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Rollup merge of #114354 - Zalathar:external-counters, r=jackh726

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coverage: Store BCB counter info externally, not directly in the BCB graph

When deciding how to instrument the underlying MIR for coverage, the `InstrumentCoverage` pass builds a simplified “Basic Counter Block” graph, and then allocates coverage counters/expressions to various nodes/edges in the BCB graph as necessary. Those counters/expressions are then injected into the function's MIR.

The awkward thing here is that the code for doing this needs `&mut` access to the graph, in order to associate coverage info with individual nodes, even though it isn't making any structural changes to the graph itself. That makes it harder to understand and modify the instrumentation code.

In addition, the graph alone can't hold all the information that is needed. There ends up being an extra vector of “intermediate expressions” that needs to be passed around separately anyway.

---

This PR simplifies things by instead storing all of that temporary coverage information in a number of side-tables inside `CoverageCounters`.

This makes it easier to see all of the information produced by the make-counters step, and how it is used by the inject-into-mir step.

---

Looking at the combined changes is possible, but I recommend reviewing the commits individually, because the big changes are mostly independent of each other (despite being conceptually related).
This commit is contained in:
Guillaume Gomez 2023-08-13 21:00:46 +02:00 committed by GitHub
commit 2442c9b724
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5 changed files with 223 additions and 257 deletions
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232
compiler/rustc_mir_transform/src/coverage/counters.rs
View File

