| /// For all the linkers we support, and information they might |
| /// need out of the shared crate context before we get rid of it. |
| |
| use rustc::session::{Session, filesearch}; |
| use rustc::session::config::{ |
| self, RUST_CGU_EXT, DebugInfo, OutputFilenames, OutputType, PrintRequest, Sanitizer |
| }; |
| use rustc::session::search_paths::PathKind; |
| use rustc::middle::dependency_format::Linkage; |
| use rustc::middle::cstore::{EncodedMetadata, LibSource, NativeLibrary, NativeLibraryKind}; |
| use rustc::util::common::{time, time_ext}; |
| use rustc::hir::def_id::CrateNum; |
| use rustc_data_structures::fx::FxHashSet; |
| use rustc_fs_util::fix_windows_verbatim_for_gcc; |
| use rustc_target::spec::{PanicStrategy, RelroLevel, LinkerFlavor}; |
| use syntax::symbol::Symbol; |
| |
| use crate::{METADATA_FILENAME, RLIB_BYTECODE_EXTENSION, CrateInfo, CodegenResults}; |
| use super::archive::ArchiveBuilder; |
| use super::command::Command; |
| use super::linker::Linker; |
| use super::rpath::{self, RPathConfig}; |
| |
| use cc::windows_registry; |
| use tempfile::{Builder as TempFileBuilder, TempDir}; |
| |
| use std::ascii; |
| use std::char; |
| use std::fmt; |
| use std::fs; |
| use std::io; |
| use std::path::{Path, PathBuf}; |
| use std::process::{Output, Stdio, ExitStatus}; |
| use std::str; |
| use std::env; |
| use std::ffi::OsString; |
| |
| pub use rustc_codegen_utils::link::*; |
| |
| pub fn remove(sess: &Session, path: &Path) { |
| if let Err(e) = fs::remove_file(path) { |
| sess.err(&format!("failed to remove {}: {}", |
| path.display(), |
| e)); |
| } |
| } |
| |
| /// Performs the linkage portion of the compilation phase. This will generate all |
| /// of the requested outputs for this compilation session. |
| pub fn link_binary<'a, B: ArchiveBuilder<'a>>(sess: &'a Session, |
| codegen_results: &CodegenResults, |
| outputs: &OutputFilenames, |
| crate_name: &str, |
| target_cpu: &str) { |
| let output_metadata = sess.opts.output_types.contains_key(&OutputType::Metadata); |
| for &crate_type in sess.crate_types.borrow().iter() { |
| // Ignore executable crates if we have -Z no-codegen, as they will error. |
| if (sess.opts.debugging_opts.no_codegen || !sess.opts.output_types.should_codegen()) && |
| !output_metadata && |
| crate_type == config::CrateType::Executable { |
| continue; |
| } |
| |
| if invalid_output_for_target(sess, crate_type) { |
| bug!("invalid output type `{:?}` for target os `{}`", |
| crate_type, sess.opts.target_triple); |
| } |
| |
| for obj in codegen_results.modules.iter().filter_map(|m| m.object.as_ref()) { |
| check_file_is_writeable(obj, sess); |
| } |
| |
| let tmpdir = TempFileBuilder::new().prefix("rustc").tempdir().unwrap_or_else(|err| |
| sess.fatal(&format!("couldn't create a temp dir: {}", err))); |
| |
| if outputs.outputs.should_codegen() { |
| let out_filename = out_filename(sess, crate_type, outputs, crate_name); |
| match crate_type { |
| config::CrateType::Rlib => { |
| link_rlib::<B>(sess, |
| codegen_results, |
| RlibFlavor::Normal, |
| &out_filename, |
| &tmpdir).build(); |
| } |
| config::CrateType::Staticlib => { |
| link_staticlib::<B>(sess, codegen_results, &out_filename, &tmpdir); |
| } |
| _ => { |
| link_natively::<B>( |
| sess, |
| crate_type, |
| &out_filename, |
| codegen_results, |
| tmpdir.path(), |
| target_cpu, |
| ); |
| } |
| } |
| if sess.opts.json_artifact_notifications { |
| sess.parse_sess.span_diagnostic.emit_artifact_notification(&out_filename, "link"); |
| } |
| } |
| |
| if sess.opts.cg.save_temps { |
| let _ = tmpdir.into_path(); |
| } |
| } |
| |
| // Remove the temporary object file and metadata if we aren't saving temps |
| if !sess.opts.cg.save_temps { |
| if sess.opts.output_types.should_codegen() && !preserve_objects_for_their_debuginfo(sess) { |
| for obj in codegen_results.modules.iter().filter_map(|m| m.object.as_ref()) { |
| remove(sess, obj); |
| } |
| } |
| for obj in codegen_results.modules.iter().filter_map(|m| m.bytecode_compressed.as_ref()) { |
| remove(sess, obj); |
| } |
| if let Some(ref metadata_module) = codegen_results.metadata_module { |
| if let Some(ref obj) = metadata_module.object { |
| remove(sess, obj); |
| } |
| } |
| if let Some(ref allocator_module) = codegen_results.allocator_module { |
| if let Some(ref obj) = allocator_module.object { |
| remove(sess, obj); |
| } |
| if let Some(ref bc) = allocator_module.bytecode_compressed { |
| remove(sess, bc); |
| } |
| } |
| } |
| } |
| |
| // 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(sess: &Session, linker: &Path, flavor: LinkerFlavor) -> (PathBuf, Command) { |
| 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.target.options.linker.is_none() => |
| { |
| Command::new(msvc_tool.as_ref().map(|t| t.path()).unwrap_or(linker)) |
| }, |
| _ => 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.target; |
| if flavor == LinkerFlavor::Msvc && t.target_vendor == "uwp" { |
| if let Some(ref tool) = msvc_tool { |
| let original_path = tool.path(); |
| if let Some(ref root_lib_path) = original_path.ancestors().skip(4).next() { |
| let arch = match t.arch.as_str() { |
| "x86_64" => Some("x64".to_string()), |
| "x86" => Some("x86".to_string()), |
| "aarch64" => Some("arm64".to_string()), |
| _ => None, |
| }; |
| if let Some(ref a) = arch { |
| let mut arg = OsString::from("/LIBPATH:"); |
| arg.push(format!("{}\\lib\\{}\\store", root_lib_path.display(), a.to_string())); |
| 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.host_filesearch(PathKind::All) |
| .get_tools_search_paths(); |
| let mut msvc_changed_path = false; |
| if sess.target.target.options.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()); |
| |
| (linker.to_path_buf(), cmd) |
| } |
| |
| pub fn each_linked_rlib(sess: &Session, |
| info: &CrateInfo, |
| f: &mut dyn FnMut(CrateNum, &Path)) -> Result<(), String> { |
| let crates = info.used_crates_static.iter(); |
| let fmts = sess.dependency_formats.borrow(); |
| let fmts = fmts.get(&config::CrateType::Executable) |
| .or_else(|| fmts.get(&config::CrateType::Staticlib)) |
| .or_else(|| fmts.get(&config::CrateType::Cdylib)) |
| .or_else(|| fmts.get(&config::CrateType::ProcMacro)); |
| let fmts = match fmts { |
| Some(f) => f, |
| None => return Err("could not find formats for rlibs".to_string()) |
| }; |
| for &(cnum, ref path) in crates { |
| match fmts.get(cnum.as_usize() - 1) { |
| Some(&Linkage::NotLinked) | |
| Some(&Linkage::IncludedFromDylib) => continue, |
| Some(_) => {} |
| None => return Err("could not find formats for rlibs".to_string()) |
| } |
| let name = &info.crate_name[&cnum]; |
| let path = match *path { |
| LibSource::Some(ref p) => p, |
| LibSource::MetadataOnly => { |
| return Err(format!("could not find rlib for: `{}`, found rmeta (metadata) file", |
| name)) |
| } |
| LibSource::None => { |
| return Err(format!("could not find rlib for: `{}`", name)) |
| } |
| }; |
| f(cnum, &path); |
| } |
| Ok(()) |
| } |
| |
| /// We use a temp directory here to avoid races between concurrent rustc processes, |
| /// such as builds in the same directory using the same filename for metadata while |
| /// building an `.rlib` (stomping over one another), or writing an `.rmeta` into a |
| /// directory being searched for `extern crate` (observing an incomplete file). |
| /// The returned path is the temporary file containing the complete metadata. |
| pub fn emit_metadata<'a>( |
| sess: &'a Session, |
| metadata: &EncodedMetadata, |
| tmpdir: &TempDir |
| ) -> PathBuf { |
| let out_filename = tmpdir.path().join(METADATA_FILENAME); |
| let result = fs::write(&out_filename, &metadata.raw_data); |
| |
| if let Err(e) = result { |
