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::bytecode
::RLIB_BYTECODE_EXTENSION
;
13 use super::linker
::Linker
;
14 use super::command
::Command
;
15 use super::rpath
::RPathConfig
;
17 use metadata
::METADATA_FILENAME
;
18 use rustc
::session
::config
::{self, NoDebugInfo, OutputFilenames, OutputType, PrintRequest}
;
19 use rustc
::session
::config
::{RUST_CGU_EXT, Lto}
;
20 use rustc
::session
::filesearch
;
21 use rustc
::session
::search_paths
::PathKind
;
22 use rustc
::session
::Session
;
23 use rustc
::middle
::cstore
::{NativeLibrary, LibSource, NativeLibraryKind}
;
24 use rustc
::middle
::dependency_format
::Linkage
;
25 use {CrateTranslation, CrateInfo}
;
26 use rustc
::util
::common
::time
;
27 use rustc
::util
::fs
::fix_windows_verbatim_for_gcc
;
28 use rustc
::hir
::def_id
::CrateNum
;
30 use rustc_back
::{PanicStrategy, RelroLevel, LinkerFlavor}
;
31 use context
::get_reloc_model
;
37 use std
::ffi
::OsString
;
41 use std
::path
::{Path, PathBuf}
;
42 use std
::process
::{Output, Stdio}
;
46 /// The LLVM module name containing crate-metadata. This includes a `.` on
47 /// purpose, so it cannot clash with the name of a user-defined module.
48 pub const METADATA_MODULE_NAME
: &'
static str = "crate.metadata";
50 // same as for metadata above, but for allocator shim
51 pub const ALLOCATOR_MODULE_NAME
: &'
static str = "crate.allocator";
53 pub use rustc_trans_utils
::link
::{find_crate_name
, filename_for_input
, default_output_for_target
,
54 invalid_output_for_target
, build_link_meta
, out_filename
,
55 check_file_is_writeable
};
57 // The third parameter is for env vars, used on windows to set up the
58 // path for MSVC to find its DLLs, and gcc to find its bundled
60 pub fn get_linker(sess
: &Session
) -> (PathBuf
, Command
, Vec
<(OsString
, OsString
)>) {
61 let envs
= vec
![("PATH".into(), command_path(sess
))];
63 // If our linker looks like a batch script on Windows then to execute this
64 // we'll need to spawn `cmd` explicitly. This is primarily done to handle
65 // emscripten where the linker is `emcc.bat` and needs to be spawned as
66 // `cmd /c emcc.bat ...`.
68 // This worked historically but is needed manually since #42436 (regression
69 // was tagged as #42791) and some more info can be found on #44443 for
71 let cmd
= |linker
: &Path
| {
72 if let Some(linker
) = linker
.to_str() {
73 if cfg
!(windows
) && linker
.ends_with(".bat") {
74 return Command
::bat_script(linker
)
80 if let Some(ref linker
) = sess
.opts
.cg
.linker
{
81 (linker
.clone(), cmd(linker
), envs
)
82 } else if sess
.target
.target
.options
.is_like_msvc
{
83 let (cmd
, envs
) = msvc_link_exe_cmd(sess
);
84 (PathBuf
::from("link.exe"), cmd
, envs
)
86 let linker
= PathBuf
::from(&sess
.target
.target
.options
.linker
);
87 let cmd
= cmd(&linker
);
93 pub fn msvc_link_exe_cmd(sess
: &Session
) -> (Command
, Vec
<(OsString
, OsString
)>) {
94 use cc
::windows_registry
;
96 let target
= &sess
.opts
.target_triple
;
97 let tool
= windows_registry
::find_tool(target
, "link.exe");
99 if let Some(tool
) = tool
{
100 let mut cmd
= Command
::new(tool
.path());
101 cmd
.args(tool
.args());
102 for &(ref k
, ref v
) in tool
.env() {
105 let envs
= tool
.env().to_vec();
108 debug
!("Failed to locate linker.");
109 (Command
::new("link.exe"), vec
![])
114 pub fn msvc_link_exe_cmd(_sess
: &Session
) -> (Command
, Vec
<(OsString
, OsString
)>) {
115 (Command
::new("link.exe"), vec
![])
118 fn command_path(sess
: &Session
) -> OsString
{
119 // The compiler's sysroot often has some bundled tools, so add it to the
120 // PATH for the child.
121 let mut new_path
= sess
.host_filesearch(PathKind
::All
)
122 .get_tools_search_paths();
123 if let Some(path
) = env
::var_os("PATH") {
124 new_path
.extend(env
::split_paths(&path
));
126 env
::join_paths(new_path
).unwrap()
129 pub fn remove(sess
: &Session
, path
: &Path
) {
130 match fs
::remove_file(path
) {
133 sess
.err(&format
!("failed to remove {}: {}",
140 /// Perform the linkage portion of the compilation phase. This will generate all
141 /// of the requested outputs for this compilation session.
142 pub(crate) fn link_binary(sess
: &Session
,
143 trans
: &CrateTranslation
,
144 outputs
: &OutputFilenames
,
145 crate_name
: &str) -> Vec
<PathBuf
> {
146 let mut out_filenames
= Vec
::new();
147 for &crate_type
in sess
.crate_types
.borrow().iter() {
148 // Ignore executable crates if we have -Z no-trans, as they will error.
