4 files changed, 30 insertions, 28 deletions
diff --git a/compiler/rustc_middle/src/mir/coverage.rs b/compiler/rustc_middle/src/mir/coverage.rs
index 164a17ff77a..2587a6eae1a 100644
--- a/compiler/rustc_middle/src/mir/coverage.rs
+++ b/compiler/rustc_middle/src/mir/coverage.rs
@@ -61,11 +61,13 @@ impl Debug for CovTerm {
 
 #[derive(Clone, PartialEq, TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable, TypeVisitable)]
 pub enum CoverageKind {
-    Counter {
-        /// ID of this counter within its enclosing function.
-        /// Expressions in the same function can refer to it as an operand.
-        id: CounterId,
-    },
+    /// Marks the point in MIR control flow represented by a coverage counter.
+    ///
+    /// This is eventually lowered to `llvm.instrprof.increment` in LLVM IR.
+    ///
+    /// If this statement does not survive MIR optimizations, any mappings that
+    /// refer to this counter can have those references simplified to zero.
+    CounterIncrement { id: CounterId },
     Expression {
         /// ID of this coverage-counter expression within its enclosing function.
         /// Other expressions in the same function can refer to it as an operand.
@@ -74,14 +76,13 @@ pub enum CoverageKind {
         op: Op,
         rhs: CovTerm,
     },
-    Unreachable,
 }
 
 impl Debug for CoverageKind {
     fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
         use CoverageKind::*;
         match self {
-            Counter { id } => write!(fmt, "Counter({:?})", id.index()),
+            CounterIncrement { id } => write!(fmt, "CounterIncrement({:?})", id.index()),
             Expression { id, lhs, op, rhs } => write!(
                 fmt,
                 "Expression({:?}) = {:?} {} {:?}",
@@ -93,7 +94,6 @@ impl Debug for CoverageKind {
                 },
                 rhs,
             ),
-            Unreachable => write!(fmt, "Unreachable"),
         }
     }
 }
@@ -158,4 +158,6 @@ pub struct FunctionCoverageInfo {
     pub function_source_hash: u64,
     pub num_counters: usize,
     pub num_expressions: usize,
+
+    pub mappings: Vec<Mapping>,
 }
diff --git a/compiler/rustc_middle/src/mir/pretty.rs b/compiler/rustc_middle/src/mir/pretty.rs
index c5e3ee575e1..11269e749f8 100644
--- a/compiler/rustc_middle/src/mir/pretty.rs
+++ b/compiler/rustc_middle/src/mir/pretty.rs
@@ -493,6 +493,24 @@ pub fn write_mir_intro<'tcx>(
     // Add an empty line before the first block is printed.
     writeln!(w)?;
 
+    if let Some(function_coverage_info) = &body.function_coverage_info {
+        write_function_coverage_info(function_coverage_info, w)?;
+    }
+
+    Ok(())
+}
+
+fn write_function_coverage_info(
+    function_coverage_info: &coverage::FunctionCoverageInfo,
+    w: &mut dyn io::Write,
+) -> io::Result<()> {
+    let coverage::FunctionCoverageInfo { mappings, .. } = function_coverage_info;
+
+    for coverage::Mapping { term, code_region } in mappings {
+        writeln!(w, "{INDENT}coverage {term:?} => {code_region:?};")?;
+    }
+    writeln!(w)?;
+
     Ok(())
 }
 
@@ -685,13 +703,7 @@ impl Debug for Statement<'_> {
             AscribeUserType(box (ref place, ref c_ty), ref variance) => {
                 write!(fmt, "AscribeUserType({place:?}, {variance:?}, {c_ty:?})")
             }
-            Coverage(box mir::Coverage { ref kind, ref code_regions }) => {
-                if code_regions.is_empty() {
-                    write!(fmt, "Coverage::{kind:?}")
-                } else {
-                    write!(fmt, "Coverage::{kind:?} for {code_regions:?}")
-                }
-            }
+            Coverage(box mir::Coverage { ref kind }) => write!(fmt, "Coverage::{kind:?}"),
             Intrinsic(box ref intrinsic) => write!(fmt, "{intrinsic}"),
             ConstEvalCounter => write!(fmt, "ConstEvalCounter"),
             Nop => write!(fmt, "nop"),
diff --git a/compiler/rustc_middle/src/mir/syntax.rs b/compiler/rustc_middle/src/mir/syntax.rs
index c7d99648f1e..77b26e0a4cd 100644
--- a/compiler/rustc_middle/src/mir/syntax.rs
+++ b/compiler/rustc_middle/src/mir/syntax.rs
@@ -5,7 +5,7 @@
 
 use super::{BasicBlock, Const, Local, UserTypeProjection};
 
-use crate::mir::coverage::{CodeRegion, CoverageKind};
+use crate::mir::coverage::CoverageKind;
 use crate::traits::Reveal;
 use crate::ty::adjustment::PointerCoercion;
 use crate::ty::GenericArgsRef;
@@ -514,7 +514,6 @@ pub enum FakeReadCause {
 #[derive(TypeFoldable, TypeVisitable)]
 pub struct Coverage {
     pub kind: CoverageKind,
-    pub code_regions: Vec<CodeRegion>,
 }
 
 #[derive(Clone, Debug, PartialEq, TyEncodable, TyDecodable, Hash, HashStable)]
diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs
index ed0f73fcf2f..afe94d10752 100644
--- a/compiler/rustc_middle/src/query/mod.rs
+++ b/compiler/rustc_middle/src/query/mod.rs
@@ -581,17 +581,6 @@ rustc_queries! {
         arena_cache
     }
 
-    /// Returns the `CodeRegions` for a function that has instrumented coverage, in case the
-    /// function was optimized out before codegen, and before being added to the Coverage Map.
-    query covered_code_regions(key: DefId) -> &'tcx Vec<&'tcx mir::coverage::CodeRegion> {
-        desc {
-            |tcx| "retrieving the covered `CodeRegion`s, if instrumented, for `{}`",
-            tcx.def_path_str(key)
-        }
-        arena_cache
-        cache_on_disk_if { key.is_local() }
-    }
-
     /// The `DefId` is the `DefId` of the containing MIR body. Promoteds do not have their own
     /// `DefId`. This function returns all promoteds in the specified body. The body references
     /// promoteds by the `DefId` and the `mir::Promoted` index. This is necessary, because