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Diffstat (limited to 'src/librustc_codegen_llvm/back/linker.rs')
| -rw-r--r-- | src/librustc_codegen_llvm/back/linker.rs | 1095 |
1 files changed, 0 insertions, 1095 deletions
diff --git a/src/librustc_codegen_llvm/back/linker.rs b/src/librustc_codegen_llvm/back/linker.rs deleted file mode 100644 index e18c8b9dec4..00000000000 --- a/src/librustc_codegen_llvm/back/linker.rs +++ /dev/null @@ -1,1095 +0,0 @@ -// Copyright 2015 The Rust Project Developers. See the COPYRIGHT -// file at the top-level directory of this distribution and at -// http://rust-lang.org/COPYRIGHT. -// -// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or -// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license -// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your -// option. This file may not be copied, modified, or distributed -// except according to those terms. - -use rustc_data_structures::fx::FxHashMap; -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 back::archive; -use back::command::Command; -use back::symbol_export; -use rustc::hir::def_id::{LOCAL_CRATE, CrateNum}; -use rustc::middle::dependency_format::Linkage; -use rustc::session::Session; -use rustc::session::config::{self, CrateType, OptLevel, DebugInfo, - CrossLangLto}; -use rustc::ty::TyCtxt; -use rustc_target::spec::{LinkerFlavor, LldFlavor}; -use serialize::{json, Encoder}; -use llvm_util; - -/// For all the linkers we support, and information they might -/// need out of the shared crate context before we get rid of it. -pub struct LinkerInfo { - exports: FxHashMap<CrateType, Vec<String>>, -} - -impl LinkerInfo { - pub fn new(tcx: TyCtxt) -> LinkerInfo { - LinkerInfo { - exports: tcx.sess.crate_types.borrow().iter().map(|&c| { - (c, exported_symbols(tcx, c)) - }).collect(), - } - } - - pub fn to_linker<'a>(&'a self, - cmd: Command, - sess: &'a Session, - flavor: LinkerFlavor) -> Box<dyn Linker+'a> { - match flavor { - LinkerFlavor::Lld(LldFlavor::Link) | - LinkerFlavor::Msvc => { - Box::new(MsvcLinker { - cmd, - sess, - info: self - }) as Box<dyn Linker> - } - LinkerFlavor::Em => { - Box::new(EmLinker { - cmd, - sess, - info: self - }) as Box<dyn Linker> - } - LinkerFlavor::Gcc => { - Box::new(GccLinker { - cmd, - sess, - info: self, - hinted_static: false, - is_ld: false, - }) as Box<dyn Linker> - } - - LinkerFlavor::Lld(LldFlavor::Ld) | - LinkerFlavor::Lld(LldFlavor::Ld64) | - LinkerFlavor::Ld => { - Box::new(GccLinker { - cmd, - sess, - info: self, - hinted_static: false, - is_ld: true, - }) as Box<dyn Linker> - } - - LinkerFlavor::Lld(LldFlavor::Wasm) => { - Box::new(WasmLd { - cmd, - sess, - info: self - }) 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 link_dylib(&mut self, lib: &str); - fn link_rust_dylib(&mut self, lib: &str, path: &Path); - fn link_framework(&mut self, framework: &str); - fn link_staticlib(&mut self, lib: &str); - fn link_rlib(&mut self, lib: &Path); - fn link_whole_rlib(&mut self, lib: &Path); - fn link_whole_staticlib(&mut self, lib: &str, 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 position_independent_executable(&mut self); - fn no_position_independent_executable(&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 debuginfo(&mut self); - fn no_default_libraries(&mut self); - fn build_dylib(&mut self, out_filename: &Path); - fn build_static_executable(&mut self); - fn args(&mut self, args: &[String]); - fn export_symbols(&mut self, tmpdir: &Path, crate_type: CrateType); - fn subsystem(&mut self, subsystem: &str); - fn group_start(&mut self); - fn group_end(&mut self); - fn cross_lang_lto(&mut self); - // Should have been finalize(self), but we don't support self-by-value on trait objects (yet?). - fn finalize(&mut self) -> Command; -} - -pub struct GccLinker<'a> { - cmd: Command, - sess: &'a Session, - info: &'a LinkerInfo, - hinted_static: bool, // Keeps track