diff options
Diffstat (limited to 'compiler/rustc_codegen_ssa/src/back/linker.rs')
| -rw-r--r-- | compiler/rustc_codegen_ssa/src/back/linker.rs | 1788 |
1 files changed, 1788 insertions, 0 deletions
diff --git a/compiler/rustc_codegen_ssa/src/back/linker.rs b/compiler/rustc_codegen_ssa/src/back/linker.rs new file mode 100644 index 000000000..ce51b2e95 --- /dev/null +++ b/compiler/rustc_codegen_ssa/src/back/linker.rs @@ -0,0 +1,1788 @@ +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::path::{Path, PathBuf}; +use std::{env, mem, str}; + +use rustc_hir::def_id::{CrateNum, LOCAL_CRATE}; +use rustc_middle::middle::dependency_format::Linkage; +use rustc_middle::middle::exported_symbols::{ExportedSymbol, SymbolExportInfo, SymbolExportKind}; +use rustc_middle::ty::TyCtxt; +use rustc_session::config::{self, CrateType, DebugInfo, LinkerPluginLto, Lto, OptLevel, Strip}; +use rustc_session::Session; +use rustc_target::spec::{LinkOutputKind, LinkerFlavor, LldFlavor}; + +use cc::windows_registry; + +/// 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"); +} + +// The third parameter is for env vars, used on windows to set up the +// path for MSVC to find its DLLs, and gcc to find its bundled +// toolchain +pub fn get_linker<'a>( + sess: &'a Session, + linker: &Path, + flavor: LinkerFlavor, + self_contained: bool, + target_cpu: &'a str, +) -> Box<dyn Linker + 'a> { + let msvc_tool = windows_registry::find_tool(&sess.opts.target_triple.triple(), "link.exe"); + + // If our linker looks like a batch script on Windows then to execute this + // we'll need to spawn `cmd` explicitly. This is primarily done to handle + // emscripten where the linker is `emcc.bat` and needs to be spawned as + // `cmd /c emcc.bat ...`. + // + // This worked historically but is needed manually since #42436 (regression + // was tagged as #42791) and some more info can be found on #44443 for + // emscripten itself. + let mut cmd = match linker.to_str() { + Some(linker) if cfg!(windows) && linker.ends_with(".bat") => Command::bat_script(linker), + _ => match flavor { + LinkerFlavor::Lld(f) => Command::lld(linker, f), + LinkerFlavor::Msvc if sess.opts.cg.linker.is_none() && sess.target.linker.is_none() => { + Command::new(msvc_tool.as_ref().map_or(linker, |t| t.path())) + } + _ => Command::new(linker), + }, + }; + + // UWP apps have API restrictions enforced during Store submissions. + // To comply with the Windows App Certification Kit, + // MSVC needs to link with the Store versions of the runtime libraries (vcruntime, msvcrt, etc). + let t = &sess.target; + if (flavor == LinkerFlavor::Msvc || flavor == LinkerFlavor::Lld(LldFlavor::Link)) + && t.vendor == "uwp" + { + if let Some(ref tool) = msvc_tool { + let original_path = tool.path(); + if let Some(ref root_lib_path) = original_path.ancestors().nth(4) { + let arch = match t.arch.as_ref() { + "x86_64" => Some("x64"), + "x86" => Some("x86"), + "aarch64" => Some("arm64"), + "arm" => Some("arm"), + _ => None, + }; + if let Some(ref a) = arch { + // FIXME: Move this to `fn linker_with_args`. + let mut arg = OsString::from("/LIBPATH:"); + arg.push(format!("{}\\lib\\{}\\store", root_lib_path.display(), a)); + cmd.arg(&arg); + } else { + warn!("arch is not supported"); + } + } else { + warn!("MSVC root path lib location not found"); + } + } else { + warn!("link.exe not found"); + } + } + + // The compiler's sysroot often has some bundled tools, so add it to the + // PATH for the child. + let mut new_path = sess.get_tools_search_paths(self_contained); + let mut msvc_changed_path = false; + if sess.target.is_like_msvc { + if let Some(ref tool) = msvc_tool { + cmd.args(tool.args()); + for &(ref k, ref v) in tool.env() { + if k == "PATH" { + new_path.extend(env::split_paths(v)); + msvc_changed_path = true; + } else { + cmd.env(k, v); + } + } + } + } + + if !msvc_changed_path { + if let Some(path) = env::var_os("PATH") { + new_path.extend(env::split_paths(&path)); + } + } + cmd.env("PATH", env::join_paths(new_path).unwrap()); + + // FIXME: Move `/LIBPATH` addition for uwp targets from the linker construction + // to the linker args construction. + assert!