1 use super::command::Command;
2 use super::symbol_export;
3 use crate::errors::LibDefWriteFailure;
4 use rustc_span::symbol::sym;
6 use std::ffi::{OsStr, OsString};
7 use std::fs::{self, File};
8 use std::io::prelude::*;
9 use std::io::{self, BufWriter};
10 use std::path::{Path, PathBuf};
11 use std::{env, mem, str};
13 use rustc_hir::def_id::{CrateNum, LOCAL_CRATE};
14 use rustc_metadata::find_native_static_library;
15 use rustc_middle::middle::dependency_format::Linkage;
16 use rustc_middle::middle::exported_symbols::{ExportedSymbol, SymbolExportInfo, SymbolExportKind};
17 use rustc_middle::ty::TyCtxt;
18 use rustc_session::config::{self, CrateType, DebugInfo, LinkerPluginLto, Lto, OptLevel, Strip};
19 use rustc_session::Session;
20 use rustc_target::spec::{Cc, LinkOutputKind, LinkerFlavor, Lld};
22 use cc::windows_registry;
24 /// Disables non-English messages from localized linkers.
25 /// Such messages may cause issues with text encoding on Windows (#35785)
26 /// and prevent inspection of linker output in case of errors, which we occasionally do.
27 /// This should be acceptable because other messages from rustc are in English anyway,
28 /// and may also be desirable to improve searchability of the linker diagnostics.
29 pub fn disable_localization(linker: &mut Command) {
30 // No harm in setting both env vars simultaneously.
31 // Unix-style linkers.
32 linker.env("LC_ALL", "C");
34 linker.env("VSLANG", "1033");
37 // The third parameter is for env vars, used on windows to set up the
38 // path for MSVC to find its DLLs, and gcc to find its bundled
40 pub fn get_linker<'a>(
46 ) -> Box<dyn Linker + 'a> {
47 let msvc_tool = windows_registry::find_tool(&sess.opts.target_triple.triple(), "link.exe");
49 // If our linker looks like a batch script on Windows then to execute this
50 // we'll need to spawn `cmd` explicitly. This is primarily done to handle
51 // emscripten where the linker is `emcc.bat` and needs to be spawned as
52 // `cmd /c emcc.bat ...`.
54 // This worked historically but is needed manually since #42436 (regression
55 // was tagged as #42791) and some more info can be found on #44443 for
57 let mut cmd = match linker.to_str() {
58 Some(linker) if cfg!(windows) && linker.ends_with(".bat") => Command::bat_script(linker),
60 LinkerFlavor::Gnu(Cc::No, Lld::Yes)
61 | LinkerFlavor::Darwin(Cc::No, Lld::Yes)
62 | LinkerFlavor::WasmLld(Cc::No)
63 | LinkerFlavor::Msvc(Lld::Yes) => Command::lld(linker, flavor.lld_flavor()),
64 LinkerFlavor::Msvc(Lld::No)
65 if sess.opts.cg.linker.is_none() && sess.target.linker.is_none() =>
67 Command::new(msvc_tool.as_ref().map_or(linker, |t| t.path()))
69 _ => Command::new(linker),
73 // UWP apps have API restrictions enforced during Store submissions.
74 // To comply with the Windows App Certification Kit,
75 // MSVC needs to link with the Store versions of the runtime libraries (vcruntime, msvcrt, etc).
77 if matches!(flavor, LinkerFlavor::Msvc(..)) && t.vendor == "uwp" {
78 if let Some(ref tool) = msvc_tool {
79 let original_path = tool.path();
80 if let Some(ref root_lib_path) = original_path.ancestors().nth(4) {
81 let arch = match t.arch.as_ref() {
82 "x86_64" => Some("x64"),
84 "aarch64" => Some("arm64"),
88 if let Some(ref a) = arch {
89 // FIXME: Move this to `fn linker_with_args`.
90 let mut arg = OsString::from("/LIBPATH:");
91 arg.push(format!("{}\\lib\\{}\\store", root_lib_path.display(), a));
94 warn!("arch is not supported");
97 warn!("MSVC root path lib location not found");
100 warn!("link.exe not found");
104 // The compiler's sysroot often has some bundled tools, so add it to the
105 // PATH for the child.
106 let mut new_path = sess.get_tools_search_paths(self_contained);
107 let mut msvc_changed_path = false;
108 if sess.target.is_like_msvc {
109 if let Some(ref tool) = msvc_tool {
110 cmd.args(tool.args());
111 for &(ref k, ref v) in tool.env() {
113 new_path.extend(env::split_paths(v));
114 msvc_changed_path = true;
122 if !msvc_changed_path {
123 if let Some(path) = env::var_os("PATH") {
124 new_path.extend(env::split_paths(&path));
127 cmd.env("PATH", env::join_paths(new_path).unwrap());
129 // FIXME: Move `/LIBPATH` addition for uwp targets from the linker construction
130 // to the linker args construction.
131 assert!(cmd.get_args().is_empty() || sess.target.vendor == "uwp");
133 LinkerFlavor::Unix(Cc::No) if sess.target.os == "l4re" => {
134 Box::new(L4Bender::new(cmd, sess)) as Box<dyn Linker>
136 LinkerFlavor::WasmLld(Cc::No) => Box::new(WasmLd::new(cmd, sess)) as Box<dyn Linker>,
137 LinkerFlavor::Gnu(cc, _)
138 | LinkerFlavor::Darwin(cc, _)
139 | LinkerFlavor::WasmLld(cc)
140 | LinkerFlavor::Unix(cc) => Box::new(GccLinker {
144 hinted_static: false,
146 is_gnu: flavor.is_gnu(),
147 }) as Box<dyn Linker>,
148 LinkerFlavor::Msvc(..) => Box::new(MsvcLinker { cmd, sess }) as Box<dyn Linker>,
149 LinkerFlavor::EmCc => Box::new(EmLinker { cmd, sess }) as Box<dyn Linker>,
150 LinkerFlavor::Bpf => Box::new(BpfLinker { cmd, sess }) as Box<dyn Linker>,
151 LinkerFlavor::Ptx => Box::new(PtxLinker { cmd, sess }) as Box<dyn Linker>,
155 /// Linker abstraction used by `back::link` to build up the command to invoke a
158 /// This trait is the total list of requirements needed by `back::link` and
159 /// represents the meaning of each option being passed down. This trait is then
160 /// used to dispatch on whether a GNU-like linker (generally `ld.exe`) or an
161 /// MSVC linker (e.g., `link.exe`) is being used.
