Rollup of 6 pull requests

compiler/rustc_borrowck/src/diagnostics/mod.rs

@@ -738,15 +738,13 @@ impl BorrowedContentSource<'tcx> {
             BorrowedContentSource::DerefRawPointer => "a raw pointer".to_string(),
             BorrowedContentSource::DerefSharedRef => "a shared reference".to_string(),
             BorrowedContentSource::DerefMutableRef => "a mutable reference".to_string(),
-            BorrowedContentSource::OverloadedDeref(ty) => match ty.kind() {
-                ty::Adt(def, _) if tcx.is_diagnostic_item(sym::Rc, def.did) => {
-                    "an `Rc`".to_string()
-                }
-                ty::Adt(def, _) if tcx.is_diagnostic_item(sym::Arc, def.did) => {
-                    "an `Arc`".to_string()
-                }
-                _ => format!("dereference of `{}`", ty),
-            },
+            BorrowedContentSource::OverloadedDeref(ty) => ty
+                .ty_adt_def()
+                .and_then(|adt| match tcx.get_diagnostic_name(adt.did)? {
+                    name @ (sym::Rc | sym::Arc) => Some(format!("an `{}`", name)),
+                    _ => None,
+                })
+                .unwrap_or_else(|| format!("dereference of `{}`", ty)),
             BorrowedContentSource::OverloadedIndex(ty) => format!("index of `{}`", ty),
         }
     }
@@ -770,15 +768,13 @@ impl BorrowedContentSource<'tcx> {
             BorrowedContentSource::DerefMutableRef => {
                 bug!("describe_for_immutable_place: DerefMutableRef isn't immutable")
             }
-            BorrowedContentSource::OverloadedDeref(ty) => match ty.kind() {
-                ty::Adt(def, _) if tcx.is_diagnostic_item(sym::Rc, def.did) => {
-                    "an `Rc`".to_string()
-                }
-                ty::Adt(def, _) if tcx.is_diagnostic_item(sym::Arc, def.did) => {
-                    "an `Arc`".to_string()
-                }
-                _ => format!("a dereference of `{}`", ty),
-            },
+            BorrowedContentSource::OverloadedDeref(ty) => ty
+                .ty_adt_def()
+                .and_then(|adt| match tcx.get_diagnostic_name(adt.did)? {
+                    name @ (sym::Rc | sym::Arc) => Some(format!("an `{}`", name)),
+                    _ => None,
+                })
+                .unwrap_or_else(|| format!("dereference of `{}`", ty)),
             BorrowedContentSource::OverloadedIndex(ty) => format!("an index of `{}`", ty),
         }
     }
@@ -960,8 +956,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                         _ => None,
                     });
                 let is_option_or_result = parent_self_ty.map_or(false, |def_id| {
-                    tcx.is_diagnostic_item(sym::Option, def_id)
-                        || tcx.is_diagnostic_item(sym::Result, def_id)
+                    matches!(tcx.get_diagnostic_name(def_id), Some(sym::Option | sym::Result))
                 });
                 FnSelfUseKind::Normal { self_arg, implicit_into_iter, is_option_or_result }
             });

compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs

@@ -9,6 +9,7 @@ use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexSet};
 use rustc_hir::def_id::{DefId, DefIdSet};
 use rustc_llvm::RustString;
 use rustc_middle::mir::coverage::CodeRegion;
+use rustc_middle::ty::TyCtxt;
 use rustc_span::Symbol;
 
 use std::ffi::CString;
@@ -17,10 +18,11 @@ use tracing::debug;
 
 /// Generates and exports the Coverage Map.
 ///
-/// This Coverage Map complies with Coverage Mapping Format version 4 (zero-based encoded as 3),
-/// as defined at [LLVM Code Coverage Mapping Format](https://github.com/rust-lang/llvm-project/blob/rustc/11.0-2020-10-12/llvm/docs/CoverageMappingFormat.rst#llvm-code-coverage-mapping-format)
-/// and published in Rust's November 2020 fork of LLVM. This version is supported by the LLVM
-/// coverage tools (`llvm-profdata` and `llvm-cov`) bundled with Rust's fork of LLVM.
+/// Rust Coverage Map generation supports LLVM Coverage Mapping Format versions
+/// 5 (LLVM 12, only) and 6 (zero-based encoded as 4 and 5, respectively), as defined at
+/// [LLVM Code Coverage Mapping Format](https://github.com/rust-lang/llvm-project/blob/rustc/13.0-2021-09-30/llvm/docs/CoverageMappingFormat.rst#llvm-code-coverage-mapping-format).
+/// These versions are supported by the LLVM coverage tools (`llvm-profdata` and `llvm-cov`)
+/// bundled with Rust's fork of LLVM.
 ///
 /// Consequently, Rust's bundled version of Clang also generates Coverage Maps compliant with
 /// the same version. Clang's implementation of Coverage Map generation was referenced when
@@ -30,11 +32,12 @@ use tracing::debug;
 pub fn finalize<'ll, 'tcx>(cx: &CodegenCx<'ll, 'tcx>) {
     let tcx = cx.tcx;
 
