFilenames)
479 trans.modules.iter().map(|module| {
480 outputs.temp_path(OutputType::Object, Some(&module.name))
484 fn archive_search_paths(sess: &Session) -> Vec<PathBuf> {
485 let mut search = Vec::new();
486 sess.target_filesearch(PathKind::Native).for_each_lib_search_path(|path, _| {
487 search.push(path.to_path_buf());
492 fn archive_config<'a>(sess: &'a Session,
494 input: Option<&Path>) -> ArchiveConfig<'a> {
497 dst: output.to_path_buf(),
498 src: input.map(|p| p.to_path_buf()),
499 lib_search_paths: archive_search_paths(sess),
500 ar_prog: get_ar_prog(sess),
501 command_path: command_path(sess),
505 fn emit_metadata<'a>(sess: &'a Session, trans: &CrateTranslation, out_filename: &Path) {
506 let result = fs::File::create(out_filename).and_then(|mut f| {
507 f.write_all(&trans.metadata.raw_data)
510 if let Err(e) = result {
511 sess.fatal(&format!("failed to write {}: {}", out_filename.display(), e));
522 // An rlib in its current incarnation is essentially a renamed .a file. The
523 // rlib primarily contains the object file of the crate, but it also contains
524 // all of the object files from native libraries. This is done by unzipping
525 // native libraries and inserting all of the contents into this archive.
526 fn link_rlib<'a>(sess: &'a Session,
527 trans: &CrateTranslation,
530 outputs: &OutputFilenames,
532 tmpdir: &Path) -> ArchiveBuilder<'a> {
533 info!("preparing rlib from {:?} to {:?}", objects, out_filename);
534 let mut ab = ArchiveBuilder::new(archive_config(sess, out_filename, None));
540 // Note that in this loop we are ignoring the value of `lib.cfg`. That is,
541 // we may not be configured to actually include a static library if we're
542 // adding it here. That's because later when we consume this rlib we'll
543 // decide whether we actually needed the static library or not.
545 // To do this "correctly" we'd need to keep track of which libraries added
546 // which object files to the archive. We don't do that here, however. The
547 // #[link(cfg(..))] feature is unstable, though, and only intended to get
548 // liblibc working. In that sense the check below just indicates that if
549 // there are any libraries we want to omit object files for at link time we
550 // just exclude all custom object files.
552 // Eventually if we want to stabilize or flesh out the #[link(cfg(..))]
553 // feature then we'll need to figure out how to record what objects were
554 // loaded from the libraries found here and then encode that into the
555 // metadata of the rlib we're generating somehow.
556 for lib in sess.cstore.used_libraries() {
558 NativeLibraryKind::NativeStatic => {}
559 NativeLibraryKind::NativeStaticNobundle |
560 NativeLibraryKind::NativeFramework |
561 NativeLibraryKind::NativeUnknown => continue,
563 ab.add_native_library(&lib.name.as_str());
566 // After adding all files to the archive, we need to update the
567 // symbol table of the archive.
570 // Note that it is important that we add all of our non-object "magical
571 // files" *after* all of the object files in the archive. The reason for
572 // this is as follows:
574 // * When performing LTO, this archive will be modified to remove
575 // objects from above. The reason for this is described below.
577 // * When the system linker looks at an archive, it will attempt to
578 // determine the architecture of the archive in order to see whether its
581 // The algorithm for this detection is: iterate over the files in the
582 // archive. Skip magical SYMDEF names. Interpret the first file as an
583 // object file. Read architecture from the object file.
585 // * As one can probably see, if "metadata" and "foo.bc" were placed
586 // before all of the objects, then the architecture of this archive would
587 // not be correctly inferred once 'foo.o' is removed.
589 // Basically, all this means is that this code should not move above the
592 RlibFlavor::Normal => {
593 // Instead of putting the metadata in an object file section, rlibs
594 // contain the metadata in a separate file. We use a temp directory
595 // here so concurrent builds in the same directory don't try to use
596 // the same filename for metadata (stomping over one another)
597 let metadata = tmpdir.join(METADATA_FILENAME);
598 emit_metadata(sess, trans, &metadata);
599 ab.add_file(&metadata);
601 // For LTO purposes, the bytecode of this library is also inserted
602 // into the archive. If codegen_units > 1, we insert each of the
605 // Note that we make sure that the bytecode filename in the
606 // archive is never exactly 16 bytes long by adding a 16 byte
607 // extension to it. This is to work around a bug in LLDB that
608 // would cause it to crash if the name of a file in an archive
609 // was exactly 16 bytes.
