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use super::Error;
use super::debug;
use super::graph;
use super::spans;
use debug::{DebugCounters, NESTED_INDENT};
use graph::{BasicCoverageBlock, BcbBranch, CoverageGraph, TraverseCoverageGraphWithLoops};
use spans::CoverageSpan;
use rustc_data_structures::graph::WithNumNodes;
use rustc_index::bit_set::BitSet;
use rustc_middle::mir::coverage::*;
pub(super) struct CoverageCounters {
function_source_hash: u64,
next_counter_id: u32,
num_expressions: u32,
pub debug_counters: DebugCounters,
}
impl CoverageCounters {
pub fn new(function_source_hash: u64) -> Self {
Self {
function_source_hash,
next_counter_id: CounterValueReference::START.as_u32(),
num_expressions: 0,
debug_counters: DebugCounters::new(),
}
}
pub fn enable_debug(&mut self) {
self.debug_counters.enable();
}
pub fn make_bcb_counters(
&mut self,
basic_coverage_blocks: &mut CoverageGraph,
coverage_spans: &[CoverageSpan],
) -> Result<Vec<CoverageKind>, Error> {
let mut bcb_counters = BcbCounters::new(self, basic_coverage_blocks);
bcb_counters.make_bcb_counters(coverage_spans)
}
fn make_counter<F>(&mut self, debug_block_label_fn: F) -> CoverageKind
where
F: Fn() -> Option<String>,
{
let counter = CoverageKind::Counter {
function_source_hash: self.function_source_hash,
id: self.next_counter(),
};
if self.debug_counters.is_enabled() {
self.debug_counters.add_counter(&counter, (debug_block_label_fn)());
}
counter
}
fn make_expression<F>(
&mut self,
lhs: ExpressionOperandId,
op: Op,
rhs: ExpressionOperandId,
debug_block_label_fn: F,
) -> CoverageKind
where
F: Fn() -> Option<String>,
{
let id = self.next_expression();
let expression = CoverageKind::Expression { id, lhs, op, rhs };
if self.debug_counters.is_enabled() {
self.debug_counters.add_counter(&expression, (debug_block_label_fn)());
}
expression
}
pub fn make_identity_counter(&mut self, counter_operand: ExpressionOperandId) -> CoverageKind {
let some_debug_block_label = if self.debug_counters.is_enabled() {
self.debug_counters.some_block_label(counter_operand).cloned()
} else {
None
};
self.make_expression(counter_operand, Op::Add, ExpressionOperandId::ZERO, || {
some_debug_block_label.clone()
})
}
fn next_counter(&mut self) -> CounterValueReference {
assert!(self.next_counter_id < u32::MAX - self.num_expressions);
let next = self.next_counter_id;
self.next_counter_id += 1;
CounterValueReference::from(next)
}
fn next_expression(&mut self) -> InjectedExpressionId {
assert!(self.next_counter_id < u32::MAX - self.num_expressions);
let next = u32::MAX - self.num_expressions;
self.num_expressions += 1;
InjectedExpressionId::from(next)
}
}
struct BcbCounters<'a> {
coverage_counters: &'a mut CoverageCounters,
basic_coverage_blocks: &'a mut CoverageGraph,
}
impl<'a> BcbCounters<'a> {
fn new(
coverage_counters: &'a mut CoverageCounters,
basic_coverage_blocks: &'a mut CoverageGraph,
) -> Self {
Self { coverage_counters, basic_coverage_blocks }
}
fn make_bcb_counters(
&mut self,
coverage_spans: &[CoverageSpan],
) -> Result<Vec<CoverageKind>, Error> {
debug!("make_bcb_counters(): adding a counter or expression to each BasicCoverageBlock");
let num_bcbs = self.basic_coverage_blocks.num_nodes();
let mut collect_intermediate_expressions = Vec::with_capacity(num_bcbs);
let mut bcbs_with_coverage = BitSet::new_empty(num_bcbs);
for covspan in coverage_spans {
bcbs_with_coverage.insert(covspan.bcb);
}
let mut traversal = TraverseCoverageGraphWithLoops::new(&self.basic_coverage_blocks);
while let Some(bcb) = traversal.next(self.basic_coverage_blocks) {
if bcbs_with_coverage.contains(bcb) {
debug!("{:?} has at least one `CoverageSpan`. Get or make its counter", bcb);
let branching_counter_operand =
