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Auto merge of #131481 - nnethercote:rm-GenKillSet, r=cjgillot

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Remove `GenKillAnalysis`

There are two kinds of dataflow analysis in the compiler: `Analysis`, which is the basic kind, and `GenKillAnalysis`, which is a more specialized kind for gen/kill analyses that is intended as an optimization. However, it turns out that `GenKillAnalysis` is actually a  pessimization! It's faster (and much simpler) to do all the gen/kill analyses via `Analysis`. This lets us remove `GenKillAnalysis`, and `GenKillSet`, and a few other things, and also merge `AnalysisDomain` into `Analysis`. The PR removes 500 lines of code and improves performance.

r? `@tmiasko`
This commit is contained in:
bors 2024-10-16 09:45:05 +00:00
commit d829780c4e
17 changed files with 161 additions and 657 deletions
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64
compiler/rustc_borrowck/src/dataflow.rs
View File

@ -1,13 +1,11 @@
use rustc_data_structures::fx::FxIndexMap;
use rustc_data_structures::graph;
use rustc_index::bit_set::BitSet;
use rustc_middle::mir::{
self, BasicBlock, Body, CallReturnPlaces, Location, Place, TerminatorEdges,
};
use rustc_middle::mir::{self, BasicBlock, Body, Location, Place, TerminatorEdges};
use rustc_middle::ty::{RegionVid, TyCtxt};
use rustc_mir_dataflow::fmt::DebugWithContext;
use rustc_mir_dataflow::impls::{EverInitializedPlaces, MaybeUninitializedPlaces};
use rustc_mir_dataflow::{Analysis, AnalysisDomain, Forward, GenKill, Results, ResultsVisitable};
use rustc_mir_dataflow::{Analysis, Forward, GenKill, Results, ResultsVisitable};
use tracing::debug;
use crate::{BorrowSet, PlaceConflictBias, PlaceExt, RegionInferenceContext, places_conflict};
@ -22,9 +20,9 @@ pub(crate) struct BorrowckResults<'a, 'tcx> {
/// The transient state of the dataflow analyses used by the borrow checker.
#[derive(Debug)]
pub(crate) struct BorrowckDomain<'a, 'tcx> {
pub(crate) borrows: <Borrows<'a, 'tcx> as AnalysisDomain<'tcx>>::Domain,
pub(crate) uninits: <MaybeUninitializedPlaces<'a, 'tcx> as AnalysisDomain<'tcx>>::Domain,
pub(crate) ever_inits: <EverInitializedPlaces<'a, 'tcx> as AnalysisDomain<'tcx>>::Domain,
pub(crate) borrows: <Borrows<'a, 'tcx> as Analysis<'tcx>>::Domain,
pub(crate) uninits: <MaybeUninitializedPlaces<'a, 'tcx> as Analysis<'tcx>>::Domain,
pub(crate) ever_inits: <EverInitializedPlaces<'a, 'tcx> as Analysis<'tcx>>::Domain,
}
impl<'a, 'tcx> ResultsVisitable<'tcx> for BorrowckResults<'a, 'tcx> {
@ -427,7 +425,7 @@ pub fn new(
/// That means they went out of a nonlexical scope
fn kill_loans_out_of_scope_at_location(
&self,
trans: &mut impl GenKill<BorrowIndex>,
trans: &mut <Self as Analysis<'tcx>>::Domain,
location: Location,
) {
// NOTE: The state associated with a given `location`
@ -447,7 +445,11 @@ fn kill_loans_out_of_scope_at_location(
}
/// Kill any borrows that conflict with `place`.
fn kill_borrows_on_place(&self, trans: &mut impl GenKill<BorrowIndex>, place: Place<'tcx>) {
fn kill_borrows_on_place(
&self,
trans: &mut <Self as Analysis<'tcx>>::Domain,
place: Place<'tcx>,
) {
debug!("kill_borrows_on_place: place={:?}", place);
let other_borrows_of_local = self
@ -486,7 +488,14 @@ fn kill_borrows_on_place(&self, trans: &mut impl GenKill<BorrowIndex>, place: Pl
}
}
impl<'tcx> rustc_mir_dataflow::AnalysisDomain<'tcx> for Borrows<'_, 'tcx> {
/// Forward dataflow computation of the set of borrows that are in scope at a particular location.
/// - we gen the introduced loans
/// - we kill loans on locals going out of (regular) scope
/// - we kill the loans going out of their region's NLL scope: in NLL terms, the frontier where a
/// region stops containing the CFG points reachable from the issuing location.
/// - we also kill loans of conflicting places when overwriting a shared path: e.g. borrows of
/// `a.b.c` when `a` is overwritten.
impl<'tcx> rustc_mir_dataflow::Analysis<'tcx> for Borrows<'_, 'tcx> {
type Domain = BitSet<BorrowIndex>;
const NAME: &'static str = "borrows";
@ -500,34 +509,19 @@ fn initialize_start_block(&self, _: &mir::Body<'tcx>, _: &mut Self::Domain) {
// no borrows of code region_scopes have been taken prior to
// function execution, so this method has no effect.
}
}
/// Forward dataflow computation of the set of borrows that are in scope at a particular location.
/// - we gen the introduced loans
/// - we kill loans on locals going out of (regular) scope
/// - we kill the loans going out of their region's NLL scope: in NLL terms, the frontier where a
/// region stops containing the CFG points reachable from the issuing location.
/// - we also kill loans of conflicting places when overwriting a shared path: e.g. borrows of
/// `a.b.c` when `a` is overwritten.
impl<'tcx> rustc_mir_dataflow::GenKillAnalysis<'tcx> for Borrows<'_, 'tcx> {
type Idx = BorrowIndex;
fn domain_size(&self, _: &mir::Body<'tcx>) -> usize {
self.borrow_set.len()
}
fn before_statement_effect(
fn apply_before_statement_effect(
&mut self,
trans: &mut impl GenKill<Self::Idx>,
trans: &mut Self::Domain,
_statement: &mir::Statement<'tcx>,
location: Location,
) {
self.kill_loans_out_of_scope_at_location(trans, location);
}
fn statement_effect(
fn apply_statement_effect(
&mut self,
trans: &mut impl GenKill<Self::Idx>,
trans: &mut Self::Domain,
stmt: &mir::Statement<'tcx>,
location: Location,
) {
@ -573,7 +567,7 @@ fn statement_effect(
}
}
fn before_terminator_effect(
fn apply_before_terminator_effect(
&mut self,
trans: &mut Self::Domain,
_terminator: &mir::Terminator<'tcx>,
@ -582,7 +576,7 @@ fn before_terminator_effect(
self.kill_loans_out_of_scope_at_location(trans, location);
}
fn terminator_effect<'mir>(
fn apply_terminator_effect<'mir>(
&mut self,
trans: &mut Self::Domain,
terminator: &'mir mir::Terminator<'tcx>,
@ -599,14 +593,6 @@ fn terminator_effect<'mir>(
}
terminator.edges()
}
fn call_return_effect(
&mut self,
_trans: &mut Self::Domain,
_block: mir::BasicBlock,
_return_places: CallReturnPlaces<'_, 'tcx>,
) {
}
}
impl<C> DebugWithContext<C> for BorrowIndex {}

9
compiler/rustc_const_eval/src/check_consts/resolver.rs
View File

@ -11,7 +11,7 @@
self, BasicBlock, CallReturnPlaces, Local, Location, Statement, StatementKind, TerminatorEdges,
};
use rustc_mir_dataflow::fmt::DebugWithContext;
use rustc_mir_dataflow::{Analysis, AnalysisDomain, JoinSemiLattice};
use rustc_mir_dataflow::{Analysis, JoinSemiLattice};
use super::{ConstCx, Qualif, qualifs};
@ -310,7 +310,7 @@ fn join(&mut self, other: &Self) -> bool {
}
}
impl<'tcx, Q> AnalysisDomain<'tcx> for FlowSensitiveAnalysis<'_, '_, 'tcx, Q>
impl<'tcx, Q> Analysis<'tcx> for FlowSensitiveAnalysis<'_, '_, 'tcx, Q>
where
Q: Qualif,
{
@ -328,12 +328,7 @@ fn bottom_value(&self, body: &mir::Body<'tcx>) -> Self::Domain {
fn initialize_start_block(&self, _body: &mir::Body<'tcx>, state: &mut Self::Domain) {
self.transfer_function(state).initialize_state();
}
}
impl<'tcx, Q> Analysis<'tcx> for FlowSensitiveAnalysis<'_, '_, 'tcx, Q>
where
Q: Qualif,
{
fn apply_statement_effect(
&mut self,
state: &mut Self::Domain,