-    // Ensure LLVM supports Coverage Map Version 4 (encoded as a zero-based value: 3).
-    // If not, the LLVM Version must be less than 11.
+    // Ensure the installed version of LLVM supports at least Coverage Map
+    // Version 5 (encoded as a zero-based value: 4), which was introduced with
+    // LLVM 12.
     let version = coverageinfo::mapping_version();
-    if version != 3 {
-        tcx.sess.fatal("rustc option `-Z instrument-coverage` requires LLVM 11 or higher.");
+    if version < 4 {
+        tcx.sess.fatal("rustc option `-Z instrument-coverage` requires LLVM 12 or higher.");
     }
 
     debug!("Generating coverage map for CodegenUnit: `{}`", cx.codegen_unit.name());
@@ -57,7 +60,7 @@ pub fn finalize<'ll, 'tcx>(cx: &CodegenCx<'ll, 'tcx>) {
         return;
     }
 
-    let mut mapgen = CoverageMapGenerator::new();
+    let mut mapgen = CoverageMapGenerator::new(tcx, version);
 
     // Encode coverage mappings and generate function records
     let mut function_data = Vec::new();
@@ -112,8 +115,26 @@ struct CoverageMapGenerator {
 }
 
 impl CoverageMapGenerator {
-    fn new() -> Self {
-        Self { filenames: FxIndexSet::default() }
+    fn new(tcx: TyCtxt<'_>, version: u32) -> Self {
+        let mut filenames = FxIndexSet::default();
+        if version >= 5 {
+            // LLVM Coverage Mapping Format version 6 (zero-based encoded as 5)
+            // requires setting the first filename to the compilation directory.
+            // Since rustc generates coverage maps with relative paths, the
+            // compilation directory can be combined with the the relative paths
+            // to get absolute paths, if needed.
+            let working_dir = tcx
+                .sess
+                .opts
+                .working_dir
+                .remapped_path_if_available()
+                .to_string_lossy()
+                .to_string();
+            let c_filename =
+                CString::new(working_dir).expect("null error converting filename to C string");
+            filenames.insert(c_filename);
+        }
+        Self { filenames }
     }
 
     /// Using the `expressions` and `counter_regions` collected for the current function, generate

compiler/rustc_codegen_llvm/src/llvm/ffi.rs

@@ -685,7 +685,7 @@ pub type InlineAsmDiagHandlerTy = unsafe extern "C" fn(&SMDiagnostic, *const c_v
 pub mod coverageinfo {
     use super::coverage_map;
 
-    /// Aligns with [llvm::coverage::CounterMappingRegion::RegionKind](https://github.com/rust-lang/llvm-project/blob/rustc/11.0-2020-10-12/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h#L206-L222)
+    /// Aligns with [llvm::coverage::CounterMappingRegion::RegionKind](https://github.com/rust-lang/llvm-project/blob/rustc/13.0-2021-09-30/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h#L209-L230)
     #[derive(Copy, Clone, Debug)]
     #[repr(C)]
     pub enum RegionKind {
@@ -704,11 +704,16 @@ pub mod coverageinfo {
         /// A GapRegion is like a CodeRegion, but its count is only set as the
         /// line execution count when its the only region in the line.
         GapRegion = 3,
+
+        /// A BranchRegion represents leaf-level boolean expressions and is
+        /// associated with two counters, each representing the number of times the
+        /// expression evaluates to true or false.
+        BranchRegion = 4,
     }
 
