compiler/rustc_middle/src/dep_graph/mod.rs

use std::panic;

use rustc_data_structures::profiling::SelfProfilerRef;
use rustc_data_structures::sync::DynSync;
use rustc_query_system::ich::StableHashingContext;
use rustc_session::Session;
use tracing::instrument;

pub use self::dep_node::{
    DepKind, DepNode, DepNodeExt, DepNodeKey, WorkProductId, dep_kind_from_label, dep_kinds,
    label_strs,
};
pub use self::graph::{
    DepGraphData, DepNodeIndex, TaskDepsRef, WorkProduct, WorkProductMap, hash_result,
};
use self::graph::{MarkFrame, print_markframe_trace};
pub use self::query::DepGraphQuery;
pub use self::serialized::{SerializedDepGraph, SerializedDepNodeIndex};
pub use crate::dep_graph::debug::{DepNodeFilter, EdgeFilter};
use crate::ty::print::with_reduced_queries;
use crate::ty::{self, TyCtxt};

mod debug;
pub mod dep_node;
mod dep_node_key;
mod edges;
mod graph;
mod query;
mod serialized;

pub trait DepContext: Copy {
    type Deps: Deps;

    /// Create a hashing context for hashing new results.
    fn with_stable_hashing_context<R>(self, f: impl FnOnce(StableHashingContext<'_>) -> R) -> R;

    /// Access the DepGraph.
    fn dep_graph(&self) -> &graph::DepGraph<Self::Deps>;

    /// Access the profiler.
    fn profiler(&self) -> &SelfProfilerRef;

    /// Access the compiler session.
    fn sess(&self) -> &Session;

    fn dep_kind_vtable(&self, dep_node: DepKind) -> &dep_node::DepKindVTable<Self>;

    #[inline(always)]
    fn fingerprint_style(self, kind: DepKind) -> FingerprintStyle {
        self.dep_kind_vtable(kind).fingerprint_style
    }

    #[inline(always)]
    /// Return whether this kind always require evaluation.
    fn is_eval_always(self, kind: DepKind) -> bool {
        self.dep_kind_vtable(kind).is_eval_always
    }

    /// Try to force a dep node to execute and see if it's green.
    ///
    /// Returns true if the query has actually been forced. It is valid that a query
    /// fails to be forced, e.g. when the query key cannot be reconstructed from the
    /// dep-node or when the query kind outright does not support it.
    #[inline]
    #[instrument(skip(self, frame), level = "debug")]
    fn try_force_from_dep_node(
        self,
        dep_node: DepNode,
        prev_index: SerializedDepNodeIndex,
        frame: &MarkFrame<'_>,
    ) -> bool {
        if let Some(force_fn) = self.dep_kind_vtable(dep_node.kind).force_from_dep_node {
            match panic::catch_unwind(panic::AssertUnwindSafe(|| {
                force_fn(self, dep_node, prev_index)
            })) {
                Err(value) => {
                    if !value.is::<rustc_errors::FatalErrorMarker>() {
                        print_markframe_trace(self.dep_graph(), frame);
                    }
                    panic::resume_unwind(value)
                }
                Ok(query_has_been_forced) => query_has_been_forced,
            }
        } else {
            false
        }
    }

    /// Load data from the on-disk cache.
    fn try_load_from_on_disk_cache(self, dep_node: &DepNode) {
        if let Some(try_load_fn) = self.dep_kind_vtable(dep_node.kind).try_load_from_on_disk_cache {
            try_load_fn(self, *dep_node)
        }
    }

    fn with_reduced_queries<T>(self, _: impl FnOnce() -> T) -> T;
}

pub trait Deps: DynSync {
    /// Execute the operation with provided dependencies.
    fn with_deps<OP, R>(deps: TaskDepsRef<'_>, op: OP) -> R
    where
        OP: FnOnce() -> R;

    /// Access dependencies from current implicit context.
    fn read_deps<OP>(op: OP)
    where
        OP: for<'a> FnOnce(TaskDepsRef<'a>);

    fn name(dep_kind: DepKind) -> &'static str;

    /// We use this for most things when incr. comp. is turned off.
    const DEP_KIND_NULL: DepKind;

    /// We use this to create a forever-red node.
    const DEP_KIND_RED: DepKind;

