Merge from rustc

Author: BoxyUwU

ci/ci.sh

@@ -14,7 +14,9 @@ function endgroup {
 begingroup "Building Miri"
 
 # Global configuration
-export RUSTFLAGS="-D warnings"
+# We are getting some odd linker warnings on macOS, make sure they do not fail the build.
+# (See <https://github.com/rust-lang/rust/issues/136086>.)
+export RUSTFLAGS="-D warnings -A linker-messages"
 export CARGO_INCREMENTAL=0
 export CARGO_EXTRA_FLAGS="--locked"
 

rust-version

@@ -1 +1 @@
-01706e1a34c87656fcbfce198608f4cd2ac6461a
+2f0ad2a71e4a4528bb80bcb24bf8fa4e50cb87c2

src/bin/miri.rs

@@ -29,11 +29,12 @@ use std::num::NonZero;
 use std::ops::Range;
 use std::path::PathBuf;
 use std::str::FromStr;
-use std::sync::atomic::{AtomicI32, Ordering};
-use std::sync::{Arc, Once};
+use std::sync::Once;
+use std::sync::atomic::{AtomicI32, AtomicU32, Ordering};
 
 use miri::{
-    BacktraceStyle, BorrowTrackerMethod, MiriConfig, ProvenanceMode, RetagFields, ValidationMode,
+    BacktraceStyle, BorrowTrackerMethod, MiriConfig, MiriEntryFnType, ProvenanceMode, RetagFields,
+    ValidationMode,
 };
 use rustc_abi::ExternAbi;
 use rustc_data_structures::sync;
@@ -51,7 +52,7 @@ use rustc_middle::query::LocalCrate;
 use rustc_middle::traits::{ObligationCause, ObligationCauseCode};
 use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_middle::util::Providers;
-use rustc_session::config::{CrateType, EntryFnType, ErrorOutputType, OptLevel};
+use rustc_session::config::{CrateType, ErrorOutputType, OptLevel};
 use rustc_session::search_paths::PathKind;
 use rustc_session::{CtfeBacktrace, EarlyDiagCtxt};
 use rustc_span::def_id::DefId;
@@ -73,9 +74,9 @@ impl MiriCompilerCalls {
     }
 }
 
-fn entry_fn(tcx: TyCtxt<'_>) -> (DefId, EntryFnType) {
-    if let Some(entry_def) = tcx.entry_fn(()) {
-        return entry_def;
+fn entry_fn(tcx: TyCtxt<'_>) -> (DefId, MiriEntryFnType) {
+    if let Some((def_id, entry_type)) = tcx.entry_fn(()) {
+        return (def_id, MiriEntryFnType::Rustc(entry_type));
     }
     // Look for a symbol in the local crate named `miri_start`, and treat that as the entry point.
     let sym = tcx.exported_symbols(LOCAL_CRATE).iter().find_map(|(sym, _)| {
@@ -102,7 +103,7 @@ fn entry_fn(tcx: TyCtxt<'_>) -> (DefId, EntryFnType) {
         .is_ok();
 