610 let bc_filename = obj.with_extension("bc");
611 let bc_deflated_filename = tmpdir.join({
612 obj.with_extension("bytecode.deflate").file_name().unwrap()
615 let mut bc_data = Vec::new();
616 match fs::File::open(&bc_filename).and_then(|mut f| {
617 f.read_to_end(&mut bc_data)
620 Err(e) => sess.fatal(&format!("failed to read bytecode: {}",
624 let mut bc_data_deflated = Vec::new();
625 DeflateEncoder::new(&mut bc_data_deflated, Compression::Fast)
626 .write_all(&bc_data).unwrap();
628 let mut bc_file_deflated = match fs::File::create(&bc_deflated_filename) {
631 sess.fatal(&format!("failed to create compressed \
632 bytecode file: {}", e))
636 match write_rlib_bytecode_object_v1(&mut bc_file_deflated,
640 sess.fatal(&format!("failed to write compressed \
645 ab.add_file(&bc_deflated_filename);
647 // See the bottom of back::write::run_passes for an explanation
648 // of when we do and don't keep .#module-name#.bc files around.
649 let user_wants_numbered_bitcode =
650 sess.opts.output_types.contains_key(&OutputType::Bitcode) &&
651 sess.opts.cg.codegen_units > 1;
652 if !sess.opts.cg.save_temps && !user_wants_numbered_bitcode {
653 remove(sess, &bc_filename);
657 // After adding all files to the archive, we need to update the
658 // symbol table of the archive. This currently dies on macOS (see
659 // #11162), and isn't necessary there anyway
660 if !sess.target.target.options.is_like_osx {
665 RlibFlavor::StaticlibBase => {
666 if trans.allocator_module.is_some() {
667 ab.add_file(&outputs.with_extension(ALLOCATOR_OBJ_NAME));
675 fn write_rlib_bytecode_object_v1(writer: &mut Write,
676 bc_data_deflated: &[u8]) -> io::Result<()> {
677 let bc_data_deflated_size: u64 = bc_data_deflated.len() as u64;
679 writer.write_all(RLIB_BYTECODE_OBJECT_MAGIC)?;
680 writer.write_all(&[1, 0, 0, 0])?;
682 (bc_data_deflated_size >> 0) as u8,
683 (bc_data_deflated_size >> 8) as u8,
684 (bc_data_deflated_size >> 16) as u8,
685 (bc_data_deflated_size >> 24) as u8,
686 (bc_data_deflated_size >> 32) as u8,
687 (bc_data_deflated_size >> 40) as u8,
688 (bc_data_deflated_size >> 48) as u8,
689 (bc_data_deflated_size >> 56) as u8,
691 writer.write_all(&bc_data_deflated)?;
693 let number_of_bytes_written_so_far =
694 RLIB_BYTECODE_OBJECT_MAGIC.len() + // magic id
695 mem::size_of_val(&RLIB_BYTECODE_OBJECT_VERSION) + // version
696 mem::size_of_val(&bc_data_deflated_size) + // data size field
697 bc_data_deflated_size as usize; // actual data
699 // If the number of bytes written to the object so far is odd, add a
700 // padding byte to make it even. This works around a crash bug in LLDB
701 // (see issue #15950)
702 if number_of_bytes_written_so_far % 2 == 1 {
703 writer.write_all(&[0])?;
709 // Create a static archive
711 // This is essentially the same thing as an rlib, but it also involves adding
712 // all of the upstream crates' objects into the archive. This will slurp in
713 // all of the native libraries of upstream dependencies as well.
715 // Additionally, there's no way for us to link dynamic libraries, so we warn
716 // about all dynamic library dependencies that they're not linked in.
718 // There's no need to include metadata in a static archive, so ensure to not
719 // link in the metadata object file (and also don't prepare the archive with a
721 fn link_staticlib(sess: &Session,
722 trans: &CrateTranslation,
723 outputs: &OutputFilenames,
727 let mut ab = link_rlib(sess,
729 RlibFlavor::StaticlibBase,
734 let mut all_native_libs = vec![];
736 let res = each_linked_rlib(sess, &mut |cnum, path| {
737 let name = sess.cstore.crate_name(cnum);
738 let native_libs = sess.cstore.native_libraries(cnum);
740 // Here when we include the rlib into our staticlib we need to make a
741 // decision whether to include the extra object files along the way.
742 // These extra object files come from statically included native
743 // libraries, but they may be cfg'd away with #[link(cfg(..))].
