Auto merge of rust-lang#134282 - matthiaskrgr:rollup-txnn8yz, r=matthiaskrgr

Rollup of 7 pull requests

Successful merges:

 - rust-lang#132150 (Fix powerpc64 big-endian FreeBSD ABI)
 - rust-lang#133633 (don't show the full linker args unless `--verbose` is passed)
 - rust-lang#133942 (Clarify how to use `black_box()`)
 - rust-lang#134081 (Try to evaluate constants in legacy mangling)
 - rust-lang#134192 (Remove `Lexer`'s dependency on `Parser`.)
 - rust-lang#134208 (coverage: Tidy up creation of covmap and covfun records)
 - rust-lang#134211 (On Neutrino QNX, reduce the need to set archiver via environment variables)

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

Author: bors

compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs

@@ -75,10 +75,10 @@ pub(crate) fn finalize(cx: &CodegenCx<'_, '_>) {
 
     // Encode all filenames referenced by coverage mappings in this CGU.
     let filenames_buffer = global_file_table.make_filenames_buffer(tcx);
-
-    let filenames_size = filenames_buffer.len();
-    let filenames_val = cx.const_bytes(&filenames_buffer);
-    let filenames_ref = llvm_cov::hash_bytes(&filenames_buffer);
+    // The `llvm-cov` tool uses this hash to associate each covfun record with
+    // its corresponding filenames table, since the final binary will typically
+    // contain multiple covmap records from different compilation units.
+    let filenames_hash = llvm_cov::hash_bytes(&filenames_buffer);
 
     let mut unused_function_names = Vec::new();
 
@@ -101,7 +101,7 @@ pub(crate) fn finalize(cx: &CodegenCx<'_, '_>) {
     for covfun in &covfun_records {
         unused_function_names.extend(covfun.mangled_function_name_if_unused());
 
-        covfun::generate_covfun_record(cx, filenames_ref, covfun)
+        covfun::generate_covfun_record(cx, filenames_hash, covfun)
     }
 
     // For unused functions, we need to take their mangled names and store them
@@ -126,7 +126,7 @@ pub(crate) fn finalize(cx: &CodegenCx<'_, '_>) {
     // Generate the coverage map header, which contains the filenames used by
     // this CGU's coverage mappings, and store it in a well-known global.
     // (This is skipped if we returned early due to having no covfun records.)
-    generate_covmap_record(cx, covmap_version, filenames_size, filenames_val);
+    generate_covmap_record(cx, covmap_version, &filenames_buffer);
 }
 
 /// Maps "global" (per-CGU) file ID numbers to their underlying filenames.
@@ -225,38 +225,35 @@ fn span_file_name(tcx: TyCtxt<'_>, span: Span) -> Symbol {
 /// Generates the contents of the covmap record for this CGU, which mostly
 /// consists of a header and a list of filenames. The record is then stored
 /// as a global variable in the `__llvm_covmap` section.
-fn generate_covmap_record<'ll>(
-    cx: &CodegenCx<'ll, '_>,
-    version: u32,
-    filenames_size: usize,
-    filenames_val: &'ll llvm::Value,
-) {
-    debug!("cov map: filenames_size = {}, 0-based version = {}", filenames_size, version);
-
-    // Create the coverage data header (Note, fields 0 and 2 are now always zero,
-    // as of `llvm::coverage::CovMapVersion::Version4`.)
-    let zero_was_n_records_val = cx.const_u32(0);
-    let filenames_size_val = cx.const_u32(filenames_size as u32);
-    let zero_was_coverage_size_val = cx.const_u32(0);
-    let version_val = cx.const_u32(version);
-    let cov_data_header_val = cx.const_struct(
-        &[zero_was_n_records_val, filenames_size_val, zero_was_coverage_size_val, version_val],
-        /*packed=*/ false,
+fn generate_covmap_record<'ll>(cx: &CodegenCx<'ll, '_>, version: u32, filenames_buffer: &[u8]) {
+    // A covmap record consists of four target-endian u32 values, followed by
+    // the encoded filenames table. Two of the header fields are unused in
+    // modern versions of the LLVM coverage mapping format, and are always 0.
+    // <https://llvm.org/docs/CoverageMappingFormat.html#llvm-ir-representation>
+    // See also `src/llvm-project/clang/lib/CodeGen/CoverageMappingGen.cpp`.
+    let covmap_header = cx.const_struct(
+        &[
+            cx.const_u32(0), // (unused)
+            cx.const_u32(filenames_buffer.len() as u32),
+            cx.const_u32(0), // (unused)
+            cx.const_u32(version),
+        ],
+        /* packed */ false,
     );
-
-    // Create the complete LLVM coverage data value to add to the LLVM IR
-    let covmap_data =
-        cx.const_struct(&[cov_data_header_val, filenames_val], /*packed=*/ false);
-
-    let llglobal = llvm::add_global(cx.llmod, cx.val_ty(covmap_data), &llvm_cov::covmap_var_name());
-    llvm::set_initializer(llglobal, covmap_data);
-    llvm::set_global_constant(llglobal, true);
-    llvm::set_linkage(llglobal, llvm::Linkage::PrivateLinkage);
-    llvm::set_section(llglobal, &llvm_cov::covmap_section_name(cx.llmod));
+    let covmap_record = cx
+        .const_struct(&[covmap_header, cx.const_bytes(filenames_buffer)], /* packed */ false);
+
+    let covmap_global =
+        llvm::add_global(cx.llmod, cx.val_ty(covmap_record), &llvm_cov::covmap_var_name());
+    llvm::set_initializer(covmap_global, covmap_record);
+    llvm::set_global_constant(covmap_global, true);
+    llvm::set_linkage(covmap_global, llvm::Linkage::PrivateLinkage);
+    llvm::set_section(covmap_global, &llvm_cov::covmap_section_name(cx.llmod));
     // LLVM's coverage mapping format specifies 8-byte alignment for items in this section.
     // <https://llvm.org/docs/CoverageMappingFormat.html>
-    llvm::set_alignment(llglobal, Align::EIGHT);
-    cx.add_used_global(llglobal);
+    llvm::set_alignment(covmap_global, Align::EIGHT);
+
+    cx.add_used_global(covmap_global);
 }
 