7
compiler/rustc_middle/src/mir/basic_blocks.rs
View File

@ -26,7 +26,6 @@ pub struct BasicBlocks<'tcx> {
struct Cache {
predecessors: OnceLock<Predecessors>,
switch_sources: OnceLock<SwitchSources>,
is_cyclic: OnceLock<bool>,
reverse_postorder: OnceLock<Vec<BasicBlock>>,
dominators: OnceLock<Dominators<BasicBlock>>,
}
@ -37,12 +36,6 @@ pub fn new(basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>) -> Self {
BasicBlocks { basic_blocks, cache: Cache::default() }
}
/// Returns true if control-flow graph contains a cycle reachable from the `START_BLOCK`.
#[inline]
pub fn is_cfg_cyclic(&self) -> bool {
*self.cache.is_cyclic.get_or_init(|| graph::is_cyclic(self))
}
pub fn dominators(&self) -> &Dominators<BasicBlock> {
self.cache.dominators.get_or_init(|| dominators(self))
}

11
compiler/rustc_mir_dataflow/src/framework/cursor.rs
View File

@ -7,7 +7,6 @@
use rustc_middle::mir::{self, BasicBlock, Location};
use super::{Analysis, Direction, Effect, EffectIndex, Results};
use crate::framework::BitSetExt;
/// Allows random access inspection of the results of a dataflow analysis.
///
@ -221,16 +220,6 @@ pub fn apply_custom_effect(&mut self, f: impl FnOnce(&mut A, &mut A::Domain)) {
}
}
impl<'mir, 'tcx, A> ResultsCursor<'mir, 'tcx, A>
where
A: crate::GenKillAnalysis<'tcx>,
A::Domain: BitSetExt<A::Idx>,
{
pub fn contains(&self, elem: A::Idx) -> bool {
self.get().contains(elem)
}
}
#[derive(Clone, Copy, Debug)]
struct CursorPosition {
block: BasicBlock,

52
compiler/rustc_mir_dataflow/src/framework/direction.rs
View File

@ -5,7 +5,7 @@
};
use super::visitor::{ResultsVisitable, ResultsVisitor};
use super::{Analysis, Effect, EffectIndex, GenKillAnalysis, GenKillSet, SwitchIntTarget};
use super::{Analysis, Effect, EffectIndex, SwitchIntTarget};
pub trait Direction {
const IS_FORWARD: bool;
@ -29,19 +29,10 @@ fn apply_effects_in_block<'mir, 'tcx, A>(
state: &mut A::Domain,
block: BasicBlock,
block_data: &'mir mir::BasicBlockData<'tcx>,
statement_effect: Option<&dyn Fn(BasicBlock, &mut A::Domain)>,
) -> TerminatorEdges<'mir, 'tcx>
where
A: Analysis<'tcx>;
fn gen_kill_statement_effects_in_block<'tcx, A>(
analysis: &mut A,
trans: &mut GenKillSet<A::Idx>,
block: BasicBlock,
block_data: &mir::BasicBlockData<'tcx>,
) where
A: GenKillAnalysis<'tcx>;
fn visit_results_in_block<'mir, 'tcx, D, R>(
state: &mut D,
block: BasicBlock,
@ -73,7 +64,6 @@ fn apply_effects_in_block<'mir, 'tcx, A>(
state: &mut A::Domain,
block: BasicBlock,
block_data: &'mir mir::BasicBlockData<'tcx>,
statement_effect: Option<&dyn Fn(BasicBlock, &mut A::Domain)>,
) -> TerminatorEdges<'mir, 'tcx>
where
A: Analysis<'tcx>,
@ -82,33 +72,14 @@ fn apply_effects_in_block<'mir, 'tcx, A>(
let location = Location { block, statement_index: block_data.statements.len() };
analysis.apply_before_terminator_effect(state, terminator, location);
let edges = analysis.apply_terminator_effect(state, terminator, location);
if let Some(statement_effect) = statement_effect {
statement_effect(block, state)
} else {
for (statement_index, statement) in block_data.statements.iter().enumerate().rev() {
let location = Location { block, statement_index };
analysis.apply_before_statement_effect(state, statement, location);
analysis.apply_statement_effect(state, statement, location);
}
}
edges
}
fn gen_kill_statement_effects_in_block<'tcx, A>(
analysis: &mut A,
trans: &mut GenKillSet<A::Idx>,
block: BasicBlock,
block_data: &mir::BasicBlockData<'tcx>,
) where
A: GenKillAnalysis<'tcx>,
{
for (statement_index, statement) in block_data.statements.iter().enumerate().rev() {
let location = Location { block, statement_index };
analysis.before_statement_effect(trans, statement, location);
analysis.statement_effect(trans, statement, location);
}
}
fn apply_effects_in_range<'tcx, A>(
analysis: &mut A,
state: &mut A::Domain,
@ -330,42 +301,21 @@ fn apply_effects_in_block<'mir, 'tcx, A>(
state: &mut A::Domain,
block: BasicBlock,
block_data: &'mir mir::BasicBlockData<'tcx>,
statement_effect: Option<&dyn Fn(BasicBlock, &mut A::Domain)>,
) -> TerminatorEdges<'mir, 'tcx>
where
A: Analysis<'tcx>,
{
if let Some(statement_effect) = statement_effect {
statement_effect(block, state)
} else {
for (statement_index, statement) in block_data.statements.iter().enumerate() {
let location = Location { block, statement_index };
analysis.apply_before_statement_effect(state, statement, location);
analysis.apply_statement_effect(state, statement, location);
}
}
let terminator = block_data.terminator();
let location = Location { block, statement_index: block_data.statements.len() };
analysis.apply_before_terminator_effect(state, terminator, location);
analysis.apply_terminator_effect(state, terminator, location)
}
fn gen_kill_statement_effects_in_block<'tcx, A>(
analysis: &mut A,
trans: &mut GenKillSet<A::Idx>,
block: BasicBlock,
block_data: &mir::BasicBlockData<'tcx>,
) where
A: GenKillAnalysis<'tcx>,
{
for (statement_index, statement) in block_data.statements.iter().enumerate() {
let location = Location { block, statement_index };
analysis.before_statement_effect(trans, statement, location);
analysis.statement_effect(trans, statement, location);
}
}
fn apply_effects_in_range<'tcx, A>(
analysis: &mut A,
state: &mut A::Domain,