| sess.fatal(&format!("failed to write {}: {}", out_filename.display(), e)); |
| } |
| |
| out_filename |
| } |
| |
| // Create an 'rlib' |
| // |
| // An rlib in its current incarnation is essentially a renamed .a file. The |
| // rlib primarily contains the object file of the crate, but it also contains |
| // all of the object files from native libraries. This is done by unzipping |
| // native libraries and inserting all of the contents into this archive. |
| fn link_rlib<'a, B: ArchiveBuilder<'a>>(sess: &'a Session, |
| codegen_results: &CodegenResults, |
| flavor: RlibFlavor, |
| out_filename: &Path, |
| tmpdir: &TempDir) -> B { |
| info!("preparing rlib to {:?}", out_filename); |
| let mut ab = <B as ArchiveBuilder>::new(sess, out_filename, None); |
| |
| for obj in codegen_results.modules.iter().filter_map(|m| m.object.as_ref()) { |
| ab.add_file(obj); |
| } |
| |
| // Note that in this loop we are ignoring the value of `lib.cfg`. That is, |
| // we may not be configured to actually include a static library if we're |
| // adding it here. That's because later when we consume this rlib we'll |
| // decide whether we actually needed the static library or not. |
| // |
| // To do this "correctly" we'd need to keep track of which libraries added |
| // which object files to the archive. We don't do that here, however. The |
| // #[link(cfg(..))] feature is unstable, though, and only intended to get |
| // liblibc working. In that sense the check below just indicates that if |
| // there are any libraries we want to omit object files for at link time we |
| // just exclude all custom object files. |
| // |
| // Eventually if we want to stabilize or flesh out the #[link(cfg(..))] |
| // feature then we'll need to figure out how to record what objects were |
| // loaded from the libraries found here and then encode that into the |
| // metadata of the rlib we're generating somehow. |
| for lib in codegen_results.crate_info.used_libraries.iter() { |
| match lib.kind { |
| NativeLibraryKind::NativeStatic => {} |
| NativeLibraryKind::NativeStaticNobundle | |
| NativeLibraryKind::NativeFramework | |
| NativeLibraryKind::NativeUnknown => continue, |
| } |
| if let Some(name) = lib.name { |
| ab.add_native_library(name); |
| } |
| } |
| |
| // After adding all files to the archive, we need to update the |
| // symbol table of the archive. |
| ab.update_symbols(); |
| |
| // Note that it is important that we add all of our non-object "magical |
| // files" *after* all of the object files in the archive. The reason for |
| // this is as follows: |
| // |
| // * When performing LTO, this archive will be modified to remove |
| // objects from above. The reason for this is described below. |
| // |
| // * When the system linker looks at an archive, it will attempt to |
| // determine the architecture of the archive in order to see whether its |
| // linkable. |
| // |
| // The algorithm for this detection is: iterate over the files in the |
| // archive. Skip magical SYMDEF names. Interpret the first file as an |
| // object file. Read architecture from the object file. |
| // |
| // * As one can probably see, if "metadata" and "foo.bc" were placed |
| // before all of the objects, then the architecture of this archive would |
| // not be correctly inferred once 'foo.o' is removed. |
| // |
| // Basically, all this means is that this code should not move above the |
| // code above. |
| match flavor { |
| RlibFlavor::Normal => { |
| // Instead of putting the metadata in an object file section, rlibs |
| // contain the metadata in a separate file. |
| ab.add_file(&emit_metadata(sess, &codegen_results.metadata, tmpdir)); |
| |
| // For LTO purposes, the bytecode of this library is also inserted |
| // into the archive. |
| for bytecode in codegen_results |
| .modules |
| .iter() |
| .filter_map(|m| m.bytecode_compressed.as_ref()) |
| { |
| ab.add_file(bytecode); |
| } |
| |
| // After adding all files to the archive, we need to update the |
| // symbol table of the archive. This currently dies on macOS (see |
| // #11162), and isn't necessary there anyway |
| if !sess.target.target.options.is_like_osx { |
| ab.update_symbols(); |
| } |
| } |
| |
| RlibFlavor::StaticlibBase => { |
| let obj = codegen_results.allocator_module |
| .as_ref() |
| .and_then(|m| m.object.as_ref()); |
| if let Some(obj) = obj { |
| ab.add_file(obj); |
| } |
| } |
| } |
| |
| ab |
| } |
| |
| // Create a static archive |
| // |
| // This is essentially the same thing as an rlib, but it also involves adding |
| // all of the upstream crates' objects into the archive. This will slurp in |
| // all of the native libraries of upstream dependencies as well. |
| // |
| // Additionally, there's no way for us to link dynamic libraries, so we warn |
| // about all dynamic library dependencies that they're not linked in. |
| // |
| // There's no need to include metadata in a static archive, so ensure to not |
| // link in the metadata object file (and also don't prepare the archive with a |
| // metadata file). |
| fn link_staticlib<'a, B: ArchiveBuilder<'a>>(sess: &'a Session, |
| codegen_results: &CodegenResults, |
| out_filename: &Path, |
| tempdir: &TempDir) { |
| let mut ab = link_rlib::<B>(sess, |
| codegen_results, |
| RlibFlavor::StaticlibBase, |
| out_filename, |
| tempdir); |
| let mut all_native_libs = vec![]; |
| |
| let res = each_linked_rlib(sess, &codegen_results.crate_info, &mut |cnum, path| { |
| let name = &codegen_results.crate_info.crate_name[&cnum]; |
| let native_libs = &codegen_results.crate_info.native_libraries[&cnum]; |
| |
| // Here when we include the rlib into our staticlib we need to make a |
| // decision whether to include the extra object files along the way. |
| // These extra object files come from statically included native |
| // libraries, but they may be cfg'd away with #[link(cfg(..))]. |
| // |
| // This unstable feature, though, only needs liblibc to work. The only |
| // use case there is where musl is statically included in liblibc.rlib, |
| // so if we don't want the included version we just need to skip it. As |
| // a result the logic here is that if *any* linked library is cfg'd away |
| // we just skip all object files. |
| // |
| // Clearly this is not sufficient for a general purpose feature, and |
| // we'd want to read from the library's metadata to determine which |
| // object files come from where and selectively skip them. |
| let skip_object_files = native_libs.iter().any(|lib| { |
| lib.kind == NativeLibraryKind::NativeStatic && !relevant_lib(sess, lib) |
| }); |
| ab.add_rlib(path, |
| &name.as_str(), |
| are_upstream_rust_objects_already_included(sess) && |
| !ignored_for_lto(sess, &codegen_results.crate_info, cnum), |
| skip_object_files).unwrap(); |
| |
| all_native_libs.extend(codegen_results.crate_info.native_libraries[&cnum].iter().cloned()); |
| }); |
| if let Err(e) = res { |
| sess.fatal(&e); |
| } |
| |
| ab.update_symbols(); |
| ab.build(); |
| |
| if !all_native_libs.is_empty() { |
| if sess.opts.prints.contains(&PrintRequest::NativeStaticLibs) { |
| print_native_static_libs(sess, &all_native_libs); |
| } |
| } |
| } |
| |
| // Create a dynamic library or executable |
| // |
| // This will invoke the system linker/cc to create the resulting file. This |
| // links to all upstream files as well. |
| fn link_natively<'a, B: ArchiveBuilder<'a>>(sess: &'a Session, |
| crate_type: config::CrateType, |
| out_filename: &Path, |
| codegen_results: &CodegenResults, |
| tmpdir: &Path, |
| target_cpu: &str) { |
| info!("preparing {:?} to {:?}", crate_type, out_filename); |
