778b631ff0
rustc: Update wasm32 support for LLVM 9
This commit brings in a number of minor updates for rustc's support for
the wasm target which has changed in the LLVM 9 update. Notable updates
include:
* The compiler now no longer manually inserts the `producers` section,
instead relying on LLVM to do so. LLVM uses the `llvm.ident` metadata
for the `processed-by` directive (which is now emitted on the wasm
target in this PR) and it uses debuginfo to figure out what `language`
to put in the `producers` section.
* Threaded WebAssembly code now requires different flags to be passed
with LLD. In LLD we now pass:
* `--shared-memory` - required since objects are compiled with
atomics. This also means that the generated memory will be marked as
`shared`.
* `--max-memory=1GB` - required with the `--shared-memory` argument
since shared memories in WebAssembly must have a maximum size. The
1GB number is intended to be a conservative estimate for rustc, but
it should be overridable with `-C link-arg` if necessary.
* `--passive-segments` - this has become the default for multithreaded
memory, but when compiling a threaded module all data segments need
to be marked as passive to ensure they don't re-initialize memory
for each thread. This will also cause LLD to emit a synthetic
function to initialize memory which users will have to arrange to
call.
* The `__heap_base` and `__data_end` globals are explicitly exported
since they're now hidden by default due to the `--export` flags we
pass to LLD.
1230 lines
40 KiB
Rust
1230 lines
40 KiB
Rust
use super::symbol_export;
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use super::command::Command;
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use super::archive;
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use rustc_data_structures::fx::FxHashMap;
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use std::ffi::{OsStr, OsString};
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use std::fs::{self, File};
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use std::io::prelude::*;
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use std::io::{self, BufWriter};
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use std::path::{Path, PathBuf};
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use rustc::hir::def_id::{LOCAL_CRATE, CrateNum};
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use rustc::middle::dependency_format::Linkage;
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use rustc::session::Session;
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use rustc::session::config::{self, CrateType, OptLevel, DebugInfo,
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LinkerPluginLto, Lto};
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use rustc::ty::TyCtxt;
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use rustc_target::spec::{LinkerFlavor, LldFlavor};
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use rustc_serialize::{json, Encoder};
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/// For all the linkers we support, and information they might
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/// need out of the shared crate context before we get rid of it.
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pub struct LinkerInfo {
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exports: FxHashMap<CrateType, Vec<String>>,
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}
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impl LinkerInfo {
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pub fn new(tcx: TyCtxt<'_>) -> LinkerInfo {
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LinkerInfo {
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exports: tcx.sess.crate_types.borrow().iter().map(|&c| {
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(c, exported_symbols(tcx, c))
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}).collect(),
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}
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}
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pub fn to_linker<'a>(
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&'a self,
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cmd: Command,
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sess: &'a Session,
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flavor: LinkerFlavor,
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target_cpu: &'a str,
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) -> Box<dyn Linker+'a> {
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match flavor {
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LinkerFlavor::Lld(LldFlavor::Link) |
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LinkerFlavor::Msvc => {
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Box::new(MsvcLinker {
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cmd,
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sess,
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info: self
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}) as Box<dyn Linker>
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}
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LinkerFlavor::Em => {
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Box::new(EmLinker {
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cmd,
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sess,
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info: self
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}) as Box<dyn Linker>
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}
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LinkerFlavor::Gcc => {
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Box::new(GccLinker {
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cmd,
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sess,
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info: self,
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hinted_static: false,
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is_ld: false,
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target_cpu,
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}) as Box<dyn Linker>
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}
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LinkerFlavor::Lld(LldFlavor::Ld) |
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LinkerFlavor::Lld(LldFlavor::Ld64) |
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LinkerFlavor::Ld => {
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Box::new(GccLinker {
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cmd,
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sess,
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info: self,
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hinted_static: false,
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is_ld: true,
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target_cpu,
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}) as Box<dyn Linker>
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}
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LinkerFlavor::Lld(LldFlavor::Wasm) => {
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Box::new(WasmLd::new(cmd, sess, self)) as Box<dyn Linker>
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}
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LinkerFlavor::PtxLinker => {
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Box::new(PtxLinker { cmd, sess }) as Box<dyn Linker>
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}
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}
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}
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}
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/// Linker abstraction used by `back::link` to build up the command to invoke a
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/// linker.
