Rollup of 16 pull requests

.git-blame-ignore-revs

@@ -33,3 +33,6 @@ c682aa162b0d41e21cc6748f4fecfe01efb69d1f
 1fcae03369abb4c2cc180cd5a49e1f4440a81300
 # Breaking up of compiletest runtest.rs
 60600a6fa403216bfd66e04f948b1822f6450af7
+
+# std: move futex implementations into sys::sync::futex
+7232830d10b6af772e0e4670a2ff61dd23830ed8

.github/pull_request_template.md

@@ -1,5 +1,16 @@
 <!-- homu-ignore:start -->
+
+- [ ] I did not use an LLM to create a change in this PR.
+- [ ] I used an LLM to create a change in this PR, and I have explained below how it was used.
+
 <!--
+Please read our [LLM policy] before opening a PR,
+and check one of the boxes above to indicate whether you've used an LLM.
+If you do not check a box, a reviewer may ask you whether an LLM was involved.
+LLM contributions are not banned, but are held to a higher standard of review and correctness.
+
+[LLM policy]: https://forge.rust-lang.org/policies/llm-usage.html
+
 If this PR is related to an unstable feature or an otherwise tracked effort,
 please link to the relevant tracking issue here. If you don't know of a related
 tracking issue or there are none, feel free to ignore this.

CONTRIBUTING.md

@@ -29,6 +29,15 @@ that you read and understand the [rustc-dev-guide] before making a contribution.
 talks about the different bots in the Rust ecosystem, the Rust development tools,
 bootstrapping, the compiler architecture, source code representation, and more.
 
+## LLM policy
+
+We have a policy for how LLMs are allowed to be used in contributions to `rust-lang/rust`.
+You can read it [on Forge][LLM policy].
+For suggestions about how to use LLMs *well*, and how to review LLM-created PRs, see [the dev-guide][llm-guidance].
+
+[LLM policy]: https://forge.rust-lang.org/policies/llm-usage.html
+[llm-guidance]: https://rustc-dev-guide.rust-lang.org/llm-guidance.html
+
 ## [Getting help](https://rustc-dev-guide.rust-lang.org/getting-started.html#asking-questions)
 
 There are many ways you can get help when you're stuck. Rust has two platforms for this:

Cargo.lock

@@ -3954,6 +3954,7 @@ dependencies = [
  "rustc_errors",
  "rustc_expand",
  "rustc_feature",
+ "rustc_hir",
  "rustc_hir_analysis",
  "rustc_hir_pretty",
  "rustc_index",
@@ -4414,7 +4415,6 @@ dependencies = [
  "rustc_graphviz",
  "rustc_hashes",
  "rustc_hir",
- "rustc_hir_pretty",
  "rustc_index",
  "rustc_lint_defs",
  "rustc_macros",
@@ -4621,7 +4621,7 @@ dependencies = [
  "rustc_middle",
  "rustc_session",
  "rustc_span",
- "rustc_ty_utils",
+ "rustc_ty_walk",
  "tracing",
 ]
 
@@ -4908,6 +4908,17 @@ dependencies = [
  "rustc_span",
  "rustc_target",
  "rustc_trait_selection",
+ "rustc_ty_walk",
+ "tracing",
+]
+
+[[package]]
+name = "rustc_ty_walk"
+version = "0.0.0"
+dependencies = [
+ "rustc_hir",
+ "rustc_middle",
+ "rustc_span",
  "tracing",
 ]
 

compiler/rustc_attr_parsing/src/attributes/traits.rs

@@ -3,6 +3,7 @@ use std::mem;
 use rustc_feature::AttributeStability;
 
 use super::prelude::*;
+use crate::AttributeSafety;
 use crate::attributes::{NoArgsAttributeParser, SingleAttributeParser};
 use crate::context::AcceptContext;
 use crate::parser::ArgParser;
@@ -98,12 +99,18 @@ impl NoArgsAttributeParser for RustcSpecializationTraitParser {
     const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::RustcSpecializationTrait;
 }
 