@ -8,25 +8,50 @@ use debug::{DebugCounters, NESTED_INDENT};
use graph::{BasicCoverageBlock, BcbBranch, CoverageGraph, TraverseCoverageGraphWithLoops};
use spans::CoverageSpan;
use rustc_data_structures::fx::FxHashMap;
use rustc_data_structures::graph::WithNumNodes;
use rustc_index::bit_set::BitSet;
use rustc_index::IndexVec;
use rustc_middle::mir::coverage::*;
/// Manages the counter and expression indexes/IDs to generate `CoverageKind` components for MIR
/// `Coverage` statements.
/// Generates and stores coverage counter and coverage expression information
/// associated with nodes/edges in the BCB graph.
pub(super) struct CoverageCounters {
function_source_hash: u64,
next_counter_id: CounterId,
next_expression_id: ExpressionId,
/// Coverage counters/expressions that are associated with individual BCBs.
bcb_counters: IndexVec<BasicCoverageBlock, Option<CoverageKind>>,
/// Coverage counters/expressions that are associated with the control-flow
/// edge between two BCBs.
bcb_edge_counters: FxHashMap<(BasicCoverageBlock, BasicCoverageBlock), CoverageKind>,
/// Tracks which BCBs have a counter associated with some incoming edge.
/// Only used by debug assertions, to verify that BCBs with incoming edge
/// counters do not have their own physical counters (expressions are allowed).
bcb_has_incoming_edge_counters: BitSet<BasicCoverageBlock>,
/// Expression nodes that are not directly associated with any particular
/// BCB/edge, but are needed as operands to more complex expressions.
/// These are always `CoverageKind::Expression`.
pub(super) intermediate_expressions: Vec<CoverageKind>,
pub debug_counters: DebugCounters,
}
impl CoverageCounters {
pub fn new(function_source_hash: u64) -> Self {
pub(super) fn new(function_source_hash: u64, basic_coverage_blocks: &CoverageGraph) -> Self {
let num_bcbs = basic_coverage_blocks.num_nodes();
Self {
function_source_hash,
next_counter_id: CounterId::START,
next_expression_id: ExpressionId::START,
bcb_counters: IndexVec::from_elem_n(None, num_bcbs),
bcb_edge_counters: FxHashMap::default(),
bcb_has_incoming_edge_counters: BitSet::new_empty(num_bcbs),
intermediate_expressions: Vec::new(),
debug_counters: DebugCounters::new(),
}
}
@ -38,15 +63,14 @@ impl CoverageCounters {
}
/// Makes `CoverageKind` `Counter`s and `Expressions` for the `BasicCoverageBlock`s directly or
/// indirectly associated with `CoverageSpans`, and returns additional `Expression`s
/// indirectly associated with `CoverageSpans`, and accumulates additional `Expression`s
/// representing intermediate values.
pub fn make_bcb_counters(
&mut self,
basic_coverage_blocks: &mut CoverageGraph,
basic_coverage_blocks: &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)
) -> Result<(), Error> {
MakeBcbCounters::new(self, basic_coverage_blocks).make_bcb_counters(coverage_spans)
}
fn make_counter<F>(&mut self, debug_block_label_fn: F) -> CoverageKind
@ -106,21 +130,95 @@ impl CoverageCounters {
self.next_expression_id = next.next_id();
next
}
fn set_bcb_counter(
&mut self,
bcb: BasicCoverageBlock,
counter_kind: CoverageKind,
) -> Result<Operand, Error> {
debug_assert!(
// If the BCB has an edge counter (to be injected into a new `BasicBlock`), it can also
// have an expression (to be injected into an existing `BasicBlock` represented by this
// `BasicCoverageBlock`).
counter_kind.is_expression() || !self.bcb_has_incoming_edge_counters.contains(bcb),
"attempt to add a `Counter` to a BCB target with existing incoming edge counters"
);
let operand = counter_kind.as_operand();
if let Some(replaced) = self.bcb_counters[bcb].replace(counter_kind) {
Error::from_string(format!(
"attempt to set a BasicCoverageBlock coverage counter more than once; \
{bcb:?} already had counter {replaced:?}",
))
} else {
Ok(operand)
}
}
fn set_bcb_edge_counter(
&mut self,
from_bcb: BasicCoverageBlock,
to_bcb: BasicCoverageBlock,
counter_kind: CoverageKind,
) -> Result<Operand, Error> {
if level_enabled!(tracing::Level::DEBUG) {
// If the BCB has an edge counter (to be injected into a new `BasicBlock`), it can also
// have an expression (to be injected into an existing `BasicBlock` represented by this
// `BasicCoverageBlock`).
if self.bcb_counter(to_bcb).is_some_and(|c| !c.is_expression()) {
return Error::from_string(format!(
"attempt to add an incoming edge counter from {from_bcb:?} when the target BCB already \
has a `Counter`"
));
}
}
self.bcb_has_incoming_edge_counters.insert(to_bcb);
let operand = counter_kind.as_operand();
if let Some(replaced) = self.bcb_edge_counters.insert((from_bcb, to_bcb), counter_kind) {
Error::from_string(format!(
"attempt to set an edge counter more than once; from_bcb: \
{from_bcb:?} already had counter {replaced:?}",
))
} else {
Ok(operand)
}
}
pub(super) fn bcb_counter(&self, bcb: BasicCoverageBlock) -> Option<&CoverageKind> {
self.bcb_counters[bcb].as_ref()
}
pub(super) fn take_bcb_counter(&mut self, bcb: BasicCoverageBlock) -> Option<CoverageKind> {
self.bcb_counters[bcb].take()
}
pub(super) fn drain_bcb_counters(