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///
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/// This trait is the total list of requirements needed by `back::link` and
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/// represents the meaning of each option being passed down. This trait is then
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/// used to dispatch on whether a GNU-like linker (generally `ld.exe`) or an
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/// MSVC linker (e.g., `link.exe`) is being used.
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pub trait Linker {
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fn link_dylib(&mut self, lib: &str);
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fn link_rust_dylib(&mut self, lib: &str, path: &Path);
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fn link_framework(&mut self, framework: &str);
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fn link_staticlib(&mut self, lib: &str);
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fn link_rlib(&mut self, lib: &Path);
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fn link_whole_rlib(&mut self, lib: &Path);
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fn link_whole_staticlib(&mut self, lib: &str, search_path: &[PathBuf]);
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fn include_path(&mut self, path: &Path);
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fn framework_path(&mut self, path: &Path);
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fn output_filename(&mut self, path: &Path);
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fn add_object(&mut self, path: &Path);
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fn gc_sections(&mut self, keep_metadata: bool);
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fn position_independent_executable(&mut self);
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fn no_position_independent_executable(&mut self);
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fn full_relro(&mut self);
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fn partial_relro(&mut self);
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fn no_relro(&mut self);
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fn optimize(&mut self);
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fn pgo_gen(&mut self);
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fn debuginfo(&mut self);
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fn no_default_libraries(&mut self);
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fn build_dylib(&mut self, out_filename: &Path);
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fn build_static_executable(&mut self);
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fn args(&mut self, args: &[String]);
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fn export_symbols(&mut self, tmpdir: &Path, crate_type: CrateType);
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fn subsystem(&mut self, subsystem: &str);
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fn group_start(&mut self);
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fn group_end(&mut self);
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fn linker_plugin_lto(&mut self);
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// Should have been finalize(self), but we don't support self-by-value on trait objects (yet?).
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fn finalize(&mut self) -> Command;
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}
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pub struct GccLinker<'a> {
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cmd: Command,
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sess: &'a Session,
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info: &'a LinkerInfo,
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hinted_static: bool, // Keeps track of the current hinting mode.
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// Link as ld
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is_ld: bool,
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target_cpu: &'a str,
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}
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impl<'a> GccLinker<'a> {
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/// Argument that must be passed *directly* to the linker
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///
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/// These arguments need to be prepended with `-Wl`, when a GCC-style linker is used.
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fn linker_arg<S>(&mut self, arg: S) -> &mut Self
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where S: AsRef<OsStr>
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{
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if !self.is_ld {
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let mut os = OsString::from("-Wl,");
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os.push(arg.as_ref());
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self.cmd.arg(os);
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} else {
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self.cmd.arg(arg);
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}
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self
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}
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fn takes_hints(&self) -> bool {
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// Really this function only returns true if the underlying linker
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// configured for a compiler is binutils `ld.bfd` and `ld.gold`. We
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// don't really have a foolproof way to detect that, so rule out some
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// platforms where currently this is guaranteed to *not* be the case:
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//
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// * On OSX they have their own linker, not binutils'
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// * For WebAssembly the only functional linker is LLD, which doesn't
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// support hint flags
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!self.sess.target.target.options.is_like_osx &&
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self.sess.target.target.arch != "wasm32"
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}
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// Some platforms take hints about whether a library is static or dynamic.
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// For those that support this, we ensure we pass the option if the library
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// was flagged "static" (most defaults are dynamic) to ensure that if
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// libfoo.a and libfoo.so both exist that the right one is chosen.