 /// Each CGU will normally only emit coverage metadata for the functions that it actually generates.

compiler/rustc_codegen_llvm/src/coverageinfo/mapgen/covfun.rs

@@ -136,7 +136,7 @@ fn fill_region_tables<'tcx>(
 /// as a global variable in the `__llvm_covfun` section.
 pub(crate) fn generate_covfun_record<'tcx>(
     cx: &CodegenCx<'_, 'tcx>,
-    filenames_ref: u64,
+    filenames_hash: u64,
     covfun: &CovfunRecord<'tcx>,
 ) {
     let &CovfunRecord {
@@ -155,46 +155,45 @@ pub(crate) fn generate_covfun_record<'tcx>(
         regions,
     );
 
-    // Concatenate the encoded coverage mappings
-    let coverage_mapping_size = coverage_mapping_buffer.len();
-    let coverage_mapping_val = cx.const_bytes(&coverage_mapping_buffer);
-
+    // A covfun record consists of four target-endian integers, followed by the
+    // encoded mapping data in bytes. Note that the length field is 32 bits.
+    // <https://llvm.org/docs/CoverageMappingFormat.html#llvm-ir-representation>
+    // See also `src/llvm-project/clang/lib/CodeGen/CoverageMappingGen.cpp` and
+    // `COVMAP_V3` in `src/llvm-project/llvm/include/llvm/ProfileData/InstrProfData.inc`.
     let func_name_hash = llvm_cov::hash_bytes(mangled_function_name.as_bytes());
-    let func_name_hash_val = cx.const_u64(func_name_hash);
-    let coverage_mapping_size_val = cx.const_u32(coverage_mapping_size as u32);
-    let source_hash_val = cx.const_u64(source_hash);
-    let filenames_ref_val = cx.const_u64(filenames_ref);
-    let func_record_val = cx.const_struct(
+    let covfun_record = cx.const_struct(
         &[
-            func_name_hash_val,
-            coverage_mapping_size_val,
-            source_hash_val,
-            filenames_ref_val,
-            coverage_mapping_val,
+            cx.const_u64(func_name_hash),
+            cx.const_u32(coverage_mapping_buffer.len() as u32),
+            cx.const_u64(source_hash),
+            cx.const_u64(filenames_hash),
+            cx.const_bytes(&coverage_mapping_buffer),
         ],
-        /*packed=*/ true,
+        // This struct needs to be packed, so that the 32-bit length field
+        // doesn't have unexpected padding.
+        true,
     );
 
     // Choose a variable name to hold this function's covfun data.
     // Functions that are used have a suffix ("u") to distinguish them from
     // unused copies of the same function (from different CGUs), so that if a
     // linker sees both it won't discard the used copy's data.
-    let func_record_var_name =
-        CString::new(format!("__covrec_{:X}{}", func_name_hash, if is_used { "u" } else { "" }))
-            .unwrap();
-    debug!("function record var name: {:?}", func_record_var_name);
-
-    let llglobal = llvm::add_global(cx.llmod, cx.val_ty(func_record_val), &func_record_var_name);
-    llvm::set_initializer(llglobal, func_record_val);
-    llvm::set_global_constant(llglobal, true);
-    llvm::set_linkage(llglobal, llvm::Linkage::LinkOnceODRLinkage);
-    llvm::set_visibility(llglobal, llvm::Visibility::Hidden);
-    llvm::set_section(llglobal, cx.covfun_section_name());
+    let u = if is_used { "u" } else { "" };
+    let covfun_var_name = CString::new(format!("__covrec_{func_name_hash:X}{u}")).unwrap();
+    debug!("function record var name: {covfun_var_name:?}");
+
+    let covfun_global = llvm::add_global(cx.llmod, cx.val_ty(covfun_record), &covfun_var_name);
+    llvm::set_initializer(covfun_global, covfun_record);
+    llvm::set_global_constant(covfun_global, true);
+    llvm::set_linkage(covfun_global, llvm::Linkage::LinkOnceODRLinkage);
+    llvm::set_visibility(covfun_global, llvm::Visibility::Hidden);
+    llvm::set_section(covfun_global, cx.covfun_section_name());
     // LLVM's coverage mapping format specifies 8-byte alignment for items in this section.
     // <https://llvm.org/docs/CoverageMappingFormat.html>
-    llvm::set_alignment(llglobal, Align::EIGHT);
+    llvm::set_alignment(covfun_global, Align::EIGHT);
     if cx.target_spec().supports_comdat() {
-        llvm::set_comdat(cx.llmod, llglobal, &func_record_var_name);
+        llvm::set_comdat(cx.llmod, covfun_global, &covfun_var_name);
     }
-    cx.add_used_global(llglobal);
+
+    cx.add_used_global(covfun_global);
 }

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -992,12 +992,12 @@ fn link_natively(
                 let mut output = prog.stderr.clone();
                 output.extend_from_slice(&prog.stdout);
                 let escaped_output = escape_linker_output(&output, flavor);
-                // FIXME: Add UI tests for this error.
                 let err = errors::LinkingFailed {
                     linker_path: &linker_path,
                     exit_status: prog.status,
-                    command: &cmd,
+                    command: cmd,
                     escaped_output,
+                    verbose: sess.opts.verbose,
                 };
                 sess.dcx().emit_err(err);
                 // If MSVC's `link.exe` was expected but the return code

compiler/rustc_codegen_ssa/src/errors.rs

@@ -1,6 +1,7 @@
 //! Errors emitted by codegen_ssa
 
 use std::borrow::Cow;
+use std::ffi::OsString;
 use std::io::Error;
 use std::num::ParseIntError;
 use std::path::{Path, PathBuf};
@@ -345,21 +346,82 @@ impl<G: EmissionGuarantee> Diagnostic<'_, G> for ThorinErrorWrapper {
 }
 
 pub(crate) struct LinkingFailed<'a> {
-    pub linker_path: &'a PathBuf,
+    pub linker_path: &'a Path,
     pub exit_status: ExitStatus,
-    pub command: &'a Command,
+    pub command: Command,
     pub escaped_output: String,
+    pub verbose: bool,
 }
 
 impl<G: EmissionGuarantee> Diagnostic<'_, G> for LinkingFailed<'_> {
-    fn into_diag(self, dcx: DiagCtxtHandle<'_>, level: Level) -> Diag<'_, G> {
+    fn into_diag(mut self, dcx: DiagCtxtHandle<'_>, level: Level) -> Diag<'_, G> {
         let mut diag = Diag::new(dcx, level, fluent::codegen_ssa_linking_failed);
         diag.arg("linker_path", format!("{}", self.linker_path.display()));
         diag.arg("exit_status", format!("{}", self.exit_status));
 
         let contains_undefined_ref = self.escaped_output.contains("undefined reference to");
 
