cstore_impl.rs

use crate::creader::{CStore, LoadedMacro};
use crate::foreign_modules;
use crate::native_libs;

use rustc_ast as ast;
use rustc_data_structures::stable_map::FxHashMap;
use rustc_hir::def::{CtorKind, DefKind};
use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, CRATE_DEF_INDEX, LOCAL_CRATE};
use rustc_hir::definitions::{DefKey, DefPath, DefPathHash};
use rustc_middle::hir::exports::Export;
use rustc_middle::middle::exported_symbols::ExportedSymbol;
use rustc_middle::middle::stability::DeprecationEntry;
use rustc_middle::ty::query::{ExternProviders, Providers};
use rustc_middle::ty::{self, TyCtxt, Visibility};
use rustc_session::cstore::{CrateSource, CrateStore, ForeignModule};
use rustc_session::utils::NativeLibKind;
use rustc_session::{Session, StableCrateId};
use rustc_span::hygiene::{ExpnHash, ExpnId};
use rustc_span::source_map::{Span, Spanned};
use rustc_span::symbol::{kw, Symbol};

use rustc_data_structures::sync::Lrc;
use smallvec::SmallVec;
use std::any::Any;

macro_rules! provide {
    (<$lt:tt> $tcx:ident, $def_id:ident, $other:ident, $cdata:ident,
      $($name:ident => $compute:block)*) => {
        pub fn provide_extern(providers: &mut ExternProviders) {
            $(fn $name<$lt>(
                $tcx: TyCtxt<$lt>,
                def_id_arg: ty::query::query_keys::$name<$lt>,
            ) -> ty::query::query_values::$name<$lt> {
                let _prof_timer =
                    $tcx.prof.generic_activity(concat!("metadata_decode_entry_", stringify!($name)));

                #[allow(unused_variables)]
                let ($def_id, $other) = def_id_arg.into_args();
                assert!(!$def_id.is_local());

                // External query providers call `crate_hash` in order to register a dependency
                // on the crate metadata. The exception is `crate_hash` itself, which obviously
                // doesn't need to do this (and can't, as it would cause a query cycle).
                use rustc_middle::dep_graph::DepKind;
                if DepKind::$name != DepKind::crate_hash && $tcx.dep_graph.is_fully_enabled() {
                    $tcx.ensure().crate_hash($def_id.krate);
                }

                let $cdata = CStore::from_tcx($tcx).get_crate_data($def_id.krate);

                $compute
            })*

            *providers = ExternProviders {
                $($name,)*
                ..*providers
            };
        }
    }
}

// small trait to work around different signature queries all being defined via
// the macro above.
trait IntoArgs {
    fn into_args(self) -> (DefId, DefId);
}

impl IntoArgs for DefId {
    fn into_args(self) -> (DefId, DefId) {
        (self, self)
    }
}

impl IntoArgs for CrateNum {
    fn into_args(self) -> (DefId, DefId) {
        (self.as_def_id(), self.as_def_id())
    }
}

impl IntoArgs for (CrateNum, DefId) {
    fn into_args(self) -> (DefId, DefId) {
        (self.0.as_def_id(), self.1)
    }
}

impl<'tcx> IntoArgs for ty::InstanceDef<'tcx> {
    fn into_args(self) -> (DefId, DefId) {
        (self.def_id(), self.def_id())
    }
}