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fn hint_static(&mut self) {
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if !self.takes_hints() { return }
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if !self.hinted_static {
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self.linker_arg("-Bstatic");
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self.hinted_static = true;
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}
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}
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fn hint_dynamic(&mut self) {
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if !self.takes_hints() { return }
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if self.hinted_static {
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self.linker_arg("-Bdynamic");
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self.hinted_static = false;
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}
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}
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fn push_linker_plugin_lto_args(&mut self, plugin_path: Option<&OsStr>) {
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if let Some(plugin_path) = plugin_path {
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let mut arg = OsString::from("-plugin=");
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arg.push(plugin_path);
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self.linker_arg(&arg);
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}
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let opt_level = match self.sess.opts.optimize {
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config::OptLevel::No => "O0",
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config::OptLevel::Less => "O1",
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config::OptLevel::Default => "O2",
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config::OptLevel::Aggressive => "O3",
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config::OptLevel::Size => "Os",
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config::OptLevel::SizeMin => "Oz",
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};
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self.linker_arg(&format!("-plugin-opt={}", opt_level));
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let target_cpu = self.target_cpu;
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self.linker_arg(&format!("-plugin-opt=mcpu={}", target_cpu));
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}
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}
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impl<'a> Linker for GccLinker<'a> {
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fn link_dylib(&mut self, lib: &str) { self.hint_dynamic(); self.cmd.arg(format!("-l{}", lib)); }
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fn link_staticlib(&mut self, lib: &str) {
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self.hint_static(); self.cmd.arg(format!("-l{}", lib));
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}
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fn link_rlib(&mut self, lib: &Path) { self.hint_static(); self.cmd.arg(lib); }
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fn include_path(&mut self, path: &Path) { self.cmd.arg("-L").arg(path); }
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fn framework_path(&mut self, path: &Path) { self.cmd.arg("-F").arg(path); }
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fn output_filename(&mut self, path: &Path) { self.cmd.arg("-o").arg(path); }
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fn add_object(&mut self, path: &Path) { self.cmd.arg(path); }
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fn position_independent_executable(&mut self) { self.cmd.arg("-pie"); }
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fn no_position_independent_executable(&mut self) { self.cmd.arg("-no-pie"); }
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fn full_relro(&mut self) { self.linker_arg("-zrelro"); self.linker_arg("-znow"); }
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fn partial_relro(&mut self) { self.linker_arg("-zrelro"); }
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fn no_relro(&mut self) { self.linker_arg("-znorelro"); }
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fn build_static_executable(&mut self) { self.cmd.arg("-static"); }
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fn args(&mut self, args: &[String]) { self.cmd.args(args); }
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fn link_rust_dylib(&mut self, lib: &str, _path: &Path) {
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self.hint_dynamic();
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self.cmd.arg(format!("-l{}", lib));
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}
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fn link_framework(&mut self, framework: &str) {
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self.hint_dynamic();
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self.cmd.arg("-framework").arg(framework);
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}
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// Here we explicitly ask that the entire archive is included into the
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// result artifact. For more details see #15460, but the gist is that
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// the linker will strip away any unused objects in the archive if we
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// don't otherwise explicitly reference them. This can occur for
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// libraries which are just providing bindings, libraries with generic
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// functions, etc.
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fn link_whole_staticlib(&mut self, lib: &str, search_path: &[PathBuf]) {
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self.hint_static();
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let target = &self.sess.target.target;
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if !target.options.is_like_osx {
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self.linker_arg("--whole-archive").cmd.arg(format!("-l{}", lib));
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self.linker_arg("--no-whole-archive");
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} else {
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// -force_load is the macOS equivalent of --whole-archive, but it
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// involves passing the full path to the library to link.
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self.linker_arg("-force_load");
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let lib = archive::find_library(lib, search_path, &self.sess);
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self.linker_arg(&lib);
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}
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}
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fn link_whole_rlib(&mut self, lib: &Path) {
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self.hint_static();
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if self.sess.target.target.options.is_like_osx {
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self.linker_arg("-force_load");
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self.linker_arg(&lib);
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} else {
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self.linker_arg("--whole-archive").cmd.arg(lib);
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self.linker_arg("--no-whole-archive");
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}
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}
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fn gc_sections(&mut self, keep_metadata: bool) {
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// The dead_strip option to the linker specifies that functions and data
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// unreachable by the entry point will be removed. This is quite useful
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// with Rust's compilation model of compiling libraries at a time into
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// one object file. For example, this brings hello world from 1.7MB to
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// 458K.
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//
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// Note that this is done for both executables and dynamic libraries. We
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// won't get much benefit from dylibs because LLVM will have already
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// stripped away as much as it could. This has not been seen to impact
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// link times negatively.
