Auto merge of rust-lang#121345 - Nilstrieb:rollup-reb0xge, r=Nilstrieb

Rollup of 8 pull requests

Successful merges:

 - rust-lang#121167 (resolve: Scale back unloading of speculatively loaded crates)
 - rust-lang#121196 (Always inline check in `assert_unsafe_precondition` with cfg(debug_assertions))
 - rust-lang#121241 (Implement `NonZero` traits generically.)
 - rust-lang#121278 (Remove the "codegen" profile from bootstrap)
 - rust-lang#121286 (Rename `ConstPropLint` to `KnownPanicsLint`)
 - rust-lang#121291 (target: Revert default to the medium code model on LoongArch targets)
 - rust-lang#121302 (Remove `RefMutL` hack in `proc_macro::bridge`)
 - rust-lang#121318 (Trigger `unsafe_code` lint on invocations of `global_asm`)

Failed merges:

 - rust-lang#121206 (Top level error handling)

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

Author: bors

compiler/rustc_builtin_macros/src/asm.rs

@@ -773,7 +773,7 @@ pub(super) fn expand_global_asm<'cx>(
                         kind: ast::VisibilityKind::Inherited,
                         tokens: None,
                     },
-                    span: ecx.with_def_site_ctxt(sp),
+                    span: sp,
                     tokens: None,
                 })])
             } else {

compiler/rustc_lint/messages.ftl

@@ -72,8 +72,11 @@ lint_builtin_explicit_outlives = outlives requirements can be inferred
 
 lint_builtin_export_name_fn = declaration of a function with `export_name`
 lint_builtin_export_name_method = declaration of a method with `export_name`
-
 lint_builtin_export_name_static = declaration of a static with `export_name`
+
+lint_builtin_global_asm = usage of `core::arch::global_asm`
+lint_builtin_global_macro_unsafety = using this macro is unsafe even though it does not need an `unsafe` block
+
 lint_builtin_impl_unsafe_method = implementation of an `unsafe` method
 
 lint_builtin_incomplete_features = the feature `{$name}` is incomplete and may not be safe to use and/or cause compiler crashes

compiler/rustc_lint/src/builtin.rs

@@ -393,6 +393,10 @@ impl EarlyLintPass for UnsafeCode {
                 }
             }
 
+            ast::ItemKind::GlobalAsm(..) => {
+                self.report_unsafe(cx, it.span, BuiltinUnsafe::GlobalAsm);
+            }
+
             _ => {}
         }
     }

compiler/rustc_lint/src/lints.rs

@@ -114,6 +114,9 @@ pub enum BuiltinUnsafe {
     DeclUnsafeMethod,
     #[diag(lint_builtin_impl_unsafe_method)]
     ImplUnsafeMethod,
+    #[diag(lint_builtin_global_asm)]
+    #[note(lint_builtin_global_macro_unsafety)]
+    GlobalAsm,
 }
 
 #[derive(LintDiagnostic)]

compiler/rustc_metadata/src/creader.rs

@@ -1070,16 +1070,6 @@ impl<'a, 'tcx> CrateLoader<'a, 'tcx> {
     pub fn maybe_process_path_extern(&mut self, name: Symbol) -> Option<CrateNum> {
         self.maybe_resolve_crate(name, CrateDepKind::Explicit, None).ok()
     }
-
-    pub fn unload_unused_crates(&mut self) {
-        for opt_cdata in &mut self.cstore.metas {
-            if let Some(cdata) = opt_cdata
-                && !cdata.used()
-            {
-                *opt_cdata = None;
-            }
-        }
-    }
 }
 
 fn global_allocator_spans(krate: &ast::Crate) -> Vec<Span> {

compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs

@@ -519,6 +519,16 @@ pub(in crate::rmeta) fn provide(providers: &mut Providers) {
             tcx.untracked().cstore.freeze();
             tcx.arena.alloc_from_iter(CStore::from_tcx(tcx).iter_crate_data().map(|(cnum, _)| cnum))
         },
+        used_crates: |tcx, ()| {
+            // The list of loaded crates is now frozen in query cache,
+            // so make sure cstore is not mutably accessed from here on.
+            tcx.untracked().cstore.freeze();
+            tcx.arena.alloc_from_iter(
+                CStore::from_tcx(tcx)
+                    .iter_crate_data()
+                    .filter_map(|(cnum, data)| data.used().then_some(cnum)),
+            )
+        },
         ..providers.queries
     };
     provide_extern(&mut providers.extern_queries);

compiler/rustc_middle/src/query/mod.rs

@@ -1872,6 +1872,13 @@ rustc_queries! {
         eval_always
         desc { "fetching all foreign CrateNum instances" }
     }
+    // Crates that are loaded non-speculatively (not for diagnostics or doc links).
+    // FIXME: This is currently only used for collecting lang items, but should be used instead of
+    // `crates` in most other cases too.
+    query used_crates(_: ()) -> &'tcx [CrateNum] {
+        eval_always
+        desc { "fetching `CrateNum`s for all crates loaded non-speculatively" }
+    }
 
     /// A list of all traits in a crate, used by rustdoc and error reporting.
     query traits(_: CrateNum) -> &'tcx [DefId] {

compiler/rustc_mir_transform/src/const_prop_lint.rs renamed to compiler/rustc_mir_transform/src/known_panics_lint.rs

