Merge pull request #4518 from rust-lang/rustup-2025-08-09

Automatic Rustup

12 files changed, 144 insertions, 71 deletions

diff --git a/compiler/rustc_codegen_ssa/src/assert_module_sources.rs b/compiler/rustc_codegen_ssa/src/assert_module_sources.rs
index 3710625ac12..43e1e135a66 100644
--- a/compiler/rustc_codegen_ssa/src/assert_module_sources.rs
+++ b/compiler/rustc_codegen_ssa/src/assert_module_sources.rs
@@ -69,6 +69,15 @@ pub fn assert_module_sources(tcx: TyCtxt<'_>, set_reuse: &dyn Fn(&mut CguReuseTr
 
         set_reuse(&mut ams.cgu_reuse_tracker);
 
+        if tcx.sess.opts.unstable_opts.print_mono_items
+            && let Some(data) = &ams.cgu_reuse_tracker.data
+        {
+            data.actual_reuse.items().all(|(cgu, reuse)| {
+                println!("CGU_REUSE {cgu} {reuse}");
+                true
+            });
+        }
+
         ams.cgu_reuse_tracker.check_expected_reuse(tcx.sess);
     });
 }
diff --git a/compiler/rustc_codegen_ssa/src/back/apple.rs b/compiler/rustc_codegen_ssa/src/back/apple.rs
index d242efaf4fd..2f68bad1695 100644
--- a/compiler/rustc_codegen_ssa/src/back/apple.rs
+++ b/compiler/rustc_codegen_ssa/src/back/apple.rs
@@ -17,7 +17,7 @@ mod tests;
 
 /// The canonical name of the desired SDK for a given target.
 pub(super) fn sdk_name(target: &Target) -> &'static str {
-    match (&*target.os, &*target.abi) {
+    match (&*target.os, &*target.env) {
         ("macos", "") => "MacOSX",
         ("ios", "") => "iPhoneOS",
         ("ios", "sim") => "iPhoneSimulator",
@@ -34,7 +34,7 @@ pub(super) fn sdk_name(target: &Target) -> &'static str {
 }
 
 pub(super) fn macho_platform(target: &Target) -> u32 {
-    match (&*target.os, &*target.abi) {
+    match (&*target.os, &*target.env) {
         ("macos", _) => object::macho::PLATFORM_MACOS,
         ("ios", "macabi") => object::macho::PLATFORM_MACCATALYST,
         ("ios", "sim") => object::macho::PLATFORM_IOSSIMULATOR,
diff --git a/compiler/rustc_codegen_ssa/src/back/link.rs b/compiler/rustc_codegen_ssa/src/back/link.rs
index b69fbf61185..6e21f54587f 100644
--- a/compiler/rustc_codegen_ssa/src/back/link.rs
+++ b/compiler/rustc_codegen_ssa/src/back/link.rs
@@ -3026,7 +3026,7 @@ pub(crate) fn are_upstream_rust_objects_already_included(sess: &Session) -> bool
 /// We need to communicate five things to the linker on Apple/Darwin targets:
 /// - The architecture.
 /// - The operating system (and that it's an Apple platform).
-/// - The environment / ABI.
+/// - The environment.
 /// - The deployment target.
 /// - The SDK version.
 fn add_apple_link_args(cmd: &mut dyn Linker, sess: &Session, flavor: LinkerFlavor) {
@@ -3040,7 +3040,7 @@ fn add_apple_link_args(cmd: &mut dyn Linker, sess: &Session, flavor: LinkerFlavo
     // `sess.target.arch` (`target_arch`) is not detailed enough.
     let llvm_arch = sess.target.llvm_target.split_once('-').expect("LLVM target must have arch").0;
     let target_os = &*sess.target.os;
-    let target_abi = &*sess.target.abi;
+    let target_env = &*sess.target.env;
 