-        diag.note(format!("{:?}", self.command)).note(self.escaped_output);
+        if self.verbose {
+            diag.note(format!("{:?}", self.command));
+        } else {
+            enum ArgGroup {
+                Regular(OsString),
+                Objects(usize),
+                Rlibs(PathBuf, Vec<OsString>),
+            }
+
+            // Omit rust object files and fold rlibs in the error by default to make linker errors a
+            // bit less verbose.
+            let orig_args = self.command.take_args();
+            let mut args: Vec<ArgGroup> = vec![];
+            for arg in orig_args {
+                if arg.as_encoded_bytes().ends_with(b".rcgu.o") {
+                    if let Some(ArgGroup::Objects(n)) = args.last_mut() {
+                        *n += 1;
+                    } else {
+                        args.push(ArgGroup::Objects(1));
+                    }
+                } else if arg.as_encoded_bytes().ends_with(b".rlib") {
+                    let rlib_path = Path::new(&arg);
+                    let dir = rlib_path.parent().unwrap();
+                    let filename = rlib_path.file_name().unwrap().to_owned();
+                    if let Some(ArgGroup::Rlibs(parent, rlibs)) = args.last_mut() {
+                        if parent == dir {
+                            rlibs.push(filename);
+                        } else {
+                            args.push(ArgGroup::Rlibs(dir.to_owned(), vec![filename]));
+                        }
+                    } else {
+                        args.push(ArgGroup::Rlibs(dir.to_owned(), vec![filename]));
+                    }
+                } else {
+                    args.push(ArgGroup::Regular(arg));
+                }
+            }
+            self.command.args(args.into_iter().map(|arg_group| match arg_group {
+                ArgGroup::Regular(arg) => arg,
+                ArgGroup::Objects(n) => OsString::from(format!("<{n} object files omitted>")),
+                ArgGroup::Rlibs(dir, rlibs) => {
+                    let mut arg = dir.into_os_string();
+                    arg.push("/{");
+                    let mut first = true;
+                    for rlib in rlibs {
+                        if !first {
+                            arg.push(",");
+                        }
+                        first = false;
+                        arg.push(rlib);
+                    }
+                    arg.push("}");
+                    arg
+                }
+            }));
+
+            diag.note(format!("{:?}", self.command));
+            diag.note("some arguments are omitted. use `--verbose` to show all linker arguments");
+        }
+
+        diag.note(self.escaped_output);
 
         // Trying to match an error from OS linkers
         // which by now we have no way to translate.

compiler/rustc_parse/src/lexer/mod.rs

@@ -69,24 +69,30 @@ pub(crate) fn lex_token_trees<'psess, 'src>(
         token: Token::dummy(),
         diag_info: TokenTreeDiagInfo::default(),
     };
-    let (_open_spacing, stream, res) = lexer.lex_token_trees(/* is_delimited */ false);
-    let unmatched_delims = lexer.diag_info.unmatched_delims;
-
-    if res.is_ok() && unmatched_delims.is_empty() {
-        Ok(stream)
-    } else {
-        // Return error if there are unmatched delimiters or unclosed delimiters.
-        // We emit delimiter mismatch errors first, then emit the unclosing delimiter mismatch
-        // because the delimiter mismatch is more likely to be the root cause of error
-        let mut buffer: Vec<_> = unmatched_delims
-            .into_iter()
-            .filter_map(|unmatched_delim| make_unclosed_delims_error(unmatched_delim, psess))
-            .collect();
-        if let Err(errs) = res {
-            // Add unclosing delimiter or diff marker errors
-            buffer.extend(errs);
+    let res = lexer.lex_token_trees(/* is_delimited */ false);
+
+    let mut unmatched_delims: Vec<_> = lexer
+        .diag_info
+        .unmatched_delims
+        .into_iter()
+        .filter_map(|unmatched_delim| make_unclosed_delims_error(unmatched_delim, psess))
+        .collect();
+
+    match res {
+        Ok((_open_spacing, stream)) => {
+            if unmatched_delims.is_empty() {
+                Ok(stream)
+            } else {
+                // Return error if there are unmatched delimiters or unclosed delimiters.
+                Err(unmatched_delims)
+            }
+        }
+        Err(errs) => {
+            // We emit delimiter mismatch errors first, then emit the unclosing delimiter mismatch
+            // because the delimiter mismatch is more likely to be the root cause of error
+            unmatched_delims.extend(errs);
+            Err(unmatched_delims)
         }
-        Err(buffer)
     }
 }
 

compiler/rustc_parse/src/lexer/tokentrees.rs

@@ -1,20 +1,18 @@
 use rustc_ast::token::{self, Delimiter, Token};
 use rustc_ast::tokenstream::{DelimSpacing, DelimSpan, Spacing, TokenStream, TokenTree};
 use rustc_ast_pretty::pprust::token_to_string;
-use rustc_errors::{Applicability, Diag};
-use rustc_span::symbol::kw;
+use rustc_errors::Diag;
 
 use super::diagnostics::{report_suspicious_mismatch_block, same_indentation_level};
 use super::{Lexer, UnmatchedDelim};
-use crate::Parser;
 
 impl<'psess, 'src> Lexer<'psess, 'src> {
     // Lex into a token stream. The `Spacing` in the result is that of the
     // opening delimiter.
     pub(super) fn lex_token_trees(
         &mut self,
         is_delimited: bool,
-    ) -> (Spacing, TokenStream, Result<(), Vec<Diag<'psess>>>) {
+    ) -> Result<(Spacing, TokenStream), Vec<Diag<'psess>>> {
         // Move past the opening delimiter.
         let open_spacing = self.bump_minimal();
 
