Rollup of 15 pull requests

.gitignore

@@ -48,7 +48,7 @@ no_llvm_build
 /llvm/
 /mingw-build/
 /build
-/build-rust-analyzer/
+/build-rust-analyzer
 /dist/
 /unicode-downloads
 /target

compiler/rustc_abi/src/extern_abi.rs

@@ -276,6 +276,51 @@ impl ExternAbi {
             _ => CVariadicStatus::NotSupported,
         }
     }
+
+    /// Returns whether the ABI supports guaranteed tail calls.
+    #[cfg(feature = "nightly")]
+    pub fn supports_guaranteed_tail_call(self) -> bool {
+        match self {
+            Self::CmseNonSecureCall | Self::CmseNonSecureEntry => {
+                // See https://godbolt.org/z/9jhdeqErv. The CMSE calling conventions clear registers
+                // before returning, and hence cannot guarantee a tail call.
+                false
+            }
+            Self::AvrInterrupt
+            | Self::AvrNonBlockingInterrupt
+            | Self::Msp430Interrupt
+            | Self::RiscvInterruptM
+            | Self::RiscvInterruptS
+            | Self::X86Interrupt => {
+                // See https://godbolt.org/z/Edfjnxxcq. Interrupts cannot be called directly.
+                false
+            }
+            Self::GpuKernel | Self::PtxKernel => {
+                // See https://godbolt.org/z/jq5TE5jK1.
+                false
+            }
+            Self::Custom => {
+                // This ABI does not support calls at all (except via assembly).
+                false
+            }
+            Self::C { .. }
+            | Self::System { .. }
+            | Self::Rust
+            | Self::RustCall
+            | Self::RustCold
+            | Self::RustInvalid
+            | Self::Unadjusted
+            | Self::EfiApi
+            | Self::Aapcs { .. }
+            | Self::Cdecl { .. }
+            | Self::Stdcall { .. }
+            | Self::Fastcall { .. }
+            | Self::Thiscall { .. }
+            | Self::Vectorcall { .. }
+            | Self::SysV64 { .. }
+            | Self::Win64 { .. } => true,
+        }
+    }
 }
 
 pub fn all_names() -> Vec<&'static str> {

compiler/rustc_codegen_llvm/src/back/write.rs

@@ -683,7 +683,7 @@ pub(crate) unsafe fn llvm_optimize(
         // Here we map the old arguments to the new arguments, with an offset of 1 to make sure
         // that we don't use the newly added `%dyn_ptr`.
         unsafe {
-            llvm::LLVMRustOffloadMapper(cx.llmod(), old_fn, new_fn);
+            llvm::LLVMRustOffloadMapper(old_fn, new_fn);
         }
 
         llvm::set_linkage(new_fn, llvm::get_linkage(old_fn));

compiler/rustc_codegen_llvm/src/llvm/ffi.rs

@@ -2025,7 +2025,7 @@ unsafe extern "C" {
     ) -> &Attribute;
 
     // Operations on functions
-    pub(crate) fn LLVMRustOffloadMapper<'a>(M: &'a Module, Fn: &'a Value, Fn: &'a Value);
+    pub(crate) fn LLVMRustOffloadMapper<'a>(Fn: &'a Value, Fn: &'a Value);
     pub(crate) fn LLVMRustGetOrInsertFunction<'a>(
         M: &'a Module,
         Name: *const c_char,

compiler/rustc_expand/src/base.rs

@@ -1099,6 +1099,9 @@ pub struct Indeterminate;
 pub struct DeriveResolution {
     pub path: ast::Path,
     pub item: Annotatable,
+    // FIXME: currently this field is only used in `is_none`/`is_some` conditions. However, the
+    // `Arc<SyntaxExtension>` will be used if the FIXME in `MacroExpander::fully_expand_fragment`
+    // is completed.
     pub exts: Option<Arc<SyntaxExtension>>,
     pub is_const: bool,
 }

compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp

@@ -144,9 +144,7 @@ extern "C" void LLVMRustPrintStatistics(RustStringRef OutBuf) {
   llvm::PrintStatistics(OS);
 }
 
