coverage: Move helper add_basic_coverage_block into a local closure

This also switches from `split_off(0)` to `std::mem::take` when emptying the
accumulated list of blocks, because `split_off(0)` handles capacity in a way
that is unintuitive when used in a loop.
This commit is contained in:
Zalathar 2024-01-02 12:48:35 +11:00
parent 229d0983b5
commit 867950f8c6

View File

@ -2,7 +2,7 @@
use rustc_data_structures::graph::dominators::{self, Dominators};
use rustc_data_structures::graph::{self, GraphSuccessors, WithNumNodes, WithStartNode};
use rustc_index::bit_set::BitSet;
use rustc_index::{IndexSlice, IndexVec};
use rustc_index::IndexVec;
use rustc_middle::mir::{self, BasicBlock, Terminator, TerminatorKind};
use std::cmp::Ordering;
@ -81,9 +81,23 @@ fn compute_basic_coverage_blocks(
IndexVec<BasicBlock, Option<BasicCoverageBlock>>,
) {
let num_basic_blocks = mir_body.basic_blocks.len();
let mut bcbs = IndexVec::with_capacity(num_basic_blocks);
let mut bcbs = IndexVec::<BasicCoverageBlock, _>::with_capacity(num_basic_blocks);
let mut bb_to_bcb = IndexVec::from_elem_n(None, num_basic_blocks);
let mut add_basic_coverage_block = |basic_blocks: &mut Vec<BasicBlock>| {
// Take the accumulated list of blocks, leaving the vector empty
// to be used by subsequent BCBs.
let basic_blocks = std::mem::take(basic_blocks);
let bcb = bcbs.next_index();
for &bb in basic_blocks.iter() {
bb_to_bcb[bb] = Some(bcb);
}
let bcb_data = BasicCoverageBlockData::from(basic_blocks);
debug!("adding bcb{}: {:?}", bcb.index(), bcb_data);
bcbs.push(bcb_data);
};
// Walk the MIR CFG using a Preorder traversal, which starts from `START_BLOCK` and follows
// each block terminator's `successors()`. Coverage spans must map to actual source code,
// so compiler generated blocks and paths can be ignored. To that end, the CFG traversal
@ -113,11 +127,7 @@ fn compute_basic_coverage_blocks(
predecessors = ?&mir_body.basic_blocks.predecessors()[bb],
"can't chain from {prev:?} to {bb:?}"
);
Self::add_basic_coverage_block(
&mut bcbs,
&mut bb_to_bcb,
basic_blocks.split_off(0),
);
add_basic_coverage_block(&mut basic_blocks);
}
basic_blocks.push(bb);
@ -125,26 +135,12 @@ fn compute_basic_coverage_blocks(
if !basic_blocks.is_empty() {
debug!("flushing accumulated blocks into one last BCB");
Self::add_basic_coverage_block(&mut bcbs, &mut bb_to_bcb, basic_blocks.split_off(0));
add_basic_coverage_block(&mut basic_blocks);
}
(bcbs, bb_to_bcb)
}
fn add_basic_coverage_block(
bcbs: &mut IndexVec<BasicCoverageBlock, BasicCoverageBlockData>,
bb_to_bcb: &mut IndexSlice<BasicBlock, Option<BasicCoverageBlock>>,
basic_blocks: Vec<BasicBlock>,
) {
let bcb = bcbs.next_index();
for &bb in basic_blocks.iter() {
bb_to_bcb[bb] = Some(bcb);
}
let bcb_data = BasicCoverageBlockData::from(basic_blocks);
debug!("adding bcb{}: {:?}", bcb.index(), bcb_data);
bcbs.push(bcb_data);
}
#[inline(always)]
pub fn iter_enumerated(
&self,