Auto merge of #146158 - Zalathar:rollup-2fg79po, r=Zalathar

Rollup of 16 pull requests

Successful merges:

 - #143725 (core: add Peekable::next_if_map)
 - #145209 (Stabilize `path_add_extension`)
 - #145342 (fix drop scope for `super let` bindings within `if let`)
 - #145750 (raw_vec.rs: Remove superfluous fn alloc_guard)
 - #145962 (Ensure we emit an allocator shim when only some crate types need one)
 - #145963 (Add LSX accelerated implementation for source file analysis)
 - #146054 (add `#[must_use]` to `array::repeat`)
 - #146090 (Derive `PartialEq` for `InvisibleOrigin`)
 - #146120 (Correct typo in `rustc_errors` comment)
 - #146127 (Rename `ToolRustc` to `ToolRustcPrivate`)
 - #146133 (Revert "Make `lto` and `linker-plugin-lto` work the same for `compiler_builtins`)
 - #146134 (llvm: nvptx: Layout update to match LLVM)
 - #146136 (docs(std): add missing closing code block fences in doc comments)
 - #146137 (Disallow frontmatter in `--cfg` and `--check-cfg` arguments)
 - #146140 (compiletest: cygwin follows windows in using PATH for dynamic libraries)
 - #146156 (miri subtree update)

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

Author: bors

Cargo.lock

@@ -3204,9 +3204,9 @@ dependencies = [
 
 [[package]]
 name = "rustc-build-sysroot"
-version = "0.5.9"
+version = "0.5.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fdb13874a0e55baf4ac3d49d38206aecb31a55b75d6c4d04fd850b53942c8cc8"
+checksum = "3b881c015c729b43105bbd3702a9bdecee28fafaa21126d1d62e454ec011a4b7"
 dependencies = [
  "anyhow",
  "rustc_version",

compiler/rustc_ast/src/token.rs

@@ -22,8 +22,7 @@ pub enum CommentKind {
     Block,
 }
 
-// This type must not implement `Hash` due to the unusual `PartialEq` impl below.
-#[derive(Copy, Clone, Debug, Encodable, Decodable, HashStable_Generic)]
+#[derive(Copy, Clone, PartialEq, Debug, Encodable, Decodable, HashStable_Generic)]
 pub enum InvisibleOrigin {
     // From the expansion of a metavariable in a declarative macro.
     MetaVar(MetaVarKind),
@@ -45,20 +44,6 @@ impl InvisibleOrigin {
     }
 }
 
-impl PartialEq for InvisibleOrigin {
-    #[inline]
-    fn eq(&self, _other: &InvisibleOrigin) -> bool {
-        // When we had AST-based nonterminals we couldn't compare them, and the
-        // old `Nonterminal` type had an `eq` that always returned false,
-        // resulting in this restriction:
-        // https://doc.rust-lang.org/nightly/reference/macros-by-example.html#forwarding-a-matched-fragment
-        // This `eq` emulates that behaviour. We could consider lifting this
-        // restriction now but there are still cases involving invisible
-        // delimiters that make it harder than it first appears.
-        false
-    }
-}
-
 /// Annoyingly similar to `NonterminalKind`, but the slight differences are important.
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Encodable, Decodable, Hash, HashStable_Generic)]
 pub enum MetaVarKind {
@@ -142,7 +127,8 @@ impl Delimiter {
         }
     }
 
-    // This exists because `InvisibleOrigin`s should be compared. It is only used for assertions.
+    // This exists because `InvisibleOrigin`s should not be compared. It is only used for
+    // assertions.
     pub fn eq_ignoring_invisible_origin(&self, other: &Delimiter) -> bool {
         match (self, other) {
             (Delimiter::Parenthesis, Delimiter::Parenthesis) => true,

compiler/rustc_codegen_llvm/src/context.rs

@@ -217,6 +217,10 @@ pub(crate) unsafe fn create_module<'ll>(
             // LLVM 22.0 updated the default layout on avr: https://github.com/llvm/llvm-project/pull/153010
             target_data_layout = target_data_layout.replace("n8:16", "n8")
         }
+        if sess.target.arch == "nvptx64" {
+            // LLVM 22 updated the NVPTX layout to indicate 256-bit vector load/store: https://github.com/llvm/llvm-project/pull/155198
+            target_data_layout = target_data_layout.replace("-i256:256", "");
+        }
     }
 
     // Ensure the data-layout values hardcoded remain the defaults.