745 // This unstable feature, though, only needs liblibc to work. The only
746 // use case there is where musl is statically included in liblibc.rlib,
747 // so if we don't want the included version we just need to skip it. As
748 // a result the logic here is that if *any* linked library is cfg'd away
749 // we just skip all object files.
751 // Clearly this is not sufficient for a general purpose feature, and
752 // we'd want to read from the library's metadata to determine which
753 // object files come from where and selectively skip them.
754 let skip_object_files = native_libs.iter().any(|lib| {
755 lib.kind == NativeLibraryKind::NativeStatic && !relevant_lib(sess, lib)
759 sess.lto() && !ignored_for_lto(sess, cnum),
760 skip_object_files).unwrap();
762 all_native_libs.extend(sess.cstore.native_libraries(cnum));
764 if let Err(e) = res {
771 if !all_native_libs.is_empty() {
772 sess.note_without_error("link against the following native artifacts when linking against \
773 this static library");
774 sess.note_without_error("the order and any duplication can be significant on some \
775 platforms, and so may need to be preserved");
778 for lib in all_native_libs.iter().filter(|l| relevant_lib(sess, l)) {
779 let name = match lib.kind {
780 NativeLibraryKind::NativeStaticNobundle |
781 NativeLibraryKind::NativeUnknown => "library",
782 NativeLibraryKind::NativeFramework => "framework",
783 // These are included, no need to print them
784 NativeLibraryKind::NativeStatic => continue,
786 sess.note_without_error(&format!("{}: {}", name, lib.name));
790 // Create a dynamic library or executable
792 // This will invoke the system linker/cc to create the resulting file. This
793 // links to all upstream files as well.
794 fn link_natively(sess: &Session,
795 crate_type: config::CrateType,
798 trans: &CrateTranslation,
799 outputs: &OutputFilenames,
801 info!("preparing {:?} from {:?} to {:?}", crate_type, objects, out_filename);
802 let flavor = sess.linker_flavor();
804 // The invocations of cc share some flags across platforms
805 let (pname, mut cmd, envs) = get_linker(sess);
806 // This will set PATH on windows
809 let root = sess.target_filesearch(PathKind::Native).get_lib_path();
810 if let Some(args) = sess.target.target.options.pre_link_args.get(&flavor) {
813 if let Some(ref args) = sess.opts.debugging_opts.pre_link_args {
816 cmd.args(&sess.opts.debugging_opts.pre_link_arg);
818 let pre_link_objects = if crate_type == config::CrateTypeExecutable {
819 &sess.target.target.options.pre_link_objects_exe
821 &sess.target.target.options.pre_link_objects_dll
823 for obj in pre_link_objects {
824 cmd.arg(root.join(obj));
827 if sess.target.target.options.is_like_emscripten {
829 cmd.arg(if sess.panic_strategy() == PanicStrategy::Abort {
830 "DISABLE_EXCEPTION_CATCHING=1"
832 "DISABLE_EXCEPTION_CATCHING=0"
837 let mut linker = trans.linker_info.to_linker(cmd, &sess);
838 link_args(&mut *linker, sess, crate_type, tmpdir,
839 objects, out_filename, outputs, trans);
840 cmd = linker.finalize();
842 if let Some(args) = sess.target.target.options.late_link_args.get(&flavor) {
845 for obj in &sess.target.target.options.post_link_objects {
846 cmd.arg(root.join(obj));
848 if let Some(args) = sess.target.target.options.post_link_args.get(&flavor) {
851 for &(ref k, ref v) in &sess.target.target.options.link_env {
855 if sess.opts.debugging_opts.print_link_args {
856 println!("{:?}", &cmd);
859 // May have not found libraries in the right formats.
860 sess.abort_if_errors();
862 // Invoke the system linker
864 // Note that there's a terribly awful hack that really shouldn't be present
865 // in any compiler. Here an environment variable is supported to
866 // automatically retry the linker invocation if the linker looks like it
869 // Gee that seems odd, normally segfaults are things we want to know about!
870 // Unfortunately though in rust-lang/rust#38878 we're experiencing the
871 // linker segfaulting on Travis quite a bit which is causing quite a bit of
872 // pain to land PRs when they spuriously fail due to a segfault.
874 // The issue #38878 has some more debugging information on it as well, but
875 // this unfortunately looks like it's just a race condition in macOS's linker
876 // with some thread pool working in the background. It seems that no one
877 // currently knows a fix for this so in the meantime we're left with this...