of the current hinting mode. - // Link as ld - is_ld: bool, -} - -impl<'a> GccLinker<'a> { - /// Argument that must be passed *directly* to the linker - /// - /// These arguments need to be prepended with '-Wl,' when a gcc-style linker is used - fn linker_arg<S>(&mut self, arg: S) -> &mut Self - where S: AsRef<OsStr> - { - if !self.is_ld { - let mut os = OsString::from("-Wl,"); - os.push(arg.as_ref()); - self.cmd.arg(os); - } else { - self.cmd.arg(arg); - } - self - } - - fn takes_hints(&self) -> bool { - !self.sess.target.target.options.is_like_osx - } - - // 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_cross_lang_lto_args(&mut self, plugin_path: Option<&OsStr>) { - if let Some(plugin_path) = plugin_path { - let mut arg = OsString::from("-plugin="); - arg.push(plugin_path); - self.linker_arg(&arg); - } - - let opt_level = match self.sess.opts.optimize { - config::OptLevel::No => "O0", - config::OptLevel::Less => "O1", - config::OptLevel::Default => "O2", - config::OptLevel::Aggressive => "O3", - config::OptLevel::Size => "Os", - config::OptLevel::SizeMin => "Oz", - }; - - self.linker_arg(&format!("-plugin-opt={}", opt_level)); - self.linker_arg(&format!("-plugin-opt=mcpu={}", llvm_util::target_cpu(self.sess))); - - match self.sess.lto() { - config::Lto::Thin | - config::Lto::ThinLocal => { - self.linker_arg("-plugin-opt=thin"); - } - config::Lto::Fat | - config::Lto::No => { - // default to regular LTO - } - } - } -} - -impl<'a> Linker for GccLinker<'a> { - fn link_dylib(&mut self, lib: &str) { self.hint_dynamic(); self.cmd.arg(format!("-l{}",lib)); } - fn link_staticlib(&mut self, lib: &str) { - self.hint_static(); self.cmd.arg(format!("-l{}",lib)); - } - fn link_rlib(&mut self, lib: &Path) { self.hint_static(); self.cmd.arg(lib); } - fn include_path(&mut self, path: &Path) { self.cmd.arg("-L").arg(path); } - fn framework_path(&mut self, path: &Path) { self.cmd.arg("-F").arg(path); } - fn output_filename(&mut self, path: &Path) { self.cmd.arg("-o").arg(path); } - fn add_object(&mut self, path: &Path) { self.cmd.arg(path); } - fn position_independent_executable(&mut self) { self.cmd.arg("-pie"); } - fn no_position_independent_executable(&mut self) { self.cmd.arg("-no-pie"); } - fn full_relro(&mut self) { self.linker_arg("-zrelro"); self.linker_arg("-znow"); } - fn partial_relro(&mut self) { self.linker_arg("-zrelro"); } - fn no_relro(&mut self) { self.linker_arg("-znorelro"); } - fn build_static_executable(&mut self) { self.cmd.arg("-static"); } - fn args(&mut self, args: &[String]) { self.cmd.args(args); } - - 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) { - self.hint_dynamic(); - 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, search_path: &[PathBuf]) { - self.hint_static(); - let target = &self.sess.target.target; - if !target.options.is_like_osx { - self.linker_arg("--whole-archive").cmd.arg(format!("-l{}",lib)); - self.linker_arg("--no-whole-archive"); - } else { - // -force_load is the macOS equivalent of --whole-archive, but it - // involves passing the full path to the library to link. - self.linker_arg("-force_load"); - let lib = archive::find_library(lib, search_path, &self.sess); - self.linker_arg(&lib); - } - } - - fn link_whole_rlib(&mut self, lib: &Path) { - self.hint_static(); - if self.sess.target.target.options.is_like_osx { - self.linker_arg("-force_load"); - self.linker_arg(&lib); - } else { - self.linker_arg("--whole-archive").cmd.arg(lib); - self.linker_arg("--no-whole-archive"); - } - } - - fn gc_sections(&mut self, keep_metadata: bool) { - // The dead_strip option to the linker specifies that functions and data - // unreachable by the entry point will be removed. This is quite useful - // with Rust's compilation model of compiling libraries at a time into - // one object file. For example, this brings hello world from 1.7MB to - // 458K. - // - // Note that this is done for