| let (linker, flavor) = linker_and_flavor(sess); |
| |
| // The invocations of cc share some flags across platforms |
| let (pname, mut cmd) = get_linker(sess, &linker, flavor); |
| |
| if let Some(args) = sess.target.target.options.pre_link_args.get(&flavor) { |
| cmd.args(args); |
| } |
| if let Some(args) = sess.target.target.options.pre_link_args_crt.get(&flavor) { |
| if sess.crt_static() { |
| cmd.args(args); |
| } |
| } |
| if let Some(ref args) = sess.opts.debugging_opts.pre_link_args { |
| cmd.args(args); |
| } |
| cmd.args(&sess.opts.debugging_opts.pre_link_arg); |
| |
| if sess.target.target.options.is_like_fuchsia { |
| let prefix = match sess.opts.debugging_opts.sanitizer { |
| Some(Sanitizer::Address) => "asan/", |
| _ => "", |
| }; |
| cmd.arg(format!("--dynamic-linker={}ld.so.1", prefix)); |
| } |
| |
| let pre_link_objects = if crate_type == config::CrateType::Executable { |
| &sess.target.target.options.pre_link_objects_exe |
| } else { |
| &sess.target.target.options.pre_link_objects_dll |
| }; |
| for obj in pre_link_objects { |
| cmd.arg(get_file_path(sess, obj)); |
| } |
| |
| if crate_type == config::CrateType::Executable && sess.crt_static() { |
| for obj in &sess.target.target.options.pre_link_objects_exe_crt { |
| cmd.arg(get_file_path(sess, obj)); |
| } |
| } |
| |
| if sess.target.target.options.is_like_emscripten { |
| cmd.arg("-s"); |
| cmd.arg(if sess.panic_strategy() == PanicStrategy::Abort { |
| "DISABLE_EXCEPTION_CATCHING=1" |
| } else { |
| "DISABLE_EXCEPTION_CATCHING=0" |
| }); |
| } |
| |
| { |
| let mut linker = codegen_results.linker_info.to_linker(cmd, &sess, flavor, target_cpu); |
| link_args::<B>(&mut *linker, flavor, sess, crate_type, tmpdir, |
| out_filename, codegen_results); |
| cmd = linker.finalize(); |
| } |
| if let Some(args) = sess.target.target.options.late_link_args.get(&flavor) { |
| cmd.args(args); |
| } |
| for obj in &sess.target.target.options.post_link_objects { |
| cmd.arg(get_file_path(sess, obj)); |
| } |
| if sess.crt_static() { |
| for obj in &sess.target.target.options.post_link_objects_crt { |
| cmd.arg(get_file_path(sess, obj)); |
| } |
| } |
| if let Some(args) = sess.target.target.options.post_link_args.get(&flavor) { |
| cmd.args(args); |
| } |
| for &(ref k, ref v) in &sess.target.target.options.link_env { |
| cmd.env(k, v); |
| } |
| for k in &sess.target.target.options.link_env_remove { |
| cmd.env_remove(k); |
| } |
| |
| if sess.opts.debugging_opts.print_link_args { |
| println!("{:?}", &cmd); |
| } |
| |
| // May have not found libraries in the right formats. |
| sess.abort_if_errors(); |
| |
| // Invoke the system linker |
| info!("{:?}", &cmd); |
| let retry_on_segfault = env::var("RUSTC_RETRY_LINKER_ON_SEGFAULT").is_ok(); |
| let mut prog; |
| let mut i = 0; |
| loop { |
| i += 1; |
| prog = time(sess, "running linker", || { |
| exec_linker(sess, &mut cmd, out_filename, tmpdir) |
| }); |
| let output = match prog { |
| Ok(ref output) => output, |
| Err(_) => break, |
| }; |
| if output.status.success() { |
| break |
| } |
| let mut out = output.stderr.clone(); |
| out.extend(&output.stdout); |
| let out = String::from_utf8_lossy(&out); |
| |
| // Check to see if the link failed with "unrecognized command line option: |
| // '-no-pie'" for gcc or "unknown argument: '-no-pie'" for clang. If so, |
| // reperform the link step without the -no-pie option. This is safe because |
| // if the linker doesn't support -no-pie then it should not default to |
| // linking executables as pie. Different versions of gcc seem to use |
| // different quotes in the error message so don't check for them. |
| if sess.target.target.options.linker_is_gnu && |
| flavor != LinkerFlavor::Ld && |
| (out.contains("unrecognized command line option") || |
| out.contains("unknown argument")) && |
| out.contains("-no-pie") && |
| cmd.get_args().iter().any(|e| e.to_string_lossy() == "-no-pie") { |
| info!("linker output: {:?}", out); |
| warn!("Linker does not support -no-pie command line option. Retrying without."); |
| for arg in cmd.take_args() { |
| if arg.to_string_lossy() != "-no-pie" { |
| cmd.arg(arg); |
| } |
| } |
| info!("{:?}", &cmd); |
| continue; |
| } |
| |
| // Here's a terribly awful hack that really shouldn't be present in any |
| // compiler. Here an environment variable is supported to automatically |
| // retry the linker invocation if the linker looks like it segfaulted. |
| // |
| // Gee that seems odd, normally segfaults are things we want to know |
| // about! Unfortunately though in rust-lang/rust#38878 we're |
| // experiencing the linker segfaulting on Travis quite a bit which is |
| // causing quite a bit of pain to land PRs when they spuriously fail |
| // due to a segfault. |
| // |
| // The issue #38878 has some more debugging information on it as well, |
| // but this unfortunately looks like it's just a race condition in |
| // macOS's linker with some thread pool working in the background. It |
| // seems that no one currently knows a fix for this so in the meantime |
| // we're left with this... |
| if !retry_on_segfault || i > 3 { |
| break |
| } |
| let msg_segv = "clang: error: unable to execute command: Segmentation fault: 11"; |
| let msg_bus = "clang: error: unable to execute command: Bus error: 10"; |
| if out.contains(msg_segv) || out.contains(msg_bus) { |
| warn!( |
| "looks like the linker segfaulted when we tried to call it, \ |
| automatically retrying again. cmd = {:?}, out = {}.", |
| cmd, |
| out, |
| ); |
| continue; |
| } |
| |
| if is_illegal_instruction(&output.status) { |
| warn!( |
| "looks like the linker hit an illegal instruction when we \ |
| tried to call it, automatically retrying again. cmd = {:?}, ]\ |
| out = {}, status = {}.", |
| cmd, |
| out, |
| output.status, |
| ); |
| continue; |
| } |
| |
| #[cfg(unix)] |
| fn is_illegal_instruction(status: &ExitStatus) -> bool { |
| use std::os::unix::prelude::*; |
| status.signal() == Some(libc::SIGILL) |
| } |
| |
| #[cfg(windows)] |
| fn is_illegal_instruction(_status: &ExitStatus) -> bool { |
| false |
| } |
| } |
| |
| match prog { |
| Ok(prog) => { |
| fn escape_string(s: &[u8]) -> String { |
| str::from_utf8(s).map(|s| s.to_owned()) |
| .unwrap_or_else(|_| { |
| let mut x = "Non-UTF-8 output: ".to_string(); |
| x.extend(s.iter() |
| .flat_map(|&b| ascii::escape_default(b)) |
| .map(char::from)); |
| x |
| }) |
| } |
| if !prog.status.success() { |
| let mut output = prog.stderr.clone(); |
| output.extend_from_slice(&prog.stdout); |
| sess.struct_err(&format!("linking with `{}` failed: {}", |
| pname.display(), |
| prog.status)) |
| .note(&format!("{:?}", &cmd)) |
| .note(&escape_string(&output)) |
| .emit(); |
| sess.abort_if_errors(); |
| } |
| info!("linker stderr:\n{}", escape_string(&prog.stderr)); |
| info!("linker stdout:\n{}", escape_string(&prog.stdout)); |
| }, |
| Err(e) => { |
| let linker_not_found = e.kind() == io::ErrorKind::NotFound; |
| |
| let mut linker_error = { |
| if linker_not_found { |
| sess.struct_err(&format!("linker `{}` not found", pname.display())) |
| } else { |
| sess.struct_err(&format!("could not exec the linker `{}`", pname.display())) |
| } |
| }; |
| |
| linker_error.note(&e.to_string()); |
| |
| if !linker_not_found { |
| linker_error.note(&format!("{:?}", &cmd)); |
| } |
| |
| linker_error.emit(); |
| |
| if sess.target.target.options.is_like_msvc && linker_not_found { |
| sess.note_without_error( |
| "the msvc targets depend on the msvc linker \ |
| but `link.exe` was not found", |
| ); |
| sess.note_without_error( |
| "please ensure that VS 2013, VS 2015, VS 2017 or VS 2019 \ |
| was installed with the Visual C++ option", |
| ); |