(cmd.get_args().is_empty() || sess.target.vendor == "uwp"); + match flavor { + LinkerFlavor::Lld(LldFlavor::Link) | LinkerFlavor::Msvc => { + Box::new(MsvcLinker { cmd, sess }) as Box<dyn Linker> + } + LinkerFlavor::Em => Box::new(EmLinker { cmd, sess }) as Box<dyn Linker>, + LinkerFlavor::Gcc => { + Box::new(GccLinker { cmd, sess, target_cpu, hinted_static: false, is_ld: false }) + as Box<dyn Linker> + } + + LinkerFlavor::Lld(LldFlavor::Ld) + | LinkerFlavor::Lld(LldFlavor::Ld64) + | LinkerFlavor::Ld => { + Box::new(GccLinker { cmd, sess, target_cpu, hinted_static: false, is_ld: true }) + as Box<dyn Linker> + } + + LinkerFlavor::Lld(LldFlavor::Wasm) => Box::new(WasmLd::new(cmd, sess)) as Box<dyn Linker>, + + LinkerFlavor::PtxLinker => Box::new(PtxLinker { cmd, sess }) as Box<dyn Linker>, + + LinkerFlavor::BpfLinker => Box::new(BpfLinker { cmd, sess }) as Box<dyn Linker>, + + LinkerFlavor::L4Bender => Box::new(L4Bender::new(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: &str, verbatim: bool, as_needed: bool); + fn link_rust_dylib(&mut self, lib: &str, path: &Path); + fn link_framework(&mut self, framework: &str, as_needed: bool); + fn link_staticlib(&mut self, lib: &str, verbatim: bool); + fn link_rlib(&mut self, lib: &Path); + fn link_whole_rlib(&mut self, lib: &Path); + fn link_whole_staticlib(&mut self, lib: &str, verbatim: bool, 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 no_gc_sections(&mut self); + 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, natvis_debugger_visualizers: &[PathBuf]); + fn no_crt_objects(&mut self); + fn no_default_libraries(&mut self); + fn export_symbols(&mut self, tmpdir: &Path, crate_type: CrateType, symbols: &[String]); + 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 add_no_exec(&mut self) {} + fn add_as_needed(&mut self) {} + fn reset_per_library_state(&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, + target_cpu: &'a str, + hinted_static: bool, // Keeps track of the current hinting mode. + // Link as ld + is_ld: bool, +} + +impl<'a> GccLinker<'a> { + /// Passes an argument directly to the linker. + /// + /// When the linker is not ld-like such as when using a compiler as a linker, the argument is + /// prepended by `-Wl,`. + fn linker_arg(&mut self, arg: impl AsRef<OsStr>) -> &mut Self { + self.linker_args(&[arg]); + self + } + + /// Passes a series of arguments directly to the linker. + /// + /// When the linker is ld-like, the arguments are simply appended to the command. When the + /// linker is not ld-like such as when using a compiler as a linker, the arguments are joined by + /// commas to form an argument that is then prepended with `-Wl`. In this situation, only a + /// single argument is appended to the command to ensure that the order of the arguments is + /// preserved by the compiler. + fn linker_args(&mut self, args: &[impl AsRef<OsStr>]) -> &mut Self { + if self.is_ld { + args.into_iter().for_each(|a| { + self.cmd.arg(a); + }); + } else { + if !args.is_empty() { + let mut s = OsString::from("-Wl"); + for a in args { + s.push(","); + s.push(a); + } + self.cmd.arg(s); + } + } + 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.is_like_osx && !self.sess.target.is_like_wasm + } + + // 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 | config::OptLevel::Size | config::OptLevel::SizeMin => "O2", + config::OptLevel::Aggressive => "O3", + }; + + if let Some(path) = &self.sess.opts.unstable_opts.profile_sample_use { + self.linker_arg(&format!("-plugin-opt=sample-profile={}", path.display())); + }; + self.linker_args(&[ + &format!("-plugin-opt={}", opt_level), + &format!("-plugin-opt=mcpu={}", self.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.is_like_osx { + if !self.is_ld { + 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.unstable_opts.osx_rpath_install_name { + let mut rpath = OsString::from("@rpath/"); + rpath.push(out_filename.file_name().unwrap()); + self.linker_args(&[OsString::from("-install_name"), rpath]); + } + } else { + self.cmd.arg("-shared"); + if self.sess.target.