coverage: Store BCB node IDs in mappings, and resolve them in codegen

Even though the coverage graph itself is no longer available during codegen,
its nodes can still be used as opaque IDs.

1 files changed, 17 insertions, 12 deletions

diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen/covfun.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen/covfun.rs
index 460a4664615..38e7f4f21d4 100644
--- a/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen/covfun.rs
+++ b/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen/covfun.rs
@@ -11,7 +11,8 @@ use rustc_codegen_ssa::traits::{
     BaseTypeCodegenMethods, ConstCodegenMethods, StaticCodegenMethods,
 };
 use rustc_middle::mir::coverage::{
-    CovTerm, CoverageIdsInfo, Expression, FunctionCoverageInfo, Mapping, MappingKind, Op,
+    BasicCoverageBlock, CovTerm, CoverageIdsInfo, Expression, FunctionCoverageInfo, Mapping,
+    MappingKind, Op,
 };
 use rustc_middle::ty::{Instance, TyCtxt};
 use rustc_span::Span;
@@ -140,7 +141,12 @@ fn fill_region_tables<'tcx>(
     for &Mapping { ref kind, span } in &fn_cov_info.mappings {
         // If the mapping refers to counters/expressions that were removed by
         // MIR opts, replace those occurrences with zero.
-        let kind = kind.map_terms(|term| if is_zero_term(term) { CovTerm::Zero } else { term });
+        let counter_for_bcb = |bcb: BasicCoverageBlock| -> ffi::Counter {
+            let term =
+                fn_cov_info.term_for_bcb[bcb].expect("every BCB in a mapping was given a term");
+            let term = if is_zero_term(term) { CovTerm::Zero } else { term };
+            ffi::Counter::from_term(term)
+        };
 
         // Convert the `Span` into coordinates that we can pass to LLVM, or
         // discard the span if conversion fails. In rare, cases _all_ of a
@@ -154,23 +160,22 @@ fn fill_region_tables<'tcx>(
             continue;
         }
 
-        match kind {
-            MappingKind::Code(term) => {
-                code_regions
-                    .push(ffi::CodeRegion { cov_span, counter: ffi::Counter::from_term(term) });
+        match *kind {
+            MappingKind::Code { bcb } => {
+                code_regions.push(ffi::CodeRegion { cov_span, counter: counter_for_bcb(bcb) });
             }
-            MappingKind::Branch { true_term, false_term } => {
+            MappingKind::Branch { true_bcb, false_bcb } => {
                 branch_regions.push(ffi::BranchRegion {
                     cov_span,
-                    true_counter: ffi::Counter::from_term(true_term),
-                    false_counter: ffi::Counter::from_term(false_term),
+                    true_counter: counter_for_bcb(true_bcb),
+                    false_counter: counter_for_bcb(false_bcb),
                 });
             }
-            MappingKind::MCDCBranch { true_term, false_term, mcdc_params } => {
+            MappingKind::MCDCBranch { true_bcb, false_bcb, mcdc_params } => {
                 mcdc_branch_regions.push(ffi::MCDCBranchRegion {
                     cov_span,
-                    true_counter: ffi::Counter::from_term(true_term),
-                    false_counter: ffi::Counter::from_term(false_term),
+                    true_counter: counter_for_bcb(true_bcb),
+                    false_counter: counter_for_bcb(false_bcb),
                     mcdc_branch_params: ffi::mcdc::BranchParameters::from(mcdc_params),
                 });
             }