blob: 14bbe65d5f1fc718cc500b547840e00e32d3697e [file] [log] [blame]
//! Validates all used crates and extern libraries and loads their metadata
use crate::errors;
use crate::locator::{CrateError, CrateLocator, CratePaths};
use crate::rmeta::{CrateDep, CrateMetadata, CrateNumMap, CrateRoot, MetadataBlob};
use rustc_ast::expand::allocator::{alloc_error_handler_name, global_fn_name, AllocatorKind};
use rustc_ast::{self as ast, *};
use rustc_data_structures::fx::FxHashSet;
use rustc_data_structures::svh::Svh;
use rustc_data_structures::sync::{FreezeReadGuard, FreezeWriteGuard};
use rustc_expand::base::SyntaxExtension;
use rustc_fs_util::try_canonicalize;
use rustc_hir::def_id::{CrateNum, LocalDefId, StableCrateId, StableCrateIdMap, LOCAL_CRATE};
use rustc_hir::definitions::Definitions;
use rustc_index::IndexVec;
use rustc_middle::ty::TyCtxt;
use rustc_session::config::{self, CrateType, ExternLocation};
use rustc_session::cstore::{
CrateDepKind, CrateSource, ExternCrate, ExternCrateSource, MetadataLoaderDyn,
};
use rustc_session::lint;
use rustc_session::output::validate_crate_name;
use rustc_session::search_paths::PathKind;
use rustc_span::edition::Edition;
use rustc_span::symbol::{sym, Symbol};
use rustc_span::{Span, DUMMY_SP};
use rustc_target::spec::{PanicStrategy, TargetTriple};
use proc_macro::bridge::client::ProcMacro;
use std::error::Error;
use std::ops::Fn;
use std::path::Path;
use std::time::Duration;
use std::{cmp, iter};
pub struct CStore {
metadata_loader: Box<MetadataLoaderDyn>,
metas: IndexVec<CrateNum, Option<Box<CrateMetadata>>>,
injected_panic_runtime: Option<CrateNum>,
/// This crate needs an allocator and either provides it itself, or finds it in a dependency.
/// If the above is true, then this field denotes the kind of the found allocator.
allocator_kind: Option<AllocatorKind>,
/// This crate needs an allocation error handler and either provides it itself, or finds it in a dependency.
/// If the above is true, then this field denotes the kind of the found allocator.
alloc_error_handler_kind: Option<AllocatorKind>,
/// This crate has a `#[global_allocator]` item.
has_global_allocator: bool,
/// This crate has a `#[alloc_error_handler]` item.
has_alloc_error_handler: bool,
/// The interned [StableCrateId]s.
pub(crate) stable_crate_ids: StableCrateIdMap,
/// Unused externs of the crate
unused_externs: Vec<Symbol>,
}
impl std::fmt::Debug for CStore {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.debug_struct("CStore").finish_non_exhaustive()
}
}
pub struct CrateLoader<'a, 'tcx: 'a> {
// Immutable configuration.
tcx: TyCtxt<'tcx>,
// Mutable output.
cstore: &'a mut CStore,
used_extern_options: &'a mut FxHashSet<Symbol>,
}
impl<'a, 'tcx> std::ops::Deref for CrateLoader<'a, 'tcx> {
type Target = TyCtxt<'tcx>;
fn deref(&self) -> &Self::Target {
&self.tcx
}
}
pub enum LoadedMacro {
MacroDef(ast::Item, Edition),
ProcMacro(SyntaxExtension),
}
pub(crate) struct Library {
pub source: CrateSource,
pub metadata: MetadataBlob,
}
enum LoadResult {
Previous(CrateNum),
Loaded(Library),
}
/// A reference to `CrateMetadata` that can also give access to whole crate store when necessary.