89
compiler/rustc_mir_dataflow/src/framework/engine.rs
View File

@ -5,7 +5,7 @@
use rustc_data_structures::work_queue::WorkQueue;
use rustc_hir::def_id::DefId;
use rustc_index::{Idx, IndexVec};
use rustc_index::IndexVec;
use rustc_middle::bug;
use rustc_middle::mir::{self, BasicBlock, create_dump_file, dump_enabled, traversal};
use rustc_middle::ty::TyCtxt;
@ -16,15 +16,13 @@
use super::fmt::DebugWithContext;
use super::{
Analysis, AnalysisDomain, Direction, GenKill, GenKillAnalysis, GenKillSet, JoinSemiLattice,
ResultsCursor, ResultsVisitor, graphviz, visit_results,
Analysis, Direction, JoinSemiLattice, ResultsCursor, ResultsVisitor, graphviz, visit_results,
};
use crate::errors::{
DuplicateValuesFor, PathMustEndInFilename, RequiresAnArgument, UnknownFormatter,
};
use crate::framework::BitSetExt;
type EntrySets<'tcx, A> = IndexVec<BasicBlock, <A as AnalysisDomain<'tcx>>::Domain>;
type EntrySets<'tcx, A> = IndexVec<BasicBlock, <A as Analysis<'tcx>>::Domain>;
/// A dataflow analysis that has converged to fixpoint.
#[derive(Clone)]
@ -82,53 +80,6 @@ pub struct Engine<'mir, 'tcx, A>
entry_sets: IndexVec<BasicBlock, A::Domain>,
pass_name: Option<&'static str>,
analysis: A,
/// Cached, cumulative transfer functions for each block.
//
// FIXME(ecstaticmorse): This boxed `Fn` trait object is invoked inside a tight loop for
// gen/kill problems on cyclic CFGs. This is not ideal, but it doesn't seem to degrade
// performance in practice. I've tried a few ways to avoid this, but they have downsides. See
// the message for the commit that added this FIXME for more information.
apply_statement_trans_for_block: Option<Box<dyn Fn(BasicBlock, &mut A::Domain)>>,
}
impl<'mir, 'tcx, A, D, T> Engine<'mir, 'tcx, A>
where
A: GenKillAnalysis<'tcx, Idx = T, Domain = D>,
D: Clone + JoinSemiLattice + GenKill<T> + BitSetExt<T>,
T: Idx,
{
/// Creates a new `Engine` to solve a gen-kill dataflow problem.
pub fn new_gen_kill(tcx: TyCtxt<'tcx>, body: &'mir mir::Body<'tcx>, mut analysis: A) -> Self {
// If there are no back-edges in the control-flow graph, we only ever need to apply the
// transfer function for each block exactly once (assuming that we process blocks in RPO).
//
// In this case, there's no need to compute the block transfer functions ahead of time.
if !body.basic_blocks.is_cfg_cyclic() {
return Self::new(tcx, body, analysis, None);
}
// Otherwise, compute and store the cumulative transfer function for each block.
let identity = GenKillSet::identity(analysis.domain_size(body));
let mut trans_for_block = IndexVec::from_elem(identity, &body.basic_blocks);
for (block, block_data) in body.basic_blocks.iter_enumerated() {
let trans = &mut trans_for_block[block];
A::Direction::gen_kill_statement_effects_in_block(
&mut analysis,
trans,
block,
block_data,
);
}
let apply_trans = Box::new(move |bb: BasicBlock, state: &mut A::Domain| {
trans_for_block[bb].apply(state);
});
Self::new(tcx, body, analysis, Some(apply_trans as Box<_>))
}
}
impl<'mir, 'tcx, A, D> Engine<'mir, 'tcx, A>
@ -138,19 +89,7 @@ impl<'mir, 'tcx, A, D> Engine<'mir, 'tcx, A>
{
/// Creates a new `Engine` to solve a dataflow problem with an arbitrary transfer
/// function.
///
/// Gen-kill problems should use `new_gen_kill`, which will coalesce transfer functions for
/// better performance.
pub fn new_generic(tcx: TyCtxt<'tcx>, body: &'mir mir::Body<'tcx>, analysis: A) -> Self {
Self::new(tcx, body, analysis, None)
}
fn new(
tcx: TyCtxt<'tcx>,
body: &'mir mir::Body<'tcx>,
analysis: A,
apply_statement_trans_for_block: Option<Box<dyn Fn(BasicBlock, &mut A::Domain)>>,
) -> Self {
pub(crate) fn new(tcx: TyCtxt<'tcx>, body: &'mir mir::Body<'tcx>, analysis: A) -> Self {
let mut entry_sets =
IndexVec::from_fn_n(|_| analysis.bottom_value(body), body.basic_blocks.len());
analysis.initialize_start_block(body, &mut entry_sets[mir::START_BLOCK]);
@ -160,7 +99,7 @@ fn new(
bug!("`initialize_start_block` is not yet supported for backward dataflow analyses");
}
Engine { analysis, tcx, body, pass_name: None, entry_sets, apply_statement_trans_for_block }
Engine { analysis, tcx, body, pass_name: None, entry_sets }
}
/// Adds an identifier to the graphviz output for this particular run of a dataflow analysis.
@ -177,14 +116,7 @@ pub fn iterate_to_fixpoint(self) -> Results<'tcx, A>
where
A::Domain: DebugWithContext<A>,
{
let Engine {
mut analysis,
body,
mut entry_sets,
tcx,
apply_statement_trans_for_block,
pass_name,
} = self;
let Engine { mut analysis, body, mut entry_sets, tcx, pass_name } = self;
let mut dirty_queue: WorkQueue<BasicBlock> = WorkQueue::with_none(body.basic_blocks.len());
@ -213,13 +145,8 @@ pub fn iterate_to_fixpoint(self) -> Results<'tcx, A>
state.clone_from(&entry_sets[bb]);
// Apply the block transfer function, using the cached one if it exists.
let edges = A::Direction::apply_effects_in_block(
&mut analysis,
&mut state,
bb,
bb_data,
apply_statement_trans_for_block.as_deref(),
);
let edges =
A::Direction::apply_effects_in_block(&mut analysis, &mut state, bb, bb_data);
A::Direction::join_state_into_successors_of(
&mut analysis,

