diff options
Diffstat (limited to 'compiler/rustc_mir_build/src')
| -rw-r--r-- | compiler/rustc_mir_build/src/build/coverageinfo.rs | 6 | ||||
| -rw-r--r-- | compiler/rustc_mir_build/src/build/coverageinfo/mcdc.rs | 117 |
2 files changed, 71 insertions, 52 deletions
diff --git a/compiler/rustc_mir_build/src/build/coverageinfo.rs b/compiler/rustc_mir_build/src/build/coverageinfo.rs index 204ee45bfa2..52a4a4b4b51 100644 --- a/compiler/rustc_mir_build/src/build/coverageinfo.rs +++ b/compiler/rustc_mir_build/src/build/coverageinfo.rs @@ -175,7 +175,7 @@ impl CoverageInfoBuilder { let branch_spans = branch_info.map(|branch_info| branch_info.branch_spans).unwrap_or_default(); - let (mcdc_decision_spans, mcdc_branch_spans) = + let (mcdc_spans, mcdc_degraded_branch_spans) = mcdc_info.map(MCDCInfoBuilder::into_done).unwrap_or_default(); // For simplicity, always return an info struct (without Option), even @@ -183,8 +183,8 @@ impl CoverageInfoBuilder { Box::new(CoverageInfoHi { num_block_markers, branch_spans, - mcdc_branch_spans, - mcdc_decision_spans, + mcdc_degraded_branch_spans, + mcdc_spans, }) } } diff --git a/compiler/rustc_mir_build/src/build/coverageinfo/mcdc.rs b/compiler/rustc_mir_build/src/build/coverageinfo/mcdc.rs index 6019a93e787..343d4000043 100644 --- a/compiler/rustc_mir_build/src/build/coverageinfo/mcdc.rs +++ b/compiler/rustc_mir_build/src/build/coverageinfo/mcdc.rs @@ -12,16 +12,16 @@ use rustc_span::Span; use crate::build::Builder; use crate::errors::MCDCExceedsConditionLimit; -/// The MCDC bitmap scales exponentially (2^n) based on the number of conditions seen, -/// So llvm sets a maximum value prevents the bitmap footprint from growing too large without the user's knowledge. -/// This limit may be relaxed if the [upstream change](https://github.com/llvm/llvm-project/pull/82448) is merged. -const MAX_CONDITIONS_IN_DECISION: usize = 6; +/// LLVM uses `i16` to represent condition id. Hence `i16::MAX` is the hard limit for number of +/// conditions in a decision. +const MAX_CONDITIONS_IN_DECISION: usize = i16::MAX as usize; #[derive(Default)] struct MCDCDecisionCtx { /// To construct condition evaluation tree. decision_stack: VecDeque<ConditionInfo>, processing_decision: Option<MCDCDecisionSpan>, + conditions: Vec<MCDCBranchSpan>, } struct MCDCState { @@ -106,22 +106,27 @@ impl MCDCState { }), }; - let parent_condition = decision_ctx.decision_stack.pop_back().unwrap_or_default(); - let lhs_id = if parent_condition.condition_id == ConditionId::NONE { + let parent_condition = decision_ctx.decision_stack.pop_back().unwrap_or_else(|| { + assert_eq!( + decision.num_conditions, 0, + "decision stack must be empty only for empty decision" + ); decision.num_conditions += 1; - ConditionId::from(decision.num_conditions) - } else { - parent_condition.condition_id - }; + ConditionInfo { + condition_id: ConditionId::START, + true_next_id: None, + false_next_id: None, + } + }); + let lhs_id = parent_condition.condition_id; - decision.num_conditions += 1; let rhs_condition_id = ConditionId::from(decision.num_conditions); - + decision.num_conditions += 1; let (lhs, rhs) = match op { LogicalOp::And => { let lhs = ConditionInfo { condition_id: lhs_id, - true_next_id: rhs_condition_id, + true_next_id: Some(rhs_condition_id), false_next_id: parent_condition.false_next_id, }; let rhs = ConditionInfo { @@ -135,7 +140,7 @@ impl MCDCState { let lhs = ConditionInfo { condition_id: lhs_id, true_next_id: parent_condition.true_next_id, - false_next_id: rhs_condition_id, + false_next_id: Some(rhs_condition_id), }; let rhs = ConditionInfo { condition_id: rhs_condition_id, @@ -150,44 +155,64 @@ impl MCDCState { decision_ctx.decision_stack.push_back(lhs); } - fn take_condition( + fn try_finish_decision( &mut self, + span: Span, true_marker: BlockMarkerId, false_marker: BlockMarkerId, - ) -> (Option<ConditionInfo>, Option<MCDCDecisionSpan>) { + degraded_branches: &mut Vec<MCDCBranchSpan>, + ) -> Option<(MCDCDecisionSpan, Vec<MCDCBranchSpan>)> { let Some(decision_ctx) = self.decision_ctx_stack.last_mut() else { bug!