#[derive(Clone, Copy)]
pub(crate) struct CrateMetadataRef<'a> {
pub cdata: &'a CrateMetadata,
pub cstore: &'a CStore,
}
impl std::ops::Deref for CrateMetadataRef<'_> {
type Target = CrateMetadata;
fn deref(&self) -> &Self::Target {
self.cdata
}
}
struct CrateDump<'a>(&'a CStore);
impl<'a> std::fmt::Debug for CrateDump<'a> {
fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
writeln!(fmt, "resolved crates:")?;
for (cnum, data) in self.0.iter_crate_data() {
writeln!(fmt, " name: {}", data.name())?;
writeln!(fmt, " cnum: {cnum}")?;
writeln!(fmt, " hash: {}", data.hash())?;
writeln!(fmt, " reqd: {:?}", data.dep_kind())?;
let CrateSource { dylib, rlib, rmeta } = data.source();
if let Some(dylib) = dylib {
writeln!(fmt, " dylib: {}", dylib.0.display())?;
}
if let Some(rlib) = rlib {
writeln!(fmt, " rlib: {}", rlib.0.display())?;
}
if let Some(rmeta) = rmeta {
writeln!(fmt, " rmeta: {}", rmeta.0.display())?;
}
}
Ok(())
}
}
impl CStore {
pub fn from_tcx(tcx: TyCtxt<'_>) -> FreezeReadGuard<'_, CStore> {
FreezeReadGuard::map(tcx.untracked().cstore.read(), |cstore| {
cstore.as_any().downcast_ref::<CStore>().expect("`tcx.cstore` is not a `CStore`")
})
}
pub fn from_tcx_mut(tcx: TyCtxt<'_>) -> FreezeWriteGuard<'_, CStore> {
FreezeWriteGuard::map(tcx.untracked().cstore.write(), |cstore| {
cstore.untracked_as_any().downcast_mut().expect("`tcx.cstore` is not a `CStore`")
})
}
fn intern_stable_crate_id(&mut self, root: &CrateRoot) -> Result<CrateNum, CrateError> {
assert_eq!(self.metas.len(), self.stable_crate_ids.len());
let num = CrateNum::new(self.stable_crate_ids.len());
if let Some(&existing) = self.stable_crate_ids.get(&root.stable_crate_id()) {
// Check for (potential) conflicts with the local crate
if existing == LOCAL_CRATE {
Err(CrateError::SymbolConflictsCurrent(root.name()))
} else if let Some(crate_name1) = self.metas[existing].as_ref().map(|data| data.name())
{
let crate_name0 = root.name();
Err(CrateError::StableCrateIdCollision(crate_name0, crate_name1))
} else {
Err(CrateError::NotFound(root.name()))
}
} else {
self.metas.push(None);
self.stable_crate_ids.insert(root.stable_crate_id(), num);
Ok(num)
}
}
pub fn has_crate_data(&self, cnum: CrateNum) -> bool {
self.metas[cnum].is_some()
}
pub(crate) fn get_crate_data(&self, cnum: CrateNum) -> CrateMetadataRef<'_> {
let cdata = self.metas[cnum]
.as_ref()
.unwrap_or_else(|| panic!("Failed to get crate data for {cnum:?}"));
CrateMetadataRef { cdata, cstore: self }
}
fn set_crate_data(&mut self, cnum: CrateNum, data: CrateMetadata) {
assert!(self.metas[cnum].is_none(), "Overwriting crate metadata entry");
self.metas[cnum] = Some(Box::new(data));
}
pub(crate) fn iter_crate_data(&self) -> impl Iterator<Item = (CrateNum, &CrateMetadata)> {
self.metas
.iter_enumerated()
.filter_map(|(cnum, data)| data.as_deref().map(|data| (cnum, data)))
}
fn push_dependencies_in_postorder(&self, deps: &mut Vec<CrateNum>, cnum: CrateNum) {
if !deps.contains(&cnum) {
let data = self.get_crate_data(cnum);
for dep in data.dependencies() {
if dep != cnum {
self.push_dependencies_in_postorder(deps, dep);
}
}
deps.push(cnum);
}
}
pub(crate) fn crate_dependencies_in_postorder(&self, cnum: CrateNum) -> Vec<CrateNum> {
let mut deps = Vec::new();
if cnum == LOCAL_CRATE {
for (cnum, _) in self.iter_crate_data() {
self.push_dependencies_in_postorder(&mut deps, cnum);
}
} else {
self.push_dependencies_in_postorder(&mut deps, cnum);
}
deps
}
fn crate_dependencies_in_reverse_postorder(&self, cnum: CrateNum) -> Vec<CrateNum> {
let mut deps = self.crate_dependencies_in_postorder(cnum);
deps.reverse();
deps
}
pub(crate) fn injected_panic_runtime(&self) -> Option<CrateNum> {
self.injected_panic_runtime
}
pub(crate) fn allocator_kind(&self) -> Option<AllocatorKind> {
self.allocator_kind
}
pub(crate) fn alloc_error_handler_kind(&self) -> Option<AllocatorKind> {
self.alloc_error_handler_kind
}
pub(crate) fn has_global_allocator(&self) -> bool {
self.has_global_allocator
}
pub(crate) fn has_alloc_error_handler(&self) -> bool {
self.has_alloc_error_handler
}
pub fn report_unused_deps(&self, tcx: TyCtxt<'_>) {
let json_unused_externs = tcx.sess.opts.json_unused_externs;
// We put the check for the option before the lint_level_at_node call
// because the call mutates internal state and introducing it
// leads to some ui tests failing.