265
compiler/rustc_mir_dataflow/src/framework/mod.rs
View File

@ -1,9 +1,11 @@
//! A framework that can express both [gen-kill] and generic dataflow problems.
//!
//! To use this framework, implement either the [`Analysis`] or the
//! [`GenKillAnalysis`] trait. If your transfer function can be expressed with only gen/kill
//! operations, prefer `GenKillAnalysis` since it will run faster while iterating to fixpoint. The
//! `impls` module contains several examples of gen/kill dataflow analyses.
//! To use this framework, implement the [`Analysis`] trait. There used to be a `GenKillAnalysis`
//! alternative trait for gen-kill analyses that would pre-compute the transfer function for each
//! block. It was intended as an optimization, but it ended up not being any faster than
//! `Analysis`.
//!
//! The `impls` module contains several examples of dataflow analyses.
//!
//! Create an `Engine` for your analysis using the `into_engine` method on the `Analysis` trait,
//! then call `iterate_to_fixpoint`. From there, you can use a `ResultsCursor` to inspect the
@ -87,11 +89,26 @@ fn subtract(&mut self, other: &HybridBitSet<T>) {
}
}
/// Defines the domain of a dataflow problem.
/// A dataflow problem with an arbitrarily complex transfer function.
///
/// This trait specifies the lattice on which this analysis operates (the domain) as well as its
/// initial value at the entry point of each basic block.
pub trait AnalysisDomain<'tcx> {
/// This trait specifies the lattice on which this analysis operates (the domain), its
/// initial value at the entry point of each basic block, and various operations.
///
/// # Convergence
///
/// When implementing this trait it's possible to choose a transfer function such that the analysis
/// does not reach fixpoint. To guarantee convergence, your transfer functions must maintain the
/// following invariant:
///
/// > If the dataflow state **before** some point in the program changes to be greater
/// than the prior state **before** that point, the dataflow state **after** that point must
/// also change to be greater than the prior state **after** that point.
///
/// This invariant guarantees that the dataflow state at a given point in the program increases
/// monotonically until fixpoint is reached. Note that this monotonicity requirement only applies
/// to the same point in the program at different points in time. The dataflow state at a given
/// point in the program may or may not be greater than the state at any preceding point.
pub trait Analysis<'tcx> {
/// The type that holds the dataflow state at any given point in the program.
type Domain: Clone + JoinSemiLattice;
@ -116,25 +133,7 @@ pub trait AnalysisDomain<'tcx> {
// block where control flow could exit the MIR body (e.g., those terminated with `return` or
// `resume`). It's not obvious how to handle `yield` points in coroutines, however.
fn initialize_start_block(&self, body: &mir::Body<'tcx>, state: &mut Self::Domain);
}
/// A dataflow problem with an arbitrarily complex transfer function.
///
/// # Convergence
///
/// When implementing this trait directly (not via [`GenKillAnalysis`]), it's possible to choose a
/// transfer function such that the analysis does not reach fixpoint. To guarantee convergence,
/// your transfer functions must maintain the following invariant:
///
/// > If the dataflow state **before** some point in the program changes to be greater
/// than the prior state **before** that point, the dataflow state **after** that point must
/// also change to be greater than the prior state **after** that point.
///
/// This invariant guarantees that the dataflow state at a given point in the program increases
/// monotonically until fixpoint is reached. Note that this monotonicity requirement only applies
/// to the same point in the program at different points in time. The dataflow state at a given
/// point in the program may or may not be greater than the state at any preceding point.
pub trait Analysis<'tcx>: AnalysisDomain<'tcx> {
/// Updates the current dataflow state with the effect of evaluating a statement.
fn apply_statement_effect(
&mut self,
@ -165,10 +164,12 @@ fn apply_before_statement_effect(
/// initialized here.
fn apply_terminator_effect<'mir>(
&mut self,
state: &mut Self::Domain,
_state: &mut Self::Domain,
terminator: &'mir mir::Terminator<'tcx>,
location: Location,
) -> TerminatorEdges<'mir, 'tcx>;
_location: Location,
) -> TerminatorEdges<'mir, 'tcx> {
terminator.edges()
}
/// Updates the current dataflow state with an effect that occurs immediately *before* the
/// given terminator.
@ -193,10 +194,11 @@ fn apply_before_terminator_effect(
/// edges.
fn apply_call_return_effect(
&mut self,
state: &mut Self::Domain,
block: BasicBlock,
return_places: CallReturnPlaces<'_, 'tcx>,
);
_state: &mut Self::Domain,
_block: BasicBlock,
_return_places: CallReturnPlaces<'_, 'tcx>,
) {
}
/// Updates the current dataflow state with the effect of taking a particular branch in a
/// `SwitchInt` terminator.
@ -223,9 +225,7 @@ fn apply_switch_int_edge_effects(
/// Creates an `Engine` to find the fixpoint for this dataflow problem.
///
/// You shouldn't need to override this outside this module, since the combination of the
/// default impl and the one for all `A: GenKillAnalysis` will do the right thing.
/// Its purpose is to enable method chaining like so:
/// You shouldn't need to override this. Its purpose is to enable method chaining like so:
///
/// ```ignore (cross-crate-imports)
/// let results = MyAnalysis::new(tcx, body)
@ -242,164 +242,11 @@ fn into_engine<'mir>(
where
Self: Sized,
{
Engine::new_generic(tcx, body, self)
}
}
/// A gen/kill dataflow problem.
///
/// Each method in this trait has a corresponding one in `Analysis`. However, the first two methods
/// here only allow modification of the dataflow state via "gen" and "kill" operations. By defining
/// transfer functions for each statement in this way, the transfer function for an entire basic
/// block can be computed efficiently. The remaining methods match up with `Analysis` exactly.
///
/// `Analysis` is automatically implemented for all implementers of `GenKillAnalysis` via a blanket
/// impl below.
pub trait GenKillAnalysis<'tcx>: Analysis<'tcx> {
type Idx: Idx;
fn domain_size(&self, body: &mir::Body<'tcx>) -> usize;
/// See `Analysis::apply_statement_effect`. Note how the second arg differs.
fn statement_effect(
&mut self,
trans: &mut impl GenKill<Self::Idx>,
statement: &mir::Statement<'tcx>,
location: Location,
);
/// See `Analysis::apply_before_statement_effect`. Note how the second arg
/// differs.
fn before_statement_effect(
&mut self,
_trans: &mut impl GenKill<Self::Idx>,
_statement: &mir::Statement<'tcx>,
_location: Location,
) {
}
/// See `Analysis::apply_terminator_effect`.
fn terminator_effect<'mir>(
&mut self,
trans: &mut Self::Domain,
terminator: &'mir mir::Terminator<'tcx>,
location: Location,
) -> TerminatorEdges<'mir, 'tcx>;
/// See `Analysis::apply_before_terminator_effect`.
fn before_terminator_effect(
&mut self,
_trans: &mut Self::Domain,
_terminator: &mir::Terminator<'tcx>,
_location: Location,
) {
}
/* Edge-specific effects */
/// See `Analysis::apply_call_return_effect`.
fn call_return_effect(
&mut self,
trans: &mut Self::Domain,
block: BasicBlock,
return_places: CallReturnPlaces<'_, 'tcx>,
);
/// See `Analysis::apply_switch_int_edge_effects`.
fn switch_int_edge_effects<G: GenKill<Self::Idx>>(
&mut self,
_block: BasicBlock,
_discr: &mir::Operand<'tcx>,
_edge_effects: &mut impl SwitchIntEdgeEffects<G>,
) {
}
}
// Blanket impl: any impl of `GenKillAnalysis` automatically impls `Analysis`.
impl<'tcx, A> Analysis<'tcx> for A
where
A: GenKillAnalysis<'tcx>,
A::Domain: GenKill<A::Idx> + BitSetExt<A::Idx>,
{
fn apply_statement_effect(
&mut self,
state: &mut A::Domain,
statement: &mir::Statement<'tcx>,
location: Location,
) {
self.statement_effect(state, statement, location);
}
fn apply_before_statement_effect(
&mut self,
state: &mut A::Domain,
statement: &mir::Statement<'tcx>,
location: Location,
) {
self.before_statement_effect(state, statement, location);
}
fn apply_terminator_effect<'mir>(
&mut self,
state: &mut A::Domain,
terminator: &'mir mir::Terminator<'tcx>,
location: Location,
) -> TerminatorEdges<'mir, 'tcx> {
self.terminator_effect(state, terminator, location)
}
fn apply_before_terminator_effect(
&mut self,
state: &mut A::Domain,
terminator: &mir::Terminator<'tcx>,
location: Location,
) {
self.before_terminator_effect(state, terminator, location);
}
/* Edge-specific effects */
fn apply_call_return_effect(
&mut self,
state: &mut A::Domain,
block: BasicBlock,
return_places: CallReturnPlaces<'_, 'tcx>,
) {
self.call_return_effect(state, block, return_places);
}
fn apply_switch_int_edge_effects(
&mut self,
block: BasicBlock,
discr: &mir::Operand<'tcx>,
edge_effects: &mut impl SwitchIntEdgeEffects<A::Domain>,
) {
self.switch_int_edge_effects(block, discr, edge_effects);
}
/* Extension methods */
#[inline]
fn into_engine<'mir>(
self,
tcx: TyCtxt<'tcx>,
body: &'mir mir::Body<'tcx>,
) -> Engine<'mir, 'tcx, Self>
where
Self: Sized,
{
Engine::new_gen_kill(tcx, body, self)
Engine::new(tcx, body, self)
}
}
/// The legal operations for a transfer function in a gen/kill problem.
///
/// This abstraction exists because there are two different contexts in which we call the methods in
/// `GenKillAnalysis`. Sometimes we need to store a single transfer function that can be efficiently
/// applied multiple times, such as when computing the cumulative transfer function for each block.
/// These cases require a `GenKillSet`, which in turn requires two `BitSet`s of storage. Oftentimes,
/// however, we only need to apply an effect once. In *these* cases, it is more efficient to pass the
/// `BitSet` representing the state vector directly into the `*_effect` methods as opposed to
/// building up a `GenKillSet` and then throwing it away.
pub trait GenKill<T> {
/// Inserts `elem` into the state vector.
fn gen_(&mut self, elem: T);
@ -422,44 +269,6 @@ fn kill_all(&mut self, elems: impl IntoIterator<Item = T>) {
}
}
/// Stores a transfer function for a gen/kill problem.
///
/// Calling `gen_`/`kill` on a `GenKillSet` will "build up" a transfer function so that it can be
/// applied multiple times efficiently. When there are multiple calls to `gen_` and/or `kill` for
/// the same element, the most recent one takes precedence.
#[derive(Clone)]
pub struct GenKillSet<T> {
gen_: HybridBitSet<T>,
kill: HybridBitSet<T>,
}
impl<T: Idx> GenKillSet<T> {
/// Creates a new transfer function that will leave the dataflow state unchanged.
pub fn identity(universe: usize) -> Self {
GenKillSet {
gen_: HybridBitSet::new_empty(universe),
kill: HybridBitSet::new_empty(universe),
}
}
pub fn apply(&self, state: &mut impl BitSetExt<T>) {
state.union(&self.gen_);
state.subtract(&self.kill);
}
}
impl<T: Idx> GenKill<T> for GenKillSet<T> {
fn gen_(&mut self, elem: T) {
self.gen_.insert(elem);
self.kill.remove(elem);
}
fn kill(&mut self, elem: T) {
self.kill.insert(elem);
self.gen_.remove(elem);
}
}
impl<T: Idx> GenKill<T> for BitSet<T> {
fn gen_(&mut self, elem: T) {
self.insert(elem);