     // The architecture name to forward to the linker.
     //
@@ -3091,14 +3091,14 @@ fn add_apple_link_args(cmd: &mut dyn Linker, sess: &Session, flavor: LinkerFlavo
         // > - visionos-simulator
         // > - xros-simulator
         // > - driverkit
-        let platform_name = match (target_os, target_abi) {
+        let platform_name = match (target_os, target_env) {
             (os, "") => os,
             ("ios", "macabi") => "mac-catalyst",
             ("ios", "sim") => "ios-simulator",
             ("tvos", "sim") => "tvos-simulator",
             ("watchos", "sim") => "watchos-simulator",
             ("visionos", "sim") => "visionos-simulator",
-            _ => bug!("invalid OS/ABI combination for Apple target: {target_os}, {target_abi}"),
+            _ => bug!("invalid OS/env combination for Apple target: {target_os}, {target_env}"),
         };
 
         let min_version = sess.apple_deployment_target().fmt_full().to_string();
diff --git a/compiler/rustc_codegen_ssa/src/back/linker.rs b/compiler/rustc_codegen_ssa/src/back/linker.rs
index 050797354b4..df1e91b12f9 100644
--- a/compiler/rustc_codegen_ssa/src/back/linker.rs
+++ b/compiler/rustc_codegen_ssa/src/back/linker.rs
@@ -1805,11 +1805,18 @@ pub(crate) fn exported_symbols(
             .collect();
     }
 
-    if let CrateType::ProcMacro = crate_type {
+    let mut symbols = if let CrateType::ProcMacro = crate_type {
         exported_symbols_for_proc_macro_crate(tcx)
     } else {
         exported_symbols_for_non_proc_macro(tcx, crate_type)
+    };
+
+    if crate_type == CrateType::Dylib || crate_type == CrateType::ProcMacro {
+        let metadata_symbol_name = exported_symbols::metadata_symbol_name(tcx);
+        symbols.push((metadata_symbol_name, SymbolExportKind::Data));
     }
+
+    symbols
 }
 
 fn exported_symbols_for_non_proc_macro(
@@ -1842,12 +1849,8 @@ fn exported_symbols_for_proc_macro_crate(tcx: TyCtxt<'_>) -> Vec<(String, Symbol
 
     let stable_crate_id = tcx.stable_crate_id(LOCAL_CRATE);
     let proc_macro_decls_name = tcx.sess.generate_proc_macro_decls_symbol(stable_crate_id);
-    let metadata_symbol_name = exported_symbols::metadata_symbol_name(tcx);
 
-    vec![
-        (proc_macro_decls_name, SymbolExportKind::Data),
-        (metadata_symbol_name, SymbolExportKind::Data),
-    ]
+    vec![(proc_macro_decls_name, SymbolExportKind::Data)]
 }
 
 pub(crate) fn linked_symbols(
diff --git a/compiler/rustc_codegen_ssa/src/back/symbol_export.rs b/compiler/rustc_codegen_ssa/src/back/symbol_export.rs
index 4b4b39f5353..7e124f65324 100644
--- a/compiler/rustc_codegen_ssa/src/back/symbol_export.rs
+++ b/compiler/rustc_codegen_ssa/src/back/symbol_export.rs
@@ -8,7 +8,7 @@ use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, LOCAL_CRATE, LocalDefId};
 use rustc_middle::bug;
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use rustc_middle::middle::exported_symbols::{
-    ExportedSymbol, SymbolExportInfo, SymbolExportKind, SymbolExportLevel, metadata_symbol_name,
+    ExportedSymbol, SymbolExportInfo, SymbolExportKind, SymbolExportLevel,
 };
 use rustc_middle::query::LocalCrate;
 use rustc_middle::ty::{self, GenericArgKind, GenericArgsRef, Instance, SymbolName, Ty, TyCtxt};
@@ -289,23 +289,6 @@ fn exported_non_generic_symbols_provider_local<'tcx>(
         }));
     }
 