| } |
| sess.abort_if_errors(); |
| } |
| } |
| |
| |
| // On macOS, debuggers need this utility to get run to do some munging of |
| // the symbols. Note, though, that if the object files are being preserved |
| // for their debug information there's no need for us to run dsymutil. |
| if sess.target.target.options.is_like_osx && |
| sess.opts.debuginfo != DebugInfo::None && |
| !preserve_objects_for_their_debuginfo(sess) |
| { |
| if let Err(e) = Command::new("dsymutil").arg(out_filename).output() { |
| sess.fatal(&format!("failed to run dsymutil: {}", e)) |
| } |
| } |
| } |
| |
| /// Returns a boolean indicating whether the specified crate should be ignored |
| /// during LTO. |
| /// |
| /// Crates ignored during LTO are not lumped together in the "massive object |
| /// file" that we create and are linked in their normal rlib states. See |
| /// comments below for what crates do not participate in LTO. |
| /// |
| /// It's unusual for a crate to not participate in LTO. Typically only |
| /// compiler-specific and unstable crates have a reason to not participate in |
| /// LTO. |
| pub fn ignored_for_lto(sess: &Session, info: &CrateInfo, cnum: CrateNum) -> bool { |
| // If our target enables builtin function lowering in LLVM then the |
| // crates providing these functions don't participate in LTO (e.g. |
| // no_builtins or compiler builtins crates). |
| !sess.target.target.options.no_builtins && |
| (info.compiler_builtins == Some(cnum) || info.is_no_builtins.contains(&cnum)) |
| } |
| |
| pub fn linker_and_flavor(sess: &Session) -> (PathBuf, LinkerFlavor) { |
| fn infer_from( |
| sess: &Session, |
| linker: Option<PathBuf>, |
| flavor: Option<LinkerFlavor>, |
| ) -> Option<(PathBuf, LinkerFlavor)> { |
| match (linker, flavor) { |
| (Some(linker), Some(flavor)) => Some((linker, flavor)), |
| // only the linker flavor is known; use the default linker for the selected flavor |
| (None, Some(flavor)) => Some((PathBuf::from(match flavor { |
| LinkerFlavor::Em => if cfg!(windows) { "emcc.bat" } else { "emcc" }, |
| LinkerFlavor::Gcc => "cc", |
| LinkerFlavor::Ld => "ld", |
| LinkerFlavor::Msvc => "link.exe", |
| LinkerFlavor::Lld(_) => "lld", |
| LinkerFlavor::PtxLinker => "rust-ptx-linker", |
| }), flavor)), |
| (Some(linker), None) => { |
| let stem = linker |
| .file_stem() |
| .and_then(|stem| stem.to_str()) |
| .unwrap_or_else(|| { |
| sess.fatal("couldn't extract file stem from specified linker") |
| }); |
| |
| let flavor = if stem == "emcc" { |
| LinkerFlavor::Em |
| } else if stem == "gcc" |
| || stem.ends_with("-gcc") |
| || stem == "clang" |
| || stem.ends_with("-clang") |
| { |
| LinkerFlavor::Gcc |
| } else if stem == "ld" || stem == "ld.lld" || stem.ends_with("-ld") { |
| LinkerFlavor::Ld |
| } else if stem == "link" || stem == "lld-link" { |
| LinkerFlavor::Msvc |
| } else if stem == "lld" || stem == "rust-lld" { |
| LinkerFlavor::Lld(sess.target.target.options.lld_flavor) |
| } else { |
| // fall back to the value in the target spec |
| sess.target.target.linker_flavor |
| }; |
| |
| Some((linker, flavor)) |
| }, |
| (None, None) => None, |
| } |
| } |
| |
| // linker and linker flavor specified via command line have precedence over what the target |
| // specification specifies |
| if let Some(ret) = infer_from(sess, sess.opts.cg.linker.clone(), sess.opts.cg.linker_flavor) { |
| return ret; |
| } |
| |
| if let Some(ret) = infer_from( |
| sess, |
| sess.target.target.options.linker.clone().map(PathBuf::from), |
| Some(sess.target.target.linker_flavor), |
| ) { |
| return ret; |
| } |
| |
| bug!("Not enough information provided to determine how to invoke the linker"); |
| } |
| |
| /// Returns a boolean indicating whether we should preserve the object files on |
| /// the filesystem for their debug information. This is often useful with |
| /// split-dwarf like schemes. |
| pub fn preserve_objects_for_their_debuginfo(sess: &Session) -> bool { |
| // If the objects don't have debuginfo there's nothing to preserve. |
| if sess.opts.debuginfo == config::DebugInfo::None { |
| return false |
| } |
| |
| // If we're only producing artifacts that are archives, no need to preserve |
| // the objects as they're losslessly contained inside the archives. |
| let output_linked = sess.crate_types.borrow() |
| .iter() |
| .any(|&x| x != config::CrateType::Rlib && x != config::CrateType::Staticlib); |
| if !output_linked { |
| return false |
| } |
| |
| // If we're on OSX then the equivalent of split dwarf is turned on by |
| // default. The final executable won't actually have any debug information |
| // except it'll have pointers to elsewhere. Historically we've always run |
| // `dsymutil` to "link all the dwarf together" but this is actually sort of |
| // a bummer for incremental compilation! (the whole point of split dwarf is |
| // that you don't do this sort of dwarf link). |
| // |
| // Basically as a result this just means that if we're on OSX and we're |
| // *not* running dsymutil then the object files are the only source of truth |
| // for debug information, so we must preserve them. |
| if sess.target.target.options.is_like_osx { |
| match sess.opts.debugging_opts.run_dsymutil { |
| // dsymutil is not being run, preserve objects |
| Some(false) => return true, |
| |
| // dsymutil is being run, no need to preserve the objects |
| Some(true) => return false, |
| |
| // The default historical behavior was to always run dsymutil, so |
| // we're preserving that temporarily, but we're likely to switch the |
| // default soon. |
| None => return false, |
| } |
| } |
| |
| false |
| } |
| |
| pub fn archive_search_paths(sess: &Session) -> Vec<PathBuf> { |
| sess.target_filesearch(PathKind::Native).search_path_dirs() |
| } |
| |
| enum RlibFlavor { |
| Normal, |
| StaticlibBase, |
| } |
| |
| pub fn print_native_static_libs(sess: &Session, all_native_libs: &[NativeLibrary]) { |
| let lib_args: Vec<_> = all_native_libs.iter() |
| .filter(|l| relevant_lib(sess, l)) |
| .filter_map(|lib| { |
| let name = lib.name?; |
| match lib.kind { |
| NativeLibraryKind::NativeStaticNobundle | |
| NativeLibraryKind::NativeUnknown => { |
| if sess.target.target.options.is_like_msvc { |
| Some(format!("{}.lib", name)) |
| } else { |
| Some(format!("-l{}", name)) |
| } |
| }, |
| NativeLibraryKind::NativeFramework => { |
| // ld-only syntax, since there are no frameworks in MSVC |
| Some(format!("-framework {}", name)) |
| }, |
| // These are included, no need to print them |
| NativeLibraryKind::NativeStatic => None, |
| } |
| }) |
| .collect(); |
| if !lib_args.is_empty() { |
| sess.note_without_error("Link against the following native artifacts when linking \ |
| against this static library. The order and any duplication \ |
| can be significant on some platforms."); |
| // Prefix for greppability |
| sess.note_without_error(&format!("native-static-libs: {}", &lib_args.join(" "))); |
| } |
| } |
| |
| pub fn get_file_path(sess: &Session, name: &str) -> PathBuf { |
| let fs = sess.target_filesearch(PathKind::Native); |
| let file_path = fs.get_lib_path().join(name); |
| if file_path.exists() { |
| return file_path |
| } |
| for search_path in fs.search_paths() { |
| let file_path = search_path.dir.join(name); |
| if file_path.exists() { |
| return file_path |
| } |
| } |
| PathBuf::from(name) |
| } |
| |
| pub fn exec_linker(sess: &Session, cmd: &mut Command, out_filename: &Path, tmpdir: &Path) |
| -> io::Result<Output> |
| { |
| // When attempting to spawn the linker we run a risk of blowing out the |
| // size limits for spawning a new process with respect to the arguments |
| // we pass on the command line. |
| // |
