Auto merge of #145062 - tgross35:rollup-1wm2fv2, r=tgross35

Rollup of 6 pull requests

Successful merges:

 - #144400 (`tests/ui/issues/`: The Issues Strike Back [3/N])
 - #144678 (Make no_mangle on foreign items explicit instead of implicit)
 - #145045 (doc(library): Fix Markdown in `Iterator::by_ref`)
 - #145046 (Fix doc comment of File::try_lock and File::try_lock_shared)
 - #145047 (move `type_check` out of `compute_regions`)
 - #145053 (Add a lot of NLL `known-bug` tests)

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

compiler/rustc_borrowck/src/lib.rs

@@ -19,6 +19,7 @@ use std::borrow::Cow;
 use std::cell::{OnceCell, RefCell};
 use std::marker::PhantomData;
 use std::ops::{ControlFlow, Deref};
+use std::rc::Rc;
 
 use borrow_set::LocalsStateAtExit;
 use root_cx::BorrowCheckRootCtxt;
@@ -44,6 +45,7 @@ use rustc_mir_dataflow::impls::{EverInitializedPlaces, MaybeUninitializedPlaces}
 use rustc_mir_dataflow::move_paths::{
     InitIndex, InitLocation, LookupResult, MoveData, MovePathIndex,
 };
+use rustc_mir_dataflow::points::DenseLocationMap;
 use rustc_mir_dataflow::{Analysis, Results, ResultsVisitor, visit_results};
 use rustc_session::lint::builtin::{TAIL_EXPR_DROP_ORDER, UNUSED_MUT};
 use rustc_span::{ErrorGuaranteed, Span, Symbol};
@@ -60,11 +62,14 @@ use crate::path_utils::*;
 use crate::place_ext::PlaceExt;
 use crate::places_conflict::{PlaceConflictBias, places_conflict};
 use crate::polonius::PoloniusDiagnosticsContext;
-use crate::polonius::legacy::{PoloniusLocationTable, PoloniusOutput};
+use crate::polonius::legacy::{
+    PoloniusFacts, PoloniusFactsExt, PoloniusLocationTable, PoloniusOutput,
+};
 use crate::prefixes::PrefixSet;
 use crate::region_infer::RegionInferenceContext;
 use crate::renumber::RegionCtxt;
 use crate::session_diagnostics::VarNeedNotMut;
+use crate::type_check::MirTypeckResults;
 
 mod borrow_set;
 mod borrowck_errors;
@@ -321,7 +326,34 @@ fn do_mir_borrowck<'tcx>(
     let locals_are_invalidated_at_exit = tcx.hir_body_owner_kind(def).is_fn_or_closure();
     let borrow_set = BorrowSet::build(tcx, body, locals_are_invalidated_at_exit, &move_data);
 
-    // Compute non-lexical lifetimes.
+    let location_map = Rc::new(DenseLocationMap::new(body));
+
+    let polonius_input = root_cx.consumer.as_ref().map_or(false, |c| c.polonius_input())
+        || infcx.tcx.sess.opts.unstable_opts.polonius.is_legacy_enabled();
+    let mut polonius_facts =
+        (polonius_input || PoloniusFacts::enabled(infcx.tcx)).then_some(PoloniusFacts::default());
+
+    // Run the MIR type-checker.
+    let MirTypeckResults {
+        constraints,
+        universal_region_relations,
+        opaque_type_values,
+        polonius_context,
+    } = type_check::type_check(
+        root_cx,
+        &infcx,
+        body,
+        &promoted,
+        universal_regions,
+        &location_table,
+        &borrow_set,
+        &mut polonius_facts,
+        &move_data,
+        Rc::clone(&location_map),
+    );
+
+    // Compute non-lexical lifetimes using the constraints computed
+    // by typechecking the MIR body.
     let nll::NllOutput {
         regioncx,
         polonius_input,
@@ -332,14 +364,19 @@ fn do_mir_borrowck<'tcx>(
     } = nll::compute_regions(
         root_cx,
         &infcx,
-        universal_regions,
         body,
-        &promoted,
         &location_table,
         &move_data,
         &borrow_set,
+        location_map,
+        universal_region_relations,
+        constraints,
+        polonius_facts,
+        polonius_context,
     );
 
