Rollup of 6 pull requests

compiler/rustc_codegen_llvm/src/attributes.rs

@@ -232,11 +232,6 @@ fn probestack_attr<'ll>(cx: &CodegenCx<'ll, '_>) -> Option<&'ll Attribute> {
         return None;
     }
 
-    // probestack doesn't play nice either with gcov profiling.
-    if cx.sess().opts.unstable_opts.profile {
-        return None;
-    }
-
     let attr_value = match cx.sess().target.stack_probes {
         StackProbeType::None => return None,
         // Request LLVM to generate the probes inline. If the given LLVM version does not support

compiler/rustc_codegen_llvm/src/back/write.rs

@@ -591,7 +591,6 @@ pub(crate) unsafe fn llvm_optimize(
             pgo_use_path.as_ref().map_or(std::ptr::null(), |s| s.as_ptr()),
             config.instrument_coverage,
             instr_profile_output_path.as_ref().map_or(std::ptr::null(), |s| s.as_ptr()),
-            config.instrument_gcov,
             pgo_sample_use_path.as_ref().map_or(std::ptr::null(), |s| s.as_ptr()),
             config.debug_info_for_profiling,
             llvm_selfprofiler,

compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs

@@ -7,7 +7,6 @@ use std::{iter, ptr};
 use libc::{c_char, c_longlong, c_uint};
 use rustc_codegen_ssa::debuginfo::type_names::{VTableNameKind, cpp_like_debuginfo};
 use rustc_codegen_ssa::traits::*;
-use rustc_fs_util::path_to_c_string;
 use rustc_hir::def::{CtorKind, DefKind};
 use rustc_hir::def_id::{DefId, LOCAL_CRATE};
 use rustc_middle::bug;
@@ -979,33 +978,8 @@ pub(crate) fn build_compile_unit_di_node<'ll, 'tcx>(
             debug_name_table_kind,
         );
 
-        if tcx.sess.opts.unstable_opts.profile {
-            let default_gcda_path = &output_filenames.with_extension("gcda");
-            let gcda_path =
-                tcx.sess.opts.unstable_opts.profile_emit.as_ref().unwrap_or(default_gcda_path);
-
-            let gcov_cu_info = [
-                path_to_mdstring(debug_context.llcontext, &output_filenames.with_extension("gcno")),
-                path_to_mdstring(debug_context.llcontext, gcda_path),
-                unit_metadata,
-            ];
-            let gcov_metadata = llvm::LLVMMDNodeInContext2(
-                debug_context.llcontext,
-                gcov_cu_info.as_ptr(),
-                gcov_cu_info.len(),
-            );
-            let val = llvm::LLVMMetadataAsValue(debug_context.llcontext, gcov_metadata);
-
-            llvm::LLVMAddNamedMetadataOperand(debug_context.llmod, c"llvm.gcov".as_ptr(), val);
-        }
-
         return unit_metadata;
     };
-
-    fn path_to_mdstring<'ll>(llcx: &'ll llvm::Context, path: &Path) -> &'ll llvm::Metadata {
-        let path_str = path_to_c_string(path);
-        unsafe { llvm::LLVMMDStringInContext2(llcx, path_str.as_ptr(), path_str.as_bytes().len()) }
-    }
 }
 
 /// Creates a `DW_TAG_member` entry inside the DIE represented by the given `type_di_node`.

compiler/rustc_codegen_llvm/src/debuginfo/mod.rs

@@ -55,7 +55,6 @@ const DW_TAG_arg_variable: c_uint = 0x101;
 