149 if (sess
.opts
.debugging_opts
.no_trans
||
150 !sess
.opts
.output_types
.should_trans()) &&
151 crate_type
== config
::CrateTypeExecutable
{
155 if invalid_output_for_target(sess
, crate_type
) {
156 bug
!("invalid output type `{:?}` for target os `{}`",
157 crate_type
, sess
.opts
.target_triple
);
159 let mut out_files
= link_binary_output(sess
,
164 out_filenames
.append(&mut out_files
);
167 // Remove the temporary object file and metadata if we aren't saving temps
168 if !sess
.opts
.cg
.save_temps
{
169 if sess
.opts
.output_types
.should_trans() {
170 for obj
in trans
.modules
.iter().filter_map(|m
| m
.object
.as_ref()) {
174 for obj
in trans
.modules
.iter().filter_map(|m
| m
.bytecode_compressed
.as_ref()) {
177 if let Some(ref obj
) = trans
.metadata_module
.object
{
180 if let Some(ref allocator
) = trans
.allocator_module
{
181 if let Some(ref obj
) = allocator
.object
{
184 if let Some(ref bc
) = allocator
.bytecode_compressed
{
193 fn filename_for_metadata(sess
: &Session
, crate_name
: &str, outputs
: &OutputFilenames
) -> PathBuf
{
194 let out_filename
= outputs
.single_output_file
.clone()
197 .join(&format
!("lib{}{}.rmeta", crate_name
, sess
.opts
.cg
.extra_filename
)));
198 check_file_is_writeable(&out_filename
, sess
);
202 pub(crate) fn each_linked_rlib(sess
: &Session
,
204 f
: &mut FnMut(CrateNum
, &Path
)) -> Result
<(), String
> {
205 let crates
= info
.used_crates_static
.iter();
206 let fmts
= sess
.dependency_formats
.borrow();
207 let fmts
= fmts
.get(&config
::CrateTypeExecutable
)
208 .or_else(|| fmts
.get(&config
::CrateTypeStaticlib
))
209 .or_else(|| fmts
.get(&config
::CrateTypeCdylib
))
210 .or_else(|| fmts
.get(&config
::CrateTypeProcMacro
));
211 let fmts
= match fmts
{
213 None
=> return Err(format
!("could not find formats for rlibs"))
215 for &(cnum
, ref path
) in crates
{
216 match fmts
.get(cnum
.as_usize() - 1) {
217 Some(&Linkage
::NotLinked
) |
218 Some(&Linkage
::IncludedFromDylib
) => continue,
220 None
=> return Err(format
!("could not find formats for rlibs"))
222 let name
= &info
.crate_name
[&cnum
];
223 let path
= match *path
{
224 LibSource
::Some(ref p
) => p
,
225 LibSource
::MetadataOnly
=> {
226 return Err(format
!("could not find rlib for: `{}`, found rmeta (metadata) file",
230 return Err(format
!("could not find rlib for: `{}`", name
))
238 /// Returns a boolean indicating whether the specified crate should be ignored
241 /// Crates ignored during LTO are not lumped together in the "massive object
242 /// file" that we create and are linked in their normal rlib states. See
243 /// comments below for what crates do not participate in LTO.
245 /// It's unusual for a crate to not participate in LTO. Typically only
246 /// compiler-specific and unstable crates have a reason to not participate in
248 pub(crate) fn ignored_for_lto(sess
: &Session
, info
: &CrateInfo
, cnum
: CrateNum
) -> bool
{
249 // If our target enables builtin function lowering in LLVM then the
250 // crates providing these functions don't participate in LTO (e.g.
251 // no_builtins or compiler builtins crates).
252 !sess
.target
.target
.options
.no_builtins
&&
253 (info
.is_no_builtins
.contains(&cnum
) || info
.compiler_builtins
== Some(cnum
))
256 fn link_binary_output(sess
: &Session
,
257 trans
: &CrateTranslation
,
258 crate_type
: config
::CrateType
,
259 outputs
: &OutputFilenames
,
260 crate_name
: &str) -> Vec
<PathBuf
> {
261 for obj
in trans
.modules
.iter().filter_map(|m
| m
.object
.as_ref()) {
262 check_file_is_writeable(obj
, sess
);
265 let mut out_filenames
= vec
![];
267 if outputs
.outputs
.contains_key(&OutputType
::Metadata
) {
268 let out_filename
= filename_for_metadata(sess
, crate_name
, outputs
);
269 // To avoid races with another rustc process scanning the output directory,
270 // we need to write the file somewhere else and atomically move it to its
271 // final destination, with a `fs::rename` call. In order for the rename to
272 // always succeed, the temporary file needs to be on the same filesystem,
273 // which is why we create it inside the output directory specifically.
274 let metadata_tmpdir
= match TempDir
::new_in(out_filename
.parent().unwrap(), "rmeta") {
275 Ok(tmpdir
) => tmpdir
,
276 Err(err
) => sess
.fatal(&format
!("couldn't create a temp dir: {}", err
)),
278 let metadata
= emit_metadata(sess
, trans
, &metadata_tmpdir
);
279 if let Err(e
) = fs
::rename(metadata
, &out_filename
) {
280 sess
.fatal(&format
!("failed to write {}: {}", out_filename
.display(), e
));
282 out_filenames
.push(out_filename
);
285 let tmpdir
= match TempDir
::new("rustc") {
286 Ok(tmpdir
) => tmpdir
,
287 Err(err
) => sess
.fatal(&format
!("couldn't create a temp dir: {}", err
)),
290 if outputs
.outputs
.should_trans() {
291 let out_filename
= out_filename(sess
, crate_type
, outputs
, crate_name
);
293 config
::CrateTypeRlib
=> {
300 config
::CrateTypeStaticlib
=> {
301 link_staticlib(sess
, trans
, &out_filename
, &tmpdir
);
304 link_natively(sess
, crate_type
, &out_filename
, trans
, tmpdir
.path());
307 out_filenames
.push(out_filename
);
310 if sess
.opts
.cg
.save_temps
{
311 let _
= tmpdir
.into_path();
317 fn archive_search_paths(sess
: &Session
) -> Vec
<PathBuf
> {
318 let mut search
= Vec
::new();
319 sess
.target_filesearch(PathKind
::Native
).for_each_lib_search_path(|path
, _
| {
320 search
.push(path
.to_path_buf());
325 fn archive_config
<'a
>(sess
: &'a Session
,
327 input
: Option
<&Path
>) -> ArchiveConfig
<'a
> {
330 dst
: output
.to_path_buf(),
331 src
: input
.map(|p
| p
.to_path_buf()),
332 lib_search_paths
: archive_search_paths(sess
),
336 /// We use a temp directory here to avoid races between concurrent rustc processes,
337 /// such as builds in the same directory using the same filename for metadata while
338 /// building an `.rlib` (stomping over one another), or writing an `.rmeta` into a
339 /// directory being searched for `extern crate` (observing an incomplete file).
340 /// The returned path is the temporary file containing the complete metadata.
341 fn emit_metadata
<'a
>(sess
: &'a Session
, trans
: &CrateTranslation
, tmpdir
: &TempDir
)
343 let out_filename
= tmpdir
.path().join(METADATA_FILENAME
);
344 let result
= fs
::write(&out_filename
, &trans
.metadata
.raw_data
);
346 if let Err(e
) = result
{
347 sess
.fatal(&format
!("failed to write {}: {}", out_filename
.display(), e
));
360 // An rlib in its current incarnation is essentially a renamed .a file. The
361 // rlib primarily contains the object file of the crate, but it also contains
362 // all of the object files from native libraries. This is done by unzipping
363 // native libraries and inserting all of the contents into this archive.