     /// This struct provides LLVM's representation of a "CoverageMappingRegion", encoded into the
     /// coverage map, in accordance with the
-    /// [LLVM Code Coverage Mapping Format](https://github.com/rust-lang/llvm-project/blob/rustc/11.0-2020-10-12/llvm/docs/CoverageMappingFormat.rst#llvm-code-coverage-mapping-format).
+    /// [LLVM Code Coverage Mapping Format](https://github.com/rust-lang/llvm-project/blob/rustc/13.0-2021-09-30/llvm/docs/CoverageMappingFormat.rst#llvm-code-coverage-mapping-format).
     /// The struct composes fields representing the `Counter` type and value(s) (injected counter
     /// ID, or expression type and operands), the source file (an indirect index into a "filenames
     /// array", encoded separately), and source location (start and end positions of the represented
@@ -721,6 +726,10 @@ pub mod coverageinfo {
         /// The counter type and type-dependent counter data, if any.
         counter: coverage_map::Counter,
 
+        /// If the `RegionKind` is a `BranchRegion`, this represents the counter
+        /// for the false branch of the region.
+        false_counter: coverage_map::Counter,
+
         /// An indirect reference to the source filename. In the LLVM Coverage Mapping Format, the
         /// file_id is an index into a function-specific `virtual_file_mapping` array of indexes
         /// that, in turn, are used to look up the filename for this region.
@@ -758,6 +767,7 @@ pub mod coverageinfo {
         ) -> Self {
             Self {
                 counter,
+                false_counter: coverage_map::Counter::zero(),
                 file_id,
                 expanded_file_id: 0,
                 start_line,
@@ -768,6 +778,31 @@ pub mod coverageinfo {
             }
         }
 
+        // This function might be used in the future; the LLVM API is still evolving, as is coverage
+        // support.
+        #[allow(dead_code)]
+        crate fn branch_region(
+            counter: coverage_map::Counter,
+            false_counter: coverage_map::Counter,
+            file_id: u32,
+            start_line: u32,
+            start_col: u32,
+            end_line: u32,
+            end_col: u32,
+        ) -> Self {
+            Self {
+                counter,
+                false_counter,
+                file_id,
+                expanded_file_id: 0,
+                start_line,
+                start_col,
+                end_line,
+                end_col,
+                kind: RegionKind::BranchRegion,
+            }
+        }
+
         // This function might be used in the future; the LLVM API is still evolving, as is coverage
         // support.
         #[allow(dead_code)]
@@ -781,6 +816,7 @@ pub mod coverageinfo {
         ) -> Self {
             Self {
                 counter: coverage_map::Counter::zero(),
+                false_counter: coverage_map::Counter::zero(),
                 file_id,
                 expanded_file_id,
                 start_line,
@@ -803,6 +839,7 @@ pub mod coverageinfo {
         ) -> Self {
             Self {
                 counter: coverage_map::Counter::zero(),
+                false_counter: coverage_map::Counter::zero(),
                 file_id,
                 expanded_file_id: 0,
                 start_line,
@@ -826,6 +863,7 @@ pub mod coverageinfo {
         ) -> Self {
             Self {
                 counter,
+                false_counter: coverage_map::Counter::zero(),
                 file_id,
                 expanded_file_id: 0,
                 start_line,

compiler/rustc_codegen_ssa/src/coverageinfo/ffi.rs

@@ -1,6 +1,6 @@
 use rustc_middle::mir::coverage::{CounterValueReference, MappedExpressionIndex};
 
-/// Aligns with [llvm::coverage::Counter::CounterKind](https://github.com/rust-lang/llvm-project/blob/rustc/11.0-2020-10-12/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h#L206-L222)
+/// Aligns with [llvm::coverage::Counter::CounterKind](https://github.com/rust-lang/llvm-project/blob/rustc/13.0-2021-09-30/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h#L95)
 #[derive(Copy, Clone, Debug)]
 #[repr(C)]
 pub enum CounterKind {
@@ -17,7 +17,7 @@ pub enum CounterKind {
 ///     `instrprof.increment()`)
 ///   * For `CounterKind::Expression`, `id` is the index into the coverage map's array of
 ///     counter expressions.
-/// Aligns with [llvm::coverage::Counter](https://github.com/rust-lang/llvm-project/blob/rustc/11.0-2020-10-12/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h#L99-L100)
+/// Aligns with [llvm::coverage::Counter](https://github.com/rust-lang/llvm-project/blob/rustc/13.0-2021-09-30/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h#L102-L103)
 /// Important: The Rust struct layout (order and types of fields) must match its C++ counterpart.
 #[derive(Copy, Clone, Debug)]
 #[repr(C)]
@@ -59,15 +59,15 @@ impl Counter {
     }
 }
 
