| //! This module defines the `DepNode` type which the compiler uses to represent |
| //! nodes in the dependency graph. A `DepNode` consists of a `DepKind` (which |
| //! specifies the kind of thing it represents, like a piece of HIR, MIR, etc) |
| //! and a `Fingerprint`, a 128 bit hash value the exact meaning of which |
| //! depends on the node's `DepKind`. Together, the kind and the fingerprint |
| //! fully identify a dependency node, even across multiple compilation sessions. |
| //! In other words, the value of the fingerprint does not depend on anything |
| //! that is specific to a given compilation session, like an unpredictable |
| //! interning key (e.g., NodeId, DefId, Symbol) or the numeric value of a |
| //! pointer. The concept behind this could be compared to how git commit hashes |
| //! uniquely identify a given commit and has a few advantages: |
| //! |
| //! * A `DepNode` can simply be serialized to disk and loaded in another session |
| //! without the need to do any "rebasing (like we have to do for Spans and |
| //! NodeIds) or "retracing" like we had to do for `DefId` in earlier |
| //! implementations of the dependency graph. |
| //! * A `Fingerprint` is just a bunch of bits, which allows `DepNode` to |
| //! implement `Copy`, `Sync`, `Send`, `Freeze`, etc. |
| //! * Since we just have a bit pattern, `DepNode` can be mapped from disk into |
| //! memory without any post-processing (e.g., "abomination-style" pointer |
| //! reconstruction). |
| //! * Because a `DepNode` is self-contained, we can instantiate `DepNodes` that |
| //! refer to things that do not exist anymore. In previous implementations |
| //! `DepNode` contained a `DefId`. A `DepNode` referring to something that |
| //! had been removed between the previous and the current compilation session |
| //! could not be instantiated because the current compilation session |
| //! contained no `DefId` for thing that had been removed. |
| //! |
| //! `DepNode` definition happens in the `define_dep_nodes!()` macro. This macro |
| //! defines the `DepKind` enum and a corresponding `DepConstructor` enum. The |
| //! `DepConstructor` enum links a `DepKind` to the parameters that are needed at |
| //! runtime in order to construct a valid `DepNode` fingerprint. |
| //! |
| //! Because the macro sees what parameters a given `DepKind` requires, it can |
| //! "infer" some properties for each kind of `DepNode`: |
| //! |
| //! * Whether a `DepNode` of a given kind has any parameters at all. Some |
| //! `DepNode`s, like `Krate`, represent global concepts with only one value. |
| //! * Whether it is possible, in principle, to reconstruct a query key from a |
| //! given `DepNode`. Many `DepKind`s only require a single `DefId` parameter, |
| //! in which case it is possible to map the node's fingerprint back to the |
| //! `DefId` it was computed from. In other cases, too much information gets |
| //! lost during fingerprint computation. |
| //! |
| //! The `DepConstructor` enum, together with `DepNode::new()` ensures that only |
| //! valid `DepNode` instances can be constructed. For example, the API does not |
| //! allow for constructing parameterless `DepNode`s with anything other |
| //! than a zeroed out fingerprint. More generally speaking, it relieves the |
| //! user of the `DepNode` API of having to know how to compute the expected |
| //! fingerprint for a given set of node parameters. |
| |
| use crate::hir::def_id::{CrateNum, DefId, DefIndex, CRATE_DEF_INDEX}; |
| use crate::hir::map::DefPathHash; |
| use crate::hir::HirId; |
| use crate::mir; |
| use crate::mir::interpret::GlobalId; |
| |