-extern "C" void LLVMRustOffloadMapper(LLVMModuleRef M, LLVMValueRef OldFn,
-                                      LLVMValueRef NewFn) {
-  llvm::Module *module = llvm::unwrap(M);
+extern "C" void LLVMRustOffloadMapper(LLVMValueRef OldFn, LLVMValueRef NewFn) {
   llvm::Function *oldFn = llvm::unwrap<llvm::Function>(OldFn);
   llvm::Function *newFn = llvm::unwrap<llvm::Function>(NewFn);
 

compiler/rustc_mir_build/src/check_tail_calls.rs

@@ -135,6 +135,10 @@ impl<'tcx> TailCallCkVisitor<'_, 'tcx> {
             self.report_abi_mismatch(expr.span, caller_sig.abi, callee_sig.abi);
         }
 
+        if !callee_sig.abi.supports_guaranteed_tail_call() {
+            self.report_unsupported_abi(expr.span, callee_sig.abi);
+        }
+
         // FIXME(explicit_tail_calls): this currently fails for cases where opaques are used.
         // e.g.
         // ```
@@ -358,6 +362,16 @@ impl<'tcx> TailCallCkVisitor<'_, 'tcx> {
         self.found_errors = Err(err);
     }
 
+    fn report_unsupported_abi(&mut self, sp: Span, callee_abi: ExternAbi) {
+        let err = self
+            .tcx
+            .dcx()
+            .struct_span_err(sp, "ABI does not support guaranteed tail calls")
+            .with_note(format!("`become` is not supported for `extern {callee_abi}` functions"))
+            .emit();
+        self.found_errors = Err(err);
+    }
+
     fn report_signature_mismatch(
         &mut self,
         sp: Span,

compiler/rustc_mir_transform/src/coverage/expansion.rs

@@ -1,7 +1,12 @@
 use rustc_data_structures::fx::{FxIndexMap, FxIndexSet, IndexEntry};
+use rustc_middle::mir;
 use rustc_middle::mir::coverage::BasicCoverageBlock;
 use rustc_span::{ExpnId, ExpnKind, Span};
 
+use crate::coverage::from_mir;
+use crate::coverage::graph::CoverageGraph;
+use crate::coverage::hir_info::ExtractedHirInfo;
+
 #[derive(Clone, Copy, Debug)]
 pub(crate) struct SpanWithBcb {
     pub(crate) span: Span,
@@ -70,6 +75,10 @@ pub(crate) struct ExpnNode {
     pub(crate) spans: Vec<SpanWithBcb>,
     /// Expansions whose call-site is in this expansion.
     pub(crate) child_expn_ids: FxIndexSet<ExpnId>,
+
+    /// Hole spans belonging to this expansion, to be carved out from the
+    /// code spans during span refinement.
+    pub(crate) hole_spans: Vec<Span>,
 }
 
 impl ExpnNode {
@@ -88,17 +97,27 @@ impl ExpnNode {
 
             spans: vec![],
             child_expn_ids: FxIndexSet::default(),
+
+            hole_spans: vec![],
         }
     }
 }
 
-/// Given a collection of span/BCB pairs from potentially-different syntax contexts,
+/// Extracts raw span/BCB pairs from potentially-different syntax contexts, and
 /// arranges them into an "expansion tree" based on their expansion call-sites.
-pub(crate) fn build_expn_tree(spans: impl IntoIterator<Item = SpanWithBcb>) -> ExpnTree {
+pub(crate) fn build_expn_tree(
+    mir_body: &mir::Body<'_>,
+    hir_info: &ExtractedHirInfo,
+    graph: &CoverageGraph,
+) -> ExpnTree {
+    let raw_spans = from_mir::extract_raw_spans_from_mir(mir_body, graph);
+
     let mut nodes = FxIndexMap::default();
     let new_node = |&expn_id: &ExpnId| ExpnNode::new(expn_id);
 
-    for span_with_bcb in spans {
+    for from_mir::RawSpanFromMir { raw_span, bcb } in raw_spans {
+        let span_with_bcb = SpanWithBcb { span: raw_span, bcb };
+
         // Create a node for this span's enclosing expansion, and add the span to it.
         let expn_id = span_with_bcb.span.ctxt().outer_expn();
         let node = nodes.entry(expn_id).or_insert_with_key(new_node);
@@ -123,5 +142,13 @@ pub(crate) fn build_expn_tree(spans: impl IntoIterator<Item = SpanWithBcb>) -> E
         }
     }
 