364 fn link_rlib
<'a
>(sess
: &'a Session
,
365 trans
: &CrateTranslation
,
368 tmpdir
: &TempDir
) -> ArchiveBuilder
<'a
> {
369 info
!("preparing rlib to {:?}", out_filename
);
370 let mut ab
= ArchiveBuilder
::new(archive_config(sess
, out_filename
, None
));
372 for obj
in trans
.modules
.iter().filter_map(|m
| m
.object
.as_ref()) {
376 // Note that in this loop we are ignoring the value of `lib.cfg`. That is,
377 // we may not be configured to actually include a static library if we're
378 // adding it here. That's because later when we consume this rlib we'll
379 // decide whether we actually needed the static library or not.
381 // To do this "correctly" we'd need to keep track of which libraries added
382 // which object files to the archive. We don't do that here, however. The
383 // #[link(cfg(..))] feature is unstable, though, and only intended to get
384 // liblibc working. In that sense the check below just indicates that if
385 // there are any libraries we want to omit object files for at link time we
386 // just exclude all custom object files.
388 // Eventually if we want to stabilize or flesh out the #[link(cfg(..))]
389 // feature then we'll need to figure out how to record what objects were
390 // loaded from the libraries found here and then encode that into the
391 // metadata of the rlib we're generating somehow.
392 for lib
in trans
.crate_info
.used_libraries
.iter() {
394 NativeLibraryKind
::NativeStatic
=> {}
395 NativeLibraryKind
::NativeStaticNobundle
|
396 NativeLibraryKind
::NativeFramework
|
397 NativeLibraryKind
::NativeUnknown
=> continue,
399 ab
.add_native_library(&lib
.name
.as_str());
402 // After adding all files to the archive, we need to update the
403 // symbol table of the archive.
406 // Note that it is important that we add all of our non-object "magical
407 // files" *after* all of the object files in the archive. The reason for
408 // this is as follows:
410 // * When performing LTO, this archive will be modified to remove
411 // objects from above. The reason for this is described below.
413 // * When the system linker looks at an archive, it will attempt to
414 // determine the architecture of the archive in order to see whether its
417 // The algorithm for this detection is: iterate over the files in the
418 // archive. Skip magical SYMDEF names. Interpret the first file as an
419 // object file. Read architecture from the object file.
421 // * As one can probably see, if "metadata" and "foo.bc" were placed
422 // before all of the objects, then the architecture of this archive would
423 // not be correctly inferred once 'foo.o' is removed.
425 // Basically, all this means is that this code should not move above the
428 RlibFlavor
::Normal
=> {
429 // Instead of putting the metadata in an object file section, rlibs
430 // contain the metadata in a separate file.
431 ab
.add_file(&emit_metadata(sess
, trans
, tmpdir
));
433 // For LTO purposes, the bytecode of this library is also inserted
435 for bytecode
in trans
.modules
.iter().filter_map(|m
| m
.bytecode_compressed
.as_ref()) {
436 ab
.add_file(bytecode
);
439 // After adding all files to the archive, we need to update the
440 // symbol table of the archive. This currently dies on macOS (see
441 // #11162), and isn't necessary there anyway
442 if !sess
.target
.target
.options
.is_like_osx
{
447 RlibFlavor
::StaticlibBase
=> {
448 let obj
= trans
.allocator_module
450 .and_then(|m
| m
.object
.as_ref());
451 if let Some(obj
) = obj
{
460 // Create a static archive
462 // This is essentially the same thing as an rlib, but it also involves adding
463 // all of the upstream crates' objects into the archive. This will slurp in
464 // all of the native libraries of upstream dependencies as well.
466 // Additionally, there's no way for us to link dynamic libraries, so we warn
467 // about all dynamic library dependencies that they're not linked in.
469 // There's no need to include metadata in a static archive, so ensure to not
470 // link in the metadata object file (and also don't prepare the archive with a
472 fn link_staticlib(sess
: &Session
,
473 trans
: &CrateTranslation
,
476 let mut ab
= link_rlib(sess
,
478 RlibFlavor
::StaticlibBase
,
481 let mut all_native_libs
= vec
![];
483 let res
= each_linked_rlib(sess
, &trans
.crate_info
, &mut |cnum
, path
| {
484 let name
= &trans
.crate_info
.crate_name
[&cnum
];
485 let native_libs
= &trans
.crate_info
.native_libraries
[&cnum
];
487 // Here when we include the rlib into our staticlib we need to make a
488 // decision whether to include the extra object files along the way.
489 // These extra object files come from statically included native
490 // libraries, but they may be cfg'd away with #[link(cfg(..))].
492 // This unstable feature, though, only needs liblibc to work. The only
493 // use case there is where musl is statically included in liblibc.rlib,
494 // so if we don't want the included version we just need to skip it. As
495 // a result the logic here is that if *any* linked library is cfg'd away
496 // we just skip all object files.
498 // Clearly this is not sufficient for a general purpose feature, and
499 // we'd want to read from the library's metadata to determine which
500 // object files come from where and selectively skip them.
501 let skip_object_files
= native_libs
.iter().any(|lib
| {
502 lib
.kind
== NativeLibraryKind
::NativeStatic
&& !relevant_lib(sess
, lib
)
506 is_full_lto_enabled(sess
) &&
507 !ignored_for_lto(sess
, &trans
.crate_info
, cnum
),
508 skip_object_files
).unwrap();
510 all_native_libs
.extend(trans
.crate_info
.native_libraries
[&cnum
].iter().cloned());
512 if let Err(e
) = res
{
519 if !all_native_libs
.is_empty() {
520 if sess
.opts
.prints
.contains(&PrintRequest
::NativeStaticLibs
) {
521 print_native_static_libs(sess
, &all_native_libs
);
526 fn print_native_static_libs(sess
: &Session
, all_native_libs
: &[NativeLibrary
]) {
527 let lib_args
: Vec
<_
> = all_native_libs
.iter()
528 .filter(|l
| relevant_lib(sess
, l
))
529 .filter_map(|lib
| match lib
.kind
{
530 NativeLibraryKind
::NativeStaticNobundle
|
531 NativeLibraryKind
::NativeUnknown
=> {
532 if sess
.target
.target
.options
.is_like_msvc
{
533 Some(format
!("{}.lib", lib
.name
))
535 Some(format
!("-l{}", lib
.name
))
538 NativeLibraryKind
::NativeFramework
=> {
539 // ld-only syntax, since there are no frameworks in MSVC
540 Some(format
!("-framework {}", lib
.name
))
542 // These are included, no need to print them
543 NativeLibraryKind
::NativeStatic
=> None
,
546 if !lib_args
.is_empty() {
547 sess
.note_without_error("Link against the following native artifacts when linking \
548 against this static library. The order and any duplication \
549 can be significant on some platforms.");
550 // Prefix for greppability
551 sess
.note_without_error(&format
!("native-static-libs: {}", &lib_args
.join(" ")));
555 // Create a dynamic library or executable
557 // This will invoke the system linker/cc to create the resulting file. This
558 // links to all upstream files as well.
