Skip to content
This repository was archived by the owner on May 28, 2025. It is now read-only.

Commit 6c8b492

Browse files
author
zhuyunxing
committed
coverage. Split mcdc builder to a sub module of coverageinfo
1 parent e198c51 commit 6c8b492

File tree

2 files changed

+279
-269
lines changed

2 files changed

+279
-269
lines changed

‎compiler/rustc_mir_build/src/build/coverageinfo.rs‎

Lines changed: 4 additions & 269 deletions
Original file line numberDiff line numberDiff line change
@@ -1,20 +1,16 @@
1+
mod mcdc;
12
use std::assert_matches::assert_matches;
23
use std::collections::hash_map::Entry;
3-
use std::collections::VecDeque;
44

55
use rustc_data_structures::fx::FxHashMap;
6-
use rustc_middle::mir::coverage::{
7-
BlockMarkerId, BranchSpan, ConditionId, ConditionInfo, CoverageKind, MCDCBranchSpan,
8-
MCDCDecisionSpan,
9-
};
6+
use rustc_middle::mir::coverage::{BlockMarkerId, BranchSpan, CoverageKind};
107
use rustc_middle::mir::{self, BasicBlock, SourceInfo, UnOp};
11-
use rustc_middle::thir::{ExprId, ExprKind, LogicalOp, Thir};
8+
use rustc_middle::thir::{ExprId, ExprKind, Thir};
129
use rustc_middle::ty::TyCtxt;
1310
use rustc_span::def_id::LocalDefId;
14-
use rustc_span::Span;
1511

12+
use crate::build::coverageinfo::mcdc::MCDCInfoBuilder;
1613
use crate::build::{Builder, CFG};
17-
use crate::errors::MCDCExceedsConditionNumLimit;
1814

1915
pub(crate) struct BranchInfoBuilder {
2016
/// Maps condition expressions to their enclosing `!`, for better instrumentation.
@@ -159,241 +155,6 @@ impl BranchInfoBuilder {
159155
}
160156
}
161157