if !json_unused_externs.is_enabled() {
return;
}
let level = tcx
.lint_level_at_node(lint::builtin::UNUSED_CRATE_DEPENDENCIES, rustc_hir::CRATE_HIR_ID)
.0;
if level != lint::Level::Allow {
let unused_externs =
self.unused_externs.iter().map(|ident| ident.to_ident_string()).collect::<Vec<_>>();
let unused_externs = unused_externs.iter().map(String::as_str).collect::<Vec<&str>>();
tcx.sess.parse_sess.span_diagnostic.emit_unused_externs(
level,
json_unused_externs.is_loud(),
&unused_externs,
);
}
}
pub fn new(
metadata_loader: Box<MetadataLoaderDyn>,
local_stable_crate_id: StableCrateId,
) -> CStore {
let mut stable_crate_ids = StableCrateIdMap::default();
stable_crate_ids.insert(local_stable_crate_id, LOCAL_CRATE);
CStore {
metadata_loader,
// We add an empty entry for LOCAL_CRATE (which maps to zero) in
// order to make array indices in `metas` match with the
// corresponding `CrateNum`. This first entry will always remain
// `None`.
metas: IndexVec::from_iter(iter::once(None)),
injected_panic_runtime: None,
allocator_kind: None,
alloc_error_handler_kind: None,
has_global_allocator: false,
has_alloc_error_handler: false,
stable_crate_ids,
unused_externs: Vec::new(),
}
}
}
impl<'a, 'tcx> CrateLoader<'a, 'tcx> {
pub fn new(
tcx: TyCtxt<'tcx>,
cstore: &'a mut CStore,
used_extern_options: &'a mut FxHashSet<Symbol>,
) -> Self {
CrateLoader { tcx, cstore, used_extern_options }
}
fn existing_match(&self, name: Symbol, hash: Option<Svh>, kind: PathKind) -> Option<CrateNum> {
for (cnum, data) in self.cstore.iter_crate_data() {
if data.name() != name {
trace!("{} did not match {}", data.name(), name);
continue;
}
match hash {
Some(hash) if hash == data.hash() => return Some(cnum),
Some(hash) => {
debug!("actual hash {} did not match expected {}", hash, data.hash());
continue;
}
None => {}
}
// When the hash is None we're dealing with a top-level dependency
// in which case we may have a specification on the command line for
// this library. Even though an upstream library may have loaded
// something of the same name, we have to make sure it was loaded
// from the exact same location as well.
//
// We're also sure to compare *paths*, not actual byte slices. The
// `source` stores paths which are normalized which may be different
// from the strings on the command line.
let source = self.cstore.get_crate_data(cnum).cdata.source();
if let Some(entry) = self.sess.opts.externs.get(name.as_str()) {
// Only use `--extern crate_name=path` here, not `--extern crate_name`.
if let Some(mut files) = entry.files() {
if files.any(|l| {
let l = l.canonicalized();
source.dylib.as_ref().map(|(p, _)| p) == Some(l)
|| source.rlib.as_ref().map(|(p, _)| p) == Some(l)
|| source.rmeta.as_ref().map(|(p, _)| p) == Some(l)
}) {
return Some(cnum);
}
}
continue;
}
// Alright, so we've gotten this far which means that `data` has the
// right name, we don't have a hash, and we don't have a --extern
// pointing for ourselves. We're still not quite yet done because we
// have to make sure that this crate was found in the crate lookup
// path (this is a top-level dependency) as we don't want to
// implicitly load anything inside the dependency lookup path.
let prev_kind = source
.dylib
.as_ref()
.or(source.rlib.as_ref())
.or(source.rmeta.as_ref())
.expect("No sources for crate")
.1;
if kind.matches(prev_kind) {
return Some(cnum);
} else {
debug!(
"failed to load existing crate {}; kind {:?} did not match prev_kind {:?}",
name, kind, prev_kind
);
}
}
None
}
fn register_crate(
&mut self,
host_lib: Option<Library>,
root: Option<&CratePaths>,
lib: Library,
dep_kind: CrateDepKind,
name: Symbol,
private_dep: Option<bool>,
) -> Result<CrateNum, CrateError> {
let _prof_timer = self.sess.prof.generic_activity("metadata_register_crate");
let Library { source, metadata } = lib;
let crate_root = metadata.get_root();
let host_hash = host_lib.as_ref().map(|lib| lib.metadata.get_root().hash());
let private_dep = self
.sess
.opts
.externs
.get(name.as_str())
.map_or(private_dep.unwrap_or(false), |e| e.is_private_dep)
&& private_dep.unwrap_or(true);
// Claim this crate number and cache it
let cnum = self.cstore.intern_stable_crate_id(&crate_root)?;
info!(
"register crate `{}` (cnum = {}. private_dep = {})",
crate_root.name(),
cnum,
private_dep
);
// Maintain a reference to the top most crate.