&mut self,
) -> impl Iterator<Item = (BasicCoverageBlock, CoverageKind)> + '_ {
self.bcb_counters
.iter_enumerated_mut()
.filter_map(|(bcb, counter)| Some((bcb, counter.take()?)))
}
pub(super) fn drain_bcb_edge_counters(
&mut self,
) -> impl Iterator<Item = ((BasicCoverageBlock, BasicCoverageBlock), CoverageKind)> + '_ {
self.bcb_edge_counters.drain()
}
}
/// Traverse the `CoverageGraph` and add either a `Counter` or `Expression` to every BCB, to be
/// injected with `CoverageSpan`s. `Expressions` have no runtime overhead, so if a viable expression
/// (adding or subtracting two other counters or expressions) can compute the same result as an
/// embedded counter, an `Expression` should be used.
struct BcbCounters<'a> {
struct MakeBcbCounters<'a> {
coverage_counters: &'a mut CoverageCounters,
basic_coverage_blocks: &'a mut CoverageGraph,
basic_coverage_blocks: &'a CoverageGraph,
}
impl<'a> BcbCounters<'a> {
impl<'a> MakeBcbCounters<'a> {
fn new(
coverage_counters: &'a mut CoverageCounters,
basic_coverage_blocks: &'a mut CoverageGraph,
basic_coverage_blocks: &'a CoverageGraph,
) -> Self {
Self { coverage_counters, basic_coverage_blocks }
}
@ -135,13 +233,9 @@ impl<'a> BcbCounters<'a> {
/// Returns any non-code-span expressions created to represent intermediate values (such as to
/// add two counters so the result can be subtracted from another counter), or an Error with
/// message for subsequent debugging.
fn make_bcb_counters(
&mut self,
coverage_spans: &[CoverageSpan],
) -> Result<Vec<CoverageKind>, Error> {
fn make_bcb_counters(&mut self, coverage_spans: &[CoverageSpan]) -> Result<(), 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 {
@ -162,16 +256,10 @@ impl<'a> BcbCounters<'a> {
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)?;
let branching_counter_operand = self.get_or_make_counter_operand(bcb)?;
if self.bcb_needs_branch_counters(bcb) {
self.make_branch_counters(
&mut traversal,
bcb,
branching_counter_operand,
&mut collect_intermediate_expressions,
)?;
self.make_branch_counters(&mut traversal, bcb, branching_counter_operand)?;
}
} else {
debug!(
@ -183,7 +271,7 @@ impl<'a> BcbCounters<'a> {
}
if traversal.is_complete() {
Ok(collect_intermediate_expressions)
Ok(())
} else {
Error::from_string(format!(
"`TraverseCoverageGraphWithLoops` missed some `BasicCoverageBlock`s: {:?}",
@ -197,7 +285,6 @@ impl<'a> BcbCounters<'a> {
traversal: &mut TraverseCoverageGraphWithLoops,
branching_bcb: BasicCoverageBlock,
branching_counter_operand: Operand,
collect_intermediate_expressions: &mut Vec<CoverageKind>,
) -> Result<(), Error> {
let branches = self.bcb_branches(branching_bcb);
debug!(
@ -205,9 +292,7 @@ impl<'a> BcbCounters<'a> {
branching_bcb,
branches
.iter()
.map(|branch| {
format!("{:?}: {:?}", branch, branch.counter(&self.basic_coverage_blocks))
})
.map(|branch| { format!("{:?}: {:?}", branch, self.branch_counter(branch)) })
.collect::<Vec<_>>()
.join("\n "),
);
@ -233,17 +318,10 @@ impl<'a> BcbCounters<'a> {
counter",
branch, branching_bcb
);
self.get_or_make_counter_operand(
branch.target_bcb,
collect_intermediate_expressions,
)?
self.get_or_make_counter_operand(branch.target_bcb)?
} 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,
)?
self.get_or_make_edge_counter_operand(branching_bcb, branch.target_bcb)?
};
if let Some(sumup_counter_operand) =
some_sumup_counter_operand.replace(branch_counter_operand)
@ -259,7 +337,7 @@ impl<'a> BcbCounters<'a> {
self.format_counter(&intermediate_expression)
);
let intermediate_expression_operand = intermediate_expression.as_operand();
collect_intermediate_expressions.push(intermediate_expression);
self.coverage_counters.intermediate_expressions.push(intermediate_expression);
some_sumup_counter_operand.replace(intermediate_expression_operand);
}
}
@ -284,29 +362,24 @@ impl<'a> BcbCounters<'a> {
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)?;
self.coverage_counters.set_bcb_counter(bcb, expression)?;
} else {
self.basic_coverage_blocks[bcb].set_edge_counter_from(branching_bcb, expression)?;
self.coverage_counters.set_bcb_edge_counter(branching_bcb, bcb, expression)?;
}
Ok(())
}
fn get_or_make_counter_operand(
&mut self,
bcb: BasicCoverageBlock,
collect_intermediate_expressions: &mut Vec<CoverageKind>,
) -> Result<Operand, Error> {
self.recursive_get_or_make_counter_operand(bcb, collect_intermediate_expressions, 1)
fn get_or_make_counter_operand(&mut self, bcb: BasicCoverageBlock) -> Result<Operand, Error> {
self.recursive_get_or_make_counter_operand(bcb, 1)
}
fn recursive_get_or_make_counter_operand(
&mut self,
bcb: BasicCoverageBlock,
collect_intermediate_expressions: &mut Vec<CoverageKind>,
debug_indent_level: usize,
) -> Result<Operand, Error> {
// If the BCB already has a counter, return it.
if let Some(counter_kind) = self.basic_coverage_blocks[bcb].counter() {
if let Some(counter_kind) = &self.coverage_counters.bcb_counters[bcb] {
debug!(
"{}{:?} already has a counter: {}",
NESTED_INDENT.repeat(debug_indent_level),