-/// Aligns with [llvm::coverage::CounterExpression::ExprKind](https://github.com/rust-lang/llvm-project/blob/rustc/11.0-2020-10-12/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h#L147)
+/// Aligns with [llvm::coverage::CounterExpression::ExprKind](https://github.com/rust-lang/llvm-project/blob/rustc/13.0-2021-09-30/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h#L150)
 #[derive(Copy, Clone, Debug)]
 #[repr(C)]
 pub enum ExprKind {
     Subtract = 0,
     Add = 1,
 }
 
-/// Aligns with [llvm::coverage::CounterExpression](https://github.com/rust-lang/llvm-project/blob/rustc/11.0-2020-10-12/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h#L148-L149)
+/// Aligns with [llvm::coverage::CounterExpression](https://github.com/rust-lang/llvm-project/blob/rustc/13.0-2021-09-30/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h#L151-L152)
 /// Important: The Rust struct layout (order and types of fields) must match its C++
 /// counterpart.
 #[derive(Copy, Clone, Debug)]

compiler/rustc_lint/src/enum_intrinsics_non_enums.rs

@@ -91,16 +91,14 @@ fn enforce_mem_variant_count(cx: &LateContext<'_>, func_expr: &hir::Expr<'_>, sp
 
 impl<'tcx> LateLintPass<'tcx> for EnumIntrinsicsNonEnums {
     fn check_expr(&mut self, cx: &LateContext<'_>, expr: &hir::Expr<'_>) {
-        if let hir::ExprKind::Call(ref func, ref args) = expr.kind {
-            if let hir::ExprKind::Path(ref qpath) = func.kind {
-                if let Some(def_id) = cx.qpath_res(qpath, func.hir_id).opt_def_id() {
-                    if cx.tcx.is_diagnostic_item(sym::mem_discriminant, def_id) {
-                        enforce_mem_discriminant(cx, func, expr.span, args[0].span);
-                    } else if cx.tcx.is_diagnostic_item(sym::mem_variant_count, def_id) {
-                        enforce_mem_variant_count(cx, func, expr.span);
-                    }
-                }
-            }
+        let hir::ExprKind::Call(func, args) = &expr.kind else { return };
+        let hir::ExprKind::Path(qpath) = &func.kind else { return };
+        let Some(def_id) = cx.qpath_res(qpath, func.hir_id).opt_def_id() else { return };
+        let Some(name) = cx.tcx.get_diagnostic_name(def_id) else { return };
+        match name {
+            sym::mem_discriminant => enforce_mem_discriminant(cx, func, expr.span, args[0].span),
+            sym::mem_variant_count => enforce_mem_variant_count(cx, func, expr.span),
+            _ => {}
         }
     }
 }

compiler/rustc_lint/src/lib.rs

@@ -33,6 +33,7 @@
 #![cfg_attr(bootstrap, feature(format_args_capture))]
 #![feature(iter_order_by)]
 #![feature(iter_zip)]
+#![feature(let_else)]
 #![feature(never_type)]
 #![feature(nll)]
 #![feature(control_flow_enum)]

compiler/rustc_lint/src/non_fmt_panic.rs

@@ -309,14 +309,21 @@ fn panic_call<'tcx>(cx: &LateContext<'tcx>, f: &'tcx hir::Expr<'tcx>) -> (Span,
     // Unwrap more levels of macro expansion, as panic_2015!()
     // was likely expanded from panic!() and possibly from
     // [debug_]assert!().
-    for &i in
-        &[sym::std_panic_macro, sym::core_panic_macro, sym::assert_macro, sym::debug_assert_macro]
-    {
+    loop {
         let parent = expn.call_site.ctxt().outer_expn_data();
-        if parent.macro_def_id.map_or(false, |id| cx.tcx.is_diagnostic_item(i, id)) {
-            expn = parent;
-            panic_macro = i;
+        let Some(id) = parent.macro_def_id else { break };
+        let Some(name) = cx.tcx.get_diagnostic_name(id) else { break };
+        if !matches!(
+            name,
+            sym::core_panic_macro
+                | sym::std_panic_macro
+                | sym::assert_macro
+                | sym::debug_assert_macro
+        ) {
+            break;
         }
+        expn = parent;
+        panic_macro = name;
     }
 
     let macro_symbol =