(> 1e6e3fb)remove injected statements for sum expressions of bcbs

Author: zhuyunxing

compiler/rustc_mir_transform/src/coverage/mod.rs

@@ -99,14 +99,7 @@ fn instrument_function_for_coverage<'tcx>(tcx: TyCtxt<'tcx>, mir_body: &mut mir:
     let mut coverage_counters =
         CoverageCounters::make_bcb_counters(&basic_coverage_blocks, bcb_has_counter_mappings);
 
-    let mappings = create_mappings(
-        mir_body,
-        tcx,
-        &hir_info,
-        &extracted_mappings,
-        &basic_coverage_blocks,
-        &mut coverage_counters,
-    );
+    let mappings = create_mappings(tcx, &hir_info, &extracted_mappings, &mut coverage_counters);
     if mappings.is_empty() {
         // No spans could be converted into valid mappings, so skip this function.
         debug!("no spans could be converted into valid mappings; skipping");
@@ -145,11 +138,9 @@ fn instrument_function_for_coverage<'tcx>(tcx: TyCtxt<'tcx>, mir_body: &mut mir:
 /// Precondition: All BCBs corresponding to those spans have been given
 /// coverage counters.
 fn create_mappings<'tcx>(
-    mir_body: &mut mir::Body<'tcx>,
     tcx: TyCtxt<'tcx>,
     hir_info: &ExtractedHirInfo,
     extracted_mappings: &ExtractedMappings,
-    basic_coverage_blocks: &CoverageGraph,
     coverage_counters: &mut CoverageCounters,
 ) -> Vec<Mapping> {
     let source_map = tcx.sess.source_map();
@@ -198,7 +189,7 @@ fn create_mappings<'tcx>(
             Some(Mapping { kind, code_region })
         },
     ));
-    let mut term_for_bcbs = |bcbs: &[BasicCoverageBlock]| {
+    let mut term_for_sum_of_bcbs = |bcbs: &[BasicCoverageBlock]| {
         let counters = bcbs
             .into_iter()
             .copied()
@@ -210,28 +201,15 @@ fn create_mappings<'tcx>(
             .into_iter()
             .fold(None, |acc, val| Some(coverage_counters.make_sum_expression(acc, val)))
             .expect("counters must be non-empty");
-        // Since the counter is a sum of multiple counters, it should be marked used in
-        // all associated bcbs in case it were markered as `Zero`.
-        if bcbs.len() > 1
-            && let counters::BcbCounter::Expression { id } = counter
-        {
-            for &bcb in bcbs {
-                inject_statement(
-                    mir_body,
-                    CoverageKind::ExpressionUsed { id },
-                    basic_coverage_blocks[bcb].leader_bb(),
-                );
-            }
-        }
         counter.as_term()
     };
 
     // MCDC branch mappings are appended with their decisions in case decisions were ignored.
     mappings.extend(mcdc_degraded_branches.iter().filter_map(
         |&mappings::MCDCBranch { span, ref true_bcbs, ref false_bcbs, condition_info: _ }| {
             let code_region = region_for_span(span)?;
-            let true_term = term_for_bcbs(true_bcbs);
-            let false_term = term_for_bcbs(false_bcbs);
+            let true_term = term_for_sum_of_bcbs(true_bcbs);
+            let false_term = term_for_sum_of_bcbs(false_bcbs);
             Some(Mapping { kind: MappingKind::Branch { true_term, false_term }, code_region })
         },
     ));
@@ -243,8 +221,8 @@ fn create_mappings<'tcx>(
             .filter_map(
                 |&mappings::MCDCBranch { span, ref true_bcbs, ref false_bcbs, condition_info }| {
                     let code_region = region_for_span(span)?;
-                    let true_term = term_for_bcbs(true_bcbs);
-                    let false_term = term_for_bcbs(false_bcbs);
+                    let true_term = term_for_sum_of_bcbs(true_bcbs);
+                    let false_term = term_for_sum_of_bcbs(false_bcbs);
                     Some(Mapping {
                         kind: MappingKind::MCDCBranch {
                             true_term,