163 fn cmd(&mut self) -> &mut Command;
164 fn set_output_kind(&mut self, output_kind: LinkOutputKind, out_filename: &Path);
165 fn link_dylib(&mut self, lib: &str, verbatim: bool, as_needed: bool);
166 fn link_rust_dylib(&mut self, lib: &str, path: &Path);
167 fn link_framework(&mut self, framework: &str, as_needed: bool);
168 fn link_staticlib(&mut self, lib: &str, verbatim: bool);
169 fn link_rlib(&mut self, lib: &Path);
170 fn link_whole_rlib(&mut self, lib: &Path);
171 fn link_whole_staticlib(&mut self, lib: &str, verbatim: bool, search_path: &[PathBuf]);
172 fn include_path(&mut self, path: &Path);
173 fn framework_path(&mut self, path: &Path);
174 fn output_filename(&mut self, path: &Path);
175 fn add_object(&mut self, path: &Path);
176 fn gc_sections(&mut self, keep_metadata: bool);
177 fn no_gc_sections(&mut self);
178 fn full_relro(&mut self);
179 fn partial_relro(&mut self);
180 fn no_relro(&mut self);
181 fn optimize(&mut self);
182 fn pgo_gen(&mut self);
183 fn control_flow_guard(&mut self);
184 fn debuginfo(&mut self, strip: Strip, natvis_debugger_visualizers: &[PathBuf]);
185 fn no_crt_objects(&mut self);
186 fn no_default_libraries(&mut self);
187 fn export_symbols(&mut self, tmpdir: &Path, crate_type: CrateType, symbols: &[String]);
188 fn subsystem(&mut self, subsystem: &str);
189 fn linker_plugin_lto(&mut self);
190 fn add_eh_frame_header(&mut self) {}
191 fn add_no_exec(&mut self) {}
192 fn add_as_needed(&mut self) {}
193 fn reset_per_library_state(&mut self) {}
196 impl dyn Linker + '_ {
197 pub fn arg(&mut self, arg: impl AsRef<OsStr>) {
201 pub fn args(&mut self, args: impl IntoIterator<Item: AsRef<OsStr>>) {
202 self.cmd().args(args);
205 pub fn take_cmd(&mut self) -> Command {
206 mem::replace(self.cmd(), Command::new(""))
210 pub struct GccLinker<'a> {
214 hinted_static: bool, // Keeps track of the current hinting mode.
220 impl<'a> GccLinker<'a> {
221 /// Passes an argument directly to the linker.
223 /// When the linker is not ld-like such as when using a compiler as a linker, the argument is
224 /// prepended by `-Wl,`.
225 fn linker_arg(&mut self, arg: impl AsRef<OsStr>) -> &mut Self {
226 self.linker_args(&[arg]);
230 /// Passes a series of arguments directly to the linker.
232 /// When the linker is ld-like, the arguments are simply appended to the command. When the
233 /// linker is not ld-like such as when using a compiler as a linker, the arguments are joined by
234 /// commas to form an argument that is then prepended with `-Wl`. In this situation, only a
235 /// single argument is appended to the command to ensure that the order of the arguments is
236 /// preserved by the compiler.
237 fn linker_args(&mut self, args: &[impl AsRef<OsStr>]) -> &mut Self {
239 args.into_iter().for_each(|a| {
243 if !args.is_empty() {
244 let mut s = OsString::from("-Wl");
255 fn takes_hints(&self) -> bool {
256 // Really this function only returns true if the underlying linker
257 // configured for a compiler is binutils `ld.bfd` and `ld.gold`. We
258 // don't really have a foolproof way to detect that, so rule out some
259 // platforms where currently this is guaranteed to *not* be the case:
261 // * On OSX they have their own linker, not binutils'
262 // * For WebAssembly the only functional linker is LLD, which doesn't
263 // support hint flags
264 !self.sess.target.is_like_osx && !self.sess.target.is_like_wasm
267 // Some platforms take hints about whether a library is static or dynamic.
268 // For those that support this, we ensure we pass the option if the library
269 // was flagged "static" (most defaults are dynamic) to ensure that if
270 // libfoo.a and libfoo.so both exist that the right one is chosen.
271 fn hint_static(&mut self) {
272 if !self.takes_hints() {
275 if !self.hinted_static {
276 self.linker_arg("-Bstatic");
277 self.hinted_static = true;
281 fn hint_dynamic(&mut self) {
282 if !self.takes_hints() {
285 if self.hinted_static {
286 self.linker_arg("-Bdynamic");
287 self.hinted_static = false;
291 fn push_linker_plugin_lto_args(&mut self, plugin_path: Option<&OsStr>) {
292 if let Some(plugin_path) = plugin_path {
293 let mut arg = OsString::from("-plugin=");
294 arg.push(plugin_path);
295 self.linker_arg(&arg);
298 let opt_level = match self.sess.opts.optimize {
299 config::OptLevel::No => "O0",
300 config::OptLevel::Less => "O1",
301 config::OptLevel::Default | config::OptLevel::Size | config::OptLevel::SizeMin => "O2",
302 config::OptLevel::Aggressive => "O3",
305 if let Some(path) = &self.sess.opts.unstable_opts.profile_sample_use {
306 self.linker_arg(&format!("-plugin-opt=sample-profile={}", path.display()));
309 &format!("-plugin-opt={}", opt_level),
310 &format!("-plugin-opt=mcpu={}", self.target_cpu),
314 fn build_dylib(&mut self, out_filename: &Path) {
315 // On mac we need to tell the linker to let this library be rpathed
316 if self.sess.target.is_like_osx {
318 self.cmd.arg("-dynamiclib");
321 self.linker_arg("-dylib");
323 // Note that the `osx_rpath_install_name` option here is a hack
324 // purely to support rustbuild right now, we should get a more
325 // principled solution at some point to force the compiler to pass
326 // the right `-Wl,-install_name` with an `@rpath` in it.
327 if self.sess.opts.cg.rpath || self.sess.opts.unstable_opts.osx_rpath_install_name {
328 let mut rpath = OsString::from("@rpath/");
329 rpath.push(out_filename.file_name().unwrap());
330 self.linker_args(&[OsString::from("-install_name"), rpath]);
333 self.cmd.arg("-shared");
334 if self.sess.target.is_like_windows {
335 // The output filename already contains `dll_suffix` so
336 // the resulting import library will have a name in the
337 // form of libfoo.dll.a
339 out_filename.file_name().and_then(|file| file.to_str()).map(|file| {
342 self.sess.target.staticlib_prefix,
344 self.sess.target.staticlib_suffix
347 if let Some(implib_name) = implib_name {
348 let implib = out_filename.parent().map(|dir| dir.join(&implib_name));
349 if let Some(implib) = implib {
350 self.linker_arg(&format!("--out-implib={}", (*implib).to_str().unwrap()));
358 impl<'a> Linker for GccLinker<'a> {
359 fn cmd(&mut self) -> &mut Command {
363 fn set_output_kind(&mut self, output_kind: LinkOutputKind, out_filename: &Path) {
365 LinkOutputKind::DynamicNoPicExe => {
366 if !self.is_ld && self.is_gnu {
367 self.cmd.arg("-no-pie");
370 LinkOutputKind::DynamicPicExe => {
371 // noop on windows w/ gcc & ld, error w/ lld
372 if !self.sess.target.is_like_windows {
373 // `-pie` works for both gcc wrapper and ld.
