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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14
compiler/rustc_codegen_ssa/src/back/symbol_export.rs
View file

@ -3,7 +3,7 @@ use crate::base::allocator_kind_for_codegen;
use std::collections::hash_map::Entry::*;
use rustc_ast::expand::allocator::{ALLOCATOR_METHODS, NO_ALLOC_SHIM_IS_UNSTABLE};
use rustc_data_structures::fx::FxHashMap;
use rustc_data_structures::unord::UnordMap;
use rustc_hir::def::DefKind;
use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, LocalDefId, LOCAL_CRATE};
use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
@ -393,10 +393,10 @@ fn exported_symbols_provider_local(
fn upstream_monomorphizations_provider(
tcx: TyCtxt<'_>,
(): (),
) -> DefIdMap<FxHashMap<GenericArgsRef<'_>, CrateNum>> {
) -> DefIdMap<UnordMap<GenericArgsRef<'_>, CrateNum>> {
let cnums = tcx.crates(());
let mut instances: DefIdMap<FxHashMap<_, _>> = Default::default();
let mut instances: DefIdMap<UnordMap<_, _>> = Default::default();
let drop_in_place_fn_def_id = tcx.lang_items().drop_in_place_fn();
@ -445,7 +445,7 @@ fn upstream_monomorphizations_provider(
fn upstream_monomorphizations_for_provider(
tcx: TyCtxt<'_>,
def_id: DefId,
) -> Option<&FxHashMap<GenericArgsRef<'_>, CrateNum>> {
) -> Option<&UnordMap<GenericArgsRef<'_>, CrateNum>> {
debug_assert!(!def_id.is_local());
tcx.upstream_monomorphizations(()).get(&def_id)
}
@ -656,7 +656,7 @@ fn maybe_emutls_symbol_name<'tcx>(
}
}
fn wasm_import_module_map(tcx: TyCtxt<'_>, cnum: CrateNum) -> FxHashMap<DefId, String> {
fn wasm_import_module_map(tcx: TyCtxt<'_>, cnum: CrateNum) -> DefIdMap<String> {
// Build up a map from DefId to a `NativeLib` structure, where
// `NativeLib` internally contains information about
// `#[link(wasm_import_module = "...")]` for example.
@ -665,9 +665,9 @@ fn wasm_import_module_map(tcx: TyCtxt<'_>, cnum: CrateNum) -> FxHashMap<DefId, S
let def_id_to_native_lib = native_libs
.iter()
.filter_map(|lib| lib.foreign_module.map(|id| (id, lib)))
.collect::<FxHashMap<_, _>>();
.collect::<DefIdMap<_>>();
let mut ret = FxHashMap::default();
let mut ret = DefIdMap::default();
for (def_id, lib) in tcx.foreign_modules(cnum).iter() {
let module = def_id_to_native_lib.get(def_id).and_then(|s| s.wasm_import_module());
let Some(module) = module else { continue };

4
compiler/rustc_codegen_ssa/src/target_features.rs
View file

@ -1,8 +1,8 @@
use crate::errors;
use rustc_ast::ast;
use rustc_attr::InstructionSetAttr;
use rustc_data_structures::fx::FxHashMap;
use rustc_data_structures::fx::FxIndexSet;
use rustc_data_structures::unord::UnordMap;
use rustc_errors::Applicability;
use rustc_hir::def::DefKind;
use rustc_hir::def_id::DefId;
@ -18,7 +18,7 @@ use rustc_span::Span;
pub fn from_target_feature(
tcx: TyCtxt<'_>,
attr: &ast::Attribute,
supported_target_features: &FxHashMap<String, Option<Symbol>>,
supported_target_features: &UnordMap<String, Option<Symbol>>,
target_features: &mut Vec<Symbol>,
) {
let Some(list) = attr.meta_item_list() else { return };