provide! { <'tcx> tcx, def_id, other, cdata,
    type_of => { cdata.get_type(def_id.index, tcx) }
    generics_of => { cdata.get_generics(def_id.index, tcx.sess) }
    explicit_predicates_of => { cdata.get_explicit_predicates(def_id.index, tcx) }
    inferred_outlives_of => { cdata.get_inferred_outlives(def_id.index, tcx) }
    super_predicates_of => { cdata.get_super_predicates(def_id.index, tcx) }
    explicit_item_bounds => { cdata.get_explicit_item_bounds(def_id.index, tcx) }
    trait_def => { cdata.get_trait_def(def_id.index, tcx.sess) }
    adt_def => { cdata.get_adt_def(def_id.index, tcx) }
    adt_destructor => {
        let _ = cdata;
        tcx.calculate_dtor(def_id, |_,_| Ok(()))
    }
    variances_of => { tcx.arena.alloc_from_iter(cdata.get_item_variances(def_id.index)) }
    associated_item_def_ids => {
        let mut result = SmallVec::<[_; 8]>::new();
        cdata.each_child_of_item(def_id.index,
          |child| result.push(child.res.def_id()), tcx.sess);
        tcx.arena.alloc_slice(&result)
    }
    associated_item => { cdata.get_associated_item(def_id.index, tcx.sess) }
    impl_trait_ref => { cdata.get_impl_trait(def_id.index, tcx) }
    impl_polarity => { cdata.get_impl_polarity(def_id.index) }
    coerce_unsized_info => {
        cdata.get_coerce_unsized_info(def_id.index).unwrap_or_else(|| {
            bug!("coerce_unsized_info: `{:?}` is missing its info", def_id);
        })
    }
    optimized_mir => { tcx.arena.alloc(cdata.get_optimized_mir(tcx, def_id.index)) }
    mir_for_ctfe => { tcx.arena.alloc(cdata.get_mir_for_ctfe(tcx, def_id.index)) }
    promoted_mir => { tcx.arena.alloc(cdata.get_promoted_mir(tcx, def_id.index)) }
    thir_abstract_const => { cdata.get_thir_abstract_const(tcx, def_id.index) }
    unused_generic_params => { cdata.get_unused_generic_params(def_id.index) }
    const_param_default => { tcx.mk_const(cdata.get_const_param_default(tcx, def_id.index)) }
    mir_const_qualif => { cdata.mir_const_qualif(def_id.index) }
    fn_sig => { cdata.fn_sig(def_id.index, tcx) }
    inherent_impls => { cdata.get_inherent_implementations_for_type(tcx, def_id.index) }
    is_const_fn_raw => { cdata.is_const_fn_raw(def_id.index) }
    asyncness => { cdata.asyncness(def_id.index) }
    is_foreign_item => { cdata.is_foreign_item(def_id.index) }
    static_mutability => { cdata.static_mutability(def_id.index) }
    generator_kind => { cdata.generator_kind(def_id.index) }
    opt_def_kind => { Some(cdata.def_kind(def_id.index)) }
    def_span => { cdata.get_span(def_id.index, &tcx.sess) }
    def_ident => {
        cdata.try_item_ident(def_id.index, &tcx.sess).ok()
    }
    lookup_stability => {
        cdata.get_stability(def_id.index).map(|s| tcx.intern_stability(s))
    }
    lookup_const_stability => {
        cdata.get_const_stability(def_id.index).map(|s| tcx.intern_const_stability(s))
    }
    lookup_deprecation_entry => {
        cdata.get_deprecation(def_id.index).map(DeprecationEntry::external)
    }
    item_attrs => { tcx.arena.alloc_from_iter(
        cdata.get_item_attrs(def_id.index, tcx.sess)
    ) }
    fn_arg_names => { cdata.get_fn_param_names(tcx, def_id.index) }
    rendered_const => { cdata.get_rendered_const(def_id.index) }
    impl_parent => { cdata.get_parent_impl(def_id.index) }
    trait_of_item => { cdata.get_trait_of_item(def_id.index) }
    is_mir_available => { cdata.is_item_mir_available(def_id.index) }
    is_ctfe_mir_available => { cdata.is_ctfe_mir_available(def_id.index) }

    dylib_dependency_formats => { cdata.get_dylib_dependency_formats(tcx) }
    is_private_dep => { cdata.private_dep }
    is_panic_runtime => { cdata.root.panic_runtime }
    is_compiler_builtins => { cdata.root.compiler_builtins }
    has_global_allocator => { cdata.root.has_global_allocator }
    has_panic_handler => { cdata.root.has_panic_handler }
    is_profiler_runtime => { cdata.root.profiler_runtime }
    panic_strategy => { cdata.root.panic_strategy }
    panic_in_drop_strategy => { cdata.root.panic_in_drop_strategy }
    extern_crate => {
        let r = *cdata.extern_crate.lock();
        r.map(|c| &*tcx.arena.alloc(c))
    }
    is_no_builtins => { cdata.root.no_builtins }
    symbol_mangling_version => { cdata.root.symbol_mangling_version }
    impl_defaultness => { cdata.get_impl_defaultness(def_id.index) }
    impl_constness => { cdata.get_impl_constness(def_id.index) }
    reachable_non_generics => {
        let reachable_non_generics = tcx
            .exported_symbols(cdata.cnum)
            .iter()
            .filter_map(|&(exported_symbol, export_level)| {
                if let ExportedSymbol::NonGeneric(def_id) = exported_symbol {
                    Some((def_id, export_level))
                } else {
                    None
                }
            })
            .collect();