879 let retry_on_segfault = env::var("RUSTC_RETRY_LINKER_ON_SEGFAULT").is_ok();
884 prog = time(sess.time_passes(), "running linker", || cmd.output());
885 if !retry_on_segfault || i > 3 {
888 let output = match prog {
889 Ok(ref output) => output,
892 if output.status.success() {
895 let mut out = output.stderr.clone();
896 out.extend(&output.stdout);
897 let out = String::from_utf8_lossy(&out);
898 let msg = "clang: error: unable to execute command: \
899 Segmentation fault: 11";
900 if !out.contains(msg) {
904 sess.struct_warn("looks like the linker segfaulted when we tried to \
905 call it, automatically retrying again")
906 .note(&format!("{:?}", cmd))
913 fn escape_string(s: &[u8]) -> String {
914 str::from_utf8(s).map(|s| s.to_owned())
915 .unwrap_or_else(|_| {
916 let mut x = "Non-UTF-8 output: ".to_string();
918 .flat_map(|&b| ascii::escape_default(b))
919 .map(|b| char::from_u32(b as u32).unwrap()));
923 if !prog.status.success() {
924 let mut output = prog.stderr.clone();
925 output.extend_from_slice(&prog.stdout);
926 sess.struct_err(&format!("linking with `{}` failed: {}",
929 .note(&format!("{:?}", &cmd))
930 .note(&escape_string(&output))
932 sess.abort_if_errors();
934 info!("linker stderr:\n{}", escape_string(&prog.stderr));
935 info!("linker stdout:\n{}", escape_string(&prog.stdout));
938 sess.struct_err(&format!("could not exec the linker `{}`: {}", pname, e))
939 .note(&format!("{:?}", &cmd))
941 if sess.target.target.options.is_like_msvc && e.kind() == io::ErrorKind::NotFound {
942 sess.note_without_error("the msvc targets depend on the msvc linker \
943 but `link.exe` was not found");
944 sess.note_without_error("please ensure that VS 2013 or VS 2015 was installed \
945 with the Visual C++ option");
947 sess.abort_if_errors();
952 // On macOS, debuggers need this utility to get run to do some munging of
954 if sess.target.target.options.is_like_osx && sess.opts.debuginfo != NoDebugInfo {
955 match Command::new("dsymutil").arg(out_filename).output() {
957 Err(e) => sess.fatal(&format!("failed to run dsymutil: {}", e)),
962 fn link_args(cmd: &mut Linker,
964 crate_type: config::CrateType,
968 outputs: &OutputFilenames,
969 trans: &CrateTranslation) {
971 // The default library location, we need this to find the runtime.
972 // The location of crates will be determined as needed.
973 let lib_path = sess.target_filesearch(PathKind::All).get_lib_path();
976 let t = &sess.target.target;
978 cmd.include_path(&fix_windows_verbatim_for_gcc(&lib_path));
982 cmd.output_filename(out_filename);
984 if crate_type == config::CrateTypeExecutable &&
985 sess.target.target.options.is_like_windows {
986 if let Some(ref s) = trans.windows_subsystem {
991 // If we're building a dynamic library then some platforms need to make sure
992 // that all symbols are exported correctly from the dynamic library.
993 if crate_type != config::CrateTypeExecutable ||
994 sess.target.target.options.is_like_emscripten {
995 cmd.export_symbols(tmpdir, crate_type);
998 // When linking a dynamic library, we put the metadata into a section of the
999 // executable. This metadata is in a separate object file from the main
1000 // object file, so we link that in here.
1001 if crate_type == config::CrateTypeDylib ||
1002 crate_type == config::CrateTypeProcMacro {
1003 cmd.add_object(&outputs.with_extension(METADATA_OBJ_NAME));
1006 if trans.allocator_module.is_some() {
1007 cmd.add_object(&outputs.with_extension(ALLOCATOR_OBJ_NAME));
1010 // Try to strip as much out of the generated object by removing unused
1011 // sections if possible. See more comments in linker.rs
1012 if !sess.opts.cg.link_dead_code {
1013 let keep_metadata = crate_type == config::CrateTypeDylib;
1014 cmd.gc_sections(keep_metadata);
1017 let used_link_args = sess.cstore.used_link_args();
1019 if crate_type == config::CrateTypeExecutable &&
1020 t.options.position_independent_executables {
1021 let empty_vec = Vec::new();
1022 let args = sess.opts.cg.link_args.as_ref().unwrap_or(&empty_vec);
1023 let more_args = &sess.opts.cg.link_arg;
1024 let mut args = args.iter().chain(more_args.iter()).chain(used_link_args.iter());
1026 if get_reloc_model(sess) == llvm::RelocMode::PIC
1027 && !args.any(|x| *x == "-static") {
1028 cmd.position_independent_executable();
1032 // Pass optimization flags down to the linker.
