Rollup of 14 pull requests

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_attr_parsing/src/attributes/cfg.rs

@@ -82,7 +82,8 @@ pub fn parse_cfg_entry<S: Stage>(
                 }
             },
             a @ (ArgParser::NoArgs | ArgParser::NameValue(_)) => {
-                let Some(name) = meta.path().word_sym() else {
+                let Some(name) = meta.path().word_sym().filter(|s| !s.is_path_segment_keyword())
+                else {
                     return Err(cx.expected_identifier(meta.path().span()));
                 };
                 parse_name_value(name, meta.path().span(), a.name_value(), meta.span(), cx)?
@@ -158,7 +159,7 @@ fn parse_cfg_entry_target<S: Stage>(
         };
 
         // Then, parse it as a name-value item
-        let Some(name) = sub_item.path().word_sym() else {
+        let Some(name) = sub_item.path().word_sym().filter(|s| !s.is_path_segment_keyword()) else {
             return Err(cx.expected_identifier(sub_item.path().span()));
         };
         let name = Symbol::intern(&format!("target_{name}"));

compiler/rustc_attr_parsing/src/attributes/cfg_old.rs

@@ -220,7 +220,10 @@ pub fn eval_condition(
                 }
             }
         }
-        MetaItemKind::Word | MetaItemKind::NameValue(..) if cfg.path.segments.len() != 1 => {
+        MetaItemKind::Word | MetaItemKind::NameValue(..)
+            if cfg.path.segments.len() != 1
+                || cfg.path.segments[0].ident.is_path_segment_keyword() =>
+        {
             dcx.emit_err(session_diagnostics::CfgPredicateIdentifier { span: cfg.path.span });
             true
         }

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_errors/src/emitter.rs

@@ -532,30 +532,24 @@ impl Emitter for HumanEmitter {
     }
 }
 
-/// An emitter that does nothing when emitting a non-fatal diagnostic.
-/// Fatal diagnostics are forwarded to `fatal_emitter` to avoid silent
-/// failures of rustc, as witnessed e.g. in issue #89358.
-pub struct FatalOnlyEmitter {
-    pub fatal_emitter: Box<dyn Emitter + DynSend>,
-    pub fatal_note: Option<String>,
+/// An emitter that adds a note to each diagnostic.
+pub struct EmitterWithNote {
+    pub emitter: Box<dyn Emitter + DynSend>,
+    pub note: String,
 }
 
-impl Emitter for FatalOnlyEmitter {
+impl Emitter for EmitterWithNote {
     fn source_map(&self) -> Option<&SourceMap> {
         None
     }
 
     fn emit_diagnostic(&mut self, mut diag: DiagInner, registry: &Registry) {
-        if diag.level == Level::Fatal {
-            if let Some(fatal_note) = &self.fatal_note {
-                diag.sub(Level::Note, fatal_note.clone(), MultiSpan::new());
-            }
-            self.fatal_emitter.emit_diagnostic(diag, registry);
-        }
+        diag.sub(Level::Note, self.note.clone(), MultiSpan::new());
+        self.emitter.emit_diagnostic(diag, registry);
     }
 
     fn translator(&self) -> &Translator {
-        self.fatal_emitter.translator()
+        self.emitter.translator()
     }
 }
 

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_interface/src/interface.rs

@@ -15,6 +15,7 @@ use rustc_middle::ty::CurrentGcx;
 use rustc_middle::util::Providers;
 use rustc_parse::lexer::StripTokens;
 use rustc_parse::new_parser_from_source_str;
+use rustc_parse::parser::Recovery;
 use rustc_parse::parser::attr::AllowLeadingUnsafe;
 use rustc_query_impl::QueryCtxt;
 use rustc_query_system::query::print_query_stack;
@@ -52,46 +53,56 @@ pub struct Compiler {
 pub(crate) fn parse_cfg(dcx: DiagCtxtHandle<'_>, cfgs: Vec<String>) -> Cfg {
     cfgs.into_iter()
         .map(|s| {
-            let psess = ParseSess::with_fatal_emitter(
+            let psess = ParseSess::emitter_with_note(
                 vec![crate::DEFAULT_LOCALE_RESOURCE, rustc_parse::DEFAULT_LOCALE_RESOURCE],
-                format!("this error occurred on the command line: `--cfg={s}`"),
+                format!("this occurred on the command line: `--cfg={s}`"),
             );
             let filename = FileName::cfg_spec_source_code(&s);
 
             macro_rules! error {
                 ($reason: expr) => {
                     #[allow(rustc::untranslatable_diagnostic)]
                     #[allow(rustc::diagnostic_outside_of_impl)]
-                    dcx.fatal(format!(
-                        concat!("invalid `--cfg` argument: `{}` (", $reason, ")"),
-                        s
-                    ));
+                    dcx.fatal(format!("invalid `--cfg` argument: `{s}` ({})", $reason));
                 };
             }
 