+    regioncx.infer_opaque_types(root_cx, &infcx, opaque_type_values);
+
     // Dump MIR results into a file, if that is enabled. This lets us
     // write unit-tests, as well as helping with debugging.
     nll::dump_nll_mir(&infcx, body, &regioncx, &opt_closure_req, &borrow_set);

compiler/rustc_borrowck/src/nll.rs

@@ -5,7 +5,8 @@ use std::path::PathBuf;
 use std::rc::Rc;
 use std::str::FromStr;
 
-use polonius_engine::{Algorithm, Output};
+use polonius_engine::{Algorithm, AllFacts, Output};
+use rustc_data_structures::frozen::Frozen;
 use rustc_index::IndexSlice;
 use rustc_middle::mir::pretty::{PrettyPrintMirOptions, dump_mir_with_options};
 use rustc_middle::mir::{Body, PassWhere, Promoted, create_dump_file, dump_enabled, dump_mir};
@@ -18,14 +19,16 @@ use rustc_span::sym;
 use tracing::{debug, instrument};
 
 use crate::borrow_set::BorrowSet;
+use crate::consumers::RustcFacts;
 use crate::diagnostics::RegionErrors;
 use crate::handle_placeholders::compute_sccs_applying_placeholder_outlives_constraints;
-use crate::polonius::PoloniusDiagnosticsContext;
 use crate::polonius::legacy::{
     PoloniusFacts, PoloniusFactsExt, PoloniusLocationTable, PoloniusOutput,
 };
+use crate::polonius::{PoloniusContext, PoloniusDiagnosticsContext};
 use crate::region_infer::RegionInferenceContext;
-use crate::type_check::{self, MirTypeckResults};
+use crate::type_check::MirTypeckRegionConstraints;
+use crate::type_check::free_region_relations::UniversalRegionRelations;
 use crate::universal_regions::UniversalRegions;
 use crate::{
     BorrowCheckRootCtxt, BorrowckInferCtxt, ClosureOutlivesSubject, ClosureRegionRequirements,
@@ -76,41 +79,18 @@ pub(crate) fn replace_regions_in_mir<'tcx>(
 pub(crate) fn compute_regions<'tcx>(
     root_cx: &mut BorrowCheckRootCtxt<'tcx>,
     infcx: &BorrowckInferCtxt<'tcx>,
-    universal_regions: UniversalRegions<'tcx>,
     body: &Body<'tcx>,
-    promoted: &IndexSlice<Promoted, Body<'tcx>>,
     location_table: &PoloniusLocationTable,
     move_data: &MoveData<'tcx>,
     borrow_set: &BorrowSet<'tcx>,
+    location_map: Rc<DenseLocationMap>,
+    universal_region_relations: Frozen<UniversalRegionRelations<'tcx>>,
+    constraints: MirTypeckRegionConstraints<'tcx>,
+    mut polonius_facts: Option<AllFacts<RustcFacts>>,
+    polonius_context: Option<PoloniusContext>,
 ) -> NllOutput<'tcx> {
-    let is_polonius_legacy_enabled = infcx.tcx.sess.opts.unstable_opts.polonius.is_legacy_enabled();
-    let polonius_input = root_cx.consumer.as_ref().map_or(false, |c| c.polonius_input())
-        || is_polonius_legacy_enabled;
     let polonius_output = root_cx.consumer.as_ref().map_or(false, |c| c.polonius_output())
-        || is_polonius_legacy_enabled;
-    let mut polonius_facts =
-        (polonius_input || PoloniusFacts::enabled(infcx.tcx)).then_some(PoloniusFacts::default());
-
-    let location_map = Rc::new(DenseLocationMap::new(body));
-
-    // Run the MIR type-checker.
-    let MirTypeckResults {
-        constraints,
-        universal_region_relations,
-        opaque_type_values,
-        polonius_context,
-    } = type_check::type_check(
-        root_cx,
-        infcx,
-        body,
-        promoted,
-        universal_regions,
-        location_table,
-        borrow_set,
-        &mut polonius_facts,
-        move_data,
-        Rc::clone(&location_map),
-    );
+        || infcx.tcx.sess.opts.unstable_opts.polonius.is_legacy_enabled();
 
     let lowered_constraints = compute_sccs_applying_placeholder_outlives_constraints(
         constraints,
@@ -173,8 +153,6 @@ pub(crate) fn compute_regions<'tcx>(
         infcx.set_tainted_by_errors(guar);
     }
 