559 fn link_natively(sess
: &Session
,
560 crate_type
: config
::CrateType
,
562 trans
: &CrateTranslation
,
564 info
!("preparing {:?} to {:?}", crate_type
, out_filename
);
565 let flavor
= sess
.linker_flavor();
567 // The "binaryen linker" is massively special, so skip everything below.
568 if flavor
== LinkerFlavor
::Binaryen
{
569 return link_binaryen(sess
, crate_type
, out_filename
, trans
, tmpdir
);
572 // The invocations of cc share some flags across platforms
573 let (pname
, mut cmd
, envs
) = get_linker(sess
);
574 // This will set PATH on windows
577 let root
= sess
.target_filesearch(PathKind
::Native
).get_lib_path();
578 if let Some(args
) = sess
.target
.target
.options
.pre_link_args
.get(&flavor
) {
581 if let Some(ref args
) = sess
.opts
.debugging_opts
.pre_link_args
{
584 cmd
.args(&sess
.opts
.debugging_opts
.pre_link_arg
);
586 let pre_link_objects
= if crate_type
== config
::CrateTypeExecutable
{
587 &sess
.target
.target
.options
.pre_link_objects_exe
589 &sess
.target
.target
.options
.pre_link_objects_dll
591 for obj
in pre_link_objects
{
592 cmd
.arg(root
.join(obj
));
595 if sess
.target
.target
.options
.is_like_emscripten
{
597 cmd
.arg(if sess
.panic_strategy() == PanicStrategy
::Abort
{
598 "DISABLE_EXCEPTION_CATCHING=1"
600 "DISABLE_EXCEPTION_CATCHING=0"
605 let mut linker
= trans
.linker_info
.to_linker(cmd
, &sess
);
606 link_args(&mut *linker
, sess
, crate_type
, tmpdir
,
607 out_filename
, trans
);
608 cmd
= linker
.finalize();
610 if let Some(args
) = sess
.target
.target
.options
.late_link_args
.get(&flavor
) {
613 for obj
in &sess
.target
.target
.options
.post_link_objects
{
614 cmd
.arg(root
.join(obj
));
616 if let Some(args
) = sess
.target
.target
.options
.post_link_args
.get(&flavor
) {
619 for &(ref k
, ref v
) in &sess
.target
.target
.options
.link_env
{
623 if sess
.opts
.debugging_opts
.print_link_args
{
624 println
!("{:?}", &cmd
);
627 // May have not found libraries in the right formats.
628 sess
.abort_if_errors();
630 // Invoke the system linker
632 // Note that there's a terribly awful hack that really shouldn't be present
633 // in any compiler. Here an environment variable is supported to
634 // automatically retry the linker invocation if the linker looks like it
637 // Gee that seems odd, normally segfaults are things we want to know about!
638 // Unfortunately though in rust-lang/rust#38878 we're experiencing the
639 // linker segfaulting on Travis quite a bit which is causing quite a bit of
640 // pain to land PRs when they spuriously fail due to a segfault.
642 // The issue #38878 has some more debugging information on it as well, but
643 // this unfortunately looks like it's just a race condition in macOS's linker
644 // with some thread pool working in the background. It seems that no one
645 // currently knows a fix for this so in the meantime we're left with this...
647 let retry_on_segfault
= env
::var("RUSTC_RETRY_LINKER_ON_SEGFAULT").is_ok();
652 prog
= time(sess
.time_passes(), "running linker", || {
653 exec_linker(sess
, &mut cmd
, tmpdir
)
655 if !retry_on_segfault
|| i
> 3 {
658 let output
= match prog
{
659 Ok(ref output
) => output
,
662 if output
.status
.success() {
665 let mut out
= output
.stderr
.clone();
666 out
.extend(&output
.stdout
);
667 let out
= String
::from_utf8_lossy(&out
);
668 let msg_segv
= "clang: error: unable to execute command: Segmentation fault: 11";
669 let msg_bus
= "clang: error: unable to execute command: Bus error: 10";
670 if !(out
.contains(msg_segv
) || out
.contains(msg_bus
)) {
675 "looks like the linker segfaulted when we tried to call it, \
676 automatically retrying again. cmd = {:?}, out = {}.",
684 fn escape_string(s
: &[u8]) -> String
{
685 str::from_utf8(s
).map(|s
| s
.to_owned())
686 .unwrap_or_else(|_
| {
687 let mut x
= "Non-UTF-8 output: ".to_string();
689 .flat_map(|&b
| ascii
::escape_default(b
))
690 .map(|b
| char::from_u32(b
as u32).unwrap()));
694 if !prog
.status
.success() {
695 let mut output
= prog
.stderr
.clone();
696 output
.extend_from_slice(&prog
.stdout
);
697 sess
.struct_err(&format
!("linking with `{}` failed: {}",
700 .note(&format
!("{:?}", &cmd
))
701 .note(&escape_string(&output
))
703 sess
.abort_if_errors();
705 info
!("linker stderr:\n{}", escape_string(&prog
.stderr
));
706 info
!("linker stdout:\n{}", escape_string(&prog
.stdout
));
709 let linker_not_found
= e
.kind() == io
::ErrorKind
::NotFound
;
711 let mut linker_error
= {
712 if linker_not_found
{
713 sess
.struct_err(&format
!("linker `{}` not found", pname
.display()))
715 sess
.struct_err(&format
!("could not exec the linker `{}`", pname
.display()))
719 linker_error
.note(&format
!("{}", e
));
721 if !linker_not_found
{
722 linker_error
.note(&format
!("{:?}", &cmd
));
727 if sess
.target
.target
.options
.is_like_msvc
&& linker_not_found
{
728 sess
.note_without_error("the msvc targets depend on the msvc linker \
729 but `link.exe` was not found");
730 sess
.note_without_error("please ensure that VS 2013 or VS 2015 was installed \
731 with the Visual C++ option");
733 sess
.abort_if_errors();
738 // On macOS, debuggers need this utility to get run to do some munging of
740 if sess
.target
.target
.options
.is_like_osx
&& sess
.opts
.debuginfo
!= NoDebugInfo
{
741 match Command
::new("dsymutil").arg(out_filename
).output() {
743 Err(e
) => sess
.fatal(&format
!("failed to run dsymutil: {}", e
)),
748 fn exec_linker(sess
: &Session
, cmd
: &mut Command
, tmpdir
: &Path
)
749 -> io
::Result
<Output
>
751 // When attempting to spawn the linker we run a risk of blowing out the
752 // size limits for spawning a new process with respect to the arguments
753 // we pass on the command line.