-    if tcx.crate_types().contains(&CrateType::Dylib)
-        || tcx.crate_types().contains(&CrateType::ProcMacro)
-    {
-        let symbol_name = metadata_symbol_name(tcx);
-        let exported_symbol = ExportedSymbol::NoDefId(SymbolName::new(tcx, &symbol_name));
-
-        symbols.push((
-            exported_symbol,
-            SymbolExportInfo {
-                level: SymbolExportLevel::C,
-                kind: SymbolExportKind::Data,
-                used: true,
-                rustc_std_internal_symbol: false,
-            },
-        ));
-    }
-
     // Sort so we get a stable incr. comp. hash.
     symbols.sort_by_cached_key(|s| s.0.symbol_name_for_local_instance(tcx));
 
diff --git a/compiler/rustc_codegen_ssa/src/errors.rs b/compiler/rustc_codegen_ssa/src/errors.rs
index 3d787d8bdbd..af4adcd1954 100644
--- a/compiler/rustc_codegen_ssa/src/errors.rs
+++ b/compiler/rustc_codegen_ssa/src/errors.rs
@@ -764,6 +764,14 @@ pub enum InvalidMonomorphization<'tcx> {
         ty: Ty<'tcx>,
     },
 
+    #[diag(codegen_ssa_invalid_monomorphization_basic_integer_or_ptr_type, code = E0511)]
+    BasicIntegerOrPtrType {
+        #[primary_span]
+        span: Span,
+        name: Symbol,
+        ty: Ty<'tcx>,
+    },
+
     #[diag(codegen_ssa_invalid_monomorphization_basic_float_type, code = E0511)]
     BasicFloatType {
         #[primary_span]
diff --git a/compiler/rustc_codegen_ssa/src/mir/intrinsic.rs b/compiler/rustc_codegen_ssa/src/mir/intrinsic.rs
index fc95f62b4a4..3c667b8e882 100644
--- a/compiler/rustc_codegen_ssa/src/mir/intrinsic.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/intrinsic.rs
@@ -92,6 +92,13 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         let invalid_monomorphization_int_type = |ty| {
             bx.tcx().dcx().emit_err(InvalidMonomorphization::BasicIntegerType { span, name, ty });
         };
+        let invalid_monomorphization_int_or_ptr_type = |ty| {
+            bx.tcx().dcx().emit_err(InvalidMonomorphization::BasicIntegerOrPtrType {
+                span,
+                name,
+                ty,
+            });
+        };
 
         let parse_atomic_ordering = |ord: ty::Value<'tcx>| {
             let discr = ord.valtree.unwrap_branch()[0].unwrap_leaf();
@@ -351,7 +358,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             sym::atomic_load => {
                 let ty = fn_args.type_at(0);
                 if !(int_type_width_signed(ty, bx.tcx()).is_some() || ty.is_raw_ptr()) {
-                    invalid_monomorphization_int_type(ty);
+                    invalid_monomorphization_int_or_ptr_type(ty);
                     return Ok(());
                 }
                 let ordering = fn_args.const_at(1).to_value();
@@ -367,7 +374,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             sym::atomic_store => {
                 let ty = fn_args.type_at(0);
                 if !(int_type_width_signed(ty, bx.tcx()).is_some() || ty.is_raw_ptr()) {
-                    invalid_monomorphization_int_type(ty);
+                    invalid_monomorphization_int_or_ptr_type(ty);
                     return Ok(());
                 }
                 let ordering = fn_args.const_at(1).to_value();
@@ -377,10 +384,11 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 bx.atomic_store(val, ptr, parse_atomic_ordering(ordering), size);
                 return Ok(());
             }
+            // These are all AtomicRMW ops
             sym::atomic_cxchg | sym::atomic_cxchgweak => {
                 let ty = fn_args.type_at(0);
                 if !(int_type_width_signed(ty, bx.tcx()).is_some() || ty.is_raw_ptr()) {
-                    invalid_monomorphization_int_type(ty);
+                    invalid_monomorphization_int_or_ptr_type(ty);
                     return Ok(());
                 }
                 let succ_ordering = fn_args.const_at(1).to_value();
@@ -407,7 +415,6 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
 