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.staticlib_prefix, + file, + self.sess.target.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.linker_is_gnu { + self.cmd.arg("-no-pie"); + } + } + LinkOutputKind::DynamicPicExe => { + // noop on windows w/ gcc & ld, error w/ lld + if !self.sess.target.is_like_windows { + // `-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.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); + } + LinkOutputKind::WasiReactorExe => { + self.linker_args(&["--entry", "_initialize"]); + } + } + // 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.os == "vxworks" + && matches!( + output_kind, + LinkOutputKind::StaticNoPicExe + | LinkOutputKind::StaticPicExe + | LinkOutputKind::StaticDylib + ) + { + self.cmd.arg("--static-crt"); + } + } + + fn link_dylib(&mut self, lib: &str, verbatim: bool, as_needed: bool) { + if self.sess.target.os == "illumos" && lib == "c" { + // libc will be added via late_link_args on illumos so that it will + // appear last in the library search order. + // FIXME: This should be replaced by a more complete and generic + // mechanism for controlling the order of library arguments passed + // to the linker. + return; + } + if !as_needed { + if self.sess.target.is_like_osx { + // FIXME(81490): ld64 doesn't support these flags but macOS 11 + // has -needed-l{} / -needed_library {} + // but we have no way to detect that here. + self.sess.warn("`as-needed` modifier not implemented yet for ld64"); + } else if self.sess.target.linker_is_gnu && !self.sess.target.is_like_windows { + self.linker_arg("--no-as-needed"); + } else { + self.sess.warn("`as-needed` modifier not supported for current linker"); + } + } + self.hint_dynamic(); + self.cmd.arg(format!("-l{}{}", if verbatim { ":" } else { "" }, lib)); + if !as_needed { + if self.sess.target.is_like_osx { + // See above FIXME comment + } else if self.sess.target.linker_is_gnu && !self.sess.target.is_like_windows { + self.linker_arg("--as-needed"); + } + } + } + fn link_staticlib(&mut self, lib: &str, verbatim: bool) { + self.hint_static(); + self.cmd.arg(format!("-l{}{}", if verbatim { ":" } else { "" }, 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_args(&["-zrelro", "-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: &str, _path: &Path) { + self.hint_dynamic(); + self.cmd.arg(format!("-l{}", lib)); + } + + fn link_framework(&mut self, framework: &str, as_needed: bool) { + self.hint_dynamic(); + if !as_needed { + // FIXME(81490): ld64 as of macOS 11 supports the -needed_framework + // flag but we have no way to detect that here. + // self.cmd.arg("-needed_framework").arg(framework); + self.sess.warn("`as-needed` modifier not implemented yet for ld64"); + } + self.cmd.arg("-framework").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: &str, verbatim: bool, search_path: &[PathBuf]) { + self.hint_static(); + let target = &self.sess.target; + if !target.is_like_osx { + self.linker_arg("--whole-archive").cmd.arg(format!( + "-l{}{}", + if verbatim { ":" } else { "" }, + 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, verbatim, search_path, &self.sess); + self.linker_arg(&lib); + } + } + + fn link_whole_rlib(&mut self, lib: &Path) { + self.hint_static(); + if self.sess.target.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.is_like_osx { + self.linker_arg("-dead_strip"); + + // 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 (self.sess.target.linker_is_gnu || self.sess.target.is_like_wasm) + && !keep_metadata + { + self.linker_arg("--gc-sections"); + } + } + + fn no_gc_sections(&mut self) { + if self.sess.target.linker_is_gnu || self.sess.target.is_like_wasm { + self.linker_arg("--no-gc-sections"); + } + } + + fn optimize(&mut self) { + if !self.sess.target.linker_is_gnu && !self.sess.target.is_like_wasm { + 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.