162-
/// The MCDC bitmap scales exponentially (2^n) based on the number of conditions seen,
163-
/// So llvm sets a maximum value prevents the bitmap footprint from growing too large without the user's knowledge.
164-
/// This limit may be relaxed if the [upstream change](https://github.com/llvm/llvm-project/pull/82448) is merged.
165-
const MAX_CONDITIONS_NUM_IN_DECISION: usize = 6;
166-
167-
#[derive(Default)]
168-
struct MCDCDecisionCtx {
169-
/// To construct condition evaluation tree.
170-
decision_stack: VecDeque<ConditionInfo>,
171-
processing_decision: Option<MCDCDecisionSpan>,
172-
}
173-
174-
struct MCDCState {
175-
decision_ctx_stack: Vec<MCDCDecisionCtx>,
176-
}
177-
178-
impl MCDCState {
179-
fn new() -> Self {
180-
Self { decision_ctx_stack: vec![MCDCDecisionCtx::default()] }
181-
}
182-
183-
/// Decision depth is given as a u16 to reduce the size of the `CoverageKind`,
184-
/// as it is very unlikely that the depth ever reaches 2^16.
185-
#[inline]
186-
fn decision_depth(&self) -> u16 {
187-
match u16::try_from(self.decision_ctx_stack.len())
188-
.expect(
189-
"decision depth did not fit in u16, this is likely to be an instrumentation error",
190-
)
191-
.checked_sub(1)
192-
{
193-
Some(d) => d,
194-
None => bug!("Unexpected empty decision stack"),
195-
}
196-
}
197-
198-
// At first we assign ConditionIds for each sub expression.
199-
// If the sub expression is composite, re-assign its ConditionId to its LHS and generate a new ConditionId for its RHS.
200-
//
201-
// Example: "x = (A && B) || (C && D) || (D && F)"
202-
//
203-
// Visit Depth1:
204-
// (A && B) || (C && D) || (D && F)
205-
// ^-------LHS--------^ ^-RHS--^
206-
// ID=1 ID=2
207-
//
208-
// Visit LHS-Depth2:
209-
// (A && B) || (C && D)
210-
// ^-LHS--^ ^-RHS--^
211-
// ID=1 ID=3
212-
//
213-
// Visit LHS-Depth3:
214-
// (A && B)
215-
// LHS RHS
216-
// ID=1 ID=4
217-
//
218-
// Visit RHS-Depth3:
219-
// (C && D)
220-
// LHS RHS
221-
// ID=3 ID=5
222-
//
223-
// Visit RHS-Depth2: (D && F)
224-
// LHS RHS
225-
// ID=2 ID=6
226-
//
227-
// Visit Depth1:
228-
// (A && B) || (C && D) || (D && F)
229-
// ID=1 ID=4 ID=3 ID=5 ID=2 ID=6
230-
//
231-
// A node ID of '0' always means MC/DC isn't being tracked.
232-
//
233-
// If a "next" node ID is '0', it means it's the end of the test vector.
234-
//
235-
// As the compiler tracks expression in pre-order, we can ensure that condition info of parents are always properly assigned when their children are visited.
236-
// - If the op is AND, the "false_next" of LHS and RHS should be the parent's "false_next". While "true_next" of the LHS is the RHS, the "true next" of RHS is the parent's "true_next".
237-
// - If the op is OR, the "true_next" of LHS and RHS should be the parent's "true_next". While "false_next" of the LHS is the RHS, the "false next" of RHS is the parent's "false_next".
238-
fn record_conditions(&mut self, op: LogicalOp, span: Span) {
239-
let decision_depth = self.decision_depth();
240-
let Some(decision_ctx) = self.decision_ctx_stack.last_mut() else {
241-
bug!("Unexpected empty decision_ctx_stack")
242-
};
243-
let decision = match decision_ctx.processing_decision.as_mut() {
244-
Some(decision) => {
245-
decision.span = decision.span.to(span);
246-
decision
247-
}
248-
None => decision_ctx.processing_decision.insert(MCDCDecisionSpan {
249-
span,
250-
conditions_num: 0,
251-
end_markers: vec![],
252-
decision_depth,
253-
}),
254-
};
255-
256-
let parent_condition = decision_ctx.decision_stack.pop_back().unwrap_or_default();
257-
let lhs_id = if parent_condition.condition_id == ConditionId::NONE {
258-
decision.conditions_num += 1;
259-
ConditionId::from(decision.conditions_num)
260-
} else {
261-
parent_condition.condition_id
262-
};
263-
264-
decision.conditions_num += 1;
265-
let rhs_condition_id = ConditionId::from(decision.conditions_num);
266-
267-
let (lhs, rhs) = match op {
268-
LogicalOp::And => {
269-
let lhs = ConditionInfo {
270-
condition_id: lhs_id,
271-
true_next_id: rhs_condition_id,
272-
false_next_id: parent_condition.false_next_id,
273-
};
274-
let rhs = ConditionInfo {
275-
condition_id: rhs_condition_id,
276-
true_next_id: parent_condition.true_next_id,
277-
false_next_id: parent_condition.false_next_id,
278-
};
279-
(lhs, rhs)
280-
}
281-
LogicalOp::Or => {
282-
let lhs = ConditionInfo {
283-
condition_id: lhs_id,
284-
true_next_id: parent_condition.true_next_id,
285-
false_next_id: rhs_condition_id,
286-
};
287-
let rhs = ConditionInfo {
288-
condition_id: rhs_condition_id,
289-
true_next_id: parent_condition.true_next_id,
290-
false_next_id: parent_condition.false_next_id,
291-
};
292-
(lhs, rhs)
293-
}
294-
};
295-
// We visit expressions tree in pre-order, so place the left-hand side on the top.
296-
decision_ctx.decision_stack.push_back(rhs);
297-
decision_ctx.decision_stack.push_back(lhs);
298-
}
299-
300-
fn take_condition(
301-
&mut self,
302-
true_marker: BlockMarkerId,
303-
false_marker: BlockMarkerId,
304-
) -> (Option<ConditionInfo>, Option<MCDCDecisionSpan>) {
305-
let Some(decision_ctx) = self.decision_ctx_stack.last_mut() else {
306-
bug!("Unexpected empty decision_ctx_stack")
307-
};
308-
let Some(condition_info) = decision_ctx.decision_stack.pop_back() else {
309-
return (None, None);
310-
};
311-
let Some(decision) = decision_ctx.processing_decision.as_mut() else {
312-
bug!("Processing decision should have been created before any conditions are taken");
313-
};
314-
if condition_info.true_next_id == ConditionId::NONE {
315-
decision.end_markers.push(true_marker);
316-
}
317-
if condition_info.false_next_id == ConditionId::NONE {
318-
decision.end_markers.push(false_marker);
319-
}
320-
321-
if decision_ctx.decision_stack.is_empty() {
322-
(Some(condition_info), decision_ctx.processing_decision.take())
323-
} else {
324-
(Some(condition_info), None)
325-
}
326-
}
327-
}
328-
329-
struct MCDCInfoBuilder {
330-
branch_spans: Vec<MCDCBranchSpan>,
331-
decision_spans: Vec<MCDCDecisionSpan>,
332-
state: MCDCState,
333-
}
334-
335-
impl MCDCInfoBuilder {
336-
fn new() -> Self {
337-
Self { branch_spans: vec![], decision_spans: vec![], state: MCDCState::new() }
338-
}
339-
340-
fn visit_evaluated_condition(
341-
&mut self,
342-
tcx: TyCtxt<'_>,
343-
source_info: SourceInfo,
344-
true_block: BasicBlock,
345-
false_block: BasicBlock,
346-
mut inject_block_marker: impl FnMut(SourceInfo, BasicBlock) -> BlockMarkerId,
347-
) {
348-
let true_marker = inject_block_marker(source_info, true_block);
349-
let false_marker = inject_block_marker(source_info, false_block);
350-
351-
let decision_depth = self.state.decision_depth();
352-
let (mut condition_info, decision_result) =
353-
self.state.take_condition(true_marker, false_marker);
354-
// take_condition() returns Some for decision_result when the decision stack
355-
// is empty, i.e. when all the conditions of the decision were instrumented,
356-
// and the decision is "complete".
357-
if let Some(decision) = decision_result {
358-
match decision.conditions_num {
359-
0 => {
360-
unreachable!("Decision with no condition is not expected");
361-
}
362-
1..=MAX_CONDITIONS_NUM_IN_DECISION => {
363-
self.decision_spans.push(decision);
364-
}
365-
_ => {
366-
// Do not generate mcdc mappings and statements for decisions with too many conditions.
367-
let rebase_idx = self.branch_spans.len() - decision.conditions_num + 1;
368-
for branch in &mut self.branch_spans[rebase_idx..] {
369-
branch.condition_info = None;
370-
}
371-
372-
// ConditionInfo of this branch shall also be reset.
373-
condition_info = None;
374-
375-
tcx.dcx().emit_warn(MCDCExceedsConditionNumLimit {
376-
span: decision.span,
377-
conditions_num: decision.conditions_num,
378-
max_conditions_num: MAX_CONDITIONS_NUM_IN_DECISION,
379-
});
380-
}
381-
}
382-
}
383-
self.branch_spans.push(MCDCBranchSpan {
384-
span: source_info.span,
385-
condition_info,
386-
true_marker,
387-
false_marker,
388-
decision_depth,
389-
});
390-
}
391-
392-
fn into_done(self) -> (Vec<MCDCDecisionSpan>, Vec<MCDCBranchSpan>) {
393-
(self.decision_spans, self.branch_spans)
394-
}
395-
}
396-
397158
impl Builder<'_, '_> {
398159
/// If branch coverage is enabled, inject marker statements into `then_block`
399160
/// and `else_block`, and record their IDs in the table of branch spans.
@@ -434,30 +195,4 @@ impl Builder<'_, '_> {
434195

