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[Experiment] Replace crate-hash with simple timestamp. #94852

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[Experiment] Replace crate-hash with simple timestamp. #94852

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25 changes: 1 addition & 24 deletions compiler/rustc_ast_lowering/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -461,33 +461,10 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
hir::OwnerNode::Crate(lctx.arena.alloc(module))
});

let hir_hash = self.compute_hir_hash();

let krate = hir::Crate { owners: self.owners, hir_hash };
let krate = hir::Crate { owners: self.owners };
self.arena.alloc(krate)
}

/// Compute the hash for the HIR of the full crate.
/// This hash will then be part of the crate_hash which is stored in the metadata.
fn compute_hir_hash(&mut self) -> Fingerprint {
let definitions = self.resolver.definitions();
let mut hir_body_nodes: Vec<_> = self
.owners
.iter_enumerated()
.filter_map(|(def_id, info)| {
let info = info.as_owner()?;
let def_path_hash = definitions.def_path_hash(def_id);
Some((def_path_hash, info))
})
.collect();
hir_body_nodes.sort_unstable_by_key(|bn| bn.0);

let mut stable_hasher = StableHasher::new();
let mut hcx = self.resolver.create_stable_hashing_context();
hir_body_nodes.hash_stable(&mut hcx, &mut stable_hasher);
stable_hasher.finish()
}

fn with_hir_id_owner(
&mut self,
owner: NodeId,
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1 change: 0 additions & 1 deletion compiler/rustc_hir/src/hir.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -776,7 +776,6 @@ impl<T> MaybeOwner<T> {
#[derive(Debug)]
pub struct Crate<'hir> {
pub owners: IndexVec<LocalDefId, MaybeOwner<&'hir OwnerInfo<'hir>>>,
pub hir_hash: Fingerprint,
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Why this change? This may force re-executions that are unrelated to crate_hash.

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Yes, that's true, making the hir_crate query no_hash is an unrelated change. Although from the performance results it looks like it does not make much of difference?

}

/// A block of statements `{ .. }`, which may have a label (in this case the
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11 changes: 2 additions & 9 deletions compiler/rustc_hir/src/stable_hash_impls.rs
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@@ -1,8 +1,8 @@
use rustc_data_structures::stable_hasher::{HashStable, StableHasher, ToStableHashKey};

use crate::hir::{
AttributeMap, BodyId, Crate, Expr, ForeignItem, ForeignItemId, ImplItem, ImplItemId, Item,
ItemId, OwnerNodes, TraitCandidate, TraitItem, TraitItemId, Ty, VisibilityKind,
AttributeMap, BodyId, Expr, ForeignItem, ForeignItemId, ImplItem, ImplItemId, Item, ItemId,
OwnerNodes, TraitCandidate, TraitItem, TraitItemId, Ty, VisibilityKind,
};
use crate::hir_id::{HirId, ItemLocalId};
use rustc_span::def_id::DefPathHash;
Expand Down Expand Up @@ -229,13 +229,6 @@ impl<'tcx, HirCtx: crate::HashStableContext> HashStable<HirCtx> for AttributeMap
}
}

impl<HirCtx: crate::HashStableContext> HashStable<HirCtx> for Crate<'_> {
fn hash_stable(&self, hcx: &mut HirCtx, hasher: &mut StableHasher) {
let Crate { owners: _, hir_hash } = self;
hir_hash.hash_stable(hcx, hasher)
}
}

impl<HirCtx: crate::HashStableContext> HashStable<HirCtx> for TraitCandidate {
fn hash_stable(&self, hcx: &mut HirCtx, hasher: &mut StableHasher) {
hcx.hash_hir_trait_candidate(self, hasher)
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69 changes: 5 additions & 64 deletions compiler/rustc_middle/src/hir/map/mod.rs
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Original file line number Diff line number Diff line change
@@ -1,8 +1,6 @@
use crate::hir::{ModuleItems, Owner};
use crate::ty::TyCtxt;
use rustc_ast as ast;
use rustc_data_structures::fingerprint::Fingerprint;
use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
use rustc_data_structures::svh::Svh;
use rustc_data_structures::sync::{par_for_each_in, Send, Sync};
use rustc_hir::def::{DefKind, Res};
Expand All @@ -13,12 +11,12 @@ use rustc_hir::itemlikevisit::ItemLikeVisitor;
use rustc_hir::*;
use rustc_index::vec::Idx;
use rustc_middle::hir::nested_filter;
use rustc_span::def_id::StableCrateId;
use rustc_span::source_map::Spanned;
use rustc_span::symbol::{kw, sym, Ident, Symbol};
use rustc_span::Span;
use rustc_target::spec::abi::Abi;
use std::collections::VecDeque;
use std::time::SystemTime;