| // Here we attempt to handle errors from the OS saying "your list of |
| // arguments is too big" by reinvoking the linker again with an `@`-file |
| // that contains all the arguments. The theory is that this is then |
| // accepted on all linkers and the linker will read all its options out of |
| // there instead of looking at the command line. |
| if !cmd.very_likely_to_exceed_some_spawn_limit() { |
| match cmd.command().stdout(Stdio::piped()).stderr(Stdio::piped()).spawn() { |
| Ok(child) => { |
| let output = child.wait_with_output(); |
| flush_linked_file(&output, out_filename)?; |
| return output; |
| } |
| Err(ref e) if command_line_too_big(e) => { |
| info!("command line to linker was too big: {}", e); |
| } |
| Err(e) => return Err(e) |
| } |
| } |
| |
| info!("falling back to passing arguments to linker via an @-file"); |
| let mut cmd2 = cmd.clone(); |
| let mut args = String::new(); |
| for arg in cmd2.take_args() { |
| args.push_str(&Escape { |
| arg: arg.to_str().unwrap(), |
| is_like_msvc: sess.target.target.options.is_like_msvc, |
| }.to_string()); |
| args.push_str("\n"); |
| } |
| let file = tmpdir.join("linker-arguments"); |
| let bytes = if sess.target.target.options.is_like_msvc { |
| let mut out = Vec::with_capacity((1 + args.len()) * 2); |
| // start the stream with a UTF-16 BOM |
| for c in std::iter::once(0xFEFF).chain(args.encode_utf16()) { |
| // encode in little endian |
| out.push(c as u8); |
| out.push((c >> 8) as u8); |
| } |
| out |
| } else { |
| args.into_bytes() |
| }; |
| fs::write(&file, &bytes)?; |
| cmd2.arg(format!("@{}", file.display())); |
| info!("invoking linker {:?}", cmd2); |
| let output = cmd2.output(); |
| flush_linked_file(&output, out_filename)?; |
| return output; |
| |
| #[cfg(unix)] |
| fn flush_linked_file(_: &io::Result<Output>, _: &Path) -> io::Result<()> { |
| Ok(()) |
| } |
| |
| #[cfg(windows)] |
| fn flush_linked_file(command_output: &io::Result<Output>, out_filename: &Path) |
| -> io::Result<()> |
| { |
| // On Windows, under high I/O load, output buffers are sometimes not flushed, |
| // even long after process exit, causing nasty, non-reproducible output bugs. |
| // |
| // File::sync_all() calls FlushFileBuffers() down the line, which solves the problem. |
| // |
| // А full writeup of the original Chrome bug can be found at |
| // randomascii.wordpress.com/2018/02/25/compiler-bug-linker-bug-windows-kernel-bug/amp |
| |
| if let &Ok(ref out) = command_output { |
| if out.status.success() { |
| if let Ok(of) = fs::OpenOptions::new().write(true).open(out_filename) { |
| of.sync_all()?; |
| } |
| } |
| } |
| |
| Ok(()) |
| } |
| |
| #[cfg(unix)] |
| fn command_line_too_big(err: &io::Error) -> bool { |
| err.raw_os_error() == Some(::libc::E2BIG) |
| } |
| |
| #[cfg(windows)] |
| fn command_line_too_big(err: &io::Error) -> bool { |
| const ERROR_FILENAME_EXCED_RANGE: i32 = 206; |
| err.raw_os_error() == Some(ERROR_FILENAME_EXCED_RANGE) |
| } |
| |
| struct Escape<'a> { |
| arg: &'a str, |
| is_like_msvc: bool, |
| } |
| |
| impl<'a> fmt::Display for Escape<'a> { |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| if self.is_like_msvc { |
| // This is "documented" at |
| // https://msdn.microsoft.com/en-us/library/4xdcbak7.aspx |
| // |
| // Unfortunately there's not a great specification of the |
| // syntax I could find online (at least) but some local |
| // testing showed that this seemed sufficient-ish to catch |
| // at least a few edge cases. |
| write!(f, "\"")?; |
| for c in self.arg.chars() { |
| match c { |
| '"' => write!(f, "\\{}", c)?, |
| c => write!(f, "{}", c)?, |
| } |
| } |
| write!(f, "\"")?; |
| } else { |
| // This is documented at https://linux.die.net/man/1/ld, namely: |
| // |
| // > Options in file are separated by whitespace. A whitespace |
| // > character may be included in an option by surrounding the |
| // > entire option in either single or double quotes. Any |
| // > character (including a backslash) may be included by |
| // > prefixing the character to be included with a backslash. |
| // |
| // We put an argument on each line, so all we need to do is |
| // ensure the line is interpreted as one whole argument. |
| for c in self.arg.chars() { |
| match c { |
| '\\' | ' ' => write!(f, "\\{}", c)?, |
| c => write!(f, "{}", c)?, |
| } |
| } |
| } |
| Ok(()) |
| } |
| } |
| } |
| |
| fn link_args<'a, B: ArchiveBuilder<'a>>(cmd: &mut dyn Linker, |
| flavor: LinkerFlavor, |
| sess: &'a Session, |
| crate_type: config::CrateType, |
| tmpdir: &Path, |
| out_filename: &Path, |
| codegen_results: &CodegenResults) { |
| |
| // Linker plugins should be specified early in the list of arguments |
| cmd.linker_plugin_lto(); |
| |
| // The default library location, we need this to find the runtime. |
| // The location of crates will be determined as needed. |
| let lib_path = sess.target_filesearch(PathKind::All).get_lib_path(); |
| |
| // target descriptor |
| let t = &sess.target.target; |
| |
| cmd.include_path(&fix_windows_verbatim_for_gcc(&lib_path)); |
| |
| for obj in codegen_results.modules.iter().filter_map(|m| m.object.as_ref()) { |
| cmd.add_object(obj); |
| } |
| cmd.output_filename(out_filename); |
| |
| if crate_type == config::CrateType::Executable && |
| sess.target.target.options.is_like_windows { |
| if let Some(ref s) = codegen_results.windows_subsystem { |
| cmd.subsystem(s); |
| } |
| } |
| |
| // If we're building something like a dynamic library then some platforms |
| // need to make sure that all symbols are exported correctly from the |
| // dynamic library. |
| cmd.export_symbols(tmpdir, crate_type); |
| |
| // When linking a dynamic library, we put the metadata into a section of the |
| // executable. This metadata is in a separate object file from the main |
| // object file, so we link that in here. |
| if crate_type == config::CrateType::Dylib || |
| crate_type == config::CrateType::ProcMacro { |
| let obj = codegen_results.metadata_module |
| .as_ref() |
| .and_then(|m| m.object.as_ref()); |
| if let Some(obj) = obj { |
| cmd.add_object(obj); |
| } |
| } |
| |
| let obj = codegen_results.allocator_module |
| .as_ref() |
| .and_then(|m| m.object.as_ref()); |
| if let Some(obj) = obj { |
| cmd.add_object(obj); |
| } |
| |
| // Try to strip as much out of the generated object by removing unused |
| // sections if possible. See more comments in linker.rs |
| if !sess.opts.cg.link_dead_code { |
| let keep_metadata = crate_type == config::CrateType::Dylib; |
| cmd.gc_sections(keep_metadata); |
| } |
| |
| let used_link_args = &codegen_results.crate_info.link_args; |
| |
| if crate_type == config::CrateType::Executable { |
| let mut position_independent_executable = false; |
| |
| if t.options.position_independent_executables { |
| let empty_vec = Vec::new(); |
| let args = sess.opts.cg.link_args.as_ref().unwrap_or(&empty_vec); |
| let more_args = &sess.opts.cg.link_arg; |
| let mut args = args.iter().chain(more_args.iter()).chain(used_link_args.iter()); |
| |
| if is_pic(sess) && !sess.crt_static() && !args.any(|x| *x == "-static") { |
| position_independent_executable = true; |
| } |
| } |
| |
| if position_independent_executable { |
| cmd.position_independent_executable(); |
| } else { |
| // recent versions of gcc can be configured to generate position |
| // independent executables by default. We have to pass -no-pie to |
| // explicitly turn that off. Not applicable to ld. |
| if sess.target.target.options.linker_is_gnu |
| && flavor != LinkerFlavor::Ld { |
| cmd.no_position_independent_executable(); |
| } |
| } |
| } |
| |
| let relro_level = match sess.opts.debugging_opts.relro_level { |