@ -339,7 +412,7 @@ impl<'a> BcbCounters<'a> {
self.format_counter(&counter_kind),
);
}
return self.basic_coverage_blocks[bcb].set_counter(counter_kind);
return self.coverage_counters.set_bcb_counter(bcb, counter_kind);
}
// A BCB with multiple incoming edges can compute its count by `Expression`, summing up the
@ -355,7 +428,6 @@ impl<'a> BcbCounters<'a> {
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;
@ -363,7 +435,6 @@ impl<'a> BcbCounters<'a> {
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) =
@ -381,7 +452,7 @@ impl<'a> BcbCounters<'a> {
self.format_counter(&intermediate_expression)
);
let intermediate_expression_operand = intermediate_expression.as_operand();
collect_intermediate_expressions.push(intermediate_expression);
self.coverage_counters.intermediate_expressions.push(intermediate_expression);
some_sumup_edge_counter_operand.replace(intermediate_expression_operand);
}
}
@ -397,43 +468,34 @@ impl<'a> BcbCounters<'a> {
bcb,
self.format_counter(&counter_kind)
);
self.basic_coverage_blocks[bcb].set_counter(counter_kind)
self.coverage_counters.set_bcb_counter(bcb, counter_kind)
}
fn get_or_make_edge_counter_operand(
&mut self,
from_bcb: BasicCoverageBlock,
to_bcb: BasicCoverageBlock,
collect_intermediate_expressions: &mut Vec<CoverageKind>,
) -> Result<Operand, Error> {
self.recursive_get_or_make_edge_counter_operand(
from_bcb,
to_bcb,
collect_intermediate_expressions,
1,
)
self.recursive_get_or_make_edge_counter_operand(from_bcb, to_bcb, 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<Operand, Error> {
// If the source BCB has only one successor (assumed to be the given target), an edge
// counter is unnecessary. Just get or make a counter for the source BCB.
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,
);
return self.recursive_get_or_make_counter_operand(from_bcb, debug_indent_level + 1);
}
// If the edge already has a counter, return it.
if let Some(counter_kind) = self.basic_coverage_blocks[to_bcb].edge_counter_from(from_bcb) {
if let Some(counter_kind) =
self.coverage_counters.bcb_edge_counters.get(&(from_bcb, to_bcb))
{
debug!(
"{}Edge {:?}->{:?} already has a counter: {}",
NESTED_INDENT.repeat(debug_indent_level),
@ -454,7 +516,7 @@ impl<'a> BcbCounters<'a> {
to_bcb,
self.format_counter(&counter_kind)
);
self.basic_coverage_blocks[to_bcb].set_edge_counter_from(from_bcb, counter_kind)
self.coverage_counters.set_bcb_edge_counter(from_bcb, to_bcb, counter_kind)
}
/// Select a branch for the expression, either the recommended `reloop_branch`, or if none was
@ -464,8 +526,7 @@ impl<'a> BcbCounters<'a> {
traversal: &TraverseCoverageGraphWithLoops,
branches: &[BcbBranch],
) -> BcbBranch {
let branch_needs_a_counter =
|branch: &BcbBranch| branch.counter(&self.basic_coverage_blocks).is_none();
let branch_needs_a_counter = |branch: &BcbBranch| self.branch_has_no_counter(branch);
let some_reloop_branch = self.find_some_reloop_branch(traversal, &branches);
if let Some(reloop_branch_without_counter) =
@ -478,10 +539,8 @@ impl<'a> BcbCounters<'a> {
);
reloop_branch_without_counter
} else {
let &branch_without_counter = branches
.iter()
.find(|&&branch| branch.counter(&self.basic_coverage_blocks).is_none())
.expect(
let &branch_without_counter =
branches.iter().find(|&branch| self.branch_has_no_counter(branch)).expect(
"needs_branch_counters was `true` so there should be at least one \
branch",
);
@ -508,8 +567,7 @@ impl<'a> BcbCounters<'a> {
traversal: &TraverseCoverageGraphWithLoops,
branches: &[BcbBranch],
) -> Option<BcbBranch> {
let branch_needs_a_counter =
|branch: &BcbBranch| branch.counter(&self.basic_coverage_blocks).is_none();
let branch_needs_a_counter = |branch: &BcbBranch| self.branch_has_no_counter(branch);
let mut some_reloop_branch: Option<BcbBranch> = None;
for context in traversal.context_stack.iter().rev() {
@ -520,7 +578,7 @@ impl<'a> BcbCounters<'a> {
self.bcb_dominates(branch.target_bcb, backedge_from_bcb)
}) {
if let Some(reloop_branch) = some_reloop_branch {
if reloop_branch.counter(&self.basic_coverage_blocks).is_none() {
if self.branch_has_no_counter(&reloop_branch) {
// we already found a candidate reloop_branch that still
// needs a counter
continue;
@ -586,12 +644,24 @@ impl<'a> BcbCounters<'a> {
}
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 branch_needs_a_counter = |branch: &BcbBranch| self.branch_has_no_counter(branch);
let branches = self.bcb_branches(bcb);
branches.len() > 1 && branches.iter().any(branch_needs_a_counter)
}
fn branch_has_no_counter(&self, branch: &BcbBranch) -> bool {
self.branch_counter(branch).is_none()
}
fn branch_counter(&self, branch: &BcbBranch) -> Option<&CoverageKind> {
let to_bcb = branch.target_bcb;
if let Some(from_bcb) = branch.edge_from_bcb {
self.coverage_counters.bcb_edge_counters.get(&(from_bcb, to_bcb))
} else {
self.coverage_counters.bcb_counters[to_bcb].as_ref()
}
}
/// Returns true if the BasicCoverageBlock has zero or one incoming edge. (If zero, it should be
/// the entry point for the function.)
#[inline]

