| use super::archive; |
| use super::command::Command; |
| use super::symbol_export; |
| use rustc_span::symbol::sym; |
| |
| use std::ffi::{OsStr, OsString}; |
| use std::fs::{self, File}; |
| use std::io::prelude::*; |
| use std::io::{self, BufWriter}; |
| use std::mem; |
| use std::path::{Path, PathBuf}; |
| |
| use rustc_data_structures::fx::FxHashMap; |
| use rustc_hir::def_id::{CrateNum, LOCAL_CRATE}; |
| use rustc_middle::middle::dependency_format::Linkage; |
| use rustc_middle::ty::TyCtxt; |
| use rustc_serialize::{json, Encoder}; |
| use rustc_session::config::{self, CrateType, DebugInfo, LinkerPluginLto, Lto, OptLevel, Strip}; |
| use rustc_session::Session; |
| use rustc_span::symbol::Symbol; |
| use rustc_target::spec::{LinkOutputKind, LinkerFlavor, LldFlavor}; |
| |
| /// Disables non-English messages from localized linkers. |
| /// Such messages may cause issues with text encoding on Windows (#35785) |
| /// and prevent inspection of linker output in case of errors, which we occasionally do. |
| /// This should be acceptable because other messages from rustc are in English anyway, |
| /// and may also be desirable to improve searchability of the linker diagnostics. |
| pub fn disable_localization(linker: &mut Command) { |
| // No harm in setting both env vars simultaneously. |
| // Unix-style linkers. |
| linker.env("LC_ALL", "C"); |
| // MSVC's `link.exe`. |
| linker.env("VSLANG", "1033"); |
| } |
| |
| /// For all the linkers we support, and information they might |
| /// need out of the shared crate context before we get rid of it. |
| #[derive(RustcEncodable, RustcDecodable)] |
| pub struct LinkerInfo { |
| exports: FxHashMap<CrateType, Vec<String>>, |
| } |
| |
| impl LinkerInfo { |
| pub fn new(tcx: TyCtxt<'_>) -> LinkerInfo { |
| LinkerInfo { |
| exports: tcx |
| .sess |
| .crate_types() |
| .iter() |
| .map(|&c| (c, exported_symbols(tcx, c))) |
| .collect(), |
| } |
| } |
| |
| pub fn to_linker<'a>( |
| &'a self, |
| cmd: Command, |
| sess: &'a Session, |
| flavor: LinkerFlavor, |
| target_cpu: &'a str, |
| ) -> Box<dyn Linker + 'a> { |
| match flavor { |
| LinkerFlavor::Lld(LldFlavor::Link) | LinkerFlavor::Msvc => { |
| Box::new(MsvcLinker { cmd, sess, info: self }) as Box<dyn Linker> |
| } |
| LinkerFlavor::Em => Box::new(EmLinker { cmd, sess, info: self }) as Box<dyn Linker>, |
| LinkerFlavor::Gcc => Box::new(GccLinker { |
| cmd, |
| sess, |
| info: self, |
| hinted_static: false, |
| is_ld: false, |
| target_cpu, |
| }) as Box<dyn Linker>, |
| |
| LinkerFlavor::Lld(LldFlavor::Ld) |
| | LinkerFlavor::Lld(LldFlavor::Ld64) |
| | LinkerFlavor::Ld => Box::new(GccLinker { |
| cmd, |
| sess, |
| info: self, |
| hinted_static: false, |
| is_ld: true, |
| target_cpu, |
| }) as Box<dyn Linker>, |
| |
| LinkerFlavor::Lld(LldFlavor::Wasm) => { |
| Box::new(WasmLd::new(cmd, sess, self)) as Box<dyn Linker> |
| } |
| |
| LinkerFlavor::PtxLinker => Box::new(PtxLinker { cmd, sess }) as Box<dyn Linker>, |
| } |
| } |
| } |
| |
| /// Linker abstraction used by `back::link` to build up the command to invoke a |
| /// linker. |
| /// |
| /// This trait is the total list of requirements needed by `back::link` and |
| /// represents the meaning of each option being passed down. This trait is then |
| /// used to dispatch on whether a GNU-like linker (generally `ld.exe`) or an |
| /// MSVC linker (e.g., `link.exe`) is being used. |
| pub trait Linker { |
| fn cmd(&mut self) -> &mut Command; |
| fn set_output_kind(&mut self, output_kind: LinkOutputKind, out_filename: &Path); |
| fn link_dylib(&mut self, lib: Symbol); |
| fn link_rust_dylib(&mut self, lib: Symbol, path: &Path); |
| fn link_framework(&mut self, framework: Symbol); |
| fn link_staticlib(&mut self, lib: Symbol); |
| fn link_rlib(&mut self, lib: &Path); |
| fn link_whole_rlib(&mut self, lib: &Path); |
| fn link_whole_staticlib(&mut self, lib: Symbol, search_path: &[PathBuf]); |
| fn include_path(&mut self, path: &Path); |
| fn framework_path(&mut self, path: &Path); |
| fn output_filename(&mut self, path: &Path); |
| fn add_object(&mut self, path: &Path); |
| fn gc_sections(&mut self, keep_metadata: bool); |
| fn full_relro(&mut self); |
| fn partial_relro(&mut self); |
| fn no_relro(&mut self); |
| fn optimize(&mut self); |
| fn pgo_gen(&mut self); |
| fn control_flow_guard(&mut self); |
| fn debuginfo(&mut self, strip: Strip); |
| fn no_crt_objects(&mut self); |
| fn no_default_libraries(&mut self); |
| fn export_symbols(&mut self, tmpdir: &Path, crate_type: CrateType); |
| fn subsystem(&mut self, subsystem: &str); |
| fn group_start(&mut self); |
| fn group_end(&mut self); |
| fn linker_plugin_lto(&mut self); |
| fn add_eh_frame_header(&mut self) {} |
| fn finalize(&mut self); |
| } |
| |
| impl dyn Linker + '_ { |
| pub fn arg(&mut self, arg: impl AsRef<OsStr>) { |
| self.cmd().arg(arg); |
| } |
| |
| pub fn args(&mut self, args: impl IntoIterator<Item: AsRef<OsStr>>) { |
| self.cmd().args(args); |
| } |
| |
| pub fn take_cmd(&mut self) -> Command { |
| mem::replace(self.cmd(), Command::new("")) |
| } |
| } |
| |