@@ -27,25 +25,25 @@ impl<'psess, 'src> Lexer<'psess, 'src> {
                     debug_assert!(!matches!(delim, Delimiter::Invisible(_)));
                     buf.push(match self.lex_token_tree_open_delim(delim) {
                         Ok(val) => val,
-                        Err(errs) => return (open_spacing, TokenStream::new(buf), Err(errs)),
+                        Err(errs) => return Err(errs),
                     })
                 }
                 token::CloseDelim(delim) => {
                     // Invisible delimiters cannot occur here because `TokenTreesReader` parses
                     // code directly from strings, with no macro expansion involved.
                     debug_assert!(!matches!(delim, Delimiter::Invisible(_)));
-                    return (
-                        open_spacing,
-                        TokenStream::new(buf),
-                        if is_delimited { Ok(()) } else { Err(vec![self.close_delim_err(delim)]) },
-                    );
+                    return if is_delimited {
+                        Ok((open_spacing, TokenStream::new(buf)))
+                    } else {
+                        Err(vec![self.close_delim_err(delim)])
+                    };
                 }
                 token::Eof => {
-                    return (
-                        open_spacing,
-                        TokenStream::new(buf),
-                        if is_delimited { Err(vec![self.eof_err()]) } else { Ok(()) },
-                    );
+                    return if is_delimited {
+                        Err(vec![self.eof_err()])
+                    } else {
+                        Ok((open_spacing, TokenStream::new(buf)))
+                    };
                 }
                 _ => {
                     // Get the next normal token.
@@ -107,10 +105,7 @@ impl<'psess, 'src> Lexer<'psess, 'src> {
         // Lex the token trees within the delimiters.
         // We stop at any delimiter so we can try to recover if the user
         // uses an incorrect delimiter.
-        let (open_spacing, tts, res) = self.lex_token_trees(/* is_delimited */ true);
-        if let Err(errs) = res {
-            return Err(self.unclosed_delim_err(tts, errs));
-        }
+        let (open_spacing, tts) = self.lex_token_trees(/* is_delimited */ true)?;
 
         // Expand to cover the entire delimited token tree.
         let delim_span = DelimSpan::from_pair(pre_span, self.token.span);
@@ -247,67 +242,6 @@ impl<'psess, 'src> Lexer<'psess, 'src> {
         this_spacing
     }
 
-    fn unclosed_delim_err(
-        &mut self,
-        tts: TokenStream,
-        mut errs: Vec<Diag<'psess>>,
-    ) -> Vec<Diag<'psess>> {
-        // If there are unclosed delims, see if there are diff markers and if so, point them
-        // out instead of complaining about the unclosed delims.
-        let mut parser = Parser::new(self.psess, tts, None);
-        let mut diff_errs = vec![];
-        // Suggest removing a `{` we think appears in an `if`/`while` condition.
-        // We want to suggest removing a `{` only if we think we're in an `if`/`while` condition,
-        // but we have no way of tracking this in the lexer itself, so we piggyback on the parser.
-        let mut in_cond = false;
-        while parser.token != token::Eof {
-            if let Err(diff_err) = parser.err_vcs_conflict_marker() {
-                diff_errs.push(diff_err);
-            } else if parser.is_keyword_ahead(0, &[kw::If, kw::While]) {
-                in_cond = true;
-            } else if matches!(
-                parser.token.kind,
-                token::CloseDelim(Delimiter::Brace) | token::FatArrow
-            ) {
-                // End of the `if`/`while` body, or the end of a `match` guard.
-                in_cond = false;
-            } else if in_cond && parser.token == token::OpenDelim(Delimiter::Brace) {
-                // Store the `&&` and `let` to use their spans later when creating the diagnostic
-                let maybe_andand = parser.look_ahead(1, |t| t.clone());
-                let maybe_let = parser.look_ahead(2, |t| t.clone());
-                if maybe_andand == token::OpenDelim(Delimiter::Brace) {
-                    // This might be the beginning of the `if`/`while` body (i.e., the end of the
-                    // condition).
-                    in_cond = false;
-                } else if maybe_andand == token::AndAnd && maybe_let.is_keyword(kw::Let) {
-                    let mut err = parser.dcx().struct_span_err(
-                        parser.token.span,
-                        "found a `{` in the middle of a let-chain",
-                    );
-                    err.span_suggestion(
-                        parser.token.span,
-                        "consider removing this brace to parse the `let` as part of the same chain",
-                        "",
-                        Applicability::MachineApplicable,
-                    );
-                    err.span_label(
-                        maybe_andand.span.to(maybe_let.span),
-                        "you might have meant to continue the let-chain here",
-                    );
-                    errs.push(err);
-                }
-            }
-            parser.bump();
-        }
-        if !diff_errs.is_empty() {
-            for err in errs {
-                err.cancel();
-            }
-            return diff_errs;
-        }
-        errs
-    }
-
     fn close_delim_err(&mut self, delim: Delimiter) -> Diag<'psess> {
         // An unexpected closing delimiter (i.e., there is no matching opening delimiter).
         let token_str = token_to_string(&self.token);

compiler/rustc_symbol_mangling/src/legacy.rs

@@ -2,7 +2,7 @@ use std::fmt::{self, Write};
 use std::mem::{self, discriminant};
 