374 self.cmd.arg("-pie");
377 LinkOutputKind::StaticNoPicExe => {
378 // `-static` works for both gcc wrapper and ld.
379 self.cmd.arg("-static");
380 if !self.is_ld && self.is_gnu {
381 self.cmd.arg("-no-pie");
384 LinkOutputKind::StaticPicExe => {
386 // Note that combination `-static -pie` doesn't work as expected
387 // for the gcc wrapper, `-static` in that case suppresses `-pie`.
388 self.cmd.arg("-static-pie");
390 // `--no-dynamic-linker` and `-z text` are not strictly necessary for producing
391 // a static pie, but currently passed because gcc and clang pass them.
392 // The former suppresses the `INTERP` ELF header specifying dynamic linker,
393 // which is otherwise implicitly injected by ld (but not lld).
394 // The latter doesn't change anything, only ensures that everything is pic.
395 self.cmd.args(&["-static", "-pie", "--no-dynamic-linker", "-z", "text"]);
398 LinkOutputKind::DynamicDylib => self.build_dylib(out_filename),
399 LinkOutputKind::StaticDylib => {
400 self.cmd.arg("-static");
401 self.build_dylib(out_filename);
403 LinkOutputKind::WasiReactorExe => {
404 self.linker_args(&["--entry", "_initialize"]);
407 // VxWorks compiler driver introduced `--static-crt` flag specifically for rustc,
408 // it switches linking for libc and similar system libraries to static without using
409 // any `#[link]` attributes in the `libc` crate, see #72782 for details.
410 // FIXME: Switch to using `#[link]` attributes in the `libc` crate
411 // similarly to other targets.
412 if self.sess.target.os == "vxworks"
415 LinkOutputKind::StaticNoPicExe
416 | LinkOutputKind::StaticPicExe
417 | LinkOutputKind::StaticDylib
420 self.cmd.arg("--static-crt");
424 fn link_dylib(&mut self, lib: &str, verbatim: bool, as_needed: bool) {
425 if self.sess.target.os == "illumos" && lib == "c" {
426 // libc will be added via late_link_args on illumos so that it will
427 // appear last in the library search order.
428 // FIXME: This should be replaced by a more complete and generic
429 // mechanism for controlling the order of library arguments passed
434 if self.sess.target.is_like_osx {
435 // FIXME(81490): ld64 doesn't support these flags but macOS 11
436 // has -needed-l{} / -needed_library {}
437 // but we have no way to detect that here.
438 self.sess.warn("`as-needed` modifier not implemented yet for ld64");
439 } else if self.is_gnu && !self.sess.target.is_like_windows {
440 self.linker_arg("--no-as-needed");
442 self.sess.warn("`as-needed` modifier not supported for current linker");
446 self.cmd.arg(format!("-l{}{lib}", if verbatim && self.is_gnu { ":" } else { "" },));
448 if self.sess.target.is_like_osx {
449 // See above FIXME comment
450 } else if self.is_gnu && !self.sess.target.is_like_windows {
451 self.linker_arg("--as-needed");
455 fn link_staticlib(&mut self, lib: &str, verbatim: bool) {
457 self.cmd.arg(format!("-l{}{lib}", if verbatim && self.is_gnu { ":" } else { "" },));
459 fn link_rlib(&mut self, lib: &Path) {
463 fn include_path(&mut self, path: &Path) {
464 self.cmd.arg("-L").arg(path);
466 fn framework_path(&mut self, path: &Path) {
467 self.cmd.arg("-F").arg(path);
469 fn output_filename(&mut self, path: &Path) {
470 self.cmd.arg("-o").arg(path);
472 fn add_object(&mut self, path: &Path) {
475 fn full_relro(&mut self) {
476 self.linker_args(&["-zrelro", "-znow"]);
478 fn partial_relro(&mut self) {
479 self.linker_arg("-zrelro");
481 fn no_relro(&mut self) {
482 self.linker_arg("-znorelro");
485 fn link_rust_dylib(&mut self, lib: &str, _path: &Path) {
487 self.cmd.arg(format!("-l{}", lib));
490 fn link_framework(&mut self, framework: &str, as_needed: bool) {
493 // FIXME(81490): ld64 as of macOS 11 supports the -needed_framework
494 // flag but we have no way to detect that here.
495 // self.cmd.arg("-needed_framework").arg(framework);
496 self.sess.warn("`as-needed` modifier not implemented yet for ld64");
498 self.cmd.arg("-framework").arg(framework);
501 // Here we explicitly ask that the entire archive is included into the
502 // result artifact. For more details see #15460, but the gist is that
503 // the linker will strip away any unused objects in the archive if we
504 // don't otherwise explicitly reference them. This can occur for
505 // libraries which are just providing bindings, libraries with generic
507 fn link_whole_staticlib(&mut self, lib: &str, verbatim: bool, search_path: &[PathBuf]) {
509 let target = &self.sess.target;
510 if !target.is_like_osx {
511 self.linker_arg("--whole-archive");
512 self.cmd.arg(format!("-l{}{lib}", if verbatim && self.is_gnu { ":" } else { "" },));
513 self.linker_arg("--no-whole-archive");
515 // -force_load is the macOS equivalent of --whole-archive, but it
516 // involves passing the full path to the library to link.
517 self.linker_arg("-force_load");
518 let lib = find_native_static_library(lib, Some(verbatim), search_path, &self.sess);
519 self.linker_arg(&lib);
523 fn link_whole_rlib(&mut self, lib: &Path) {
525 if self.sess.target.is_like_osx {
526 self.linker_arg("-force_load");
527 self.linker_arg(&lib);
529 self.linker_arg("--whole-archive").cmd.arg(lib);
530 self.linker_arg("--no-whole-archive");
534 fn gc_sections(&mut self, keep_metadata: bool) {
535 // The dead_strip option to the linker specifies that functions and data
536 // unreachable by the entry point will be removed. This is quite useful
537 // with Rust's compilation model of compiling libraries at a time into
538 // one object file. For example, this brings hello world from 1.7MB to
541 // Note that this is done for both executables and dynamic libraries. We
542 // won't get much benefit from dylibs because LLVM will have already
543 // stripped away as much as it could. This has not been seen to impact
544 // link times negatively.
546 // -dead_strip can't be part of the pre_link_args because it's also used
547 // for partial linking when using multiple codegen units (-r). So we
549 if self.sess.target.is_like_osx {
550 self.linker_arg("-dead_strip");
552 // If we're building a dylib, we don't use --gc-sections because LLVM
553 // has already done the best it can do, and we also don't want to
554 // eliminate the metadata. If we're building an executable, however,
555 // --gc-sections drops the size of hello world from 1.8MB to 597K, a 67%
557 } else if (self.is_gnu || self.sess.target.is_like_wasm) && !keep_metadata {
558 self.linker_arg("--gc-sections");
562 fn no_gc_sections(&mut self) {
563 if self.is_gnu || self.sess.target.is_like_wasm {
564 self.linker_arg("--no-gc-sections");
568 fn optimize(&mut self) {
569 if !self.is_gnu && !self.sess.target.is_like_wasm {
573 // GNU-style linkers support optimization with -O. GNU ld doesn't
574 // need a numeric argument, but other linkers do.