| pub struct GccLinker<'a> { |
| cmd: Command, |
| sess: &'a Session, |
| info: &'a LinkerInfo, |
| hinted_static: bool, // Keeps track of the current hinting mode. |
| // Link as ld |
| is_ld: bool, |
| target_cpu: &'a str, |
| } |
| |
| impl<'a> GccLinker<'a> { |
| /// Argument that must be passed *directly* to the linker |
| /// |
| /// These arguments need to be prepended with `-Wl`, when a GCC-style linker is used. |
| fn linker_arg<S>(&mut self, arg: S) -> &mut Self |
| where |
| S: AsRef<OsStr>, |
| { |
| if !self.is_ld { |
| let mut os = OsString::from("-Wl,"); |
| os.push(arg.as_ref()); |
| self.cmd.arg(os); |
| } else { |
| self.cmd.arg(arg); |
| } |
| self |
| } |
| |
| fn takes_hints(&self) -> bool { |
| // Really this function only returns true if the underlying linker |
| // configured for a compiler is binutils `ld.bfd` and `ld.gold`. We |
| // don't really have a foolproof way to detect that, so rule out some |
| // platforms where currently this is guaranteed to *not* be the case: |
| // |
| // * On OSX they have their own linker, not binutils' |
| // * For WebAssembly the only functional linker is LLD, which doesn't |
| // support hint flags |
| !self.sess.target.target.options.is_like_osx && self.sess.target.target.arch != "wasm32" |
| } |
| |
| // Some platforms take hints about whether a library is static or dynamic. |
| // For those that support this, we ensure we pass the option if the library |
| // was flagged "static" (most defaults are dynamic) to ensure that if |
| // libfoo.a and libfoo.so both exist that the right one is chosen. |
| fn hint_static(&mut self) { |
| if !self.takes_hints() { |
| return; |
| } |
| if !self.hinted_static { |
| self.linker_arg("-Bstatic"); |
| self.hinted_static = true; |
| } |
| } |
| |
| fn hint_dynamic(&mut self) { |
| if !self.takes_hints() { |
| return; |
| } |
| if self.hinted_static { |
| self.linker_arg("-Bdynamic"); |
| self.hinted_static = false; |
| } |
| } |
| |
| fn push_linker_plugin_lto_args(&mut self, plugin_path: Option<&OsStr>) { |
| if let Some(plugin_path) = plugin_path { |
| let mut arg = OsString::from("-plugin="); |
| arg.push(plugin_path); |
| self.linker_arg(&arg); |
| } |
| |
| let opt_level = match self.sess.opts.optimize { |
| config::OptLevel::No => "O0", |
| config::OptLevel::Less => "O1", |
| config::OptLevel::Default => "O2", |
| config::OptLevel::Aggressive => "O3", |
| config::OptLevel::Size => "Os", |
| config::OptLevel::SizeMin => "Oz", |
| }; |
| |
| self.linker_arg(&format!("-plugin-opt={}", opt_level)); |
| let target_cpu = self.target_cpu; |
| self.linker_arg(&format!("-plugin-opt=mcpu={}", target_cpu)); |
| } |
| |
| fn build_dylib(&mut self, out_filename: &Path) { |
| // On mac we need to tell the linker to let this library be rpathed |
| if self.sess.target.target.options.is_like_osx { |
| self.cmd.arg("-dynamiclib"); |
| self.linker_arg("-dylib"); |
| |
| // Note that the `osx_rpath_install_name` option here is a hack |
| // purely to support rustbuild right now, we should get a more |
| // principled solution at some point to force the compiler to pass |
| // the right `-Wl,-install_name` with an `@rpath` in it. |
| if self.sess.opts.cg.rpath || self.sess.opts.debugging_opts.osx_rpath_install_name { |
| self.linker_arg("-install_name"); |
| let mut v = OsString::from("@rpath/"); |
| v.push(out_filename.file_name().unwrap()); |
| self.linker_arg(&v); |
| } |
| } else { |
| self.cmd.arg("-shared"); |
| if self.sess.target.target.options.is_like_windows { |
| // The output filename already contains `dll_suffix` so |
| // the resulting import library will have a name in the |
| // form of libfoo.dll.a |
| let implib_name = |
| out_filename.file_name().and_then(|file| file.to_str()).map(|file| { |
| format!( |
| "{}{}{}", |
| self.sess.target.target.options.staticlib_prefix, |
| file, |
| self.sess.target.target.options.staticlib_suffix |
| ) |
| }); |
| if let Some(implib_name) = implib_name { |
| let implib = out_filename.parent().map(|dir| dir.join(&implib_name)); |
| if let Some(implib) = implib { |
| self.linker_arg(&format!("--out-implib,{}", (*implib).to_str().unwrap())); |
| } |
| } |
| } |
| } |
| } |
| } |
| |
| impl<'a> Linker for GccLinker<'a> { |
| fn cmd(&mut self) -> &mut Command { |
| &mut self.cmd |
| } |
| |
| fn set_output_kind(&mut self, output_kind: LinkOutputKind, out_filename: &Path) { |
| match output_kind { |
| LinkOutputKind::DynamicNoPicExe => { |
| if !self.is_ld && self.sess.target.target.options.linker_is_gnu { |
| self.cmd.arg("-no-pie"); |
| } |
| } |
| LinkOutputKind::DynamicPicExe => { |
| // `-pie` works for both gcc wrapper and ld. |
| self.cmd.arg("-pie"); |
| } |
| LinkOutputKind::StaticNoPicExe => { |
| // `-static` works for both gcc wrapper and ld. |
| self.cmd.arg("-static"); |
| if !self.is_ld && self.sess.target.target.options.linker_is_gnu { |
| self.cmd.arg("-no-pie"); |
| } |
| } |
| LinkOutputKind::StaticPicExe => { |
| if !self.is_ld { |
| // Note that combination `-static -pie` doesn't work as expected |