both executables and dynamic libraries. We - // won't get much benefit from dylibs because LLVM will have already - // stripped away as much as it could. This has not been seen to impact - // link times negatively. - // - // -dead_strip can't be part of the pre_link_args because it's also used - // for partial linking when using multiple codegen units (-r). So we - // insert it here. - if self.sess.target.target.options.is_like_osx { - self.linker_arg("-dead_strip"); - } else if self.sess.target.target.options.is_like_solaris { - self.linker_arg("-zignore"); - - // If we're building a dylib, we don't use --gc-sections because LLVM - // has already done the best it can do, and we also don't want to - // eliminate the metadata. If we're building an executable, however, - // --gc-sections drops the size of hello world from 1.8MB to 597K, a 67% - // reduction. - } else if !keep_metadata { - self.linker_arg("--gc-sections"); - } - } - - fn optimize(&mut self) { - if !self.sess.target.target.options.linker_is_gnu { return } - - // GNU-style linkers support optimization with -O. GNU ld doesn't - // need a numeric argument, but other linkers do. - if self.sess.opts.optimize == config::OptLevel::Default || - self.sess.opts.optimize == config::OptLevel::Aggressive { - self.linker_arg("-O1"); - } - } - - fn pgo_gen(&mut self) { - if !self.sess.target.target.options.linker_is_gnu { return } - - // If we're doing PGO generation stuff and on a GNU-like linker, use the - // "-u" flag to properly pull in the profiler runtime bits. - // - // This is because LLVM otherwise won't add the needed initialization - // for us on Linux (though the extra flag should be harmless if it - // does). - // - // See https://reviews.llvm.org/D14033 and https://reviews.llvm.org/D14030. - // - // Though it may be worth to try to revert those changes upstream, since - // the overhead of the initialization should be minor. - self.cmd.arg("-u"); - self.cmd.arg("__llvm_profile_runtime"); - } - - fn debuginfo(&mut self) { - match self.sess.opts.debuginfo { - DebugInfo::None => { - // If we are building without debuginfo enabled and we were called with - // `-Zstrip-debuginfo-if-disabled=yes`, tell the linker to strip any debuginfo - // found when linking to get rid of symbols from libstd. - match self.sess.opts.debugging_opts.strip_debuginfo_if_disabled { - Some(true) => { self.linker_arg("-S"); }, - _ => {}, - } - }, - _ => {}, - }; - } - - fn no_default_libraries(&mut self) { - if !self.is_ld { - self.cmd.arg("-nodefaultlibs"); - } - } - - fn build_dylib(&mut self, out_filename: &Path) { - // On mac we need to tell the linker to let this library be rpathed - if self.sess.target.target.options.is_like_osx { - self.cmd.arg("-dynamiclib"); - self.linker_arg("-dylib"); - - // Note that the `osx_rpath_install_name` option here is a hack - // purely to support rustbuild right now, we should get a more - // principled solution at some point to force the compiler to pass - // the right `-Wl,-install_name` with an `@rpath` in it. - if self.sess.opts.cg.rpath || - self.sess.opts.debugging_opts.osx_rpath_install_name { - self.linker_arg("-install_name"); - let mut v = OsString::from("@rpath/"); - v.push(out_filename.file_name().unwrap()); - self.linker_arg(&v); - } - } else { - self.cmd.arg("-shared"); - } - } - - fn export_symbols(&mut self, tmpdir: &Path, crate_type: CrateType) { - // If we're compiling a dylib, then we let symbol visibility in object - // files to take care of whether they're exported or not. - // - // If we're compiling a cdylib, however, 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 crate_type == CrateType::Dylib || - crate_type == CrateType::ProcMacro { - return - } - - let mut arg = OsString::new(); - let path = tmpdir.join("list"); - - debug!