+    // Associate each hole span (extracted from HIR) with its corresponding
+    // expansion tree node.
+    for &hole_span in &hir_info.hole_spans {
+        let expn_id = hole_span.ctxt().outer_expn();
+        let Some(node) = nodes.get_mut(&expn_id) else { continue };
+        node.hole_spans.push(hole_span);
+    }
+
     ExpnTree { nodes }
 }

compiler/rustc_mir_transform/src/coverage/spans/from_mir.rs → compiler/rustc_mir_transform/src/coverage/from_mir.rs

@@ -142,19 +142,3 @@ fn filtered_terminator_span(terminator: &Terminator<'_>) -> Option<Span> {
         | TerminatorKind::InlineAsm { .. } => Some(terminator.source_info.span),
     }
 }
-
-#[derive(Debug)]
-pub(crate) struct Hole {
-    pub(crate) span: Span,
-}
-
-impl Hole {
-    pub(crate) fn merge_if_overlapping_or_adjacent(&mut self, other: &mut Self) -> bool {
-        if !self.span.overlaps_or_adjacent(other.span) {
-            return false;
-        }
-
-        self.span = self.span.to(other.span);
-        true
-    }
-}

compiler/rustc_mir_transform/src/coverage/mappings.rs

@@ -5,6 +5,7 @@ use rustc_middle::mir::coverage::{
 use rustc_middle::mir::{self, BasicBlock, StatementKind};
 use rustc_middle::ty::TyCtxt;
 
+use crate::coverage::expansion;
 use crate::coverage::graph::CoverageGraph;
 use crate::coverage::hir_info::ExtractedHirInfo;
 use crate::coverage::spans::extract_refined_covspans;
@@ -23,10 +24,12 @@ pub(crate) fn extract_mappings_from_mir<'tcx>(
     hir_info: &ExtractedHirInfo,
     graph: &CoverageGraph,
 ) -> ExtractedMappings {
+    let expn_tree = expansion::build_expn_tree(mir_body, hir_info, graph);
+
     let mut mappings = vec![];
 
     // Extract ordinary code mappings from MIR statement/terminator spans.
-    extract_refined_covspans(tcx, mir_body, hir_info, graph, &mut mappings);
+    extract_refined_covspans(tcx, hir_info, graph, &expn_tree, &mut mappings);
 
     extract_branch_mappings(mir_body, hir_info, graph, &mut mappings);
 

compiler/rustc_mir_transform/src/coverage/mod.rs

@@ -9,6 +9,7 @@ use crate::coverage::mappings::ExtractedMappings;
 
 mod counters;
 mod expansion;
+mod from_mir;
 mod graph;
 mod hir_info;
 mod mappings;

compiler/rustc_mir_transform/src/coverage/spans.rs

@@ -1,22 +1,18 @@
-use rustc_middle::mir;
 use rustc_middle::mir::coverage::{Mapping, MappingKind, START_BCB};
 use rustc_middle::ty::TyCtxt;
 use rustc_span::source_map::SourceMap;
 use rustc_span::{BytePos, DesugaringKind, ExpnId, ExpnKind, MacroKind, Span};
 use tracing::instrument;
 
-use crate::coverage::expansion::{self, ExpnTree, SpanWithBcb};
+use crate::coverage::expansion::{ExpnTree, SpanWithBcb};
 use crate::coverage::graph::{BasicCoverageBlock, CoverageGraph};
 use crate::coverage::hir_info::ExtractedHirInfo;
-use crate::coverage::spans::from_mir::{Hole, RawSpanFromMir};
-
-mod from_mir;
 
 pub(super) fn extract_refined_covspans<'tcx>(
     tcx: TyCtxt<'tcx>,
-    mir_body: &mir::Body<'tcx>,
     hir_info: &ExtractedHirInfo,
     graph: &CoverageGraph,
+    expn_tree: &ExpnTree,
     mappings: &mut Vec<Mapping>,
 ) {
     if hir_info.is_async_fn {
@@ -32,22 +28,32 @@ pub(super) fn extract_refined_covspans<'tcx>(
 
     let &ExtractedHirInfo { body_span, .. } = hir_info;
 