| // for the gcc wrapper, `-static` in that case suppresses `-pie`. |
| self.cmd.arg("-static-pie"); |
| } else { |
| // `--no-dynamic-linker` and `-z text` are not strictly necessary for producing |
| // a static pie, but currently passed because gcc and clang pass them. |
| // The former suppresses the `INTERP` ELF header specifying dynamic linker, |
| // which is otherwise implicitly injected by ld (but not lld). |
| // The latter doesn't change anything, only ensures that everything is pic. |
| self.cmd.args(&["-static", "-pie", "--no-dynamic-linker", "-z", "text"]); |
| } |
| } |
| LinkOutputKind::DynamicDylib => self.build_dylib(out_filename), |
| LinkOutputKind::StaticDylib => { |
| self.cmd.arg("-static"); |
| self.build_dylib(out_filename); |
| } |
| } |
| // VxWorks compiler driver introduced `--static-crt` flag specifically for rustc, |
| // it switches linking for libc and similar system libraries to static without using |
| // any `#[link]` attributes in the `libc` crate, see #72782 for details. |
| // FIXME: Switch to using `#[link]` attributes in the `libc` crate |
| // similarly to other targets. |
| if self.sess.target.target.target_os == "vxworks" |
| && matches!( |
| output_kind, |
| LinkOutputKind::StaticNoPicExe |
| | LinkOutputKind::StaticPicExe |
| | LinkOutputKind::StaticDylib |
| ) |
| { |
| self.cmd.arg("--static-crt"); |
| } |
| } |
| |
| fn link_dylib(&mut self, lib: Symbol) { |
| self.hint_dynamic(); |
| self.cmd.arg(format!("-l{}", lib)); |
| } |
| fn link_staticlib(&mut self, lib: Symbol) { |
| self.hint_static(); |
| self.cmd.arg(format!("-l{}", lib)); |
| } |
| fn link_rlib(&mut self, lib: &Path) { |
| self.hint_static(); |
| self.cmd.arg(lib); |
| } |
| fn include_path(&mut self, path: &Path) { |
| self.cmd.arg("-L").arg(path); |
| } |
| fn framework_path(&mut self, path: &Path) { |
| self.cmd.arg("-F").arg(path); |
| } |
| fn output_filename(&mut self, path: &Path) { |
| self.cmd.arg("-o").arg(path); |
| } |
| fn add_object(&mut self, path: &Path) { |
| self.cmd.arg(path); |
| } |
| fn full_relro(&mut self) { |
| self.linker_arg("-zrelro"); |
| self.linker_arg("-znow"); |
| } |
| fn partial_relro(&mut self) { |
| self.linker_arg("-zrelro"); |
| } |
| fn no_relro(&mut self) { |
| self.linker_arg("-znorelro"); |
| } |
| |
| fn link_rust_dylib(&mut self, lib: Symbol, _path: &Path) { |
| self.hint_dynamic(); |
| self.cmd.arg(format!("-l{}", lib)); |
| } |
| |
| fn link_framework(&mut self, framework: Symbol) { |
| self.hint_dynamic(); |
| self.cmd.arg("-framework").sym_arg(framework); |
| } |
| |
| // Here we explicitly ask that the entire archive is included into the |
| // result artifact. For more details see #15460, but the gist is that |
| // the linker will strip away any unused objects in the archive if we |
| // don't otherwise explicitly reference them. This can occur for |
| // libraries which are just providing bindings, libraries with generic |
| // functions, etc. |
| fn link_whole_staticlib(&mut self, lib: Symbol, search_path: &[PathBuf]) { |
| self.hint_static(); |
| let target = &self.sess.target.target; |
| if !target.options.is_like_osx { |
| self.linker_arg("--whole-archive").cmd.arg(format!("-l{}", lib)); |
| self.linker_arg("--no-whole-archive"); |
| } else { |
| // -force_load is the macOS equivalent of --whole-archive, but it |
| // involves passing the full path to the library to link. |
| self.linker_arg("-force_load"); |
| let lib = archive::find_library(lib, search_path, &self.sess); |
| self.linker_arg(&lib); |
| } |
| } |
| |
| fn link_whole_rlib(&mut self, lib: &Path) { |
| self.hint_static(); |
| if self.sess.target.target.options.is_like_osx { |
| self.linker_arg("-force_load"); |
| self.linker_arg(&lib); |
| } else { |
| self.linker_arg("--whole-archive").cmd.arg(lib); |
| self.linker_arg("--no-whole-archive"); |
| } |
| } |
| |
| fn gc_sections(&mut self, keep_metadata: bool) { |
| // The dead_strip option to the linker specifies that functions and data |
| // unreachable by the entry point will be removed. This is quite useful |
| // with Rust's compilation model of compiling libraries at a time into |
| // one object file. For example, this brings hello world from 1.7MB to |
| // 458K. |
| // |
| // Note that this is done for both executables and dynamic libraries. We |
| // won't get much benefit from dylibs because LLVM will have already |
| // stripped away as much as it could. This has not been seen to impact |
| // link times negatively. |
| // |
| // -dead_strip can't be part of the pre_link_args because it's also used |
| // for partial linking when using multiple codegen units (-r). So we |
| // insert it here. |
| if self.sess.target.target.options.is_like_osx { |
| self.linker_arg("-dead_strip"); |
| } else if self.sess.target.target.options.is_like_solaris { |
| self.linker_arg("-zignore"); |
| |
| // If we're building a dylib, we don't use --gc-sections because LLVM |
| // has already done the best it can do, and we also don't want to |
| // eliminate the metadata. If we're building an executable, however, |
