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Merge apply_effects_in_block and join_state_into_successors_of.
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They are always called in succession, so it's simpler if they are merged
into a single function.
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@nnethercote
nnethercote committed Nov 26, 2024
1 parent 481b5fa commit 0066acf
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Showing 2 changed files with 132 additions and 162 deletions.
285 changes: 130 additions & 155 deletions compiler/rustc_mir_dataflow/src/framework/direction.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,16 @@ pub trait Direction {

const IS_BACKWARD: bool = !Self::IS_FORWARD;

fn apply_effects_in_block<'mir, 'tcx, A>(
analysis: &mut A,
body: &mir::Body<'tcx>,
state: &mut A::Domain,
block: BasicBlock,
block_data: &'mir mir::BasicBlockData<'tcx>,
propagate: impl FnMut(BasicBlock, &A::Domain),
) where
A: Analysis<'tcx>;

/// Applies all effects between the given `EffectIndex`s.
///
/// `effects.start()` must precede or equal `effects.end()` in this direction.
Expand All @@ -24,15 +34,6 @@ pub trait Direction {
) where
A: Analysis<'tcx>;

fn apply_effects_in_block<'mir, 'tcx, A>(
analysis: &mut A,
state: &mut A::Domain,
block: BasicBlock,
block_data: &'mir mir::BasicBlockData<'tcx>,
) -> TerminatorEdges<'mir, 'tcx>
where
A: Analysis<'tcx>;

fn visit_results_in_block<'mir, 'tcx, A>(
state: &mut A::Domain,
block: BasicBlock,
Expand All @@ -41,16 +42,6 @@ pub trait Direction {
vis: &mut impl ResultsVisitor<'mir, 'tcx, A>,
) where
A: Analysis<'tcx>;

fn join_state_into_successors_of<'tcx, A>(
analysis: &mut A,
body: &mir::Body<'tcx>,
exit_state: &mut A::Domain,
block: BasicBlock,
edges: TerminatorEdges<'_, 'tcx>,
propagate: impl FnMut(BasicBlock, &A::Domain),
) where
A: Analysis<'tcx>;
}

/// Dataflow that runs from the exit of a block (terminator), to its entry (the first statement).
Expand All @@ -61,23 +52,84 @@ impl Direction for Backward {

fn apply_effects_in_block<'mir, 'tcx, A>(
analysis: &mut A,
body: &mir::Body<'tcx>,
state: &mut A::Domain,
block: BasicBlock,
block_data: &'mir mir::BasicBlockData<'tcx>,
) -> TerminatorEdges<'mir, 'tcx>
where
mut propagate: impl FnMut(BasicBlock, &A::Domain),
) where
A: Analysis<'tcx>,
{
let terminator = block_data.terminator();
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);
analysis.apply_terminator_effect(state, terminator, location);
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

let exit_state = state;
for pred in body.basic_blocks.predecessors()[block].iter().copied() {
match body[pred].terminator().kind {
// Apply terminator-specific edge effects.
//
// FIXME(ecstaticmorse): Avoid cloning the exit state unconditionally.
mir::TerminatorKind::Call { destination, target: Some(dest), .. }
if dest == block =>
{
let mut tmp = exit_state.clone();
analysis.apply_call_return_effect(
&mut tmp,
pred,
CallReturnPlaces::Call(destination),
);
propagate(pred, &tmp);
}

mir::TerminatorKind::InlineAsm { ref targets, ref operands, .. }
if targets.contains(&block) =>
{
let mut tmp = exit_state.clone();
analysis.apply_call_return_effect(
&mut tmp,
pred,
CallReturnPlaces::InlineAsm(operands),
);
propagate(pred, &tmp);
}

mir::TerminatorKind::Yield { resume, resume_arg, .. } if resume == block => {
let mut tmp = exit_state.clone();
analysis.apply_call_return_effect(
&mut tmp,
resume,
CallReturnPlaces::Yield(resume_arg),
);
propagate(pred, &tmp);
}

mir::TerminatorKind::SwitchInt { targets: _, ref discr } => {
let mut applier = BackwardSwitchIntEdgeEffectsApplier {
body,
pred,
exit_state,
block,
propagate: &mut propagate,
effects_applied: false,
};

analysis.apply_switch_int_edge_effects(pred, discr, &mut applier);

if !applier.effects_applied {
propagate(pred, exit_state)
}
}

_ => propagate(pred, exit_state),
}
}
}

fn apply_effects_in_range<'tcx, A>(
Expand Down Expand Up @@ -188,82 +240,13 @@ impl Direction for Backward {

vis.visit_block_start(state);
}

fn join_state_into_successors_of<'tcx, A>(
analysis: &mut A,
body: &mir::Body<'tcx>,
exit_state: &mut A::Domain,
bb: BasicBlock,
_edges: TerminatorEdges<'_, 'tcx>,
mut propagate: impl FnMut(BasicBlock, &A::Domain),
) where
A: Analysis<'tcx>,
{
for pred in body.basic_blocks.predecessors()[bb].iter().copied() {
match body[pred].terminator().kind {
// Apply terminator-specific edge effects.
//
// FIXME(ecstaticmorse): Avoid cloning the exit state unconditionally.
mir::TerminatorKind::Call { destination, target: Some(dest), .. } if dest == bb => {
let mut tmp = exit_state.clone();
analysis.apply_call_return_effect(
&mut tmp,
pred,
CallReturnPlaces::Call(destination),
);
propagate(pred, &tmp);
}

mir::TerminatorKind::InlineAsm { ref targets, ref operands, .. }
if targets.contains(&bb) =>
{
let mut tmp = exit_state.clone();
analysis.apply_call_return_effect(
&mut tmp,
pred,
CallReturnPlaces::InlineAsm(operands),
);
propagate(pred, &tmp);
}