12
compiler/rustc_mir_dataflow/src/framework/tests.rs
View File

@ -154,7 +154,7 @@ fn expected_state_at_target(&self, target: SeekTarget) -> BitSet<usize> {
}
}
impl<'tcx, D: Direction> AnalysisDomain<'tcx> for MockAnalysis<'tcx, D> {
impl<'tcx, D: Direction> Analysis<'tcx> for MockAnalysis<'tcx, D> {
type Domain = BitSet<usize>;
type Direction = D;
@ -167,9 +167,7 @@ fn bottom_value(&self, body: &mir::Body<'tcx>) -> Self::Domain {
fn initialize_start_block(&self, _: &mir::Body<'tcx>, _: &mut Self::Domain) {
unimplemented!("This is never called since `MockAnalysis` is never iterated to fixpoint");
}
}
impl<'tcx, D: Direction> Analysis<'tcx> for MockAnalysis<'tcx, D> {
fn apply_statement_effect(
&mut self,
state: &mut Self::Domain,
@ -210,14 +208,6 @@ fn apply_before_terminator_effect(
let idx = self.effect(Effect::Before.at_index(location.statement_index));
assert!(state.insert(idx));
}
fn apply_call_return_effect(
&mut self,
_state: &mut Self::Domain,
_block: BasicBlock,
_return_places: CallReturnPlaces<'_, 'tcx>,
) {
}
}
#[derive(Clone, Copy, Debug, PartialEq, Eq)]

26
compiler/rustc_mir_dataflow/src/impls/borrowed_locals.rs
View File

@ -2,7 +2,7 @@
use rustc_middle::mir::visit::Visitor;
use rustc_middle::mir::*;
use crate::{AnalysisDomain, GenKill, GenKillAnalysis};
use crate::{Analysis, GenKill};
/// A dataflow analysis that tracks whether a pointer or reference could possibly exist that points
/// to a given local. This analysis ignores fake borrows, so it should not be used by
@ -20,7 +20,7 @@ pub(super) fn transfer_function<'a, T>(&'a self, trans: &'a mut T) -> TransferFu
}
}
impl<'tcx> AnalysisDomain<'tcx> for MaybeBorrowedLocals {
impl<'tcx> Analysis<'tcx> for MaybeBorrowedLocals {
type Domain = BitSet<Local>;
const NAME: &'static str = "maybe_borrowed_locals";
@ -32,25 +32,17 @@ fn bottom_value(&self, body: &Body<'tcx>) -> Self::Domain {
fn initialize_start_block(&self, _: &Body<'tcx>, _: &mut Self::Domain) {
// No locals are aliased on function entry
}
}
impl<'tcx> GenKillAnalysis<'tcx> for MaybeBorrowedLocals {
type Idx = Local;
fn domain_size(&self, body: &Body<'tcx>) -> usize {
body.local_decls.len()
}
fn statement_effect(
fn apply_statement_effect(
&mut self,
trans: &mut impl GenKill<Self::Idx>,
trans: &mut Self::Domain,
statement: &Statement<'tcx>,
location: Location,
) {
self.transfer_function(trans).visit_statement(statement, location);
}
fn terminator_effect<'mir>(
fn apply_terminator_effect<'mir>(
&mut self,
trans: &mut Self::Domain,
terminator: &'mir Terminator<'tcx>,
@ -59,14 +51,6 @@ fn terminator_effect<'mir>(
self.transfer_function(trans).visit_terminator(terminator, location);
terminator.edges()
}
fn call_return_effect(
&mut self,
_trans: &mut Self::Domain,
_block: BasicBlock,
_return_places: CallReturnPlaces<'_, 'tcx>,
) {
}
}
/// A `Visitor` that defines the transfer function for `MaybeBorrowedLocals`.