| // --gc-sections drops the size of hello world from 1.8MB to 597K, a 67% |
| // reduction. |
| } else if !keep_metadata { |
| self.linker_arg("--gc-sections"); |
| } |
| } |
| |
| fn optimize(&mut self) { |
| if !self.sess.target.target.options.linker_is_gnu { |
| return; |
| } |
| |
| // GNU-style linkers support optimization with -O. GNU ld doesn't |
| // need a numeric argument, but other linkers do. |
| if self.sess.opts.optimize == config::OptLevel::Default |
| || self.sess.opts.optimize == config::OptLevel::Aggressive |
| { |
| self.linker_arg("-O1"); |
| } |
| } |
| |
| fn pgo_gen(&mut self) { |
| if !self.sess.target.target.options.linker_is_gnu { |
| return; |
| } |
| |
| // If we're doing PGO generation stuff and on a GNU-like linker, use the |
| // "-u" flag to properly pull in the profiler runtime bits. |
| // |
| // This is because LLVM otherwise won't add the needed initialization |
| // for us on Linux (though the extra flag should be harmless if it |
| // does). |
| // |
| // See https://reviews.llvm.org/D14033 and https://reviews.llvm.org/D14030. |
| // |
| // Though it may be worth to try to revert those changes upstream, since |
| // the overhead of the initialization should be minor. |
| self.cmd.arg("-u"); |
| self.cmd.arg("__llvm_profile_runtime"); |
| } |
| |
| fn control_flow_guard(&mut self) {} |
| |
| fn debuginfo(&mut self, strip: Strip) { |
| match strip { |
| Strip::None => {} |
| Strip::Debuginfo => { |
| // MacOS linker does not support longhand argument --strip-debug |
| self.linker_arg("-S"); |
| } |
| Strip::Symbols => { |
| // MacOS linker does not support longhand argument --strip-all |
| self.linker_arg("-s"); |
| } |
| } |
| } |
| |
| fn no_crt_objects(&mut self) { |
| if !self.is_ld { |
| self.cmd.arg("-nostartfiles"); |
| } |
| } |
| |
| fn no_default_libraries(&mut self) { |
| if !self.is_ld { |
| self.cmd.arg("-nodefaultlibs"); |
| } |
| } |
| |
| fn export_symbols(&mut self, tmpdir: &Path, crate_type: CrateType) { |
| // Symbol visibility in object files typically takes care of this. |
| if crate_type == CrateType::Executable |
| && self.sess.target.target.options.override_export_symbols.is_none() |
| { |
| return; |
| } |
| |
| // We manually create a list of exported symbols to ensure we don't expose any more. |
| // The object files have far more public symbols than we actually want to export, |
| // so we hide them all here. |
| |
| if !self.sess.target.target.options.limit_rdylib_exports { |
| return; |
| } |
| |
| if crate_type == CrateType::ProcMacro { |
| return; |
| } |
| |
| let mut arg = OsString::new(); |
| let path = tmpdir.join("list"); |
| |
| debug!("EXPORTED SYMBOLS:"); |
| |
| if self.sess.target.target.options.is_like_osx { |
| // Write a plain, newline-separated list of symbols |
| let res: io::Result<()> = try { |
| let mut f = BufWriter::new(File::create(&path)?); |
| for sym in self.info.exports[&crate_type].iter() { |
| debug!(" _{}", sym); |
| writeln!(f, "_{}", sym)?; |
| } |
| }; |
| if let Err(e) = res { |
| self.sess.fatal(&format!("failed to write lib.def file: {}", e)); |
| } |
| } else { |
| // Write an LD version script |
| let res: io::Result<()> = try { |
| let mut f = BufWriter::new(File::create(&path)?); |
| writeln!(f, "{{")?; |
| if !self.info.exports[&crate_type].is_empty() { |
| writeln!(f, " global:")?; |
| for sym in self.info.exports[&crate_type].iter() { |
| debug!(" {};", sym); |
| writeln!(f, " {};", sym)?; |
| } |
| } |
| writeln!(f, "\n local:\n *;\n}};")?; |
| }; |
| if let Err(e) = res { |
| self.sess.fatal(&format!("failed to write version script: {}", e)); |
| } |
| } |
| |
| if self.sess.target.target.options.is_like_osx { |
| if !self.is_ld { |
| arg.push("-Wl,") |
| } |
| arg.push("-exported_symbols_list,"); |
| } else if self.sess.target.target.options.is_like_solaris { |
| if !self.is_ld { |
| arg.push("-Wl,") |
| } |
| arg.push("-M,"); |
| } else { |
| if !self.is_ld { |
| arg.push("-Wl,") |
| } |
| arg.push("--version-script="); |
| } |
| |
| arg.push(&path); |
| self.cmd.arg(arg); |
| } |
| |
| fn subsystem(&mut self, subsystem: &str) { |
| self.linker_arg("--subsystem"); |
| self.linker_arg(&subsystem); |
| } |
| |
| fn finalize(&mut self) { |
| self.hint_dynamic(); // Reset to default before returning the composed command line. |
| } |
| |
| fn group_start(&mut self) { |
| if self.takes_hints() { |
| self.linker_arg("--start-group"); |
| } |
| } |
| |
| fn group_end(&mut self) { |
| if self.takes_hints() { |
| self.linker_arg("--end-group"); |
| } |
| } |
| |
| fn linker_plugin_lto(&mut self) { |
| match self.sess.opts.cg.linker_plugin_lto { |
| LinkerPluginLto::Disabled => { |
| // Nothing to do |
| } |
| LinkerPluginLto::LinkerPluginAuto => { |
| self.push_linker_plugin_lto_args(None); |
| } |
| LinkerPluginLto::LinkerPlugin(ref path) => { |
| self.push_linker_plugin_lto_args(Some(path.as_os_str())); |
| } |
| } |
| } |
| |
| // Add the `GNU_EH_FRAME` program header which is required to locate unwinding information. |
| // Some versions of `gcc` add it implicitly, some (e.g. `musl-gcc`) don't, |