// Stash paths for top-most crate locally if necessary.
let crate_paths;
let root = if let Some(root) = root {
root
} else {
crate_paths = CratePaths::new(crate_root.name(), source.clone());
&crate_paths
};
let cnum_map = self.resolve_crate_deps(root, &crate_root, &metadata, cnum, dep_kind)?;
let raw_proc_macros = if crate_root.is_proc_macro_crate() {
let temp_root;
let (dlsym_source, dlsym_root) = match &host_lib {
Some(host_lib) => (&host_lib.source, {
temp_root = host_lib.metadata.get_root();
&temp_root
}),
None => (&source, &crate_root),
};
let dlsym_dylib = dlsym_source.dylib.as_ref().expect("no dylib for a proc-macro crate");
Some(self.dlsym_proc_macros(&dlsym_dylib.0, dlsym_root.stable_crate_id())?)
} else {
None
};
let crate_metadata = CrateMetadata::new(
self.sess,
&self.cstore,
metadata,
crate_root,
raw_proc_macros,
cnum,
cnum_map,
dep_kind,
source,
private_dep,
host_hash,
);
self.cstore.set_crate_data(cnum, crate_metadata);
Ok(cnum)
}
fn load_proc_macro<'b>(
&self,
locator: &mut CrateLocator<'b>,
path_kind: PathKind,
host_hash: Option<Svh>,
) -> Result<Option<(LoadResult, Option<Library>)>, CrateError>
where
'a: 'b,
{
// Use a new crate locator so trying to load a proc macro doesn't affect the error
// message we emit
let mut proc_macro_locator = locator.clone();
// Try to load a proc macro
proc_macro_locator.is_proc_macro = true;
// Load the proc macro crate for the target
let (locator, target_result) = if self.sess.opts.unstable_opts.dual_proc_macros {
proc_macro_locator.reset();
let result = match self.load(&mut proc_macro_locator)? {
Some(LoadResult::Previous(cnum)) => {
return Ok(Some((LoadResult::Previous(cnum), None)));
}
Some(LoadResult::Loaded(library)) => Some(LoadResult::Loaded(library)),
None => return Ok(None),
};
locator.hash = host_hash;
// Use the locator when looking for the host proc macro crate, as that is required
// so we want it to affect the error message
(locator, result)
} else {
(&mut proc_macro_locator, None)
};
// Load the proc macro crate for the host
locator.reset();
locator.is_proc_macro = true;
locator.target = &self.sess.host;
locator.triple = TargetTriple::from_triple(config::host_triple());
locator.filesearch = self.sess.host_filesearch(path_kind);
let Some(host_result) = self.load(locator)? else {
return Ok(None);
};
Ok(Some(if self.sess.opts.unstable_opts.dual_proc_macros {
let host_result = match host_result {
LoadResult::Previous(..) => {
panic!("host and target proc macros must be loaded in lock-step")
}
LoadResult::Loaded(library) => library,
};
(target_result.unwrap(), Some(host_result))
} else {
(host_result, None)
}))
}
fn resolve_crate(
&mut self,
name: Symbol,
span: Span,
dep_kind: CrateDepKind,
) -> Option<CrateNum> {
self.used_extern_options.insert(name);
match self.maybe_resolve_crate(name, dep_kind, None) {
Ok(cnum) => Some(cnum),
Err(err) => {
let missing_core =
self.maybe_resolve_crate(sym::core, CrateDepKind::Explicit, None).is_err();
err.report(&self.sess, span, missing_core);
None
}
}
}
fn maybe_resolve_crate<'b>(
&'b mut self,
name: Symbol,
mut dep_kind: CrateDepKind,
dep: Option<(&'b CratePaths, &'b CrateDep)>,
) -> Result<CrateNum, CrateError> {
info!("resolving crate `{}`", name);
if !name.as_str().is_ascii() {
return Err(CrateError::NonAsciiName(name));
}
let (root, hash, host_hash, extra_filename, path_kind, private_dep) = match dep {
Some((root, dep)) => (
Some(root),
Some(dep.hash),
dep.host_hash,
Some(&dep.extra_filename[..]),
PathKind::Dependency,
Some(dep.is_private),
),
None => (None, None, None, None, PathKind::Crate, None),
};
let result = if let Some(cnum) = self.existing_match(name, hash, path_kind) {
(LoadResult::Previous(cnum), None)
} else {
info!("falling back to a load");
let mut locator = CrateLocator::new(
self.sess,
&*self.cstore.metadata_loader,
name,
// The all loop is because `--crate-type=rlib --crate-type=rlib` is
// legal and produces both inside this type.