435196
branch_info.add_two_way_branch(&mut self.cfg, source_info, then_block, else_block);
436197
}
437-
438-
pub(crate) fn visit_coverage_branch_operation(&mut self, logical_op: LogicalOp, span: Span) {
439-
if let Some(branch_info) = self.coverage_branch_info.as_mut()
440-
&& let Some(mcdc_info) = branch_info.mcdc_info.as_mut()
441-
{
442-
mcdc_info.state.record_conditions(logical_op, span);
443-
}
444-
}
445-
446-
pub(crate) fn mcdc_increment_depth_if_enabled(&mut self) {
447-
if let Some(branch_info) = self.coverage_branch_info.as_mut()
448-
&& let Some(mcdc_info) = branch_info.mcdc_info.as_mut()
449-
{
450-
mcdc_info.state.decision_ctx_stack.push(MCDCDecisionCtx::default());
451-
};
452-
}
453-
454-
pub(crate) fn mcdc_decrement_depth_if_enabled(&mut self) {
455-
if let Some(branch_info) = self.coverage_branch_info.as_mut()
456-
&& let Some(mcdc_info) = branch_info.mcdc_info.as_mut()
457-
{
458-
if mcdc_info.state.decision_ctx_stack.pop().is_none() {
459-
bug!("Unexpected empty decision stack");
460-
}
461-
};
462-
}
463198
}

0 commit comments

Comments
 (0)