("Unexpected empty decision_ctx_stack") }; let Some(condition_info) = decision_ctx.decision_stack.pop_back() else { - return (None, None); + let branch = MCDCBranchSpan { + span, + condition_info: ConditionInfo { + condition_id: ConditionId::START, + true_next_id: None, + false_next_id: None, + }, + true_marker, + false_marker, + }; + degraded_branches.push(branch); + return None; }; let Some(decision) = decision_ctx.processing_decision.as_mut() else { bug!("Processing decision should have been created before any conditions are taken"); }; - if condition_info.true_next_id == ConditionId::NONE { + if condition_info.true_next_id.is_none() { decision.end_markers.push(true_marker); } - if condition_info.false_next_id == ConditionId::NONE { + if condition_info.false_next_id.is_none() { decision.end_markers.push(false_marker); } + decision_ctx.conditions.push(MCDCBranchSpan { + span, + condition_info, + true_marker, + false_marker, + }); if decision_ctx.decision_stack.is_empty() { - (Some(condition_info), decision_ctx.processing_decision.take()) + let conditions = std::mem::take(&mut decision_ctx.conditions); + decision_ctx.processing_decision.take().map(|decision| (decision, conditions)) } else { - (Some(condition_info), None) + None } } } pub(crate) struct MCDCInfoBuilder { - branch_spans: Vec<MCDCBranchSpan>, - decision_spans: Vec<MCDCDecisionSpan>, + degraded_spans: Vec<MCDCBranchSpan>, + mcdc_spans: Vec<(MCDCDecisionSpan, Vec<MCDCBranchSpan>)>, state: MCDCState, } impl MCDCInfoBuilder { pub(crate) fn new() -> Self { - Self { branch_spans: vec![], decision_spans: vec![], state: MCDCState::new() } + Self { degraded_spans: vec![], mcdc_spans: vec![], state: MCDCState::new() } } pub(crate) fn visit_evaluated_condition( @@ -201,50 +226,44 @@ impl MCDCInfoBuilder { let true_marker = inject_block_marker(source_info, true_block); let false_marker = inject_block_marker(source_info, false_block); - let decision_depth = self.state.decision_depth(); - let (mut condition_info, decision_result) = - self.state.take_condition(true_marker, false_marker); // take_condition() returns Some for decision_result when the decision stack // is empty, i.e. when all the conditions of the decision were instrumented, // and the decision is "complete". - if let Some(decision) = decision_result { - match decision.num_conditions { + if let Some((decision, conditions)) = self.state.try_finish_decision( + source_info.span, + true_marker, + false_marker, + &mut self.degraded_spans, + ) { + let num_conditions = conditions.len(); + assert_eq!( + num_conditions, decision.num_conditions, + "final number of conditions is not correct" + ); + match num_conditions { 0 => { unreachable!("Decision with no condition is not expected"); } 1..=MAX_CONDITIONS_IN_DECISION => { - self.decision_spans.push(decision); + self.mcdc_spans.push((decision, conditions)); } _ => { - // Do not generate mcdc mappings and statements for decisions with too many conditions. - // Therefore, first erase the condition info of the (N-1) previous branch spans. - let rebase_idx = self.branch_spans.len() - (decision.num_conditions - 1); - for branch in &mut self.branch_spans[rebase_idx..] { - branch.condition_info = None; - } - - // Then, erase this last branch span's info too, for a total of N. - condition_info = None; + self.degraded_spans.extend(conditions); tcx.dcx().emit_warn(MCDCExceedsConditionLimit { span: decision.span, - num_conditions: decision.num_conditions, + num_conditions, max_conditions: MAX_CONDITIONS_IN_DECISION, }); } } } - self.branch_spans.push(MCDCBranchSpan { - span: source_info.span, - condition_info, - true_marker, - false_marker, - decision_depth, - }); } - pub(crate) fn into_done(self) -> (Vec<MCDCDecisionSpan>, Vec<MCDCBranchSpan>) { - (self.decision_spans, self.branch_spans) + pub(crate) fn into_done( + self, + ) -> (Vec<(MCDCDecisionSpan, Vec<MCDCBranchSpan>)>, Vec<MCDCBranchSpan>) { + (self.mcdc_spans, self.degraded_spans) } } |