    /// We use this to create a side effect node.
    const DEP_KIND_SIDE_EFFECT: DepKind;

    /// We use this to create the anon node with zero dependencies.
    const DEP_KIND_ANON_ZERO_DEPS: DepKind;

    /// This is the highest value a `DepKind` can have. It's used during encoding to
    /// pack information into the unused bits.
    const DEP_KIND_MAX: u16;
}

pub trait HasDepContext: Copy {
    type Deps: self::Deps;
    type DepContext: self::DepContext<Deps = Self::Deps>;

    fn dep_context(&self) -> &Self::DepContext;
}

impl<T: DepContext> HasDepContext for T {
    type Deps = T::Deps;
    type DepContext = Self;

    fn dep_context(&self) -> &Self::DepContext {
        self
    }
}

impl<T: HasDepContext, Q: Copy> HasDepContext for (T, Q) {
    type Deps = T::Deps;
    type DepContext = T::DepContext;

    fn dep_context(&self) -> &Self::DepContext {
        self.0.dep_context()
    }
}

/// Describes the contents of the fingerprint generated by a given query.
///
/// This is mainly for determining whether and how we can reconstruct a key
/// from the fingerprint.
#[derive(Debug, PartialEq, Eq, Copy, Clone)]
pub enum FingerprintStyle {
    /// The fingerprint is actually a DefPathHash.
    DefPathHash,
    /// The fingerprint is actually a HirId.
    HirId,
    /// Query key was `()` or equivalent, so fingerprint is just zero.
    Unit,
    /// The fingerprint is an opaque hash, and a key cannot be reconstructed from it.
    Opaque,
}

impl FingerprintStyle {
    #[inline]
    pub const fn reconstructible(self) -> bool {
        match self {
            FingerprintStyle::DefPathHash | FingerprintStyle::Unit | FingerprintStyle::HirId => {
                true
            }
            FingerprintStyle::Opaque => false,
        }
    }
}

pub type DepGraph = graph::DepGraph<DepsType>;

pub type DepKindVTable<'tcx> = dep_node::DepKindVTable<TyCtxt<'tcx>>;

pub struct DepsType;

impl Deps for DepsType {
    fn with_deps<OP, R>(task_deps: TaskDepsRef<'_>, op: OP) -> R
    where
        OP: FnOnce() -> R,
    {
        ty::tls::with_context(|icx| {
            let icx = ty::tls::ImplicitCtxt { task_deps, ..icx.clone() };

            ty::tls::enter_context(&icx, op)
        })
    }

    fn read_deps<OP>(op: OP)
    where
        OP: for<'a> FnOnce(TaskDepsRef<'a>),
    {
        ty::tls::with_context_opt(|icx| {
            let Some(icx) = icx else { return };
            op(icx.task_deps)
        })
    }

    fn name(dep_kind: DepKind) -> &'static str {
        dep_node::DEP_KIND_NAMES[dep_kind.as_usize()]
    }

    const DEP_KIND_NULL: DepKind = dep_kinds::Null;
    const DEP_KIND_RED: DepKind = dep_kinds::Red;
    const DEP_KIND_SIDE_EFFECT: DepKind = dep_kinds::SideEffect;
    const DEP_KIND_ANON_ZERO_DEPS: DepKind = dep_kinds::AnonZeroDeps;
    const DEP_KIND_MAX: u16 = dep_node::DEP_KIND_VARIANTS - 1;
}

impl<'tcx> DepContext for TyCtxt<'tcx> {
    type Deps = DepsType;

    #[inline]
    fn with_stable_hashing_context<R>(self, f: impl FnOnce(StableHashingContext<'_>) -> R) -> R {
        TyCtxt::with_stable_hashing_context(self, f)
    }

    #[inline]
    fn dep_graph(&self) -> &DepGraph {
        &self.dep_graph
    }

    #[inline(always)]
    fn profiler(&self) -> &SelfProfilerRef {
        &self.prof
    }

    #[inline(always)]
    fn sess(&self) -> &Session {
        self.sess
    }

    #[inline]
    fn dep_kind_vtable(&self, dk: DepKind) -> &DepKindVTable<'tcx> {
        &self.dep_kind_vtables[dk.as_usize()]
    }

    fn with_reduced_queries<T>(self, f: impl FnOnce() -> T) -> T {
        with_reduced_queries!(f())
    }
}