755 // Here we attempt to handle errors from the OS saying "your list of
756 // arguments is too big" by reinvoking the linker again with an `@`-file
757 // that contains all the arguments. The theory is that this is then
758 // accepted on all linkers and the linker will read all its options out of
759 // there instead of looking at the command line.
760 if !cmd
.very_likely_to_exceed_some_spawn_limit() {
761 match cmd
.command().stdout(Stdio
::piped()).stderr(Stdio
::piped()).spawn() {
762 Ok(child
) => return child
.wait_with_output(),
763 Err(ref e
) if command_line_too_big(e
) => {}
764 Err(e
) => return Err(e
)
768 let mut cmd2
= cmd
.clone();
769 let mut args
= String
::new();
770 for arg
in cmd2
.take_args() {
771 args
.push_str(&Escape
{
772 arg
: arg
.to_str().unwrap(),
773 is_like_msvc
: sess
.target
.target
.options
.is_like_msvc
,
777 let file
= tmpdir
.join("linker-arguments");
778 let bytes
= if sess
.target
.target
.options
.is_like_msvc
{
779 let mut out
= vec
![];
780 // start the stream with a UTF-16 BOM
781 for c
in vec
![0xFEFF].into_iter().chain(args
.encode_utf16()) {
782 // encode in little endian
784 out
.push((c
>> 8) as u8);
790 fs
::write(&file
, &bytes
)?
;
791 cmd2
.arg(format
!("@{}", file
.display()));
792 return cmd2
.output();
795 fn command_line_too_big(err
: &io
::Error
) -> bool
{
796 err
.raw_os_error() == Some(::libc
::E2BIG
)
800 fn command_line_too_big(err
: &io
::Error
) -> bool
{
801 const ERROR_FILENAME_EXCED_RANGE
: i32 = 206;
802 err
.raw_os_error() == Some(ERROR_FILENAME_EXCED_RANGE
)
810 impl<'a
> fmt
::Display
for Escape
<'a
> {
811 fn fmt(&self, f
: &mut fmt
::Formatter
) -> fmt
::Result
{
812 if self.is_like_msvc
{
813 // This is "documented" at
814 // https://msdn.microsoft.com/en-us/library/4xdcbak7.aspx
816 // Unfortunately there's not a great specification of the
817 // syntax I could find online (at least) but some local
818 // testing showed that this seemed sufficient-ish to catch
819 // at least a few edge cases.
821 for c
in self.arg
.chars() {
823 '
"' => write!(f, "\\{}
", c)?,
824 c => write!(f, "{}
", c)?,
829 // This is documented at https://linux.die.net/man/1/ld, namely:
831 // > Options in file are separated by whitespace. A whitespace
832 // > character may be included in an option by surrounding the
833 // > entire option in either single or double quotes. Any
834 // > character (including a backslash) may be included by
835 // > prefixing the character to be included with a backslash.
837 // We put an argument on each line, so all we need to do is
838 // ensure the line is interpreted as one whole argument.
839 for c in self.arg.chars() {
842 ' ' => write!(f, "\\{}
", c)?,
843 c => write!(f, "{}
", c)?,
852 fn link_args(cmd: &mut Linker,
854 crate_type: config::CrateType,
857 trans: &CrateTranslation) {
859 // The default library location, we need this to find the runtime.
860 // The location of crates will be determined as needed.
861 let lib_path = sess.target_filesearch(PathKind::All).get_lib_path();
864 let t = &sess.target.target;
866 cmd.include_path(&fix_windows_verbatim_for_gcc(&lib_path));
867 for obj in trans.modules.iter().filter_map(|m| m.object.as_ref()) {
870 cmd.output_filename(out_filename);
872 if crate_type == config::CrateTypeExecutable &&
873 sess.target.target.options.is_like_windows {
874 if let Some(ref s) = trans.windows_subsystem {
879 // If we're building a dynamic library then some platforms need to make sure
880 // that all symbols are exported correctly from the dynamic library.
881 if crate_type != config::CrateTypeExecutable ||
882 sess.target.target.options.is_like_emscripten {
883 cmd.export_symbols(tmpdir, crate_type);
886 // When linking a dynamic library, we put the metadata into a section of the
887 // executable. This metadata is in a separate object file from the main
888 // object file, so we link that in here.
889 if crate_type == config::CrateTypeDylib ||
890 crate_type == config::CrateTypeProcMacro {
891 if let Some(obj) = trans.metadata_module.object.as_ref() {
896 let obj = trans.allocator_module
898 .and_then(|m| m.object.as_ref());
899 if let Some(obj) = obj {
903 // Try to strip as much out of the generated object by removing unused
904 // sections if possible. See more comments in linker.rs
905 if !sess.opts.cg.link_dead_code {
906 let keep_metadata = crate_type == config::CrateTypeDylib;
907 cmd.gc_sections(keep_metadata);
910 let used_link_args = &trans.crate_info.link_args;
912 if crate_type == config::CrateTypeExecutable &&
913 t.options.position_independent_executables {
914 let empty_vec = Vec::new();
915 let args = sess.opts.cg.link_args.as_ref().unwrap_or(&empty_vec);
916 let more_args = &sess.opts.cg.link_arg;
917 let mut args = args.iter().chain(more_args.iter()).chain(used_link_args.iter());
919 if get_reloc_model(sess) == llvm::RelocMode::PIC
920 && !sess.crt_static() && !args.any(|x| *x == "-static") {
921 cmd.position_independent_executable();
925 let relro_level = match sess.opts.debugging_opts.relro_level {
926 Some(level) => level,
927 None => t.options.relro_level,
930 RelroLevel::Full => {
933 RelroLevel::Partial => {
936 RelroLevel::Off => {},
939 // Pass optimization flags down to the linker.
942 // Pass debuginfo flags down to the linker.