 /// A context object for maintaining all state needed by the debuginfo module.
 pub(crate) struct CodegenUnitDebugContext<'ll, 'tcx> {
-    llcontext: &'ll llvm::Context,
     llmod: &'ll llvm::Module,
     builder: &'ll mut DIBuilder<'ll>,
     created_files: RefCell<UnordMap<Option<(StableSourceFileId, SourceFileHash)>, &'ll DIFile>>,
@@ -78,9 +77,7 @@ impl<'ll, 'tcx> CodegenUnitDebugContext<'ll, 'tcx> {
         debug!("CodegenUnitDebugContext::new");
         let builder = unsafe { llvm::LLVMRustDIBuilderCreate(llmod) };
         // DIBuilder inherits context from the module, so we'd better use the same one
-        let llcontext = unsafe { llvm::LLVMGetModuleContext(llmod) };
         CodegenUnitDebugContext {
-            llcontext,
             llmod,
             builder,
             created_files: Default::default(),

compiler/rustc_codegen_llvm/src/llvm/ffi.rs

@@ -2269,7 +2269,6 @@ unsafe extern "C" {
         PGOUsePath: *const c_char,
         InstrumentCoverage: bool,
         InstrProfileOutput: *const c_char,
-        InstrumentGCOV: bool,
         PGOSampleUsePath: *const c_char,
         DebugInfoForProfiling: bool,
         llvm_selfprofiler: *mut c_void,

compiler/rustc_codegen_ssa/src/back/write.rs

@@ -90,7 +90,6 @@ pub struct ModuleConfig {
     pub pgo_sample_use: Option<PathBuf>,
     pub debug_info_for_profiling: bool,
     pub instrument_coverage: bool,
-    pub instrument_gcov: bool,
 
     pub sanitizer: SanitizerSet,
     pub sanitizer_recover: SanitizerSet,
@@ -123,12 +122,7 @@ pub struct ModuleConfig {
 }
 
 impl ModuleConfig {
-    fn new(
-        kind: ModuleKind,
-        tcx: TyCtxt<'_>,
-        no_builtins: bool,
-        is_compiler_builtins: bool,
-    ) -> ModuleConfig {
+    fn new(kind: ModuleKind, tcx: TyCtxt<'_>, no_builtins: bool) -> ModuleConfig {
         // If it's a regular module, use `$regular`, otherwise use `$other`.
         // `$regular` and `$other` are evaluated lazily.
         macro_rules! if_regular {
@@ -189,13 +183,6 @@ impl ModuleConfig {
             pgo_sample_use: if_regular!(sess.opts.unstable_opts.profile_sample_use.clone(), None),
             debug_info_for_profiling: sess.opts.unstable_opts.debug_info_for_profiling,
             instrument_coverage: if_regular!(sess.instrument_coverage(), false),
-            instrument_gcov: if_regular!(
-                // compiler_builtins overrides the codegen-units settings,
-                // which is incompatible with -Zprofile which requires that
-                // only a single codegen unit is used per crate.
-                sess.opts.unstable_opts.profile && !is_compiler_builtins,
-                false
-            ),
 
             sanitizer: if_regular!(sess.opts.unstable_opts.sanitizer, SanitizerSet::empty()),
             sanitizer_dataflow_abilist: if_regular!(
@@ -473,16 +460,12 @@ pub(crate) fn start_async_codegen<B: ExtraBackendMethods>(
 
     let crate_attrs = tcx.hir().attrs(rustc_hir::CRATE_HIR_ID);
     let no_builtins = attr::contains_name(crate_attrs, sym::no_builtins);
-    let is_compiler_builtins = attr::contains_name(crate_attrs, sym::compiler_builtins);
 
     let crate_info = CrateInfo::new(tcx, target_cpu);
 