| Some(level) => level, |
| None => t.options.relro_level, |
| }; |
| match relro_level { |
| RelroLevel::Full => { |
| cmd.full_relro(); |
| }, |
| RelroLevel::Partial => { |
| cmd.partial_relro(); |
| }, |
| RelroLevel::Off => { |
| cmd.no_relro(); |
| }, |
| RelroLevel::None => { |
| }, |
| } |
| |
| // Pass optimization flags down to the linker. |
| cmd.optimize(); |
| |
| // Pass debuginfo flags down to the linker. |
| cmd.debuginfo(); |
| |
| // We want to, by default, prevent the compiler from accidentally leaking in |
| // any system libraries, so we may explicitly ask linkers to not link to any |
| // libraries by default. Note that this does not happen for windows because |
| // windows pulls in some large number of libraries and I couldn't quite |
| // figure out which subset we wanted. |
| // |
| // This is all naturally configurable via the standard methods as well. |
| if !sess.opts.cg.default_linker_libraries.unwrap_or(false) && |
| t.options.no_default_libraries |
| { |
| cmd.no_default_libraries(); |
| } |
| |
| // Take careful note of the ordering of the arguments we pass to the linker |
| // here. Linkers will assume that things on the left depend on things to the |
| // right. Things on the right cannot depend on things on the left. This is |
| // all formally implemented in terms of resolving symbols (libs on the right |
| // resolve unknown symbols of libs on the left, but not vice versa). |
| // |
| // For this reason, we have organized the arguments we pass to the linker as |
| // such: |
| // |
| // 1. The local object that LLVM just generated |
| // 2. Local native libraries |
| // 3. Upstream rust libraries |
| // 4. Upstream native libraries |
| // |
| // The rationale behind this ordering is that those items lower down in the |
| // list can't depend on items higher up in the list. For example nothing can |
| // depend on what we just generated (e.g., that'd be a circular dependency). |
| // Upstream rust libraries are not allowed to depend on our local native |
| // libraries as that would violate the structure of the DAG, in that |
| // scenario they are required to link to them as well in a shared fashion. |
| // |
| // Note that upstream rust libraries may contain native dependencies as |
| // well, but they also can't depend on what we just started to add to the |
| // link line. And finally upstream native libraries can't depend on anything |
| // in this DAG so far because they're only dylibs and dylibs can only depend |
| // on other dylibs (e.g., other native deps). |
| add_local_native_libraries(cmd, sess, codegen_results); |
| add_upstream_rust_crates::<B>(cmd, sess, codegen_results, crate_type, tmpdir); |
| add_upstream_native_libraries(cmd, sess, codegen_results, crate_type); |
| |
| // Tell the linker what we're doing. |
| if crate_type != config::CrateType::Executable { |
| cmd.build_dylib(out_filename); |
| } |
| if crate_type == config::CrateType::Executable && sess.crt_static() { |
| cmd.build_static_executable(); |
| } |
| |
| if sess.opts.cg.profile_generate.enabled() { |
| cmd.pgo_gen(); |
| } |
| |
| // FIXME (#2397): At some point we want to rpath our guesses as to |
| // where extern libraries might live, based on the |
| // addl_lib_search_paths |
| if sess.opts.cg.rpath { |
| let target_triple = sess.opts.target_triple.triple(); |
| let mut get_install_prefix_lib_path = || { |
| let install_prefix = option_env!("CFG_PREFIX").expect("CFG_PREFIX"); |
| let tlib = filesearch::relative_target_lib_path(&sess.sysroot, target_triple); |
| let mut path = PathBuf::from(install_prefix); |
| path.push(&tlib); |
| |
| path |
| }; |
| let mut rpath_config = RPathConfig { |
| used_crates: &codegen_results.crate_info.used_crates_dynamic, |
| out_filename: out_filename.to_path_buf(), |
| has_rpath: sess.target.target.options.has_rpath, |
| is_like_osx: sess.target.target.options.is_like_osx, |
| linker_is_gnu: sess.target.target.options.linker_is_gnu, |
| get_install_prefix_lib_path: &mut get_install_prefix_lib_path, |
| }; |
| cmd.args(&rpath::get_rpath_flags(&mut rpath_config)); |
| } |
| |
| // Finally add all the linker arguments provided on the command line along |
| // with any #[link_args] attributes found inside the crate |
| if let Some(ref args) = sess.opts.cg.link_args { |
| cmd.args(args); |
| } |
| cmd.args(&sess.opts.cg.link_arg); |
| cmd.args(&used_link_args); |
| } |
| |
| // # Native library linking |
| // |
| // User-supplied library search paths (-L on the command line). These are |
| // the same paths used to find Rust crates, so some of them may have been |
| // added already by the previous crate linking code. This only allows them |
| // to be found at compile time so it is still entirely up to outside |
| // forces to make sure that library can be found at runtime. |
| // |
| // Also note that the native libraries linked here are only the ones located |
| // in the current crate. Upstream crates with native library dependencies |
| // may have their native library pulled in above. |
| pub fn add_local_native_libraries(cmd: &mut dyn Linker, |
| sess: &Session, |
| codegen_results: &CodegenResults) { |
| let filesearch = sess.target_filesearch(PathKind::All); |
| for search_path in filesearch.search_paths() { |
| match search_path.kind { |
| PathKind::Framework => { cmd.framework_path(&search_path.dir); } |
| _ => { cmd.include_path(&fix_windows_verbatim_for_gcc(&search_path.dir)); } |
| } |
| } |
| |
| let relevant_libs = codegen_results.crate_info.used_libraries.iter().filter(|l| { |
| relevant_lib(sess, l) |
| }); |
| |
| let search_path = archive_search_paths(sess); |
| for lib in relevant_libs { |
| let name = match lib.name { |
| Some(l) => l, |
| None => continue, |
| }; |
| match lib.kind { |
| NativeLibraryKind::NativeUnknown => cmd.link_dylib(name), |
| NativeLibraryKind::NativeFramework => cmd.link_framework(name), |
| NativeLibraryKind::NativeStaticNobundle => cmd.link_staticlib(name), |
| NativeLibraryKind::NativeStatic => cmd.link_whole_staticlib(name, &search_path) |
| } |
| } |
| } |
| |
| // # Rust Crate linking |
| // |
| // Rust crates are not considered at all when creating an rlib output. All |
| // dependencies will be linked when producing the final output (instead of |
| // the intermediate rlib version) |
| fn add_upstream_rust_crates<'a, B: ArchiveBuilder<'a>>(cmd: &mut dyn Linker, |
| sess: &'a Session, |
| codegen_results: &CodegenResults, |
| crate_type: config::CrateType, |
| tmpdir: &Path) { |
| // All of the heavy lifting has previously been accomplished by the |
| // dependency_format module of the compiler. This is just crawling the |
| // output of that module, adding crates as necessary. |
| // |
| // Linking to a rlib involves just passing it to the linker (the linker |
| // will slurp up the object files inside), and linking to a dynamic library |
| // involves just passing the right -l flag. |
| |
| let formats = sess.dependency_formats.borrow(); |
| let data = formats.get(&crate_type).unwrap(); |
| |
| // Invoke get_used_crates to ensure that we get a topological sorting of |
| // crates. |
| let deps = &codegen_results.crate_info.used_crates_dynamic; |
| |
| // There's a few internal crates in the standard library (aka libcore and |
| // libstd) which actually have a circular dependence upon one another. This |
| // currently arises through "weak lang items" where libcore requires things |
| // like `rust_begin_unwind` but libstd ends up defining it. To get this |
| // circular dependence to work correctly in all situations we'll need to be |
| // sure to correctly apply the `--start-group` and `--end-group` options to |