575 if self.sess.opts.optimize == config::OptLevel::Default
576 || self.sess.opts.optimize == config::OptLevel::Aggressive
578 self.linker_arg("-O1");
582 fn pgo_gen(&mut self) {
587 // If we're doing PGO generation stuff and on a GNU-like linker, use the
588 // "-u" flag to properly pull in the profiler runtime bits.
590 // This is because LLVM otherwise won't add the needed initialization
591 // for us on Linux (though the extra flag should be harmless if it
594 // See https://reviews.llvm.org/D14033 and https://reviews.llvm.org/D14030.
596 // Though it may be worth to try to revert those changes upstream, since
597 // the overhead of the initialization should be minor.
599 self.cmd.arg("__llvm_profile_runtime");
602 fn control_flow_guard(&mut self) {}
604 fn debuginfo(&mut self, strip: Strip, _: &[PathBuf]) {
605 // MacOS linker doesn't support stripping symbols directly anymore.
606 if self.sess.target.is_like_osx {
612 Strip::Debuginfo => {
613 self.linker_arg("--strip-debug");
616 self.linker_arg("--strip-all");
621 fn no_crt_objects(&mut self) {
623 self.cmd.arg("-nostartfiles");
627 fn no_default_libraries(&mut self) {
629 self.cmd.arg("-nodefaultlibs");
633 fn export_symbols(&mut self, tmpdir: &Path, crate_type: CrateType, symbols: &[String]) {
634 // Symbol visibility in object files typically takes care of this.
635 if crate_type == CrateType::Executable {
636 let should_export_executable_symbols =
637 self.sess.opts.unstable_opts.export_executable_symbols;
638 if self.sess.target.override_export_symbols.is_none()
639 && !should_export_executable_symbols
645 // We manually create a list of exported symbols to ensure we don't expose any more.
646 // The object files have far more public symbols than we actually want to export,
647 // so we hide them all here.
649 if !self.sess.target.limit_rdylib_exports {
653 // FIXME(#99978) hide #[no_mangle] symbols for proc-macros
655 let is_windows = self.sess.target.is_like_windows;
656 let path = tmpdir.join(if is_windows { "list.def" } else { "list" });
658 debug!("EXPORTED SYMBOLS:");
660 if self.sess.target.is_like_osx {
661 // Write a plain, newline-separated list of symbols
662 let res: io::Result<()> = try {
663 let mut f = BufWriter::new(File::create(&path)?);
666 writeln!(f, "_{}", sym)?;
669 if let Err(e) = res {
670 self.sess.emit_fatal(LibDefWriteFailure { error_description: format!("{e}") });
672 } else if is_windows {
673 let res: io::Result<()> = try {
674 let mut f = BufWriter::new(File::create(&path)?);
676 // .def file similar to MSVC one but without LIBRARY section
677 // because LD doesn't like when it's empty
678 writeln!(f, "EXPORTS")?;
679 for symbol in symbols {
680 debug!(" _{}", symbol);
681 writeln!(f, " {}", symbol)?;
684 if let Err(e) = res {
685 self.sess.emit_fatal(LibDefWriteFailure { error_description: format!("{e}") });
688 // Write an LD version script
689 let res: io::Result<()> = try {
690 let mut f = BufWriter::new(File::create(&path)?);
692 if !symbols.is_empty() {
693 writeln!(f, " global:")?;
696 writeln!(f, " {};", sym)?;
699 writeln!(f, "\n local:\n *;\n}};")?;
701 if let Err(e) = res {
702 self.sess.fatal(&format!("failed to write version script: {}", e));
706 if self.sess.target.is_like_osx {
707 self.linker_args(&[OsString::from("-exported_symbols_list"), path.into()]);
708 } else if self.sess.target.is_like_solaris {
709 self.linker_args(&[OsString::from("-M"), path.into()]);
712 self.linker_arg(path);
714 let mut arg = OsString::from("--version-script=");
716 self.linker_arg(arg);
721 fn subsystem(&mut self, subsystem: &str) {
722 self.linker_arg("--subsystem");
723 self.linker_arg(&subsystem);
726 fn reset_per_library_state(&mut self) {
727 self.hint_dynamic(); // Reset to default before returning the composed command line.
730 fn linker_plugin_lto(&mut self) {
731 match self.sess.opts.cg.linker_plugin_lto {
732 LinkerPluginLto::Disabled => {
735 LinkerPluginLto::LinkerPluginAuto => {
736 self.push_linker_plugin_lto_args(None);
738 LinkerPluginLto::LinkerPlugin(ref path) => {
739 self.push_linker_plugin_lto_args(Some(path.as_os_str()));
744 // Add the `GNU_EH_FRAME` program header which is required to locate unwinding information.
745 // Some versions of `gcc` add it implicitly, some (e.g. `musl-gcc`) don't,
746 // so we just always add it.
747 fn add_eh_frame_header(&mut self) {
748 self.linker_arg("--eh-frame-hdr");
751 fn add_no_exec(&mut self) {
752 if self.sess.target.is_like_windows {
753 self.linker_arg("--nxcompat");
754 } else if self.is_gnu {
755 self.linker_arg("-znoexecstack");
759 fn add_as_needed(&mut self) {
760 if self.is_gnu && !self.sess.target.is_like_windows {
761 self.linker_arg("--as-needed");
762 } else if self.sess.target.is_like_solaris {
763 // -z ignore is the Solaris equivalent to the GNU ld --as-needed option
764 self.linker_args(&["-z", "ignore"]);
769 pub struct MsvcLinker<'a> {
774 impl<'a> Linker for MsvcLinker<'a> {
775 fn cmd(&mut self) -> &mut Command {
779 fn set_output_kind(&mut self, output_kind: LinkOutputKind, out_filename: &Path) {
781 LinkOutputKind::DynamicNoPicExe
782 | LinkOutputKind::DynamicPicExe
783 | LinkOutputKind::StaticNoPicExe
784 | LinkOutputKind::StaticPicExe => {}
785 LinkOutputKind::DynamicDylib | LinkOutputKind::StaticDylib => {
786 self.cmd.arg("/DLL");
787 let mut arg: OsString = "/IMPLIB:".into();
788 arg.push(out_filename.with_extension("dll.lib"));
791 LinkOutputKind::WasiReactorExe => {
792 panic!("can't link as reactor on non-wasi target");
797 fn link_rlib(&mut self, lib: &Path) {
800 fn add_object(&mut self, path: &Path) {
804 fn gc_sections(&mut self, _keep_metadata: bool) {
805 // MSVC's ICF (Identical COMDAT Folding) link optimization is
806 // slow for Rust and thus we disable it by default when not in
807 // optimization build.
