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Removed `BitDenotation: DataflowOperator` relationship.

Alpha-renamed `fn initial_value` to `fn bottom_value`.
This commit is contained in:
Felix S. Klock II 2016-05-20 14:14:18 +02:00
parent a7e3204ac8
commit 581195090a
2 changed files with 21 additions and 23 deletions
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41
src/librustc_borrowck/borrowck/mir/dataflow/mod.rs
View File

@ -35,7 +35,7 @@ pub trait Dataflow {
}
impl<'a, 'tcx: 'a, BD> Dataflow for MirBorrowckCtxtPreDataflow<'a, 'tcx, BD>
where BD: BitDenotation, BD::Bit: Debug, BD::Ctxt: HasMoveData<'tcx>
where BD: BitDenotation + DataflowOperator, BD::Bit: Debug, BD::Ctxt: HasMoveData<'tcx>
{
fn dataflow(&mut self) {
self.flow_state.build_sets();
@ -53,7 +53,7 @@ struct PropagationContext<'b, 'a: 'b, 'tcx: 'a, O>
}
impl<'a, 'tcx: 'a, BD> DataflowAnalysis<'a, 'tcx, BD>
where BD: BitDenotation, BD::Ctxt: HasMoveData<'tcx>
where BD: BitDenotation + DataflowOperator, BD::Ctxt: HasMoveData<'tcx>
{
fn propagate(&mut self) {
let mut temp = vec![0; self.flow_state.sets.words_per_block];
@ -100,10 +100,10 @@ impl<'a, 'tcx: 'a, BD> DataflowAnalysis<'a, 'tcx, BD>
}
impl<'b, 'a: 'b, 'tcx: 'a, BD> PropagationContext<'b, 'a, 'tcx, BD>
where BD: BitDenotation, BD::Ctxt: HasMoveData<'tcx>
where BD: BitDenotation + DataflowOperator, BD::Ctxt: HasMoveData<'tcx>
{
fn reset(&mut self, bits: &mut [usize]) {
let e = if BD::initial_value() {usize::MAX} else {0};
let e = if BD::bottom_value() {usize::MAX} else {0};
for b in bits {
*b = e;
}
@ -317,17 +317,17 @@ impl<O: BitDenotation> DataflowState<O> {
}
pub trait BitwiseOperator {
/// Joins two predecessor bits together, typically either `|` or `&`
/// Applies some bit-operation pointwise to each of the bits in the two inputs.
fn join(&self, pred1: usize, pred2: usize) -> usize;
}
/// Parameterization for the precise form of data flow that is used.
pub trait DataflowOperator : BitwiseOperator {
pub trait DataflowOperator: BitwiseOperator {
/// Specifies the initial value for each bit in the `on_entry` set
fn initial_value() -> bool;
fn bottom_value() -> bool;
}
pub trait BitDenotation: DataflowOperator {
pub trait BitDenotation {
/// Specifies what is represented by each bit in the dataflow bitvector.
type Bit;
@ -425,7 +425,7 @@ pub trait BitDenotation: DataflowOperator {
}
impl<'a, 'tcx: 'a, D> DataflowAnalysis<'a, 'tcx, D>
where D: BitDenotation, D::Ctxt: HasMoveData<'tcx>
where D: BitDenotation + DataflowOperator, D::Ctxt: HasMoveData<'tcx>
{
pub fn new(_tcx: TyCtxt<'a, 'tcx, 'tcx>,
mir: &'a Mir<'tcx>,
@ -437,7 +437,7 @@ impl<'a, 'tcx: 'a, D> DataflowAnalysis<'a, 'tcx, D>
let num_blocks = mir.basic_blocks.len();
let num_words = num_blocks * words_per_block;
let entry = if D::initial_value() { usize::MAX } else {0};
let entry = if D::bottom_value() { usize::MAX } else {0};
let zeroes = Bits::new(0, num_words);
let on_entry = Bits::new(entry, num_words);
@ -460,7 +460,7 @@ impl<'a, 'tcx: 'a, D> DataflowAnalysis<'a, 'tcx, D>
}