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//
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// -dead_strip can't be part of the pre_link_args because it's also used
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// for partial linking when using multiple codegen units (-r). So we
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// insert it here.
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if self.sess.target.target.options.is_like_osx {
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self.linker_arg("-dead_strip");
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} else if self.sess.target.target.options.is_like_solaris {
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self.linker_arg("-zignore");
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// If we're building a dylib, we don't use --gc-sections because LLVM
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// has already done the best it can do, and we also don't want to
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// eliminate the metadata. If we're building an executable, however,
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// --gc-sections drops the size of hello world from 1.8MB to 597K, a 67%
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// reduction.
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} else if !keep_metadata {
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self.linker_arg("--gc-sections");
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}
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}
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fn optimize(&mut self) {
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if !self.sess.target.target.options.linker_is_gnu { return }
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// GNU-style linkers support optimization with -O. GNU ld doesn't
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// need a numeric argument, but other linkers do.
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if self.sess.opts.optimize == config::OptLevel::Default ||
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self.sess.opts.optimize == config::OptLevel::Aggressive {
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self.linker_arg("-O1");
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}
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}
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fn pgo_gen(&mut self) {
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if !self.sess.target.target.options.linker_is_gnu { return }
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// If we're doing PGO generation stuff and on a GNU-like linker, use the
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// "-u" flag to properly pull in the profiler runtime bits.
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//
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// This is because LLVM otherwise won't add the needed initialization
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// for us on Linux (though the extra flag should be harmless if it
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// does).
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//
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// See https://reviews.llvm.org/D14033 and https://reviews.llvm.org/D14030.
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//
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// Though it may be worth to try to revert those changes upstream, since
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// the overhead of the initialization should be minor.
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self.cmd.arg("-u");
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self.cmd.arg("__llvm_profile_runtime");
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}
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fn debuginfo(&mut self) {
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if let DebugInfo::None = self.sess.opts.debuginfo {
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// If we are building without debuginfo enabled and we were called with
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// `-Zstrip-debuginfo-if-disabled=yes`, tell the linker to strip any debuginfo
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// found when linking to get rid of symbols from libstd.
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if let Some(true) = self.sess.opts.debugging_opts.strip_debuginfo_if_disabled {
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self.linker_arg("-S");
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}
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};
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}
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fn no_default_libraries(&mut self) {
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if !self.is_ld {
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self.cmd.arg("-nodefaultlibs");
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}
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}
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fn build_dylib(&mut self, out_filename: &Path) {
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// On mac we need to tell the linker to let this library be rpathed
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if self.sess.target.target.options.is_like_osx {
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self.cmd.arg("-dynamiclib");
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self.linker_arg("-dylib");
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// Note that the `osx_rpath_install_name` option here is a hack
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// purely to support rustbuild right now, we should get a more
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// principled solution at some point to force the compiler to pass
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// the right `-Wl,-install_name` with an `@rpath` in it.
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if self.sess.opts.cg.rpath || self.sess.opts.debugging_opts.osx_rpath_install_name {
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self.linker_arg("-install_name");
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let mut v = OsString::from("@rpath/");
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v.push(out_filename.file_name().unwrap());
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self.linker_arg(&v);
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}
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} else {
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self.cmd.arg("-shared");
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if self.sess.target.target.options.is_like_windows {
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// The output filename already contains `dll_suffix` so
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// the resulting import library will have a name in the
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// form of libfoo.dll.a
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let implib_name = out_filename
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.file_name()
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.and_then(|file| file.to_str())
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.map(|file| format!("{}{}{}",
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self.sess.target.target.options.staticlib_prefix,
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file,
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self.sess.target.target.options.staticlib_suffix));
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if let Some(implib_name) = implib_name {
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let implib = out_filename
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.parent()
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.map(|dir| dir.join(&implib_name));
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if let Some(implib) = implib {
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self.linker_arg(&format!("--out-implib,{}", (*implib).to_str().unwrap()));
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}
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}
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}
|
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}
|
|
}
|
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|
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fn export_symbols(&mut self, tmpdir: &Path, crate_type: CrateType) {
|
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// Symbol visibility in object files typically takes care of this.
|
|
if crate_type == CrateType::Executable {
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return;
|
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}
|
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|
|
// 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,
|
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// so we hide them all here.