808 if self.sess.opts.optimize != config::OptLevel::No {
809 self.cmd.arg("/OPT:REF,ICF");
811 // It is necessary to specify NOICF here, because /OPT:REF
812 // implies ICF by default.
813 self.cmd.arg("/OPT:REF,NOICF");
817 fn no_gc_sections(&mut self) {
818 self.cmd.arg("/OPT:NOREF,NOICF");
821 fn link_dylib(&mut self, lib: &str, verbatim: bool, _as_needed: bool) {
822 self.cmd.arg(format!("{}{}", lib, if verbatim { "" } else { ".lib" }));
825 fn link_rust_dylib(&mut self, lib: &str, path: &Path) {
826 // When producing a dll, the MSVC linker may not actually emit a
827 // `foo.lib` file if the dll doesn't actually export any symbols, so we
828 // check to see if the file is there and just omit linking to it if it's
830 let name = format!("{}.dll.lib", lib);
831 if path.join(&name).exists() {
836 fn link_staticlib(&mut self, lib: &str, verbatim: bool) {
837 self.cmd.arg(format!("{}{}", lib, if verbatim { "" } else { ".lib" }));
840 fn full_relro(&mut self) {
844 fn partial_relro(&mut self) {
848 fn no_relro(&mut self) {
852 fn no_crt_objects(&mut self) {
856 fn no_default_libraries(&mut self) {
857 self.cmd.arg("/NODEFAULTLIB");
860 fn include_path(&mut self, path: &Path) {
861 let mut arg = OsString::from("/LIBPATH:");
866 fn output_filename(&mut self, path: &Path) {
867 let mut arg = OsString::from("/OUT:");
872 fn framework_path(&mut self, _path: &Path) {
873 bug!("frameworks are not supported on windows")
875 fn link_framework(&mut self, _framework: &str, _as_needed: bool) {
876 bug!("frameworks are not supported on windows")
879 fn link_whole_staticlib(&mut self, lib: &str, verbatim: bool, _search_path: &[PathBuf]) {
880 self.cmd.arg(format!("/WHOLEARCHIVE:{}{}", lib, if verbatim { "" } else { ".lib" }));
882 fn link_whole_rlib(&mut self, path: &Path) {
883 let mut arg = OsString::from("/WHOLEARCHIVE:");
887 fn optimize(&mut self) {
888 // Needs more investigation of `/OPT` arguments
891 fn pgo_gen(&mut self) {
892 // Nothing needed here.
895 fn control_flow_guard(&mut self) {
896 self.cmd.arg("/guard:cf");
899 fn debuginfo(&mut self, strip: Strip, natvis_debugger_visualizers: &[PathBuf]) {
902 // This will cause the Microsoft linker to generate a PDB file
903 // from the CodeView line tables in the object files.
904 self.cmd.arg("/DEBUG");
906 // This will cause the Microsoft linker to embed .natvis info into the PDB file
907 let natvis_dir_path = self.sess.sysroot.join("lib\\rustlib\\etc");
908 if let Ok(natvis_dir) = fs::read_dir(&natvis_dir_path) {
909 for entry in natvis_dir {
912 let path = entry.path();
913 if path.extension() == Some("natvis".as_ref()) {
914 let mut arg = OsString::from("/NATVIS:");
921 .warn(&format!("error enumerating natvis directory: {}", err));
927 // This will cause the Microsoft linker to embed .natvis info for all crates into the PDB file
928 for path in natvis_debugger_visualizers {
929 let mut arg = OsString::from("/NATVIS:");
934 Strip::Debuginfo | Strip::Symbols => {
935 self.cmd.arg("/DEBUG:NONE");
940 // Currently the compiler doesn't use `dllexport` (an LLVM attribute) to
941 // export symbols from a dynamic library. When building a dynamic library,
942 // however, we're going to want some symbols exported, so this function
943 // generates a DEF file which lists all the symbols.
945 // The linker will read this `*.def` file and export all the symbols from
946 // the dynamic library. Note that this is not as simple as just exporting
947 // all the symbols in the current crate (as specified by `codegen.reachable`)
948 // but rather we also need to possibly export the symbols of upstream
949 // crates. Upstream rlibs may be linked statically to this dynamic library,
950 // in which case they may continue to transitively be used and hence need
951 // their symbols exported.
952 fn export_symbols(&mut self, tmpdir: &Path, crate_type: CrateType, symbols: &[String]) {
953 // Symbol visibility takes care of this typically
954 if crate_type == CrateType::Executable {
955 let should_export_executable_symbols =
956 self.sess.opts.unstable_opts.export_executable_symbols;
957 if !should_export_executable_symbols {
962 let path = tmpdir.join("lib.def");
963 let res: io::Result<()> = try {
964 let mut f = BufWriter::new(File::create(&path)?);
966 // Start off with the standard module name header and then go
967 // straight to exports.
968 writeln!(f, "LIBRARY")?;
969 writeln!(f, "EXPORTS")?;
970 for symbol in symbols {
971 debug!(" _{}", symbol);
972 writeln!(f, " {}", symbol)?;
975 if let Err(e) = res {
976 self.sess.emit_fatal(LibDefWriteFailure { error_description: format!("{e}") });
978 let mut arg = OsString::from("/DEF:");
983 fn subsystem(&mut self, subsystem: &str) {
984 // Note that previous passes of the compiler validated this subsystem,
985 // so we just blindly pass it to the linker.
986 self.cmd.arg(&format!("/SUBSYSTEM:{}", subsystem));
988 // Windows has two subsystems we're interested in right now, the console
989 // and windows subsystems. These both implicitly have different entry
990 // points (starting symbols). The console entry point starts with
991 // `mainCRTStartup` and the windows entry point starts with
992 // `WinMainCRTStartup`. These entry points, defined in system libraries,
993 // will then later probe for either `main` or `WinMain`, respectively to
994 // start the application.