impl<'a, 'tcx: 'a, D> DataflowAnalysis<'a, 'tcx, D>
where D: BitDenotation, D::Ctxt: HasMoveData<'tcx>
where D: BitDenotation + DataflowOperator, D::Ctxt: HasMoveData<'tcx>
{
/// Propagates the bits of `in_out` into all the successors of `bb`,
/// using bitwise operator denoted by `self.operator`.
@ -851,7 +851,6 @@ impl<'a, 'tcx> BitDenotation for MaybeInitializedLvals<'a, 'tcx> {
fn interpret<'c>(&self, ctxt: &'c Self::Ctxt, idx: usize) -> &'c Self::Bit {
&ctxt.2.move_paths[MovePathIndex::new(idx)]
}
fn start_block_effect(&self, ctxt: &Self::Ctxt, sets: &mut BlockSets)
{
super::drop_flag_effects_for_function_entry(
@ -1072,12 +1071,10 @@ impl<'a, 'tcx> BitwiseOperator for DefinitelyInitializedLvals<'a, 'tcx> {
}
}
// FIXME: `DataflowOperator::initial_value` should be named
// `bottom_value`. The way that dataflow fixed point iteration works,
// you want to start at bottom and work your way to a fixed point.
// This needs to include the detail that the control-flow merges will
// apply the `join` operator above to current state (which starts at
// that bottom value).
// The way that dataflow fixed point iteration works, you want to
// start at bottom and work your way to a fixed point. Control-flow
// merges will apply the `join` operator to each block entry's current
// state (which starts at that bottom value).
//
// This means, for propagation across the graph, that you either want
// to start at all-zeroes and then use Union as your merge when
@ -1086,28 +1083,28 @@ impl<'a, 'tcx> BitwiseOperator for DefinitelyInitializedLvals<'a, 'tcx> {
impl<'a, 'tcx> DataflowOperator for MovingOutStatements<'a, 'tcx> {
#[inline]
fn initial_value() -> bool {
fn bottom_value() -> bool {
false // bottom = no loans in scope by default
}
}
impl<'a, 'tcx> DataflowOperator for MaybeInitializedLvals<'a, 'tcx> {
#[inline]
fn initial_value() -> bool {
fn bottom_value() -> bool {
false // bottom = uninitialized
}
}
impl<'a, 'tcx> DataflowOperator for MaybeUninitializedLvals<'a, 'tcx> {
#[inline]
fn initial_value() -> bool {
fn bottom_value() -> bool {
false // bottom = initialized (start_block_effect counters this at outset)
}
}
impl<'a, 'tcx> DataflowOperator for DefinitelyInitializedLvals<'a, 'tcx> {
#[inline]
fn initial_value() -> bool {
fn bottom_value() -> bool {
true // bottom = initialized
}
}

3
src/librustc_borrowck/borrowck/mir/mod.rs
View File

@ -29,6 +29,7 @@ mod gather_moves;
// mod graphviz;
use self::dataflow::{BitDenotation};
use self::dataflow::{DataflowOperator};
use self::dataflow::{Dataflow, DataflowAnalysis, DataflowResults};
use self::dataflow::{HasMoveData};
use self::dataflow::{MaybeInitializedLvals, MaybeUninitializedLvals};
@ -119,7 +120,7 @@ fn do_dataflow<'a, 'tcx, BD>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
attributes: &[ast::Attribute],
ctxt: BD::Ctxt,
bd: BD) -> (BD::Ctxt, DataflowResults<BD>)
where BD: BitDenotation, BD::Bit: Debug, BD::Ctxt: HasMoveData<'tcx>
where BD: BitDenotation + DataflowOperator, BD::Bit: Debug, BD::Ctxt: HasMoveData<'tcx>
{
use syntax::attr::AttrMetaMethods;