                 return Ok(());
             }
-            // These are all AtomicRMW ops
             sym::atomic_max | sym::atomic_min => {
                 let atom_op = if name == sym::atomic_max {
                     AtomicRmwBinOp::AtomicMax
@@ -420,7 +427,13 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                     let ordering = fn_args.const_at(1).to_value();
                     let ptr = args[0].immediate();
                     let val = args[1].immediate();
-                    bx.atomic_rmw(atom_op, ptr, val, parse_atomic_ordering(ordering))
+                    bx.atomic_rmw(
+                        atom_op,
+                        ptr,
+                        val,
+                        parse_atomic_ordering(ordering),
+                        /* ret_ptr */ false,
+                    )
                 } else {
                     invalid_monomorphization_int_type(ty);
                     return Ok(());
@@ -438,21 +451,44 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                     let ordering = fn_args.const_at(1).to_value();
                     let ptr = args[0].immediate();
                     let val = args[1].immediate();
-                    bx.atomic_rmw(atom_op, ptr, val, parse_atomic_ordering(ordering))
+                    bx.atomic_rmw(
+                        atom_op,
+                        ptr,
+                        val,
+                        parse_atomic_ordering(ordering),
+                        /* ret_ptr */ false,
+                    )
                 } else {
                     invalid_monomorphization_int_type(ty);
                     return Ok(());
                 }
             }
-            sym::atomic_xchg
-            | sym::atomic_xadd
+            sym::atomic_xchg => {
+                let ty = fn_args.type_at(0);
+                let ordering = fn_args.const_at(1).to_value();
+                if int_type_width_signed(ty, bx.tcx()).is_some() || ty.is_raw_ptr() {
+                    let ptr = args[0].immediate();
+                    let val = args[1].immediate();
+                    let atomic_op = AtomicRmwBinOp::AtomicXchg;
+                    bx.atomic_rmw(
+                        atomic_op,
+                        ptr,
+                        val,
+                        parse_atomic_ordering(ordering),
+                        /* ret_ptr */ ty.is_raw_ptr(),
+                    )
+                } else {
+                    invalid_monomorphization_int_or_ptr_type(ty);
+                    return Ok(());
+                }
+            }
+            sym::atomic_xadd
             | sym::atomic_xsub
             | sym::atomic_and
             | sym::atomic_nand
             | sym::atomic_or
             | sym::atomic_xor => {
                 let atom_op = match name {
-                    sym::atomic_xchg => AtomicRmwBinOp::AtomicXchg,
                     sym::atomic_xadd => AtomicRmwBinOp::AtomicAdd,
                     sym::atomic_xsub => AtomicRmwBinOp::AtomicSub,
                     sym::atomic_and => AtomicRmwBinOp::AtomicAnd,
@@ -462,14 +498,28 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                     _ => unreachable!(),
                 };
 
-                let ty = fn_args.type_at(0);
-                if int_type_width_signed(ty, bx.tcx()).is_some() || ty.is_raw_ptr() {
-                    let ordering = fn_args.const_at(1).to_value();
-                    let ptr = args[0].immediate();
-                    let val = args[1].immediate();
-                    bx.atomic_rmw(atom_op, ptr, val, parse_atomic_ordering(ordering))
+                // The type of the in-memory data.
+                let ty_mem = fn_args.type_at(0);
+                // The type of the 2nd operand, given by-value.
+                let ty_op = fn_args.type_at(1);
+
+                let ordering = fn_args.const_at(2).to_value();
+                // We require either both arguments to have the same integer type, or the first to
+                // be a pointer and the second to be `usize`.
+                if (int_type_width_signed(ty_mem, bx.tcx()).is_some() && ty_op == ty_mem)
+                    || (ty_mem.is_raw_ptr() && ty_op == bx.tcx().types.usize)
+                {
+                    let ptr = args[0].immediate(); // of type "pointer to `ty_mem`"
+                    let val = args[1].immediate(); // of type `ty_op`
+                    bx.atomic_rmw(
+                        atom_op,
+                        ptr,
+                        val,
+                        parse_atomic_ordering(ordering),
+                        /* ret_ptr */ ty_mem.is_raw_ptr(),
+                    )
                 } else {
-                    invalid_monomorphization_int_type(ty);
+                    invalid_monomorphization_int_or_ptr_type(ty_mem);
                     return Ok(());
                 }
             }
diff --git a/compiler/rustc_codegen_ssa/src/mir/mod.rs b/compiler/rustc_codegen_ssa/src/mir/mod.rs
index 50d0f910744..06873313e2e 100644
--- a/compiler/rustc_codegen_ssa/src/mir/mod.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/mod.rs
@@ -296,10 +296,6 @@ pub fn codegen_mir<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
     // Apply debuginfo to the newly allocated locals.
     fx.debug_introduce_locals(&mut start_bx, consts_debug_info.unwrap_or_default());
 