mir::TerminatorKind::Yield { resume, resume_arg, .. } if resume == bb => {
let mut tmp = exit_state.clone();
analysis.apply_call_return_effect(
&mut tmp,
resume,
CallReturnPlaces::Yield(resume_arg),
);
propagate(pred, &tmp);
}

mir::TerminatorKind::SwitchInt { targets: _, ref discr } => {
let mut applier = BackwardSwitchIntEdgeEffectsApplier {
body,
pred,
exit_state,
bb,
propagate: &mut propagate,
effects_applied: false,
};

analysis.apply_switch_int_edge_effects(pred, discr, &mut applier);

if !applier.effects_applied {
propagate(pred, exit_state)
}
}

_ => propagate(pred, exit_state),
}
}
}
}

struct BackwardSwitchIntEdgeEffectsApplier<'mir, 'tcx, D, F> {
body: &'mir mir::Body<'tcx>,
pred: BasicBlock,
exit_state: &'mir mut D,
bb: BasicBlock,
block: BasicBlock,
propagate: &'mir mut F,
effects_applied: bool,
}
Expand All @@ -276,8 +259,8 @@ where
fn apply(&mut self, mut apply_edge_effect: impl FnMut(&mut D, SwitchIntTarget)) {
assert!(!self.effects_applied);

let values = &self.body.basic_blocks.switch_sources()[&(self.bb, self.pred)];
let targets = values.iter().map(|&value| SwitchIntTarget { value, target: self.bb });
let values = &self.body.basic_blocks.switch_sources()[&(self.block, self.pred)];
let targets = values.iter().map(|&value| SwitchIntTarget { value, target: self.block });

let mut tmp = None;
for target in targets {
Expand All @@ -298,11 +281,12 @@ impl Direction for Forward {

fn apply_effects_in_block<'mir, 'tcx, A>(
analysis: &mut A,
_body: &mir::Body<'tcx>,
state: &mut A::Domain,
block: BasicBlock,
block_data: &'mir mir::BasicBlockData<'tcx>,
) -> TerminatorEdges<'mir, 'tcx>
where
mut propagate: impl FnMut(BasicBlock, &A::Domain),
) where
A: Analysis<'tcx>,
{
for (statement_index, statement) in block_data.statements.iter().enumerate() {
Expand All @@ -313,7 +297,53 @@ impl Direction for Forward {
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)
let edges = analysis.apply_terminator_effect(state, terminator, location);

let exit_state = state;
match edges {
TerminatorEdges::None => {}
TerminatorEdges::Single(target) => propagate(target, exit_state),
TerminatorEdges::Double(target, unwind) => {
propagate(target, exit_state);
propagate(unwind, exit_state);
}
TerminatorEdges::AssignOnReturn { return_, cleanup, place } => {
// This must be done *first*, otherwise the unwind path will see the assignments.
if let Some(cleanup) = cleanup {
propagate(cleanup, exit_state);
}

if !return_.is_empty() {
analysis.apply_call_return_effect(exit_state, block, place);
for &target in return_ {
propagate(target, exit_state);
}
}
}
TerminatorEdges::SwitchInt { targets, discr } => {
let mut applier = ForwardSwitchIntEdgeEffectsApplier {
exit_state,
targets,
propagate,
effects_applied: false,
};

analysis.apply_switch_int_edge_effects(block, discr, &mut applier);

let ForwardSwitchIntEdgeEffectsApplier {
exit_state,
mut propagate,
effects_applied,
..
} = applier;

if !effects_applied {
for target in targets.all_targets() {
propagate(*target, exit_state);
}
}
}
}
}

fn apply_effects_in_range<'tcx, A>(
Expand Down Expand Up @@ -351,7 +381,8 @@ impl Direction for Forward {
let statement = &block_data.statements[from.statement_index];
analysis.apply_statement_effect(state, statement, location);

// If we only needed to apply the after effect of the statement at `idx`, we are done.
// If we only needed to apply the after effect of the statement at `idx`, we are
// done.
if from == to {
return;
}
Expand Down Expand Up @@ -419,62 +450,6 @@ impl Direction for Forward {

vis.visit_block_end(state);
}

fn join_state_into_successors_of<'tcx, A>(
analysis: &mut A,
_body: &mir::Body<'tcx>,
exit_state: &mut A::Domain,
bb: BasicBlock,
edges: TerminatorEdges<'_, 'tcx>,
mut propagate: impl FnMut(BasicBlock, &A::Domain),
) where
A: Analysis<'tcx>,
{
match edges {
TerminatorEdges::None => {}
TerminatorEdges::Single(target) => propagate(target, exit_state),
TerminatorEdges::Double(target, unwind) => {
propagate(target, exit_state);
propagate(unwind, exit_state);
}
TerminatorEdges::AssignOnReturn { return_, cleanup, place } => {
// This must be done *first*, otherwise the unwind path will see the assignments.
if let Some(cleanup) = cleanup {
propagate(cleanup, exit_state);
}

if !return_.is_empty() {
analysis.apply_call_return_effect(exit_state, bb, place);
for &target in return_ {
propagate(target, exit_state);
}
}
}
TerminatorEdges::SwitchInt { targets, discr } => {
let mut applier = ForwardSwitchIntEdgeEffectsApplier {
exit_state,
targets,
propagate,
effects_applied: false,
};

analysis.apply_switch_int_edge_effects(bb, discr, &mut applier);

let ForwardSwitchIntEdgeEffectsApplier {
exit_state,
mut propagate,
effects_applied,
..
} = applier;

if !effects_applied {
for target in targets.all_targets() {
propagate(*target, exit_state);
}
}
}
}
}
}

struct ForwardSwitchIntEdgeEffectsApplier<'mir, D, F> {
Expand Down
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