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -58,6 +58,7 @@ use super::linker::{self, Linker};
 use super::metadata::{MetadataPosition, create_wrapper_file};
 use super::rpath::{self, RPathConfig};
 use super::{apple, versioned_llvm_target};
+use crate::base::needs_allocator_shim_for_linking;
 use crate::{
     CodegenResults, CompiledModule, CrateInfo, NativeLib, errors, looks_like_rust_object_file,
 };
@@ -2080,9 +2081,17 @@ fn add_local_crate_regular_objects(cmd: &mut dyn Linker, codegen_results: &Codeg
 }
 
 /// Add object files for allocator code linked once for the whole crate tree.
-fn add_local_crate_allocator_objects(cmd: &mut dyn Linker, codegen_results: &CodegenResults) {
-    if let Some(obj) = codegen_results.allocator_module.as_ref().and_then(|m| m.object.as_ref()) {
-        cmd.add_object(obj);
+fn add_local_crate_allocator_objects(
+    cmd: &mut dyn Linker,
+    codegen_results: &CodegenResults,
+    crate_type: CrateType,
+) {
+    if needs_allocator_shim_for_linking(&codegen_results.crate_info.dependency_formats, crate_type)
+    {
+        if let Some(obj) = codegen_results.allocator_module.as_ref().and_then(|m| m.object.as_ref())
+        {
+            cmd.add_object(obj);
+        }
     }
 }
 
@@ -2281,7 +2290,7 @@ fn linker_with_args(
         codegen_results,
         metadata,
     );
-    add_local_crate_allocator_objects(cmd, codegen_results);
+    add_local_crate_allocator_objects(cmd, codegen_results, crate_type);
 
     // Avoid linking to dynamic libraries unless they satisfy some undefined symbols
     // at the point at which they are specified on the command line.

compiler/rustc_codegen_ssa/src/back/linker.rs

@@ -11,8 +11,9 @@ use rustc_metadata::{
 };
 use rustc_middle::bug;
 use rustc_middle::middle::dependency_format::Linkage;
-use rustc_middle::middle::exported_symbols;
-use rustc_middle::middle::exported_symbols::{ExportedSymbol, SymbolExportInfo, SymbolExportKind};
+use rustc_middle::middle::exported_symbols::{
+    self, ExportedSymbol, SymbolExportInfo, SymbolExportKind, SymbolExportLevel,
+};
 use rustc_middle::ty::TyCtxt;
 use rustc_session::Session;
 use rustc_session::config::{self, CrateType, DebugInfo, LinkerPluginLto, Lto, OptLevel, Strip};
@@ -22,6 +23,8 @@ use tracing::{debug, warn};
 
 use super::command::Command;
 use super::symbol_export;
+use crate::back::symbol_export::allocator_shim_symbols;
+use crate::base::needs_allocator_shim_for_linking;
 use crate::errors;
 
 #[cfg(test)]
@@ -1827,7 +1830,7 @@ fn exported_symbols_for_non_proc_macro(
     let export_threshold = symbol_export::crates_export_threshold(&[crate_type]);
     for_each_exported_symbols_include_dep(tcx, crate_type, |symbol, info, cnum| {
         // Do not export mangled symbols from cdylibs and don't attempt to export compiler-builtins
-        // from any cdylib. The latter doesn't work anyway as we use hidden visibility for
+        // from any dylib. The latter doesn't work anyway as we use hidden visibility for
         // compiler-builtins. Most linkers silently ignore it, but ld64 gives a warning.
         if info.level.is_below_threshold(export_threshold) && !tcx.is_compiler_builtins(cnum) {
             symbols.push((
@@ -1838,6 +1841,14 @@ fn exported_symbols_for_non_proc_macro(
         }
     });
 
+    // Mark allocator shim symbols as exported only if they were generated.
+    if export_threshold == SymbolExportLevel::Rust
+        && needs_allocator_shim_for_linking(tcx.dependency_formats(()), crate_type)
+        && tcx.allocator_kind(()).is_some()
+    {
+        symbols.extend(allocator_shim_symbols(tcx));
+    }
+
     symbols
 }
 

compiler/rustc_codegen_ssa/src/back/lto.rs

@@ -8,8 +8,9 @@ use rustc_middle::ty::TyCtxt;
 use rustc_session::config::{CrateType, Lto};
 use tracing::info;
 
