+++ /dev/null
-use super::*;
-
-use rustc_middle::mir::coverage::*;
-use rustc_middle::mir::{self, Body, Coverage, CoverageInfo};
-use rustc_middle::ty::query::Providers;
-use rustc_middle::ty::{self, TyCtxt};
-use rustc_span::def_id::DefId;
-
-/// A `query` provider for retrieving coverage information injected into MIR.
-pub(crate) fn provide(providers: &mut Providers) {
- providers.coverageinfo = |tcx, def_id| coverageinfo(tcx, def_id);
- providers.covered_file_name = |tcx, def_id| covered_file_name(tcx, def_id);
- providers.covered_code_regions = |tcx, def_id| covered_code_regions(tcx, def_id);
-}
-
-/// The `num_counters` argument to `llvm.instrprof.increment` is the max counter_id + 1, or in
-/// other words, the number of counter value references injected into the MIR (plus 1 for the
-/// reserved `ZERO` counter, which uses counter ID `0` when included in an expression). Injected
-/// counters have a counter ID from `1..num_counters-1`.
-///
-/// `num_expressions` is the number of counter expressions added to the MIR body.
-///
-/// Both `num_counters` and `num_expressions` are used to initialize new vectors, during backend
-/// code generate, to lookup counters and expressions by simple u32 indexes.
-///
-/// MIR optimization may split and duplicate some BasicBlock sequences, or optimize out some code
-/// including injected counters. (It is OK if some counters are optimized out, but those counters
-/// are still included in the total `num_counters` or `num_expressions`.) Simply counting the
-/// calls may not work; but computing the number of counters or expressions by adding `1` to the
-/// highest ID (for a given instrumented function) is valid.
-///
-/// This visitor runs twice, first with `add_missing_operands` set to `false`, to find the maximum
-/// counter ID and maximum expression ID based on their enum variant `id` fields; then, as a
-/// safeguard, with `add_missing_operands` set to `true`, to find any other counter or expression
-/// IDs referenced by expression operands, if not already seen.
-///
-/// Ideally, each operand ID in a MIR `CoverageKind::Expression` will have a separate MIR `Coverage`
-/// statement for the `Counter` or `Expression` with the referenced ID. but since current or future
-/// MIR optimizations can theoretically optimize out segments of a MIR, it may not be possible to
-/// guarantee this, so the second pass ensures the `CoverageInfo` counts include all referenced IDs.
-struct CoverageVisitor {
- info: CoverageInfo,
- add_missing_operands: bool,
-}
-
-impl CoverageVisitor {
- /// Updates `num_counters` to the maximum encountered zero-based counter_id plus 1. Note the
- /// final computed number of counters should be the number of all `CoverageKind::Counter`
- /// statements in the MIR *plus one* for the implicit `ZERO` counter.
- #[inline(always)]
- fn update_num_counters(&mut self, counter_id: u32) {
- self.info.num_counters = std::cmp::max(self.info.num_counters, counter_id + 1);
- }
-
- /// Computes an expression index for each expression ID, and updates `num_expressions` to the
- /// maximum encountered index plus 1.
- #[inline(always)]
- fn update_num_expressions(&mut self, expression_id: u32) {
- let expression_index = u32::MAX - expression_id;
- self.info.num_expressions = std::cmp::max(self.info.num_expressions, expression_index + 1);
- }
-
- fn update_from_expression_operand(&mut self, operand_id: u32) {
- if operand_id >= self.info.num_counters {
- let operand_as_expression_index = u32::MAX - operand_id;
- if operand_as_expression_index >= self.info.num_expressions {
- // The operand ID is outside the known range of counter IDs and also outside the
- // known range of expression IDs. In either case, the result of a missing operand
- // (if and when used in an expression) will be zero, so from a computation
- // perspective, it doesn't matter whether it is interepretted as a counter or an
- // expression.
- //
- // However, the `num_counters` and `num_expressions` query results are used to
- // allocate arrays when generating the coverage map (during codegen), so choose
- // the type that grows either `num_counters` or `num_expressions` the least.
- if operand_id - self.info.num_counters
- < operand_as_expression_index - self.info.num_expressions
- {
- self.update_num_counters(operand_id)
- } else {
- self.update_num_expressions(operand_id)
- }
- }
- }
- }
-
- fn visit_body(&mut self, body: &Body<'_>) {
- for bb_data in body.basic_blocks().iter() {
- for statement in bb_data.statements.iter() {
- if let StatementKind::Coverage(box ref coverage) = statement.kind {
- if is_inlined(body, statement) {
- continue;
- }
- self.visit_coverage(coverage);
- }
- }
- }
- }
-
- fn visit_coverage(&mut self, coverage: &Coverage) {
- if self.add_missing_operands {
- match coverage.kind {
- CoverageKind::Expression { lhs, rhs, .. } => {
- self.update_from_expression_operand(u32::from(lhs));
- self.update_from_expression_operand(u32::from(rhs));
- }
- _ => {}
- }
- } else {
- match coverage.kind {
- CoverageKind::Counter { id, .. } => {
- self.update_num_counters(u32::from(id));
- }
- CoverageKind::Expression { id, .. } => {
- self.update_num_expressions(u32::from(id));
- }
- _ => {}
- }
- }
- }
-}
-
-fn coverageinfo<'tcx>(tcx: TyCtxt<'tcx>, instance_def: ty::InstanceDef<'tcx>) -> CoverageInfo {
- let mir_body = tcx.instance_mir(instance_def);
-
- let mut coverage_visitor = CoverageVisitor {
- // num_counters always has at least the `ZERO` counter.
- info: CoverageInfo { num_counters: 1, num_expressions: 0 },
- add_missing_operands: false,
- };
-
- coverage_visitor.visit_body(mir_body);
-
- coverage_visitor.add_missing_operands = true;
- coverage_visitor.visit_body(mir_body);
-
- coverage_visitor.info
-}
-
-fn covered_file_name<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> Option<Symbol> {
- if tcx.is_mir_available(def_id) {
- let body = mir_body(tcx, def_id);
- for bb_data in body.basic_blocks().iter() {
- for statement in bb_data.statements.iter() {
- if let StatementKind::Coverage(box ref coverage) = statement.kind {
- if let Some(code_region) = coverage.code_region.as_ref() {
- if is_inlined(body, statement) {
- continue;
- }
- return Some(code_region.file_name);
- }
- }
- }
- }
- }
- return None;
-}
-
-fn covered_code_regions<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> Vec<&'tcx CodeRegion> {
- let body = mir_body(tcx, def_id);
- body.basic_blocks()
- .iter()
- .map(|data| {
- data.statements.iter().filter_map(|statement| match statement.kind {
- StatementKind::Coverage(box ref coverage) => {
- if is_inlined(body, statement) {
- None
- } else {
- coverage.code_region.as_ref() // may be None
- }
- }
- _ => None,
- })
- })
- .flatten()
- .collect()
-}
-
-fn is_inlined(body: &Body<'_>, statement: &Statement<'_>) -> bool {
- let scope_data = &body.source_scopes[statement.source_info.scope];
- scope_data.inlined.is_some() || scope_data.inlined_parent_scope.is_some()
-}
-
-/// This function ensures we obtain the correct MIR for the given item irrespective of
-/// whether that means const mir or runtime mir. For `const fn` this opts for runtime
-/// mir.
-fn mir_body<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> &'tcx mir::Body<'tcx> {
- let id = ty::WithOptConstParam::unknown(def_id);
- let def = ty::InstanceDef::Item(id);
- tcx.instance_mir(def)
-}
projects / rustc.git / blobdiff