self.tcx.crate_types().iter().all(|c| *c == CrateType::Rlib),
hash,
extra_filename,
false, // is_host
path_kind,
);
match self.load(&mut locator)? {
Some(res) => (res, None),
None => {
dep_kind = CrateDepKind::MacrosOnly;
match self.load_proc_macro(&mut locator, path_kind, host_hash)? {
Some(res) => res,
None => return Err(locator.into_error(root.cloned())),
}
}
}
};
match result {
(LoadResult::Previous(cnum), None) => {
let data = self.cstore.get_crate_data(cnum);
if data.is_proc_macro_crate() {
dep_kind = CrateDepKind::MacrosOnly;
}
data.update_dep_kind(|data_dep_kind| cmp::max(data_dep_kind, dep_kind));
if let Some(private_dep) = private_dep {
data.update_and_private_dep(private_dep);
}
Ok(cnum)
}
(LoadResult::Loaded(library), host_library) => {
self.register_crate(host_library, root, library, dep_kind, name, private_dep)
}
_ => panic!(),
}
}
fn load(&self, locator: &mut CrateLocator<'_>) -> Result<Option<LoadResult>, CrateError> {
let Some(library) = locator.maybe_load_library_crate()? else {
return Ok(None);
};
// In the case that we're loading a crate, but not matching
// against a hash, we could load a crate which has the same hash
// as an already loaded crate. If this is the case prevent
// duplicates by just using the first crate.
//
// Note that we only do this for target triple crates, though, as we
// don't want to match a host crate against an equivalent target one
// already loaded.
let root = library.metadata.get_root();
// FIXME: why is this condition necessary? It was adding in #33625 but I
// don't know why and the original author doesn't remember ...
let can_reuse_cratenum =
locator.triple == self.sess.opts.target_triple || locator.is_proc_macro;
Ok(Some(if can_reuse_cratenum {
let mut result = LoadResult::Loaded(library);
for (cnum, data) in self.cstore.iter_crate_data() {
if data.name() == root.name() && root.hash() == data.hash() {
assert!(locator.hash.is_none());
info!("load success, going to previous cnum: {}", cnum);
result = LoadResult::Previous(cnum);
break;
}
}
result
} else {
LoadResult::Loaded(library)
}))
}
fn update_extern_crate(&self, cnum: CrateNum, extern_crate: ExternCrate) {
let cmeta = self.cstore.get_crate_data(cnum);
if cmeta.update_extern_crate(extern_crate) {
// Propagate the extern crate info to dependencies if it was updated.
let extern_crate = ExternCrate { dependency_of: cnum, ..extern_crate };
for dep_cnum in cmeta.dependencies() {
self.update_extern_crate(dep_cnum, extern_crate);
}
}
}
// Go through the crate metadata and load any crates that it references
fn resolve_crate_deps(
&mut self,
root: &CratePaths,
crate_root: &CrateRoot,
metadata: &MetadataBlob,
krate: CrateNum,
dep_kind: CrateDepKind,
) -> Result<CrateNumMap, CrateError> {
debug!("resolving deps of external crate");
if crate_root.is_proc_macro_crate() {
return Ok(CrateNumMap::new());
}
// The map from crate numbers in the crate we're resolving to local crate numbers.
// We map 0 and all other holes in the map to our parent crate. The "additional"
// self-dependencies should be harmless.
let deps = crate_root.decode_crate_deps(metadata);
let mut crate_num_map = CrateNumMap::with_capacity(1 + deps.len());
crate_num_map.push(krate);
for dep in deps {
info!(
"resolving dep crate {} hash: `{}` extra filename: `{}`",
dep.name, dep.hash, dep.extra_filename
);
let dep_kind = match dep_kind {
CrateDepKind::MacrosOnly => CrateDepKind::MacrosOnly,
_ => dep.kind,
};
let cnum = self.maybe_resolve_crate(dep.name, dep_kind, Some((root, &dep)))?;
crate_num_map.push(cnum);
}
debug!("resolve_crate_deps: cnum_map for {:?} is {:?}", krate, crate_num_map);
Ok(crate_num_map)
}
fn dlsym_proc_macros(
&self,
path: &Path,
stable_crate_id: StableCrateId,
) -> Result<&'static [ProcMacro], CrateError> {
// Make sure the path contains a / or the linker will search for it.
let path = try_canonicalize(path).unwrap();
let lib = load_dylib(&path, 5).map_err(|err| CrateError::DlOpen(err))?;
let sym_name = self.sess.generate_proc_macro_decls_symbol(stable_crate_id);
let sym = unsafe { lib.get::<*const &[ProcMacro]>(sym_name.as_bytes()) }
.map_err(|err| CrateError::DlSym(err.to_string()))?;
// Intentionally leak the dynamic library. We can't ever unload it
// since the library can make things that will live arbitrarily long.
let sym = unsafe { sym.into_raw() };
std::mem::forget(lib);
Ok(unsafe { **sym })
}
fn inject_panic_runtime(&mut self, krate: &ast::Crate) {
// If we're only compiling an rlib, then there's no need to select a
// panic runtime, so we just skip this section entirely.
let any_non_rlib = self.tcx.crate_types().iter().any(|ct| *ct != CrateType::Rlib);
if !any_non_rlib {
info!("panic runtime injection skipped, only generating rlib");
return;
}
// If we need a panic runtime, we try to find an existing one here. At
// the same time we perform some general validation of the DAG we've got
// going such as ensuring everything has a compatible panic strategy.