91
compiler/rustc_mir_dataflow/src/impls/initialized.rs
View File

@ -11,9 +11,8 @@
use crate::framework::SwitchIntEdgeEffects;
use crate::move_paths::{HasMoveData, InitIndex, InitKind, LookupResult, MoveData, MovePathIndex};
use crate::{
AnalysisDomain, GenKill, GenKillAnalysis, MaybeReachable, drop_flag_effects,
drop_flag_effects_for_function_entry, drop_flag_effects_for_location, lattice,
on_all_children_bits, on_lookup_result_bits,
Analysis, GenKill, MaybeReachable, drop_flag_effects, drop_flag_effects_for_function_entry,
drop_flag_effects_for_location, lattice, on_all_children_bits, on_lookup_result_bits,
};
/// `MaybeInitializedPlaces` tracks all places that might be
@ -270,7 +269,7 @@ fn move_data(&self) -> &MoveData<'tcx> {
impl<'a, 'tcx> MaybeInitializedPlaces<'a, 'tcx> {
fn update_bits(
trans: &mut impl GenKill<MovePathIndex>,
trans: &mut <Self as Analysis<'tcx>>::Domain,
path: MovePathIndex,
state: DropFlagState,
) {
@ -283,7 +282,7 @@ fn update_bits(
impl<'tcx> MaybeUninitializedPlaces<'_, 'tcx> {
fn update_bits(
trans: &mut impl GenKill<MovePathIndex>,
trans: &mut <Self as Analysis<'tcx>>::Domain,
path: MovePathIndex,
state: DropFlagState,
) {
@ -296,7 +295,7 @@ fn update_bits(
impl<'a, 'tcx> DefinitelyInitializedPlaces<'a, 'tcx> {
fn update_bits(
trans: &mut impl GenKill<MovePathIndex>,
trans: &mut <Self as Analysis<'tcx>>::Domain,
path: MovePathIndex,
state: DropFlagState,
) {
@ -307,7 +306,7 @@ fn update_bits(
}
}
impl<'tcx> AnalysisDomain<'tcx> for MaybeInitializedPlaces<'_, 'tcx> {
impl<'tcx> Analysis<'tcx> for MaybeInitializedPlaces<'_, 'tcx> {
/// There can be many more `MovePathIndex` than there are locals in a MIR body.
/// We use a chunked bitset to avoid paying too high a memory footprint.
type Domain = MaybeReachable<ChunkedBitSet<MovePathIndex>>;
@ -327,18 +326,10 @@ fn initialize_start_block(&self, _: &mir::Body<'tcx>, state: &mut Self::Domain)
state.gen_(path);
});
}
}
impl<'tcx> GenKillAnalysis<'tcx> for MaybeInitializedPlaces<'_, 'tcx> {
type Idx = MovePathIndex;
fn domain_size(&self, _: &Body<'tcx>) -> usize {
self.move_data().move_paths.len()
}
fn statement_effect(
fn apply_statement_effect(
&mut self,
trans: &mut impl GenKill<Self::Idx>,
trans: &mut Self::Domain,
statement: &mir::Statement<'tcx>,
location: Location,
) {
@ -360,7 +351,7 @@ fn statement_effect(
}
}
fn terminator_effect<'mir>(
fn apply_terminator_effect<'mir>(
&mut self,
state: &mut Self::Domain,
terminator: &'mir mir::Terminator<'tcx>,
@ -380,7 +371,7 @@ fn terminator_effect<'mir>(
edges
}
fn call_return_effect(
fn apply_call_return_effect(
&mut self,
trans: &mut Self::Domain,
_block: mir::BasicBlock,
@ -399,11 +390,11 @@ fn call_return_effect(
});
}
fn switch_int_edge_effects<G: GenKill<Self::Idx>>(
fn apply_switch_int_edge_effects(
&mut self,
block: mir::BasicBlock,
discr: &mir::Operand<'tcx>,
edge_effects: &mut impl SwitchIntEdgeEffects<G>,
edge_effects: &mut impl SwitchIntEdgeEffects<Self::Domain>,
) {
if !self.tcx.sess.opts.unstable_opts.precise_enum_drop_elaboration {
return;
@ -442,7 +433,7 @@ fn switch_int_edge_effects<G: GenKill<Self::Idx>>(
}
}
impl<'tcx> AnalysisDomain<'tcx> for MaybeUninitializedPlaces<'_, 'tcx> {
impl<'tcx> Analysis<'tcx> for MaybeUninitializedPlaces<'_, 'tcx> {
/// There can be many more `MovePathIndex` than there are locals in a MIR body.
/// We use a chunked bitset to avoid paying too high a memory footprint.
type Domain = ChunkedBitSet<MovePathIndex>;
@ -464,18 +455,10 @@ fn initialize_start_block(&self, _: &mir::Body<'tcx>, state: &mut Self::Domain)
state.remove(path);
});
}
}
impl<'tcx> GenKillAnalysis<'tcx> for MaybeUninitializedPlaces<'_, 'tcx> {
type Idx = MovePathIndex;
fn domain_size(&self, _: &Body<'tcx>) -> usize {
self.move_data().move_paths.len()
}
fn statement_effect(
fn apply_statement_effect(
&mut self,
trans: &mut impl GenKill<Self::Idx>,
trans: &mut Self::Domain,
_statement: &mir::Statement<'tcx>,
location: Location,
) {
@ -487,7 +470,7 @@ fn statement_effect(
// mutable borrow occurs. Places cannot become uninitialized through a mutable reference.
}
fn terminator_effect<'mir>(
fn apply_terminator_effect<'mir>(
&mut self,
trans: &mut Self::Domain,
terminator: &'mir mir::Terminator<'tcx>,
@ -505,7 +488,7 @@ fn terminator_effect<'mir>(
}
}
fn call_return_effect(
fn apply_call_return_effect(
&mut self,
trans: &mut Self::Domain,
_block: mir::BasicBlock,
@ -524,11 +507,11 @@ fn call_return_effect(
});
}
fn switch_int_edge_effects<G: GenKill<Self::Idx>>(
fn apply_switch_int_edge_effects(
&mut self,
block: mir::BasicBlock,
discr: &mir::Operand<'tcx>,
edge_effects: &mut impl SwitchIntEdgeEffects<G>,
edge_effects: &mut impl SwitchIntEdgeEffects<Self::Domain>,
) {
if !self.tcx.sess.opts.unstable_opts.precise_enum_drop_elaboration {
return;
@ -571,7 +554,7 @@ fn switch_int_edge_effects<G: GenKill<Self::Idx>>(
}
}
impl<'a, 'tcx> AnalysisDomain<'tcx> for DefinitelyInitializedPlaces<'a, 'tcx> {
impl<'a, 'tcx> Analysis<'tcx> for DefinitelyInitializedPlaces<'a, 'tcx> {
/// Use set intersection as the join operator.
type Domain = lattice::Dual<BitSet<MovePathIndex>>;
@ -591,18 +574,10 @@ fn initialize_start_block(&self, _: &mir::Body<'tcx>, state: &mut Self::Domain)
state.0.insert(path);
});
}
}
impl<'tcx> GenKillAnalysis<'tcx> for DefinitelyInitializedPlaces<'_, 'tcx> {
type Idx = MovePathIndex;
fn domain_size(&self, _: &Body<'tcx>) -> usize {
self.move_data().move_paths.len()
}
fn statement_effect(
fn apply_statement_effect(
&mut self,
trans: &mut impl GenKill<Self::Idx>,
trans: &mut Self::Domain,
_statement: &mir::Statement<'tcx>,
location: Location,
) {
@ -611,7 +586,7 @@ fn statement_effect(
})
}
fn terminator_effect<'mir>(
fn apply_terminator_effect<'mir>(
&mut self,
trans: &mut Self::Domain,
terminator: &'mir mir::Terminator<'tcx>,
@ -623,7 +598,7 @@ fn terminator_effect<'mir>(
terminator.edges()
}
fn call_return_effect(
fn apply_call_return_effect(
&mut self,
trans: &mut Self::Domain,
_block: mir::BasicBlock,
@ -643,7 +618,7 @@ fn call_return_effect(
}
}
impl<'tcx> AnalysisDomain<'tcx> for EverInitializedPlaces<'_, 'tcx> {
impl<'tcx> Analysis<'tcx> for EverInitializedPlaces<'_, 'tcx> {
/// There can be many more `InitIndex` than there are locals in a MIR body.
/// We use a chunked bitset to avoid paying too high a memory footprint.
type Domain = ChunkedBitSet<InitIndex>;
@ -660,19 +635,11 @@ fn initialize_start_block(&self, body: &mir::Body<'tcx>, state: &mut Self::Domai
state.insert(InitIndex::new(arg_init));
}
}
}
impl<'tcx> GenKillAnalysis<'tcx> for EverInitializedPlaces<'_, 'tcx> {
type Idx = InitIndex;
fn domain_size(&self, _: &Body<'tcx>) -> usize {
self.move_data().inits.len()
}
#[instrument(skip(self, trans), level = "debug")]
fn statement_effect(
fn apply_statement_effect(
&mut self,
trans: &mut impl GenKill<Self::Idx>,
trans: &mut Self::Domain,
stmt: &mir::Statement<'tcx>,
location: Location,
) {
@ -698,7 +665,7 @@ fn statement_effect(
}
#[instrument(skip(self, trans, terminator), level = "debug")]
fn terminator_effect<'mir>(
fn apply_terminator_effect<'mir>(
&mut self,
trans: &mut Self::Domain,
terminator: &'mir mir::Terminator<'tcx>,
@ -720,7 +687,7 @@ fn terminator_effect<'mir>(
terminator.edges()
}
fn call_return_effect(
fn apply_call_return_effect(
&mut self,
trans: &mut Self::Domain,
block: mir::BasicBlock,

