path: root/compiler/rustc_middle/src/ty/query.rs

use crate::dep_graph;
use crate::infer::canonical::{self, Canonical};
use crate::lint::LintLevelMap;
use crate::metadata::ModChild;
use crate::middle::codegen_fn_attrs::CodegenFnAttrs;
use crate::middle::exported_symbols::{ExportedSymbol, SymbolExportInfo};
use crate::middle::lib_features::LibFeatures;
use crate::middle::privacy::AccessLevels;
use crate::middle::resolve_lifetime::{ObjectLifetimeDefault, Region, ResolveLifetimes};
use crate::middle::stability::{self, DeprecationEntry};
use crate::mir;
use crate::mir::interpret::GlobalId;
use crate::mir::interpret::{
    ConstValue, EvalToAllocationRawResult, EvalToConstValueResult, EvalToValTreeResult,
};
use crate::mir::interpret::{LitToConstError, LitToConstInput};
use crate::mir::mono::CodegenUnit;
use crate::thir;
use crate::traits::query::{
    CanonicalPredicateGoal, CanonicalProjectionGoal, CanonicalTyGoal,
    CanonicalTypeOpAscribeUserTypeGoal, CanonicalTypeOpEqGoal, CanonicalTypeOpNormalizeGoal,
    CanonicalTypeOpProvePredicateGoal, CanonicalTypeOpSubtypeGoal, NoSolution,
};
use crate::traits::query::{
    DropckConstraint, DropckOutlivesResult, MethodAutoderefStepsResult, NormalizationResult,
    OutlivesBound,
};
use crate::traits::specialization_graph;
use crate::traits::{self, ImplSource};
use crate::ty::fast_reject::SimplifiedType;
use crate::ty::layout::TyAndLayout;
use crate::ty::subst::{GenericArg, SubstsRef};
use crate::ty::util::AlwaysRequiresDrop;
use crate::ty::GeneratorDiagnosticData;
use crate::ty::{self, AdtSizedConstraint, CrateInherentImpls, ParamEnvAnd, Ty, TyCtxt};
use rustc_ast as ast;
use rustc_ast::expand::allocator::AllocatorKind;
use rustc_attr as attr;
use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap, FxIndexSet};
use rustc_data_structures::steal::Steal;
use rustc_data_structures::svh::Svh;
use rustc_data_structures::sync::Lrc;
use rustc_errors::ErrorGuaranteed;
use rustc_hir as hir;
use rustc_hir::def::DefKind;
use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, DefIdSet, LocalDefId};
use rustc_hir::lang_items::{LangItem, LanguageItems};
use rustc_hir::{Crate, ItemLocalId, TraitCandidate};
use rustc_index::{bit_set::FiniteBitSet, vec::IndexVec};
use rustc_session::config::{EntryFnType, OptLevel, OutputFilenames, SymbolManglingVersion};
use rustc_session::cstore::{CrateDepKind, CrateSource};
use rustc_session::cstore::{ExternCrate, ForeignModule, LinkagePreference, NativeLib};
use rustc_session::utils::NativeLibKind;
use rustc_session::Limits;
use rustc_span::symbol::Symbol;
use rustc_span::{Span, DUMMY_SP};
use rustc_target::abi;
use rustc_target::spec::PanicStrategy;
use std::ops::Deref;
use std::path::PathBuf;
use std::sync::Arc;

pub(crate) use rustc_query_system::query::QueryJobId;
use rustc_query_system::query::*;

#[derive(Copy, Clone)]
pub struct TyCtxtAt<'tcx> {
    pub tcx: TyCtxt<'tcx>,
    pub span: Span,
}

impl<'tcx> Deref for TyCtxtAt<'tcx> {
    type Target = TyCtxt<'tcx>;
    #[inline(always)]
    fn deref(&self) -> &Self::Target {
        &self.tcx
    }
}

#[derive(Copy, Clone)]
pub struct TyCtxtEnsure<'tcx> {
    pub tcx: TyCtxt<'tcx>,
}

impl<'tcx> TyCtxt<'tcx> {
    /// Returns a transparent wrapper for `TyCtxt`, which ensures queries
    /// are executed instead of just returning their results.
    #[inline(always)]
    pub fn ensure(self) -> TyCtxtEnsure<'tcx> {
        TyCtxtEnsure { tcx: self }
    }

    /// Returns a transparent wrapper for `TyCtxt` which uses
    /// `span` as the location of queries performed through it.
    #[inline(always)]
    pub fn at(self, span: Span) -> TyCtxtAt<'tcx> {
        TyCtxtAt { tcx: self, span }
    }

    pub fn try_mark_green(self, dep_node: &dep_graph::DepNode) -> bool {
        self.queries.try_mark_green(self, dep_node)
    }
}

