2022-08-12 16:28:15 -04:00

673 lines
24 KiB
Rust

use libloading::Library;
use rustc_ast as ast;
use rustc_codegen_ssa::traits::CodegenBackend;
use rustc_data_structures::fx::{FxHashMap, FxHashSet};
#[cfg(parallel_compiler)]
use rustc_data_structures::jobserver;
use rustc_data_structures::sync::Lrc;
use rustc_errors::registry::Registry;
#[cfg(parallel_compiler)]
use rustc_middle::ty::tls;
use rustc_parse::validate_attr;
#[cfg(parallel_compiler)]
use rustc_query_impl::{QueryContext, QueryCtxt};
use rustc_session as session;
use rustc_session::config::CheckCfg;
use rustc_session::config::{self, CrateType};
use rustc_session::config::{ErrorOutputType, Input, OutputFilenames};
use rustc_session::lint::{self, BuiltinLintDiagnostics, LintBuffer};
use rustc_session::parse::CrateConfig;
use rustc_session::{early_error, filesearch, output, DiagnosticOutput, Session};
use rustc_span::edition::Edition;
use rustc_span::lev_distance::find_best_match_for_name;
use rustc_span::source_map::FileLoader;
use rustc_span::symbol::{sym, Symbol};
use std::env;
use std::env::consts::{DLL_PREFIX, DLL_SUFFIX};
use std::mem;
#[cfg(not(parallel_compiler))]
use std::panic;
use std::path::{Path, PathBuf};
use std::sync::atomic::{AtomicBool, Ordering};
use std::sync::OnceLock;
use std::thread;
use tracing::info;
/// Function pointer type that constructs a new CodegenBackend.
pub type MakeBackendFn = fn() -> Box<dyn CodegenBackend>;
/// Adds `target_feature = "..."` cfgs for a variety of platform
/// specific features (SSE, NEON etc.).
///
/// This is performed by checking whether a set of permitted features
/// is available on the target machine, by querying LLVM.
pub fn add_configuration(
cfg: &mut CrateConfig,
sess: &mut Session,
codegen_backend: &dyn CodegenBackend,
) {
let tf = sym::target_feature;
let unstable_target_features = codegen_backend.target_features(sess, true);
sess.unstable_target_features.extend(unstable_target_features.iter().cloned());
let target_features = codegen_backend.target_features(sess, false);
sess.target_features.extend(target_features.iter().cloned());
cfg.extend(target_features.into_iter().map(|feat| (tf, Some(feat))));
if sess.crt_static(None) {
cfg.insert((tf, Some(sym::crt_dash_static)));
}
}
pub fn create_session(
sopts: config::Options,
cfg: FxHashSet<(String, Option<String>)>,
check_cfg: CheckCfg,
diagnostic_output: DiagnosticOutput,
file_loader: Option<Box<dyn FileLoader + Send + Sync + 'static>>,
input_path: Option<PathBuf>,
lint_caps: FxHashMap<lint::LintId, lint::Level>,
make_codegen_backend: Option<
Box<dyn FnOnce(&config::Options) -> Box<dyn CodegenBackend> + Send>,
>,
descriptions: Registry,
) -> (Lrc<Session>, Lrc<Box<dyn CodegenBackend>>) {
let codegen_backend = if let Some(make_codegen_backend) = make_codegen_backend {
make_codegen_backend(&sopts)
} else {
get_codegen_backend(
&sopts.maybe_sysroot,
sopts.unstable_opts.codegen_backend.as_ref().map(|name| &name[..]),
)
};
// target_override is documented to be called before init(), so this is okay
let target_override = codegen_backend.target_override(&sopts);
let bundle = match rustc_errors::fluent_bundle(
sopts.maybe_sysroot.clone(),
sysroot_candidates(),
sopts.unstable_opts.translate_lang.clone(),
sopts.unstable_opts.translate_additional_ftl.as_deref(),
sopts.unstable_opts.translate_directionality_markers,
) {
Ok(bundle) => bundle,
Err(e) => {
early_error(sopts.error_format, &format!("failed to load fluent bundle: {e}"));
}
};
let mut sess = session::build_session(
sopts,
input_path,
bundle,
descriptions,
diagnostic_output,
lint_caps,
file_loader,
target_override,
);
codegen_backend.init(&sess);
let mut cfg = config::build_configuration(&sess, config::to_crate_config(cfg));
add_configuration(&mut cfg, &mut sess, &*codegen_backend);
let mut check_cfg = config::to_crate_check_config(check_cfg);
check_cfg.fill_well_known();
sess.parse_sess.config = cfg;
sess.parse_sess.check_config = check_cfg;
(Lrc::new(sess), Lrc::new(codegen_backend))
}
const STACK_SIZE: usize = 8 * 1024 * 1024;
fn get_stack_size() -> Option<usize> {
// FIXME: Hacks on hacks. If the env is trying to override the stack size
// then *don't* set it explicitly.
env::var_os("RUST_MIN_STACK").is_none().then_some(STACK_SIZE)
}
/// Like a `thread::Builder::spawn` followed by a `join()`, but avoids the need
/// for `'static` bounds.
