src/librustc_query_system/query/config.rs

   1 //! Query configuration and description traits.
   2
   3 use crate::dep_graph::DepNode;
   4 use crate::dep_graph::SerializedDepNodeIndex;
   5 use crate::query::caches::QueryCache;
   6 use crate::query::plumbing::CycleError;
   7 use crate::query::{QueryContext, QueryState};
   8 use rustc_data_structures::profiling::ProfileCategory;
   9
  10 use rustc_data_structures::fingerprint::Fingerprint;
  11 use std::borrow::Cow;
  12 use std::fmt::Debug;
  13 use std::hash::Hash;
  14
  15 // The parameter `CTX` is required in librustc_middle:
  16 // implementations may need to access the `'tcx` lifetime in `CTX = TyCtxt<'tcx>`.
  17 pub trait QueryConfig<CTX> {
  18     const NAME: &'static str;
  19     const CATEGORY: ProfileCategory;
  20
  21     type Key: Eq + Hash + Clone + Debug;
  22     type Value;
  23     type Stored: Clone;
  24 }
  25
  26 pub(crate) struct QueryVtable<CTX: QueryContext, K, V> {
  27     pub anon: bool,
  28     pub dep_kind: CTX::DepKind,
  29     pub eval_always: bool,
  30
  31     // Don't use this method to compute query results, instead use the methods on TyCtxt
  32     pub compute: fn(CTX, K) -> V,
  33
  34     pub hash_result: fn(&mut CTX::StableHashingContext, &V) -> Option<Fingerprint>,
  35     pub handle_cycle_error: fn(CTX, CycleError<CTX::Query>) -> V,
  36     pub cache_on_disk: fn(CTX, &K, Option<&V>) -> bool,
  37     pub try_load_from_disk: fn(CTX, SerializedDepNodeIndex) -> Option<V>,
  38 }
  39
  40 impl<CTX: QueryContext, K, V> QueryVtable<CTX, K, V> {
  41     pub(crate) fn to_dep_node(&self, tcx: CTX, key: &K) -> DepNode<CTX::DepKind>
  42     where
  43         K: crate::dep_graph::DepNodeParams<CTX>,
  44     {
  45         DepNode::construct(tcx, self.dep_kind, key)
  46     }
  47
  48     pub(crate) fn compute(&self, tcx: CTX, key: K) -> V {
  49         (self.compute)(tcx, key)
  50     }
  51
  52     pub(crate) fn hash_result(
  53         &self,
  54         hcx: &mut CTX::StableHashingContext,
  55         value: &V,
  56     ) -> Option<Fingerprint> {
  57         (self.hash_result)(hcx, value)
  58     }
  59
  60     pub(crate) fn handle_cycle_error(&self, tcx: CTX, error: CycleError<CTX::Query>) -> V {
  61         (self.handle_cycle_error)(tcx, error)
  62     }
  63
  64     pub(crate) fn cache_on_disk(&self, tcx: CTX, key: &K, value: Option<&V>) -> bool {
  65         (self.cache_on_disk)(tcx, key, value)
  66     }
  67
  68     pub(crate) fn try_load_from_disk(&self, tcx: CTX, index: SerializedDepNodeIndex) -> Option<V> {
  69         (self.try_load_from_disk)(tcx, index)
  70     }
  71 }
  72
  73 pub trait QueryAccessors<CTX: QueryContext>: QueryConfig<CTX> {
  74     const ANON: bool;
  75     const EVAL_ALWAYS: bool;
  76     const DEP_KIND: CTX::DepKind;
  77
  78     type Cache: QueryCache<Key = Self::Key, Stored = Self::Stored, Value = Self::Value>;
  79
  80     // Don't use this method to access query results, instead use the methods on TyCtxt
  81     fn query_state<'a>(tcx: CTX) -> &'a QueryState<CTX, Self::Cache>;
  82
  83     fn to_dep_node(tcx: CTX, key: &Self::Key) -> DepNode<CTX::DepKind>
  84     where
  85         Self::Key: crate::dep_graph::DepNodeParams<CTX>,
  86     {
  87         DepNode::construct(tcx, Self::DEP_KIND, key)
  88     }
  89
  90     // Don't use this method to compute query results, instead use the methods on TyCtxt
  91     fn compute(tcx: CTX, key: Self::Key) -> Self::Value;
  92
  93     fn hash_result(
  94         hcx: &mut CTX::StableHashingContext,
  95         result: &Self::Value,
  96     ) -> Option<Fingerprint>;
  97
  98     fn handle_cycle_error(tcx: CTX, error: CycleError<CTX::Query>) -> Self::Value;
  99 }
 100
 101 pub trait QueryDescription<CTX: QueryContext>: QueryAccessors<CTX> {
 102     fn describe(tcx: CTX, key: Self::Key) -> Cow<'static, str>;
 103
 104     #[inline]
 105     fn cache_on_disk(_: CTX, _: &Self::Key, _: Option<&Self::Value>) -> bool {
 106         false
 107     }
 108
 109     fn try_load_from_disk(_: CTX, _: SerializedDepNodeIndex) -> Option<Self::Value> {
 110         panic!("QueryDescription::load_from_disk() called for an unsupported query.")
 111     }
 112 }
 113
 114 pub(crate) trait QueryVtableExt<CTX: QueryContext, K, V> {
 115     const VTABLE: QueryVtable<CTX, K, V>;
 116 }
 117
 118 impl<CTX, Q> QueryVtableExt<CTX, Q::Key, Q::Value> for Q
 119 where
 120     CTX: QueryContext,
 121     Q: QueryDescription<CTX>,
 122 {
 123     const VTABLE: QueryVtable<CTX, Q::Key, Q::Value> = QueryVtable {
 124         anon: Q::ANON,
 125         dep_kind: Q::DEP_KIND,
 126         eval_always: Q::EVAL_ALWAYS,
 127         compute: Q::compute,
 128         hash_result: Q::hash_result,
 129         handle_cycle_error: Q::handle_cycle_error,
 130         cache_on_disk: Q::cache_on_disk,
 131         try_load_from_disk: Q::try_load_from_disk,
 132     };
 133 }