|
|
|
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if !self.sess.target.target.options.limit_rdylib_exports {
|
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return;
|
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}
|
|
|
|
if crate_type == CrateType::ProcMacro {
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return
|
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}
|
|
|
|
let mut arg = OsString::new();
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let path = tmpdir.join("list");
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|
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debug!("EXPORTED SYMBOLS:");
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|
|
if self.sess.target.target.options.is_like_osx {
|
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// Write a plain, newline-separated list of symbols
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|
let res: io::Result<()> = try {
|
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let mut f = BufWriter::new(File::create(&path)?);
|
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for sym in self.info.exports[&crate_type].iter() {
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debug!(" _{}", sym);
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writeln!(f, "_{}", sym)?;
|
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}
|
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};
|
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if let Err(e) = res {
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self.sess.fatal(&format!("failed to write lib.def file: {}", e));
|
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}
|
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} else {
|
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// Write an LD version script
|
|
let res: io::Result<()> = try {
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let mut f = BufWriter::new(File::create(&path)?);
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writeln!(f, "{{\n global:")?;
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for sym in self.info.exports[&crate_type].iter() {
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debug!(" {};", sym);
|
|
writeln!(f, " {};", sym)?;
|
|
}
|
|
writeln!(f, "\n local:\n *;\n}};")?;
|
|
};
|
|
if let Err(e) = res {
|
|
self.sess.fatal(&format!("failed to write version script: {}", e));
|
|
}
|
|
}
|
|
|
|
if self.sess.target.target.options.is_like_osx {
|
|
if !self.is_ld {
|
|
arg.push("-Wl,")
|
|
}
|
|
arg.push("-exported_symbols_list,");
|
|
} else if self.sess.target.target.options.is_like_solaris {
|
|
if !self.is_ld {
|
|
arg.push("-Wl,")
|
|
}
|
|
arg.push("-M,");
|
|
} else {
|
|
if !self.is_ld {
|
|
arg.push("-Wl,")
|
|
}
|
|
arg.push("--version-script=");
|
|
}
|
|
|
|
arg.push(&path);
|
|
self.cmd.arg(arg);
|
|
}
|
|
|
|
fn subsystem(&mut self, subsystem: &str) {
|
|
self.linker_arg("--subsystem");
|
|
self.linker_arg(&subsystem);
|
|
}
|
|
|
|
fn finalize(&mut self) -> Command {
|
|
self.hint_dynamic(); // Reset to default before returning the composed command line.
|
|
|
|
::std::mem::replace(&mut self.cmd, Command::new(""))
|
|
}
|
|
|
|
fn group_start(&mut self) {
|
|
if self.takes_hints() {
|
|
self.linker_arg("--start-group");
|
|
}
|
|
}
|
|
|
|
fn group_end(&mut self) {
|
|
if self.takes_hints() {
|
|
self.linker_arg("--end-group");
|
|
}
|
|
}
|
|
|
|
fn linker_plugin_lto(&mut self) {
|
|
match self.sess.opts.cg.linker_plugin_lto {
|
|
LinkerPluginLto::Disabled => {
|
|
// Nothing to do
|
|
}
|
|
LinkerPluginLto::LinkerPluginAuto => {
|
|
self.push_linker_plugin_lto_args(None);
|
|
}
|
|
LinkerPluginLto::LinkerPlugin(ref path) => {
|
|
self.push_linker_plugin_lto_args(Some(path.as_os_str()));
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
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 PDB file
|
|
let natvis_dir_path = self.sess.sysroot.join("lib\\rustlib\\etc");
|
|
if let Ok(natvis_dir) = fs::read_dir(&natvis_dir_path) {
|
|
for entry in natvis_dir {
|
|
match entry {
|
|
Ok(entry) => {
|
|
let path = entry.path();
|
|
if path.extension() == Some("natvis".as_ref()) {
|
|
let mut arg = OsString::from("/NATVIS:");
|
|
arg.push(path);
|
|
self.cmd.arg(arg);
|
|
}
|
|
},
|
|
Err(err) => {
|
|
self.sess.warn(&format!("error enumerating natvis directory: {}", err));
|
|
},
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// Currently the compiler doesn't use `dllexport` (an LLVM attribute) to
|
|
// export symbols from a dynamic library. When building a dynamic library,
|
|
// however, we're going to want some symbols exported, so this function
|
|
// generates a DEF file which lists all the symbols.