-pub(crate) struct RustcUnsafeSpecializationMarkerParser;
-impl NoArgsAttributeParser for RustcUnsafeSpecializationMarkerParser {
-    const PATH: &[Symbol] = &[sym::rustc_unsafe_specialization_marker];
+pub(crate) struct RustcAllowLifetimeDependentSpecializationParser;
+impl NoArgsAttributeParser for RustcAllowLifetimeDependentSpecializationParser {
+    const PATH: &[Symbol] = &[sym::rustc_allow_lifetime_dependent_specialization];
     const ALLOWED_TARGETS: AllowedTargets<'_> = AllowedTargets::AllowList(&[Allow(Target::Trait)]);
     const STABILITY: AttributeStability = unstable!(rustc_attrs);
-    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::RustcUnsafeSpecializationMarker;
+    const CREATE: fn(Span) -> AttributeKind =
+        |_| AttributeKind::RustcAllowLifetimeDependentSpecialization;
+    const SAFETY: AttributeSafety = AttributeSafety::Unsafe {
+        note: "this attribute requires `unsafe` because lifetime constraints from \
+            the implementations of the trait are not considered when specializing",
+        unsafe_since: None,
+    };
 }
 
 // Coherence

compiler/rustc_attr_parsing/src/context.rs

@@ -295,6 +295,7 @@ attribute_parsers!(
         Single<WithoutArgs<RustcAllocatorParser>>,
         Single<WithoutArgs<RustcAllocatorZeroedParser>>,
         Single<WithoutArgs<RustcAllowIncoherentImplParser>>,
+        Single<WithoutArgs<RustcAllowLifetimeDependentSpecializationParser>>,
         Single<WithoutArgs<RustcAsPtrParser>>,
         Single<WithoutArgs<RustcCanonicalSymbolParser>>,
         Single<WithoutArgs<RustcCaptureAnalysisParser>>,
@@ -355,7 +356,6 @@ attribute_parsers!(
         Single<WithoutArgs<RustcStrictCoherenceParser>>,
         Single<WithoutArgs<RustcTestEntrypointMarkerParser>>,
         Single<WithoutArgs<RustcTrivialFieldReadsParser>>,
-        Single<WithoutArgs<RustcUnsafeSpecializationMarkerParser>>,
         Single<WithoutArgs<SplatParser>>,
         Single<WithoutArgs<ThreadLocalParser>>,
         Single<WithoutArgs<TrackCallerParser>>,

compiler/rustc_attr_parsing/src/parser.rs

@@ -489,7 +489,7 @@ fn expr_to_lit<'sess>(
     }
 }
 
-/// Whether expansions of `expr` metavariables from decrarative macros
+/// Whether expansions of `expr` metavariables from declarative  macros
 /// are permitted. Used when parsing meta items; currently, only `cfg` predicates
 /// enable this option
 #[derive(Clone, Copy, PartialEq, Eq)]

compiler/rustc_codegen_cranelift/src/lib.rs

@@ -41,8 +41,8 @@ use rustc_codegen_ssa::traits::CodegenBackend;
 use rustc_codegen_ssa::{CompiledModules, CrateInfo, TargetConfig, back};
 use rustc_log::tracing::info;
 use rustc_middle::dep_graph::WorkProductMap;
-use rustc_session::Session;
 use rustc_session::config::{NATIVE_CPU, OutputFilenames};
+use rustc_session::{IncrCompSession, Session};
 use rustc_span::{Symbol, sym};
 use rustc_target::spec::{Arch, CfgAbi, Env, Os};
 
@@ -233,13 +233,14 @@ impl CodegenBackend for CraneliftCodegenBackend {
         &self,
         ongoing_codegen: Box<dyn Any>,
         sess: &Session,
+        incr_comp_session: Option<&IncrCompSession>,
         _outputs: &OutputFilenames,
         crate_info: &CrateInfo,
     ) -> (CompiledModules, WorkProductMap) {
         ongoing_codegen
             .downcast::<rustc_codegen_ssa::back::write::OngoingCodegen<driver::aot::AotDriver>>()
             .unwrap()
-            .join(sess, crate_info)
+            .join(sess, incr_comp_session, crate_info)
     }
 