 use rustc_data_structures::stable_hasher::{Hash64, HashStable, StableHasher};
-use rustc_hir::def_id::CrateNum;
+use rustc_hir::def_id::{CrateNum, DefId};
 use rustc_hir::definitions::{DefPathData, DisambiguatedDefPathData};
 use rustc_middle::bug;
 use rustc_middle::ty::print::{PrettyPrinter, Print, PrintError, Printer};
@@ -378,6 +378,33 @@ impl<'tcx> Printer<'tcx> for SymbolPrinter<'tcx> {
             Ok(())
         }
     }
+
+    fn print_impl_path(
+        &mut self,
+        impl_def_id: DefId,
+        args: &'tcx [GenericArg<'tcx>],
+        mut self_ty: Ty<'tcx>,
+        mut impl_trait_ref: Option<ty::TraitRef<'tcx>>,
+    ) -> Result<(), PrintError> {
+        let mut typing_env = ty::TypingEnv::post_analysis(self.tcx, impl_def_id);
+        if !args.is_empty() {
+            typing_env.param_env =
+                ty::EarlyBinder::bind(typing_env.param_env).instantiate(self.tcx, args);
+        }
+
+        match &mut impl_trait_ref {
+            Some(impl_trait_ref) => {
+                assert_eq!(impl_trait_ref.self_ty(), self_ty);
+                *impl_trait_ref = self.tcx.normalize_erasing_regions(typing_env, *impl_trait_ref);
+                self_ty = impl_trait_ref.self_ty();
+            }
+            None => {
+                self_ty = self.tcx.normalize_erasing_regions(typing_env, self_ty);
+            }
+        }
+
+        self.default_print_impl_path(impl_def_id, args, self_ty, impl_trait_ref)
+    }
 }
 
 impl<'tcx> PrettyPrinter<'tcx> for SymbolPrinter<'tcx> {

compiler/rustc_target/src/callconv/powerpc64.rs

@@ -99,7 +99,7 @@ where
     Ty: TyAbiInterface<'a, C> + Copy,
     C: HasDataLayout + HasTargetSpec,
 {
-    let abi = if cx.target_spec().env == "musl" {
+    let abi = if cx.target_spec().env == "musl" || cx.target_spec().os == "freebsd" {
         ELFv2
     } else if cx.target_spec().os == "aix" {
         AIX

compiler/rustc_target/src/spec/targets/powerpc64_unknown_freebsd.rs

@@ -11,7 +11,7 @@ pub(crate) fn target() -> Target {
     Target {
         llvm_target: "powerpc64-unknown-freebsd".into(),
         metadata: crate::spec::TargetMetadata {
-            description: Some("PPC64 FreeBSD (ELFv1 and ELFv2)".into()),
+            description: Some("PPC64 FreeBSD (ELFv2)".into()),
             tier: Some(3),
             host_tools: Some(true),
             std: Some(true),

library/core/src/hint.rs

@@ -310,13 +310,17 @@ pub fn spin_loop() {
 /// behavior in the calling code. This property makes `black_box` useful for writing code in which
 /// certain optimizations are not desired, such as benchmarks.
 ///
+/// <div class="warning">
+///
 /// Note however, that `black_box` is only (and can only be) provided on a "best-effort" basis. The
 /// extent to which it can block optimisations may vary depending upon the platform and code-gen
 /// backend used. Programs cannot rely on `black_box` for *correctness*, beyond it behaving as the
 /// identity function. As such, it **must not be relied upon to control critical program behavior.**
 /// This also means that this function does not offer any guarantees for cryptographic or security
 /// purposes.
 ///
+/// </div>
+///
 /// [`std::convert::identity`]: crate::convert::identity
 ///
 /// # When is this useful?
@@ -357,7 +361,7 @@ pub fn spin_loop() {
 /// ```
 /// use std::hint::black_box;
 ///
-/// // Same `contains` function
+/// // Same `contains` function.
 /// fn contains(haystack: &[&str], needle: &str) -> bool {
 ///     haystack.iter().any(|x| x == &needle)
 /// }
@@ -366,8 +370,13 @@ pub fn spin_loop() {
 ///     let haystack = vec!["abc", "def", "ghi", "jkl", "mno"];
 ///     let needle = "ghi";
 ///     for _ in 0..10 {
-///         // Adjust our benchmark loop contents
-///         black_box(contains(black_box(&haystack), black_box(needle)));
+///         // Force the compiler to run `contains`, even though it is a pure function whose
+///         // results are unused.
+///         black_box(contains(
+///             // Prevent the compiler from making assumptions about the input.
+///             black_box(&haystack),
+///             black_box(needle),
+///         ));
 ///     }
 /// }
 /// ```
@@ -382,6 +391,83 @@ pub fn spin_loop() {
 ///
 /// This makes our benchmark much more realistic to how the function would actually be used, where
 /// arguments are usually not known at compile time and the result is used in some way.
+///
+/// # How to use this
+///
+/// In practice, `black_box` serves two purposes:
+///
+/// 1. It prevents the compiler from making optimizations related to the value returned by `black_box`
+/// 2. It forces the value passed to `black_box` to be calculated, even if the return value of `black_box` is unused
+///
+/// ```
+/// use std::hint::black_box;
+///
+/// let zero = 0;
+/// let five = 5;
+///
+/// // The compiler will see this and remove the `* five` call, because it knows that multiplying
+/// // any integer by 0 will result in 0.
+/// let c = zero * five;
+///
+/// // Adding `black_box` here disables the compiler's ability to reason about the first operand in the multiplication.
+/// // It is forced to assume that it can be any possible number, so it cannot remove the `* five`
+/// // operation.
+/// let c = black_box(zero) * five;
+/// ```
+///
+/// While most cases will not be as clear-cut as the above example, it still illustrates how
+/// `black_box` can be used. When benchmarking a function, you usually want to wrap its inputs in
+/// `black_box` so the compiler cannot make optimizations that would be unrealistic in real-life
+/// use.
+///
+/// ```
+/// use std::hint::black_box;
+///
+/// // This is a simple function that increments its input by 1. Note that it is pure, meaning it
+/// // has no side-effects. This function has no effect if its result is unused. (An example of a
+/// // function *with* side-effects is `println!()`.)
+/// fn increment(x: u8) -> u8 {
+///     x + 1
+/// }
+///
+/// // Here, we call `increment` but discard its result. The compiler, seeing this and knowing that
+/// // `increment` is pure, will eliminate this function call entirely. This may not be desired,
+/// // though, especially if we're trying to track how much time `increment` takes to execute.
+/// let _ = increment(black_box(5));
+///
+/// // Here, we force `increment` to be executed. This is because the compiler treats `black_box`
+/// // as if it has side-effects, and thus must compute its input.
+/// let _ = black_box(increment(black_box(5)));
+/// ```
+///
+/// There may be additional situations where you want to wrap the result of a function in
+/// `black_box` to force its execution. This is situational though, and may not have any effect
+/// (such as when the function returns a zero-sized type such as [`()` unit][unit]).
+///
+/// Note that `black_box` has no effect on how its input is treated, only its output. As such,
+/// expressions passed to `black_box` may still be optimized:
+///
+/// ```
+/// use std::hint::black_box;
+///
+/// // The compiler sees this...
+/// let y = black_box(5 * 10);
+///
+/// // ...as this. As such, it will likely simplify `5 * 10` to just `50`.
+/// let _0 = 5 * 10;
+/// let y = black_box(_0);
+/// ```
+///
+/// In the above example, the `5 * 10` expression is considered distinct from the `black_box` call,
+/// and thus is still optimized by the compiler. You can prevent this by moving the multiplication
+/// operation outside of `black_box`:
+///
+/// ```
+/// use std::hint::black_box;
+///
+/// // No assumptions can be made about either operand, so the multiplication is not optimized out.
+/// let y = black_box(5) * black_box(10);
+/// ```
 #[inline]
 #[stable(feature = "bench_black_box", since = "1.66.0")]
 #[rustc_const_unstable(feature = "const_black_box", issue = "none")]

