Rollup merge of #78300 - richkadel:coverage-cx, r=wesleywiser

Make codegen coverage_context optional, and check

Addresses Issue #78286

Libraries compiled with coverage and linked with out enabling coverage
would fail when attempting to add the library's coverage statements to
the codegen coverage context (None).

Now, if coverage statements are encountered while compiling / linking
with `-Z instrument-coverage` disabled, codegen will *not* attempt to
add code regions to a coverage map, and it will not inject the LLVM
instrprof_increment intrinsic calls.

1 files changed, 47 insertions, 32 deletions

diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs
index 2bd37bf9c4f..7fdbe1a5512 100644
--- a/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs
+++ b/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs
@@ -64,17 +64,22 @@ impl CoverageInfoBuilderMethods<'tcx> for Builder<'a, 'll, 'tcx> {
         function_source_hash: u64,
         id: CounterValueReference,
         region: CodeRegion,
-    ) {
-        debug!(
-            "adding counter to coverage_regions: instance={:?}, function_source_hash={}, id={:?}, \
-             at {:?}",
-            instance, function_source_hash, id, region,
-        );
-        let mut coverage_regions = self.coverage_context().function_coverage_map.borrow_mut();
-        coverage_regions
-            .entry(instance)
-            .or_insert_with(|| FunctionCoverage::new(self.tcx, instance))
-            .add_counter(function_source_hash, id, region);
+    ) -> bool {
+        if let Some(coverage_context) = self.coverage_context() {
+            debug!(
+                "adding counter to coverage_regions: instance={:?}, function_source_hash={}, id={:?}, \
+                at {:?}",
+                instance, function_source_hash, id, region,
+            );
+            let mut coverage_regions = coverage_context.function_coverage_map.borrow_mut();
+            coverage_regions
+                .entry(instance)
+                .or_insert_with(|| FunctionCoverage::new(self.tcx, instance))
+                .add_counter(function_source_hash, id, region);
+            true
+        } else {
+            false
+        }
     }
 
     fn add_counter_expression_region(
@@ -85,29 +90,39 @@ impl CoverageInfoBuilderMethods<'tcx> for Builder<'a, 'll, 'tcx> {
         op: Op,
         rhs: ExpressionOperandId,
         region: CodeRegion,
-    ) {
-        debug!(
-            "adding counter expression to coverage_regions: instance={:?}, id={:?}, {:?} {:?} {:?}, \
-             at {:?}",
-            instance, id, lhs, op, rhs, region,
-        );
-        let mut coverage_regions = self.coverage_context().function_coverage_map.borrow_mut();
-        coverage_regions
-            .entry(instance)
-            .or_insert_with(|| FunctionCoverage::new(self.tcx, instance))
-            .add_counter_expression(id, lhs, op, rhs, region);
+    ) -> bool {
+        if let Some(coverage_context) = self.coverage_context() {
+            debug!(
+                "adding counter expression to coverage_regions: instance={:?}, id={:?}, {:?} {:?} {:?}, \
+                at {:?}",
+                instance, id, lhs, op, rhs, region,
+            );
+            let mut coverage_regions = coverage_context.function_coverage_map.borrow_mut();
+            coverage_regions
+                .entry(instance)
+                .or_insert_with(|| FunctionCoverage::new(self.tcx, instance))
+                .add_counter_expression(id, lhs, op, rhs, region);
+            true
+        } else {
+            false
+        }
     }
 
-    fn add_unreachable_region(&mut self, instance: Instance<'tcx>, region: CodeRegion) {
-        debug!(
-            "adding unreachable code to coverage_regions: instance={:?}, at {:?}",
-            instance, region,
-        );
-        let mut coverage_regions = self.coverage_context().function_coverage_map.borrow_mut();
-        coverage_regions
-            .entry(instance)
-            .or_insert_with(|| FunctionCoverage::new(self.tcx, instance))
-            .add_unreachable_region(region);
+    fn add_unreachable_region(&mut self, instance: Instance<'tcx>, region: CodeRegion) -> bool {
+        if let Some(coverage_context) = self.coverage_context() {
+            debug!(
+                "adding unreachable code to coverage_regions: instance={:?}, at {:?}",
+                instance, region,
+            );
+            let mut coverage_regions = coverage_context.function_coverage_map.borrow_mut();
+            coverage_regions
+                .entry(instance)
+                .or_insert_with(|| FunctionCoverage::new(self.tcx, instance))
+                .add_unreachable_region(region);
+            true
+        } else {
+            false
+        }
     }
 }