15
compiler/rustc_mir_transform/src/coverage/debug.rs
View File

@ -108,6 +108,7 @@
//! recursively, generating labels with nested operations, enclosed in parentheses
//! (for example: `bcb2 + (bcb0 - bcb1)`).
use super::counters::CoverageCounters;
use super::graph::{BasicCoverageBlock, BasicCoverageBlockData, CoverageGraph};
use super::spans::CoverageSpan;
@ -659,18 +660,21 @@ pub(super) fn dump_coverage_graphviz<'tcx>(
mir_body: &mir::Body<'tcx>,
pass_name: &str,
basic_coverage_blocks: &CoverageGraph,
debug_counters: &DebugCounters,
coverage_counters: &CoverageCounters,
graphviz_data: &GraphvizData,
intermediate_expressions: &[CoverageKind],
debug_used_expressions: &UsedExpressions,
) {
let debug_counters = &coverage_counters.debug_counters;
let mir_source = mir_body.source;
let def_id = mir_source.def_id();
let node_content = |bcb| {
bcb_to_string_sections(
tcx,
mir_body,
debug_counters,
coverage_counters,
bcb,
&basic_coverage_blocks[bcb],
graphviz_data.get_bcb_coverage_spans_with_counters(bcb),
graphviz_data.get_bcb_dependency_counters(bcb),
@ -736,12 +740,15 @@ pub(super) fn dump_coverage_graphviz<'tcx>(
fn bcb_to_string_sections<'tcx>(
tcx: TyCtxt<'tcx>,
mir_body: &mir::Body<'tcx>,
debug_counters: &DebugCounters,
coverage_counters: &CoverageCounters,
bcb: BasicCoverageBlock,
bcb_data: &BasicCoverageBlockData,
some_coverage_spans_with_counters: Option<&[(CoverageSpan, CoverageKind)]>,
some_dependency_counters: Option<&[CoverageKind]>,
some_intermediate_expressions: Option<&[CoverageKind]>,
) -> Vec<String> {
let debug_counters = &coverage_counters.debug_counters;
let len = bcb_data.basic_blocks.len();
let mut sections = Vec::new();
if let Some(collect_intermediate_expressions) = some_intermediate_expressions {
@ -777,7 +784,7 @@ fn bcb_to_string_sections<'tcx>(
.join(" \n"),
));
}
if let Some(counter_kind) = &bcb_data.counter_kind {
if let Some(counter_kind) = coverage_counters.bcb_counter(bcb) {
sections.push(format!("{counter_kind:?}"));
}
let non_term_blocks = bcb_data.basic_blocks[0..len - 1]

