Rollup merge of #98868 - tmiasko:unreachable-coverage, r=wesleywiser

Fix unreachable coverage generation for inlined functions

To generate a function coverage we need at least one coverage counter,
so a coverage from unreachable blocks is retained only when some live
counters remain.

The previous implementation incorrectly retained unreachable coverage,
because it didn't account for the fact that those live counters can
belong to another function due to inlining.

Fixes #98833.

1 files changed, 2 insertions, 5 deletions

diff --git a/compiler/rustc_codegen_ssa/src/mir/coverageinfo.rs b/compiler/rustc_codegen_ssa/src/mir/coverageinfo.rs
index a283bf1de76..f1fe495282a 100644
--- a/compiler/rustc_codegen_ssa/src/mir/coverageinfo.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/coverageinfo.rs
@@ -9,11 +9,8 @@ use super::FunctionCx;
 impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
     pub fn codegen_coverage(&self, bx: &mut Bx, coverage: Coverage, scope: SourceScope) {
         // Determine the instance that coverage data was originally generated for.
-        let scope_data = &self.mir.source_scopes[scope];
-        let instance = if let Some((inlined_instance, _)) = scope_data.inlined {
-            self.monomorphize(inlined_instance)
-        } else if let Some(inlined_scope) = scope_data.inlined_parent_scope {
-            self.monomorphize(self.mir.source_scopes[inlined_scope].inlined.unwrap().0)
+        let instance = if let Some(inlined) = scope.inlined_instance(&self.mir.source_scopes) {
+            self.monomorphize(inlined)
         } else {
             self.instance
         };