48
compiler/rustc_mir_dataflow/src/impls/liveness.rs
View File

@ -4,7 +4,7 @@
self, CallReturnPlaces, Local, Location, Place, StatementKind, TerminatorEdges,
};
use crate::{Analysis, AnalysisDomain, Backward, GenKill, GenKillAnalysis};
use crate::{Analysis, Backward, GenKill};
/// A [live-variable dataflow analysis][liveness].
///
@ -25,7 +25,7 @@
/// [liveness]: https://en.wikipedia.org/wiki/Live_variable_analysis
pub struct MaybeLiveLocals;
impl<'tcx> AnalysisDomain<'tcx> for MaybeLiveLocals {
impl<'tcx> Analysis<'tcx> for MaybeLiveLocals {
type Domain = BitSet<Local>;
type Direction = Backward;
@ -39,25 +39,17 @@ fn bottom_value(&self, body: &mir::Body<'tcx>) -> Self::Domain {
fn initialize_start_block(&self, _: &mir::Body<'tcx>, _: &mut Self::Domain) {
// No variables are live until we observe a use
}
}
impl<'tcx> GenKillAnalysis<'tcx> for MaybeLiveLocals {
type Idx = Local;
fn domain_size(&self, body: &mir::Body<'tcx>) -> usize {
body.local_decls.len()
}
fn statement_effect(
fn apply_statement_effect(
&mut self,
trans: &mut impl GenKill<Self::Idx>,
trans: &mut Self::Domain,
statement: &mir::Statement<'tcx>,
location: Location,
) {
TransferFunction(trans).visit_statement(statement, location);
}
fn terminator_effect<'mir>(
fn apply_terminator_effect<'mir>(
&mut self,
trans: &mut Self::Domain,
terminator: &'mir mir::Terminator<'tcx>,
@ -67,7 +59,7 @@ fn terminator_effect<'mir>(
terminator.edges()
}
fn call_return_effect(
fn apply_call_return_effect(
&mut self,
trans: &mut Self::Domain,
_block: mir::BasicBlock,
@ -89,12 +81,9 @@ fn call_return_effect(
}
}
pub struct TransferFunction<'a, T>(pub &'a mut T);
pub struct TransferFunction<'a>(pub &'a mut BitSet<Local>);
impl<'tcx, T> Visitor<'tcx> for TransferFunction<'_, T>
where
T: GenKill<Local>,
{
impl<'tcx> Visitor<'tcx> for TransferFunction<'_> {
fn visit_place(&mut self, place: &mir::Place<'tcx>, context: PlaceContext, location: Location) {
if let PlaceContext::MutatingUse(MutatingUseContext::Yield) = context {
// The resume place is evaluated and assigned to only after coroutine resumes, so its
@ -108,10 +97,10 @@ fn visit_place(&mut self, place: &mir::Place<'tcx>, context: PlaceContext, locat
MutatingUseContext::Call | MutatingUseContext::AsmOutput,
) = context
{
// For the associated terminators, this is only a `Def` when the terminator returns
// "successfully." As such, we handle this case separately in `call_return_effect`
// above. However, if the place looks like `*_5`, this is still unconditionally a use of
// `_5`.
// For the associated terminators, this is only a `Def` when the terminator
// returns "successfully." As such, we handle this case separately in
// `call_return_effect` above. However, if the place looks like `*_5`, this is
// still unconditionally a use of `_5`.
} else {
self.0.kill(place.local);
}
@ -128,12 +117,9 @@ fn visit_local(&mut self, local: Local, context: PlaceContext, _: Location) {
}
}
struct YieldResumeEffect<'a, T>(&'a mut T);
struct YieldResumeEffect<'a>(&'a mut BitSet<Local>);
impl<'tcx, T> Visitor<'tcx> for YieldResumeEffect<'_, T>
where
T: GenKill<Local>,
{
impl<'tcx> Visitor<'tcx> for YieldResumeEffect<'_> {
fn visit_place(&mut self, place: &mir::Place<'tcx>, context: PlaceContext, location: Location) {
DefUse::apply(self.0, *place, context);
self.visit_projection(place.as_ref(), context, location);
@ -151,7 +137,7 @@ enum DefUse {
}
impl DefUse {
fn apply(trans: &mut impl GenKill<Local>, place: Place<'_>, context: PlaceContext) {
fn apply(trans: &mut BitSet<Local>, place: Place<'_>, context: PlaceContext) {
match DefUse::for_place(place, context) {
Some(DefUse::Def) => trans.kill(place.local),
Some(DefUse::Use) => trans.gen_(place.local),
@ -231,7 +217,7 @@ pub fn new(always_live: &'a BitSet<Local>) -> Self {
}
}
impl<'a, 'tcx> AnalysisDomain<'tcx> for MaybeTransitiveLiveLocals<'a> {
impl<'a, 'tcx> Analysis<'tcx> for MaybeTransitiveLiveLocals<'a> {
type Domain = BitSet<Local>;
type Direction = Backward;
@ -245,9 +231,7 @@ fn bottom_value(&self, body: &mir::Body<'tcx>) -> Self::Domain {
fn initialize_start_block(&self, _: &mir::Body<'tcx>, _: &mut Self::Domain) {
// No variables are live until we observe a use
}
}
impl<'a, 'tcx> Analysis<'tcx> for MaybeTransitiveLiveLocals<'a> {
fn apply_statement_effect(
&mut self,
trans: &mut Self::Domain,