-    let raw_spans = from_mir::extract_raw_spans_from_mir(mir_body, graph);
-    // Use the raw spans to build a tree of expansions for this function.
-    let expn_tree = expansion::build_expn_tree(
-        raw_spans
-            .into_iter()
-            .map(|RawSpanFromMir { raw_span, bcb }| SpanWithBcb { span: raw_span, bcb }),
-    );
+    // If there somehow isn't an expansion tree node corresponding to the
+    // body span, return now and don't create any mappings.
+    let Some(node) = expn_tree.get(body_span.ctxt().outer_expn()) else { return };
 
     let mut covspans = vec![];
-    let mut push_covspan = |covspan: Covspan| {
+
+    for &SpanWithBcb { span, bcb } in &node.spans {
+        covspans.push(Covspan { span, bcb });
+    }
+
+    // For each expansion with its call-site in the body span, try to
+    // distill a corresponding covspan.
+    for &child_expn_id in &node.child_expn_ids {
+        if let Some(covspan) = single_covspan_for_child_expn(tcx, graph, &expn_tree, child_expn_id)
+        {
+            covspans.push(covspan);
+        }
+    }
+
+    covspans.retain(|covspan: &Covspan| {
         let covspan_span = covspan.span;
         // Discard any spans not contained within the function body span.
         // Also discard any spans that fill the entire body, because they tend
         // to represent compiler-inserted code, e.g. implicitly returning `()`.
         if !body_span.contains(covspan_span) || body_span.source_equal(covspan_span) {
-            return;
+            return false;
         }
 
         // Each pushed covspan should have the same context as the body span.
@@ -57,27 +63,11 @@ pub(super) fn extract_refined_covspans<'tcx>(
                 false,
                 "span context mismatch: body_span={body_span:?}, covspan.span={covspan_span:?}"
             );
-            return;
+            return false;
         }
 
-        covspans.push(covspan);
-    };
-
-    if let Some(node) = expn_tree.get(body_span.ctxt().outer_expn()) {
-        for &SpanWithBcb { span, bcb } in &node.spans {
-            push_covspan(Covspan { span, bcb });
-        }
-
-        // For each expansion with its call-site in the body span, try to
-        // distill a corresponding covspan.
-        for &child_expn_id in &node.child_expn_ids {
-            if let Some(covspan) =
-                single_covspan_for_child_expn(tcx, graph, &expn_tree, child_expn_id)
-            {
-                push_covspan(covspan);
-            }
-        }
-    }
+        true
+    });
 
     // Only proceed if we found at least one usable span.
     if covspans.is_empty() {
@@ -107,14 +97,8 @@ pub(super) fn extract_refined_covspans<'tcx>(
     covspans.dedup_by(|b, a| a.span.source_equal(b.span));
 
     // Sort the holes, and merge overlapping/adjacent holes.
-    let mut holes = hir_info
-        .hole_spans
-        .iter()
-        .copied()
-        // Discard any holes that aren't directly visible within the body span.
-        .filter(|&hole_span| body_span.contains(hole_span) && body_span.eq_ctxt(hole_span))
-        .map(|span| Hole { span })
-        .collect::<Vec<_>>();
+    let mut holes = node.hole_spans.iter().copied().map(|span| Hole { span }).collect::<Vec<_>>();
+
     holes.sort_by(|a, b| compare_spans(a.span, b.span));
     holes.dedup_by(|b, a| a.merge_if_overlapping_or_adjacent(b));
 
@@ -295,3 +279,19 @@ fn ensure_non_empty_span(source_map: &SourceMap, span: Span) -> Option<Span> {
         })
         .ok()?
 }
+
+#[derive(Debug)]
+struct Hole {
+    span: Span,
+}
+
+impl Hole {
+    fn merge_if_overlapping_or_adjacent(&mut self, other: &mut Self) -> bool {
+        if !self.span.overlaps_or_adjacent(other.span) {
+            return false;
+        }
+
+        self.span = self.span.to(other.span);
+        true
+    }
+}

compiler/rustc_resolve/src/ident.rs

@@ -458,14 +458,11 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                         let mut result = Err(Determinacy::Determined);
                         for derive in parent_scope.derives {
                             let parent_scope = &ParentScope { derives: &[], ..*parent_scope };
-                            match this.reborrow().resolve_macro_path(
+                            match this.reborrow().resolve_derive_macro_path(
                                 derive,
-                                MacroKind::Derive,
                                 parent_scope,
-                                true,
                                 force,
                                 ignore_import,
-                                None,
                             ) {
                                 Ok((Some(ext), _)) => {
                                     if ext.helper_attrs.contains(&ident.name) {