-    // If the backend supports coverage, and coverage is enabled for this function,
-    // do any necessary start-of-function codegen (e.g. locals for MC/DC bitmaps).
-    start_bx.init_coverage(instance);
-
     // The builders will be created separately for each basic block at `codegen_block`.
     // So drop the builder of `start_llbb` to avoid having two at the same time.
     drop(start_bx);
diff --git a/compiler/rustc_codegen_ssa/src/mir/operand.rs b/compiler/rustc_codegen_ssa/src/mir/operand.rs
index 5459f95c186..d851c332980 100644
--- a/compiler/rustc_codegen_ssa/src/mir/operand.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/operand.rs
@@ -498,6 +498,35 @@ impl<'a, 'tcx, V: CodegenObject> OperandRef<'tcx, V> {
                         bx.cx().const_uint(cast_to, niche_variants.start().as_u32() as u64);
                     (is_niche, tagged_discr, 0)
                 } else {
+                    // Thanks to parameter attributes and load metadata, LLVM already knows
+                    // the general valid range of the tag. It's possible, though, for there
+                    // to be an impossible value *in the middle*, which those ranges don't
+                    // communicate, so it's worth an `assume` to let the optimizer know.
+                    // Most importantly, this means when optimizing a variant test like
+                    // `SELECT(is_niche, complex, CONST) == CONST` it's ok to simplify that
+                    // to `!is_niche` because the `complex` part can't possibly match.
+                    //
+                    // This was previously asserted on `tagged_discr` below, where the
+                    // impossible value is more obvious, but that caused an intermediate
+                    // value to become multi-use and thus not optimize, so instead this
+                    // assumes on the original input which is always multi-use. See
+                    // <https://github.com/llvm/llvm-project/issues/134024#issuecomment-3131782555>
+                    //
+                    // FIXME: If we ever get range assume operand bundles in LLVM (so we
+                    // don't need the `icmp`s in the instruction stream any more), it
+                    // might be worth moving this back to being on the switch argument
+                    // where it's more obviously applicable.
+                    if niche_variants.contains(&untagged_variant)
+                        && bx.cx().sess().opts.optimize != OptLevel::No
+                    {
+                        let impossible = niche_start
+                            .wrapping_add(u128::from(untagged_variant.as_u32()))
+                            .wrapping_sub(u128::from(niche_variants.start().as_u32()));
+                        let impossible = bx.cx().const_uint_big(tag_llty, impossible);
+                        let ne = bx.icmp(IntPredicate::IntNE, tag, impossible);
+                        bx.assume(ne);
+                    }
+
                     // With multiple niched variants we'll have to actually compute
                     // the variant index from the stored tag.
                     //
@@ -588,20 +617,6 @@ impl<'a, 'tcx, V: CodegenObject> OperandRef<'tcx, V> {
                 let untagged_variant_const =
                     bx.cx().const_uint(cast_to, u64::from(untagged_variant.as_u32()));
 
-                // Thanks to parameter attributes and load metadata, LLVM already knows
-                // the general valid range of the tag. It's possible, though, for there
-                // to be an impossible value *in the middle*, which those ranges don't
-                // communicate, so it's worth an `assume` to let the optimizer know.
-                // Most importantly, this means when optimizing a variant test like
-                // `SELECT(is_niche, complex, CONST) == CONST` it's ok to simplify that
-                // to `!is_niche` because the `complex` part can't possibly match.
-                if niche_variants.contains(&untagged_variant)
-                    && bx.cx().sess().opts.optimize != OptLevel::No
-                {
-                    let ne = bx.icmp(IntPredicate::IntNE, tagged_discr, untagged_variant_const);
-                    bx.assume(ne);
-                }
-
                 let discr = bx.select(is_niche, tagged_discr, untagged_variant_const);
 
