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 use rustc_span::def_id::DefId;
  10
  11 use rustc_data_structures::fingerprint::Fingerprint;
  12 use std::borrow::Cow;
  13 use std::fmt::Debug;
  14 use std::hash::Hash;
  15
  16 // The parameter `CTX` is required in librustc_middle:
  17 // implementations may need to access the `'tcx` lifetime in `CTX = TyCtxt<'tcx>`.
  18 pub trait QueryConfig<CTX> {
  19     const NAME: &'static str;
  20     const CATEGORY: ProfileCategory;
  21
  22     type Key: Eq + Hash + Clone + Debug;
  23     type Value: Clone;
  24 }
  25
  26 pub trait QueryAccessors<CTX: QueryContext>: QueryConfig<CTX> {
  27     const ANON: bool;
  28     const EVAL_ALWAYS: bool;
  29     const DEP_KIND: CTX::DepKind;
  30
  31     type Cache: QueryCache<Key = Self::Key, Value = Self::Value>;
  32
  33     // Don't use this method to access query results, instead use the methods on TyCtxt
  34     fn query_state<'a>(tcx: CTX) -> &'a QueryState<CTX, Self::Cache>;
  35
  36     fn to_dep_node(tcx: CTX, key: &Self::Key) -> DepNode<CTX::DepKind>;
  37
  38     // Don't use this method to compute query results, instead use the methods on TyCtxt
  39     fn compute(tcx: CTX, key: Self::Key) -> Self::Value;
  40
  41     fn hash_result(
  42         hcx: &mut CTX::StableHashingContext,
  43         result: &Self::Value,
  44     ) -> Option<Fingerprint>;
  45
  46     fn handle_cycle_error(tcx: CTX, error: CycleError<CTX::Query>) -> Self::Value;
  47 }
  48
  49 pub trait QueryDescription<CTX: QueryContext>: QueryAccessors<CTX> {
  50     fn describe(tcx: CTX, key: Self::Key) -> Cow<'static, str>;
  51
  52     #[inline]
  53     fn cache_on_disk(_: CTX, _: Self::Key, _: Option<&Self::Value>) -> bool {
  54         false
  55     }
  56
  57     fn try_load_from_disk(_: CTX, _: SerializedDepNodeIndex) -> Option<Self::Value> {
  58         panic!("QueryDescription::load_from_disk() called for an unsupported query.")
  59     }
  60 }
  61
  62 impl<CTX: QueryContext, M> QueryDescription<CTX> for M
  63 where
  64     M: QueryAccessors<CTX, Key = DefId>,
  65 {
  66     default fn describe(tcx: CTX, def_id: DefId) -> Cow<'static, str> {
  67         if !tcx.verbose() {
  68             format!("processing `{}`", tcx.def_path_str(def_id)).into()
  69         } else {
  70             let name = ::std::any::type_name::<M>();
  71             format!("processing {:?} with query `{}`", def_id, name).into()
  72         }
  73     }
  74
  75     default fn cache_on_disk(_: CTX, _: Self::Key, _: Option<&Self::Value>) -> bool {
  76         false
  77     }
  78
  79     default fn try_load_from_disk(_: CTX, _: SerializedDepNodeIndex) -> Option<Self::Value> {
  80         panic!("QueryDescription::load_from_disk() called for an unsupported query.")
  81     }
  82 }