-use crate::back::symbol_export::{self, symbol_name_for_instance_in_crate};
+use crate::back::symbol_export::{self, allocator_shim_symbols, symbol_name_for_instance_in_crate};
 use crate::back::write::CodegenContext;
+use crate::base::allocator_kind_for_codegen;
 use crate::errors::{DynamicLinkingWithLTO, LtoDisallowed, LtoDylib, LtoProcMacro};
 use crate::traits::*;
 
@@ -115,6 +116,11 @@ pub(super) fn exported_symbols_for_lto(
         }
     }
 
+    // Mark allocator shim symbols as exported only if they were generated.
+    if export_threshold == SymbolExportLevel::Rust && allocator_kind_for_codegen(tcx).is_some() {
+        symbols_below_threshold.extend(allocator_shim_symbols(tcx).map(|(name, _kind)| name));
+    }
+
     symbols_below_threshold
 }
 

compiler/rustc_codegen_ssa/src/back/symbol_export.rs

@@ -18,7 +18,7 @@ use rustc_symbol_mangling::mangle_internal_symbol;
 use rustc_target::spec::TlsModel;
 use tracing::debug;
 
-use crate::base::allocator_kind_for_codegen;
+use crate::back::symbol_export;
 
 fn threshold(tcx: TyCtxt<'_>) -> SymbolExportLevel {
     crates_export_threshold(tcx.crate_types())
@@ -217,31 +217,6 @@ fn exported_non_generic_symbols_provider_local<'tcx>(
         ));
     }
 
-    // Mark allocator shim symbols as exported only if they were generated.
-    if allocator_kind_for_codegen(tcx).is_some() {
-        for symbol_name in ALLOCATOR_METHODS
-            .iter()
-            .map(|method| mangle_internal_symbol(tcx, global_fn_name(method.name).as_str()))
-            .chain([
-                mangle_internal_symbol(tcx, "__rust_alloc_error_handler"),
-                mangle_internal_symbol(tcx, OomStrategy::SYMBOL),
-                mangle_internal_symbol(tcx, NO_ALLOC_SHIM_IS_UNSTABLE),
-            ])
-        {
-            let exported_symbol = ExportedSymbol::NoDefId(SymbolName::new(tcx, &symbol_name));
-
-            symbols.push((
-                exported_symbol,
-                SymbolExportInfo {
-                    level: SymbolExportLevel::Rust,
-                    kind: SymbolExportKind::Text,
-                    used: false,
-                    rustc_std_internal_symbol: true,
-                },
-            ));
-        }
-    }
-
     // Sort so we get a stable incr. comp. hash.
     symbols.sort_by_cached_key(|s| s.0.symbol_name_for_local_instance(tcx));
 
@@ -516,6 +491,31 @@ pub(crate) fn provide(providers: &mut Providers) {
         upstream_monomorphizations_for_provider;
 }
 
+pub(crate) fn allocator_shim_symbols(
+    tcx: TyCtxt<'_>,
+) -> impl Iterator<Item = (String, SymbolExportKind)> {
+    ALLOCATOR_METHODS
+        .iter()
+        .map(move |method| mangle_internal_symbol(tcx, global_fn_name(method.name).as_str()))
+        .chain([
+            mangle_internal_symbol(tcx, "__rust_alloc_error_handler"),
+            mangle_internal_symbol(tcx, OomStrategy::SYMBOL),
+            mangle_internal_symbol(tcx, NO_ALLOC_SHIM_IS_UNSTABLE),
+        ])
+        .map(move |symbol_name| {
+            let exported_symbol = ExportedSymbol::NoDefId(SymbolName::new(tcx, &symbol_name));
+
+            (
+                symbol_export::exporting_symbol_name_for_instance_in_crate(
+                    tcx,
+                    exported_symbol,
+                    LOCAL_CRATE,
+                ),
+                SymbolExportKind::Text,
+            )
+        })
+}
+
 fn symbol_export_level(tcx: TyCtxt<'_>, sym_def_id: DefId) -> SymbolExportLevel {
     // We export anything that's not mangled at the "C" layer as it probably has
     // to do with ABI concerns. We do not, however, apply such treatment to