#[cfg(not(parallel_compiler))]
fn scoped_thread<F: FnOnce() -> R + Send, R: Send>(cfg: thread::Builder, f: F) -> R {
// SAFETY: join() is called immediately, so any closure captures are still
// alive.
match unsafe { cfg.spawn_unchecked(f) }.unwrap().join() {
Ok(v) => v,
Err(e) => panic::resume_unwind(e),
}
}
#[cfg(not(parallel_compiler))]
pub fn run_in_thread_pool_with_globals<F: FnOnce() -> R + Send, R: Send>(
edition: Edition,
_threads: usize,
f: F,
) -> R {
let mut cfg = thread::Builder::new().name("rustc".to_string());
if let Some(size) = get_stack_size() {
cfg = cfg.stack_size(size);
}
let main_handler = move || rustc_span::create_session_globals_then(edition, f);
scoped_thread(cfg, main_handler)
}
/// Creates a new thread and forwards information in thread locals to it.
/// The new thread runs the deadlock handler.
/// Must only be called when a deadlock is about to happen.
#[cfg(parallel_compiler)]
unsafe fn handle_deadlock() {
let registry = rustc_rayon_core::Registry::current();
let query_map = tls::with(|tcx| {
QueryCtxt::from_tcx(tcx)
.try_collect_active_jobs()
.expect("active jobs shouldn't be locked in deadlock handler")
});
thread::spawn(move || rustc_query_impl::deadlock(query_map, &registry));
}
#[cfg(parallel_compiler)]
pub fn run_in_thread_pool_with_globals<F: FnOnce() -> R + Send, R: Send>(
edition: Edition,
threads: usize,
f: F,
) -> R {
let mut config = rayon::ThreadPoolBuilder::new()
.thread_name(|_| "rustc".to_string())
.acquire_thread_handler(jobserver::acquire_thread)
.release_thread_handler(jobserver::release_thread)
.num_threads(threads)
.deadlock_handler(|| unsafe { handle_deadlock() });
if let Some(size) = get_stack_size() {
config = config.stack_size(size);
}
let with_pool = move |pool: &rayon::ThreadPool| pool.install(f);
rustc_span::create_session_globals_then(edition, || {
rustc_span::with_session_globals(|session_globals| {
// The main handler runs for each Rayon worker thread and sets up
// the thread local rustc uses. `session_globals` is captured and set
// on the new threads.
let main_handler = move |thread: rayon::ThreadBuilder| {
rustc_span::set_session_globals_then(session_globals, || thread.run())
};
config.build_scoped(main_handler, with_pool).unwrap()
})
})
}
fn load_backend_from_dylib(path: &Path) -> MakeBackendFn {
let lib = unsafe { Library::new(path) }.unwrap_or_else(|err| {
let err = format!("couldn't load codegen backend {:?}: {}", path, err);
early_error(ErrorOutputType::default(), &err);
});
let backend_sym = unsafe { lib.get::<MakeBackendFn>(b"__rustc_codegen_backend") }
.unwrap_or_else(|e| {
let err = format!("couldn't load codegen backend: {}", e);
early_error(ErrorOutputType::default(), &err);
});
// Intentionally leak the dynamic library. We can't ever unload it
// since the library can make things that will live arbitrarily long.
let backend_sym = unsafe { backend_sym.into_raw() };
mem::forget(lib);
*backend_sym
}
/// Get the codegen backend based on the name and specified sysroot.