src/bootstrap/src/utils/cc_detect.rs

@@ -44,6 +44,16 @@ fn cc2ar(cc: &Path, target: TargetSelection) -> Option<PathBuf> {
         Some(PathBuf::from("ar"))
     } else if target.contains("vxworks") {
         Some(PathBuf::from("wr-ar"))
+    } else if target.contains("-nto-") {
+        if target.starts_with("i586") {
+            Some(PathBuf::from("ntox86-ar"))
+        } else if target.starts_with("aarch64") {
+            Some(PathBuf::from("ntoaarch64-ar"))
+        } else if target.starts_with("x86_64") {
+            Some(PathBuf::from("ntox86_64-ar"))
+        } else {
+            panic!("Unknown architecture, cannot determine archiver for Neutrino QNX");
+        }
     } else if target.contains("android") || target.contains("-wasi") {
         Some(cc.parent().unwrap().join(PathBuf::from("llvm-ar")))
     } else {

src/doc/rustc/src/platform-support.md

@@ -343,7 +343,7 @@ target | std | host | notes
 [`powerpc-unknown-openbsd`](platform-support/powerpc-unknown-openbsd.md) | * |  |
 [`powerpc-wrs-vxworks-spe`](platform-support/vxworks.md) | ✓ |  |
 [`powerpc-wrs-vxworks`](platform-support/vxworks.md) | ✓ |  |
-`powerpc64-unknown-freebsd` | ✓ | ✓ | PPC64 FreeBSD (ELFv1 and ELFv2)
+`powerpc64-unknown-freebsd` | ✓ | ✓ | PPC64 FreeBSD (ELFv2)
 `powerpc64le-unknown-freebsd` | ✓ | ✓ | PPC64LE FreeBSD
 `powerpc-unknown-freebsd` | ? |   | PowerPC FreeBSD
 `powerpc64-unknown-linux-musl` | ? |  | 64-bit PowerPC Linux with musl 1.2.3

src/tools/run-make-support/src/external_deps/rustc.rs

@@ -325,6 +325,12 @@ impl Rustc {
         self
     }
 
+    /// Pass the `--verbose` flag.
+    pub fn verbose(&mut self) -> &mut Self {
+        self.cmd.arg("--verbose");
+        self
+    }
+
     /// `EXTRARSCXXFLAGS`
     pub fn extra_rs_cxx_flags(&mut self) -> &mut Self {
         // Adapted from tools.mk (trimmed):

tests/run-make/link-args-order/rmake.rs

@@ -15,15 +15,17 @@ fn main() {
         .link_args("b c")
         .link_args("d e")
         .link_arg("f")
+        .arg("--print=link-args")
         .run_fail()
-        .assert_stderr_contains(r#""a" "b" "c" "d" "e" "f""#);
+        .assert_stdout_contains(r#""a" "b" "c" "d" "e" "f""#);
     rustc()
         .input("empty.rs")
         .linker_flavor(linker)
         .arg("-Zpre-link-arg=a")
         .arg("-Zpre-link-args=b c")
         .arg("-Zpre-link-args=d e")
         .arg("-Zpre-link-arg=f")
+        .arg("--print=link-args")
         .run_fail()
-        .assert_stderr_contains(r#""a" "b" "c" "d" "e" "f""#);
+        .assert_stdout_contains(r#""a" "b" "c" "d" "e" "f""#);
 }

tests/run-make/link-dedup/rmake.rs

@@ -14,13 +14,13 @@ fn main() {
     rustc().input("depb.rs").run();
     rustc().input("depc.rs").run();
 
-    let output = rustc().input("empty.rs").cfg("bar").run_fail();
-    output.assert_stderr_contains(needle_from_libs(&["testa", "testb", "testa"]));
+    let output = rustc().input("empty.rs").cfg("bar").arg("--print=link-args").run_fail();
+    output.assert_stdout_contains(needle_from_libs(&["testa", "testb", "testa"]));
 
