Auto merge of #107318 - matthiaskrgr:rollup-776kd81, r=matthiaskrgr

Rollup of 9 pull requests

Successful merges:

 - #97373 (impl DispatchFromDyn for Cell and UnsafeCell)
 - #106625 (Remove backwards compat for LLVM 12 coverage format)
 - #106779 (Avoid __cxa_thread_atexit_impl on Emscripten)
 - #106811 (Append .dwp to the binary filename instead of replacing the existing extension.)
 - #106836 (Remove optimistic spinning from `mpsc::SyncSender`)
 - #106946 (implement Hash for proc_macro::LineColumn)
 - #107074 (remove unnecessary check for opaque types)
 - #107287 (Improve fn pointer notes)
 - #107304 (Use `can_eq` to compare types for default assoc type error)

Failed merges:

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

Author: bors

compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs

@@ -1,6 +1,5 @@
 use crate::common::CodegenCx;
 use crate::coverageinfo;
-use crate::errors::InstrumentCoverageRequiresLLVM12;
 use crate::llvm;
 
 use llvm::coverageinfo::CounterMappingRegion;
@@ -19,8 +18,8 @@ use std::ffi::CString;
 
 /// Generates and exports the Coverage Map.
 ///
-/// 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
+/// Rust Coverage Map generation supports LLVM Coverage Mapping Format version
+/// 6 (zero-based encoded as 5), 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.
@@ -33,13 +32,10 @@ use std::ffi::CString;
 pub fn finalize(cx: &CodegenCx<'_, '_>) {
     let tcx = cx.tcx;
 
-    // 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.
+    // Ensure the installed version of LLVM supports Coverage Map Version 6
+    // (encoded as a zero-based value: 5), which was introduced with LLVM 13.
     let version = coverageinfo::mapping_version();
-    if version < 4 {
-        tcx.sess.emit_fatal(InstrumentCoverageRequiresLLVM12);
-    }
+    assert_eq!(version, 5, "The `CoverageMappingVersion` exposed by `llvm-wrapper` is out of sync");
 
     debug!("Generating coverage map for CodegenUnit: `{}`", cx.codegen_unit.name());
 
@@ -61,7 +57,7 @@ pub fn finalize(cx: &CodegenCx<'_, '_>) {
         return;
     }
 
-    let mut mapgen = CoverageMapGenerator::new(tcx, version);
+    let mut mapgen = CoverageMapGenerator::new(tcx);
 
     // Encode coverage mappings and generate function records
     let mut function_data = Vec::new();
@@ -124,25 +120,18 @@ struct CoverageMapGenerator {
 }
 
 impl CoverageMapGenerator {
-    fn new(tcx: TyCtxt<'_>, version: u32) -> Self {
+    fn new(tcx: TyCtxt<'_>) -> 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 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);
-        }
+        // 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 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 }
     }
 

compiler/rustc_codegen_llvm/src/errors.rs

@@ -39,10 +39,6 @@ pub(crate) struct ErrorCreatingImportLibrary<'a> {
     pub error: String,
 }
 
-#[derive(Diagnostic)]
-#[diag(codegen_llvm_instrument_coverage_requires_llvm_12)]
-pub(crate) struct InstrumentCoverageRequiresLLVM12;
-
 #[derive(Diagnostic)]
 #[diag(codegen_llvm_symbol_already_defined)]
 pub(crate) struct SymbolAlreadyDefined<'a> {

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -599,7 +599,8 @@ fn link_dwarf_object<'a>(
     cg_results: &CodegenResults,
     executable_out_filename: &Path,
 ) {
-    let dwp_out_filename = executable_out_filename.with_extension("dwp");
+    let mut dwp_out_filename = executable_out_filename.to_path_buf().into_os_string();
+    dwp_out_filename.push(".dwp");
     debug!(?dwp_out_filename, ?executable_out_filename);
 
     #[derive(Default)]

compiler/rustc_const_eval/src/transform/validate.rs

@@ -13,7 +13,7 @@ use rustc_middle::mir::{
     ProjectionElem, RetagKind, RuntimePhase, Rvalue, SourceScope, Statement, StatementKind,
     Terminator, TerminatorKind, UnOp, START_BLOCK,
 };
-use rustc_middle::ty::{self, InstanceDef, ParamEnv, Ty, TyCtxt, TypeVisitable};
+use rustc_middle::ty::{self, InstanceDef, ParamEnv, Ty, TyCtxt};
 use rustc_mir_dataflow::impls::MaybeStorageLive;
 use rustc_mir_dataflow::storage::always_storage_live_locals;
 use rustc_mir_dataflow::{Analysis, ResultsCursor};
@@ -230,11 +230,6 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
             // Equal types, all is good.
             return true;
         }
-        // Normalization reveals opaque types, but we may be validating MIR while computing
-        // said opaque types, causing cycles.
-        if (src, dest).has_opaque_types() {
-            return true;
-        }
 
         crate::util::is_subtype(self.tcx, self.param_env, src, dest)
     }

compiler/rustc_error_messages/locales/en-US/codegen_llvm.ftl

@@ -11,9 +11,6 @@ codegen_llvm_unknown_ctarget_feature_prefix =
 codegen_llvm_error_creating_import_library =
     Error creating import library for {$lib_name}: {$error}
 
-codegen_llvm_instrument_coverage_requires_llvm_12 =
-    rustc option `-C instrument-coverage` requires LLVM 12 or higher.
-
 codegen_llvm_symbol_already_defined =
     symbol `{$symbol_name}` is already defined
 

compiler/rustc_infer/src/infer/error_reporting/mod.rs

@@ -79,6 +79,7 @@ use std::path::PathBuf;
 use std::{cmp, fmt, iter};
 
 mod note;
+mod note_and_explain;
 mod suggest;
 
 pub(crate) mod need_type_info;
@@ -1846,7 +1847,8 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
         }
 
         self.check_and_note_conflicting_crates(diag, terr);
-        self.tcx.note_and_explain_type_err(diag, terr, cause, span, cause.body_id.to_def_id());
+
+        self.note_and_explain_type_err(diag, terr, cause, span, cause.body_id.to_def_id());
 
         if let Some(ValuePairs::PolyTraitRefs(exp_found)) = values
             && let ty::Closure(def_id, _) = exp_found.expected.skip_binder().self_ty().kind()