/// Helper for `TyCtxtEnsure` to avoid a closure.
#[inline(always)]
fn noop<T>(_: &T) {}

/// Helper to ensure that queries only return `Copy` types.
#[inline(always)]
fn copy<T: Copy>(x: &T) -> T {
    *x
}

macro_rules! query_helper_param_ty {
    (DefId) => { impl IntoQueryParam<DefId> };
    ($K:ty) => { $K };
}

macro_rules! query_storage {
    ([][$K:ty, $V:ty]) => {
        <DefaultCacheSelector as CacheSelector<$K, $V>>::Cache
    };
    ([(storage $ty:ty) $($rest:tt)*][$K:ty, $V:ty]) => {
        <$ty as CacheSelector<$K, $V>>::Cache
    };
    ([$other:tt $($modifiers:tt)*][$($args:tt)*]) => {
        query_storage!([$($modifiers)*][$($args)*])
    };
}

macro_rules! separate_provide_extern_decl {
    ([][$name:ident]) => {
        ()
    };
    ([(separate_provide_extern) $($rest:tt)*][$name:ident]) => {
        for<'tcx> fn(
            TyCtxt<'tcx>,
            query_keys::$name<'tcx>,
        ) -> query_values::$name<'tcx>
    };
    ([$other:tt $($modifiers:tt)*][$($args:tt)*]) => {
        separate_provide_extern_decl!([$($modifiers)*][$($args)*])
    };
}

macro_rules! separate_provide_extern_default {
    ([][$name:ident]) => {
        ()
    };
    ([(separate_provide_extern) $($rest:tt)*][$name:ident]) => {
        |_, key| bug!(
            "`tcx.{}({:?})` unsupported by its crate; \
             perhaps the `{}` query was never assigned a provider function",
            stringify!($name),
            key,
            stringify!($name),
        )
    };
    ([$other:tt $($modifiers:tt)*][$($args:tt)*]) => {
        separate_provide_extern_default!([$($modifiers)*][$($args)*])
    };
}

macro_rules! opt_remap_env_constness {
    ([][$name:ident]) => {};
    ([(remap_env_constness) $($rest:tt)*][$name:ident]) => {
        let $name = $name.without_const();
    };
    ([$other:tt $($modifiers:tt)*][$name:ident]) => {
        opt_remap_env_constness!([$($modifiers)*][$name])
    };
}

macro_rules! define_callbacks {
    (<$tcx:tt>
     $($(#[$attr:meta])*
        [$($modifiers:tt)*] fn $name:ident($($K:tt)*) -> $V:ty,)*) => {

        // HACK(eddyb) this is like the `impl QueryConfig for queries::$name`
        // below, but using type aliases instead of associated types, to bypass
        // the limitations around normalizing under HRTB - for example, this:
        // `for<'tcx> fn(...) -> <queries::$name<'tcx> as QueryConfig<TyCtxt<'tcx>>>::Value`
        // doesn't currently normalize to `for<'tcx> fn(...) -> query_values::$name<'tcx>`.
        // This is primarily used by the `provide!` macro in `rustc_metadata`.
        #[allow(nonstandard_style, unused_lifetimes)]
        pub mod query_keys {
            use super::*;

            $(pub type $name<$tcx> = $($K)*;)*
        }
        #[allow(nonstandard_style, unused_lifetimes)]
        pub mod query_values {
            use super::*;

            $(pub type $name<$tcx> = $V;)*
        }
        #[allow(nonstandard_style, unused_lifetimes)]
        pub mod query_storage {
            use super::*;

            $(pub type $name<$tcx> = query_storage!([$($modifiers)*][$($K)*, $V]);)*
        }
        #[allow(nonstandard_style, unused_lifetimes)]
        pub mod query_stored {
            use super::*;

            $(pub type $name<$tcx> = <query_storage::$name<$tcx> as QueryStorage>::Stored;)*
        }

        #[derive(Default)]
        pub struct QueryCaches<$tcx> {
            $($(#[$attr])* pub $name: query_storage::$name<$tcx>,)*
        }

        impl<$tcx> TyCtxtEnsure<$tcx> {
            $($(#[$attr])*
            #[inline(always)]
            pub fn $name(self, key: query_helper_param_ty!($($K)*)) {
                let key = key.into_query_param();
                opt_remap_env_constness!([$($modifiers)*][key]);

                let cached = try_get_cached(self.tcx, &self.tcx.query_caches.$name, &key, noop);

                match cached {
                    Ok(()) => return,
                    Err(()) => (),
                }

                self.tcx.queries.$name(self.tcx, DUMMY_SP, key, QueryMode::Ensure);
            })*
        }

        impl<$tcx> TyCtxt<$tcx> {
            $($(#[$attr])*
            #[inline(always)]
            #[must_use]
            pub fn $name(self, key: query_helper_param_ty!($($K)*)) -> query_stored::$name<$tcx>
            {
                self.at(DUMMY_SP).$name(key)
            })*
        }