     fn fallback_intrinsics(&self) -> Vec<Symbol> {

compiler/rustc_codegen_gcc/src/lib.rs

@@ -94,8 +94,8 @@ use rustc_errors::{DiagCtxt, DiagCtxtHandle};
 use rustc_middle::dep_graph::{WorkProduct, WorkProductMap};
 use rustc_middle::ty::TyCtxt;
 use rustc_middle::util::Providers;
-use rustc_session::Session;
 use rustc_session::config::{OptLevel, OutputFilenames};
+use rustc_session::{IncrCompSession, Session};
 use rustc_span::{Symbol, sym};
 use rustc_target::spec::{Arch, RelocModel};
 use tempfile::TempDir;
@@ -297,13 +297,14 @@ impl CodegenBackend for GccCodegenBackend {
         &self,
         ongoing_codegen: Box<dyn Any>,
         sess: &Session,
+        incr_comp_session: Option<&IncrCompSession>,
         _outputs: &OutputFilenames,
         crate_info: &CrateInfo,
     ) -> (CompiledModules, WorkProductMap) {
         ongoing_codegen
             .downcast::<rustc_codegen_ssa::back::write::OngoingCodegen<GccCodegenBackend>>()
             .expect("Expected GccCodegenBackend's OngoingCodegen, found Box<Any>")
-            .join(sess, crate_info)
+            .join(sess, incr_comp_session, crate_info)
     }
 
     fn target_config(&self, sess: &Session) -> TargetConfig {

compiler/rustc_codegen_llvm/src/builder/autodiff.rs

@@ -45,18 +45,13 @@ pub(crate) fn adjust_activity_to_abi<'tcx>(
     let mut del_activities = 0;
     for (i, ty) in sig.inputs().iter().enumerate() {
         if let Some(inner_ty) = ty.builtin_deref(true) {
-            if inner_ty.is_slice() {
+            let tail_ty = tcx.struct_tail_for_codegen(inner_ty, typing_env);
+            if let ty::Slice(element_ty) = tail_ty.kind() {
                 // Now we need to figure out the size of each slice element in memory to allow
                 // safety checks and usability improvements in the backend.
-                let sty = match inner_ty.builtin_index() {
-                    Some(sty) => sty,
-                    None => {
-                        panic!("slice element type unknown");
-                    }
-                };
                 let pci = PseudoCanonicalInput {
                     typing_env: TypingEnv::fully_monomorphized(),
-                    value: sty,
+                    value: *element_ty,
                 };
 
                 let layout = tcx.layout_of(pci);

compiler/rustc_codegen_llvm/src/lib.rs

@@ -38,8 +38,8 @@ use rustc_metadata::EncodedMetadata;
 use rustc_middle::dep_graph::{WorkProduct, WorkProductMap};
 use rustc_middle::ty::TyCtxt;
 use rustc_middle::util::Providers;
-use rustc_session::Session;
 use rustc_session::config::{OptLevel, OutputFilenames, PrintKind, PrintRequest};
+use rustc_session::{IncrCompSession, Session};
 use rustc_span::{Symbol, sym};
 use rustc_target::spec::{RelocModel, TlsModel};
 
@@ -380,13 +380,14 @@ impl CodegenBackend for LlvmCodegenBackend {
         &self,
         ongoing_codegen: Box<dyn Any>,
         sess: &Session,
+        incr_comp_session: Option<&IncrCompSession>,
         outputs: &OutputFilenames,
         crate_info: &CrateInfo,
     ) -> (CompiledModules, WorkProductMap) {
         let (compiled_modules, work_products) = ongoing_codegen
             .downcast::<rustc_codegen_ssa::back::write::OngoingCodegen<LlvmCodegenBackend>>()
             .expect("Expected LlvmCodegenBackend's OngoingCodegen, found Box<Any>")
-            .join(sess, crate_info);
+            .join(sess, incr_comp_session, crate_info);
 
         if sess.opts.unstable_opts.llvm_time_trace {
             sess.time("llvm_dump_timing_file", || {