//
// The logic for finding the panic runtime here is pretty much the same
// as the allocator case with the only addition that the panic strategy
// compilation mode also comes into play.
let desired_strategy = self.sess.panic_strategy();
let mut runtime_found = false;
let mut needs_panic_runtime = attr::contains_name(&krate.attrs, sym::needs_panic_runtime);
for (cnum, data) in self.cstore.iter_crate_data() {
needs_panic_runtime = needs_panic_runtime || data.needs_panic_runtime();
if data.is_panic_runtime() {
// Inject a dependency from all #![needs_panic_runtime] to this
// #![panic_runtime] crate.
self.inject_dependency_if(cnum, "a panic runtime", &|data| {
data.needs_panic_runtime()
});
runtime_found = runtime_found || data.dep_kind() == CrateDepKind::Explicit;
}
}
// If an explicitly linked and matching panic runtime was found, or if
// we just don't need one at all, then we're done here and there's
// nothing else to do.
if !needs_panic_runtime || runtime_found {
return;
}
// By this point we know that we (a) need a panic runtime and (b) no
// panic runtime was explicitly linked. Here we just load an appropriate
// default runtime for our panic strategy and then inject the
// dependencies.
//
// We may resolve to an already loaded crate (as the crate may not have
// been explicitly linked prior to this) and we may re-inject
// dependencies again, but both of those situations are fine.
//
// Also note that we have yet to perform validation of the crate graph
// in terms of everyone has a compatible panic runtime format, that's
// performed later as part of the `dependency_format` module.
let name = match desired_strategy {
PanicStrategy::Unwind => sym::panic_unwind,
PanicStrategy::Abort => sym::panic_abort,
};
info!("panic runtime not found -- loading {}", name);
let Some(cnum) = self.resolve_crate(name, DUMMY_SP, CrateDepKind::Implicit) else {
return;
};
let data = self.cstore.get_crate_data(cnum);
// Sanity check the loaded crate to ensure it is indeed a panic runtime
// and the panic strategy is indeed what we thought it was.
if !data.is_panic_runtime() {
self.sess.emit_err(errors::CrateNotPanicRuntime { crate_name: name });
}
if data.required_panic_strategy() != Some(desired_strategy) {
self.sess
.emit_err(errors::NoPanicStrategy { crate_name: name, strategy: desired_strategy });
}
self.cstore.injected_panic_runtime = Some(cnum);
self.inject_dependency_if(cnum, "a panic runtime", &|data| data.needs_panic_runtime());
}
fn inject_profiler_runtime(&mut self, krate: &ast::Crate) {
if self.sess.opts.unstable_opts.no_profiler_runtime
|| !(self.sess.instrument_coverage()
|| self.sess.opts.unstable_opts.profile
|| self.sess.opts.cg.profile_generate.enabled())
{
return;
}
info!("loading profiler");
let name = Symbol::intern(&self.sess.opts.unstable_opts.profiler_runtime);
if name == sym::profiler_builtins && attr::contains_name(&krate.attrs, sym::no_core) {
self.sess.emit_err(errors::ProfilerBuiltinsNeedsCore);
}
let Some(cnum) = self.resolve_crate(name, DUMMY_SP, CrateDepKind::Implicit) else {
return;
};
let data = self.cstore.get_crate_data(cnum);
// Sanity check the loaded crate to ensure it is indeed a profiler runtime
if !data.is_profiler_runtime() {
self.sess.emit_err(errors::NotProfilerRuntime { crate_name: name });
}
}
fn inject_allocator_crate(&mut self, krate: &ast::Crate) {
self.cstore.has_global_allocator = match &*global_allocator_spans(krate) {
[span1, span2, ..] => {
self.sess.emit_err(errors::NoMultipleGlobalAlloc { span2: *span2, span1: *span1 });
true
}
spans => !spans.is_empty(),
};
self.cstore.has_alloc_error_handler = match &*alloc_error_handler_spans(krate) {
[span1, span2, ..] => {
self.sess
.emit_err(errors::NoMultipleAllocErrorHandler { span2: *span2, span1: *span1 });
true
}
spans => !spans.is_empty(),
};
// Check to see if we actually need an allocator. This desire comes
// about through the `#![needs_allocator]` attribute and is typically
// written down in liballoc.
if !attr::contains_name(&krate.attrs, sym::needs_allocator)
&& !self.cstore.iter_crate_data().any(|(_, data)| data.needs_allocator())
{
return;
}
// At this point we've determined that we need an allocator. Let's see
// if our compilation session actually needs an allocator based on what
// we're emitting.
let all_rlib = self.tcx.crate_types().iter().all(|ct| matches!(*ct, CrateType::Rlib));
if all_rlib {
return;
}
// Ok, we need an allocator. Not only that but we're actually going to
// create an artifact that needs one linked in. Let's go find the one
// that we're going to link in.