| // so we just always add it. |
| fn add_eh_frame_header(&mut self) { |
| // The condition here is "uses ELF" basically. |
| if !self.sess.target.target.options.is_like_osx |
| && !self.sess.target.target.options.is_like_windows |
| && self.sess.target.target.target_os != "uefi" |
| { |
| self.linker_arg("--eh-frame-hdr"); |
| } |
| } |
| } |
| |
| pub struct MsvcLinker<'a> { |
| cmd: Command, |
| sess: &'a Session, |
| info: &'a LinkerInfo, |
| } |
| |
| impl<'a> Linker for MsvcLinker<'a> { |
| fn cmd(&mut self) -> &mut Command { |
| &mut self.cmd |
| } |
| |
| fn set_output_kind(&mut self, output_kind: LinkOutputKind, out_filename: &Path) { |
| match output_kind { |
| LinkOutputKind::DynamicNoPicExe |
| | LinkOutputKind::DynamicPicExe |
| | LinkOutputKind::StaticNoPicExe |
| | LinkOutputKind::StaticPicExe => {} |
| LinkOutputKind::DynamicDylib | LinkOutputKind::StaticDylib => { |
| self.cmd.arg("/DLL"); |
| let mut arg: OsString = "/IMPLIB:".into(); |
| arg.push(out_filename.with_extension("dll.lib")); |
| self.cmd.arg(arg); |
| } |
| } |
| } |
| |
| fn link_rlib(&mut self, lib: &Path) { |
| self.cmd.arg(lib); |
| } |
| fn add_object(&mut self, path: &Path) { |
| self.cmd.arg(path); |
| } |
| |
| fn gc_sections(&mut self, _keep_metadata: bool) { |
| // MSVC's ICF (Identical COMDAT Folding) link optimization is |
| // slow for Rust and thus we disable it by default when not in |
| // optimization build. |
| if self.sess.opts.optimize != config::OptLevel::No { |
| self.cmd.arg("/OPT:REF,ICF"); |
| } else { |
| // It is necessary to specify NOICF here, because /OPT:REF |
| // implies ICF by default. |
| self.cmd.arg("/OPT:REF,NOICF"); |
| } |
| } |
| |
| fn link_dylib(&mut self, lib: Symbol) { |
| self.cmd.arg(&format!("{}.lib", lib)); |
| } |
| |
| fn link_rust_dylib(&mut self, lib: Symbol, path: &Path) { |
| // When producing a dll, the MSVC linker may not actually emit a |
| // `foo.lib` file if the dll doesn't actually export any symbols, so we |
| // check to see if the file is there and just omit linking to it if it's |
| // not present. |
| let name = format!("{}.dll.lib", lib); |
| if fs::metadata(&path.join(&name)).is_ok() { |
| self.cmd.arg(name); |
| } |
| } |
| |
| fn link_staticlib(&mut self, lib: Symbol) { |
| self.cmd.arg(&format!("{}.lib", lib)); |
| } |
| |
| fn full_relro(&mut self) { |
| // noop |
| } |
| |
| fn partial_relro(&mut self) { |
| // noop |
| } |
| |
| fn no_relro(&mut self) { |
| // noop |
| } |
| |
| fn no_crt_objects(&mut self) { |
| // noop |
| } |
| |
| fn no_default_libraries(&mut self) { |
| self.cmd.arg("/NODEFAULTLIB"); |
| } |
| |
| fn include_path(&mut self, path: &Path) { |
| let mut arg = OsString::from("/LIBPATH:"); |
| arg.push(path); |
| self.cmd.arg(&arg); |
| } |
| |
| fn output_filename(&mut self, path: &Path) { |
| let mut arg = OsString::from("/OUT:"); |
| arg.push(path); |
| self.cmd.arg(&arg); |
| } |
| |
| fn framework_path(&mut self, _path: &Path) { |
| bug!("frameworks are not supported on windows") |
| } |
| fn link_framework(&mut self, _framework: Symbol) { |
| bug!("frameworks are not supported on windows") |
| } |
| |
| fn link_whole_staticlib(&mut self, lib: Symbol, _search_path: &[PathBuf]) { |
| self.link_staticlib(lib); |
| self.cmd.arg(format!("/WHOLEARCHIVE:{}.lib", lib)); |
| } |
| fn link_whole_rlib(&mut self, path: &Path) { |
| self.link_rlib(path); |
| let mut arg = OsString::from("/WHOLEARCHIVE:"); |
| arg.push(path); |
| self.cmd.arg(arg); |
| } |
| fn optimize(&mut self) { |
| // Needs more investigation of `/OPT` arguments |
| } |
| |
| fn pgo_gen(&mut self) { |
| // Nothing needed here. |
| } |
| |
| fn control_flow_guard(&mut self) { |
| self.cmd.arg("/guard:cf"); |
| } |
| |
| fn debuginfo(&mut self, strip: Strip) { |
| match strip { |
| Strip::None => { |
| // This will cause the Microsoft linker to generate a PDB file |
| // from the CodeView line tables in the object files. |
| self.cmd.arg("/DEBUG"); |
| |
| // This will cause the Microsoft linker to embed .natvis info into the PDB file |
| let natvis_dir_path = self.sess.sysroot.join("lib\\rustlib\\etc"); |
| if let Ok(natvis_dir) = fs::read_dir(&natvis_dir_path) { |
| for entry in natvis_dir { |
| match entry { |
| Ok(entry) => { |
| let path = entry.path(); |
| if path.extension() == Some("natvis".as_ref()) { |
| let mut arg = OsString::from("/NATVIS:"); |
| arg.push(path); |
| self.cmd.arg(arg); |
| } |
| } |
| Err(err) => { |
| self.sess |
| .warn(&format!("error enumerating natvis directory: {}", err)); |
| } |
| } |
| } |
| } |
| } |
| Strip::Debuginfo | Strip::Symbols => { |
| self.cmd.arg("/DEBUG:NONE"); |
| } |
| } |
| } |
| |
| // Currently the compiler doesn't use `dllexport` (an LLVM attribute) to |
| // export symbols from a dynamic library. When building a dynamic library, |
| // however, we're going to want some symbols exported, so this function |
| // generates a DEF file which lists all the symbols. |
| // |
| // The linker will read this `*.def` file and export all the symbols from |
| // the dynamic library. Note that this is not as simple as just exporting |