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, _: &[PathBuf]) { + // MacOS linker doesn't support stripping symbols directly anymore. + if self.sess.target.is_like_osx { + return; + } + + match strip { + Strip::None => {} + Strip::Debuginfo => { + self.linker_arg("--strip-debug"); + } + Strip::Symbols => { + self.linker_arg("--strip-all"); + } + } + } + + 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, symbols: &[String]) { + // Symbol visibility in object files typically takes care of this. + if crate_type == CrateType::Executable { + let should_export_executable_symbols = + self.sess.opts.unstable_opts.export_executable_symbols; + if self.sess.target.override_export_symbols.is_none() + && !should_export_executable_symbols + { + 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.limit_rdylib_exports { + return; + } + + // FIXME(#99978) hide #[no_mangle] symbols for proc-macros + + let is_windows = self.sess.target.is_like_windows; + let path = tmpdir.join(if is_windows { "list.def" } else { "list" }); + + debug!("EXPORTED SYMBOLS:"); + + if self.sess.target.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 symbols { + debug!(" _{}", sym); + writeln!(f, "_{}", sym)?; + } + }; + if let Err(e) = res { + self.sess.fatal(&format!("failed to write lib.def file: {}", e)); + } + } else if is_windows { + let res: io::Result<()> = try { + let mut f = BufWriter::new(File::create(&path)?); + + // .def file similar to MSVC one but without LIBRARY section + // because LD doesn't like when it's empty + writeln!(f, "EXPORTS")?; + for symbol in symbols { + debug!(" _{}", symbol); + writeln!(f, " {}", symbol)?; + } + }; + if let Err(e) = res { + self.sess.fatal(&format!("failed to write list.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 !symbols.is_empty() { + writeln!(f, " global:")?; + for sym in symbols { + 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.is_like_osx { + self.linker_args(&[OsString::from("-exported_symbols_list"), path.into()]); + } else if self.sess.target.is_like_solaris { + self.linker_args(&[OsString::from("-M"), path.into()]); + } else { + if is_windows { + self.linker_arg(path); + } else { + let mut arg = OsString::from("--version-script="); + arg.push(path); + self.linker_arg(arg); + } + } + } + + fn subsystem(&mut self, subsystem: &str) { + self.linker_arg("--subsystem"); + self.linker_arg(&subsystem); + } + + fn reset_per_library_state(&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) { + self.linker_arg("--eh-frame-hdr"); + } + + fn add_no_exec(&mut self) { + if self.sess.target.is_like_windows { + self.linker_arg("--nxcompat"); + } else if self.sess.target.linker_is_gnu { + self.linker_arg("-znoexecstack"); + } + } + + fn add_as_needed(&mut self) { + if self.sess.target.linker_is_gnu && !self.sess.target.is_like_windows { + self.linker_arg("--as-needed"); + } else if self.sess.target.is_like_solaris { + // -z ignore is the Solaris equivalent to the GNU ld --as-needed option + self.linker_args(&["-z", "ignore"]); + } + } +} + +pub struct MsvcLinker<'a> { + cmd: Command, + sess: &'a Session, +} + +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); + } + LinkOutputKind::WasiReactorExe => { + panic!("can't link as reactor on non-wasi target"); + } + } + } + + 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 no_gc_sections(&mut self) { + self.cmd.arg("/OPT:NOREF,NOICF"); + } + + fn link_dylib(&mut self, lib: &str, verbatim: bool, _as_needed: bool) { + self.cmd.arg(format!("{}{}", lib, if verbatim { "" } else { ".lib" })); + } + + fn link_rust_dylib(&mut self, lib: &str, 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 path.join(&name).exists() { + self.cmd.arg(name); + } + } + + fn link_staticlib(&mut self, lib: &str, verbatim: bool) { + self.cmd.arg(format!("{}{}", lib, if verbatim { "" } else { ".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: &str, _as_needed: bool) { + bug!("frameworks are not supported on windows") + } + + fn link_whole_staticlib(&mut self, lib: &str, verbatim: bool, _search_path: &[PathBuf]) { + self.cmd.arg(format!