        reachable_non_generics
    }
    native_libraries => { Lrc::new(cdata.get_native_libraries(tcx.sess)) }
    foreign_modules => { cdata.get_foreign_modules(tcx) }
    crate_hash => { cdata.root.hash }
    crate_host_hash => { cdata.host_hash }
    crate_name => { cdata.root.name }

    extra_filename => { cdata.root.extra_filename.clone() }

    implementations_of_trait => {
        cdata.get_implementations_for_trait(tcx, Some(other))
    }

    all_trait_implementations => {
        cdata.get_implementations_for_trait(tcx, None)
    }

    visibility => { cdata.get_visibility(def_id.index) }
    dep_kind => {
        let r = *cdata.dep_kind.lock();
        r
    }
    item_children => {
        let mut result = SmallVec::<[_; 8]>::new();
        cdata.each_child_of_item(def_id.index, |child| result.push(child), tcx.sess);
        tcx.arena.alloc_slice(&result)
    }
    defined_lib_features => { cdata.get_lib_features(tcx) }
    defined_lang_items => { cdata.get_lang_items(tcx) }
    diagnostic_items => { cdata.get_diagnostic_items() }
    missing_lang_items => { cdata.get_missing_lang_items(tcx) }

    missing_extern_crate_item => {
        let r = matches!(*cdata.extern_crate.borrow(), Some(extern_crate) if !extern_crate.is_direct());
        r
    }

    used_crate_source => { Lrc::new(cdata.source.clone()) }

    exported_symbols => {
        let syms = cdata.exported_symbols(tcx);

        // FIXME rust-lang/rust#64319, rust-lang/rust#64872: We want
        // to block export of generics from dylibs, but we must fix
        // rust-lang/rust#65890 before we can do that robustly.

        syms
    }

    crate_extern_paths => { cdata.source().paths().cloned().collect() }
    expn_that_defined => { cdata.get_expn_that_defined(def_id.index, tcx.sess) }
}

pub fn provide(providers: &mut Providers) {
    // FIXME(#44234) - almost all of these queries have no sub-queries and
    // therefore no actual inputs, they're just reading tables calculated in
    // resolve! Does this work? Unsure! That's what the issue is about
    *providers = Providers {
        allocator_kind: |tcx, ()| CStore::from_tcx(tcx).allocator_kind(),
        is_dllimport_foreign_item: |tcx, id| match tcx.native_library_kind(id) {
            Some(
                NativeLibKind::Dylib { .. } | NativeLibKind::RawDylib | NativeLibKind::Unspecified,
            ) => true,
            _ => false,
        },
        is_statically_included_foreign_item: |tcx, id| {
            matches!(tcx.native_library_kind(id), Some(NativeLibKind::Static { .. }))
        },
        is_private_dep: |_tcx, cnum| {
            assert_eq!(cnum, LOCAL_CRATE);
            false
        },
        native_library_kind: |tcx, id| {
            tcx.native_libraries(id.krate)
                .iter()
                .filter(|lib| native_libs::relevant_lib(&tcx.sess, lib))
                .find(|lib| {
                    let fm_id = match lib.foreign_module {
                        Some(id) => id,
                        None => return false,
                    };
                    let map = tcx.foreign_modules(id.krate);
                    map.get(&fm_id)
                        .expect("failed to find foreign module")
                        .foreign_items
                        .contains(&id)
                })
                .map(|l| l.kind)
        },
        native_libraries: |tcx, cnum| {
            assert_eq!(cnum, LOCAL_CRATE);
            Lrc::new(native_libs::collect(tcx))
        },
        foreign_modules: |tcx, cnum| {
            assert_eq!(cnum, LOCAL_CRATE);
            let modules: FxHashMap<DefId, ForeignModule> =
                foreign_modules::collect(tcx).into_iter().map(|m| (m.def_id, m)).collect();
            Lrc::new(modules)
        },

        // Returns a map from a sufficiently visible external item (i.e., an
        // external item that is visible from at least one local module) to a
        // sufficiently visible parent (considering modules that re-export the
        // external item to be parents).
        visible_parents_map: |tcx, ()| {
            use rustc_data_structures::fx::FxHashSet;
            use std::collections::VecDeque;

            let mut visible_parents_map: DefIdMap<SmallVec<[DefId; 4]>> = DefIdMap::default();