| // all the symbols in the current crate (as specified by `codegen.reachable`) |
| // but rather we also need to possibly export the symbols of upstream |
| // crates. Upstream rlibs may be linked statically to this dynamic library, |
| // in which case they may continue to transitively be used and hence need |
| // their symbols exported. |
| fn export_symbols(&mut self, tmpdir: &Path, crate_type: CrateType) { |
| // Symbol visibility takes care of this typically |
| if crate_type == CrateType::Executable { |
| return; |
| } |
| |
| let path = tmpdir.join("lib.def"); |
| let res: io::Result<()> = try { |
| let mut f = BufWriter::new(File::create(&path)?); |
| |
| // Start off with the standard module name header and then go |
| // straight to exports. |
| writeln!(f, "LIBRARY")?; |
| writeln!(f, "EXPORTS")?; |
| for symbol in self.info.exports[&crate_type].iter() { |
| debug!(" _{}", symbol); |
| writeln!(f, " {}", symbol)?; |
| } |
| }; |
| if let Err(e) = res { |
| self.sess.fatal(&format!("failed to write lib.def file: {}", e)); |
| } |
| let mut arg = OsString::from("/DEF:"); |
| arg.push(path); |
| self.cmd.arg(&arg); |
| } |
| |
| fn subsystem(&mut self, subsystem: &str) { |
| // Note that previous passes of the compiler validated this subsystem, |
| // so we just blindly pass it to the linker. |
| self.cmd.arg(&format!("/SUBSYSTEM:{}", subsystem)); |
| |
| // Windows has two subsystems we're interested in right now, the console |
| // and windows subsystems. These both implicitly have different entry |
| // points (starting symbols). The console entry point starts with |
| // `mainCRTStartup` and the windows entry point starts with |
| // `WinMainCRTStartup`. These entry points, defined in system libraries, |
| // will then later probe for either `main` or `WinMain`, respectively to |
| // start the application. |
| // |
| // In Rust we just always generate a `main` function so we want control |
| // to always start there, so we force the entry point on the windows |
| // subsystem to be `mainCRTStartup` to get everything booted up |
| // correctly. |
| // |
| // For more information see RFC #1665 |
| if subsystem == "windows" { |
| self.cmd.arg("/ENTRY:mainCRTStartup"); |
| } |
| } |
| |
| fn finalize(&mut self) {} |
| |
| // MSVC doesn't need group indicators |
| fn group_start(&mut self) {} |
| fn group_end(&mut self) {} |
| |
| fn linker_plugin_lto(&mut self) { |
| // Do nothing |
| } |
| } |
| |
| pub struct EmLinker<'a> { |
| cmd: Command, |
| sess: &'a Session, |
| info: &'a LinkerInfo, |
| } |
| |
| impl<'a> Linker for EmLinker<'a> { |
| fn cmd(&mut self) -> &mut Command { |
| &mut self.cmd |
| } |
| |
| fn set_output_kind(&mut self, _output_kind: LinkOutputKind, _out_filename: &Path) {} |
| |
| fn include_path(&mut self, path: &Path) { |
| self.cmd.arg("-L").arg(path); |
| } |
| |
| fn link_staticlib(&mut self, lib: Symbol) { |
| self.cmd.arg("-l").sym_arg(lib); |
| } |
| |
| fn output_filename(&mut self, path: &Path) { |
| self.cmd.arg("-o").arg(path); |
| } |
| |
| fn add_object(&mut self, path: &Path) { |
| self.cmd.arg(path); |
| } |
| |
| fn link_dylib(&mut self, lib: Symbol) { |
| // Emscripten always links statically |
| self.link_staticlib(lib); |
| } |
| |
| fn link_whole_staticlib(&mut self, lib: Symbol, _search_path: &[PathBuf]) { |
| // not supported? |
| self.link_staticlib(lib); |
| } |
| |
| fn link_whole_rlib(&mut self, lib: &Path) { |
| // not supported? |
| self.link_rlib(lib); |
| } |
| |
| fn link_rust_dylib(&mut self, lib: Symbol, _path: &Path) { |
| self.link_dylib(lib); |
| } |
| |
| fn link_rlib(&mut self, lib: &Path) { |
| self.add_object(lib); |
| } |
| |
| fn full_relro(&mut self) { |
| // noop |
| } |
| |
| fn partial_relro(&mut self) { |
| // noop |
| } |
| |
| fn no_relro(&mut self) { |
| // noop |
| } |
| |
| fn framework_path(&mut self, _path: &Path) { |
| bug!("frameworks are not supported on Emscripten") |
| } |
| |
| fn link_framework(&mut self, _framework: Symbol) { |
| bug!("frameworks are not supported on Emscripten") |
| } |
| |
| fn gc_sections(&mut self, _keep_metadata: bool) { |
| // noop |
| } |
| |
| fn optimize(&mut self) { |
| // Emscripten performs own optimizations |
| self.cmd.arg(match self.sess.opts.optimize { |
| OptLevel::No => "-O0", |
| OptLevel::Less => "-O1", |
| OptLevel::Default => "-O2", |
| OptLevel::Aggressive => "-O3", |
| OptLevel::Size => "-Os", |
| OptLevel::SizeMin => "-Oz", |
| }); |
| // Unusable until https://github.com/rust-lang/rust/issues/38454 is resolved |
| self.cmd.args(&["--memory-init-file", "0"]); |
| } |
| |
| fn pgo_gen(&mut self) { |
| // noop, but maybe we need something like the gnu linker? |
| } |
| |
| fn control_flow_guard(&mut self) {} |
| |
| fn debuginfo(&mut self, _strip: Strip) { |
| // Preserve names or generate source maps depending on debug info |
| self.cmd.arg(match self.sess.opts.debuginfo { |
| DebugInfo::None => "-g0", |
| DebugInfo::Limited => "-g3", |
| DebugInfo::Full => "-g4", |
| }); |
| } |
| |
| fn no_crt_objects(&mut self) {} |
| |