| use crate::ich::{Fingerprint, StableHashingContext}; |
| use crate::traits; |
| use crate::traits::query::{ |
| CanonicalPredicateGoal, CanonicalProjectionGoal, CanonicalTyGoal, |
| CanonicalTypeOpAscribeUserTypeGoal, CanonicalTypeOpEqGoal, CanonicalTypeOpNormalizeGoal, |
| CanonicalTypeOpProvePredicateGoal, CanonicalTypeOpSubtypeGoal, |
| }; |
| use crate::ty::subst::SubstsRef; |
| use crate::ty::{self, ParamEnvAnd, Ty, TyCtxt}; |
| use rustc_data_structures::stable_hasher::{HashStable, StableHasher}; |
| use rustc_span::symbol::Symbol; |
| use std::fmt; |
| use std::hash::Hash; |
| |
| // erase!() just makes tokens go away. It's used to specify which macro argument |
| // is repeated (i.e., which sub-expression of the macro we are in) but don't need |
| // to actually use any of the arguments. |
| macro_rules! erase { |
| ($x:tt) => {{}}; |
| } |
| |
| macro_rules! replace { |
| ($x:tt with $($y:tt)*) => ($($y)*) |
| } |
| |
| macro_rules! is_anon_attr { |
| (anon) => { |
| true |
| }; |
| ($attr:ident) => { |
| false |
| }; |
| } |
| |
| macro_rules! is_eval_always_attr { |
| (eval_always) => { |
| true |
| }; |
| ($attr:ident) => { |
| false |
| }; |
| } |
| |
| macro_rules! contains_anon_attr { |
| ($($attr:ident),*) => ({$(is_anon_attr!($attr) | )* false}); |
| } |
| |
| macro_rules! contains_eval_always_attr { |
| ($($attr:ident),*) => ({$(is_eval_always_attr!($attr) | )* false}); |
| } |
| |
| macro_rules! define_dep_nodes { |
| (<$tcx:tt> |
| $( |
| [$($attr:ident),* ] |
| $variant:ident $(( $tuple_arg_ty:ty $(,)? ))* |
| $({ $($struct_arg_name:ident : $struct_arg_ty:ty),* })* |
| ,)* |
| ) => ( |
| #[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, |
| RustcEncodable, RustcDecodable)] |
| pub enum DepKind { |
| $($variant),* |
| } |
| |
| impl DepKind { |
| #[allow(unreachable_code)] |
| pub fn can_reconstruct_query_key<$tcx>(&self) -> bool { |
| match *self { |
| $( |
| DepKind :: $variant => { |
| if contains_anon_attr!($($attr),*) { |
| return false; |
| } |
| |
| // tuple args |
| $({ |
| return <$tuple_arg_ty as DepNodeParams> |
| ::CAN_RECONSTRUCT_QUERY_KEY; |
| })* |
| |
| // struct args |
| $({ |
| |
| return <( $($struct_arg_ty,)* ) as DepNodeParams> |
| ::CAN_RECONSTRUCT_QUERY_KEY; |
| })* |
| |
| true |
| } |
| )* |
| } |
| } |
| |
| pub fn is_anon(&self) -> bool { |
| match *self { |
| $( |
| DepKind :: $variant => { contains_anon_attr!($($attr),*) } |
| )* |
| } |
| } |
| |
| pub fn is_eval_always(&self) -> bool { |
| match *self { |
| $( |
| DepKind :: $variant => { contains_eval_always_attr!($($attr), *) } |
| )* |
| } |
| } |
| |
| #[allow(unreachable_code)] |
| pub fn has_params(&self) -> bool { |
| match *self { |
| $( |
| DepKind :: $variant => { |
| // tuple args |
| $({ |
| erase!($tuple_arg_ty); |
| return true; |
| })* |
| |
| // struct args |
| $({ |
| $(erase!($struct_arg_name);)* |
| return true; |
| })* |
| |
| false |
| } |
| )* |
| } |
| } |
| } |
| |
| pub enum DepConstructor<$tcx> { |
| $( |
| $variant $(( $tuple_arg_ty ))* |
| $({ $($struct_arg_name : $struct_arg_ty),* })* |
| ),* |
| } |
| |
| #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, |
| RustcEncodable, RustcDecodable)] |
| pub struct DepNode { |
| pub kind: DepKind, |
| pub hash: Fingerprint, |
| } |
| |
| impl DepNode { |
| #[allow(unreachable_code, non_snake_case)] |
| pub fn new<'tcx>(tcx: TyCtxt<'tcx>, |
| dep: DepConstructor<'tcx>) |
| -> DepNode |
| { |
| match dep { |
| $( |
| DepConstructor :: $variant $(( replace!(($tuple_arg_ty) with arg) ))* |
| $({ $($struct_arg_name),* })* |
| => |
| { |
| // tuple args |
| $({ |
| erase!($tuple_arg_ty); |
| let hash = DepNodeParams::to_fingerprint(&arg, tcx); |
