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| author | Camille GILLOT <gillot.camille@gmail.com> | 2021-01-01 01:53:25 +0100 |
|---|---|---|
| committer | Camille GILLOT <gillot.camille@gmail.com> | 2021-09-07 00:43:14 +0200 |
| commit | bba4be681d664a50ab307ec732f957c02255e067 (patch) | |
| tree | d56899ff2ba1bcf004901eac1e155b2656a5e4fd /compiler/rustc_mir/src/transform/coverage/query.rs | |
| parent | 31a61ccc38201a13c2549b20772daf15ce0e0309 (diff) | |
| download | rust-bba4be681d664a50ab307ec732f957c02255e067.tar.gz rust-bba4be681d664a50ab307ec732f957c02255e067.zip | |
Move rustc_mir::transform to rustc_mir_transform.
Diffstat (limited to 'compiler/rustc_mir/src/transform/coverage/query.rs')
| -rw-r--r-- | compiler/rustc_mir/src/transform/coverage/query.rs | 191 |
1 files changed, 0 insertions, 191 deletions
diff --git a/compiler/rustc_mir/src/transform/coverage/query.rs b/compiler/rustc_mir/src/transform/coverage/query.rs deleted file mode 100644 index 760f16eae6b..00000000000 --- a/compiler/rustc_mir/src/transform/coverage/query.rs +++ /dev/null @@ -1,191 +0,0 @@ -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) -} |