996 // In Rust we just always generate a `main` function so we want control
997 // to always start there, so we force the entry point on the windows
998 // subsystem to be `mainCRTStartup` to get everything booted up
1001 // For more information see RFC #1665
1002 if subsystem == "windows" {
1003 self.cmd.arg("/ENTRY:mainCRTStartup");
1007 fn linker_plugin_lto(&mut self) {
1011 fn add_no_exec(&mut self) {
1012 self.cmd.arg("/NXCOMPAT");
1016 pub struct EmLinker<'a> {
1021 impl<'a> Linker for EmLinker<'a> {
1022 fn cmd(&mut self) -> &mut Command {
1026 fn set_output_kind(&mut self, _output_kind: LinkOutputKind, _out_filename: &Path) {}
1028 fn include_path(&mut self, path: &Path) {
1029 self.cmd.arg("-L").arg(path);
1032 fn link_staticlib(&mut self, lib: &str, _verbatim: bool) {
1033 self.cmd.arg("-l").arg(lib);
1036 fn output_filename(&mut self, path: &Path) {
1037 self.cmd.arg("-o").arg(path);
1040 fn add_object(&mut self, path: &Path) {
1044 fn link_dylib(&mut self, lib: &str, verbatim: bool, _as_needed: bool) {
1045 // Emscripten always links statically
1046 self.link_staticlib(lib, verbatim);
1049 fn link_whole_staticlib(&mut self, lib: &str, verbatim: bool, _search_path: &[PathBuf]) {
1051 self.link_staticlib(lib, verbatim);
1054 fn link_whole_rlib(&mut self, lib: &Path) {
1056 self.link_rlib(lib);
1059 fn link_rust_dylib(&mut self, lib: &str, _path: &Path) {
1060 self.link_dylib(lib, false, true);
1063 fn link_rlib(&mut self, lib: &Path) {
1064 self.add_object(lib);
1067 fn full_relro(&mut self) {
1071 fn partial_relro(&mut self) {
1075 fn no_relro(&mut self) {
1079 fn framework_path(&mut self, _path: &Path) {
1080 bug!("frameworks are not supported on Emscripten")
1083 fn link_framework(&mut self, _framework: &str, _as_needed: bool) {
1084 bug!("frameworks are not supported on Emscripten")
1087 fn gc_sections(&mut self, _keep_metadata: bool) {
1091 fn no_gc_sections(&mut self) {
1095 fn optimize(&mut self) {
1096 // Emscripten performs own optimizations
1097 self.cmd.arg(match self.sess.opts.optimize {
1098 OptLevel::No => "-O0",
1099 OptLevel::Less => "-O1",
1100 OptLevel::Default => "-O2",
1101 OptLevel::Aggressive => "-O3",
1102 OptLevel::Size => "-Os",
1103 OptLevel::SizeMin => "-Oz",
1107 fn pgo_gen(&mut self) {
1108 // noop, but maybe we need something like the gnu linker?
1111 fn control_flow_guard(&mut self) {}
1113 fn debuginfo(&mut self, _strip: Strip, _: &[PathBuf]) {
1114 // Preserve names or generate source maps depending on debug info
1115 self.cmd.arg(match self.sess.opts.debuginfo {
1116 DebugInfo::None => "-g0",
1117 DebugInfo::Limited => "--profiling-funcs",
1118 DebugInfo::Full => "-g",
1122 fn no_crt_objects(&mut self) {}
1124 fn no_default_libraries(&mut self) {
1125 self.cmd.arg("-nodefaultlibs");
1128 fn export_symbols(&mut self, _tmpdir: &Path, _crate_type: CrateType, symbols: &[String]) {
1129 debug!("EXPORTED SYMBOLS:");
1133 let mut arg = OsString::from("EXPORTED_FUNCTIONS=");
1134 let encoded = serde_json::to_string(
1135 &symbols.iter().map(|sym| "_".to_owned() + sym).collect::<Vec<_>>(),
1138 debug!("{}", encoded);
1145 fn subsystem(&mut self, _subsystem: &str) {
1149 fn linker_plugin_lto(&mut self) {
1154 pub struct WasmLd<'a> {
1159 impl<'a> WasmLd<'a> {
1160 fn new(mut cmd: Command, sess: &'a Session) -> WasmLd<'a> {
1161 // If the atomics feature is enabled for wasm then we need a whole bunch
1164 // * `--shared-memory` - the link won't even succeed without this, flags
1165 // the one linear memory as `shared`
1167 // * `--max-memory=1G` - when specifying a shared memory this must also
1168 // be specified. We conservatively choose 1GB but users should be able
1169 // to override this with `-C link-arg`.
1171 // * `--import-memory` - it doesn't make much sense for memory to be
1172 // exported in a threaded module because typically you're
1173 // sharing memory and instantiating the module multiple times. As a
1174 // result if it were exported then we'd just have no sharing.
1176 // On wasm32-unknown-unknown, we also export symbols for glue code to use:
1177 // * `--export=*tls*` - when `#[thread_local]` symbols are used these
1178 // symbols are how the TLS segments are initialized and configured.
1179 if sess.target_features.contains(&sym::atomics) {
1180 cmd.arg("--shared-memory");
1181 cmd.arg("--max-memory=1073741824");
1182 cmd.arg("--import-memory");
1183 if sess.target.os == "unknown" {
1184 cmd.arg("--export=__wasm_init_tls");
1185 cmd.arg("--export=__tls_size");
1186 cmd.arg("--export=__tls_align");
1187 cmd.arg("--export=__tls_base");
1190 WasmLd { cmd, sess }
1194 impl<'a> Linker for WasmLd<'a> {
1195 fn cmd(&mut self) -> &mut Command {
1199 fn set_output_kind(&mut self, output_kind: LinkOutputKind, _out_filename: &Path) {
1201 LinkOutputKind::DynamicNoPicExe
1202 | LinkOutputKind::DynamicPicExe
1203 | LinkOutputKind::StaticNoPicExe
1204 | LinkOutputKind::StaticPicExe => {}
1205 LinkOutputKind::DynamicDylib | LinkOutputKind::StaticDylib => {
1206 self.cmd.arg("--no-entry");
1208 LinkOutputKind::WasiReactorExe => {
1209 self.cmd.arg("--entry");
1210 self.cmd.arg("_initialize");
1215 fn link_dylib(&mut self, lib: &str, _verbatim: bool, _as_needed: bool) {
1216 self.cmd.arg("-l").arg(lib);
1219 fn link_staticlib(&mut self, lib: &str, _verbatim: bool) {
1220 self.cmd.arg("-l").arg(lib);
1223 fn link_rlib(&mut self, lib: &Path) {
1227 fn include_path(&mut self, path: &Path) {
1228 self.cmd.arg("-L").arg(path);
1231 fn framework_path(&mut self, _path: &Path) {
1232 panic!("frameworks not supported")
1235 fn output_filename(&mut self, path: &Path) {
1236 self.cmd.arg("-o").arg(path);
1239 fn add_object(&mut self, path: &Path) {
1243 fn full_relro(&mut self) {}
1245 fn partial_relro(&mut self) {}
1247 fn no_relro(&mut self) {}
1249 fn link_rust_dylib(&mut self, lib: &str, _path: &Path) {
1250 self.cmd.arg("-l").arg(lib);
1253 fn link_framework(&mut self, _framework: &str, _as_needed: bool) {
1254 panic!("frameworks not supported")
1257 fn link_whole_staticlib(&mut self, lib: &str, _verbatim: bool, _search_path: &[PathBuf]) {
1258 self.cmd.arg("-l").arg(lib);
1261 fn link_whole_rlib(&mut self, lib: &Path) {
1265 fn gc_sections(&mut self, _keep_metadata: bool) {
1266 self.cmd.arg("--gc-sections");
1269 fn no_gc_sections(&mut self) {
1270 self.cmd.arg("--no-gc-sections");
1273 fn optimize(&mut self) {
1274 self.cmd.arg(match self.sess.opts.optimize {
1275 OptLevel::No => "-O0",
1276 OptLevel::Less => "-O1",
1277 OptLevel::Default => "-O2",
1278 OptLevel::Aggressive => "-O3",
1279 // Currently LLD doesn't support `Os` and `Oz`, so pass through `O2`
1281 OptLevel::Size => "-O2",
1282 OptLevel::SizeMin => "-O2",
1286 fn pgo_gen(&mut self) {}
1288 fn debuginfo(&mut self, strip: Strip, _: &[PathBuf]) {
1291 Strip::Debuginfo => {
1292 self.cmd.arg("--strip-debug");
1295 self.cmd.arg("--strip-all");
1300 fn control_flow_guard(&mut self) {}
1302 fn no_crt_objects(&mut self) {}
1304 fn no_default_libraries(&mut self) {}
1306 fn export_symbols(&mut self, _tmpdir: &Path, _crate_type: CrateType, symbols: &[String]) {
1307 for sym in symbols {
1308 self.cmd.arg("--export").arg(&sym);
1311 // LLD will hide these otherwise-internal symbols since it only exports
1312 // symbols explicitly passed via the `--export` flags above and hides all
1313 // others. Various bits and pieces of wasm32-unknown-unknown tooling use
1314 // this, so be sure these symbols make their way out of the linker as well.