("EXPORTED SYMBOLS:"); - - if self.sess.target.target.options.is_like_osx { - // Write a plain, newline-separated list of symbols - let res = (|| -> io::Result<()> { - let mut f = BufWriter::new(File::create(&path)?); - for sym in self.info.exports[&crate_type].iter() { - debug!(" _{}", sym); - writeln!(f, "_{}", sym)?; - } - Ok(()) - })(); - if let Err(e) = res { - self.sess.fatal(&format!("failed to write lib.def file: {}", e)); - } - } else { - // Write an LD version script - let res = (|| -> io::Result<()> { - let mut f = BufWriter::new(File::create(&path)?); - writeln!(f, "{{\n global:")?; - for sym in self.info.exports[&crate_type].iter() { - debug!(" {};", sym); - writeln!(f, " {};", sym)?; - } - writeln!(f, "\n local:\n *;\n}};")?; - Ok(()) - })(); - if let Err(e) = res { - self.sess.fatal(&format!("failed to write version script: {}", e)); - } - } - - if self.sess.target.target.options.is_like_osx { - if !self.is_ld { - arg.push("-Wl,") - } - arg.push("-exported_symbols_list,"); - } else if self.sess.target.target.options.is_like_solaris { - if !self.is_ld { - arg.push("-Wl,") - } - arg.push("-M,"); - } else { - if !self.is_ld { - arg.push("-Wl,") - } - arg.push("--version-script="); - } - - arg.push(&path); - self.cmd.arg(arg); - } - - fn subsystem(&mut self, subsystem: &str) { - self.linker_arg("--subsystem"); - self.linker_arg(&subsystem); - } - - fn finalize(&mut self) -> Command { - self.hint_dynamic(); // Reset to default before returning the composed command line. - let mut cmd = Command::new(""); - ::std::mem::swap(&mut cmd, &mut self.cmd); - cmd - } - - fn group_start(&mut self) { - if !self.sess.target.target.options.is_like_osx { - self.linker_arg("--start-group"); - } - } - - fn group_end(&mut self) { - if !self.sess.target.target.options.is_like_osx { - self.linker_arg("--end-group"); - } - } - - fn cross_lang_lto(&mut self) { - match self.sess.opts.debugging_opts.cross_lang_lto { - CrossLangLto::Disabled => { - // Nothing to do - } - CrossLangLto::LinkerPluginAuto => { - self.push_cross_lang_lto_args(None); - } - CrossLangLto::LinkerPlugin(ref path) => { - self.push_cross_lang_lto_args(Some(path.as_os_str())); - } - } - } -} - -pub struct MsvcLinker<'a> { - cmd: Command, - sess: &'a Session, - info: &'a LinkerInfo -} - -impl<'a> Linker for MsvcLinker<'a> { - fn link_rlib(&mut self, lib: &Path) { self.cmd.arg(lib); } - fn add_object(&mut self, path: &Path) { self.cmd.arg(path); } - fn args(&mut self, args: &[String]) { self.cmd.args(args); } - - fn build_dylib(&mut self, out_filename: &Path) { - self.cmd.arg("/DLL"); - let mut arg: OsString = "/IMPLIB:".into(); - arg.push(out_filename.with_extension("dll.lib")); - self.cmd.arg(arg); - } - - fn build_static_executable(&mut self) { - // noop - } - - fn gc_sections(&mut self, _keep_metadata: bool) { - // MSVC's ICF (Identical COMDAT Folding) link optimization is - // slow for Rust and thus we disable it by default when not in - // optimization build. - if self.sess.opts.optimize != config::OptLevel::No { - self.cmd.arg("/OPT:REF,ICF"); - } else { - // It is necessary to specify NOICF here, because /OPT:REF - // implies ICF by default. - self.cmd.arg("/OPT:REF,NOICF"); - } - } - - fn link_dylib(&mut self, lib: &str) { - self.cmd.arg(&format!("{}.lib", 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 fs::metadata(&path.join(&name)).is_ok() { - self.cmd.arg(name); - } - } - - fn link_staticlib(&mut self, lib: &str) { - self.cmd.arg(&format!("{}.lib", lib)); - } - - fn position_independent_executable(&mut self) { - // noop - } - - fn no_position_independent_executable(&mut self) { - // noop - } - - fn full_relro(&mut self) { - // noop - } - - fn partial_relro(&mut self) { - // noop - } - - fn no_relro(&mut self) { - // noop - } - - fn no_default_libraries(&mut self) { - // Currently we don't pass the /NODEFAULTLIB flag to the linker on MSVC - // as there's been trouble in the past of linking the C++ standard - // library required by LLVM. This likely needs to happen one day, but - // in general Windows is also a more controlled environment than - // Unix, so it's not necessarily as critical that this be implemented. - // - // Note that there are also some licensing worries about statically - // linking some libraries which require a specific agreement, so it may - // not ever be possible for us to pass this flag. - } - - 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) { - bug!