| // 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 std::collections::HashMap; |
| 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, DebugInfoLevel}; |
| use rustc::ty::TyCtxt; |
| use rustc_back::LinkerFlavor; |
| use serialize::{json, Encoder}; |
| |
| /// 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: HashMap<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) -> Box<Linker+'a> { |
| match sess.linker_flavor() { |
| LinkerFlavor::Msvc => { |
| Box::new(MsvcLinker { |
| cmd, |
| sess, |
| info: self |
| }) as Box<Linker> |
| } |
| LinkerFlavor::Em => { |
| Box::new(EmLinker { |
| cmd, |
| sess, |
| info: self |
| }) as Box<Linker> |
| } |
| LinkerFlavor::Gcc => { |
| Box::new(GccLinker { |
| cmd, |
| sess, |
| info: self, |
| hinted_static: false, |
| is_ld: false, |
| }) as Box<Linker> |
| } |
| LinkerFlavor::Ld => { |
| Box::new(GccLinker { |
| cmd, |
| sess, |
| info: self, |
| hinted_static: false, |
| is_ld: true, |
| }) as Box<Linker> |
| } |
| LinkerFlavor::Binaryen => { |
| panic!("can't instantiate binaryen 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 partial_relro(&mut self); |
| fn full_relro(&mut self); |
| fn optimize(&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); |
| // 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; |
| } |
| } |
| } |
| |
| impl<'a> Linker for GccLinker<'a> { |
| fn link_dylib(&mut self, lib: &str) { self.hint_dynamic(); self.cmd.arg("-l").arg(lib); } |
| fn link_staticlib(&mut self, lib: &str) { self.hint_static(); self.cmd.arg("-l").arg(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 partial_relro(&mut self) { self.linker_arg("-z,relro"); } |
| fn full_relro(&mut self) { self.linker_arg("-z,relro,-z,now"); } |
| 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("-l").arg(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("-l").arg(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. |
| let mut v = OsString::from("-force_load,"); |
| v.push(&archive::find_library(lib, search_path, &self.sess)); |
| self.linker_arg(&v); |
| } |
| } |
| |
| fn link_whole_rlib(&mut self, lib: &Path) { |
| self.hint_static(); |
| if self.sess.target.target.options.is_like_osx { |
| let mut v = OsString::from("-force_load,"); |
| v.push(lib); |
| self.linker_arg(&v); |
| } 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("-z"); |
| self.linker_arg("ignore"); |
| |
| // 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 debuginfo(&mut self) { |
| // Don't do anything special here for GNU-style linkers. |
| } |
| |
| 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 { |
| let mut v = OsString::from("-install_name,@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::CrateTypeDylib || |
| crate_type == CrateType::CrateTypeProcMacro { |
| 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(&format!("--subsystem,{}", 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 |
| } |
| } |
| |
| 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 partial_relro(&mut self) { |
| // noop |
| } |
| |
| fn full_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 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 `trans.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 |
| } |
| } |
| |
| 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 partial_relro(&mut self) { |
| // noop |
| } |
| |
| fn full_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 debuginfo(&mut self) { |
| // Preserve names or generate source maps depending on debug info |
| self.cmd.arg(match self.sess.opts.debuginfo { |
| DebugInfoLevel::NoDebugInfo => "-g0", |
| DebugInfoLevel::LimitedDebugInfo => "-g3", |
| DebugInfoLevel::FullDebugInfo => "-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 |
| } |
| } |
| |
| 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 &(ref name, _, level) in tcx.exported_symbols(LOCAL_CRATE).iter() { |
| if level.is_below_threshold(export_threshold) { |
| symbols.push(name.clone()); |
| } |
| } |
| |
| 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 &(ref name, _, level) in tcx.exported_symbols(cnum).iter() { |
| if level.is_below_threshold(export_threshold) { |
| symbols.push(name.clone()); |
| } |
| } |
| } |
| } |
| |
| symbols |
| } |