                 // In principle we could insert assumes on the possible range of `discr`, but
diff --git a/compiler/rustc_codegen_ssa/src/target_features.rs b/compiler/rustc_codegen_ssa/src/target_features.rs
index d984156c674..7e4341a8236 100644
--- a/compiler/rustc_codegen_ssa/src/target_features.rs
+++ b/compiler/rustc_codegen_ssa/src/target_features.rs
@@ -197,7 +197,10 @@ fn parse_rust_feature_flag<'a>(
 /// 2nd component of the return value, respectively).
 ///
 /// `target_base_has_feature` should check whether the given feature (a Rust feature name!) is
-/// enabled in the "base" target machine, i.e., without applying `-Ctarget-feature`.
+/// enabled in the "base" target machine, i.e., without applying `-Ctarget-feature`. Note that LLVM
+/// may consider features to be implied that we do not and vice-versa. We want `cfg` to be entirely
+/// consistent with Rust feature implications, and thus only consult LLVM to expand the target CPU
+/// to target features.
 ///
 /// We do not have to worry about RUSTC_SPECIFIC_FEATURES here, those are handled elsewhere.
 pub fn cfg_target_feature(
@@ -211,7 +214,15 @@ pub fn cfg_target_feature(
         .rust_target_features()
         .iter()
         .filter(|(feature, _, _)| target_base_has_feature(feature))
-        .map(|(feature, _, _)| Symbol::intern(feature))
+        .flat_map(|(base_feature, _, _)| {
+            // Expand the direct base feature into all transitively-implied features. Note that we
+            // cannot simply use the `implied` field of the tuple since that only contains
+            // directly-implied features.
+            //
+            // Iteration order is irrelevant because we're collecting into an `UnordSet`.
+            #[allow(rustc::potential_query_instability)]
+            sess.target.implied_target_features(base_feature).into_iter().map(|f| Symbol::intern(f))
+        })
         .collect();
 
     // Add enabled and remove disabled features.
diff --git a/compiler/rustc_codegen_ssa/src/traits/builder.rs b/compiler/rustc_codegen_ssa/src/traits/builder.rs
index 4b18146863b..f417d1a7bf7 100644
--- a/compiler/rustc_codegen_ssa/src/traits/builder.rs
+++ b/compiler/rustc_codegen_ssa/src/traits/builder.rs
@@ -548,12 +548,15 @@ pub trait BuilderMethods<'a, 'tcx>:
         failure_order: AtomicOrdering,
         weak: bool,
     ) -> (Self::Value, Self::Value);
+    /// `ret_ptr` indicates whether the return type (which is also the type `dst` points to)
+    /// is a pointer or the same type as `src`.
     fn atomic_rmw(
         &mut self,
         op: AtomicRmwBinOp,
         dst: Self::Value,
         src: Self::Value,
         order: AtomicOrdering,
+        ret_ptr: bool,
     ) -> Self::Value;
     fn atomic_fence(&mut self, order: AtomicOrdering, scope: SynchronizationScope);
     fn set_invariant_load(&mut self, load: Self::Value);
diff --git a/compiler/rustc_codegen_ssa/src/traits/coverageinfo.rs b/compiler/rustc_codegen_ssa/src/traits/coverageinfo.rs
index 0b513dac503..31482a53b6d 100644
--- a/compiler/rustc_codegen_ssa/src/traits/coverageinfo.rs
+++ b/compiler/rustc_codegen_ssa/src/traits/coverageinfo.rs
@@ -2,11 +2,6 @@ use rustc_middle::mir::coverage::CoverageKind;
 use rustc_middle::ty::Instance;
 
 pub trait CoverageInfoBuilderMethods<'tcx> {
-    /// Performs any start-of-function codegen needed for coverage instrumentation.
-    ///
-    /// Can be a no-op in backends that don't support coverage instrumentation.
-    fn init_coverage(&mut self, _instance: Instance<'tcx>) {}
-
     /// Handle the MIR coverage info in a backend-specific way.
     ///
     /// This can potentially be a no-op in backends that don't support