| fn no_default_libraries(&mut self) { |
| self.cmd.args(&["-s", "DEFAULT_LIBRARY_FUNCS_TO_INCLUDE=[]"]); |
| } |
| |
| fn export_symbols(&mut self, _tmpdir: &Path, crate_type: CrateType) { |
| let symbols = &self.info.exports[&crate_type]; |
| |
| debug!("EXPORTED SYMBOLS:"); |
| |
| self.cmd.arg("-s"); |
| |
| let mut arg = OsString::from("EXPORTED_FUNCTIONS="); |
| let mut encoded = String::new(); |
| |
| { |
| let mut encoder = json::Encoder::new(&mut encoded); |
| let res = encoder.emit_seq(symbols.len(), |encoder| { |
| for (i, sym) in symbols.iter().enumerate() { |
| encoder.emit_seq_elt(i, |encoder| encoder.emit_str(&("_".to_owned() + sym)))?; |
| } |
| Ok(()) |
| }); |
| if let Err(e) = res { |
| self.sess.fatal(&format!("failed to encode exported symbols: {}", e)); |
| } |
| } |
| debug!("{}", encoded); |
| arg.push(encoded); |
| |
| self.cmd.arg(arg); |
| } |
| |
| fn subsystem(&mut self, _subsystem: &str) { |
| // noop |
| } |
| |
| fn finalize(&mut self) {} |
| |
| // Appears not necessary on Emscripten |
| fn group_start(&mut self) {} |
| fn group_end(&mut self) {} |
| |
| fn linker_plugin_lto(&mut self) { |
| // Do nothing |
| } |
| } |
| |
| pub struct WasmLd<'a> { |
| cmd: Command, |
| sess: &'a Session, |
| info: &'a LinkerInfo, |
| } |
| |
| impl<'a> WasmLd<'a> { |
| fn new(mut cmd: Command, sess: &'a Session, info: &'a LinkerInfo) -> WasmLd<'a> { |
| // If the atomics feature is enabled for wasm then we need a whole bunch |
| // of flags: |
| // |
| // * `--shared-memory` - the link won't even succeed without this, flags |
| // the one linear memory as `shared` |
| // |
| // * `--max-memory=1G` - when specifying a shared memory this must also |
| // be specified. We conservatively choose 1GB but users should be able |
| // to override this with `-C link-arg`. |
| // |
| // * `--import-memory` - it doesn't make much sense for memory to be |
| // exported in a threaded module because typically you're |
| // sharing memory and instantiating the module multiple times. As a |
| // result if it were exported then we'd just have no sharing. |
| // |
| // * `--export=__wasm_init_memory` - when using `--passive-segments` the |
| // linker will synthesize this function, and so we need to make sure |
| // that our usage of `--export` below won't accidentally cause this |
| // function to get deleted. |
| // |
| // * `--export=*tls*` - when `#[thread_local]` symbols are used these |
| // symbols are how the TLS segments are initialized and configured. |
| if sess.target_features.contains(&sym::atomics) { |
| cmd.arg("--shared-memory"); |
| cmd.arg("--max-memory=1073741824"); |
| cmd.arg("--import-memory"); |
| cmd.arg("--export=__wasm_init_memory"); |
| cmd.arg("--export=__wasm_init_tls"); |
| cmd.arg("--export=__tls_size"); |
| cmd.arg("--export=__tls_align"); |
| cmd.arg("--export=__tls_base"); |
| } |
| WasmLd { cmd, sess, info } |
| } |
| } |
| |
| impl<'a> Linker for WasmLd<'a> { |
| fn cmd(&mut self) -> &mut Command { |
| &mut self.cmd |
| } |
| |
| fn set_output_kind(&mut self, output_kind: LinkOutputKind, _out_filename: &Path) { |
| match output_kind { |
| LinkOutputKind::DynamicNoPicExe |
| | LinkOutputKind::DynamicPicExe |
| | LinkOutputKind::StaticNoPicExe |
| | LinkOutputKind::StaticPicExe => {} |
| LinkOutputKind::DynamicDylib | LinkOutputKind::StaticDylib => { |
| self.cmd.arg("--no-entry"); |
| } |
| } |
| } |
| |
| fn link_dylib(&mut self, lib: Symbol) { |
| self.cmd.arg("-l").sym_arg(lib); |
| } |
| |
| fn link_staticlib(&mut self, lib: Symbol) { |
| self.cmd.arg("-l").sym_arg(lib); |
| } |
| |
| fn link_rlib(&mut self, lib: &Path) { |
| self.cmd.arg(lib); |
| } |
| |
| fn include_path(&mut self, path: &Path) { |
| self.cmd.arg("-L").arg(path); |
| } |
| |
| fn framework_path(&mut self, _path: &Path) { |
| panic!("frameworks not supported") |
| } |
| |
| fn output_filename(&mut self, path: &Path) { |
| self.cmd.arg("-o").arg(path); |
| } |
| |
| fn add_object(&mut self, path: &Path) { |
| self.cmd.arg(path); |
| } |
| |
| fn full_relro(&mut self) {} |
| |
| fn partial_relro(&mut self) {} |
| |
| fn no_relro(&mut self) {} |
| |
| fn link_rust_dylib(&mut self, lib: Symbol, _path: &Path) { |
| self.cmd.arg("-l").sym_arg(lib); |
| } |
| |
| fn link_framework(&mut self, _framework: Symbol) { |
| panic!("frameworks not supported") |
| } |
| |
| fn link_whole_staticlib(&mut self, lib: Symbol, _search_path: &[PathBuf]) { |
| self.cmd.arg("-l").sym_arg(lib); |
| } |
| |
| fn link_whole_rlib(&mut self, lib: &Path) { |
| self.cmd.arg(lib); |
| } |
| |
| fn gc_sections(&mut self, _keep_metadata: bool) { |
| self.cmd.arg("--gc-sections"); |
| } |
| |
| fn optimize(&mut self) { |
| self.cmd.arg(match self.sess.opts.optimize { |
| OptLevel::No => "-O0", |
| OptLevel::Less => "-O1", |
| OptLevel::Default => "-O2", |
| OptLevel::Aggressive => "-O3", |
| // Currently LLD doesn't support `Os` and `Oz`, so pass through `O2` |
| // instead. |
| OptLevel::Size => "-O2", |
| OptLevel::SizeMin => "-O2", |
| }); |
| } |
| |
| fn pgo_gen(&mut self) {} |
| |
| fn debuginfo(&mut self, strip: Strip) { |