("/WHOLEARCHIVE:{}{}", lib, if verbatim { "" } else { ".lib" })); + } + fn link_whole_rlib(&mut self, path: &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, natvis_debugger_visualizers: &[PathBuf]) { + 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)); + } + } + } + } + + // This will cause the Microsoft linker to embed .natvis info for all crates into the PDB file + for path in natvis_debugger_visualizers { + let mut arg = OsString::from("/NATVIS:"); + arg.push(path); + self.cmd.arg(arg); + } + } + 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, symbols: &[String]) { + // Symbol visibility takes care of this typically + if crate_type == CrateType::Executable { + let should_export_executable_symbols = + self.sess.opts.unstable_opts.export_executable_symbols; + if !should_export_executable_symbols { + 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 symbols { + 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"); + } + } + + // MSVC doesn't need group indicators + fn group_start(&mut self) {} + fn group_end(&mut self) {} + + fn linker_plugin_lto(&mut self) { + // Do nothing + } + + fn add_no_exec(&mut self) { + self.cmd.arg("/NXCOMPAT"); + } +} + +pub struct EmLinker<'a> { + cmd: Command, + sess: &'a Session, +} + +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: &str, _verbatim: bool) { + self.cmd.arg("-l").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: &str, verbatim: bool, _as_needed: bool) { + // Emscripten always links statically + self.link_staticlib(lib, verbatim); + } + + fn link_whole_staticlib(&mut self, lib: &str, verbatim: bool, _search_path: &[PathBuf]) { + // not supported? + self.link_staticlib(lib, verbatim); + } + + fn link_whole_rlib(&mut self, lib: &Path) { + // not supported? + self.link_rlib(lib); + } + + fn link_rust_dylib(&mut self, lib: &str, _path: &Path) { + self.link_dylib(lib, false, true); + } + + 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: &str, _as_needed: bool) { + bug!("frameworks are not supported on Emscripten") + } + + fn gc_sections(&mut self, _keep_metadata: bool) { + // noop + } + + fn no_gc_sections(&mut self) { + // 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", + }); + } + + 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, _: &[PathBuf]) { + // Preserve names or generate source maps depending on debug info + self.cmd.arg(match self.sess.opts.debuginfo { + DebugInfo::None => "-g0", + DebugInfo::Limited => "--profiling-funcs", + DebugInfo::Full => "-g", + }); + } + + fn no_crt_objects(&mut self) {} + + fn no_default_libraries(&mut self) { + self.cmd.arg("-nodefaultlibs"); + } + + fn export_symbols(&mut self, _tmpdir: &Path, _crate_type: CrateType, symbols: &[String]) { + debug!("EXPORTED SYMBOLS:"); + + self.cmd.arg("-s"); + + let mut arg = OsString::from("EXPORTED_FUNCTIONS="); + let encoded = serde_json::to_string( + &symbols.iter().map(|sym| "_".to_owned() + sym).collect::<Vec<_>>(), + ) + .unwrap(); + debug!("{}", encoded); + + arg.push(encoded); + + self.cmd.arg(arg); + } + + fn subsystem(&mut self, _subsystem: &str) { + // noop + } + + // 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, +} + +impl<'a> WasmLd<'a> { + fn new(mut cmd: Command, sess: &'a Session) -> 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 } + } +} + +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"); + } + LinkOutputKind::WasiReactorExe => { + self.cmd.arg("--entry"); + self.cmd.arg("_initialize"); + } + } + } + + fn link_dylib(&mut self, lib: &str, _verbatim: bool, _as_needed: bool) { + self.cmd.arg("-l").arg(lib); + } + + fn link_staticlib(&mut self, lib: &str, _verbatim: bool) { + self.cmd.arg("-l").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: &str, _path: &Path) { + self.cmd.arg("-l").arg(lib); + } + + fn link_framework(&mut self, _framework: &str, _as_needed: bool) { + panic!("frameworks not supported") + } + + fn link_whole_staticlib(&mut self, lib: &str, _verbatim: bool, _search_path: &[PathBuf]) { + self.cmd.arg("-l").