///
/// A name of `None` indicates that the default backend should be used.
pub fn get_codegen_backend(
maybe_sysroot: &Option<PathBuf>,
backend_name: Option<&str>,
) -> Box<dyn CodegenBackend> {
static LOAD: OnceLock<unsafe fn() -> Box<dyn CodegenBackend>> = OnceLock::new();
let load = LOAD.get_or_init(|| {
let default_codegen_backend = option_env!("CFG_DEFAULT_CODEGEN_BACKEND").unwrap_or("llvm");
match backend_name.unwrap_or(default_codegen_backend) {
filename if filename.contains('.') => load_backend_from_dylib(filename.as_ref()),
#[cfg(feature = "llvm")]
"llvm" => rustc_codegen_llvm::LlvmCodegenBackend::new,
backend_name => get_codegen_sysroot(maybe_sysroot, backend_name),
}
});
// SAFETY: In case of a builtin codegen backend this is safe. In case of an external codegen
// backend we hope that the backend links against the same rustc_driver version. If this is not
// the case, we get UB.
unsafe { load() }
}
// This is used for rustdoc, but it uses similar machinery to codegen backend
// loading, so we leave the code here. It is potentially useful for other tools
// that want to invoke the rustc binary while linking to rustc as well.
pub fn rustc_path<'a>() -> Option<&'a Path> {
static RUSTC_PATH: OnceLock<Option<PathBuf>> = OnceLock::new();
const BIN_PATH: &str = env!("RUSTC_INSTALL_BINDIR");
RUSTC_PATH.get_or_init(|| get_rustc_path_inner(BIN_PATH)).as_ref().map(|v| &**v)
}
fn get_rustc_path_inner(bin_path: &str) -> Option<PathBuf> {
sysroot_candidates().iter().find_map(|sysroot| {
let candidate = sysroot.join(bin_path).join(if cfg!(target_os = "windows") {
"rustc.exe"
} else {
"rustc"
});
candidate.exists().then_some(candidate)
})
}
fn sysroot_candidates() -> Vec<PathBuf> {
let target = session::config::host_triple();
let mut sysroot_candidates = vec![filesearch::get_or_default_sysroot()];
let path = current_dll_path().and_then(|s| s.canonicalize().ok());
if let Some(dll) = path {
// use `parent` twice to chop off the file name and then also the
// directory containing the dll which should be either `lib` or `bin`.
if let Some(path) = dll.parent().and_then(|p| p.parent()) {
// The original `path` pointed at the `rustc_driver` crate's dll.
// Now that dll should only be in one of two locations. The first is
// in the compiler's libdir, for example `$sysroot/lib/*.dll`. The
// other is the target's libdir, for example
// `$sysroot/lib/rustlib/$target/lib/*.dll`.
//
// We don't know which, so let's assume that if our `path` above
// ends in `$target` we *could* be in the target libdir, and always
// assume that we may be in the main libdir.
sysroot_candidates.push(path.to_owned());
if path.ends_with(target) {
sysroot_candidates.extend(
path.parent() // chop off `$target`
.and_then(|p| p.parent()) // chop off `rustlib`
.and_then(|p| p.parent()) // chop off `lib`
.map(|s| s.to_owned()),
);
}
}
}
return sysroot_candidates;
#[cfg(unix)]
fn current_dll_path() -> Option<PathBuf> {
use std::ffi::{CStr, OsStr};
use std::os::unix::prelude::*;
unsafe {
let addr = current_dll_path as usize as *mut _;
let mut info = mem::zeroed();
if libc::dladdr(addr, &mut info) == 0 {
info!("dladdr failed");
return None;
}
if info.dli_fname.is_null() {
info!("dladdr returned null pointer");
return None;
}
let bytes = CStr::from_ptr(info.dli_fname).to_bytes();
let os = OsStr::from_bytes(bytes);
Some(PathBuf::from(os))
}
}
#[cfg(windows)]
fn current_dll_path() -> Option<PathBuf> {
use std::ffi::OsString;
use std::io;
use std::os::windows::prelude::*;
use std::ptr;
use winapi::um::libloaderapi::{
GetModuleFileNameW, GetModuleHandleExW, GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS,
};
unsafe {
let mut module = ptr::null_mut();
let r = GetModuleHandleExW(
GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS,
current_dll_path as usize as *mut _,
&mut module,
);
if r == 0 {
info!("GetModuleHandleExW failed: {}", io::Error::last_os_error());
return None;
}
let mut space = Vec::with_capacity(1024);
let r = GetModuleFileNameW(module, space.as_mut_ptr(), space.capacity() as u32);
if r == 0 {
info!("GetModuleFileNameW failed: {}", io::Error::last_os_error());
return None;
}
let r = r as usize;
if r >= space.capacity() {
info!("our buffer was too small? {}", io::Error::last_os_error());
return None;
}
space.set_len(r);
let os = OsString::from_wide(&space);
Some(PathBuf::from(os))
}
}
}
fn get_codegen_sysroot(maybe_sysroot: &Option<PathBuf>, backend_name: &str) -> MakeBackendFn {
// For now we only allow this function to be called once as it'll dlopen a
// few things, which seems to work best if we only do that once. In
// general this assertion never trips due to the once guard in `get_codegen_backend`,
// but there's a few manual calls to this function in this file we protect
// against.