        impl<$tcx> TyCtxtAt<$tcx> {
            $($(#[$attr])*
            #[inline(always)]
            pub fn $name(self, key: query_helper_param_ty!($($K)*)) -> query_stored::$name<$tcx>
            {
                let key = key.into_query_param();
                opt_remap_env_constness!([$($modifiers)*][key]);

                let cached = try_get_cached(self.tcx, &self.tcx.query_caches.$name, &key, copy);

                match cached {
                    Ok(value) => return value,
                    Err(()) => (),
                }

                self.tcx.queries.$name(self.tcx, self.span, key, QueryMode::Get).unwrap()
            })*
        }

        pub struct Providers {
            $(pub $name: for<'tcx> fn(
                TyCtxt<'tcx>,
                query_keys::$name<'tcx>,
            ) -> query_values::$name<'tcx>,)*
        }

        pub struct ExternProviders {
            $(pub $name: separate_provide_extern_decl!([$($modifiers)*][$name]),)*
        }

        impl Default for Providers {
            fn default() -> Self {
                Providers {
                    $($name: |_, key| bug!(
                        "`tcx.{}({:?})` unsupported by its crate; \
                         perhaps the `{}` query was never assigned a provider function",
                        stringify!($name),
                        key,
                        stringify!($name),
                    ),)*
                }
            }
        }

        impl Default for ExternProviders {
            fn default() -> Self {
                ExternProviders {
                    $($name: separate_provide_extern_default!([$($modifiers)*][$name]),)*
                }
            }
        }

        impl Copy for Providers {}
        impl Clone for Providers {
            fn clone(&self) -> Self { *self }
        }

        impl Copy for ExternProviders {}
        impl Clone for ExternProviders {
            fn clone(&self) -> Self { *self }
        }

        pub trait QueryEngine<'tcx>: rustc_data_structures::sync::Sync {
            fn as_any(&'tcx self) -> &'tcx dyn std::any::Any;

            fn try_mark_green(&'tcx self, tcx: TyCtxt<'tcx>, dep_node: &dep_graph::DepNode) -> bool;

            $($(#[$attr])*
            fn $name(
                &'tcx self,
                tcx: TyCtxt<$tcx>,
                span: Span,
                key: query_keys::$name<$tcx>,
                mode: QueryMode,
            ) -> Option<query_stored::$name<$tcx>>;)*
        }
    };
}

// Each of these queries corresponds to a function pointer field in the
// `Providers` struct for requesting a value of that type, and a method
// on `tcx: TyCtxt` (and `tcx.at(span)`) for doing that request in a way
// which memoizes and does dep-graph tracking, wrapping around the actual
// `Providers` that the driver creates (using several `rustc_*` crates).
//
// The result type of each query must implement `Clone`, and additionally
// `ty::query::values::Value`, which produces an appropriate placeholder
// (error) value if the query resulted in a query cycle.
// Queries marked with `fatal_cycle` do not need the latter implementation,
// as they will raise an fatal error on query cycles instead.

rustc_query_append! { [define_callbacks!][<'tcx>] }

mod sealed {
    use super::{DefId, LocalDefId};

    /// An analogue of the `Into` trait that's intended only for query parameters.
    ///
    /// This exists to allow queries to accept either `DefId` or `LocalDefId` while requiring that the
    /// user call `to_def_id` to convert between them everywhere else.
    pub trait IntoQueryParam<P> {
        fn into_query_param(self) -> P;
    }

    impl<P> IntoQueryParam<P> for P {
        #[inline(always)]
        fn into_query_param(self) -> P {
            self
        }
    }

    impl<'a, P: Copy> IntoQueryParam<P> for &'a P {
        #[inline(always)]
        fn into_query_param(self) -> P {
            *self
        }
    }

    impl IntoQueryParam<DefId> for LocalDefId {
        #[inline(always)]
        fn into_query_param(self) -> DefId {
            self.to_def_id()
        }
    }
}

use sealed::IntoQueryParam;

impl<'tcx> TyCtxt<'tcx> {
    pub fn def_kind(self, def_id: impl IntoQueryParam<DefId>) -> DefKind {
        let def_id = def_id.into_query_param();
        self.opt_def_kind(def_id)
            .unwrap_or_else(|| bug!("def_kind: unsupported node: {:?}", def_id))
    }
}

impl<'tcx> TyCtxtAt<'tcx> {
    pub fn def_kind(self, def_id: impl IntoQueryParam<DefId>) -> DefKind {
        let def_id = def_id.into_query_param();
        self.opt_def_kind(def_id)
            .unwrap_or_else(|| bug!("def_kind: unsupported node: {:?}", def_id))
    }
}