("frameworks are not supported on windows") - } - - fn link_whole_staticlib(&mut self, lib: &str, _search_path: &[PathBuf]) { - // not supported? - self.link_staticlib(lib); - } - fn link_whole_rlib(&mut self, path: &Path) { - // not supported? - self.link_rlib(path); - } - fn optimize(&mut self) { - // Needs more investigation of `/OPT` arguments - } - - fn pgo_gen(&mut self) { - // Nothing needed here. - } - - fn debuginfo(&mut self) { - // 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 the PDB file - let sysroot = self.sess.sysroot(); - let natvis_dir_path = sysroot.join("lib\\rustlib\\etc"); - if let Ok(natvis_dir) = fs::read_dir(&natvis_dir_path) { - // LLVM 5.0.0's lld-link frontend doesn't yet recognize, and chokes - // on, the /NATVIS:... flags. LLVM 6 (or earlier) should at worst ignore - // them, eventually mooting this workaround, per this landed patch: - // https://github.com/llvm-mirror/lld/commit/27b9c4285364d8d76bb43839daa100 - if let Some(ref linker_path) = self.sess.opts.cg.linker { - if let Some(linker_name) = Path::new(&linker_path).file_stem() { - if linker_name.to_str().unwrap().to_lowercase() == "lld-link" { - self.sess.warn("not embedding natvis: lld-link may not support the flag"); - return; - } - } - } - 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)); - }, - } - } - } - } - - // 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) { - let path = tmpdir.join("lib.def"); - let res = (|| -> io::Result<()> { - let mut f = BufWriter::new(File::create(&path)?); - - // Start off with the standard module name header and then go - // straight to exports. - writeln!(f, "LIBRARY")?; - writeln!(f, "EXPORTS")?; - for symbol in self.info.exports[&crate_type].iter() { - debug!(" _{}", symbol); - writeln!(f, " {}", symbol)?; - } - Ok(()) - })(); - if let Err(e) = res { - self.sess.fatal(&format!("failed to write lib.def file: {}", e)); - } - let mut arg = OsString::from("/DEF:"); - arg.push(path); - self.cmd.arg(&arg); - } - - fn subsystem(&mut self, subsystem: &str) { - // Note that previous passes of the compiler validated this subsystem, - // so we just blindly pass it to the linker. - self.cmd.arg(&format!("/SUBSYSTEM:{}", subsystem)); - - // Windows has two subsystems we're interested in right now, the console - // and windows subsystems. These both implicitly have different entry - // points (starting symbols). The console entry point starts with - // `mainCRTStartup` and the windows entry point starts with - // `WinMainCRTStartup`. These entry points, defined in system libraries, - // will then later probe for either `main` or `WinMain`, respectively to - // start the application. - // - // In Rust we just always generate a `main` function so we want control - // to always start there, so we force the entry point on the windows - // subsystem to be `mainCRTStartup` to get everything booted up - // correctly. - // - // For more information see RFC #1665 - if subsystem == "windows" { - self.cmd.arg("/ENTRY:mainCRTStartup"); - } - } - - fn finalize(&mut self) -> Command { - let mut cmd = Command::new(""); - ::std::mem::swap(&mut cmd, &mut self.cmd); - cmd - } - - // MSVC doesn't need group indicators - fn group_start(&mut self) {} - fn group_end(&mut self) {} - - fn cross_lang_lto(&mut self) { - // Do nothing - } -} - -pub struct EmLinker<'a> { - cmd: Command, - sess: &'a Session, - info: &'a LinkerInfo -} - -impl<'a> Linker for EmLinker<'a> { - fn include_path(&mut