static LOADED: AtomicBool = AtomicBool::new(false);
assert!(
!LOADED.fetch_or(true, Ordering::SeqCst),
"cannot load the default codegen backend twice"
);
let target = session::config::host_triple();
let sysroot_candidates = sysroot_candidates();
let sysroot = maybe_sysroot
.iter()
.chain(sysroot_candidates.iter())
.map(|sysroot| {
filesearch::make_target_lib_path(sysroot, target).with_file_name("codegen-backends")
})
.find(|f| {
info!("codegen backend candidate: {}", f.display());
f.exists()
});
let sysroot = sysroot.unwrap_or_else(|| {
let candidates = sysroot_candidates
.iter()
.map(|p| p.display().to_string())
.collect::<Vec<_>>()
.join("\n* ");
let err = format!(
"failed to find a `codegen-backends` folder \
in the sysroot candidates:\n* {}",
candidates
);
early_error(ErrorOutputType::default(), &err);
});
info!("probing {} for a codegen backend", sysroot.display());
let d = sysroot.read_dir().unwrap_or_else(|e| {
let err = format!(
"failed to load default codegen backend, couldn't \
read `{}`: {}",
sysroot.display(),
e
);
early_error(ErrorOutputType::default(), &err);
});
let mut file: Option<PathBuf> = None;
let expected_names = &[
format!("rustc_codegen_{}-{}", backend_name, release_str().expect("CFG_RELEASE")),
format!("rustc_codegen_{}", backend_name),
];
for entry in d.filter_map(|e| e.ok()) {
let path = entry.path();
let Some(filename) = path.file_name().and_then(|s| s.to_str()) else { continue };
if !(filename.starts_with(DLL_PREFIX) && filename.ends_with(DLL_SUFFIX)) {
continue;
}
let name = &filename[DLL_PREFIX.len()..filename.len() - DLL_SUFFIX.len()];
if !expected_names.iter().any(|expected| expected == name) {
continue;
}
if let Some(ref prev) = file {
let err = format!(
"duplicate codegen backends found\n\
first: {}\n\
second: {}\n\
",
prev.display(),
path.display()
);
early_error(ErrorOutputType::default(), &err);
}
file = Some(path.clone());
}
match file {
Some(ref s) => load_backend_from_dylib(s),
None => {
let err = format!("unsupported builtin codegen backend `{}`", backend_name);
early_error(ErrorOutputType::default(), &err);
}
}
}
pub(crate) fn check_attr_crate_type(
sess: &Session,
attrs: &[ast::Attribute],
lint_buffer: &mut LintBuffer,
) {
// Unconditionally collect crate types from attributes to make them used
for a in attrs.iter() {
if a.has_name(sym::crate_type) {
if let Some(n) = a.value_str() {
if categorize_crate_type(n).is_some() {
return;
}
if let ast::MetaItemKind::NameValue(spanned) = a.meta_kind().unwrap() {
let span = spanned.span;
let lev_candidate = find_best_match_for_name(
&CRATE_TYPES.iter().map(|(k, _)| *k).collect::<Vec<_>>(),
n,
None,
);
if let Some(candidate) = lev_candidate {
lint_buffer.buffer_lint_with_diagnostic(
lint::builtin::UNKNOWN_CRATE_TYPES,
ast::CRATE_NODE_ID,
span,
"invalid `crate_type` value",
BuiltinLintDiagnostics::UnknownCrateTypes(
span,
"did you mean".to_string(),
format!("\"{}\"", candidate),
),
);
} else {
lint_buffer.buffer_lint(
lint::builtin::UNKNOWN_CRATE_TYPES,
ast::CRATE_NODE_ID,
span,
"invalid `crate_type` value",
);
}
}
} else {
// This is here mainly to check for using a macro, such as
// #![crate_type = foo!()]. That is not supported since the
// crate type needs to be known very early in compilation long
// before expansion. Otherwise, validation would normally be
// caught in AstValidator (via `check_builtin_attribute`), but
// by the time that runs the macro is expanded, and it doesn't
// give an error.