| let dep_node = DepNode { |
| kind: DepKind::$variant, |
| hash |
| }; |
| |
| #[cfg(debug_assertions)] |
| { |
| if !dep_node.kind.can_reconstruct_query_key() && |
| (tcx.sess.opts.debugging_opts.incremental_info || |
| tcx.sess.opts.debugging_opts.query_dep_graph) |
| { |
| tcx.dep_graph.register_dep_node_debug_str(dep_node, || { |
| arg.to_debug_str(tcx) |
| }); |
| } |
| } |
| |
| return dep_node; |
| })* |
| |
| // struct args |
| $({ |
| let tupled_args = ( $($struct_arg_name,)* ); |
| let hash = DepNodeParams::to_fingerprint(&tupled_args, |
| tcx); |
| let dep_node = DepNode { |
| kind: DepKind::$variant, |
| hash |
| }; |
| |
| #[cfg(debug_assertions)] |
| { |
| if !dep_node.kind.can_reconstruct_query_key() && |
| (tcx.sess.opts.debugging_opts.incremental_info || |
| tcx.sess.opts.debugging_opts.query_dep_graph) |
| { |
| tcx.dep_graph.register_dep_node_debug_str(dep_node, || { |
| tupled_args.to_debug_str(tcx) |
| }); |
| } |
| } |
| |
| return dep_node; |
| })* |
| |
| DepNode { |
| kind: DepKind::$variant, |
| hash: Fingerprint::ZERO, |
| } |
| } |
| )* |
| } |
| } |
| |
| /// Construct a DepNode from the given DepKind and DefPathHash. This |
| /// method will assert that the given DepKind actually requires a |
| /// single DefId/DefPathHash parameter. |
| pub fn from_def_path_hash(kind: DepKind, |
| def_path_hash: DefPathHash) |
| -> DepNode { |
| debug_assert!(kind.can_reconstruct_query_key() && kind.has_params()); |
| DepNode { |
| kind, |
| hash: def_path_hash.0, |
| } |
| } |
| |
| /// Creates a new, parameterless DepNode. This method will assert |
| /// that the DepNode corresponding to the given DepKind actually |
| /// does not require any parameters. |
| pub fn new_no_params(kind: DepKind) -> DepNode { |
| debug_assert!(!kind.has_params()); |
| DepNode { |
| kind, |
| hash: Fingerprint::ZERO, |
| } |
| } |
| |
| /// Extracts the DefId corresponding to this DepNode. This will work |
| /// if two conditions are met: |
| /// |
| /// 1. The Fingerprint of the DepNode actually is a DefPathHash, and |
| /// 2. the item that the DefPath refers to exists in the current tcx. |
| /// |
| /// Condition (1) is determined by the DepKind variant of the |
| /// DepNode. Condition (2) might not be fulfilled if a DepNode |
| /// refers to something from the previous compilation session that |
| /// has been removed. |
| pub fn extract_def_id(&self, tcx: TyCtxt<'_>) -> Option<DefId> { |
| if self.kind.can_reconstruct_query_key() { |
| let def_path_hash = DefPathHash(self.hash); |
| tcx.def_path_hash_to_def_id.as_ref()? |
| .get(&def_path_hash).cloned() |
| } else { |
| None |
| } |
| } |
| |
| /// Used in testing |
| pub fn from_label_string(label: &str, |
| def_path_hash: DefPathHash) |
| -> Result<DepNode, ()> { |
| let kind = match label { |
| $( |
| stringify!($variant) => DepKind::$variant, |
| )* |
| _ => return Err(()), |
| }; |
| |
| if !kind.can_reconstruct_query_key() { |
| return Err(()); |
| } |
| |
| if kind.has_params() { |
| Ok(def_path_hash.to_dep_node(kind)) |
| } else { |
| Ok(DepNode::new_no_params(kind)) |
| } |
| } |
| |
| /// Used in testing |
| pub fn has_label_string(label: &str) -> bool { |
| match label { |
| $( |
| stringify!($variant) => true, |
| )* |
| _ => false, |
| } |
| } |
| } |
| |
| /// Contains variant => str representations for constructing |
| /// DepNode groups for tests. |
| #[allow(dead_code, non_upper_case_globals)] |
| pub mod label_strs { |
| $( |
| pub const $variant: &str = stringify!($variant); |
| )* |
| } |
| ); |
| } |
| |
| impl fmt::Debug for DepNode { |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| write!(f, "{:?}", self.kind)?; |