//
// First up we check for global allocators. Look at the crate graph here
// and see what's a global allocator, including if we ourselves are a
// global allocator.
let mut global_allocator =
self.cstore.has_global_allocator.then(|| Symbol::intern("this crate"));
for (_, data) in self.cstore.iter_crate_data() {
if data.has_global_allocator() {
match global_allocator {
Some(other_crate) => {
self.sess.emit_err(errors::ConflictingGlobalAlloc {
crate_name: data.name(),
other_crate_name: other_crate,
});
}
None => global_allocator = Some(data.name()),
}
}
}
let mut alloc_error_handler =
self.cstore.has_alloc_error_handler.then(|| Symbol::intern("this crate"));
for (_, data) in self.cstore.iter_crate_data() {
if data.has_alloc_error_handler() {
match alloc_error_handler {
Some(other_crate) => {
self.sess.emit_err(errors::ConflictingAllocErrorHandler {
crate_name: data.name(),
other_crate_name: other_crate,
});
}
None => alloc_error_handler = Some(data.name()),
}
}
}
if global_allocator.is_some() {
self.cstore.allocator_kind = Some(AllocatorKind::Global);
} else {
// Ok we haven't found a global allocator but we still need an
// allocator. At this point our allocator request is typically fulfilled
// by the standard library, denoted by the `#![default_lib_allocator]`
// attribute.
if !attr::contains_name(&krate.attrs, sym::default_lib_allocator)
&& !self.cstore.iter_crate_data().any(|(_, data)| data.has_default_lib_allocator())
{
self.sess.emit_err(errors::GlobalAllocRequired);
}
self.cstore.allocator_kind = Some(AllocatorKind::Default);
}
if alloc_error_handler.is_some() {
self.cstore.alloc_error_handler_kind = Some(AllocatorKind::Global);
} else {
// The alloc crate provides a default allocation error handler if
// one isn't specified.
self.cstore.alloc_error_handler_kind = Some(AllocatorKind::Default);
}
}
fn inject_forced_externs(&mut self) {
for (name, entry) in self.sess.opts.externs.iter() {
if entry.force {
let name_interned = Symbol::intern(name);
if !self.used_extern_options.contains(&name_interned) {
self.resolve_crate(name_interned, DUMMY_SP, CrateDepKind::Explicit);
}
}
}
}
fn inject_dependency_if(
&self,
krate: CrateNum,
what: &str,
needs_dep: &dyn Fn(&CrateMetadata) -> bool,
) {
// don't perform this validation if the session has errors, as one of
// those errors may indicate a circular dependency which could cause
// this to stack overflow.
if self.sess.has_errors().is_some() {
return;
}
// Before we inject any dependencies, make sure we don't inject a
// circular dependency by validating that this crate doesn't
// transitively depend on any crates satisfying `needs_dep`.
for dep in self.cstore.crate_dependencies_in_reverse_postorder(krate) {
let data = self.cstore.get_crate_data(dep);
if needs_dep(&data) {
self.sess.emit_err(errors::NoTransitiveNeedsDep {
crate_name: self.cstore.get_crate_data(krate).name(),
needs_crate_name: what,
deps_crate_name: data.name(),
});
}
}
// All crates satisfying `needs_dep` do not explicitly depend on the
// crate provided for this compile, but in order for this compilation to
// be successfully linked we need to inject a dependency (to order the
// crates on the command line correctly).