fn fn_decl<'hir>(node: Node<'hir>) -> Option<&'hir FnDecl<'hir>> {
match node {
Expand Down Expand Up @@ -1088,69 +1086,12 @@ impl<'hir> intravisit::Map<'hir> for Map<'hir> {
}
}

pub(super) fn crate_hash(tcx: TyCtxt<'_>, crate_num: CrateNum) -> Svh {
pub(super) fn crate_hash(_: TyCtxt<'_>, crate_num: CrateNum) -> Svh {
debug_assert_eq!(crate_num, LOCAL_CRATE);
let krate = tcx.hir_crate(());
let hir_body_hash = krate.hir_hash;

let upstream_crates = upstream_crates(tcx);

// We hash the final, remapped names of all local source files so we
// don't have to include the path prefix remapping commandline args.
// If we included the full mapping in the SVH, we could only have
// reproducible builds by compiling from the same directory. So we just
// hash the result of the mapping instead of the mapping itself.
let mut source_file_names: Vec<_> = tcx
.sess
.source_map()
.files()
.iter()
.filter(|source_file| source_file.cnum == LOCAL_CRATE)
.map(|source_file| source_file.name_hash)
.collect();

source_file_names.sort_unstable();

let mut hcx = tcx.create_stable_hashing_context();
let mut stable_hasher = StableHasher::new();
hir_body_hash.hash_stable(&mut hcx, &mut stable_hasher);
upstream_crates.hash_stable(&mut hcx, &mut stable_hasher);
source_file_names.hash_stable(&mut hcx, &mut stable_hasher);
if tcx.sess.opts.debugging_opts.incremental_relative_spans {
let definitions = &tcx.untracked_resolutions.definitions;
let mut owner_spans: Vec<_> = krate
.owners
.iter_enumerated()
.filter_map(|(def_id, info)| {
let _ = info.as_owner()?;
let def_path_hash = definitions.def_path_hash(def_id);
let span = definitions.def_span(def_id);
debug_assert_eq!(span.parent(), None);
Some((def_path_hash, span))
})
.collect();
owner_spans.sort_unstable_by_key(|bn| bn.0);
owner_spans.hash_stable(&mut hcx, &mut stable_hasher);
}
tcx.sess.opts.dep_tracking_hash(true).hash_stable(&mut hcx, &mut stable_hasher);
tcx.sess.local_stable_crate_id().hash_stable(&mut hcx, &mut stable_hasher);

let crate_hash: Fingerprint = stable_hasher.finish();
Svh::new(crate_hash.to_smaller_hash())
}

fn upstream_crates(tcx: TyCtxt<'_>) -> Vec<(StableCrateId, Svh)> {
let mut upstream_crates: Vec<_> = tcx
.crates(())
.iter()
.map(|&cnum| {
let stable_crate_id = tcx.resolutions(()).cstore.stable_crate_id(cnum);
let hash = tcx.crate_hash(cnum);
(stable_crate_id, hash)
})
.collect();
upstream_crates.sort_unstable_by_key(|&(stable_crate_id, _)| stable_crate_id);
upstream_crates
// TEST: Turn crate hash into a time-stamp/build-id
let random = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_nanos();
Svh::new((random as u64).wrapping_add((random >> 64) as u64))
}

fn hir_id_to_string(map: Map<'_>, id: HirId) -> String {
Expand Down
1 change: 1 addition & 0 deletions compiler/rustc_middle/src/query/mod.rs
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Expand Up @@ -42,6 +42,7 @@ rustc_queries! {
/// prefer wrappers like `tcx.visit_all_items_in_krate()`.
query hir_crate(key: ()) -> &'tcx Crate<'tcx> {
eval_always
no_hash
desc { "get the crate HIR" }
}

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1 change: 1 addition & 0 deletions src/test/ui/svh-add-nothing.rs
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@@ -1,3 +1,4 @@
// ignore-test
// run-pass
// note that these aux-build directives must be in this order
// aux-build:svh-a-base.rs
Expand Down