|
|
//
|
|
// The linker will read this `*.def` file and export all the symbols from
|
|
// the dynamic library. Note that this is not as simple as just exporting
|
|
// all the symbols in the current crate (as specified by `codegen.reachable`)
|
|
// but rather we also need to possibly export the symbols of upstream
|
|
// crates. Upstream rlibs may be linked statically to this dynamic library,
|
|
// in which case they may continue to transitively be used and hence need
|
|
// their symbols exported.
|
|
fn export_symbols(&mut self,
|
|
tmpdir: &Path,
|
|
crate_type: CrateType) {
|
|
// Symbol visibility takes care of this typically
|
|
if crate_type == CrateType::Executable {
|
|
return;
|
|
}
|
|
|
|
let path = tmpdir.join("lib.def");
|
|
let res: io::Result<()> = try {
|
|
let mut f = BufWriter::new(File::create(&path)?);
|
|
|
|
// Start off with the standard module name header and then go
|
|
// straight to exports.
|
|
writeln!(f, "LIBRARY")?;
|
|
writeln!(f, "EXPORTS")?;
|
|
for symbol in self.info.exports[&crate_type].iter() {
|
|
debug!(" _{}", symbol);
|
|
writeln!(f, " {}", symbol)?;
|
|
}
|
|
};
|
|
if let Err(e) = res {
|
|
self.sess.fatal(&format!("failed to write lib.def file: {}", e));
|
|
}
|
|
let mut arg = OsString::from("/DEF:");
|
|
arg.push(path);
|
|
self.cmd.arg(&arg);
|
|
}
|
|
|
|
fn subsystem(&mut self, subsystem: &str) {
|
|
// Note that previous passes of the compiler validated this subsystem,
|
|
// so we just blindly pass it to the linker.
|
|
self.cmd.arg(&format!("/SUBSYSTEM:{}", subsystem));
|
|
|
|
// Windows has two subsystems we're interested in right now, the console
|
|
// and windows subsystems. These both implicitly have different entry
|
|
// points (starting symbols). The console entry point starts with
|
|
// `mainCRTStartup` and the windows entry point starts with
|
|
// `WinMainCRTStartup`. These entry points, defined in system libraries,
|
|
// will then later probe for either `main` or `WinMain`, respectively to
|
|
// start the application.
|
|
//
|
|
// In Rust we just always generate a `main` function so we want control
|
|
// to always start there, so we force the entry point on the windows
|
|
// subsystem to be `mainCRTStartup` to get everything booted up
|
|
// correctly.
|
|
//
|
|
// For more information see RFC #1665
|
|
if subsystem == "windows" {
|
|
self.cmd.arg("/ENTRY:mainCRTStartup");
|
|
}
|
|
}
|
|
|
|
fn finalize(&mut self) -> Command {
|
|
::std::mem::replace(&mut self.cmd, Command::new(""))
|
|
}
|
|
|
|
// MSVC doesn't need group indicators
|
|
fn group_start(&mut self) {}
|
|
fn group_end(&mut self) {}
|
|
|
|
fn linker_plugin_lto(&mut self) {
|
|
// Do nothing
|
|
}
|
|
}
|
|
|
|
pub struct EmLinker<'a> {
|
|
cmd: Command,
|
|
sess: &'a Session,
|
|
info: &'a LinkerInfo
|
|
}
|
|
|
|
impl<'a> Linker for EmLinker<'a> {
|
|
fn 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_owned() + sym))
|
|
})?;
|
|
}
|
|
Ok(())
|
|
});
|
|
if let Err(e) = res {
|
|
self.sess.fatal(&format!("failed to encode exported symbols: {}", e));
|
|
}
|
|
}
|
|
debug!("{}", encoded);
|
|
arg.push(encoded);
|
|
|
|
self.cmd.arg(arg);
|
|
}
|
|
|
|
fn subsystem(&mut self, _subsystem: &str) {
|
|
// noop
|
|
}
|
|
|
|
fn finalize(&mut self) -> Command {
|
|
::std::mem::replace(&mut self.cmd, Command::new(""))
|
|
}
|
|
|
|
// Appears not necessary on Emscripten
|
|
fn group_start(&mut self) {}
|
|
fn group_end(&mut self) {}
|
|
|
|
fn linker_plugin_lto(&mut self) {
|
|
// Do nothing
|
|
}
|
|
}
|
|
|
|
pub struct WasmLd<'a> {
|
|
cmd: Command,
|
|
sess: &'a Session,
|
|
info: &'a LinkerInfo,
|
|
}
|
|
|
|
impl<'a> WasmLd<'a> {
|
|
fn new(mut cmd: Command, sess: &'a Session, info: &'a LinkerInfo) -> WasmLd<'a> {
|
|
// If the atomics feature is enabled for wasm then we need a whole bunch
|
|
// of flags:
|
|
//
|
|
// * `--shared-memory` - the link won't even succeed without this, flags
|
|
// the one linear memory as `shared`
|
|
//
|
|
// * `--max-memory=1G` - when specifying a shared memory this must also
|
|
// be specified. We conservatively choose 1GB but users should be able
|
|
// to override this with `-C link-arg`.