for (cnum, data) in self.cstore.iter_crate_data() {
if needs_dep(data) {
info!("injecting a dep from {} to {}", cnum, krate);
data.add_dependency(krate);
}
}
}
fn report_unused_deps(&mut self, krate: &ast::Crate) {
// Make a point span rather than covering the whole file
let span = krate.spans.inner_span.shrink_to_lo();
// Complain about anything left over
for (name, entry) in self.sess.opts.externs.iter() {
if let ExternLocation::FoundInLibrarySearchDirectories = entry.location {
// Don't worry about pathless `--extern foo` sysroot references
continue;
}
if entry.nounused_dep || entry.force {
// We're not worried about this one
continue;
}
let name_interned = Symbol::intern(name);
if self.used_extern_options.contains(&name_interned) {
continue;
}
// Got a real unused --extern
if self.sess.opts.json_unused_externs.is_enabled() {
self.cstore.unused_externs.push(name_interned);
continue;
}
self.sess.parse_sess.buffer_lint(
lint::builtin::UNUSED_CRATE_DEPENDENCIES,
span,
ast::CRATE_NODE_ID,
format!(
"external crate `{}` unused in `{}`: remove the dependency or add `use {} as _;`",
name,
self.tcx.crate_name(LOCAL_CRATE),
name),
);
}
}
pub fn postprocess(&mut self, krate: &ast::Crate) {
self.inject_forced_externs();
self.inject_profiler_runtime(krate);
self.inject_allocator_crate(krate);
self.inject_panic_runtime(krate);
self.report_unused_deps(krate);
info!("{:?}", CrateDump(&self.cstore));
}
pub fn process_extern_crate(
&mut self,
item: &ast::Item,
def_id: LocalDefId,
definitions: &Definitions,
) -> Option<CrateNum> {
match item.kind {
ast::ItemKind::ExternCrate(orig_name) => {
debug!(
"resolving extern crate stmt. ident: {} orig_name: {:?}",
item.ident, orig_name
);
let name = match orig_name {
Some(orig_name) => {
validate_crate_name(self.sess, orig_name, Some(item.span));
orig_name
}
None => item.ident.name,
};
let dep_kind = if attr::contains_name(&item.attrs, sym::no_link) {
CrateDepKind::MacrosOnly
} else {
CrateDepKind::Explicit
};
let cnum = self.resolve_crate(name, item.span, dep_kind)?;
let path_len = definitions.def_path(def_id).data.len();
self.update_extern_crate(
cnum,
ExternCrate {
src: ExternCrateSource::Extern(def_id.to_def_id()),
span: item.span,
path_len,
dependency_of: LOCAL_CRATE,
},
);
Some(cnum)
}
_ => bug!(),
}
}
pub fn process_path_extern(&mut self, name: Symbol, span: Span) -> Option<CrateNum> {
let cnum = self.resolve_crate(name, span, CrateDepKind::Explicit)?;
self.update_extern_crate(
cnum,
ExternCrate {
src: ExternCrateSource::Path,
span,
// to have the least priority in `update_extern_crate`
path_len: usize::MAX,
dependency_of: LOCAL_CRATE,
},
);
Some(cnum)
}
pub fn maybe_process_path_extern(&mut self, name: Symbol) -> Option<CrateNum> {
self.maybe_resolve_crate(name, CrateDepKind::Explicit, None).ok()
}
}
fn global_allocator_spans(krate: &ast::Crate) -> Vec<Span> {
struct Finder {
name: Symbol,
spans: Vec<Span>,
}
impl<'ast> visit::Visitor<'ast> for Finder {
fn visit_item(&mut self, item: &'ast ast::Item) {
if item.ident.name == self.name
&& attr::contains_name(&item.attrs, sym::rustc_std_internal_symbol)
{
self.spans.push(item.span);
}
visit::walk_item(self, item)
}
}
let name = Symbol::intern(&global_fn_name(sym::alloc));
let mut f = Finder { name, spans: Vec::new() };
visit::walk_crate(&mut f, krate);
f.spans
}
fn alloc_error_handler_spans(krate: &ast::Crate) -> Vec<Span> {
struct Finder {
name: Symbol,
spans: Vec<Span>,
}
impl<'ast> visit::Visitor<'ast> for Finder {
fn visit_item(&mut self, item: &'ast ast::Item) {
if item.ident.name == self.name
&& attr::contains_name(&item.attrs, sym::rustc_std_internal_symbol)
{
self.spans.push(item.span);
}
visit::walk_item(self, item)
}
}
let name = Symbol::intern(alloc_error_handler_name(AllocatorKind::Global));
let mut f = Finder { name, spans: Vec::new() };
visit::walk_crate(&mut f, krate);
f.spans
}
// On Windows the compiler would sometimes intermittently fail to open the
// proc-macro DLL with `Error::LoadLibraryExW`. It is suspected that something in the
// system still holds a lock on the file, so we retry a few times before calling it
// an error.
fn load_dylib(path: &Path, max_attempts: usize) -> Result<libloading::Library, String> {
assert!(max_attempts > 0);
let mut last_error = None;
for attempt in 0..max_attempts {
match unsafe { libloading::Library::new(&path) } {
Ok(lib) => {
if attempt > 0 {
debug!(
"Loaded proc-macro `{}` after {} attempts.",
path.display(),
attempt + 1
);
}
return Ok(lib);
}
Err(err) => {
// Only try to recover from this specific error.
if !matches!(err, libloading::Error::LoadLibraryExW { .. }) {
return Err(err.to_string());
}
last_error = Some(err);
std::thread::sleep(Duration::from_millis(100));
debug!("Failed to load proc-macro `{}`. Retrying.", path.display());
}
}
}
debug!("Failed to load proc-macro `{}` even after {} attempts.", path.display(), max_attempts);
let last_error = last_error.unwrap();
let message = if let Some(src) = last_error.source() {
format!("{last_error} ({src}) (retried {max_attempts} times)")
} else {
format!("{last_error} (retried {max_attempts} times)")
};
Err(message)
}