| |
| if !self.kind.has_params() && !self.kind.is_anon() { |
| return Ok(()); |
| } |
| |
| write!(f, "(")?; |
| |
| crate::ty::tls::with_opt(|opt_tcx| { |
| if let Some(tcx) = opt_tcx { |
| if let Some(def_id) = self.extract_def_id(tcx) { |
| write!(f, "{}", tcx.def_path_debug_str(def_id))?; |
| } else if let Some(ref s) = tcx.dep_graph.dep_node_debug_str(*self) { |
| write!(f, "{}", s)?; |
| } else { |
| write!(f, "{}", self.hash)?; |
| } |
| } else { |
| write!(f, "{}", self.hash)?; |
| } |
| Ok(()) |
| })?; |
| |
| write!(f, ")") |
| } |
| } |
| |
| impl DefPathHash { |
| pub fn to_dep_node(self, kind: DepKind) -> DepNode { |
| DepNode::from_def_path_hash(kind, self) |
| } |
| } |
| |
| rustc_dep_node_append!([define_dep_nodes!][ <'tcx> |
| // We use this for most things when incr. comp. is turned off. |
| [] Null, |
| |
| // Represents the `Krate` as a whole (the `hir::Krate` value) (as |
| // distinct from the krate module). This is basically a hash of |
| // the entire krate, so if you read from `Krate` (e.g., by calling |
| // `tcx.hir().krate()`), we will have to assume that any change |
| // means that you need to be recompiled. This is because the |
| // `Krate` value gives you access to all other items. To avoid |
| // this fate, do not call `tcx.hir().krate()`; instead, prefer |
| // wrappers like `tcx.visit_all_items_in_krate()`. If there is no |
| // suitable wrapper, you can use `tcx.dep_graph.ignore()` to gain |
| // access to the krate, but you must remember to add suitable |
| // edges yourself for the individual items that you read. |
| [eval_always] Krate, |
| |
| // Represents the body of a function or method. The def-id is that of the |
| // function/method. |
| [eval_always] HirBody(DefId), |
| |
| // Represents the HIR node with the given node-id |
| [eval_always] Hir(DefId), |
| |
| // Represents metadata from an extern crate. |
| [eval_always] CrateMetadata(CrateNum), |
| |
| [eval_always] AllLocalTraitImpls, |
| |
| [anon] TraitSelect, |
| |
| [] CompileCodegenUnit(Symbol), |
| |
| [eval_always] Analysis(CrateNum), |
| ]); |
| |
| pub trait RecoverKey<'tcx>: Sized { |
| fn recover(tcx: TyCtxt<'tcx>, dep_node: &DepNode) -> Option<Self>; |
| } |
| |
| impl RecoverKey<'tcx> for CrateNum { |
| fn recover(tcx: TyCtxt<'tcx>, dep_node: &DepNode) -> Option<Self> { |
| dep_node.extract_def_id(tcx).map(|id| id.krate) |
| } |
| } |
| |
| impl RecoverKey<'tcx> for DefId { |
| fn recover(tcx: TyCtxt<'tcx>, dep_node: &DepNode) -> Option<Self> { |
| dep_node.extract_def_id(tcx) |
| } |
| } |
| |
| impl RecoverKey<'tcx> for DefIndex { |
| fn recover(tcx: TyCtxt<'tcx>, dep_node: &DepNode) -> Option<Self> { |
| dep_node.extract_def_id(tcx).map(|id| id.index) |
| } |
| } |
| |
| trait DepNodeParams<'tcx>: fmt::Debug { |
| const CAN_RECONSTRUCT_QUERY_KEY: bool; |
| |
| /// This method turns the parameters of a DepNodeConstructor into an opaque |
| /// Fingerprint to be used in DepNode. |
| /// Not all DepNodeParams support being turned into a Fingerprint (they |
| /// don't need to if the corresponding DepNode is anonymous). |
| fn to_fingerprint(&self, _: TyCtxt<'tcx>) -> Fingerprint { |
| panic!("Not implemented. Accidentally called on anonymous node?") |
| } |
| |
| fn to_debug_str(&self, _: TyCtxt<'tcx>) -> String { |
| format!("{:?}", self) |
| } |
| } |
| |
| impl<'tcx, T> DepNodeParams<'tcx> for T |
| where |
| T: HashStable<StableHashingContext<'tcx>> + fmt::Debug, |
| { |
| default const CAN_RECONSTRUCT_QUERY_KEY: bool = false; |
| |
| default fn to_fingerprint(&self, tcx: TyCtxt<'tcx>) -> Fingerprint { |
