coverage: Pull function source hash out of map_data.rs

Author: Zalathar

compiler/rustc_codegen_llvm/src/coverageinfo/map_data.rs

@@ -1,6 +1,7 @@
 use rustc_middle::mir::coverage::{CoverageIdsInfo, FunctionCoverageInfo};
 
 pub(crate) struct FunctionCoverage<'tcx> {
+    #[expect(unused)] // This whole file gets deleted later in the same PR.
     pub(crate) function_coverage_info: &'tcx FunctionCoverageInfo,
     /// If `None`, the corresponding function is unused.
     ids_info: Option<&'tcx CoverageIdsInfo>,
@@ -22,10 +23,4 @@ impl<'tcx> FunctionCoverage<'tcx> {
     pub(crate) fn is_used(&self) -> bool {
         self.ids_info.is_some()
     }
-
-    /// Return the source hash, generated from the HIR node structure, and used to indicate whether
-    /// or not the source code structure changed between different compilations.
-    pub(crate) fn source_hash(&self) -> u64 {
-        if self.is_used() { self.function_coverage_info.function_source_hash } else { 0 }
-    }
 }

compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs

@@ -81,7 +81,8 @@ pub(crate) fn finalize(cx: &CodegenCx<'_, '_>) {
         // instances were visited during codegen.
         .sorted_by_cached_key(|&(instance, _)| tcx.symbol_name(instance).name)
         .filter_map(|(instance, function_coverage)| {
-            prepare_covfun_record(tcx, &mut global_file_table, instance, &function_coverage)
+            let is_used = function_coverage.is_used();
+            prepare_covfun_record(tcx, &mut global_file_table, instance, is_used)
         })
         .collect::<Vec<_>>();
 

compiler/rustc_codegen_llvm/src/coverageinfo/mapgen/covfun.rs

@@ -19,7 +19,6 @@ use rustc_target::spec::HasTargetSpec;
 use tracing::debug;
 
 use crate::common::CodegenCx;
-use crate::coverageinfo::map_data::FunctionCoverage;
 use crate::coverageinfo::mapgen::{GlobalFileTable, VirtualFileMapping, span_file_name};
 use crate::coverageinfo::{ffi, llvm_cov};
 use crate::llvm;
@@ -49,17 +48,17 @@ pub(crate) fn prepare_covfun_record<'tcx>(
     tcx: TyCtxt<'tcx>,
     global_file_table: &mut GlobalFileTable,
     instance: Instance<'tcx>,
-    function_coverage: &FunctionCoverage<'tcx>,
+    is_used: bool,
 ) -> Option<CovfunRecord<'tcx>> {
     let fn_cov_info = tcx.instance_mir(instance.def).function_coverage_info.as_deref()?;
     let ids_info = tcx.coverage_ids_info(instance.def);
 
-    let expressions = prepare_expressions(fn_cov_info, ids_info, function_coverage.is_used());
+    let expressions = prepare_expressions(fn_cov_info, ids_info, is_used);
 
     let mut covfun = CovfunRecord {
         mangled_function_name: tcx.symbol_name(instance).name,
-        source_hash: function_coverage.source_hash(),
-        is_used: function_coverage.is_used(),
+        source_hash: if is_used { fn_cov_info.function_source_hash } else { 0 },
+        is_used,
         virtual_file_mapping: VirtualFileMapping::default(),
         expressions,
         regions: ffi::Regions::default(),