1315 if self.sess.target.os == "unknown" {
1316 self.cmd.arg("--export=__heap_base");
1317 self.cmd.arg("--export=__data_end");
1321 fn subsystem(&mut self, _subsystem: &str) {}
1323 fn linker_plugin_lto(&mut self) {
1324 // Do nothing for now
1328 /// Linker shepherd script for L4Re (Fiasco)
1329 pub struct L4Bender<'a> {
1332 hinted_static: bool,
1335 impl<'a> Linker for L4Bender<'a> {
1336 fn link_dylib(&mut self, _lib: &str, _verbatim: bool, _as_needed: bool) {
1337 bug!("dylibs are not supported on L4Re");
1339 fn link_staticlib(&mut self, lib: &str, _verbatim: bool) {
1341 self.cmd.arg(format!("-PC{}", lib));
1343 fn link_rlib(&mut self, lib: &Path) {
1347 fn include_path(&mut self, path: &Path) {
1348 self.cmd.arg("-L").arg(path);
1350 fn framework_path(&mut self, _: &Path) {
1351 bug!("frameworks are not supported on L4Re");
1353 fn output_filename(&mut self, path: &Path) {
1354 self.cmd.arg("-o").arg(path);
1357 fn add_object(&mut self, path: &Path) {
1361 fn full_relro(&mut self) {
1362 self.cmd.arg("-zrelro");
1363 self.cmd.arg("-znow");
1366 fn partial_relro(&mut self) {
1367 self.cmd.arg("-zrelro");
1370 fn no_relro(&mut self) {
1371 self.cmd.arg("-znorelro");
1374 fn cmd(&mut self) -> &mut Command {
1378 fn set_output_kind(&mut self, _output_kind: LinkOutputKind, _out_filename: &Path) {}
1380 fn link_rust_dylib(&mut self, _: &str, _: &Path) {
1381 panic!("Rust dylibs not supported");
1384 fn link_framework(&mut self, _framework: &str, _as_needed: bool) {
1385 bug!("frameworks not supported on L4Re");
1388 fn link_whole_staticlib(&mut self, lib: &str, _verbatim: bool, _search_path: &[PathBuf]) {
1390 self.cmd.arg("--whole-archive").arg(format!("-l{}", lib));
1391 self.cmd.arg("--no-whole-archive");
1394 fn link_whole_rlib(&mut self, lib: &Path) {
1396 self.cmd.arg("--whole-archive").arg(lib).arg("--no-whole-archive");
1399 fn gc_sections(&mut self, keep_metadata: bool) {
1401 self.cmd.arg("--gc-sections");
1405 fn no_gc_sections(&mut self) {
1406 self.cmd.arg("--no-gc-sections");
1409 fn optimize(&mut self) {
1410 // GNU-style linkers support optimization with -O. GNU ld doesn't
1411 // need a numeric argument, but other linkers do.
1412 if self.sess.opts.optimize == config::OptLevel::Default
1413 || self.sess.opts.optimize == config::OptLevel::Aggressive
1415 self.cmd.arg("-O1");
1419 fn pgo_gen(&mut self) {}
1421 fn debuginfo(&mut self, strip: Strip, _: &[PathBuf]) {
1424 Strip::Debuginfo => {
1425 self.cmd().arg("--strip-debug");
1428 self.cmd().arg("--strip-all");
1433 fn no_default_libraries(&mut self) {
1434 self.cmd.arg("-nostdlib");
1437 fn export_symbols(&mut self, _: &Path, _: CrateType, _: &[String]) {
1438 // ToDo, not implemented, copy from GCC
1439 self.sess.warn("exporting symbols not implemented yet for L4Bender");
1443 fn subsystem(&mut self, subsystem: &str) {
1444 self.cmd.arg(&format!("--subsystem {}", subsystem));
1447 fn reset_per_library_state(&mut self) {
1448 self.hint_static(); // Reset to default before returning the composed command line.
1451 fn linker_plugin_lto(&mut self) {}
1453 fn control_flow_guard(&mut self) {}
1455 fn no_crt_objects(&mut self) {}
1458 impl<'a> L4Bender<'a> {
1459 pub fn new(cmd: Command, sess: &'a Session) -> L4Bender<'a> {
1460 L4Bender { cmd: cmd, sess: sess, hinted_static: false }
1463 fn hint_static(&mut self) {
1464 if !self.hinted_static {
1465 self.cmd.arg("-static");
1466 self.hinted_static = true;
1471 fn for_each_exported_symbols_include_dep<'tcx>(
1473 crate_type: CrateType,
1474 mut callback: impl FnMut(ExportedSymbol<'tcx>, SymbolExportInfo, CrateNum),
1476 for &(symbol, info) in tcx.exported_symbols(LOCAL_CRATE).iter() {
1477 callback(symbol, info, LOCAL_CRATE);
1480 let formats = tcx.dependency_formats(());
1481 let deps = formats.iter().find_map(|(t, list)| (*t == crate_type).then_some(list)).unwrap();
1483 for (index, dep_format) in deps.iter().enumerate() {
1484 let cnum = CrateNum::new(index + 1);
1485 // For each dependency that we are linking to statically ...
