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Auto merge of rust-lang#82985 - cjgillot:lint, r=jackh726
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Cleanup the computation of lint levels

This now uses an `IndexVec` and a special root `LintStackIndex = 0` to encode command-line levels.
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bors committed Jul 6, 2021
2 parents 72b0c7d + 5a731ff commit d5a406b
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Showing 2 changed files with 37 additions and 62 deletions.
16 changes: 8 additions & 8 deletions compiler/rustc_lint/src/levels.rs
Original file line number Diff line number Diff line change
Expand Up @@ -11,7 +11,8 @@ use rustc_middle::hir::map::Map;
use rustc_middle::lint::LevelAndSource;
use rustc_middle::lint::LintDiagnosticBuilder;
use rustc_middle::lint::{
struct_lint_level, LintLevelMap, LintLevelSets, LintLevelSource, LintSet,
struct_lint_level, LintLevelMap, LintLevelSets, LintLevelSource, LintSet, LintStackIndex,
COMMAND_LINE,
};
use rustc_middle::ty::query::Providers;
use rustc_middle::ty::TyCtxt;
Expand Down Expand Up @@ -50,15 +51,15 @@ fn lint_levels(tcx: TyCtxt<'_>, (): ()) -> LintLevelMap {
pub struct LintLevelsBuilder<'s> {
sess: &'s Session,
sets: LintLevelSets,
id_to_set: FxHashMap<HirId, u32>,
cur: u32,
id_to_set: FxHashMap<HirId, LintStackIndex>,
cur: LintStackIndex,
warn_about_weird_lints: bool,
store: &'s LintStore,
crate_attrs: &'s [ast::Attribute],
}

pub struct BuilderPush {
prev: u32,
prev: LintStackIndex,
pub changed: bool,
}

Expand All @@ -72,7 +73,7 @@ impl<'s> LintLevelsBuilder<'s> {
let mut builder = LintLevelsBuilder {
sess,
sets: LintLevelSets::new(),
cur: 0,
cur: COMMAND_LINE,
id_to_set: Default::default(),
warn_about_weird_lints,
store,
Expand Down Expand Up @@ -120,7 +121,7 @@ impl<'s> LintLevelsBuilder<'s> {
}
}

self.sets.list.push(LintSet::CommandLine { specs });
self.cur = self.sets.list.push(LintSet { specs, parent: COMMAND_LINE });
}

/// Attempts to insert the `id` to `level_src` map entry. If unsuccessful
Expand Down Expand Up @@ -523,8 +524,7 @@ impl<'s> LintLevelsBuilder<'s> {

let prev = self.cur;
if !specs.is_empty() {
self.cur = self.sets.list.len() as u32;
self.sets.list.push(LintSet::Node { specs, parent: prev });
self.cur = self.sets.list.push(LintSet { specs, parent: prev });
}

BuilderPush { prev, changed: prev != self.cur }
Expand Down
83 changes: 29 additions & 54 deletions compiler/rustc_middle/src/lint.rs
Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,7 @@ use rustc_data_structures::fx::FxHashMap;
use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
use rustc_errors::{DiagnosticBuilder, DiagnosticId};
use rustc_hir::HirId;
use rustc_index::vec::IndexVec;
use rustc_session::lint::{
builtin::{self, FORBIDDEN_LINT_GROUPS},
FutureIncompatibilityReason, Level, Lint, LintId,
Expand Down Expand Up @@ -51,35 +52,37 @@ impl LintLevelSource {
/// A tuple of a lint level and its source.
pub type LevelAndSource = (Level, LintLevelSource);

#[derive(Debug)]
#[derive(Debug, HashStable)]
pub struct LintLevelSets {
pub list: Vec<LintSet>,
pub list: IndexVec<LintStackIndex, LintSet>,
pub lint_cap: Level,
}

#[derive(Debug)]
pub enum LintSet {
CommandLine {
// -A,-W,-D flags, a `Symbol` for the flag itself and `Level` for which
// flag.
specs: FxHashMap<LintId, LevelAndSource>,
},

Node {
specs: FxHashMap<LintId, LevelAndSource>,
parent: u32,
},
rustc_index::newtype_index! {
#[derive(HashStable)]
pub struct LintStackIndex {
const COMMAND_LINE = 0,
}
}

#[derive(Debug, HashStable)]
pub struct LintSet {
// -A,-W,-D flags, a `Symbol` for the flag itself and `Level` for which
// flag.
pub specs: FxHashMap<LintId, LevelAndSource>,

pub parent: LintStackIndex,
}

impl LintLevelSets {
pub fn new() -> Self {
LintLevelSets { list: Vec::new(), lint_cap: Level::Forbid }
LintLevelSets { list: IndexVec::new(), lint_cap: Level::Forbid }
}

pub fn get_lint_level(
&self,
lint: &'static Lint,
idx: u32,
idx: LintStackIndex,
aux: Option<&FxHashMap<LintId, LevelAndSource>>,
sess: &Session,
) -> LevelAndSource {
Expand Down Expand Up @@ -122,7 +125,7 @@ impl LintLevelSets {
pub fn get_lint_id_level(
&self,
id: LintId,
mut idx: u32,
mut idx: LintStackIndex,
aux: Option<&FxHashMap<LintId, LevelAndSource>>,
) -> (Option<Level>, LintLevelSource) {
if let Some(specs) = aux {
Expand All @@ -131,28 +134,22 @@ impl LintLevelSets {
}
}
loop {
match self.list[idx as usize] {
LintSet::CommandLine { ref specs } => {
if let Some(&(level, src)) = specs.get(&id) {
return (Some(level), src);
}
return (None, LintLevelSource::Default);
}
LintSet::Node { ref specs, parent } => {
if let Some(&(level, src)) = specs.get(&id) {
return (Some(level), src);
}
idx = parent;
}
let LintSet { ref specs, parent } = self.list[idx];
if let Some(&(level, src)) = specs.get(&id) {
return (Some(level), src);
}
if idx == COMMAND_LINE {
return (None, LintLevelSource::Default);
}
idx = parent;
}
}
}

#[derive(Debug)]
pub struct LintLevelMap {
pub sets: LintLevelSets,
pub id_to_set: FxHashMap<HirId, u32>,
pub id_to_set: FxHashMap<HirId, LintStackIndex>,
}

impl LintLevelMap {
Expand Down Expand Up @@ -180,29 +177,7 @@ impl<'a> HashStable<StableHashingContext<'a>> for LintLevelMap {

id_to_set.hash_stable(hcx, hasher);

let LintLevelSets { ref list, lint_cap } = *sets;

lint_cap.hash_stable(hcx, hasher);

hcx.while_hashing_spans(true, |hcx| {
list.len().hash_stable(hcx, hasher);

// We are working under the assumption here that the list of
// lint-sets is built in a deterministic order.
for lint_set in list {
::std::mem::discriminant(lint_set).hash_stable(hcx, hasher);

match *lint_set {
LintSet::CommandLine { ref specs } => {
specs.hash_stable(hcx, hasher);
}
LintSet::Node { ref specs, parent } => {
specs.hash_stable(hcx, hasher);
parent.hash_stable(hcx, hasher);
}
}
}
})
hcx.while_hashing_spans(true, |hcx| sets.hash_stable(hcx, hasher))
}
}

Expand Down

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