105
compiler/rustc_mir_transform/src/coverage/graph.rs
View File

@ -1,12 +1,8 @@
use super::Error;
use itertools::Itertools;
use rustc_data_structures::fx::FxHashMap;
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_middle::mir::coverage::*;
use rustc_middle::mir::{self, BasicBlock, BasicBlockData, Terminator, TerminatorKind};
use std::cmp::Ordering;
@ -15,10 +11,7 @@ use std::ops::{Index, IndexMut};
const ID_SEPARATOR: &str = ",";
/// A coverage-specific simplification of the MIR control flow graph (CFG). The `CoverageGraph`s
/// nodes are `BasicCoverageBlock`s, which encompass one or more MIR `BasicBlock`s, plus a
/// `CoverageKind` counter (to be added by `CoverageCounters::make_bcb_counters`), and an optional
/// set of additional counters--if needed--to count incoming edges, if there are more than one.
/// (These "edge counters" are eventually converted into new MIR `BasicBlock`s.)
/// nodes are `BasicCoverageBlock`s, which encompass one or more MIR `BasicBlock`s.
#[derive(Debug)]
pub(super) struct CoverageGraph {
bcbs: IndexVec<BasicCoverageBlock, BasicCoverageBlockData>,
@ -195,13 +188,6 @@ impl CoverageGraph {
self.bcbs.iter_enumerated()
}
#[inline(always)]
pub fn iter_enumerated_mut(
&mut self,
) -> impl Iterator<Item = (BasicCoverageBlock, &mut BasicCoverageBlockData)> {
self.bcbs.iter_enumerated_mut()
}
#[inline(always)]
pub fn bcb_from_bb(&self, bb: BasicBlock) -> Option<BasicCoverageBlock> {
if bb.index() < self.bb_to_bcb.len() { self.bb_to_bcb[bb] } else { None }
@ -320,14 +306,12 @@ rustc_index::newtype_index! {
#[derive(Debug, Clone)]
pub(super) struct BasicCoverageBlockData {
pub basic_blocks: Vec<BasicBlock>,
pub counter_kind: Option<CoverageKind>,
edge_from_bcbs: Option<FxHashMap<BasicCoverageBlock, CoverageKind>>,
}
impl BasicCoverageBlockData {
pub fn from(basic_blocks: Vec<BasicBlock>) -> Self {
assert!(basic_blocks.len() > 0);
Self { basic_blocks, counter_kind: None, edge_from_bcbs: None }
Self { basic_blocks }
}
#[inline(always)]
@ -345,80 +329,6 @@ impl BasicCoverageBlockData {
&mir_body[self.last_bb()].terminator()
}
pub fn set_counter(&mut self, counter_kind: CoverageKind) -> Result<Operand, Error> {
debug_assert!(
// If the BCB has an edge counter (to be injected into a new `BasicBlock`), it can also
// have an expression (to be injected into an existing `BasicBlock` represented by this
// `BasicCoverageBlock`).
self.edge_from_bcbs.is_none() || counter_kind.is_expression(),
"attempt to add a `Counter` to a BCB target with existing incoming edge counters"
);
let operand = counter_kind.as_operand();
if let Some(replaced) = self.counter_kind.replace(counter_kind) {
Error::from_string(format!(
"attempt to set a BasicCoverageBlock coverage counter more than once; \
{self:?} already had counter {replaced:?}",
))
} else {
Ok(operand)
}
}
#[inline(always)]
pub fn counter(&self) -> Option<&CoverageKind> {
self.counter_kind.as_ref()
}
#[inline(always)]
pub fn take_counter(&mut self) -> Option<CoverageKind> {
self.counter_kind.take()
}
pub fn set_edge_counter_from(
&mut self,
from_bcb: BasicCoverageBlock,
counter_kind: CoverageKind,
) -> Result<Operand, Error> {
if level_enabled!(tracing::Level::DEBUG) {
// If the BCB has an edge counter (to be injected into a new `BasicBlock`), it can also
// have an expression (to be injected into an existing `BasicBlock` represented by this
// `BasicCoverageBlock`).
if self.counter_kind.as_ref().is_some_and(|c| !c.is_expression()) {
return Error::from_string(format!(
"attempt to add an incoming edge counter from {from_bcb:?} when the target BCB already \
has a `Counter`"
));
}
}
let operand = counter_kind.as_operand();
if let Some(replaced) =
self.edge_from_bcbs.get_or_insert_default().insert(from_bcb, counter_kind)
{
Error::from_string(format!(
"attempt to set an edge counter more than once; from_bcb: \
{from_bcb:?} already had counter {replaced:?}",
))
} else {
Ok(operand)
}
}
#[inline]
pub fn edge_counter_from(&self, from_bcb: BasicCoverageBlock) -> Option<&CoverageKind> {
if let Some(edge_from_bcbs) = &self.edge_from_bcbs {
edge_from_bcbs.get(&from_bcb)
} else {
None
}
}
#[inline]
pub fn take_edge_counters(
&mut self,
) -> Option<impl Iterator<Item = (BasicCoverageBlock, CoverageKind)>> {
self.edge_from_bcbs.take().map(|m| m.into_iter())
}
pub fn id(&self) -> String {
format!("@{}", self.basic_blocks.iter().map(|bb| bb.index().to_string()).join(ID_SEPARATOR))
}
@ -448,17 +358,6 @@ impl BcbBranch {
Self { edge_from_bcb, target_bcb: to_bcb }
}
pub fn counter<'a>(
&self,
basic_coverage_blocks: &'a CoverageGraph,
) -> Option<&'a CoverageKind> {
if let Some(from_bcb) = self.edge_from_bcb {
basic_coverage_blocks[self.target_bcb].edge_counter_from(from_bcb)
} else {
basic_coverage_blocks[self.target_bcb].counter()
}
}
pub fn is_only_path_to_target(&self) -> bool {
self.edge_from_bcb.is_none()
}