1035 // Pass debuginfo flags down to the linker.
1038 // We want to prevent the compiler from accidentally leaking in any system
1039 // libraries, so we explicitly ask gcc to not link to any libraries by
1040 // default. Note that this does not happen for windows because windows pulls
1041 // in some large number of libraries and I couldn't quite figure out which
1042 // subset we wanted.
1043 if t.options.no_default_libraries {
1044 cmd.no_default_libraries();
1047 // Take careful note of the ordering of the arguments we pass to the linker
1048 // here. Linkers will assume that things on the left depend on things to the
1049 // right. Things on the right cannot depend on things on the left. This is
1050 // all formally implemented in terms of resolving symbols (libs on the right
1051 // resolve unknown symbols of libs on the left, but not vice versa).
1053 // For this reason, we have organized the arguments we pass to the linker as
1056 // 1. The local object that LLVM just generated
1057 // 2. Local native libraries
1058 // 3. Upstream rust libraries
1059 // 4. Upstream native libraries
1061 // The rationale behind this ordering is that those items lower down in the
1062 // list can't depend on items higher up in the list. For example nothing can
1063 // depend on what we just generated (e.g. that'd be a circular dependency).
1064 // Upstream rust libraries are not allowed to depend on our local native
1065 // libraries as that would violate the structure of the DAG, in that
1066 // scenario they are required to link to them as well in a shared fashion.
1068 // Note that upstream rust libraries may contain native dependencies as
1069 // well, but they also can't depend on what we just started to add to the
1070 // link line. And finally upstream native libraries can't depend on anything
1071 // in this DAG so far because they're only dylibs and dylibs can only depend
1072 // on other dylibs (e.g. other native deps).
1073 add_local_native_libraries(cmd, sess);
1074 add_upstream_rust_crates(cmd, sess, crate_type, tmpdir);
1075 add_upstream_native_libraries(cmd, sess, crate_type);
1077 // # Telling the linker what we're doing
1079 if crate_type != config::CrateTypeExecutable {
1080 cmd.build_dylib(out_filename);
1083 // FIXME (#2397): At some point we want to rpath our guesses as to
1084 // where extern libraries might live, based on the
1085 // addl_lib_search_paths
1086 if sess.opts.cg.rpath {
1087 let sysroot = sess.sysroot();
1088 let target_triple = &sess.opts.target_triple;
1089 let mut get_install_prefix_lib_path = || {
1090 let install_prefix = option_env!("CFG_PREFIX").expect("CFG_PREFIX");
1091 let tlib = filesearch::relative_target_lib_path(sysroot, target_triple);
1092 let mut path = PathBuf::from(install_prefix);
1097 let mut rpath_config = RPathConfig {
1098 used_crates: sess.cstore.used_crates(LinkagePreference::RequireDynamic),
1099 out_filename: out_filename.to_path_buf(),
1100 has_rpath: sess.target.target.options.has_rpath,
1101 is_like_osx: sess.target.target.options.is_like_osx,
1102 linker_is_gnu: sess.target.target.options.linker_is_gnu,
1103 get_install_prefix_lib_path: &mut get_install_prefix_lib_path,
1105 cmd.args(&rpath::get_rpath_flags(&mut rpath_config));
1108 // Finally add all the linker arguments provided on the command line along
1109 // with any #[link_args] attributes found inside the crate
1110 if let Some(ref args) = sess.opts.cg.link_args {
1113 cmd.args(&sess.opts.cg.link_arg);
1114 cmd.args(&used_link_args);
1117 // # Native library linking
1119 // User-supplied library search paths (-L on the command line). These are
1120 // the same paths used to find Rust crates, so some of them may have been
1121 // added already by the previous crate linking code. This only allows them
1122 // to be found at compile time so it is still entirely up to outside
1123 // forces to make sure that library can be found at runtime.
1125 // Also note that the native libraries linked here are only the ones located
1126 // in the current crate. Upstream crates with native library dependencies
1127 // may have their native library pulled in above.