compiler/rustc_codegen_ssa/src/back/write.rs

@@ -21,11 +21,11 @@ use rustc_metadata::fs::copy_to_stdout;
 use rustc_middle::bug;
 use rustc_middle::dep_graph::{WorkProduct, WorkProductMap};
 use rustc_middle::ty::TyCtxt;
-use rustc_session::Session;
 use rustc_session::config::{
     self, CrateType, Lto, OptLevel, OutFileName, OutputFilenames, OutputType, Passes,
     SwitchWithOptPath,
 };
+use rustc_session::{IncrCompSession, Session};
 use rustc_span::source_map::SourceMap;
 use rustc_span::{FileName, InnerSpan, Span, SpanData};
 use rustc_target::spec::{MergeFunctions, SanitizerSet};
@@ -465,6 +465,7 @@ pub(crate) fn start_async_codegen<B: WriteBackendMethods>(
 
 fn copy_all_cgu_workproducts_to_incr_comp_cache_dir(
     sess: &Session,
+    incr_comp_session: Option<&IncrCompSession>,
     compiled_modules: &CompiledModules,
 ) -> WorkProductMap {
     let mut work_products = WorkProductMap::default();
@@ -498,6 +499,7 @@ fn copy_all_cgu_workproducts_to_incr_comp_cache_dir(
         }
         let (id, product) = copy_cgu_workproduct_to_incr_comp_cache_dir(
             sess,
+            incr_comp_session.unwrap(),
             &module.name,
             files.as_slice(),
             &module.links_from_incr_cache,
@@ -1294,7 +1296,10 @@ fn start_executing_work<B: WriteBackendMethods>(
         time_trace: sess.opts.unstable_opts.llvm_time_trace,
         remark: sess.opts.cg.remark.clone(),
         remark_dir,
-        incr_comp_session_dir: sess.incr_comp_session_dir_opt().map(|r| r.clone()),
+        incr_comp_session_dir: tcx
+            .incr_comp_session
+            .as_ref()
+            .map(|incr_comp_session| incr_comp_session.session_directory.clone()),
         output_filenames: Arc::clone(tcx.output_filenames(())),
         module_config: regular_config,
         opt_level,
@@ -2126,7 +2131,12 @@ pub struct OngoingCodegen<B: WriteBackendMethods> {
 }
 
 impl<B: WriteBackendMethods> OngoingCodegen<B> {
-    pub fn join(self, sess: &Session, crate_info: &CrateInfo) -> (CompiledModules, WorkProductMap) {
+    pub fn join(
+        self,
+        sess: &Session,
+        incr_comp_session: Option<&IncrCompSession>,
+        crate_info: &CrateInfo,
+    ) -> (CompiledModules, WorkProductMap) {
         self.shared_emitter_main.check(sess, true);
 
         let maybe_lto_modules = sess.time("join_worker_thread", || match self.coordinator.join() {
@@ -2204,8 +2214,11 @@ impl<B: WriteBackendMethods> OngoingCodegen<B> {
         // out deterministic results.
         compiled_modules.modules.sort_by(|a, b| a.name.cmp(&b.name));
 
-        let work_products =
-            copy_all_cgu_workproducts_to_incr_comp_cache_dir(sess, &compiled_modules);
+        let work_products = copy_all_cgu_workproducts_to_incr_comp_cache_dir(
+            sess,
+            incr_comp_session,
+            &compiled_modules,
+        );
         produce_final_output_artifacts(sess, &compiled_modules, &self.output_filenames);
 
         (compiled_modules, work_products)
@@ -2257,7 +2270,7 @@ pub(crate) fn submit_pre_lto_module_to_llvm<B: WriteBackendMethods>(
     module: CachedModuleCodegen,
 ) {
     let filename = pre_lto_bitcode_filename(&module.name);
-    let bitcode_path = in_incr_comp_dir_sess(tcx.sess, &filename);
+    let bitcode_path = in_incr_comp_dir_sess(tcx.incr_comp_session.unwrap(), &filename);
     // Schedule the module to be loaded
     drop(
         coordinator