118
compiler/rustc_mir_transform/src/coverage/mod.rs
View File

@ -137,6 +137,8 @@ impl<'a, 'tcx> Instrumentor<'a, 'tcx> {
let function_source_hash = hash_mir_source(tcx, hir_body);
let basic_coverage_blocks = CoverageGraph::from_mir(mir_body);
let coverage_counters = CoverageCounters::new(function_source_hash, &basic_coverage_blocks);
Self {
pass_name,
tcx,
@ -145,7 +147,7 @@ impl<'a, 'tcx> Instrumentor<'a, 'tcx> {
fn_sig_span,
body_span,
basic_coverage_blocks,
coverage_counters: CoverageCounters::new(function_source_hash),
coverage_counters,
}
}
@ -199,52 +201,47 @@ impl<'a, 'tcx> Instrumentor<'a, 'tcx> {
// `BasicCoverageBlock`s not already associated with a `CoverageSpan`.
//
// Intermediate expressions (used to compute other `Expression` values), which have no
// direct associate to any `BasicCoverageBlock`, are returned in the method `Result`.
let intermediate_expressions_or_error = self
// direct association with any `BasicCoverageBlock`, are accumulated inside `coverage_counters`.
let result = self
.coverage_counters
.make_bcb_counters(&mut self.basic_coverage_blocks, &coverage_spans);
let (result, intermediate_expressions) = match intermediate_expressions_or_error {
Ok(intermediate_expressions) => {
// If debugging, add any intermediate expressions (which are not associated with any
// BCB) to the `debug_used_expressions` map.
if debug_used_expressions.is_enabled() {
for intermediate_expression in &intermediate_expressions {
debug_used_expressions.add_expression_operands(intermediate_expression);
}
if let Ok(()) = result {
// If debugging, add any intermediate expressions (which are not associated with any
// BCB) to the `debug_used_expressions` map.
if debug_used_expressions.is_enabled() {
for intermediate_expression in &self.coverage_counters.intermediate_expressions {
debug_used_expressions.add_expression_operands(intermediate_expression);
}
////////////////////////////////////////////////////
// Remove the counter or edge counter from of each `CoverageSpan`s associated
// `BasicCoverageBlock`, and inject a `Coverage` statement into the MIR.
//
// `Coverage` statements injected from `CoverageSpan`s will include the code regions
// (source code start and end positions) to be counted by the associated counter.
//
// These `CoverageSpan`-associated counters are removed from their associated
// `BasicCoverageBlock`s so that the only remaining counters in the `CoverageGraph`
// are indirect counters (to be injected next, without associated code regions).
self.inject_coverage_span_counters(
coverage_spans,
&mut graphviz_data,
&mut debug_used_expressions,
);
////////////////////////////////////////////////////
// For any remaining `BasicCoverageBlock` counters (that were not associated with
// any `CoverageSpan`), inject `Coverage` statements (_without_ code region `Span`s)
// to ensure `BasicCoverageBlock` counters that other `Expression`s may depend on
// are in fact counted, even though they don't directly contribute to counting
// their own independent code region's coverage.
self.inject_indirect_counters(&mut graphviz_data, &mut debug_used_expressions);
// Intermediate expressions will be injected as the final step, after generating
// debug output, if any.
////////////////////////////////////////////////////
(Ok(()), intermediate_expressions)
}
Err(e) => (Err(e), Vec::new()),
////////////////////////////////////////////////////
// Remove the counter or edge counter from of each `CoverageSpan`s associated
// `BasicCoverageBlock`, and inject a `Coverage` statement into the MIR.
//
// `Coverage` statements injected from `CoverageSpan`s will include the code regions
// (source code start and end positions) to be counted by the associated counter.
//
// These `CoverageSpan`-associated counters are removed from their associated
// `BasicCoverageBlock`s so that the only remaining counters in the `CoverageGraph`
// are indirect counters (to be injected next, without associated code regions).
self.inject_coverage_span_counters(
coverage_spans,
&mut graphviz_data,
&mut debug_used_expressions,
);
////////////////////////////////////////////////////
// For any remaining `BasicCoverageBlock` counters (that were not associated with
// any `CoverageSpan`), inject `Coverage` statements (_without_ code region `Span`s)
// to ensure `BasicCoverageBlock` counters that other `Expression`s may depend on
// are in fact counted, even though they don't directly contribute to counting
// their own independent code region's coverage.
self.inject_indirect_counters(&mut graphviz_data, &mut debug_used_expressions);
// Intermediate expressions will be injected as the final step, after generating
// debug output, if any.
////////////////////////////////////////////////////
};
if graphviz_data.is_enabled() {
@ -255,9 +252,9 @@ impl<'a, 'tcx> Instrumentor<'a, 'tcx> {
self.mir_body,
self.pass_name,
&self.basic_coverage_blocks,
&self.coverage_counters.debug_counters,
&self.coverage_counters,
&graphviz_data,
&intermediate_expressions,
&self.coverage_counters.intermediate_expressions,
&debug_used_expressions,
);
}
@ -273,7 +270,7 @@ impl<'a, 'tcx> Instrumentor<'a, 'tcx> {
////////////////////////////////////////////////////
// Finally, inject the intermediate expressions collected along the way.
for intermediate_expression in intermediate_expressions {
for intermediate_expression in self.coverage_counters.intermediate_expressions.drain(..) {
inject_intermediate_expression(self.mir_body, intermediate_expression);
}
}
@ -303,7 +300,7 @@ impl<'a, 'tcx> Instrumentor<'a, 'tcx> {
let span = covspan.span;
let counter_kind = if let Some(&counter_operand) = bcb_counters[bcb].as_ref() {
self.coverage_counters.make_identity_counter(counter_operand)
} else if let Some(counter_kind) = self.bcb_data_mut(bcb).take_counter() {
} else if let Some(counter_kind) = self.coverage_counters.take_bcb_counter(bcb) {
bcb_counters[bcb] = Some(counter_kind.as_operand());
debug_used_expressions.add_expression_operands(&counter_kind);
counter_kind
@ -343,19 +340,17 @@ impl<'a, 'tcx> Instrumentor<'a, 'tcx> {
debug_used_expressions: &mut debug::UsedExpressions,
) {
let mut bcb_counters_without_direct_coverage_spans = Vec::new();
for (target_bcb, target_bcb_data) in self.basic_coverage_blocks.iter_enumerated_mut() {
if let Some(counter_kind) = target_bcb_data.take_counter() {
bcb_counters_without_direct_coverage_spans.push((None, target_bcb, counter_kind));
}
if let Some(edge_counters) = target_bcb_data.take_edge_counters() {
for (from_bcb, counter_kind) in edge_counters {
bcb_counters_without_direct_coverage_spans.push((
Some(from_bcb),
target_bcb,
counter_kind,
));
}
}
for (target_bcb, counter_kind) in self.coverage_counters.drain_bcb_counters() {
bcb_counters_without_direct_coverage_spans.push((None, target_bcb, counter_kind));
}
for ((from_bcb, target_bcb), counter_kind) in
self.coverage_counters.drain_bcb_edge_counters()
{
bcb_counters_without_direct_coverage_spans.push((
Some(from_bcb),
target_bcb,
counter_kind,
));
}
// If debug is enabled, validate that every BCB or edge counter not directly associated
@ -430,11 +425,6 @@ impl<'a, 'tcx> Instrumentor<'a, 'tcx> {
&self.basic_coverage_blocks[bcb]
}
#[inline]
fn bcb_data_mut(&mut self, bcb: BasicCoverageBlock) -> &mut BasicCoverageBlockData {
&mut self.basic_coverage_blocks[bcb]
}
#[inline]
fn format_counter(&self, counter_kind: &CoverageKind) -> String {
self.coverage_counters.debug_counters.format_counter(counter_kind)