1128 fn add_local_native_libraries(cmd: &mut Linker, sess: &Session) {
1129 sess.target_filesearch(PathKind::All).for_each_lib_search_path(|path, k| {
1131 PathKind::Framework => { cmd.framework_path(path); }
1132 _ => { cmd.include_path(&fix_windows_verbatim_for_gcc(path)); }
1136 let relevant_libs = sess.cstore.used_libraries().into_iter().filter(|l| {
1137 relevant_lib(sess, l)
1140 let search_path = archive_search_paths(sess);
1141 for lib in relevant_libs {
1143 NativeLibraryKind::NativeUnknown => cmd.link_dylib(&lib.name.as_str()),
1144 NativeLibraryKind::NativeFramework => cmd.link_framework(&lib.name.as_str()),
1145 NativeLibraryKind::NativeStaticNobundle => cmd.link_staticlib(&lib.name.as_str()),
1146 NativeLibraryKind::NativeStatic => cmd.link_whole_staticlib(&lib.name.as_str(),
1152 // # Rust Crate linking
1154 // Rust crates are not considered at all when creating an rlib output. All
1155 // dependencies will be linked when producing the final output (instead of
1156 // the intermediate rlib version)
1157 fn add_upstream_rust_crates(cmd: &mut Linker,
1159 crate_type: config::CrateType,
1161 // All of the heavy lifting has previously been accomplished by the
1162 // dependency_format module of the compiler. This is just crawling the
1163 // output of that module, adding crates as necessary.
1165 // Linking to a rlib involves just passing it to the linker (the linker
1166 // will slurp up the object files inside), and linking to a dynamic library
1167 // involves just passing the right -l flag.
1169 let formats = sess.dependency_formats.borrow();
1170 let data = formats.get(&crate_type).unwrap();
1172 // Invoke get_used_crates to ensure that we get a topological sorting of
1174 let deps = sess.cstore.used_crates(LinkagePreference::RequireDynamic);
1176 let mut compiler_builtins = None;
1178 for &(cnum, _) in &deps {
1179 // We may not pass all crates through to the linker. Some crates may
1180 // appear statically in an existing dylib, meaning we'll pick up all the
1181 // symbols from the dylib.
1182 let src = sess.cstore.used_crate_source(cnum);
1183 match data[cnum.as_usize() - 1] {
1184 _ if sess.cstore.is_profiler_runtime(cnum) => {
1185 add_static_crate(cmd, sess, tmpdir, crate_type, cnum);
1187 _ if sess.cstore.is_sanitizer_runtime(cnum) => {
1188 link_sanitizer_runtime(cmd, sess, tmpdir, cnum);
1190 // compiler-builtins are always placed last to ensure that they're
1191 // linked correctly.
1192 _ if sess.cstore.is_compiler_builtins(cnum) => {
1193 assert!(compiler_builtins.is_none());
1194 compiler_builtins = Some(cnum);
1196 Linkage::NotLinked |
1197 Linkage::IncludedFromDylib => {}
1198 Linkage::Static => {
1199 add_static_crate(cmd, sess, tmpdir, crate_type, cnum);
1201 Linkage::Dynamic => {
1202 add_dynamic_crate(cmd, sess, &src.dylib.unwrap().0)
1207 // compiler-builtins are always placed last to ensure that they're
1208 // linked correctly.
1209 // We must always link the `compiler_builtins` crate statically. Even if it
1210 // was already "included" in a dylib (e.g. `libstd` when `-C prefer-dynamic`
1212 if let Some(cnum) = compiler_builtins {
1213 add_static_crate(cmd, sess, tmpdir, crate_type, cnum);
1216 // Converts a library file-stem into a cc -l argument
1217 fn unlib<'a>(config: &config::Config, stem: &'a str) -> &'a str {
1218 if stem.starts_with("lib") && !config.target.options.is_like_windows {
1225 // We must link the sanitizer runtime using -Wl,--whole-archive but since
1226 // it's packed in a .rlib, it contains stuff that are not objects that will
1227 // make the linker error. So we must remove those bits from the .rlib before
1229 fn link_sanitizer_runtime(cmd: &mut Linker,
1233 let src = sess.cstore.used_crate_source(cnum);
1234 let cratepath = &src.rlib.unwrap().0;
1236 if sess.target.target.options.is_like_osx {
1237 // On Apple platforms, the sanitizer is always built as a dylib, and
1238 // LLVM will link to `@rpath/*.dylib`, so we need to specify an
1239 // rpath to the library as well (the rpath should be absolute, see
1240 // PR #41352 for details).