945 // We want to prevent the compiler from accidentally leaking in any system
946 // libraries, so we explicitly ask gcc to not link to any libraries by
947 // default. Note that this does not happen for windows because windows pulls
948 // in some large number of libraries and I couldn't quite figure out which
950 if t.options.no_default_libraries {
951 cmd.no_default_libraries();
954 // Take careful note of the ordering of the arguments we pass to the linker
955 // here. Linkers will assume that things on the left depend on things to the
956 // right. Things on the right cannot depend on things on the left. This is
957 // all formally implemented in terms of resolving symbols (libs on the right
958 // resolve unknown symbols of libs on the left, but not vice versa).
960 // For this reason, we have organized the arguments we pass to the linker as
963 // 1. The local object that LLVM just generated
964 // 2. Local native libraries
965 // 3. Upstream rust libraries
966 // 4. Upstream native libraries
968 // The rationale behind this ordering is that those items lower down in the
969 // list can't depend on items higher up in the list. For example nothing can
970 // depend on what we just generated (e.g. that'd be a circular dependency).
971 // Upstream rust libraries are not allowed to depend on our local native
972 // libraries as that would violate the structure of the DAG, in that
973 // scenario they are required to link to them as well in a shared fashion.
975 // Note that upstream rust libraries may contain native dependencies as
976 // well, but they also can't depend on what we just started to add to the
977 // link line. And finally upstream native libraries can't depend on anything
978 // in this DAG so far because they're only dylibs and dylibs can only depend
979 // on other dylibs (e.g. other native deps).
980 add_local_native_libraries(cmd, sess, trans);
981 add_upstream_rust_crates(cmd, sess, trans, crate_type, tmpdir);
982 add_upstream_native_libraries(cmd, sess, trans, crate_type);
984 // Tell the linker what we're doing.
985 if crate_type != config::CrateTypeExecutable {
986 cmd.build_dylib(out_filename);
988 if crate_type == config::CrateTypeExecutable && sess.crt_static() {
989 cmd.build_static_executable();
992 // FIXME (#2397): At some point we want to rpath our guesses as to
993 // where extern libraries might live, based on the
994 // addl_lib_search_paths
995 if sess.opts.cg.rpath {
996 let sysroot = sess.sysroot();
997 let target_triple = &sess.opts.target_triple;
998 let mut get_install_prefix_lib_path = || {
999 let install_prefix = option_env!("CFG_PREFIX
").expect("CFG_PREFIX
");
1000 let tlib = filesearch::relative_target_lib_path(sysroot, target_triple);
1001 let mut path = PathBuf::from(install_prefix);
1006 let mut rpath_config = RPathConfig {
1007 used_crates: &trans.crate_info.used_crates_dynamic,
1008 out_filename: out_filename.to_path_buf(),
1009 has_rpath: sess.target.target.options.has_rpath,
1010 is_like_osx: sess.target.target.options.is_like_osx,
1011 linker_is_gnu: sess.target.target.options.linker_is_gnu,
1012 get_install_prefix_lib_path: &mut get_install_prefix_lib_path,
1014 cmd.args(&rpath::get_rpath_flags(&mut rpath_config));
1017 // Finally add all the linker arguments provided on the command line along
1018 // with any #[link_args] attributes found inside the crate
1019 if let Some(ref args) = sess.opts.cg.link_args {
1022 cmd.args(&sess.opts.cg.link_arg);
1023 cmd.args(&used_link_args);
1026 // # Native library linking
1028 // User-supplied library search paths (-L on the command line). These are
1029 // the same paths used to find Rust crates, so some of them may have been
1030 // added already by the previous crate linking code. This only allows them
1031 // to be found at compile time so it is still entirely up to outside
1032 // forces to make sure that library can be found at runtime.
1034 // Also note that the native libraries linked here are only the ones located
1035 // in the current crate. Upstream crates with native library dependencies
1036 // may have their native library pulled in above.
1037 fn add_local_native_libraries(cmd: &mut Linker,
1039 trans: &CrateTranslation) {
1040 sess.target_filesearch(PathKind::All).for_each_lib_search_path(|path, k| {
1042 PathKind::Framework => { cmd.framework_path(path); }
1043 _ => { cmd.include_path(&fix_windows_verbatim_for_gcc(path)); }
1047 let relevant_libs = trans.crate_info.used_libraries.iter().filter(|l| {
1048 relevant_lib(sess, l)
1051 let search_path = archive_search_paths(sess);
1052 for lib in relevant_libs {
1054 NativeLibraryKind::NativeUnknown => cmd.link_dylib(&lib.name.as_str()),
1055 NativeLibraryKind::NativeFramework => cmd.link_framework(&lib.name.as_str()),
1056 NativeLibraryKind::NativeStaticNobundle => cmd.link_staticlib(&lib.name.as_str()),
1057 NativeLibraryKind::NativeStatic => cmd.link_whole_staticlib(&lib.name.as_str(),
1063 // # Rust Crate linking
1065 // Rust crates are not considered at all when creating an rlib output. All
1066 // dependencies will be linked when producing the final output (instead of
1067 // the intermediate rlib version)
1068 fn add_upstream_rust_crates(cmd: &mut Linker,
1070 trans: &CrateTranslation,
1071 crate_type: config::CrateType,
1073 // All of the heavy lifting has previously been accomplished by the
1074 // dependency_format module of the compiler. This is just crawling the
1075 // output of that module, adding crates as necessary.
1077 // Linking to a rlib involves just passing it to the linker (the linker
1078 // will slurp up the object files inside), and linking to a dynamic library
1079 // involves just passing the right -l flag.
1081 let formats = sess.dependency_formats.borrow();
1082 let data = formats.get(&crate_type).unwrap();
1084 // Invoke get_used_crates to ensure that we get a topological sorting of
1086 let deps = &trans.crate_info.used_crates_dynamic;
1088 let mut compiler_builtins = None;
1090 for &(cnum, _) in deps.iter() {
1091 // We may not pass all crates through to the linker. Some crates may
1092 // appear statically in an existing dylib, meaning we'll pick up all the
1093 // symbols from the dylib.
1094 let src = &trans.crate_info.used_crate_source[&cnum];
1095 match data[cnum.as_usize() - 1] {
1096 _ if trans.crate_info.profiler_runtime == Some(cnum) => {
1097 add_static_crate(cmd, sess, trans, tmpdir, crate_type, cnum);
1099 _ if trans.crate_info.sanitizer_runtime == Some(cnum) => {
1100 link_sanitizer_runtime(cmd, sess, trans, tmpdir, cnum);
1102 // compiler-builtins are always placed last to ensure that they're
1103 // linked correctly.