validate_attr::emit_fatal_malformed_builtin_attribute(
&sess.parse_sess,
a,
sym::crate_type,
);
}
}
}
}
const CRATE_TYPES: &[(Symbol, CrateType)] = &[
(sym::rlib, CrateType::Rlib),
(sym::dylib, CrateType::Dylib),
(sym::cdylib, CrateType::Cdylib),
(sym::lib, config::default_lib_output()),
(sym::staticlib, CrateType::Staticlib),
(sym::proc_dash_macro, CrateType::ProcMacro),
(sym::bin, CrateType::Executable),
];
fn categorize_crate_type(s: Symbol) -> Option<CrateType> {
Some(CRATE_TYPES.iter().find(|(key, _)| *key == s)?.1)
}
pub fn collect_crate_types(session: &Session, attrs: &[ast::Attribute]) -> Vec<CrateType> {
// Unconditionally collect crate types from attributes to make them used
let attr_types: Vec<CrateType> = attrs
.iter()
.filter_map(|a| {
if a.has_name(sym::crate_type) {
match a.value_str() {
Some(s) => categorize_crate_type(s),
_ => None,
}
} else {
None
}
})
.collect();
// If we're generating a test executable, then ignore all other output
// styles at all other locations
if session.opts.test {
return vec![CrateType::Executable];
}
// Only check command line flags if present. If no types are specified by
// command line, then reuse the empty `base` Vec to hold the types that
// will be found in crate attributes.
// JUSTIFICATION: before wrapper fn is available
#[allow(rustc::bad_opt_access)]
let mut base = session.opts.crate_types.clone();
if base.is_empty() {
base.extend(attr_types);
if base.is_empty() {
base.push(output::default_output_for_target(session));
} else {
base.sort();
base.dedup();
}
}
base.retain(|crate_type| {
let res = !output::invalid_output_for_target(session, *crate_type);
if !res {
session.warn(&format!(
"dropping unsupported crate type `{}` for target `{}`",
*crate_type, session.opts.target_triple
));
}
res
});
base
}
pub fn build_output_filenames(
input: &Input,
odir: &Option<PathBuf>,
ofile: &Option<PathBuf>,
temps_dir: &Option<PathBuf>,
attrs: &[ast::Attribute],
sess: &Session,
) -> OutputFilenames {
match *ofile {
None => {
// "-" as input file will cause the parser to read from stdin so we
// have to make up a name
// We want to toss everything after the final '.'
let dirpath = (*odir).as_ref().cloned().unwrap_or_default();
// If a crate name is present, we use it as the link name
let stem = sess
.opts
.crate_name
.clone()
.or_else(|| rustc_attr::find_crate_name(sess, attrs).map(|n| n.to_string()))
.unwrap_or_else(|| input.filestem().to_owned());
OutputFilenames::new(
dirpath,
stem,
None,
temps_dir.clone(),
sess.opts.cg.extra_filename.clone(),
sess.opts.output_types.clone(),
)
}
Some(ref out_file) => {
let unnamed_output_types =
sess.opts.output_types.values().filter(|a| a.is_none()).count();
let ofile = if unnamed_output_types > 1 {
sess.warn(
"due to multiple output types requested, the explicitly specified \
output file name will be adapted for each output type",
);
None
} else {
if !sess.opts.cg.extra_filename.is_empty() {
sess.warn("ignoring -C extra-filename flag due to -o flag");
}
Some(out_file.clone())
};
if *odir != None {
sess.warn("ignoring --out-dir flag due to -o flag");
}
OutputFilenames::new(
out_file.parent().unwrap_or_else(|| Path::new("")).to_path_buf(),
out_file.file_stem().unwrap_or_default().to_str().unwrap().to_string(),
ofile,
temps_dir.clone(),
sess.opts.cg.extra_filename.clone(),
sess.opts.output_types.clone(),
)
}
}
}
/// Returns a version string such as "1.46.0 (04488afe3 2020-08-24)"
pub fn version_str() -> Option<&'static str> {
option_env!("CFG_VERSION")
}
/// Returns a version string such as "0.12.0-dev".
pub fn release_str() -> Option<&'static str> {
option_env!("CFG_RELEASE")
}
/// Returns the full SHA1 hash of HEAD of the Git repo from which rustc was built.
pub fn commit_hash_str() -> Option<&'static str> {
option_env!("CFG_VER_HASH")
}
/// Returns the "commit date" of HEAD of the Git repo from which rustc was built as a static string.
pub fn commit_date_str() -> Option<&'static str> {
option_env!("CFG_VER_DATE")
}