1242 // FIXME: Remove this logic into librustc_*san once Cargo supports it
1243 let rpath = cratepath.parent().unwrap();
1244 let rpath = rpath.to_str().expect("non-utf8 component in path");
1245 cmd.args(&["-Wl,-rpath".into(), "-Xlinker".into(), rpath.into()]);
1248 let dst = tmpdir.join(cratepath.file_name().unwrap());
1249 let cfg = archive_config(sess, &dst, Some(cratepath));
1250 let mut archive = ArchiveBuilder::new(cfg);
1251 archive.update_symbols();
1253 for f in archive.src_files() {
1254 if f.ends_with("bytecode.deflate") || f == METADATA_FILENAME {
1255 archive.remove_file(&f);
1262 cmd.link_whole_rlib(&dst);
1265 // Adds the static "rlib" versions of all crates to the command line.
1266 // There's a bit of magic which happens here specifically related to LTO and
1267 // dynamic libraries. Specifically:
1269 // * For LTO, we remove upstream object files.
1270 // * For dylibs we remove metadata and bytecode from upstream rlibs
1272 // When performing LTO, almost(*) all of the bytecode from the upstream
1273 // libraries has already been included in our object file output. As a
1274 // result we need to remove the object files in the upstream libraries so
1275 // the linker doesn't try to include them twice (or whine about duplicate
1276 // symbols). We must continue to include the rest of the rlib, however, as
1277 // it may contain static native libraries which must be linked in.
1279 // (*) Crates marked with `#![no_builtins]` don't participate in LTO and
1280 // their bytecode wasn't included. The object files in those libraries must
1281 // still be passed to the linker.
1283 // When making a dynamic library, linkers by default don't include any
1284 // object files in an archive if they're not necessary to resolve the link.
1285 // We basically want to convert the archive (rlib) to a dylib, though, so we
1286 // *do* want everything included in the output, regardless of whether the
1287 // linker thinks it's needed or not. As a result we must use the
1288 // --whole-archive option (or the platform equivalent). When using this
1289 // option the linker will fail if there are non-objects in the archive (such
1290 // as our own metadata and/or bytecode). All in all, for rlibs to be
1291 // entirely included in dylibs, we need to remove all non-object files.
1293 // Note, however, that if we're not doing LTO or we're not producing a dylib
1294 // (aka we're making an executable), we can just pass the rlib blindly to
1295 // the linker (fast) because it's fine if it's not actually included as
1296 // we're at the end of the dependency chain.
1297 fn add_static_crate(cmd: &mut Linker,
1300 crate_type: config::CrateType,
1302 let src = sess.cstore.used_crate_source(cnum);
1303 let cratepath = &src.rlib.unwrap().0;
1305 // See the comment above in `link_staticlib` and `link_rlib` for why if
1306 // there's a static library that's not relevant we skip all object
1308 let native_libs = sess.cstore.native_libraries(cnum);
1309 let skip_native = native_libs.iter().any(|lib| {
1310 lib.kind == NativeLibraryKind::NativeStatic && !relevant_lib(sess, lib)
1313 if (!sess.lto() || ignored_for_lto(sess, cnum)) &&
1314 crate_type != config::CrateTypeDylib &&
1316 cmd.link_rlib(&fix_windows_verbatim_for_gcc(cratepath));
1320 let dst = tmpdir.join(cratepath.file_name().unwrap());
1321 let name = cratepath.file_name().unwrap().to_str().unwrap();
1322 let name = &name[3..name.len() - 5]; // chop off lib/.rlib
1324 time(sess.time_passes(), &format!("altering {}.rlib", name), || {
1325 let cfg = archive_config(sess, &dst, Some(cratepath));
1326 let mut archive = ArchiveBuilder::new(cfg);
1327 archive.update_symbols();
1329 let mut any_objects = false;
1330 for f in archive.src_files() {
1331 if f.ends_with("bytecode.deflate") || f == METADATA_FILENAME {
1332 archive.remove_file(&f);
1336 let canonical = f.replace("-", "_");
1337 let canonical_name = name.replace("-", "_");
1339 let is_rust_object =
1340 canonical.starts_with(&canonical_name) && {
1341 let num = &f[name.len()..f.len() - 2];
1342 num.len() > 0 && num[1..].parse::<u32>().is_ok()
1345 // If we've been requested to skip all native object files
1346 // (those not generated by the rust compiler) then we can skip
1347 // this file. See above for why we may want to do this.
1348 let skip_because_cfg_say_so = skip_native && !is_rust_object;
1350 // If we're performing LTO and this is a rust-generated object
1351 // file, then we don't need the object file as it's part of the
1352 // LTO module. Note that `#![no_builtins]` is excluded from LTO,
1353 // though, so we let that object file slide.