self.get_or_make_counter_operand(bcb, &mut collect_intermediate_expressions)?;
if self.bcb_needs_branch_counters(bcb) {
self.make_branch_counters(
&mut traversal,
bcb,
branching_counter_operand,
&mut collect_intermediate_expressions,
)?;
}
} else {
debug!(
"{:?} does not have any `CoverageSpan`s. A counter will only be added if \
and when a covered BCB has an expression dependency.",
bcb,
);
}
}
if traversal.is_complete() {
Ok(collect_intermediate_expressions)
} else {
Error::from_string(format!(
"`TraverseCoverageGraphWithLoops` missed some `BasicCoverageBlock`s: {:?}",
traversal.unvisited(),
))
}
}
fn make_branch_counters(
&mut self,
traversal: &mut TraverseCoverageGraphWithLoops,
branching_bcb: BasicCoverageBlock,
branching_counter_operand: ExpressionOperandId,
collect_intermediate_expressions: &mut Vec<CoverageKind>,
) -> Result<(), Error> {
let branches = self.bcb_branches(branching_bcb);
debug!(
"{:?} has some branch(es) without counters:\n {}",
branching_bcb,
branches
.iter()
.map(|branch| {
format!("{:?}: {:?}", branch, branch.counter(&self.basic_coverage_blocks))
})
.collect::<Vec<_>>()
.join("\n "),
);
let expression_branch = self.choose_preferred_expression_branch(traversal, &branches);
let mut some_sumup_counter_operand = None;
for branch in branches {
if branch != expression_branch {
let branch_counter_operand = if branch.is_only_path_to_target() {
debug!(
" {:?} has only one incoming edge (from {:?}), so adding a \
counter",
branch, branching_bcb
);
self.get_or_make_counter_operand(
branch.target_bcb,
collect_intermediate_expressions,
)?
} else {
debug!(" {:?} has multiple incoming edges, so adding an edge counter", branch);
self.get_or_make_edge_counter_operand(
branching_bcb,
branch.target_bcb,
collect_intermediate_expressions,
)?
};
if let Some(sumup_counter_operand) =
some_sumup_counter_operand.replace(branch_counter_operand)
{
let intermediate_expression = self.coverage_counters.make_expression(
branch_counter_operand,
Op::Add,
sumup_counter_operand,
|| None,
);
debug!(
" [new intermediate expression: {}]",
self.format_counter(&intermediate_expression)
);
let intermediate_expression_operand = intermediate_expression.as_operand_id();
collect_intermediate_expressions.push(intermediate_expression);
some_sumup_counter_operand.replace(intermediate_expression_operand);
}
}
}
let sumup_counter_operand =
some_sumup_counter_operand.expect("sumup_counter_operand should have a value");
debug!(
"Making an expression for the selected expression_branch: {:?} \
(expression_branch predecessors: {:?})",
expression_branch,
self.bcb_predecessors(expression_branch.target_bcb),
);
let expression = self.coverage_counters.make_expression(
branching_counter_operand,
Op::Subtract,
sumup_counter_operand,
|| Some(format!("{:?}", expression_branch)),
);
debug!("{:?} gets an expression: {}", expression_branch, self.format_counter(&expression));
let bcb = expression_branch.target_bcb;
if expression_branch.is_only_path_to_target() {
self.basic_coverage_blocks[bcb].set_counter(expression)?;
} else {
self.basic_coverage_blocks[bcb].set_edge_counter_from(branching_bcb, expression)?;
}
Ok(())
}
fn get_or_make_counter_operand(
&mut self,
bcb: BasicCoverageBlock,
collect_intermediate_expressions: &mut Vec<CoverageKind>,
) -> Result<ExpressionOperandId, Error> {
self.recursive_get_or_make_counter_operand(bcb, collect_intermediate_expressions, 1)
}
fn recursive_get_or_make_counter_operand(
&mut self,
bcb: BasicCoverageBlock,
collect_intermediate_expressions: &mut Vec<CoverageKind>,
debug_indent_level: usize,
) -> Result<ExpressionOperandId, Error> {
if let Some(counter_kind) = self.basic_coverage_blocks[bcb].counter() {
debug!(
"{}{:?} already has a counter: {}",