             match new_parser_from_source_str(&psess, filename, s.to_string(), StripTokens::Nothing)
             {
-                Ok(mut parser) => match parser.parse_meta_item(AllowLeadingUnsafe::No) {
-                    Ok(meta_item) if parser.token == token::Eof => {
-                        if meta_item.path.segments.len() != 1 {
-                            error!("argument key must be an identifier");
-                        }
-                        match &meta_item.kind {
-                            MetaItemKind::List(..) => {}
-                            MetaItemKind::NameValue(lit) if !lit.kind.is_str() => {
-                                error!("argument value must be a string");
+                Ok(mut parser) => {
+                    parser = parser.recovery(Recovery::Forbidden);
+                    match parser.parse_meta_item(AllowLeadingUnsafe::No) {
+                        Ok(meta_item)
+                            if parser.token == token::Eof
+                                && parser.dcx().has_errors().is_none() =>
+                        {
+                            if meta_item.path.segments.len() != 1 {
+                                error!("argument key must be an identifier");
                             }
-                            MetaItemKind::NameValue(..) | MetaItemKind::Word => {
-                                let ident = meta_item.ident().expect("multi-segment cfg key");
-                                return (ident.name, meta_item.value_str());
+                            match &meta_item.kind {
+                                MetaItemKind::List(..) => {}
+                                MetaItemKind::NameValue(lit) if !lit.kind.is_str() => {
+                                    error!("argument value must be a string");
+                                }
+                                MetaItemKind::NameValue(..) | MetaItemKind::Word => {
+                                    let ident = meta_item.ident().expect("multi-segment cfg key");
+
+                                    if ident.is_path_segment_keyword() {
+                                        error!(
+                                            "malformed `cfg` input, expected a valid identifier"
+                                        );
+                                    }
+
+                                    return (ident.name, meta_item.value_str());
+                                }
                             }
                         }
+                        Ok(..) => {}
+                        Err(err) => err.cancel(),
                     }
-                    Ok(..) => {}
-                    Err(err) => err.cancel(),
-                },
+                }
                 Err(errs) => errs.into_iter().for_each(|err| err.cancel()),
-            }
+            };
 
             // If the user tried to use a key="value" flag, but is missing the quotes, provide
             // a hint about how to resolve this.
@@ -116,9 +127,9 @@ pub(crate) fn parse_check_cfg(dcx: DiagCtxtHandle<'_>, specs: Vec<String>) -> Ch
     let mut check_cfg = CheckCfg { exhaustive_names, exhaustive_values, ..CheckCfg::default() };
 
     for s in specs {
-        let psess = ParseSess::with_fatal_emitter(
+        let psess = ParseSess::emitter_with_note(
             vec![crate::DEFAULT_LOCALE_RESOURCE, rustc_parse::DEFAULT_LOCALE_RESOURCE],
-            format!("this error occurred on the command line: `--check-cfg={s}`"),
+            format!("this occurred on the command line: `--check-cfg={s}`"),
         );
         let filename = FileName::cfg_spec_source_code(&s);
 
@@ -171,15 +182,17 @@ pub(crate) fn parse_check_cfg(dcx: DiagCtxtHandle<'_>, specs: Vec<String>) -> Ch
         let mut parser =
             match new_parser_from_source_str(&psess, filename, s.to_string(), StripTokens::Nothing)
             {
-                Ok(parser) => parser,
+                Ok(parser) => parser.recovery(Recovery::Forbidden),
                 Err(errs) => {
                     errs.into_iter().for_each(|err| err.cancel());
                     expected_error();
                 }
             };
 
         let meta_item = match parser.parse_meta_item(AllowLeadingUnsafe::No) {
-            Ok(meta_item) if parser.token == token::Eof => meta_item,
+            Ok(meta_item) if parser.token == token::Eof && parser.dcx().has_errors().is_none() => {
+                meta_item
+            }
             Ok(..) => expected_error(),
             Err(err) => {
                 err.cancel();
@@ -209,6 +222,11 @@ pub(crate) fn parse_check_cfg(dcx: DiagCtxtHandle<'_>, specs: Vec<String>) -> Ch
                 if values_specified {
                     error!("`cfg()` names cannot be after values");
                 }
+
+                if ident.is_path_segment_keyword() {
+                    error!("malformed `cfg` input, expected a valid identifier");
+                }
+
                 names.push(ident);
             } else if let Some(boolean) = arg.boolean_literal() {
                 if values_specified {

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 }
 }