107
compiler/rustc_mir_dataflow/src/impls/storage_liveness.rs
View File

@ -5,7 +5,7 @@
use rustc_middle::mir::*;
use super::MaybeBorrowedLocals;
use crate::{GenKill, ResultsCursor};
use crate::{Analysis, GenKill, ResultsCursor};
pub struct MaybeStorageLive<'a> {
always_live_locals: Cow<'a, BitSet<Local>>,
@ -17,7 +17,7 @@ pub fn new(always_live_locals: Cow<'a, BitSet<Local>>) -> Self {
}
}
impl<'a, 'tcx> crate::AnalysisDomain<'tcx> for MaybeStorageLive<'a> {
impl<'a, 'tcx> Analysis<'tcx> for MaybeStorageLive<'a> {
type Domain = BitSet<Local>;
const NAME: &'static str = "maybe_storage_live";
@ -37,18 +37,10 @@ fn initialize_start_block(&self, body: &Body<'tcx>, on_entry: &mut Self::Domain)
on_entry.insert(arg);
}
}
}
impl<'a, 'tcx> crate::GenKillAnalysis<'tcx> for MaybeStorageLive<'a> {
type Idx = Local;
fn domain_size(&self, body: &Body<'tcx>) -> usize {
body.local_decls.len()
}
fn statement_effect(
fn apply_statement_effect(
&mut self,
trans: &mut impl GenKill<Self::Idx>,
trans: &mut Self::Domain,
stmt: &Statement<'tcx>,
_: Location,
) {
@ -58,25 +50,6 @@ fn statement_effect(
_ => (),
}
}
fn terminator_effect<'mir>(
&mut self,
_trans: &mut Self::Domain,
terminator: &'mir Terminator<'tcx>,
_: Location,
) -> TerminatorEdges<'mir, 'tcx> {
// Terminators have no effect
terminator.edges()
}
fn call_return_effect(
&mut self,
_trans: &mut Self::Domain,
_block: BasicBlock,
_return_places: CallReturnPlaces<'_, 'tcx>,
) {
// Nothing to do when a call returns successfully
}
}
pub struct MaybeStorageDead<'a> {
@ -89,7 +62,7 @@ pub fn new(always_live_locals: Cow<'a, BitSet<Local>>) -> Self {
}
}
impl<'a, 'tcx> crate::AnalysisDomain<'tcx> for MaybeStorageDead<'a> {
impl<'a, 'tcx> Analysis<'tcx> for MaybeStorageDead<'a> {
type Domain = BitSet<Local>;
const NAME: &'static str = "maybe_storage_dead";
@ -108,18 +81,10 @@ fn initialize_start_block(&self, body: &Body<'tcx>, on_entry: &mut Self::Domain)
}
}
}
}
impl<'a, 'tcx> crate::GenKillAnalysis<'tcx> for MaybeStorageDead<'a> {
type Idx = Local;
fn domain_size(&self, body: &Body<'tcx>) -> usize {
body.local_decls.len()
}
fn statement_effect(
fn apply_statement_effect(
&mut self,
trans: &mut impl GenKill<Self::Idx>,
trans: &mut Self::Domain,
stmt: &Statement<'tcx>,
_: Location,
) {
@ -129,25 +94,6 @@ fn statement_effect(
_ => (),
}
}
fn terminator_effect<'mir>(
&mut self,
_: &mut Self::Domain,
terminator: &'mir Terminator<'tcx>,
_: Location,
) -> TerminatorEdges<'mir, 'tcx> {
// Terminators have no effect
terminator.edges()
}
fn call_return_effect(
&mut self,
_trans: &mut Self::Domain,
_block: BasicBlock,
_return_places: CallReturnPlaces<'_, 'tcx>,
) {
// Nothing to do when a call returns successfully
}
}
type BorrowedLocalsResults<'mir, 'tcx> = ResultsCursor<'mir, 'tcx, MaybeBorrowedLocals>;
@ -164,7 +110,7 @@ pub fn new(borrowed_locals: BorrowedLocalsResults<'mir, 'tcx>) -> Self {
}
}
impl<'tcx> crate::AnalysisDomain<'tcx> for MaybeRequiresStorage<'_, 'tcx> {
impl<'tcx> Analysis<'tcx> for MaybeRequiresStorage<'_, 'tcx> {
type Domain = BitSet<Local>;
const NAME: &'static str = "requires_storage";
@ -181,23 +127,15 @@ fn initialize_start_block(&self, body: &Body<'tcx>, on_entry: &mut Self::Domain)
on_entry.insert(arg);
}
}
}
impl<'tcx> crate::GenKillAnalysis<'tcx> for MaybeRequiresStorage<'_, 'tcx> {
type Idx = Local;
fn domain_size(&self, body: &Body<'tcx>) -> usize {
body.local_decls.len()
}
fn before_statement_effect(
fn apply_before_statement_effect(
&mut self,
trans: &mut impl GenKill<Self::Idx>,
trans: &mut Self::Domain,
stmt: &Statement<'tcx>,
loc: Location,
) {
// If a place is borrowed in a statement, it needs storage for that statement.
self.borrowed_locals.mut_analysis().statement_effect(trans, stmt, loc);
self.borrowed_locals.mut_analysis().apply_statement_effect(trans, stmt, loc);
match &stmt.kind {
StatementKind::StorageDead(l) => trans.kill(*l),
@ -223,9 +161,9 @@ fn before_statement_effect(
}
}
fn statement_effect(
fn apply_statement_effect(
&mut self,
trans: &mut impl GenKill<Self::Idx>,
trans: &mut Self::Domain,
_: &Statement<'tcx>,
loc: Location,
) {
@ -234,7 +172,7 @@ fn statement_effect(
self.check_for_move(trans, loc);
}
fn before_terminator_effect(
fn apply_before_terminator_effect(
&mut self,
trans: &mut Self::Domain,
terminator: &Terminator<'tcx>,
@ -292,7 +230,7 @@ fn before_terminator_effect(
}
}
fn terminator_effect<'t>(
fn apply_terminator_effect<'t>(
&mut self,
trans: &mut Self::Domain,
terminator: &'t Terminator<'tcx>,
@ -333,7 +271,7 @@ fn terminator_effect<'t>(
terminator.edges()
}
fn call_return_effect(
fn apply_call_return_effect(
&mut self,
trans: &mut Self::Domain,
_block: BasicBlock,
@ -345,26 +283,23 @@ fn call_return_effect(
impl<'tcx> MaybeRequiresStorage<'_, 'tcx> {
/// Kill locals that are fully moved and have not been borrowed.
fn check_for_move(&mut self, trans: &mut impl GenKill<Local>, loc: Location) {
fn check_for_move(&mut self, trans: &mut <Self as Analysis<'tcx>>::Domain, loc: Location) {
let body = self.borrowed_locals.body();
let mut visitor = MoveVisitor { trans, borrowed_locals: &mut self.borrowed_locals };
visitor.visit_location(body, loc);
}
}
struct MoveVisitor<'a, 'mir, 'tcx, T> {
struct MoveVisitor<'a, 'mir, 'tcx> {
borrowed_locals: &'a mut BorrowedLocalsResults<'mir, 'tcx>,
trans: &'a mut T,
trans: &'a mut BitSet<Local>,
}
impl<'tcx, T> Visitor<'tcx> for MoveVisitor<'_, '_, 'tcx, T>
where
T: GenKill<Local>,
{
impl<'tcx> Visitor<'tcx> for MoveVisitor<'_, '_, 'tcx> {
fn visit_local(&mut self, local: Local, context: PlaceContext, loc: Location) {
if PlaceContext::NonMutatingUse(NonMutatingUseContext::Move) == context {
self.borrowed_locals.seek_before_primary_effect(loc);
if !self.borrowed_locals.contains(local) {
if !self.borrowed_locals.get().contains(local) {
self.trans.kill(local);
}
}

6
compiler/rustc_mir_dataflow/src/lib.rs
View File

@ -18,9 +18,9 @@
move_path_children_matching, on_all_children_bits, on_lookup_result_bits,
};
pub use self::framework::{
Analysis, AnalysisDomain, Backward, Direction, Engine, Forward, GenKill, GenKillAnalysis,
JoinSemiLattice, MaybeReachable, Results, ResultsCursor, ResultsVisitable, ResultsVisitor,
SwitchIntEdgeEffects, fmt, graphviz, lattice, visit_results,
Analysis, Backward, Direction, Engine, Forward, GenKill, JoinSemiLattice, MaybeReachable,
Results, ResultsCursor, ResultsVisitable, ResultsVisitor, SwitchIntEdgeEffects, fmt, graphviz,
lattice, visit_results,
};
use self::move_paths::MoveData;

9
compiler/rustc_mir_dataflow/src/value_analysis.rs
View File

@ -51,7 +51,7 @@
use crate::fmt::DebugWithContext;
use crate::lattice::{HasBottom, HasTop};
use crate::{Analysis, AnalysisDomain, JoinSemiLattice, SwitchIntEdgeEffects};
use crate::{Analysis, JoinSemiLattice, SwitchIntEdgeEffects};
pub trait ValueAnalysis<'tcx> {
/// For each place of interest, the analysis tracks a value of the given type.
@ -334,7 +334,7 @@ fn wrap(self) -> ValueAnalysisWrapper<Self>
pub struct ValueAnalysisWrapper<T>(pub T);
impl<'tcx, T: ValueAnalysis<'tcx>> AnalysisDomain<'tcx> for ValueAnalysisWrapper<T> {
impl<'tcx, T: ValueAnalysis<'tcx>> Analysis<'tcx> for ValueAnalysisWrapper<T> {
type Domain = State<T::Value>;
const NAME: &'static str = T::NAME;
@ -351,12 +351,7 @@ fn initialize_start_block(&self, body: &Body<'tcx>, state: &mut Self::Domain) {
state.flood(PlaceRef { local: arg, projection: &[] }, self.0.map());
}
}
}
impl<'tcx, T> Analysis<'tcx> for ValueAnalysisWrapper<T>
where
T: ValueAnalysis<'tcx>,
{
fn apply_statement_effect(
&mut self,
state: &mut Self::Domain,

2
compiler/rustc_mir_transform/src/elaborate_drops.rs
View File

@ -133,7 +133,7 @@ fn seek_before(&mut self, loc: Location) {
}
fn maybe_live_dead(&self, path: MovePathIndex) -> (bool, bool) {
(self.inits.contains(path), self.uninits.contains(path))
(self.inits.get().contains(path), self.uninits.get().contains(path))
}
}

2
compiler/rustc_mir_transform/src/ref_prop.rs
View File

@ -179,7 +179,7 @@ fn compute_replacement<'tcx>(
} else {
// This is a proper dereference. We can only allow it if `target` is live.
maybe_dead.seek_after_primary_effect(loc);
let maybe_dead = maybe_dead.contains(target.local);
let maybe_dead = maybe_dead.get().contains(target.local);
!maybe_dead
}
};

4
src/tools/clippy/clippy_utils/src/mir/possible_borrower.rs
View File

@ -213,7 +213,7 @@ pub fn bounded_borrowers(
self.bitset.0.clear();
let maybe_live = &mut self.maybe_live;
if let Some(bitset) = self.map.get(&borrowed) {
for b in bitset.iter().filter(move |b| maybe_live.contains(*b)) {
for b in bitset.iter().filter(move |b| maybe_live.get().contains(*b)) {
self.bitset.0.insert(b);
}
} else {
@ -238,6 +238,6 @@ pub fn bounded_borrowers(
pub fn local_is_alive_at(&mut self, local: mir::Local, at: mir::Location) -> bool {
self.maybe_live.seek_after_primary_effect(at);
self.maybe_live.contains(local)
self.maybe_live.get().contains(local)
}
}