coverage: Remove FunctionCoverageCollector

The information that was being collected by this builder type is now collected
by the `coverage_ids_info` query instead.

Author: Zalathar

compiler/rustc_codegen_llvm/src/coverageinfo/map_data.rs

@@ -3,70 +3,30 @@ use rustc_middle::mir::coverage::{
     CovTerm, CoverageIdsInfo, Expression, FunctionCoverageInfo, Mapping, MappingKind, Op,
     SourceRegion,
 };
-use rustc_middle::ty::Instance;
-use tracing::debug;
 
 use crate::coverageinfo::ffi::{Counter, CounterExpression, ExprKind};
 
-/// Holds all of the coverage mapping data associated with a function instance,
-/// collected during traversal of `Coverage` statements in the function's MIR.
-#[derive(Debug)]
-pub(crate) struct FunctionCoverageCollector<'tcx> {
-    /// Coverage info that was attached to this function by the instrumentor.
-    function_coverage_info: &'tcx FunctionCoverageInfo,
+pub(crate) struct FunctionCoverage<'tcx> {
+    pub(crate) function_coverage_info: &'tcx FunctionCoverageInfo,
     ids_info: &'tcx CoverageIdsInfo,
     is_used: bool,
 }
 
-impl<'tcx> FunctionCoverageCollector<'tcx> {
-    /// Creates a new set of coverage data for a used (called) function.
-    pub(crate) fn new(
-        instance: Instance<'tcx>,
-        function_coverage_info: &'tcx FunctionCoverageInfo,
-        ids_info: &'tcx CoverageIdsInfo,
-    ) -> Self {
-        Self::create(instance, function_coverage_info, ids_info, true)
-    }
-
-    /// Creates a new set of coverage data for an unused (never called) function.
-    pub(crate) fn unused(
-        instance: Instance<'tcx>,
+impl<'tcx> FunctionCoverage<'tcx> {
+    pub(crate) fn new_used(
         function_coverage_info: &'tcx FunctionCoverageInfo,
         ids_info: &'tcx CoverageIdsInfo,
     ) -> Self {
-        Self::create(instance, function_coverage_info, ids_info, false)
+        Self { function_coverage_info, ids_info, is_used: true }
     }
 
-    fn create(
-        instance: Instance<'tcx>,
+    pub(crate) fn new_unused(
         function_coverage_info: &'tcx FunctionCoverageInfo,
         ids_info: &'tcx CoverageIdsInfo,
-        is_used: bool,
     ) -> Self {
-        let num_counters = function_coverage_info.num_counters;
-        let num_expressions = function_coverage_info.expressions.len();
-        debug!(
-            "FunctionCoverage::create(instance={instance:?}) has \
-            num_counters={num_counters}, num_expressions={num_expressions}, is_used={is_used}"
-        );
-
-        Self { function_coverage_info, ids_info, is_used }
-    }
-
-    pub(crate) fn into_finished(self) -> FunctionCoverage<'tcx> {
-        let FunctionCoverageCollector { function_coverage_info, ids_info, is_used, .. } = self;
-
-        FunctionCoverage { function_coverage_info, ids_info, is_used }
+        Self { function_coverage_info, ids_info, is_used: false }
     }
-}
-
-pub(crate) struct FunctionCoverage<'tcx> {
-    pub(crate) function_coverage_info: &'tcx FunctionCoverageInfo,
-    ids_info: &'tcx CoverageIdsInfo,
-    is_used: bool,
-}
 
-impl<'tcx> FunctionCoverage<'tcx> {
     /// Returns true for a used (called) function, and false for an unused function.
     pub(crate) fn is_used(&self) -> bool {
         self.is_used

compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs

@@ -20,7 +20,7 @@ use rustc_target::spec::HasTargetSpec;
 use tracing::debug;
 
 use crate::common::CodegenCx;
-use crate::coverageinfo::map_data::{FunctionCoverage, FunctionCoverageCollector};
+use crate::coverageinfo::map_data::FunctionCoverage;
 use crate::coverageinfo::{ffi, llvm_cov};
 use crate::llvm;
 