1486 if *dep_format == Linkage::Static {
1487 for &(symbol, info) in tcx.exported_symbols(cnum).iter() {
1488 callback(symbol, info, cnum);
1494 pub(crate) fn exported_symbols(tcx: TyCtxt<'_>, crate_type: CrateType) -> Vec<String> {
1495 if let Some(ref exports) = tcx.sess.target.override_export_symbols {
1496 return exports.iter().map(ToString::to_string).collect();
1499 let mut symbols = Vec::new();
1501 let export_threshold = symbol_export::crates_export_threshold(&[crate_type]);
1502 for_each_exported_symbols_include_dep(tcx, crate_type, |symbol, info, cnum| {
1503 if info.level.is_below_threshold(export_threshold) {
1504 symbols.push(symbol_export::symbol_name_for_instance_in_crate(tcx, symbol, cnum));
1511 pub(crate) fn linked_symbols(
1513 crate_type: CrateType,
1514 ) -> Vec<(String, SymbolExportKind)> {
1516 CrateType::Executable | CrateType::Cdylib | CrateType::Dylib => (),
1517 CrateType::Staticlib | CrateType::ProcMacro | CrateType::Rlib => {
1522 let mut symbols = Vec::new();
1524 let export_threshold = symbol_export::crates_export_threshold(&[crate_type]);
1525 for_each_exported_symbols_include_dep(tcx, crate_type, |symbol, info, cnum| {
1526 if info.level.is_below_threshold(export_threshold) || info.used {
1528 symbol_export::linking_symbol_name_for_instance_in_crate(tcx, symbol, cnum),
1537 /// Much simplified and explicit CLI for the NVPTX linker. The linker operates
1538 /// with bitcode and uses LLVM backend to generate a PTX assembly.
1539 pub struct PtxLinker<'a> {
1544 impl<'a> Linker for PtxLinker<'a> {
1545 fn cmd(&mut self) -> &mut Command {
1549 fn set_output_kind(&mut self, _output_kind: LinkOutputKind, _out_filename: &Path) {}
1551 fn link_rlib(&mut self, path: &Path) {
1552 self.cmd.arg("--rlib").arg(path);
1555 fn link_whole_rlib(&mut self, path: &Path) {
1556 self.cmd.arg("--rlib").arg(path);
1559 fn include_path(&mut self, path: &Path) {
1560 self.cmd.arg("-L").arg(path);
1563 fn debuginfo(&mut self, _strip: Strip, _: &[PathBuf]) {
1564 self.cmd.arg("--debug");
1567 fn add_object(&mut self, path: &Path) {
1568 self.cmd.arg("--bitcode").arg(path);
1571 fn optimize(&mut self) {
1572 match self.sess.lto() {
1573 Lto::Thin | Lto::Fat | Lto::ThinLocal => {
1574 self.cmd.arg("-Olto");
1581 fn output_filename(&mut self, path: &Path) {
1582 self.cmd.arg("-o").arg(path);
1585 fn link_dylib(&mut self, _lib: &str, _verbatim: bool, _as_needed: bool) {
1586 panic!("external dylibs not supported")
1589 fn link_rust_dylib(&mut self, _lib: &str, _path: &Path) {
1590 panic!("external dylibs not supported")
1593 fn link_staticlib(&mut self, _lib: &str, _verbatim: bool) {
1594 panic!("staticlibs not supported")
1597 fn link_whole_staticlib(&mut self, _lib: &str, _verbatim: bool, _search_path: &[PathBuf]) {
1598 panic!("staticlibs not supported")
1601 fn framework_path(&mut self, _path: &Path) {
1602 panic!("frameworks not supported")
1605 fn link_framework(&mut self, _framework: &str, _as_needed: bool) {
1606 panic!("frameworks not supported")
1609 fn full_relro(&mut self) {}
1611 fn partial_relro(&mut self) {}
1613 fn no_relro(&mut self) {}
1615 fn gc_sections(&mut self, _keep_metadata: bool) {}
1617 fn no_gc_sections(&mut self) {}
1619 fn pgo_gen(&mut self) {}
1621 fn no_crt_objects(&mut self) {}
1623 fn no_default_libraries(&mut self) {}
1625 fn control_flow_guard(&mut self) {}
1627 fn export_symbols(&mut self, _tmpdir: &Path, _crate_type: CrateType, _symbols: &[String]) {}
1629 fn subsystem(&mut self, _subsystem: &str) {}
1631 fn linker_plugin_lto(&mut self) {}
1634 pub struct BpfLinker<'a> {
1639 impl<'a> Linker for BpfLinker<'a> {
1640 fn cmd(&mut self) -> &mut Command {
1644 fn set_output_kind(&mut self, _output_kind: LinkOutputKind, _out_filename: &Path) {}
1646 fn link_rlib(&mut self, path: &Path) {
1650 fn link_whole_rlib(&mut self, path: &Path) {
1654 fn include_path(&mut self, path: &Path) {
1655 self.cmd.arg("-L").arg(path);
1658 fn debuginfo(&mut self, _strip: Strip, _: &[PathBuf]) {
1659 self.cmd.arg("--debug");
1662 fn add_object(&mut self, path: &Path) {
1666 fn optimize(&mut self) {
1667 self.cmd.arg(match self.sess.opts.optimize {
1668 OptLevel::No => "-O0",
1669 OptLevel::Less => "-O1",
1670 OptLevel::Default => "-O2",
1671 OptLevel::Aggressive => "-O3",
1672 OptLevel::Size => "-Os",
1673 OptLevel::SizeMin => "-Oz",
1677 fn output_filename(&mut self, path: &Path) {
1678 self.cmd.arg("-o").arg(path);
1681 fn link_dylib(&mut self, _lib: &str, _verbatim: bool, _as_needed: bool) {
1682 panic!("external dylibs not supported")
1685 fn link_rust_dylib(&mut self, _lib: &str, _path: &Path) {
1686 panic!("external dylibs not supported")
1689 fn link_staticlib(&mut self, _lib: &str, _verbatim: bool) {
1690 panic!("staticlibs not supported")
1693 fn link_whole_staticlib(&mut self, _lib: &str, _verbatim: bool, _search_path: &[PathBuf]) {
1694 panic!("staticlibs not supported")
1697 fn framework_path(&mut self, _path: &Path) {
1698 panic!("frameworks not supported")
1701 fn link_framework(&mut self, _framework: &str, _as_needed: bool) {
1702 panic!("frameworks not supported")
1705 fn full_relro(&mut self) {}
1707 fn partial_relro(&mut self) {}
1709 fn no_relro(&mut self) {}
1711 fn gc_sections(&mut self, _keep_metadata: bool) {}
1713 fn no_gc_sections(&mut self) {}
1715 fn pgo_gen(&mut self) {}
1717 fn no_crt_objects(&mut self) {}
1719 fn no_default_libraries(&mut self) {}
1721 fn control_flow_guard(&mut self) {}
1723 fn export_symbols(&mut self, tmpdir: &Path, _crate_type: CrateType, symbols: &[String]) {
1724 let path = tmpdir.join("symbols");
1725 let res: io::Result<()> = try {
1726 let mut f = BufWriter::new(File::create(&path)?);
1727 for sym in symbols {
1728 writeln!(f, "{}", sym)?;
1731 if let Err(e) = res {
1732 self.sess.fatal(&format!("failed to write symbols file: {}", e));
1734 self.cmd.arg("--export-symbols").arg(&path);
1738 fn subsystem(&mut self, _subsystem: &str) {}
1740 fn linker_plugin_lto(&mut self) {}