-    let regular_config =
-        ModuleConfig::new(ModuleKind::Regular, tcx, no_builtins, is_compiler_builtins);
-    let metadata_config =
-        ModuleConfig::new(ModuleKind::Metadata, tcx, no_builtins, is_compiler_builtins);
-    let allocator_config =
-        ModuleConfig::new(ModuleKind::Allocator, tcx, no_builtins, is_compiler_builtins);
+    let regular_config = ModuleConfig::new(ModuleKind::Regular, tcx, no_builtins);
+    let metadata_config = ModuleConfig::new(ModuleKind::Metadata, tcx, no_builtins);
+    let allocator_config = ModuleConfig::new(ModuleKind::Allocator, tcx, no_builtins);
 
     let (shared_emitter, shared_emitter_main) = SharedEmitter::new();
     let (codegen_worker_send, codegen_worker_receive) = channel();

compiler/rustc_hir_typeck/src/errors.rs

@@ -169,19 +169,34 @@ pub(crate) struct MissingParenthesesInRange {
 pub(crate) enum NeverTypeFallbackFlowingIntoUnsafe {
     #[help]
     #[diag(hir_typeck_never_type_fallback_flowing_into_unsafe_call)]
-    Call,
+    Call {
+        #[subdiagnostic]
+        sugg: SuggestAnnotations,
+    },
     #[help]
     #[diag(hir_typeck_never_type_fallback_flowing_into_unsafe_method)]
-    Method,
+    Method {
+        #[subdiagnostic]
+        sugg: SuggestAnnotations,
+    },
     #[help]
     #[diag(hir_typeck_never_type_fallback_flowing_into_unsafe_path)]
-    Path,
+    Path {
+        #[subdiagnostic]
+        sugg: SuggestAnnotations,
+    },
     #[help]
     #[diag(hir_typeck_never_type_fallback_flowing_into_unsafe_union_field)]
-    UnionField,
+    UnionField {
+        #[subdiagnostic]
+        sugg: SuggestAnnotations,
+    },
     #[help]
     #[diag(hir_typeck_never_type_fallback_flowing_into_unsafe_deref)]
-    Deref,
+    Deref {
+        #[subdiagnostic]
+        sugg: SuggestAnnotations,
+    },
 }
 
 #[derive(LintDiagnostic)]
@@ -191,6 +206,64 @@ pub(crate) struct DependencyOnUnitNeverTypeFallback<'tcx> {
     #[note]
     pub obligation_span: Span,
     pub obligation: ty::Predicate<'tcx>,
+    #[subdiagnostic]
+    pub sugg: SuggestAnnotations,
+}
+
+#[derive(Clone)]
+pub(crate) enum SuggestAnnotation {
+    Unit(Span),
+    Path(Span),
+    Local(Span),
+    Turbo(Span, usize, usize),
+}
+
+#[derive(Clone)]
+pub(crate) struct SuggestAnnotations {
+    pub suggestions: Vec<SuggestAnnotation>,
+}
+impl Subdiagnostic for SuggestAnnotations {
+    fn add_to_diag_with<G: EmissionGuarantee, F: SubdiagMessageOp<G>>(
+        self,
+        diag: &mut Diag<'_, G>,
+        _: &F,
+    ) {
+        if self.suggestions.is_empty() {
+            return;
+        }
+
+        let mut suggestions = vec![];
+        for suggestion in self.suggestions {
+            match suggestion {
+                SuggestAnnotation::Unit(span) => {
+                    suggestions.push((span, "()".to_string()));
+                }
+                SuggestAnnotation::Path(span) => {
+                    suggestions.push((span.shrink_to_lo(), "<() as ".to_string()));
+                    suggestions.push((span.shrink_to_hi(), ">".to_string()));
+                }
+                SuggestAnnotation::Local(span) => {
+                    suggestions.push((span, ": ()".to_string()));
+                }
+                SuggestAnnotation::Turbo(span, n_args, idx) => suggestions.push((
+                    span,
+                    format!(
+                        "::<{}>",
+                        (0..n_args)
+                            .map(|i| if i == idx { "()" } else { "_" })
+                            .collect::<Vec<_>>()
+                            .join(", "),
+                    ),
+                )),
+            }
+        }
+
+        diag.multipart_suggestion_verbose(
+            "use `()` annotations to avoid fallback changes",
+            suggestions,
+            Applicability::MachineApplicable,
+        );
+    }
 }
 
 #[derive(Subdiagnostic)]