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 no_gc_sections(&mut self) { + self.cmd.arg("--no-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, _: &[PathBuf]) { + 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, symbols: &[String]) { + for sym in symbols { + self.cmd.arg("--export").arg(&sym); + } + + // LLD will hide these otherwise-internal symbols since it only exports + // symbols explicitly 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) {} + + // 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 + } +} + +/// Linker shepherd script for L4Re (Fiasco) +pub struct L4Bender<'a> { + cmd: Command, + sess: &'a Session, + hinted_static: bool, +} + +impl<'a> Linker for L4Bender<'a> { + fn link_dylib(&mut self, _lib: &str, _verbatim: bool, _as_needed: bool) { + bug!("dylibs are not supported on L4Re"); + } + fn link_staticlib(&mut self, lib: &str, _verbatim: bool) { + self.hint_static(); + self.cmd.arg(format!("-PC{}", 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) { + bug!("frameworks are not supported on L4Re"); + } + 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.cmd.arg("-zrelro"); + self.cmd.arg("-znow"); + } + + fn partial_relro(&mut self) { + self.cmd.arg("-zrelro"); + } + + fn no_relro(&mut self) { + self.cmd.arg("-znorelro"); + } + + fn cmd(&mut self) -> &mut Command { + &mut self.cmd + } + + fn set_output_kind(&mut self, _output_kind: LinkOutputKind, _out_filename: &Path) {} + + fn link_rust_dylib(&mut self, _: &str, _: &Path) { + panic!("Rust dylibs not supported"); + } + + fn link_framework(&mut self, _framework: &str, _as_needed: bool) { + bug!("frameworks not supported on L4Re"); + } + + fn link_whole_staticlib(&mut self, lib: &str, _verbatim: bool, _search_path: &[PathBuf]) { + self.hint_static(); + self.cmd.arg("--whole-archive").arg(format!("-l{}", lib)); + self.cmd.arg("--no-whole-archive"); + } + + fn link_whole_rlib(&mut self, lib: &Path) { + self.hint_static(); + self.cmd.arg("--whole-archive").arg(lib).arg("--no-whole-archive"); + } + + fn gc_sections(&mut self, keep_metadata: bool) { + if !keep_metadata { + self.cmd.arg("--gc-sections"); + } + } + + fn no_gc_sections(&mut self) { + self.cmd.arg("--no-gc-sections"); + } + + fn optimize(&mut self) { + // 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.cmd.arg("-O1"); + } + } + + fn pgo_gen(&mut self) {} + + fn debuginfo(&mut self, strip: Strip, _: &[PathBuf]) { + match strip { + Strip::None => {} + Strip::Debuginfo => { + self.cmd().arg("--strip-debug"); + } + Strip::Symbols => { + self.cmd().arg("--strip-all"); + } + } + } + + fn no_default_libraries(&mut self) { + self.cmd.arg("-nostdlib"); + } + + fn export_symbols(&mut self, _: &Path, _: CrateType, _: &[String]) { + // ToDo, not implemented, copy from GCC + self.sess.warn("exporting symbols not implemented yet for L4Bender"); + return; + } + + fn subsystem(&mut self, subsystem: &str) { + self.cmd.arg(&format!("--subsystem {}", subsystem)); + } + + fn reset_per_library_state(&mut self) { + self.hint_static(); // Reset to default before returning the composed command line. + } + + fn group_start(&mut self) { + self.cmd.arg("--start-group"); + } + + fn group_end(&mut self) { + self.cmd.arg("--end-group"); + } + + fn linker_plugin_lto(&mut self) {} + + fn control_flow_guard(&mut self) {} + + fn no_crt_objects(&mut self) {} +} + +impl<'a> L4Bender<'a> { + pub fn new(cmd: Command, sess: &'a Session) -> L4Bender<'a> { + L4Bender { cmd: cmd, sess: sess, hinted_static: false } + } + + fn hint_static(&mut self) { + if !self.hinted_static { + self.cmd.arg("-static"); + self.hinted_static = true; + } + } +} + +fn for_each_exported_symbols_include_dep<'tcx>( + tcx: TyCtxt<'tcx>, + crate_type: CrateType, + mut callback: impl FnMut(ExportedSymbol<'tcx>, SymbolExportInfo, CrateNum), +) { + for &(symbol, info) in tcx.exported_symbols(LOCAL_CRATE).iter() { + callback(symbol, info, LOCAL_CRATE); + } + + let formats = tcx.dependency_formats(()); + 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 { + for &(symbol, info) in tcx.exported_symbols(cnum).iter() { + callback(symbol, info, cnum); + } + } + } +} + +pub(crate) fn exported_symbols(tcx: TyCtxt<'_>, crate_type: CrateType) -> Vec<String> { + if let Some(ref exports) = tcx.sess.target.override_export_symbols { + return exports.iter().map(ToString::to_string).collect(); + } + + let mut