@@ -63,16 +63,11 @@ pub(crate) fn finalize(cx: &CodegenCx<'_, '_>) {
         None => return,
     };
     if function_coverage_map.is_empty() {
-        // This module has no functions with coverage instrumentation
+        // This CGU has no functions with coverage instrumentation.
         return;
     }
 
-    let function_coverage_entries = function_coverage_map
-        .into_iter()
-        .map(|(instance, function_coverage)| (instance, function_coverage.into_finished()))
-        .collect::<Vec<_>>();
-
-    let all_file_names = function_coverage_entries
+    let all_file_names = function_coverage_map
         .iter()
         .map(|(_, fn_cov)| fn_cov.function_coverage_info.body_span)
         .map(|span| span_file_name(tcx, span));
@@ -92,7 +87,7 @@ pub(crate) fn finalize(cx: &CodegenCx<'_, '_>) {
     let mut unused_function_names = Vec::new();
 
     // Encode coverage mappings and generate function records
-    for (instance, function_coverage) in function_coverage_entries {
+    for (instance, function_coverage) in function_coverage_map {
         debug!("Generate function coverage for {}, {:?}", cx.codegen_unit.name(), instance);
 
         let mangled_function_name = tcx.symbol_name(instance).name;
@@ -536,11 +531,7 @@ fn add_unused_function_coverage<'tcx>(
     );
 
     // An unused function's mappings will all be rewritten to map to zero.
-    let function_coverage = FunctionCoverageCollector::unused(
-        instance,
-        function_coverage_info,
-        tcx.coverage_ids_info(instance.def),
-    );
-
+    let function_coverage =
+        FunctionCoverage::new_unused(function_coverage_info, tcx.coverage_ids_info(instance.def));
     cx.coverage_cx().function_coverage_map.borrow_mut().insert(instance, function_coverage);
 }

compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs

@@ -13,7 +13,7 @@ use tracing::{debug, instrument};
 
 use crate::builder::Builder;
 use crate::common::CodegenCx;
-use crate::coverageinfo::map_data::FunctionCoverageCollector;
+use crate::coverageinfo::map_data::FunctionCoverage;
 use crate::llvm;
 
 pub(crate) mod ffi;
@@ -24,8 +24,7 @@ mod mapgen;
 /// Extra per-CGU context/state needed for coverage instrumentation.
 pub(crate) struct CguCoverageContext<'ll, 'tcx> {
     /// Coverage data for each instrumented function identified by DefId.
-    pub(crate) function_coverage_map:
-        RefCell<FxIndexMap<Instance<'tcx>, FunctionCoverageCollector<'tcx>>>,
+    pub(crate) function_coverage_map: RefCell<FxIndexMap<Instance<'tcx>, FunctionCoverage<'tcx>>>,
     pub(crate) pgo_func_name_var_map: RefCell<FxHashMap<Instance<'tcx>, &'ll llvm::Value>>,
     pub(crate) mcdc_condition_bitmap_map: RefCell<FxHashMap<Instance<'tcx>, Vec<&'ll llvm::Value>>>,
 
@@ -42,9 +41,7 @@ impl<'ll, 'tcx> CguCoverageContext<'ll, 'tcx> {
         }
     }
 
-    fn take_function_coverage_map(
-        &self,
-    ) -> FxIndexMap<Instance<'tcx>, FunctionCoverageCollector<'tcx>> {
+    fn take_function_coverage_map(&self) -> FxIndexMap<Instance<'tcx>, FunctionCoverage<'tcx>> {
         self.function_coverage_map.replace(FxIndexMap::default())
     }
 
@@ -161,8 +158,7 @@ impl<'tcx> CoverageInfoBuilderMethods<'tcx> for Builder<'_, '_, 'tcx> {
         // This includes functions that were not partitioned into this CGU,
         // but were MIR-inlined into one of this CGU's functions.
         coverage_cx.function_coverage_map.borrow_mut().entry(instance).or_insert_with(|| {
-            FunctionCoverageCollector::new(
-                instance,
+            FunctionCoverage::new_used(
                 function_coverage_info,
                 bx.tcx.coverage_ids_info(instance.def),
             )