-    let output = rustc().input("empty.rs").run_fail();
-    output.assert_stderr_contains(needle_from_libs(&["testa"]));
-    output.assert_stderr_not_contains(needle_from_libs(&["testb"]));
-    output.assert_stderr_not_contains(needle_from_libs(&["testa", "testa", "testa"]));
+    let output = rustc().input("empty.rs").arg("--print=link-args").run_fail();
+    output.assert_stdout_contains(needle_from_libs(&["testa"]));
+    output.assert_stdout_not_contains(needle_from_libs(&["testb"]));
+    output.assert_stdout_not_contains(needle_from_libs(&["testa", "testa", "testa"]));
     // Adjacent identical native libraries are no longer deduplicated if
     // they come from different crates (https://github.com/rust-lang/rust/pull/103311)
     // so the following will fail:

tests/run-make/linker-warning/fake-linker.rs

@@ -0,0 +1,13 @@
+fn main() {
+    for arg in std::env::args() {
+        match &*arg {
+            "run_make_info" => println!("foo"),
+            "run_make_warn" => eprintln!("warning: bar"),
+            "run_make_error" => {
+                eprintln!("error: baz");
+                std::process::exit(1);
+            }
+            _ => (),
+        }
+    }
+}

tests/run-make/linker-warning/main.rs

@@ -0,0 +1 @@
+fn main() {}

tests/run-make/linker-warning/rmake.rs

@@ -0,0 +1,28 @@
+use run_make_support::{Rustc, rustc};
+
+fn run_rustc() -> Rustc {
+    let mut rustc = rustc();
+    rustc.arg("main.rs").output("main").linker("./fake-linker");
+    rustc
+}
+
+fn main() {
+    // first, compile our linker
+    rustc().arg("fake-linker.rs").output("fake-linker").run();
+
+    // Make sure we don't show the linker args unless `--verbose` is passed
+    run_rustc()
+        .link_arg("run_make_error")
+        .verbose()
+        .run_fail()
+        .assert_stderr_contains_regex("fake-linker.*run_make_error")
+        .assert_stderr_not_contains("object files omitted")
+        .assert_stderr_contains_regex(r"lib[/\\]libstd");
+    run_rustc()
+        .link_arg("run_make_error")
+        .run_fail()
+        .assert_stderr_contains("fake-linker")
+        .assert_stderr_contains("object files omitted")
+        .assert_stderr_contains_regex(r"\{")
+        .assert_stderr_not_contains_regex(r"lib[/\\]libstd");
+}

tests/ui/parser/brace-in-let-chain.rs

@@ -3,15 +3,15 @@
 #![feature(let_chains)]
 fn main() {
     if let () = ()
-        && let () = () { //~ERROR: found a `{` in the middle of a let-chain
+        && let () = () {
         && let () = ()
     {
     }
 }
 
 fn quux() {
     while let () = ()
-        && let () = () { //~ERROR: found a `{` in the middle of a let-chain
+        && let () = () {
         && let () = ()
     {
     }

tests/ui/parser/brace-in-let-chain.stderr

@@ -27,33 +27,5 @@ LL |     }
 LL | }
    |                                                     ^
 
-error: found a `{` in the middle of a let-chain
-  --> $DIR/brace-in-let-chain.rs:14:24
-   |
-LL |         && let () = () {
-   |                        ^
-LL |         && let () = ()
-   |         ------ you might have meant to continue the let-chain here
-   |
-help: consider removing this brace to parse the `let` as part of the same chain
-   |
-LL -         && let () = () {
-LL +         && let () = ()
-   |
-
-error: found a `{` in the middle of a let-chain
-  --> $DIR/brace-in-let-chain.rs:6:24
-   |
-LL |         && let () = () {
-   |                        ^
-LL |         && let () = ()
-   |         ------ you might have meant to continue the let-chain here
-   |
-help: consider removing this brace to parse the `let` as part of the same chain
-   |
-LL -         && let () = () {
-LL +         && let () = ()
-   |
-
-error: aborting due to 3 previous errors
+error: aborting due to 1 previous error
 

tests/ui/parser/diff-markers/unclosed-delims-in-macro.rs

@@ -1,9 +1,11 @@
+// The diff marker detection was removed for this example, because it relied on
+// the lexer having a dependency on the parser, which was horrible.
+
 macro_rules! foo {
 <<<<<<< HEAD
-    //~^ ERROR encountered diff marker
     () {
 =======
     () { //
 >>>>>>> 7a4f13c blah blah blah
     }
-}
+} //~ this file contains an unclosed delimiter

tests/ui/parser/diff-markers/unclosed-delims-in-macro.stderr

@@ -1,23 +1,16 @@
-error: encountered diff marker
-  --> $DIR/unclosed-delims-in-macro.rs:2:1
+error: this file contains an unclosed delimiter
+  --> $DIR/unclosed-delims-in-macro.rs:11:48
    |
+LL | macro_rules! foo {
+   |                  - unclosed delimiter
 LL | <<<<<<< HEAD
-   | ^^^^^^^ between this marker and `=======` is the code that we're merging into
+LL |     () {
+   |        - this delimiter might not be properly closed...
 ...
-LL | =======
-   | ------- between this marker and `>>>>>>>` is the incoming code
-LL |     () { //
-LL | >>>>>>> 7a4f13c blah blah blah
-   | ^^^^^^^ this marker concludes the conflict region
-   |
-   = note: conflict markers indicate that a merge was started but could not be completed due to merge conflicts
-           to resolve a conflict, keep only the code you want and then delete the lines containing conflict markers
-   = help: if you're having merge conflicts after pulling new code:
-           the top section is the code you already had and the bottom section is the remote code
-           if you're in the middle of a rebase:
-           the top section is the code being rebased onto and the bottom section is the code coming from the current commit being rebased
-   = note: for an explanation on these markers from the `git` documentation:
-           visit <https://git-scm.com/book/en/v2/Git-Tools-Advanced-Merging#_checking_out_conflicts>
+LL | }
+   | -                                             ^
+   | |
+   | ...as it matches this but it has different indentation
 
 error: aborting due to 1 previous error
 

tests/ui/parser/diff-markers/unclosed-delims.rs

@@ -1,18 +1,12 @@
+// The diff marker detection was removed for this example, because it relied on
+// the lexer having a dependency on the parser, which was horrible.
+
 mod tests {
     #[test]
 <<<<<<< HEAD
-//~^ ERROR encountered diff marker
-//~| NOTE between this marker and `=======`
-
-//~| NOTE conflict markers indicate that
-//~| HELP if you're having merge conflicts
-//~| NOTE for an explanation on these markers
-
     fn test1() {
 =======
-//~^ NOTE between this marker and `>>>>>>>`
     fn test2() {
 >>>>>>> 7a4f13c blah blah blah
-//~^ NOTE this marker concludes the conflict region
     }
-}
+} //~ this file contains an unclosed delimiter