| // GNU linkers, otherwise if we don't use any other symbol from the standard |
| // library it'll get discarded and the whole application won't link. |
| // |
| // In this loop we're calculating the `group_end`, after which crate to |
| // pass `--end-group` and `group_start`, before which crate to pass |
| // `--start-group`. We currently do this by passing `--end-group` after |
| // the first crate (when iterating backwards) that requires a lang item |
| // defined somewhere else. Once that's set then when we've defined all the |
| // necessary lang items we'll pass `--start-group`. |
| // |
| // Note that this isn't amazing logic for now but it should do the trick |
| // for the current implementation of the standard library. |
| let mut group_end = None; |
| let mut group_start = None; |
| let mut end_with = FxHashSet::default(); |
| let info = &codegen_results.crate_info; |
| for &(cnum, _) in deps.iter().rev() { |
| if let Some(missing) = info.missing_lang_items.get(&cnum) { |
| end_with.extend(missing.iter().cloned()); |
| if end_with.len() > 0 && group_end.is_none() { |
| group_end = Some(cnum); |
| } |
| } |
| end_with.retain(|item| info.lang_item_to_crate.get(item) != Some(&cnum)); |
| if end_with.len() == 0 && group_end.is_some() { |
| group_start = Some(cnum); |
| break |
| } |
| } |
| |
| // If we didn't end up filling in all lang items from upstream crates then |
| // we'll be filling it in with our crate. This probably means we're the |
| // standard library itself, so skip this for now. |
| if group_end.is_some() && group_start.is_none() { |
| group_end = None; |
| } |
| |
| let mut compiler_builtins = None; |
| |
| for &(cnum, _) in deps.iter() { |
| if group_start == Some(cnum) { |
| cmd.group_start(); |
| } |
| |
| // We may not pass all crates through to the linker. Some crates may |
| // appear statically in an existing dylib, meaning we'll pick up all the |
| // symbols from the dylib. |
| let src = &codegen_results.crate_info.used_crate_source[&cnum]; |
| match data[cnum.as_usize() - 1] { |
| _ if codegen_results.crate_info.profiler_runtime == Some(cnum) => { |
| add_static_crate::<B>(cmd, sess, codegen_results, tmpdir, crate_type, cnum); |
| } |
| _ if codegen_results.crate_info.sanitizer_runtime == Some(cnum) => { |
| link_sanitizer_runtime::<B>(cmd, sess, codegen_results, tmpdir, cnum); |
| } |
| // compiler-builtins are always placed last to ensure that they're |
| // linked correctly. |
| _ if codegen_results.crate_info.compiler_builtins == Some(cnum) => { |
| assert!(compiler_builtins.is_none()); |
| compiler_builtins = Some(cnum); |
| } |
| Linkage::NotLinked | |
| Linkage::IncludedFromDylib => {} |
| Linkage::Static => { |
| add_static_crate::<B>(cmd, sess, codegen_results, tmpdir, crate_type, cnum); |
| } |
| Linkage::Dynamic => { |
| add_dynamic_crate(cmd, sess, &src.dylib.as_ref().unwrap().0) |
| } |
| } |
| |
| if group_end == Some(cnum) { |
| cmd.group_end(); |
| } |
| } |
| |
| // compiler-builtins are always placed last to ensure that they're |
| // linked correctly. |
| // We must always link the `compiler_builtins` crate statically. Even if it |
| // was already "included" in a dylib (e.g., `libstd` when `-C prefer-dynamic` |
| // is used) |
| if let Some(cnum) = compiler_builtins { |
| add_static_crate::<B>(cmd, sess, codegen_results, tmpdir, crate_type, cnum); |
| } |
| |
| // Converts a library file-stem into a cc -l argument |
| fn unlib<'a>(config: &config::Config, stem: &'a str) -> &'a str { |
| if stem.starts_with("lib") && !config.target.options.is_like_windows { |
| &stem[3..] |
| } else { |
| stem |
| } |
| } |
| |
| // We must link the sanitizer runtime using -Wl,--whole-archive but since |
| // it's packed in a .rlib, it contains stuff that are not objects that will |
| // make the linker error. So we must remove those bits from the .rlib before |
| // linking it. |
| fn link_sanitizer_runtime<'a, B: ArchiveBuilder<'a>>(cmd: &mut dyn Linker, |
| sess: &'a Session, |
| codegen_results: &CodegenResults, |
| tmpdir: &Path, |
| cnum: CrateNum) { |
| let src = &codegen_results.crate_info.used_crate_source[&cnum]; |
| let cratepath = &src.rlib.as_ref().unwrap().0; |
| |
| if sess.target.target.options.is_like_osx { |
| // On Apple platforms, the sanitizer is always built as a dylib, and |
| // LLVM will link to `@rpath/*.dylib`, so we need to specify an |
| // rpath to the library as well (the rpath should be absolute, see |
| // PR #41352 for details). |
| // |
| // FIXME: Remove this logic into librustc_*san once Cargo supports it |
| let rpath = cratepath.parent().unwrap(); |
| let rpath = rpath.to_str().expect("non-utf8 component in path"); |
| cmd.args(&["-Wl,-rpath".into(), "-Xlinker".into(), rpath.into()]); |
| } |
| |
| let dst = tmpdir.join(cratepath.file_name().unwrap()); |
| let mut archive = <B as ArchiveBuilder>::new(sess, &dst, Some(cratepath)); |
| archive.update_symbols(); |
| |
| for f in archive.src_files() { |
| if f.ends_with(RLIB_BYTECODE_EXTENSION) || f == METADATA_FILENAME { |
| archive.remove_file(&f); |
| } |
| } |
| |
| archive.build(); |
| |
| cmd.link_whole_rlib(&dst); |
| } |
| |
| // Adds the static "rlib" versions of all crates to the command line. |
| // There's a bit of magic which happens here specifically related to LTO and |
| // dynamic libraries. Specifically: |
| // |
| // * For LTO, we remove upstream object files. |
| // * For dylibs we remove metadata and bytecode from upstream rlibs |
| // |
| // When performing LTO, almost(*) all of the bytecode from the upstream |
| // libraries has already been included in our object file output. As a |
| // result we need to remove the object files in the upstream libraries so |
| // the linker doesn't try to include them twice (or whine about duplicate |
| // symbols). We must continue to include the rest of the rlib, however, as |
| // it may contain static native libraries which must be linked in. |
| // |
| // (*) Crates marked with `#![no_builtins]` don't participate in LTO and |
| // their bytecode wasn't included. The object files in those libraries must |
| // still be passed to the linker. |
| // |
| // When making a dynamic library, linkers by default don't include any |
| // object files in an archive if they're not necessary to resolve the link. |
| // We basically want to convert the archive (rlib) to a dylib, though, so we |
| // *do* want everything included in the output, regardless of whether the |
| // linker thinks it's needed or not. As a result we must use the |
| // --whole-archive option (or the platform equivalent). When using this |
| // option the linker will fail if there are non-objects in the archive (such |
| // as our own metadata and/or bytecode). All in all, for rlibs to be |
| // entirely included in dylibs, we need to remove all non-object files. |
| // |
| // Note, however, that if we're not doing LTO or we're not producing a dylib |
| // (aka we're making an executable), we can just pass the rlib blindly to |
| // the linker (fast) because it's fine if it's not actually included as |
| // we're at the end of the dependency chain. |
| fn add_static_crate<'a, B: ArchiveBuilder<'a>>(cmd: &mut dyn Linker, |
| sess: &'a Session, |
| codegen_results: &CodegenResults, |
| tmpdir: &Path, |
| crate_type: config::CrateType, |
| cnum: CrateNum) { |
| let src = &codegen_results.crate_info.used_crate_source[&cnum]; |
| let cratepath = &src.rlib.as_ref().unwrap().0; |
| |
| // See the comment above in `link_staticlib` and `link_rlib` for why if |
| // there's a static library that's not relevant we skip all object |
| // files. |
| let native_libs = &codegen_results.crate_info.native_libraries[&cnum]; |