|
|
//
|
|
// * `--import-memory` - it doesn't make much sense for memory to be
|
|
// exported in a threaded module because typically you're
|
|
// sharing memory and instantiating the module multiple times. As a
|
|
// result if it were exported then we'd just have no sharing.
|
|
//
|
|
// * `--passive-segments` - all memory segments should be passive to
|
|
// prevent each module instantiation from reinitializing memory.
|
|
//
|
|
// * `--export=__wasm_init_memory` - when using `--passive-segments` the
|
|
// linker will synthesize this function, and so we need to make sure
|
|
// that our usage of `--export` below won't accidentally cause this
|
|
// function to get deleted.
|
|
//
|
|
// * `--export=*tls*` - when `#[thread_local]` symbols are used these
|
|
// symbols are how the TLS segments are initialized and configured.
|
|
let atomics = sess.opts.cg.target_feature.contains("+atomics") ||
|
|
sess.target.target.options.features.contains("+atomics");
|
|
if atomics {
|
|
cmd.arg("--shared-memory");
|
|
cmd.arg("--max-memory=1073741824");
|
|
cmd.arg("--import-memory");
|
|
cmd.arg("--passive-segments");
|
|
cmd.arg("--export=__wasm_init_memory");
|
|
cmd.arg("--export=__wasm_init_tls");
|
|
cmd.arg("--export=__tls_size");
|
|
cmd.arg("--export=__tls_align");
|
|
cmd.arg("--export=__tls_base");
|
|
}
|
|
WasmLd { cmd, sess, info }
|
|
}
|
|
}
|
|
|
|
impl<'a> Linker for WasmLd<'a> {
|
|
fn 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) {
|
|
self.cmd.arg("--no-entry");
|
|
}
|
|
|
|
fn export_symbols(&mut self, _tmpdir: &Path, crate_type: CrateType) {
|
|
for sym in self.info.exports[&crate_type].iter() {
|
|
self.cmd.arg("--export").arg(&sym);
|
|
}
|
|
|
|
// LLD will hide these otherwise-internal symbols since our `--export`
|
|
// list above is a whitelist of what to export. Various bits and pieces
|
|
// of tooling use this, so be sure these symbols make their way out of
|
|
// the linker as well.