tests/ui/parser/diff-markers/unclosed-delims.stderr

@@ -1,23 +1,16 @@
-error: encountered diff marker
-  --> $DIR/unclosed-delims.rs:3:1
+error: this file contains an unclosed delimiter
+  --> $DIR/unclosed-delims.rs:12:48
    |
-LL | <<<<<<< HEAD
-   | ^^^^^^^ between this marker and `=======` is the code that we're merging into
+LL | mod tests {
+   |           - unclosed delimiter
 ...
-LL | =======
-   | ------- between this marker and `>>>>>>>` is the incoming code
+LL |     fn test1() {
+   |                - this delimiter might not be properly closed...
 ...
-LL | >>>>>>> 7a4f13c blah blah blah
-   | ^^^^^^^ this marker concludes the conflict region
-   |
-   = note: conflict markers indicate that a merge was started but could not be completed due to merge conflicts
-           to resolve a conflict, keep only the code you want and then delete the lines containing conflict markers
-   = help: if you're having merge conflicts after pulling new code:
-           the top section is the code you already had and the bottom section is the remote code
-           if you're in the middle of a rebase:
-           the top section is the code being rebased onto and the bottom section is the code coming from the current commit being rebased
-   = note: for an explanation on these markers from the `git` documentation:
-           visit <https://git-scm.com/book/en/v2/Git-Tools-Advanced-Merging#_checking_out_conflicts>
+LL | }
+   | -                                             ^
+   | |
+   | ...as it matches this but it has different indentation
 
 error: aborting due to 1 previous error
 

tests/ui/symbol-names/types.legacy.stderr

@@ -502,5 +502,23 @@ error: demangling-alt(a::b::Type<[T; N]>)
 LL |     #[rustc_symbol_name]
    |     ^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to 84 previous errors
+error: symbol-name(_ZN1a1b35Type$LT$$u5b$u8$u3b$$u20$0$u5d$$GT$17h[HASH]E)
+  --> $DIR/types.rs:272:5
+   |
+LL |     #[rustc_symbol_name]
+   |     ^^^^^^^^^^^^^^^^^^^^
+
+error: demangling(a::b::Type<[u8; 0]>::h[HASH])
+  --> $DIR/types.rs:272:5
+   |
+LL |     #[rustc_symbol_name]
+   |     ^^^^^^^^^^^^^^^^^^^^
+
+error: demangling-alt(a::b::Type<[u8; 0]>)
+  --> $DIR/types.rs:272:5
+   |
+LL |     #[rustc_symbol_name]
+   |     ^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 87 previous errors
 

tests/ui/symbol-names/types.rs

@@ -266,6 +266,17 @@ pub fn b() {
     //[v0]~| ERROR ::b::Type<[_; _]>>)
     //[v0]~| ERROR demangling-alt(<a::b::Type<[_; _]>>)
     impl<const N: usize, T> Type<[T; N]> {}
+
+    const ZERO: usize = 0;
+
+    #[rustc_symbol_name]
+    //[legacy,verbose-legacy]~^ ERROR symbol-name(_ZN1a1b35Type$LT$$u5b$u8$u3b$$u20$0$u5d$$GT$
+    //[legacy,verbose-legacy]~| ERROR demangling(a::b::Type<[u8; 0]>::
+    //[legacy,verbose-legacy]~| ERROR demangling-alt(a::b::Type<[u8; 0]>)
+    //[v0]~^^^^ ERROR symbol-name(_RMsq_NvCsCRATE_HASH_1a1bINtB<REF>_4TypeAhj0_E)
+    //[v0]~| ERROR ::b::Type<[u8; 0usize]>>)
+    //[v0]~| ERROR demangling-alt(<a::b::Type<[u8; 0]>>)
+    impl Type<[u8; ZERO]> {}
 }
 
 fn main() {}

tests/ui/symbol-names/types.v0.stderr

@@ -502,5 +502,23 @@ error: demangling-alt(<a::b::Type<[_; _]>>)
 LL |     #[rustc_symbol_name]
    |     ^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to 84 previous errors
+error: symbol-name(_RMsq_NvCsCRATE_HASH_1a1bINtB<REF>_4TypeAhj0_E)
+  --> $DIR/types.rs:272:5
+   |
+LL |     #[rustc_symbol_name]
+   |     ^^^^^^^^^^^^^^^^^^^^
+
+error: demangling(<a[HASH]::b::Type<[u8; 0usize]>>)
+  --> $DIR/types.rs:272:5
+   |
+LL |     #[rustc_symbol_name]
+   |     ^^^^^^^^^^^^^^^^^^^^
+
+error: demangling-alt(<a::b::Type<[u8; 0]>>)
+  --> $DIR/types.rs:272:5
+   |
+LL |     #[rustc_symbol_name]
+   |     ^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 87 previous errors
 

tests/ui/symbol-names/types.verbose-legacy.stderr

@@ -502,5 +502,23 @@ error: demangling-alt(a::b::Type<[T; N]>)
 LL |     #[rustc_symbol_name]
    |     ^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to 84 previous errors
+error: symbol-name(_ZN1a1b35Type$LT$$u5b$u8$u3b$$u20$0$u5d$$GT$17h[HASH]E)
+  --> $DIR/types.rs:272:5
+   |
+LL |     #[rustc_symbol_name]
+   |     ^^^^^^^^^^^^^^^^^^^^
+
+error: demangling(a::b::Type<[u8; 0]>::h[HASH])
+  --> $DIR/types.rs:272:5
+   |
+LL |     #[rustc_symbol_name]
+   |     ^^^^^^^^^^^^^^^^^^^^
+
+error: demangling-alt(a::b::Type<[u8; 0]>)
+  --> $DIR/types.rs:272:5
+   |
+LL |     #[rustc_symbol_name]
+   |     ^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 87 previous errors