NESTED_INDENT.repeat(debug_indent_level),
bcb,
self.format_counter(counter_kind),
);
return Ok(counter_kind.as_operand_id());
}
let one_path_to_target = self.bcb_has_one_path_to_target(bcb);
if one_path_to_target || self.bcb_predecessors(bcb).contains(&bcb) {
let counter_kind = self.coverage_counters.make_counter(|| Some(format!("{:?}", bcb)));
if one_path_to_target {
debug!(
"{}{:?} gets a new counter: {}",
NESTED_INDENT.repeat(debug_indent_level),
bcb,
self.format_counter(&counter_kind),
);
} else {
debug!(
"{}{:?} has itself as its own predecessor. It can't be part of its own \
Expression sum, so it will get its own new counter: {}. (Note, the compiled \
code will generate an infinite loop.)",
NESTED_INDENT.repeat(debug_indent_level),
bcb,
self.format_counter(&counter_kind),
);
}
return self.basic_coverage_blocks[bcb].set_counter(counter_kind);
}
let mut predecessors = self.bcb_predecessors(bcb).to_owned().into_iter();
debug!(
"{}{:?} has multiple incoming edges and will get an expression that sums them up...",
NESTED_INDENT.repeat(debug_indent_level),
bcb,
);
let first_edge_counter_operand = self.recursive_get_or_make_edge_counter_operand(
predecessors.next().unwrap(),
bcb,
collect_intermediate_expressions,
debug_indent_level + 1,
)?;
let mut some_sumup_edge_counter_operand = None;
for predecessor in predecessors {
let edge_counter_operand = self.recursive_get_or_make_edge_counter_operand(
predecessor,
bcb,
collect_intermediate_expressions,
debug_indent_level + 1,
)?;
if let Some(sumup_edge_counter_operand) =
some_sumup_edge_counter_operand.replace(edge_counter_operand)
{
let intermediate_expression = self.coverage_counters.make_expression(
sumup_edge_counter_operand,
Op::Add,
edge_counter_operand,
|| None,
);
debug!(
"{}new intermediate expression: {}",
NESTED_INDENT.repeat(debug_indent_level),
self.format_counter(&intermediate_expression)
);
let intermediate_expression_operand = intermediate_expression.as_operand_id();
collect_intermediate_expressions.push(intermediate_expression);
some_sumup_edge_counter_operand.replace(intermediate_expression_operand);
}
}
let counter_kind = self.coverage_counters.make_expression(
first_edge_counter_operand,
Op::Add,
some_sumup_edge_counter_operand.unwrap(),
|| Some(format!("{:?}", bcb)),
);
debug!(
"{}{:?} gets a new counter (sum of predecessor counters): {}",
NESTED_INDENT.repeat(debug_indent_level),
bcb,
self.format_counter(&counter_kind)
);
self.basic_coverage_blocks[bcb].set_counter(counter_kind)
}
fn get_or_make_edge_counter_operand(
&mut self,
from_bcb: BasicCoverageBlock,
to_bcb: BasicCoverageBlock,
collect_intermediate_expressions: &mut Vec<CoverageKind>,
) -> Result<ExpressionOperandId, Error> {
self.recursive_get_or_make_edge_counter_operand(
from_bcb,
to_bcb,
collect_intermediate_expressions,
1,
)
}
fn recursive_get_or_make_edge_counter_operand(
&mut self,
from_bcb: BasicCoverageBlock,
to_bcb: BasicCoverageBlock,
collect_intermediate_expressions: &mut Vec<CoverageKind>,
debug_indent_level: usize,
) -> Result<ExpressionOperandId, Error> {
let successors = self.bcb_successors(from_bcb).iter();
if successors.len() == 1 {
return self.recursive_get_or_make_counter_operand(
from_bcb,
collect_intermediate_expressions,
debug_indent_level + 1,
);
}
if let Some(counter_kind) = self.basic_coverage_blocks[to_bcb].edge_counter_from(from_bcb) {
debug!(
"{}Edge {:?}->{:?} already has a counter: {}",
NESTED_INDENT.repeat(debug_indent_level),
from_bcb,
to_bcb,
self.format_counter(counter_kind)
);
return Ok(counter_kind.as_operand_id());
}
let counter_kind =
self.coverage_counters.make_counter(|| Some(format!("{:?}->{:?}", from_bcb, to_bcb)));
debug!(
"{}Edge {:?}->{:?} gets a new counter: {}",