-    regioncx.infer_opaque_types(root_cx, infcx, opaque_type_values);
-
     NllOutput {
         regioncx,
         polonius_input: polonius_facts.map(Box::new),

compiler/rustc_codegen_ssa/src/back/symbol_export.rs

@@ -586,7 +586,7 @@ fn symbol_export_level(tcx: TyCtxt<'_>, sym_def_id: DefId) -> SymbolExportLevel
     // core/std/allocators/etc. For example symbols used to hook up allocation
     // are not considered for export
     let codegen_fn_attrs = tcx.codegen_fn_attrs(sym_def_id);
-    let is_extern = codegen_fn_attrs.contains_extern_indicator();
+    let is_extern = codegen_fn_attrs.contains_extern_indicator(tcx, sym_def_id);
     let std_internal =
         codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL);
 

compiler/rustc_codegen_ssa/src/codegen_attrs.rs

@@ -443,6 +443,35 @@ fn apply_overrides(tcx: TyCtxt<'_>, did: LocalDefId, codegen_fn_attrs: &mut Code
     if tcx.should_inherit_track_caller(did) {
         codegen_fn_attrs.flags |= CodegenFnAttrFlags::TRACK_CALLER;
     }
+
+    // Foreign items by default use no mangling for their symbol name.
+    if tcx.is_foreign_item(did) {
+        // There's a few exceptions to this rule though:
+        if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL) {
+            // * `#[rustc_std_internal_symbol]` mangles the symbol name in a special way
+            //   both for exports and imports through foreign items. This is handled further,
+            //   during symbol mangling logic.
+        } else if codegen_fn_attrs.link_name.is_some() {
+            // * This can be overridden with the `#[link_name]` attribute
+        } else if tcx.sess.target.is_like_wasm
+            && tcx.wasm_import_module_map(LOCAL_CRATE).contains_key(&did.into())
+        {
+            // * On the wasm32 targets there is a bug (or feature) in LLD [1] where the
+            //   same-named symbol when imported from different wasm modules will get
+            //   hooked up incorrectly. As a result foreign symbols, on the wasm target,
+            //   with a wasm import module, get mangled. Additionally our codegen will
+            //   deduplicate symbols based purely on the symbol name, but for wasm this
+            //   isn't quite right because the same-named symbol on wasm can come from
+            //   different modules. For these reasons if `#[link(wasm_import_module)]`
+            //   is present we mangle everything on wasm because the demangled form will
+            //   show up in the `wasm-import-name` custom attribute in LLVM IR.
+            //
+            // [1]: https://bugs.llvm.org/show_bug.cgi?id=44316
+        } else {
+            // if none of the exceptions apply; apply no_mangle
+            codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_MANGLE;
+        }
+    }
 }
 
 fn check_result(

compiler/rustc_middle/src/middle/codegen_fn_attrs.rs

@@ -3,6 +3,7 @@ use std::borrow::Cow;
 use rustc_abi::Align;
 use rustc_ast::expand::autodiff_attrs::AutoDiffAttrs;
 use rustc_hir::attrs::{InlineAttr, InstructionSetAttr, OptimizeAttr};
+use rustc_hir::def_id::DefId;
 use rustc_macros::{HashStable, TyDecodable, TyEncodable};
 use rustc_span::Symbol;
 use rustc_target::spec::SanitizerSet;
@@ -193,7 +194,11 @@ impl CodegenFnAttrs {
     /// * `#[linkage]` is present
     ///
     /// Keep this in sync with the logic for the unused_attributes for `#[inline]` lint.
-    pub fn contains_extern_indicator(&self) -> bool {
+    pub fn contains_extern_indicator(&self, tcx: TyCtxt<'_>, did: DefId) -> bool {
+        if tcx.is_foreign_item(did) {
+            return false;
+        }
+
         self.flags.contains(CodegenFnAttrFlags::NO_MANGLE)
             || self.flags.contains(CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL)
             || self.export_name.is_some()

compiler/rustc_middle/src/mir/mono.rs

@@ -151,7 +151,7 @@ impl<'tcx> MonoItem<'tcx> {
         // instantiation:
         // We emit an unused_attributes lint for this case, which should be kept in sync if possible.
         let codegen_fn_attrs = tcx.codegen_instance_attrs(instance.def);
-        if codegen_fn_attrs.contains_extern_indicator()
+        if codegen_fn_attrs.contains_extern_indicator(tcx, instance.def.def_id())
             || codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::NAKED)
         {
             return InstantiationMode::GloballyShared { may_conflict: false };