10
compiler/rustc_mir_transform/src/coverage/tests.rs
View File

@ -675,16 +675,16 @@ fn test_make_bcb_counters() {
));
}
}
let mut coverage_counters = counters::CoverageCounters::new(0);
let intermediate_expressions = coverage_counters
let mut coverage_counters = counters::CoverageCounters::new(0, &basic_coverage_blocks);
let () = coverage_counters
.make_bcb_counters(&mut basic_coverage_blocks, &coverage_spans)
.expect("should be Ok");
assert_eq!(intermediate_expressions.len(), 0);
assert_eq!(coverage_counters.intermediate_expressions.len(), 0);
let_bcb!(1);
assert_eq!(
0, // bcb1 has a `Counter` with id = 0
match basic_coverage_blocks[bcb1].counter().expect("should have a counter") {
match coverage_counters.bcb_counter(bcb1).expect("should have a counter") {
CoverageKind::Counter { id, .. } => id,
_ => panic!("expected a Counter"),
}
@ -694,7 +694,7 @@ fn test_make_bcb_counters() {
let_bcb!(2);
assert_eq!(
1, // bcb2 has a `Counter` with id = 1
match basic_coverage_blocks[bcb2].counter().expect("should have a counter") {
match coverage_counters.bcb_counter(bcb2).expect("should have a counter") {
CoverageKind::Counter { id, .. } => id,
_ => panic!("expected a Counter"),
}