            // Issue 46112: We want the map to prefer the shortest
            // paths when reporting the path to an item. Therefore we
            // build up the map via a breadth-first search (BFS),
            // which naturally yields minimal-length paths.
            //
            // Note that it needs to be a BFS over the whole forest of
            // crates, not just each individual crate; otherwise you
            // only get paths that are locally minimal with respect to
            // whatever crate we happened to encounter first in this
            // traversal, but not globally minimal across all crates.
            let mut bfs_queue = VecDeque::default();

            bfs_queue.extend(
                tcx.crates(())
                    .into_iter()
                    // Ignore crates without a corresponding local `extern crate` item.
                    .filter(|cnum| !tcx.missing_extern_crate_item(**cnum))
                    .map(|cnum| DefId { krate: *cnum, index: CRATE_DEF_INDEX }),
            );

            // Iterate over graph using BFS.
            // Filter out any non-public items.
            while let Some(parent) = bfs_queue.pop_front() {
                for child in tcx
                    .item_children(parent)
                    .iter()
                    .filter(|child| child.vis.is_public())
                    .filter_map(|child| child.res.opt_def_id())
                {
                    visible_parents_map
                        .entry(child)
                        .or_insert_with(|| {
                            // If we encounter node the first time
                            // add it to queue for next iterations
                            bfs_queue.push_back(child);
                            Default::default()
                        })
                        .push(parent);
                }
            }

            // Iterate over parents vector to remove duplicate elements
            // while preserving order
            let mut dedup_set = FxHashSet::default();
            for (_, parents) in &mut visible_parents_map {
                parents.retain(|parent| dedup_set.insert(*parent));

                // Reuse hashset allocation.
                dedup_set.clear();
            }

            visible_parents_map
        },
        best_visible_parent: |tcx, child| {
            // Use `min_by_key` because it returns
            // first match in case keys are equal
            tcx.visible_parents_map(())
                .get(&child)?
                .into_iter()
                .min_by_key(|parent| {
                    // If this is just regular export in another module, assign it a neutral score.
                    let mut score = 0;

                    // If child and parent are local, we prefer them
                    if child.is_local() && parent.is_local() {
                        score += 1;
                    }

                    // Even if child and parent are local, if parent is `#[doc(hidden)]`
                    // We reduce their score to avoid showing items not popping in documentation.
                    if ast::attr::is_doc_hidden(tcx.item_attrs(**parent)) {
                        score -= 2;
                    }

                    // If parent identifier is _ we prefer it only as last resort if other items are not available
                    if let Some(ident) = tcx.def_ident(**parent) {
                        if ident.name == kw::Underscore {
                            score -= 3;
                        }
                    }

                    -score
                })
                .map(ToOwned::to_owned)
        },
        dependency_formats: |tcx, ()| Lrc::new(crate::dependency_format::calculate(tcx)),
        has_global_allocator: |tcx, cnum| {
            assert_eq!(cnum, LOCAL_CRATE);
            CStore::from_tcx(tcx).has_global_allocator()
        },
        postorder_cnums: |tcx, ()| {
            tcx.arena
                .alloc_slice(&CStore::from_tcx(tcx).crate_dependencies_in_postorder(LOCAL_CRATE))
        },
        crates: |tcx, ()| tcx.arena.alloc_slice(&CStore::from_tcx(tcx).crates_untracked()),

        ..*providers
    };
}

impl CStore {
    pub fn struct_field_names_untracked(&self, def: DefId, sess: &Session) -> Vec<Spanned<Symbol>> {
        self.get_crate_data(def.krate).get_struct_field_names(def.index, sess)
    }

    pub fn struct_field_visibilities_untracked(&self, def: DefId) -> Vec<Visibility> {
        self.get_crate_data(def.krate).get_struct_field_visibilities(def.index)
    }

    pub fn ctor_def_id_and_kind_untracked(&self, def: DefId) -> Option<(DefId, CtorKind)> {
        self.get_crate_data(def.krate).get_ctor_def_id(def.index).map(|ctor_def_id| {
            (ctor_def_id, self.get_crate_data(def.krate).get_ctor_kind(def.index))
        })
    }

    pub fn visibility_untracked(&self, def: DefId) -> Visibility {
        self.get_crate_data(def.krate).get_visibility(def.index)
    }

    pub fn item_children_untracked(&self, def_id: DefId, sess: &Session) -> Vec<Export> {
        let mut result = vec![];
        self.get_crate_data(def_id.krate).each_child_of_item(
            def_id.index,
            |child| result.push(child),
            sess,
        );
        result
    }

    pub fn load_macro_untracked(&self, id: DefId, sess: &Session) -> LoadedMacro {
        let _prof_timer = sess.prof.generic_activity("metadata_load_macro");

        let data = self.get_crate_data(id.krate);
        if data.root.is_proc_macro_crate() {
            return LoadedMacro::ProcMacro(data.load_proc_macro(id.index, sess));
        }

        let span = data.get_span(id.index, sess);

        let attrs = data.get_item_attrs(id.index, sess).collect();

        let ident = data.item_ident(id.index, sess);