compiler/rustc_mir_transform/src/cross_crate_inline.rs

@@ -18,7 +18,7 @@ fn cross_crate_inlinable(tcx: TyCtxt<'_>, def_id: LocalDefId) -> bool {
     let codegen_fn_attrs = tcx.codegen_fn_attrs(def_id);
     // If this has an extern indicator, then this function is globally shared and thus will not
     // generate cgu-internal copies which would make it cross-crate inlinable.
-    if codegen_fn_attrs.contains_extern_indicator() {
+    if codegen_fn_attrs.contains_extern_indicator(tcx, def_id.into()) {
         return false;
     }
 

compiler/rustc_passes/src/check_attr.rs

@@ -561,7 +561,24 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
         match target {
             Target::Fn
             | Target::Closure
-            | Target::Method(MethodKind::Trait { body: true } | MethodKind::Inherent) => {}
+            | Target::Method(MethodKind::Trait { body: true } | MethodKind::Inherent) => {
+                // `#[inline]` is ignored if the symbol must be codegened upstream because it's exported.
+                if let Some(did) = hir_id.as_owner()
+                    && self.tcx.def_kind(did).has_codegen_attrs()
+                    && kind != &InlineAttr::Never
+                {
+                    let attrs = self.tcx.codegen_fn_attrs(did);
+                    // Not checking naked as `#[inline]` is forbidden for naked functions anyways.
+                    if attrs.contains_extern_indicator(self.tcx, did.into()) {
+                        self.tcx.emit_node_span_lint(
+                            UNUSED_ATTRIBUTES,
+                            hir_id,
+                            attr_span,
+                            errors::InlineIgnoredForExported {},
+                        );
+                    }
+                }
+            }
             Target::Method(MethodKind::Trait { body: false }) | Target::ForeignFn => {
                 self.tcx.emit_node_span_lint(
                     UNUSED_ATTRIBUTES,
@@ -588,23 +605,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                 self.dcx().emit_err(errors::InlineNotFnOrClosure { attr_span, defn_span });
             }
         }
-
-        // `#[inline]` is ignored if the symbol must be codegened upstream because it's exported.
-        if let Some(did) = hir_id.as_owner()
-            && self.tcx.def_kind(did).has_codegen_attrs()
-            && kind != &InlineAttr::Never
-        {
-            let attrs = self.tcx.codegen_fn_attrs(did);
-            // Not checking naked as `#[inline]` is forbidden for naked functions anyways.
-            if attrs.contains_extern_indicator() {
-                self.tcx.emit_node_span_lint(
-                    UNUSED_ATTRIBUTES,
-                    hir_id,
-                    attr_span,
-                    errors::InlineIgnoredForExported {},
-                );
-            }
-        }
     }
 
     /// Checks that `#[coverage(..)]` is applied to a function/closure/method,

compiler/rustc_passes/src/dead.rs

@@ -701,7 +701,7 @@ fn has_allow_dead_code_or_lang_attr(
 
             // #[used], #[no_mangle], #[export_name], etc also keeps the item alive
             // forcefully, e.g., for placing it in a specific section.
-            cg_attrs.contains_extern_indicator()
+            cg_attrs.contains_extern_indicator(tcx, def_id.into())
                 || cg_attrs.flags.contains(CodegenFnAttrFlags::USED_COMPILER)
                 || cg_attrs.flags.contains(CodegenFnAttrFlags::USED_LINKER)
         }

compiler/rustc_passes/src/reachable.rs

@@ -183,7 +183,7 @@ impl<'tcx> ReachableContext<'tcx> {
             } else {
                 CodegenFnAttrs::EMPTY
             };
-            let is_extern = codegen_attrs.contains_extern_indicator();
+            let is_extern = codegen_attrs.contains_extern_indicator(self.tcx, search_item.into());
             if is_extern {
                 self.reachable_symbols.insert(search_item);
             }
@@ -423,8 +423,9 @@ fn has_custom_linkage(tcx: TyCtxt<'_>, def_id: LocalDefId) -> bool {
     if !tcx.def_kind(def_id).has_codegen_attrs() {
         return false;
     }
+
     let codegen_attrs = tcx.codegen_fn_attrs(def_id);
-    codegen_attrs.contains_extern_indicator()
+    codegen_attrs.contains_extern_indicator(tcx, def_id.into())
         // FIXME(nbdd0121): `#[used]` are marked as reachable here so it's picked up by
         // `linked_symbols` in cg_ssa. They won't be exported in binary or cdylib due to their
         // `SymbolExportLevel::Rust` export level but may end up being exported in dylibs.