1104 _ if trans.crate_info.compiler_builtins == Some(cnum) => {
1105 assert!(compiler_builtins.is_none());
1106 compiler_builtins = Some(cnum);
1108 Linkage::NotLinked |
1109 Linkage::IncludedFromDylib => {}
1110 Linkage::Static => {
1111 add_static_crate(cmd, sess, trans, tmpdir, crate_type, cnum);
1113 Linkage::Dynamic => {
1114 add_dynamic_crate(cmd, sess, &src.dylib.as_ref().unwrap().0)
1119 // compiler-builtins are always placed last to ensure that they're
1120 // linked correctly.
1121 // We must always link the `compiler_builtins` crate statically. Even if it
1122 // was already "included
" in a dylib (e.g. `libstd` when `-C prefer-dynamic`
1124 if let Some(cnum) = compiler_builtins {
1125 add_static_crate(cmd, sess, trans, tmpdir, crate_type, cnum);
1128 // Converts a library file-stem into a cc -l argument
1129 fn unlib<'a>(config: &config::Config, stem: &'a str) -> &'a str {
1130 if stem.starts_with("lib
") && !config.target.options.is_like_windows {
1137 // We must link the sanitizer runtime using -Wl,--whole-archive but since
1138 // it's packed in a .rlib, it contains stuff that are not objects that will
1139 // make the linker error. So we must remove those bits from the .rlib before
1141 fn link_sanitizer_runtime(cmd: &mut Linker,
1143 trans: &CrateTranslation,
1146 let src = &trans.crate_info.used_crate_source[&cnum];
1147 let cratepath = &src.rlib.as_ref().unwrap().0;
1149 if sess.target.target.options.is_like_osx {
1150 // On Apple platforms, the sanitizer is always built as a dylib, and
1151 // LLVM will link to `@rpath/*.dylib`, so we need to specify an
1152 // rpath to the library as well (the rpath should be absolute, see
1153 // PR #41352 for details).
1155 // FIXME: Remove this logic into librustc_*san once Cargo supports it
1156 let rpath = cratepath.parent().unwrap();
1157 let rpath = rpath.to_str().expect("non
-utf8 component
in path
");
1158 cmd.args(&["-Wl
,-rpath
".into(), "-Xlinker
".into(), rpath.into()]);
1161 let dst = tmpdir.join(cratepath.file_name().unwrap());
1162 let cfg = archive_config(sess, &dst, Some(cratepath));
1163 let mut archive = ArchiveBuilder::new(cfg);
1164 archive.update_symbols();
1166 for f in archive.src_files() {
1167 if f.ends_with(RLIB_BYTECODE_EXTENSION) || f == METADATA_FILENAME {
1168 archive.remove_file(&f);
1175 cmd.link_whole_rlib(&dst);
1178 // Adds the static "rlib
" versions of all crates to the command line.
1179 // There's a bit of magic which happens here specifically related to LTO and
1180 // dynamic libraries. Specifically:
1182 // * For LTO, we remove upstream object files.
1183 // * For dylibs we remove metadata and bytecode from upstream rlibs
1185 // When performing LTO, almost(*) all of the bytecode from the upstream
1186 // libraries has already been included in our object file output. As a
1187 // result we need to remove the object files in the upstream libraries so
1188 // the linker doesn't try to include them twice (or whine about duplicate
1189 // symbols). We must continue to include the rest of the rlib, however, as
1190 // it may contain static native libraries which must be linked in.
1192 // (*) Crates marked with `#![no_builtins]` don't participate in LTO and
1193 // their bytecode wasn't included. The object files in those libraries must
1194 // still be passed to the linker.
1196 // When making a dynamic library, linkers by default don't include any
1197 // object files in an archive if they're not necessary to resolve the link.
1198 // We basically want to convert the archive (rlib) to a dylib, though, so we
1199 // *do* want everything included in the output, regardless of whether the
1200 // linker thinks it's needed or not. As a result we must use the
1201 // --whole-archive option (or the platform equivalent). When using this
1202 // option the linker will fail if there are non-objects in the archive (such
1203 // as our own metadata and/or bytecode). All in all, for rlibs to be
1204 // entirely included in dylibs, we need to remove all non-object files.
1206 // Note, however, that if we're not doing LTO or we're not producing a dylib
1207 // (aka we're making an executable), we can just pass the rlib blindly to
1208 // the linker (fast) because it's fine if it's not actually included as
1209 // we're at the end of the dependency chain.
1210 fn add_static_crate(cmd: &mut Linker,
1212 trans: &CrateTranslation,
1214 crate_type: config::CrateType,
1216 let src = &trans.crate_info.used_crate_source[&cnum];
1217 let cratepath = &src.rlib.as_ref().unwrap().0;
1219 // See the comment above in `link_staticlib` and `link_rlib` for why if
1220 // there's a static library that's not relevant we skip all object
1222 let native_libs = &trans.crate_info.native_libraries[&cnum];
1223 let skip_native = native_libs.iter().any(|lib| {
1224 lib.kind == NativeLibraryKind::NativeStatic && !relevant_lib(sess, lib)
1227 if (!is_full_lto_enabled(sess) ||
1228 ignored_for_lto(sess, &trans.crate_info, cnum)) &&
1229 crate_type != config::CrateTypeDylib &&
1231 cmd.link_rlib(&fix_windows_verbatim_for_gcc(cratepath));
1235 let dst = tmpdir.join(cratepath.file_name().unwrap());
1236 let name = cratepath.file_name().unwrap().to_str().unwrap();
1237 let name = &name[3..name.len() - 5]; // chop off lib/.rlib
1239 time(sess.time_passes(), &format!("altering {}
.rlib
", name), || {
1240 let cfg = archive_config(sess, &dst, Some(cratepath));
1241 let mut archive = ArchiveBuilder::new(cfg);
1242 archive.update_symbols();
1244 let mut any_objects = false;
1245 for f in archive.src_files() {
1246 if f.ends_with(RLIB_BYTECODE_EXTENSION) || f == METADATA_FILENAME {
1247 archive.remove_file(&f);
1251 let canonical = f.replace("-", "_
");
1252 let canonical_name = name.replace("-", "_
");
1254 // Look for `.rcgu.o` at the end of the filename to conclude
1255 // that this is a Rust-related object file.