symbols = Vec::new(); + + let export_threshold = symbol_export::crates_export_threshold(&[crate_type]); + for_each_exported_symbols_include_dep(tcx, crate_type, |symbol, info, cnum| { + if info.level.is_below_threshold(export_threshold) { + symbols.push(symbol_export::symbol_name_for_instance_in_crate(tcx, symbol, cnum)); + } + }); + + symbols +} + +pub(crate) fn linked_symbols( + tcx: TyCtxt<'_>, + crate_type: CrateType, +) -> Vec<(String, SymbolExportKind)> { + match crate_type { + CrateType::Executable | CrateType::Cdylib | CrateType::Dylib => (), + CrateType::Staticlib | CrateType::ProcMacro | CrateType::Rlib => { + return Vec::new(); + } + } + + let mut symbols = Vec::new(); + + let export_threshold = symbol_export::crates_export_threshold(&[crate_type]); + for_each_exported_symbols_include_dep(tcx, crate_type, |symbol, info, cnum| { + if info.level.is_below_threshold(export_threshold) || info.used { + symbols.push(( + symbol_export::linking_symbol_name_for_instance_in_crate(tcx, symbol, cnum), + info.kind, + )); + } + }); + + 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, _: &[PathBuf]) { + 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 link_dylib(&mut self, _lib: &str, _verbatim: bool, _as_needed: bool) { + panic!("external dylibs not supported") + } + + fn link_rust_dylib(&mut self, _lib: &str, _path: &Path) { + panic!("external dylibs not supported") + } + + fn link_staticlib(&mut self, _lib: &str, _verbatim: bool) { + panic!("staticlibs not supported") + } + + fn link_whole_staticlib(&mut self, _lib: &str, _verbatim: bool, _search_path: &[PathBuf]) { + panic!("staticlibs not supported") + } + + fn framework_path(&mut self, _path: &Path) { + panic!("frameworks not supported") + } + + fn link_framework(&mut self, _framework: &str, _as_needed: bool) { + 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 no_gc_sections(&mut self) {} + + 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, _symbols: &[String]) {} + + fn subsystem(&mut self, _subsystem: &str) {} + + fn group_start(&mut self) {} + + fn group_end(&mut self) {} + + fn linker_plugin_lto(&mut self) {} +} + +pub struct BpfLinker<'a> { + cmd: Command, + sess: &'a Session, +} + +impl<'a> Linker for BpfLinker<'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(path); + } + + fn link_whole_rlib(&mut self, path: &Path) { + self.cmd.arg(path); + } + + fn include_path(&mut self, path: &Path) { + self.cmd.arg("-L").arg(path); + } + + fn debuginfo(&mut self, _strip: Strip, _: &[PathBuf]) { + self.cmd.arg("--debug"); + } + + fn add_object(&mut self, path: &Path) { + self.cmd.arg(path); + } + + fn optimize(&mut self) { + 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", + }); + } + + fn output_filename(&mut self, path: &Path) { + self.cmd.arg("-o").arg(path); + } + + fn link_dylib(&mut self, _lib: &str, _verbatim: bool, _as_needed: bool) { + panic!("external dylibs not supported") + } + + fn link_rust_dylib(&mut self, _lib: &str, _path: &Path) { + panic!("external dylibs not supported") + } + + fn link_staticlib(&mut self, _lib: &str, _verbatim: bool) { + panic!("staticlibs not supported") + } + + fn link_whole_staticlib(&mut self, _lib: &str, _verbatim: bool, _search_path: &[PathBuf]) { + panic!("staticlibs not supported") + } + + fn framework_path(&mut self, _path: &Path) { + panic!("frameworks not supported") + } + + fn link_framework(&mut self, _framework: &str, _as_needed: bool) { + 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 no_gc_sections(&mut self) {} + + 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, symbols: &[String]) { + let path = tmpdir.join("symbols"); + let res: io::Result<()> = try { + let mut f = BufWriter::new(File::create(&path)?); + for sym in symbols { + writeln!(f, "{}", sym)?; + } + }; + if let Err(e) = res { + self.sess.fatal(&format!("failed to write symbols file: {}", e)); + } else { + self.cmd.arg("--export-symbols").arg(&path); + } + } + + fn subsystem(&mut self, _subsystem: &str) {} + + fn group_start(&mut self) {} + + fn group_end(&mut self) {} + + fn linker_plugin_lto(&mut self) {} +} |