Make source-based code coverage compatible with MIR inlining

When codegenning code coverage use the instance that coverage data was
originally generated for, to ensure basic level of compatibility with
MIR inlining.

compiler/rustc_mir/src/transform/coverage/query.rs

@@ -1,8 +1,7 @@
 use super::*;
 
 use rustc_middle::mir::coverage::*;
-use rustc_middle::mir::visit::Visitor;
-use rustc_middle::mir::{self, Coverage, CoverageInfo, Location};
+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;
@@ -85,10 +84,21 @@ impl CoverageVisitor {
             }
         }
     }
-}
 
-impl Visitor<'_> for CoverageVisitor {
-    fn visit_coverage(&mut self, coverage: &Coverage, _location: Location) {
+    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, .. } => {
@@ -129,10 +139,14 @@ fn coverageinfo_from_mir<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> CoverageInfo
 }
 
 fn covered_file_name<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> Option<Symbol> {
-    for bb_data in mir_body(tcx, def_id).basic_blocks().iter() {
+    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);
                 }
             }
@@ -151,13 +165,17 @@ fn mir_body<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> &'tcx mir::Body<'tcx> {
 }
 
 fn covered_code_regions<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> Vec<&'tcx CodeRegion> {
-    mir_body(tcx, def_id)
-        .basic_blocks()
+    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) => {
-                    coverage.code_region.as_ref() // may be None
+                    if is_inlined(body, statement) {
+                        None
+                    } else {
+                        coverage.code_region.as_ref() // may be None
+                    }
                 }
                 _ => None,
             })
@@ -165,3 +183,8 @@ fn covered_code_regions<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> Vec<&'tcx Cod
         .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()
+}