compiler/rustc_codegen_ssa/src/back/write.rs

@@ -138,12 +138,23 @@ impl ModuleConfig {
 
         let emit_obj = if !should_emit_obj {
             EmitObj::None
-        } else if sess.target.obj_is_bitcode || sess.opts.cg.linker_plugin_lto.enabled() {
+        } else if sess.target.obj_is_bitcode
+            || (sess.opts.cg.linker_plugin_lto.enabled() && !no_builtins)
+        {
             // This case is selected if the target uses objects as bitcode, or
             // if linker plugin LTO is enabled. In the linker plugin LTO case
             // the assumption is that the final link-step will read the bitcode
             // and convert it to object code. This may be done by either the
             // native linker or rustc itself.
+            //
+            // Note, however, that the linker-plugin-lto requested here is
+            // explicitly ignored for `#![no_builtins]` crates. These crates are
+            // specifically ignored by rustc's LTO passes and wouldn't work if
+            // loaded into the linker. These crates define symbols that LLVM
+            // lowers intrinsics to, and these symbol dependencies aren't known
+            // until after codegen. As a result any crate marked
+            // `#![no_builtins]` is assumed to not participate in LTO and
+            // instead goes on to generate object code.
             EmitObj::Bitcode
         } else if need_bitcode_in_object(tcx) {
             EmitObj::ObjectCode(BitcodeSection::Full)

compiler/rustc_codegen_ssa/src/base.rs

@@ -17,6 +17,7 @@ use rustc_hir::lang_items::LangItem;
 use rustc_hir::{ItemId, Target};
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrs;
 use rustc_middle::middle::debugger_visualizer::{DebuggerVisualizerFile, DebuggerVisualizerType};
+use rustc_middle::middle::dependency_format::Dependencies;
 use rustc_middle::middle::exported_symbols::{self, SymbolExportKind};
 use rustc_middle::middle::lang_items;
 use rustc_middle::mir::BinOp;
@@ -630,14 +631,30 @@ pub fn allocator_kind_for_codegen(tcx: TyCtxt<'_>) -> Option<AllocatorKind> {
     // If the crate doesn't have an `allocator_kind` set then there's definitely
     // no shim to generate. Otherwise we also check our dependency graph for all
     // our output crate types. If anything there looks like its a `Dynamic`
-    // linkage, then it's already got an allocator shim and we'll be using that
-    // one instead. If nothing exists then it's our job to generate the
-    // allocator!
-    let any_dynamic_crate = tcx.dependency_formats(()).iter().any(|(_, list)| {
+    // linkage for all crate types we may link as, then it's already got an
+    // allocator shim and we'll be using that one instead. If nothing exists
+    // then it's our job to generate the allocator! If crate types disagree
+    // about whether an allocator shim is necessary or not, we generate one
+    // and let needs_allocator_shim_for_linking decide at link time whether or
+    // not to use it for any particular linker invocation.
+    let all_crate_types_any_dynamic_crate = tcx.dependency_formats(()).iter().all(|(_, list)| {
         use rustc_middle::middle::dependency_format::Linkage;
         list.iter().any(|&linkage| linkage == Linkage::Dynamic)
     });
-    if any_dynamic_crate { None } else { tcx.allocator_kind(()) }
+    if all_crate_types_any_dynamic_crate { None } else { tcx.allocator_kind(()) }
+}
+
+/// Decide if this particular crate type needs an allocator shim linked in.
+/// This may return true even when allocator_kind_for_codegen returns false. In
+/// this case no allocator shim shall be linked.
+pub(crate) fn needs_allocator_shim_for_linking(
+    dependency_formats: &Dependencies,
+    crate_type: CrateType,
+) -> bool {
+    use rustc_middle::middle::dependency_format::Linkage;
+    let any_dynamic_crate =
+        dependency_formats[&crate_type].iter().any(|&linkage| linkage == Linkage::Dynamic);
+    !any_dynamic_crate
 }
 
 pub fn codegen_crate<B: ExtraBackendMethods>(

compiler/rustc_errors/src/lib.rs

@@ -1160,7 +1160,7 @@ impl<'a> DiagCtxtHandle<'a> {
         // - It's only produce with JSON output.
         // - It's not emitted the usual way, via `emit_diagnostic`.
         // - The `$message_type` field is "unused_externs" rather than the usual
-        //   "diagnosic".
+        //   "diagnostic".
         //
         // We count it as a lint error because it has a lint level. The value
         // of `loud` (which comes from "unused-externs" or