Auto merge of #148931 - Zalathar:rollup-yfyhpcw, r=Zalathar

Rollup of 15 pull requests

Successful merges:

 - #148543 (Correctly link to associated trait items in reexports)
 - #148808 (Some resolve cleanups)
 - #148812 (coverage: Associate hole spans with expansion tree nodes )
 - #148826 (CStr docs: Fix CStr vs &CStr confusion)
 - #148850 (Implement `Read::read_array`)
 - #148867 (Refactor `Box::take`)
 - #148870 (Remove unused LLVMModuleRef argument)
 - #148878 (error when ABI does not support guaranteed tail calls)
 - #148901 (Disable rustdoc-test-builder test partially for SGX target.)
 - #148902 (add missing s390x target feature to std detect test)
 - #148904 (waffle: stop watching codegen ssa)
 - #148906 (Expose fmt::Arguments::from_str as unstable.)
 - #148907 (add assembly test for infinite recursion with `become`)
 - #148928 (Move & adjust some `!`-adjacent tests)
 - #148929 (ignore `build-rust-analyzer` even if it's a symlink)

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

Author: bors

.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 renamed to 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);