bjoernager/rust
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Auto merge of #119192 - michaelwoerister:mcp533-push, r=cjgillot

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Replace a number of FxHashMaps/Sets with stable-iteration-order alternatives

This PR replaces almost all of the remaining `FxHashMap`s in query results with either `FxIndexMap` or `UnordMap`. The only case that is missing is the `EffectiveVisibilities` struct which turned out to not be straightforward to transform. Once that is done too, we can remove the `HashStable` implementation from `HashMap`.

The first commit adds the `StableCompare` trait which is a companion trait to `StableOrd`. Some types like `Symbol` can be compared in a cross-session stable way, but their `Ord` implementation is not stable. In such cases, a `StableCompare` implementation can be provided to offer a lightweight way for stable sorting. The more heavyweight option is to sort via `ToStableHashKey`, but then sorting needs to have access to a stable hashing context and `ToStableHashKey` can also be expensive as in the case of `Symbol` where it has to allocate a `String`.

The rest of the commits are rather mechanical and don't overlap, so they are best reviewed individually.

Part of [MCP 533](https://github.com/rust-lang/compiler-team/issues/533).
This commit is contained in:
bors 2024-01-05 19:38:27 +00:00
commit b8c207435c
30 changed files with 256 additions and 147 deletions
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10
compiler/rustc_lint/src/foreign_modules.rs
View file

@ -1,5 +1,5 @@
use rustc_data_structures::fx::{FxHashMap, FxHashSet};
use rustc_data_structures::stack::ensure_sufficient_stack;
use rustc_data_structures::unord::{UnordMap, UnordSet};
use rustc_hir as hir;
use rustc_hir::def::DefKind;
use rustc_middle::query::Providers;
@ -72,7 +72,7 @@ struct ClashingExternDeclarations {
/// the symbol should be reported as a clashing declaration.
// FIXME: Technically, we could just store a &'tcx str here without issue; however, the
// `impl_lint_pass` macro doesn't currently support lints parametric over a lifetime.
seen_decls: FxHashMap<Symbol, hir::OwnerId>,
seen_decls: UnordMap<Symbol, hir::OwnerId>,
}
/// Differentiate between whether the name for an extern decl came from the link_name attribute or
@ -96,7 +96,7 @@ impl SymbolName {
impl ClashingExternDeclarations {
pub(crate) fn new() -> Self {
ClashingExternDeclarations { seen_decls: FxHashMap::default() }
ClashingExternDeclarations { seen_decls: Default::default() }
}
/// Insert a new foreign item into the seen set. If a symbol with the same name already exists
@ -209,12 +209,12 @@ fn structurally_same_type<'tcx>(
b: Ty<'tcx>,
ckind: types::CItemKind,
) -> bool {
let mut seen_types = FxHashSet::default();
let mut seen_types = UnordSet::default();
structurally_same_type_impl(&mut seen_types, tcx, param_env, a, b, ckind)
}
fn structurally_same_type_impl<'tcx>(
seen_types: &mut FxHashSet<(Ty<'tcx>, Ty<'tcx>)>,
seen_types: &mut UnordSet<(Ty<'tcx>, Ty<'tcx>)>,
tcx: TyCtxt<'tcx>,
param_env: ty::ParamEnv<'tcx>,
a: Ty<'tcx>,

11
compiler/rustc_lint/src/non_ascii_idents.rs
View file

@ -4,7 +4,8 @@ use crate::lints::{
};
use crate::{EarlyContext, EarlyLintPass, LintContext};
use rustc_ast as ast;
use rustc_data_structures::fx::FxHashMap;
use rustc_data_structures::fx::FxIndexMap;
use rustc_data_structures::unord::UnordMap;
use rustc_span::symbol::Symbol;
declare_lint! {
@ -194,8 +195,8 @@ impl EarlyLintPass for NonAsciiIdents {
}
if has_non_ascii_idents && check_confusable_idents {
let mut skeleton_map: FxHashMap<Symbol, (Symbol, Span, bool)> =
FxHashMap::with_capacity_and_hasher(symbols.len(), Default::default());
let mut skeleton_map: UnordMap<Symbol, (Symbol, Span, bool)> =
UnordMap::with_capacity(symbols.len());
let mut skeleton_buf = String::new();
for (&symbol, &sp) in symbols.iter() {
@ -248,8 +249,8 @@ impl EarlyLintPass for NonAsciiIdents {
Verified,
}
let mut script_states: FxHashMap<AugmentedScriptSet, ScriptSetUsage> =
FxHashMap::default();
let mut script_states: FxIndexMap<AugmentedScriptSet, ScriptSetUsage> =
Default::default();
let latin_augmented_script_set = AugmentedScriptSet::for_char('A');
script_states.insert(latin_augmented_script_set, ScriptSetUsage::Verified);