| match strip { |
| Strip::None => {} |
| Strip::Debuginfo => { |
| self.cmd.arg("--strip-debug"); |
| } |
| Strip::Symbols => { |
| self.cmd.arg("--strip-all"); |
| } |
| } |
| } |
| |
| fn control_flow_guard(&mut self) {} |
| |
| fn no_crt_objects(&mut self) {} |
| |
| fn no_default_libraries(&mut self) {} |
| |
| fn export_symbols(&mut self, _tmpdir: &Path, crate_type: CrateType) { |
| for sym in self.info.exports[&crate_type].iter() { |
| self.cmd.arg("--export").arg(&sym); |
| } |
| |
| // LLD will hide these otherwise-internal symbols since it only exports |
| // symbols explicity passed via the `--export` flags above and hides all |
| // others. Various bits and pieces of tooling use this, so be sure these |
| // symbols make their way out of the linker as well. |
| self.cmd.arg("--export=__heap_base"); |
| self.cmd.arg("--export=__data_end"); |
| } |
| |
| fn subsystem(&mut self, _subsystem: &str) {} |
| |
| fn finalize(&mut self) {} |
| |
| // Not needed for now with LLD |
| fn group_start(&mut self) {} |
| fn group_end(&mut self) {} |
| |
| fn linker_plugin_lto(&mut self) { |
| // Do nothing for now |
| } |
| } |
| |
| fn exported_symbols(tcx: TyCtxt<'_>, crate_type: CrateType) -> Vec<String> { |
| if let Some(ref exports) = tcx.sess.target.target.options.override_export_symbols { |
| return exports.clone(); |
| } |
| |
| let mut symbols = Vec::new(); |
| |
| let export_threshold = symbol_export::crates_export_threshold(&[crate_type]); |
| for &(symbol, level) in tcx.exported_symbols(LOCAL_CRATE).iter() { |
| if level.is_below_threshold(export_threshold) { |
| symbols.push(symbol_export::symbol_name_for_instance_in_crate( |
| tcx, |
| symbol, |
| LOCAL_CRATE, |
| )); |
| } |
| } |
| |
| let formats = tcx.dependency_formats(LOCAL_CRATE); |
| let deps = formats.iter().find_map(|(t, list)| (*t == crate_type).then_some(list)).unwrap(); |
| |
| for (index, dep_format) in deps.iter().enumerate() { |
| let cnum = CrateNum::new(index + 1); |
| // For each dependency that we are linking to statically ... |
| if *dep_format == Linkage::Static { |
| // ... we add its symbol list to our export list. |
| for &(symbol, level) in tcx.exported_symbols(cnum).iter() { |
| if !level.is_below_threshold(export_threshold) { |
| continue; |
| } |
| |
| symbols.push(symbol_export::symbol_name_for_instance_in_crate(tcx, symbol, cnum)); |
| } |
| } |
| } |
| |
| symbols |
| } |
| |
| /// Much simplified and explicit CLI for the NVPTX linker. The linker operates |
| /// with bitcode and uses LLVM backend to generate a PTX assembly. |
| pub struct PtxLinker<'a> { |
| cmd: Command, |
| sess: &'a Session, |
| } |
| |
| impl<'a> Linker for PtxLinker<'a> { |
| fn cmd(&mut self) -> &mut Command { |
| &mut self.cmd |
| } |
| |
| fn set_output_kind(&mut self, _output_kind: LinkOutputKind, _out_filename: &Path) {} |
| |
| fn link_rlib(&mut self, path: &Path) { |
| self.cmd.arg("--rlib").arg(path); |
| } |
| |
| fn link_whole_rlib(&mut self, path: &Path) { |
| self.cmd.arg("--rlib").arg(path); |
| } |
| |
| fn include_path(&mut self, path: &Path) { |
| self.cmd.arg("-L").arg(path); |
| } |
| |
| fn debuginfo(&mut self, _strip: Strip) { |
| self.cmd.arg("--debug"); |
| } |
| |
| fn add_object(&mut self, path: &Path) { |
| self.cmd.arg("--bitcode").arg(path); |
| } |
| |
| fn optimize(&mut self) { |
| match self.sess.lto() { |
| Lto::Thin | Lto::Fat | Lto::ThinLocal => { |
| self.cmd.arg("-Olto"); |
| } |
| |
| Lto::No => {} |
| }; |
| } |
| |
| fn output_filename(&mut self, path: &Path) { |
| self.cmd.arg("-o").arg(path); |
| } |
| |
| fn finalize(&mut self) { |
| // Provide the linker with fallback to internal `target-cpu`. |
| self.cmd.arg("--fallback-arch").arg(match self.sess.opts.cg.target_cpu { |
| Some(ref s) => s, |
| None => &self.sess.target.target.options.cpu, |
| }); |
| } |
| |
| fn link_dylib(&mut self, _lib: Symbol) { |
| panic!("external dylibs not supported") |
| } |
| |
| fn link_rust_dylib(&mut self, _lib: Symbol, _path: &Path) { |
| panic!("external dylibs not supported") |
| } |
| |
| fn link_staticlib(&mut self, _lib: Symbol) { |
| panic!("staticlibs not supported") |
| } |
| |
| fn link_whole_staticlib(&mut self, _lib: Symbol, _search_path: &[PathBuf]) { |
| panic!("staticlibs not supported") |
| } |
| |
| fn framework_path(&mut self, _path: &Path) { |
| panic!("frameworks not supported") |
| } |
| |
| fn link_framework(&mut self, _framework: Symbol) { |
| panic!("frameworks not supported") |
| } |
| |
| fn full_relro(&mut self) {} |
| |
| fn partial_relro(&mut self) {} |
| |
| fn no_relro(&mut self) {} |
| |
| fn gc_sections(&mut self, _keep_metadata: bool) {} |
| |
| fn pgo_gen(&mut self) {} |
| |
| fn no_crt_objects(&mut self) {} |
| |
| fn no_default_libraries(&mut self) {} |
| |
| fn control_flow_guard(&mut self) {} |
| |
| fn export_symbols(&mut self, _tmpdir: &Path, _crate_type: CrateType) {} |
| |
| fn subsystem(&mut self, _subsystem: &str) {} |
| |
| fn group_start(&mut self) {} |
| |
| fn group_end(&mut self) {} |
| |
| fn linker_plugin_lto(&mut self) {} |
| } |