compiler/rustc_codegen_ssa/src/traits/backend.rs

@@ -8,8 +8,8 @@ use rustc_metadata::creader::MetadataLoaderDyn;
 use rustc_middle::dep_graph::WorkProductMap;
 use rustc_middle::ty::TyCtxt;
 use rustc_middle::util::Providers;
-use rustc_session::Session;
 use rustc_session::config::{CrateType, OutputFilenames, PrintRequest};
+use rustc_session::{IncrCompSession, Session};
 use rustc_span::Symbol;
 
 use super::CodegenObject;
@@ -127,6 +127,7 @@ pub trait CodegenBackend {
         &self,
         ongoing_codegen: Box<dyn Any>,
         sess: &Session,
+        incr_comp_session: Option<&IncrCompSession>,
         outputs: &OutputFilenames,
         crate_info: &CrateInfo,
     ) -> (CompiledModules, WorkProductMap);

compiler/rustc_driver_impl/Cargo.toml

@@ -16,6 +16,7 @@ rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_errors = { path = "../rustc_errors" }
 rustc_expand = { path = "../rustc_expand" }
 rustc_feature = { path = "../rustc_feature" }
+rustc_hir = { path = "../rustc_hir" }
 rustc_hir_analysis = { path = "../rustc_hir_analysis" }
 rustc_hir_pretty = { path = "../rustc_hir_pretty" }
 rustc_index = { path = "../rustc_index" }

compiler/rustc_driver_impl/src/lib.rs

@@ -337,8 +337,8 @@ pub fn run_compiler(at_args: &[String], callbacks: &mut (dyn Callbacks + Send))
 
         // Linking is done outside the `compiler.enter()` so that the
         // `GlobalCtxt` within `Queries` can be freed as early as possible.
-        if let Some(linker) = linker {
-            linker.link(sess, codegen_backend);
+        if let (Some(linker), incr_comp_session) = linker {
+            linker.link(sess, incr_comp_session, codegen_backend);
         }
     })
 }

compiler/rustc_driver_impl/src/pretty.rs

@@ -7,7 +7,9 @@ use std::io;
 
 use rustc_ast as ast;
 use rustc_ast_pretty::pprust as pprust_ast;
+use rustc_hir::intravisit;
 use rustc_hir_pretty as pprust_hir;
+use rustc_hir_pretty::PpAnn;
 use rustc_middle::bug;
 use rustc_middle::mir::{write_mir_graphviz, write_mir_pretty};
 use rustc_middle::ty::{self, TyCtxt};
@@ -71,7 +73,8 @@ struct HirIdentifiedAnn<'tcx> {
 
 impl<'tcx> pprust_hir::PpAnn for HirIdentifiedAnn<'tcx> {
     fn nested(&self, state: &mut pprust_hir::State<'_>, nested: pprust_hir::Nested) {
-        self.tcx.nested(state, nested)
+        let this = &self.tcx as &dyn intravisit::HirTyCtxt<'_>;
+        this.nested(state, nested)
     }
 
     fn pre(&self, s: &mut pprust_hir::State<'_>, node: pprust_hir::AnnNode<'_>) {
@@ -149,11 +152,12 @@ struct HirTypedAnn<'tcx> {
 
 impl<'tcx> pprust_hir::PpAnn for HirTypedAnn<'tcx> {
     fn nested(&self, state: &mut pprust_hir::State<'_>, nested: pprust_hir::Nested) {
+        let this = &self.tcx as &dyn intravisit::HirTyCtxt<'_>;
         let old_maybe_typeck_results = self.maybe_typeck_results.get();
         if let pprust_hir::Nested::Body(id) = nested {
             self.maybe_typeck_results.set(Some(self.tcx.typeck_body(id)));
         }
-        self.tcx.nested(state, nested);
+        this.nested(state, nested);
         self.maybe_typeck_results.set(old_maybe_typeck_results);
     }
 
@@ -281,7 +285,7 @@ pub fn print<'tcx>(sess: &Session, ppm: PpMode, ex: PrintExtra<'tcx>) {
                 )
             };
             match s {
-                PpHirMode::Normal => f(&tcx),
+                PpHirMode::Normal => f(&(&tcx as &dyn intravisit::HirTyCtxt<'_>) as &dyn PpAnn),
                 PpHirMode::Identified => {
                     let annotation = HirIdentifiedAnn { tcx };
                     f(&annotation)