self, path: &Path) { - self.cmd.arg("-L").arg(path); - } - - fn link_staticlib(&mut self, lib: &str) { - 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) { - // Emscripten always links statically - self.link_staticlib(lib); - } - - fn link_whole_staticlib(&mut self, lib: &str, _search_path: &[PathBuf]) { - // not supported? - self.link_staticlib(lib); - } - - fn link_whole_rlib(&mut self, lib: &Path) { - // not supported? - self.link_rlib(lib); - } - - fn link_rust_dylib(&mut self, lib: &str, _path: &Path) { - self.link_dylib(lib); - } - - fn link_rlib(&mut self, lib: &Path) { - self.add_object(lib); - } - - fn position_independent_executable(&mut self) { - // noop - } - - fn no_position_independent_executable(&mut self) { - // noop - } - - fn full_relro(&mut self) { - // noop - } - - fn partial_relro(&mut self) { - // noop - } - - fn no_relro(&mut self) { - // noop - } - - fn args(&mut self, args: &[String]) { - self.cmd.args(args); - } - - fn framework_path(&mut self, _path: &Path) { - bug!("frameworks are not supported on Emscripten") - } - - fn link_framework(&mut self, _framework: &str) { - bug!("frameworks are not supported on Emscripten") - } - - fn gc_sections(&mut self, _keep_metadata: bool) { - // noop - } - - fn optimize(&mut self) { - // Emscripten performs own optimizations - self.cmd.arg(match self.sess.opts.optimize { - OptLevel::No => "-O0", - OptLevel::Less => "-O1", - OptLevel::Default => "-O2", - OptLevel::Aggressive => "-O3", - OptLevel::Size => "-Os", - OptLevel::SizeMin => "-Oz" - }); - // Unusable until https://github.com/rust-lang/rust/issues/38454 is resolved - self.cmd.args(&["--memory-init-file", "0"]); - } - - fn pgo_gen(&mut self) { - // noop, but maybe we need something like the gnu linker? - } - - fn debuginfo(&mut self) { - // Preserve names or generate source maps depending on debug info - self.cmd.arg(match self.sess.opts.debuginfo { - DebugInfo::None => "-g0", - DebugInfo::Limited => "-g3", - DebugInfo::Full => "-g4" - }); - } - - fn no_default_libraries(&mut self) { - self.cmd.args(&["-s", "DEFAULT_LIBRARY_FUNCS_TO_INCLUDE=[]"]); - } - - fn build_dylib(&mut self, _out_filename: &Path) { - bug!("building dynamic library is unsupported on Emscripten") - } - - fn build_static_executable(&mut self) { - // noop - } - - fn export_symbols(&mut self, _tmpdir: &Path, crate_type: CrateType) { - let symbols = &self.info.exports[&crate_type]; - - debug!("EXPORTED SYMBOLS:"); - - self.cmd.arg("-s"); - - let mut arg = OsString::from("EXPORTED_FUNCTIONS="); - let mut encoded = String::new(); - - { - let mut encoder = json::Encoder::new(&mut encoded); - let res = encoder.emit_seq(symbols.len(), |encoder| { - for (i, sym) in symbols.iter().enumerate() { - encoder.emit_seq_elt(i, |encoder| { - encoder.emit_str(&("_".to_string() + sym)) - })?; - } - Ok(()) - }); - if let Err(e) = res { - self.sess.fatal(&format!("failed to encode exported symbols: {}", e)); - } - } - debug!("{}", encoded); - arg.push(encoded); - - self.cmd.arg(arg); - } - - fn subsystem(&mut self, _subsystem: &str) { - // noop - } - - fn finalize(&mut self) -> Command { - let mut cmd = Command::new(""); - ::std::mem::swap(&mut cmd, &mut self.cmd); - cmd - } - - // Appears not necessary on Emscripten - fn group_start(&mut self) {} - fn group_end(&mut self) {} - - fn cross_lang_lto(&mut self) { - // Do nothing - } -} - -fn exported_symbols(tcx: TyCtxt, crate_type: CrateType) -> Vec<String> { - let mut symbols = Vec::new(); - - let export_threshold = symbol_export::crates_export_threshold(&[crate_type]); - for &(symbol, level) in tcx.exported_symbols(LOCAL_CRATE).iter() { - if level.is_below_threshold(export_threshold) { - symbols.push(symbol.symbol_name(tcx).to_string()); - } - } - - let formats = tcx.sess.dependency_formats.borrow(); - let deps = formats[&crate_type].iter(); - - for (index, dep_format) in deps.enumerate() { - let cnum = CrateNum::new(index + 1); - // For each dependency that we are linking to statically ... - if *dep_format == Linkage::Static { - // ... we add its symbol list to our export list. - for &(symbol, level) in tcx.exported_symbols(cnum).iter() { - if level.is_below_threshold(export_threshold) { - symbols.push(symbol.symbol_name(tcx).to_string()); - } - } - } - } - - symbols -} - -pub struct WasmLd<'a> { - cmd: Command, - sess: &'a Session, - info: &'a LinkerInfo, -} - -impl<'a> Linker for WasmLd<'a> { - fn link_dylib(&mut self, lib: &str) { - self.cmd.arg("-l").arg(lib); - } - - fn link_staticlib(&mut self, lib: &str) { - 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 position_independent_executable(&mut self) { - } - - fn full_relro(&mut self) { - } - - fn partial_relro(&mut self) { - } - - fn no_relro(&mut self) { - } - - fn build_static_executable(&mut self) { - } - - fn args(&mut self, args: &[String]) { - self.cmd.args(args); - } - - fn link_rust_dylib(&mut self, lib: &str, _path: &Path) { - self.cmd.arg("-l").arg(lib); - } - - fn link_framework(&mut self, _framework: &str) { - panic!("frameworks not supported") - } - - fn link_whole_staticlib(&mut self, lib: &str, _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 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) { - } - - fn no_default_libraries(&mut self) { - } - - fn build_dylib(&mut self, _out_filename: &Path) { - } - - fn export_symbols(&mut self, _tmpdir: &Path, crate_type: CrateType) { - for sym in self.info.exports[&crate_type].iter() { - self.cmd.arg("--export").arg(&sym); - } - } - - fn subsystem(&mut self, _subsystem: &str) { - } - - fn no_position_independent_executable(&mut self) { - } - - fn finalize(&mut self) -> Command { - // There have been reports in the wild (rustwasm/wasm-bindgen#119) of - // using threads causing weird hangs and bugs. Disable it entirely as - // this isn't yet the bottleneck of compilation at all anyway. - self.cmd.arg("--no-threads"); - - // By default LLD only gives us one page of stack (64k) which is a - // little small. Default to a larger stack closer to other PC platforms - // (1MB) and users can always inject their own link-args to override this. - self.cmd.arg("-z").arg("stack-size=1048576"); - - // By default LLD's memory layout is: - // - // 1. First, a blank page - // 2. Next, all static data - // 3. Finally, the main stack (which grows down) - // - // This has the unfortunate consequence that on stack overflows you - // corrupt static data and can cause some exceedingly weird bugs. To - // help detect this a little sooner we instead request that the stack is - // placed before static data. - // - // This means that we'll generate slightly larger binaries as references - // to static data will take more bytes in the ULEB128 encoding, but - // stack overflow will be guaranteed to trap as it underflows instead of - // corrupting static data. - self.cmd.arg("--stack-first"); - - // FIXME we probably shouldn't pass this but instead pass an explicit - // whitelist of symbols we'll allow to be undefined. Unfortunately - // though we can't handle symbols like `log10` that LLVM injects at a - // super late date without actually parsing object files. For now let's - // stick to this and hopefully fix it before stabilization happens. - self.cmd.arg("--allow-undefined"); - - // For now we just never have an entry symbol - self.cmd.arg("--no-entry"); - - // Make the default table accessible - self.cmd.arg("--export-table"); - - // Rust code should never have warnings, and warnings are often - // indicative of bugs, let's prevent them. - self.cmd.arg("--fatal-warnings"); - - let mut cmd = Command::new(""); - ::std::mem::swap(&mut cmd, &mut self.cmd); - cmd - } - - // Not needed for now with LLD - fn group_start(&mut self) {} - fn group_end(&mut self) {} - - fn cross_lang_lto(&mut self) { - // Do nothing for now - } -} |