| let mut hcx = tcx.create_stable_hashing_context(); |
| let mut hasher = StableHasher::new(); |
| |
| self.hash_stable(&mut hcx, &mut hasher); |
| |
| hasher.finish() |
| } |
| |
| default fn to_debug_str(&self, _: TyCtxt<'tcx>) -> String { |
| format!("{:?}", *self) |
| } |
| } |
| |
| impl<'tcx> DepNodeParams<'tcx> for DefId { |
| const CAN_RECONSTRUCT_QUERY_KEY: bool = true; |
| |
| fn to_fingerprint(&self, tcx: TyCtxt<'_>) -> Fingerprint { |
| tcx.def_path_hash(*self).0 |
| } |
| |
| fn to_debug_str(&self, tcx: TyCtxt<'tcx>) -> String { |
| tcx.def_path_str(*self) |
| } |
| } |
| |
| impl<'tcx> DepNodeParams<'tcx> for DefIndex { |
| const CAN_RECONSTRUCT_QUERY_KEY: bool = true; |
| |
| fn to_fingerprint(&self, tcx: TyCtxt<'_>) -> Fingerprint { |
| tcx.hir().definitions().def_path_hash(*self).0 |
| } |
| |
| fn to_debug_str(&self, tcx: TyCtxt<'tcx>) -> String { |
| tcx.def_path_str(DefId::local(*self)) |
| } |
| } |
| |
| impl<'tcx> DepNodeParams<'tcx> for CrateNum { |
| const CAN_RECONSTRUCT_QUERY_KEY: bool = true; |
| |
| fn to_fingerprint(&self, tcx: TyCtxt<'_>) -> Fingerprint { |
| let def_id = DefId { krate: *self, index: CRATE_DEF_INDEX }; |
| tcx.def_path_hash(def_id).0 |
| } |
| |
| fn to_debug_str(&self, tcx: TyCtxt<'tcx>) -> String { |
| tcx.crate_name(*self).to_string() |
| } |
| } |
| |
| impl<'tcx> DepNodeParams<'tcx> for (DefId, DefId) { |
| const CAN_RECONSTRUCT_QUERY_KEY: bool = false; |
| |
| // We actually would not need to specialize the implementation of this |
| // method but it's faster to combine the hashes than to instantiate a full |
| // hashing context and stable-hashing state. |
| fn to_fingerprint(&self, tcx: TyCtxt<'_>) -> Fingerprint { |
| let (def_id_0, def_id_1) = *self; |
| |
| let def_path_hash_0 = tcx.def_path_hash(def_id_0); |
| let def_path_hash_1 = tcx.def_path_hash(def_id_1); |
| |
| def_path_hash_0.0.combine(def_path_hash_1.0) |
| } |
| |
| fn to_debug_str(&self, tcx: TyCtxt<'tcx>) -> String { |
| let (def_id_0, def_id_1) = *self; |
| |
| format!("({}, {})", tcx.def_path_debug_str(def_id_0), tcx.def_path_debug_str(def_id_1)) |
| } |
| } |
| |
| impl<'tcx> DepNodeParams<'tcx> for HirId { |
| const CAN_RECONSTRUCT_QUERY_KEY: bool = false; |
| |
| // We actually would not need to specialize the implementation of this |
| // method but it's faster to combine the hashes than to instantiate a full |
| // hashing context and stable-hashing state. |
| fn to_fingerprint(&self, tcx: TyCtxt<'_>) -> Fingerprint { |
| let HirId { owner, local_id } = *self; |
| |
| let def_path_hash = tcx.def_path_hash(DefId::local(owner)); |
| let local_id = Fingerprint::from_smaller_hash(local_id.as_u32().into()); |
| |
| def_path_hash.0.combine(local_id) |
| } |
| } |
| |
| /// A "work product" corresponds to a `.o` (or other) file that we |
| /// save in between runs. These IDs do not have a `DefId` but rather |
| /// some independent path or string that persists between runs without |
| /// the need to be mapped or unmapped. (This ensures we can serialize |
| /// them even in the absence of a tcx.) |
| #[derive( |
| Clone, |
| Copy, |
| Debug, |
| PartialEq, |
| Eq, |
| PartialOrd, |
| Ord, |
| Hash, |
| RustcEncodable, |
| RustcDecodable, |
| HashStable |
| )] |
| pub struct WorkProductId { |
| hash: Fingerprint, |
| } |
| |
| impl WorkProductId { |
| pub fn from_cgu_name(cgu_name: &str) -> WorkProductId { |
| let mut hasher = StableHasher::new(); |
| cgu_name.len().hash(&mut hasher); |
| cgu_name.hash(&mut hasher); |
| WorkProductId { hash: hasher.finish() } |
| } |
| |
| pub fn from_fingerprint(fingerprint: Fingerprint) -> WorkProductId { |
| WorkProductId { hash: fingerprint } |
| } |
| } |