NESTED_INDENT.repeat(debug_indent_level),
from_bcb,
to_bcb,
self.format_counter(&counter_kind)
);
self.basic_coverage_blocks[to_bcb].set_edge_counter_from(from_bcb, counter_kind)
}
fn choose_preferred_expression_branch(
&self,
traversal: &TraverseCoverageGraphWithLoops,
branches: &[BcbBranch],
) -> BcbBranch {
let branch_needs_a_counter =
|branch: &BcbBranch| branch.counter(&self.basic_coverage_blocks).is_none();
let some_reloop_branch = self.find_some_reloop_branch(traversal, &branches);
if let Some(reloop_branch_without_counter) =
some_reloop_branch.filter(branch_needs_a_counter)
{
debug!(
"Selecting reloop_branch={:?} that still needs a counter, to get the \
`Expression`",
reloop_branch_without_counter
);
reloop_branch_without_counter
} else {
let &branch_without_counter = branches
.iter()
.find(|&&branch| branch.counter(&self.basic_coverage_blocks).is_none())
.expect(
"needs_branch_counters was `true` so there should be at least one \
branch",
);
debug!(
"Selecting any branch={:?} that still needs a counter, to get the \
`Expression` because there was no `reloop_branch`, or it already had a \
counter",
branch_without_counter
);
branch_without_counter
}
}
fn find_some_reloop_branch(
&self,
traversal: &TraverseCoverageGraphWithLoops,
branches: &[BcbBranch],
) -> Option<BcbBranch> {
let branch_needs_a_counter =
|branch: &BcbBranch| branch.counter(&self.basic_coverage_blocks).is_none();
let mut some_reloop_branch: Option<BcbBranch> = None;
for context in traversal.context_stack.iter().rev() {
if let Some((backedge_from_bcbs, _)) = &context.loop_backedges {
let mut found_loop_exit = false;
for &branch in branches.iter() {
if backedge_from_bcbs.iter().any(|&backedge_from_bcb| {
self.bcb_is_dominated_by(backedge_from_bcb, branch.target_bcb)
}) {
if let Some(reloop_branch) = some_reloop_branch {
if reloop_branch.counter(&self.basic_coverage_blocks).is_none() {
continue;
}
}
some_reloop_branch = Some(branch);
} else {
found_loop_exit = true;
}
if found_loop_exit
&& some_reloop_branch.filter(branch_needs_a_counter).is_some()
{
break;
}
}
if !found_loop_exit {
debug!(
"No branches exit the loop, so any branch without an existing \
counter can have the `Expression`."
);
break;
}
if some_reloop_branch.is_some() {
debug!(
"Found a branch that exits the loop and a branch the loops back to \
the top of the loop (`reloop_branch`). The `reloop_branch` will \
get the `Expression`, as long as it still needs a counter."
);
break;
}
}
}
some_reloop_branch
}
#[inline]
fn bcb_predecessors(&self, bcb: BasicCoverageBlock) -> &[BasicCoverageBlock] {
&self.basic_coverage_blocks.predecessors[bcb]
}
#[inline]
fn bcb_successors(&self, bcb: BasicCoverageBlock) -> &[BasicCoverageBlock] {
&self.basic_coverage_blocks.successors[bcb]
}
#[inline]
fn bcb_branches(&self, from_bcb: BasicCoverageBlock) -> Vec<BcbBranch> {
self.bcb_successors(from_bcb)
.iter()
.map(|&to_bcb| BcbBranch::from_to(from_bcb, to_bcb, &self.basic_coverage_blocks))
.collect::<Vec<_>>()
}
fn bcb_needs_branch_counters(&self, bcb: BasicCoverageBlock) -> bool {
let branch_needs_a_counter =
|branch: &BcbBranch| branch.counter(&self.basic_coverage_blocks).is_none();
let branches = self.bcb_branches(bcb);
branches.len() > 1 && branches.iter().any(branch_needs_a_counter)
}
#[inline]
fn bcb_has_one_path_to_target(&self, bcb: BasicCoverageBlock) -> bool {
self.bcb_predecessors(bcb).len() <= 1
}
#[inline]
fn bcb_is_dominated_by(&self, node: BasicCoverageBlock, dom: BasicCoverageBlock) -> bool {
self.basic_coverage_blocks.is_dominated_by(node, dom)
}
#[inline]
fn format_counter(&self, counter_kind: &CoverageKind) -> String {
self.coverage_counters.debug_counters.format_counter(counter_kind)
}
}