1354 let skip_because_lto = sess.lto() && is_rust_object &&
1355 !sess.cstore.is_no_builtins(cnum);
1357 if skip_because_cfg_say_so || skip_because_lto {
1358 archive.remove_file(&f);
1369 // If we're creating a dylib, then we need to include the
1370 // whole of each object in our archive into that artifact. This is
1371 // because a `dylib` can be reused as an intermediate artifact.
1373 // Note, though, that we don't want to include the whole of a
1374 // compiler-builtins crate (e.g. compiler-rt) because it'll get
1375 // repeatedly linked anyway.
1376 if crate_type == config::CrateTypeDylib &&
1377 !sess.cstore.is_compiler_builtins(cnum) {
1378 cmd.link_whole_rlib(&fix_windows_verbatim_for_gcc(&dst));
1380 cmd.link_rlib(&fix_windows_verbatim_for_gcc(&dst));
1385 // Same thing as above, but for dynamic crates instead of static crates.
1386 fn add_dynamic_crate(cmd: &mut Linker, sess: &Session, cratepath: &Path) {
1387 // If we're performing LTO, then it should have been previously required
1388 // that all upstream rust dependencies were available in an rlib format.
1389 assert!(!sess.lto());
1391 // Just need to tell the linker about where the library lives and
1393 let parent = cratepath.parent();
1394 if let Some(dir) = parent {
1395 cmd.include_path(&fix_windows_verbatim_for_gcc(dir));
1397 let filestem = cratepath.file_stem().unwrap().to_str().unwrap();
1398 cmd.link_rust_dylib(&unlib(&sess.target, filestem),
1399 parent.unwrap_or(Path::new("")));
1403 // Link in all of our upstream crates' native dependencies. Remember that
1404 // all of these upstream native dependencies are all non-static
1405 // dependencies. We've got two cases then:
1407 // 1. The upstream crate is an rlib. In this case we *must* link in the
1408 // native dependency because the rlib is just an archive.
1410 // 2. The upstream crate is a dylib. In order to use the dylib, we have to
1411 // have the dependency present on the system somewhere. Thus, we don't
1412 // gain a whole lot from not linking in the dynamic dependency to this
1415 // The use case for this is a little subtle. In theory the native
1416 // dependencies of a crate are purely an implementation detail of the crate
1417 // itself, but the problem arises with generic and inlined functions. If a
1418 // generic function calls a native function, then the generic function must
1419 // be instantiated in the target crate, meaning that the native symbol must
1420 // also be resolved in the target crate.
1421 fn add_upstream_native_libraries(cmd: &mut Linker, sess: &Session, crate_type: config::CrateType) {
1422 // Be sure to use a topological sorting of crates because there may be
1423 // interdependencies between native libraries. When passing -nodefaultlibs,
1424 // for example, almost all native libraries depend on libc, so we have to
1425 // make sure that's all the way at the right (liblibc is near the base of
1426 // the dependency chain).
1428 // This passes RequireStatic, but the actual requirement doesn't matter,
1429 // we're just getting an ordering of crate numbers, we're not worried about
1431 let formats = sess.dependency_formats.borrow();
1432 let data = formats.get(&crate_type).unwrap();
1434 let crates = sess.cstore.used_crates(LinkagePreference::RequireStatic);
1435 for (cnum, _) in crates {
1436 for lib in sess.cstore.native_libraries(cnum) {
1437 if !relevant_lib(sess, &lib) {
1441 NativeLibraryKind::NativeUnknown => cmd.link_dylib(&lib.name.as_str()),
1442 NativeLibraryKind::NativeFramework => cmd.link_framework(&lib.name.as_str()),
1443 NativeLibraryKind::NativeStaticNobundle => {
1444 // Link "static-nobundle" native libs only if the crate they originate from
1445 // is being linked statically to the current crate. If it's linked dynamically
1446 // or is an rlib already included via some other dylib crate, the symbols from
1447 // native libs will have already been included in that dylib.
1448 if data[cnum.as_usize() - 1] == Linkage::Static {
1449 cmd.link_staticlib(&lib.name.as_str())
1452 // ignore statically included native libraries here as we've
1453 // already included them when we included the rust library
1455 NativeLibraryKind::NativeStatic => {}
1461 fn relevant_lib(sess: &Session, lib: &NativeLibrary) -> bool {
1463 Some(ref cfg) => attr::cfg_matches(cfg, &sess.parse_sess, None),