1256 fn looks_like_rust(s: &str) -> bool {
1257 let path = Path::new(s);
1258 let ext = path.extension().and_then(|s| s.to_str());
1259 if ext != Some(OutputType::Object.extension()) {
1262 let ext2 = path.file_stem()
1263 .and_then(|s| Path::new(s).extension())
1264 .and_then(|s| s.to_str());
1265 ext2 == Some(RUST_CGU_EXT)
1268 let is_rust_object =
1269 canonical.starts_with(&canonical_name) &&
1270 looks_like_rust(&f);
1272 // If we've been requested to skip all native object files
1273 // (those not generated by the rust compiler) then we can skip
1274 // this file. See above for why we may want to do this.
1275 let skip_because_cfg_say_so = skip_native && !is_rust_object;
1277 // If we're performing LTO and this is a rust-generated object
1278 // file, then we don't need the object file as it's part of the
1279 // LTO module. Note that `#![no_builtins]` is excluded from LTO,
1280 // though, so we let that object file slide.
1281 let skip_because_lto = is_full_lto_enabled(sess) &&
1283 (sess.target.target.options.no_builtins ||
1284 !trans.crate_info.is_no_builtins.contains(&cnum));
1286 if skip_because_cfg_say_so || skip_because_lto {
1287 archive.remove_file(&f);
1298 // If we're creating a dylib, then we need to include the
1299 // whole of each object in our archive into that artifact. This is
1300 // because a `dylib` can be reused as an intermediate artifact.
1302 // Note, though, that we don't want to include the whole of a
1303 // compiler-builtins crate (e.g. compiler-rt) because it'll get
1304 // repeatedly linked anyway.
1305 if crate_type == config::CrateTypeDylib &&
1306 trans.crate_info.compiler_builtins != Some(cnum) {
1307 cmd.link_whole_rlib(&fix_windows_verbatim_for_gcc(&dst));
1309 cmd.link_rlib(&fix_windows_verbatim_for_gcc(&dst));
1314 // Same thing as above, but for dynamic crates instead of static crates.
1315 fn add_dynamic_crate(cmd: &mut Linker, sess: &Session, cratepath: &Path) {
1316 // If we're performing LTO, then it should have been previously required
1317 // that all upstream rust dependencies were available in an rlib format.
1318 assert!(!is_full_lto_enabled(sess));
1320 // Just need to tell the linker about where the library lives and
1322 let parent = cratepath.parent();
1323 if let Some(dir) = parent {
1324 cmd.include_path(&fix_windows_verbatim_for_gcc(dir));
1326 let filestem = cratepath.file_stem().unwrap().to_str().unwrap();
1327 cmd.link_rust_dylib(&unlib(&sess.target, filestem),
1328 parent.unwrap_or(Path::new("")));
1332 // Link in all of our upstream crates' native dependencies. Remember that
1333 // all of these upstream native dependencies are all non-static
1334 // dependencies. We've got two cases then:
1336 // 1. The upstream crate is an rlib. In this case we *must* link in the
1337 // native dependency because the rlib is just an archive.
1339 // 2. The upstream crate is a dylib. In order to use the dylib, we have to
1340 // have the dependency present on the system somewhere. Thus, we don't
1341 // gain a whole lot from not linking in the dynamic dependency to this
1344 // The use case for this is a little subtle. In theory the native
1345 // dependencies of a crate are purely an implementation detail of the crate
1346 // itself, but the problem arises with generic and inlined functions. If a
1347 // generic function calls a native function, then the generic function must
1348 // be instantiated in the target crate, meaning that the native symbol must
1349 // also be resolved in the target crate.
1350 fn add_upstream_native_libraries(cmd: &mut Linker,
1352 trans: &CrateTranslation,
1353 crate_type: config::CrateType) {
1354 // Be sure to use a topological sorting of crates because there may be
1355 // interdependencies between native libraries. When passing -nodefaultlibs,
1356 // for example, almost all native libraries depend on libc, so we have to
1357 // make sure that's all the way at the right (liblibc is near the base of
1358 // the dependency chain).
1360 // This passes RequireStatic, but the actual requirement doesn't matter,
1361 // we're just getting an ordering of crate numbers, we're not worried about
1363 let formats = sess.dependency_formats.borrow();
1364 let data = formats.get(&crate_type).unwrap();
1366 let crates = &trans.crate_info.used_crates_static;
1367 for &(cnum, _) in crates {
1368 for lib in trans.crate_info.native_libraries[&cnum].iter() {
1369 if !relevant_lib(sess, &lib) {
1373 NativeLibraryKind::NativeUnknown => cmd.link_dylib(&lib.name.as_str()),
1374 NativeLibraryKind::NativeFramework => cmd.link_framework(&lib.name.as_str()),
1375 NativeLibraryKind::NativeStaticNobundle => {
1376 // Link "static-nobundle
" native libs only if the crate they originate from
1377 // is being linked statically to the current crate. If it's linked dynamically
1378 // or is an rlib already included via some other dylib crate, the symbols from
1379 // native libs will have already been included in that dylib.
1380 if data[cnum.as_usize() - 1] == Linkage::Static {
1381 cmd.link_staticlib(&lib.name.as_str())
1384 // ignore statically included native libraries here as we've
1385 // already included them when we included the rust library
1387 NativeLibraryKind::NativeStatic => {}
1393 fn relevant_lib(sess: &Session, lib: &NativeLibrary) -> bool {
1395 Some(ref cfg) => attr::cfg_matches(cfg, &sess.parse_sess, None),
1400 /// For now "linking with binaryen
" is just "move the one module we generated
in
1401 /// the backend to the final output"
1403 /// That is, all the heavy lifting happens during the `back::write` phase. Here
1404 /// we just clean up after that.
1406 /// Note that this is super temporary and "will not survive the night", this is
1407 /// guaranteed to get removed as soon as a linker for wasm exists. This should
1408 /// not be used for anything other than wasm.
1409 fn link_binaryen(sess
: &Session
,
1410 _crate_type
: config
::CrateType
,
1411 out_filename
: &Path
,
1412 trans
: &CrateTranslation
,
1414 assert
!(trans
.allocator_module
.is_none());
1415 assert_eq
!(trans
.modules
.len(), 1);
1417 let object
= trans
.modules
[0].object
.as_ref().expect("object must exist");
1418 let res
= fs
::hard_link(object
, out_filename
)
1419 .or_else(|_
| fs
::copy(object
, out_filename
).map(|_
| ()));
1420 if let Err(e
) = res
{
1421 sess
.fatal(&format
!("failed to create `{}`: {}",
1422 out_filename
.display(),
1427 fn is_full_lto_enabled(sess
: &Session
) -> bool
{
1433 Lto
::ThinLocal
=> false,