|
|
self.cmd.arg("--export=__heap_base");
|
|
self.cmd.arg("--export=__data_end");
|
|
}
|
|
|
|
fn subsystem(&mut self, _subsystem: &str) {
|
|
}
|
|
|
|
fn no_position_independent_executable(&mut self) {
|
|
}
|
|
|
|
fn finalize(&mut self) -> Command {
|
|
::std::mem::replace(&mut self.cmd, Command::new(""))
|
|
}
|
|
|
|
// Not needed for now with LLD
|
|
fn group_start(&mut self) {}
|
|
fn group_end(&mut self) {}
|
|
|
|
fn linker_plugin_lto(&mut self) {
|
|
// Do nothing for now
|
|
}
|
|
}
|
|
|
|
fn exported_symbols(tcx: TyCtxt<'_>, crate_type: CrateType) -> Vec<String> {
|
|
if let Some(ref exports) = tcx.sess.target.target.options.override_export_symbols {
|
|
return exports.clone()
|
|
}
|
|
|
|
let mut symbols = Vec::new();
|
|
|
|
let export_threshold = symbol_export::crates_export_threshold(&[crate_type]);
|
|
for &(symbol, level) in tcx.exported_symbols(LOCAL_CRATE).iter() {
|
|
if level.is_below_threshold(export_threshold) {
|
|
symbols.push(symbol.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
|
|
}
|
|
|
|
/// Much simplified and explicit CLI for the NVPTX linker. The linker operates
|
|
/// with bitcode and uses LLVM backend to generate a PTX assembly.
|
|
pub struct PtxLinker<'a> {
|
|
cmd: Command,
|
|
sess: &'a Session,
|
|
}
|
|
|
|
impl<'a> Linker for PtxLinker<'a> {
|
|
fn link_rlib(&mut self, path: &Path) {
|
|
self.cmd.arg("--rlib").arg(path);
|
|
}
|
|
|
|
fn link_whole_rlib(&mut self, path: &Path) {
|
|
self.cmd.arg("--rlib").arg(path);
|
|
}
|
|
|
|
fn include_path(&mut self, path: &Path) {
|
|
self.cmd.arg("-L").arg(path);
|
|
}
|
|
|
|
fn debuginfo(&mut self) {
|
|
self.cmd.arg("--debug");
|
|
}
|
|
|
|
fn add_object(&mut self, path: &Path) {
|
|
self.cmd.arg("--bitcode").arg(path);
|
|
}
|
|
|
|
fn args(&mut self, args: &[String]) {
|
|
self.cmd.args(args);
|
|
}
|
|
|
|
fn optimize(&mut self) {
|
|
match self.sess.lto() {
|
|
Lto::Thin | Lto::Fat | Lto::ThinLocal => {
|
|
self.cmd.arg("-Olto");
|
|
},
|
|
|
|
Lto::No => { },
|
|
};
|
|
}
|
|
|
|
fn output_filename(&mut self, path: &Path) {
|
|
self.cmd.arg("-o").arg(path);
|
|
}
|
|
|
|
fn finalize(&mut self) -> Command {
|
|
// Provide the linker with fallback to internal `target-cpu`.
|
|
self.cmd.arg("--fallback-arch").arg(match self.sess.opts.cg.target_cpu {
|
|
Some(ref s) => s,
|
|
None => &self.sess.target.target.options.cpu
|
|
});
|
|
|
|
::std::mem::replace(&mut self.cmd, Command::new(""))
|
|
}
|
|
|
|
fn link_dylib(&mut self, _lib: &str) {
|
|
panic!("external dylibs not supported")
|
|
}
|
|
|
|
fn link_rust_dylib(&mut self, _lib: &str, _path: &Path) {
|
|
panic!("external dylibs not supported")
|
|
}
|
|
|
|
fn link_staticlib(&mut self, _lib: &str) {
|
|
panic!("staticlibs not supported")
|
|
}
|
|
|
|
fn link_whole_staticlib(&mut self, _lib: &str, _search_path: &[PathBuf]) {
|
|
panic!("staticlibs not supported")
|
|
}
|
|
|
|
fn framework_path(&mut self, _path: &Path) {
|
|
panic!("frameworks not supported")
|
|
}
|
|
|
|
fn link_framework(&mut self, _framework: &str) {
|
|
panic!("frameworks not supported")
|
|
}
|
|
|
|
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 gc_sections(&mut self, _keep_metadata: bool) {
|
|
}
|
|
|
|
fn pgo_gen(&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) {
|
|
}
|
|
|
|
fn subsystem(&mut self, _subsystem: &str) {
|
|
}
|
|
|
|
fn no_position_independent_executable(&mut self) {
|
|
}
|
|
|
|
fn group_start(&mut self) {
|
|
}
|
|
|
|
fn group_end(&mut self) {
|
|
}
|
|
|
|
fn linker_plugin_lto(&mut self) {
|
|
}
|
|
}
|