        LoadedMacro::MacroDef(
            ast::Item {
                ident,
                id: ast::DUMMY_NODE_ID,
                span,
                attrs,
                kind: ast::ItemKind::MacroDef(data.get_macro(id.index, sess)),
                vis: ast::Visibility {
                    span: span.shrink_to_lo(),
                    kind: ast::VisibilityKind::Inherited,
                    tokens: None,
                },
                tokens: None,
            },
            data.root.edition,
        )
    }

    pub fn associated_item_cloned_untracked(&self, def: DefId, sess: &Session) -> ty::AssocItem {
        self.get_crate_data(def.krate).get_associated_item(def.index, sess)
    }

    pub fn crate_source_untracked(&self, cnum: CrateNum) -> CrateSource {
        self.get_crate_data(cnum).source.clone()
    }

    pub fn get_span_untracked(&self, def_id: DefId, sess: &Session) -> Span {
        self.get_crate_data(def_id.krate).get_span(def_id.index, sess)
    }

    pub fn def_kind(&self, def: DefId) -> DefKind {
        self.get_crate_data(def.krate).def_kind(def.index)
    }

    pub fn crates_untracked(&self) -> Vec<CrateNum> {
        let mut result = vec![];
        self.iter_crate_data(|cnum, _| result.push(cnum));
        result
    }

    pub fn item_generics_num_lifetimes(&self, def_id: DefId, sess: &Session) -> usize {
        self.get_crate_data(def_id.krate).get_generics(def_id.index, sess).own_counts().lifetimes
    }

    pub fn module_expansion_untracked(&self, def_id: DefId, sess: &Session) -> ExpnId {
        self.get_crate_data(def_id.krate).module_expansion(def_id.index, sess)
    }

    /// Only public-facing way to traverse all the definitions in a non-local crate.
    /// Critically useful for this third-party project: <https://github.com/hacspec/hacspec>.
    /// See <https://github.com/rust-lang/rust/pull/85889> for context.
    pub fn num_def_ids_untracked(&self, cnum: CrateNum) -> usize {
        self.get_crate_data(cnum).num_def_ids()
    }

    pub fn item_attrs(&self, def_id: DefId, sess: &Session) -> Vec<ast::Attribute> {
        self.get_crate_data(def_id.krate).get_item_attrs(def_id.index, sess).collect()
    }

    pub fn get_proc_macro_quoted_span_untracked(
        &self,
        cnum: CrateNum,
        id: usize,
        sess: &Session,
    ) -> Span {
        self.get_crate_data(cnum).get_proc_macro_quoted_span(id, sess)
    }
}

impl CrateStore for CStore {
    fn as_any(&self) -> &dyn Any {
        self
    }

    fn crate_name(&self, cnum: CrateNum) -> Symbol {
        self.get_crate_data(cnum).root.name
    }

    fn stable_crate_id(&self, cnum: CrateNum) -> StableCrateId {
        self.get_crate_data(cnum).root.stable_crate_id
    }

    fn stable_crate_id_to_crate_num(&self, stable_crate_id: StableCrateId) -> CrateNum {
        self.stable_crate_ids[&stable_crate_id]
    }

    /// Returns the `DefKey` for a given `DefId`. This indicates the
    /// parent `DefId` as well as some idea of what kind of data the
    /// `DefId` refers to.
    fn def_key(&self, def: DefId) -> DefKey {
        self.get_crate_data(def.krate).def_key(def.index)
    }

    fn def_path(&self, def: DefId) -> DefPath {
        self.get_crate_data(def.krate).def_path(def.index)
    }

    fn def_path_hash(&self, def: DefId) -> DefPathHash {
        self.get_crate_data(def.krate).def_path_hash(def.index)
    }

    fn def_path_hash_to_def_id(&self, cnum: CrateNum, hash: DefPathHash) -> DefId {
        let def_index = self.get_crate_data(cnum).def_path_hash_to_def_index(hash);
        DefId { krate: cnum, index: def_index }
    }

    fn expn_hash_to_expn_id(
        &self,
        sess: &Session,
        cnum: CrateNum,
        index_guess: u32,
        hash: ExpnHash,
    ) -> ExpnId {
        self.get_crate_data(cnum).expn_hash_to_expn_id(sess, index_guess, hash)
    }
}