@@ -1,5 +1,8 @@
-//! Propagates constants for early reporting of statically known
-//! assertion failures
+//! A lint that checks for known panics like
+//! overflows, division by zero,
+//! out-of-bound access etc.
+//! Uses const propagation to determine the
+//! values of operands during checks.
 
 use std::fmt::Debug;
 
@@ -21,9 +24,9 @@ use crate::dataflow_const_prop::DummyMachine;
 use crate::errors::{AssertLint, AssertLintKind};
 use crate::MirLint;
 
-pub struct ConstPropLint;
+pub struct KnownPanicsLint;
 
-impl<'tcx> MirLint<'tcx> for ConstPropLint {
+impl<'tcx> MirLint<'tcx> for KnownPanicsLint {
     fn run_lint(&self, tcx: TyCtxt<'tcx>, body: &Body<'tcx>) {
         if body.tainted_by_errors.is_some() {
             return;
@@ -37,31 +40,28 @@ impl<'tcx> MirLint<'tcx> for ConstPropLint {
         // Only run const prop on functions, methods, closures and associated constants
         if !is_fn_like && !is_assoc_const {
             // skip anon_const/statics/consts because they'll be evaluated by miri anyway
-            trace!("ConstPropLint skipped for {:?}", def_id);
+            trace!("KnownPanicsLint skipped for {:?}", def_id);
             return;
         }
 
         // FIXME(welseywiser) const prop doesn't work on coroutines because of query cycles
         // computing their layout.
         if tcx.is_coroutine(def_id.to_def_id()) {
-            trace!("ConstPropLint skipped for coroutine {:?}", def_id);
+            trace!("KnownPanicsLint skipped for coroutine {:?}", def_id);
             return;
         }
 
-        trace!("ConstPropLint starting for {:?}", def_id);
+        trace!("KnownPanicsLint starting for {:?}", def_id);
 
-        // FIXME(oli-obk, eddyb) Optimize locals (or even local paths) to hold
-        // constants, instead of just checking for const-folding succeeding.
-        // That would require a uniform one-def no-mutation analysis
-        // and RPO (or recursing when needing the value of a local).
         let mut linter = ConstPropagator::new(body, tcx);
         linter.visit_body(body);
 
-        trace!("ConstPropLint done for {:?}", def_id);
+        trace!("KnownPanicsLint done for {:?}", def_id);
     }
 }
 
-/// Finds optimization opportunities on the MIR.
+/// Visits MIR nodes, performs const propagation
+/// and runs lint checks as it goes
 struct ConstPropagator<'mir, 'tcx> {
     ecx: InterpCx<'mir, 'tcx, DummyMachine>,
     tcx: TyCtxt<'tcx>,
@@ -238,7 +238,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
                 // dedicated error variants should be introduced instead.
                 assert!(
                     !error.kind().formatted_string(),
-                    "const-prop encountered formatting error: {}",
+                    "known panics lint encountered formatting error: {}",
                     format_interp_error(self.ecx.tcx.dcx(), error),
                 );
                 None
@@ -253,7 +253,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
             return None;
         }
 
-        // Normalization needed b/c const prop lint runs in
+        // Normalization needed b/c known panics lint runs in
         // `mir_drops_elaborated_and_const_checked`, which happens before
         // optimized MIR. Only after optimizing the MIR can we guarantee
         // that the `RevealAll` pass has happened and that the body's consts
@@ -864,6 +864,8 @@ pub enum ConstPropMode {
     NoPropagation,
 }
 
+/// A visitor that determines locals in a MIR body
+/// that can be const propagated
 pub struct CanConstProp {
     can_const_prop: IndexVec<Local, ConstPropMode>,
     // False at the beginning. Once set, no more assignments are allowed to that local.

compiler/rustc_mir_transform/src/lib.rs

@@ -59,7 +59,6 @@ mod remove_place_mention;
 mod add_subtyping_projections;
 pub mod cleanup_post_borrowck;
 mod const_debuginfo;
-mod const_prop_lint;
 mod copy_prop;
 mod coroutine;
 mod cost_checker;
@@ -83,6 +82,7 @@ mod gvn;
 pub mod inline;
 mod instsimplify;
 mod jump_threading;
+mod known_panics_lint;
 mod large_enums;
 mod lint;
 mod lower_intrinsics;
@@ -533,7 +533,7 @@ fn run_runtime_lowering_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         &elaborate_box_derefs::ElaborateBoxDerefs,
         &coroutine::StateTransform,
         &add_retag::AddRetag,
-        &Lint(const_prop_lint::ConstPropLint),
+        &Lint(known_panics_lint::KnownPanicsLint),
     ];
     pm::run_passes_no_validate(tcx, body, passes, Some(MirPhase::Runtime(RuntimePhase::Initial)));
 }

compiler/rustc_passes/src/lang_items.rs

@@ -250,7 +250,7 @@ fn get_lang_items(tcx: TyCtxt<'_>, (): ()) -> LanguageItems {
     let mut collector = LanguageItemCollector::new(tcx, resolver);
 
     // Collect lang items in other crates.
-    for &cnum in tcx.crates(()).iter() {
+    for &cnum in tcx.used_crates(()).iter() {
         for &(def_id, lang_item) in tcx.defined_lang_items(cnum).iter() {
             collector.collect_item(lang_item, def_id, None);
         }