| let skip_native = native_libs.iter().any(|lib| { |
| lib.kind == NativeLibraryKind::NativeStatic && !relevant_lib(sess, lib) |
| }); |
| |
| if (!are_upstream_rust_objects_already_included(sess) || |
| ignored_for_lto(sess, &codegen_results.crate_info, cnum)) && |
| crate_type != config::CrateType::Dylib && |
| !skip_native { |
| cmd.link_rlib(&fix_windows_verbatim_for_gcc(cratepath)); |
| return |
| } |
| |
| let dst = tmpdir.join(cratepath.file_name().unwrap()); |
| let name = cratepath.file_name().unwrap().to_str().unwrap(); |
| let name = &name[3..name.len() - 5]; // chop off lib/.rlib |
| |
| time_ext(sess.time_extended(), Some(sess), &format!("altering {}.rlib", name), || { |
| let mut archive = <B as ArchiveBuilder>::new(sess, &dst, Some(cratepath)); |
| archive.update_symbols(); |
| |
| let mut any_objects = false; |
| for f in archive.src_files() { |
| if f.ends_with(RLIB_BYTECODE_EXTENSION) || f == METADATA_FILENAME { |
| archive.remove_file(&f); |
| continue |
| } |
| |
| let canonical = f.replace("-", "_"); |
| let canonical_name = name.replace("-", "_"); |
| |
| // Look for `.rcgu.o` at the end of the filename to conclude |
| // that this is a Rust-related object file. |
| fn looks_like_rust(s: &str) -> bool { |
| let path = Path::new(s); |
| let ext = path.extension().and_then(|s| s.to_str()); |
| if ext != Some(OutputType::Object.extension()) { |
| return false |
| } |
| let ext2 = path.file_stem() |
| .and_then(|s| Path::new(s).extension()) |
| .and_then(|s| s.to_str()); |
| ext2 == Some(RUST_CGU_EXT) |
| } |
| |
| let is_rust_object = |
| canonical.starts_with(&canonical_name) && |
| looks_like_rust(&f); |
| |
| // If we've been requested to skip all native object files |
| // (those not generated by the rust compiler) then we can skip |
| // this file. See above for why we may want to do this. |
| let skip_because_cfg_say_so = skip_native && !is_rust_object; |
| |
| // If we're performing LTO and this is a rust-generated object |
| // file, then we don't need the object file as it's part of the |
| // LTO module. Note that `#![no_builtins]` is excluded from LTO, |
| // though, so we let that object file slide. |
| let skip_because_lto = are_upstream_rust_objects_already_included(sess) && |
| is_rust_object && |
| (sess.target.target.options.no_builtins || |
| !codegen_results.crate_info.is_no_builtins.contains(&cnum)); |
| |
| if skip_because_cfg_say_so || skip_because_lto { |
| archive.remove_file(&f); |
| } else { |
| any_objects = true; |
| } |
| } |
| |
| if !any_objects { |
| return |
| } |
| archive.build(); |
| |
| // If we're creating a dylib, then we need to include the |
| // whole of each object in our archive into that artifact. This is |
| // because a `dylib` can be reused as an intermediate artifact. |
| // |
| // Note, though, that we don't want to include the whole of a |
| // compiler-builtins crate (e.g., compiler-rt) because it'll get |
| // repeatedly linked anyway. |
| if crate_type == config::CrateType::Dylib && |
| codegen_results.crate_info.compiler_builtins != Some(cnum) { |
| cmd.link_whole_rlib(&fix_windows_verbatim_for_gcc(&dst)); |
| } else { |
| cmd.link_rlib(&fix_windows_verbatim_for_gcc(&dst)); |
| } |
| }); |
| } |
| |
| // Same thing as above, but for dynamic crates instead of static crates. |
| fn add_dynamic_crate(cmd: &mut dyn Linker, sess: &Session, cratepath: &Path) { |
| // Just need to tell the linker about where the library lives and |
| // what its name is |
| let parent = cratepath.parent(); |
| if let Some(dir) = parent { |
| cmd.include_path(&fix_windows_verbatim_for_gcc(dir)); |
| } |
| let filestem = cratepath.file_stem().unwrap().to_str().unwrap(); |
| cmd.link_rust_dylib(Symbol::intern(&unlib(&sess.target, filestem)), |
| parent.unwrap_or(Path::new(""))); |
| } |
| } |
| |
| // Link in all of our upstream crates' native dependencies. Remember that |
| // all of these upstream native dependencies are all non-static |
| // dependencies. We've got two cases then: |
| // |
| // 1. The upstream crate is an rlib. In this case we *must* link in the |
| // native dependency because the rlib is just an archive. |
| // |
| // 2. The upstream crate is a dylib. In order to use the dylib, we have to |
| // have the dependency present on the system somewhere. Thus, we don't |
| // gain a whole lot from not linking in the dynamic dependency to this |
| // crate as well. |
| // |
| // The use case for this is a little subtle. In theory the native |
| // dependencies of a crate are purely an implementation detail of the crate |
| // itself, but the problem arises with generic and inlined functions. If a |
| // generic function calls a native function, then the generic function must |
| // be instantiated in the target crate, meaning that the native symbol must |
| // also be resolved in the target crate. |
| pub fn add_upstream_native_libraries(cmd: &mut dyn Linker, |
| sess: &Session, |
| codegen_results: &CodegenResults, |
| crate_type: config::CrateType) { |
| // Be sure to use a topological sorting of crates because there may be |
| // interdependencies between native libraries. When passing -nodefaultlibs, |
| // for example, almost all native libraries depend on libc, so we have to |
| // make sure that's all the way at the right (liblibc is near the base of |
| // the dependency chain). |
| // |
| // This passes RequireStatic, but the actual requirement doesn't matter, |
| // we're just getting an ordering of crate numbers, we're not worried about |
| // the paths. |
| let formats = sess.dependency_formats.borrow(); |
| let data = formats.get(&crate_type).unwrap(); |
| |
| let crates = &codegen_results.crate_info.used_crates_static; |
| for &(cnum, _) in crates { |
| for lib in codegen_results.crate_info.native_libraries[&cnum].iter() { |
| let name = match lib.name { |
| Some(l) => l, |
| None => continue, |
| }; |
| if !relevant_lib(sess, &lib) { |
| continue |
| } |
| match lib.kind { |
| NativeLibraryKind::NativeUnknown => cmd.link_dylib(name), |
| NativeLibraryKind::NativeFramework => cmd.link_framework(name), |
| NativeLibraryKind::NativeStaticNobundle => { |
| // Link "static-nobundle" native libs only if the crate they originate from |
| // is being linked statically to the current crate. If it's linked dynamically |
| // or is an rlib already included via some other dylib crate, the symbols from |
| // native libs will have already been included in that dylib. |
| if data[cnum.as_usize() - 1] == Linkage::Static { |
| cmd.link_staticlib(name) |
| } |
| }, |
| // ignore statically included native libraries here as we've |
| // already included them when we included the rust library |
| // previously |
| NativeLibraryKind::NativeStatic => {} |
| } |
| } |
| } |
| } |
| |
| pub fn relevant_lib(sess: &Session, lib: &NativeLibrary) -> bool { |
| match lib.cfg { |
| Some(ref cfg) => syntax::attr::cfg_matches(cfg, &sess.parse_sess, None), |
| None => true, |
| } |
| } |
| |
| pub fn are_upstream_rust_objects_already_included(sess: &Session) -> bool { |
| match sess.lto() { |
| config::Lto::Fat => true, |
| config::Lto::Thin => { |
| // If we defer LTO to the linker, we haven't run LTO ourselves, so |
| // any upstream object files have not been copied yet. |
| !sess.opts.cg.linker_plugin_lto.enabled() |
| } |
| config::Lto::No | |
| config::Lto::ThinLocal => false, |
| } |
| } |
| |
| fn is_pic(sess: &Session) -> bool { |
| let reloc_model_arg = match sess.opts.cg.relocation_model { |
| Some(ref s) => &s[..], |
| None => &sess.target.target.options.relocation_model[..], |
| }; |
| |
| reloc_model_arg == "pic" |
| } |