         if correct_func_sig {
-            (*id, EntryFnType::Start)
+            (*id, MiriEntryFnType::MiriStart)
         } else {
             tcx.dcx().fatal(
                 "`miri_start` must have the following signature:\n\
@@ -182,7 +183,8 @@ impl rustc_driver::Callbacks for MiriCompilerCalls {
         if let Some(many_seeds) = self.many_seeds.take() {
             assert!(config.seed.is_none());
             let exit_code = sync::IntoDynSyncSend(AtomicI32::new(rustc_driver::EXIT_SUCCESS));
-            sync::par_for_each_in(many_seeds.seeds, |seed| {
+            let num_failed = sync::IntoDynSyncSend(AtomicU32::new(0));
+            sync::par_for_each_in(many_seeds.seeds.clone(), |seed| {
                 let mut config = config.clone();
                 config.seed = Some(seed.into());
                 eprintln!("Trying seed: {seed}");
@@ -196,8 +198,13 @@ impl rustc_driver::Callbacks for MiriCompilerCalls {
                         std::process::exit(return_code);
                     }
                     exit_code.store(return_code, Ordering::Relaxed);
+                    num_failed.fetch_add(1, Ordering::Relaxed);
                 }
             });
+            let num_failed = num_failed.0.into_inner();
+            if num_failed > 0 {
+                eprintln!("{num_failed}/{total} SEEDS FAILED", total = many_seeds.seeds.count());
+            }
             std::process::exit(exit_code.0.into_inner());
         } else {
             let return_code = miri::eval_entry(tcx, entry_def_id, entry_type, config)
@@ -370,13 +377,10 @@ fn init_late_loggers(early_dcx: &EarlyDiagCtxt, tcx: TyCtxt<'_>) {
 fn run_compiler_and_exit(
     args: &[String],
     callbacks: &mut (dyn rustc_driver::Callbacks + Send),
-    using_internal_features: Arc<std::sync::atomic::AtomicBool>,
 ) -> ! {
     // Invoke compiler, and handle return code.
     let exit_code = rustc_driver::catch_with_exit_code(move || {
-        rustc_driver::RunCompiler::new(args, callbacks)
-            .set_using_internal_features(using_internal_features)
-            .run();
+        rustc_driver::run_compiler(args, callbacks);
         Ok(())
     });
     std::process::exit(exit_code)
@@ -467,8 +471,7 @@ fn main() {
     // If the environment asks us to actually be rustc, then do that.
     if let Some(crate_kind) = env::var_os("MIRI_BE_RUSTC") {
         // Earliest rustc setup.
-        let using_internal_features =
-            rustc_driver::install_ice_hook(rustc_driver::DEFAULT_BUG_REPORT_URL, |_| ());
+        rustc_driver::install_ice_hook(rustc_driver::DEFAULT_BUG_REPORT_URL, |_| ());
         rustc_driver::init_rustc_env_logger(&early_dcx);
 
         let target_crate = if crate_kind == "target" {
@@ -492,16 +495,11 @@ fn main() {
         }
 
         // We cannot use `rustc_driver::main` as we want it to use `args` as the CLI arguments.
-        run_compiler_and_exit(
-            &args,
-            &mut MiriBeRustCompilerCalls { target_crate },
-            using_internal_features,
-        )
+        run_compiler_and_exit(&args, &mut MiriBeRustCompilerCalls { target_crate })
     }
 
     // Add an ICE bug report hook.
-    let using_internal_features =
-        rustc_driver::install_ice_hook("https://github.com/rust-lang/miri/issues/new", |_| ());
+    rustc_driver::install_ice_hook("https://github.com/rust-lang/miri/issues/new", |_| ());
 
     // Init loggers the Miri way.
     init_early_loggers(&early_dcx);
@@ -725,19 +723,14 @@ fn main() {
 
     // Ensure we have parallelism for many-seeds mode.
     if many_seeds.is_some() && !rustc_args.iter().any(|arg| arg.starts_with("-Zthreads=")) {
-        rustc_args.push(format!(
-            "-Zthreads={}",
-            std::thread::available_parallelism().map_or(1, |n| n.get())
-        ));
+        // Clamp to 8 threads; things get a lot less efficient beyond that due to lock contention.
+        let threads = std::thread::available_parallelism().map_or(1, |n| n.get()).min(8);
+        rustc_args.push(format!("-Zthreads={threads}"));
     }
     let many_seeds =
         many_seeds.map(|seeds| ManySeedsConfig { seeds, keep_going: many_seeds_keep_going });
 
     debug!("rustc arguments: {:?}", rustc_args);
     debug!("crate arguments: {:?}", miri_config.args);
-    run_compiler_and_exit(
-        &rustc_args,
-        &mut MiriCompilerCalls::new(miri_config, many_seeds),
-        using_internal_features,
-    )
+    run_compiler_and_exit(&rustc_args, &mut MiriCompilerCalls::new(miri_config, many_seeds))
 }

src/eval.rs

@@ -19,6 +19,12 @@ use crate::diagnostics::report_leaks;
 use crate::shims::tls;
 use crate::*;
 
+#[derive(Copy, Clone, Debug)]
+pub enum MiriEntryFnType {
+    MiriStart,
+    Rustc(EntryFnType),
+}
+
 /// When the main thread would exit, we will yield to any other thread that is ready to execute.
 /// But we must only do that a finite number of times, or a background thread running `loop {}`
 /// will hang the program.
@@ -272,7 +278,7 @@ impl<'tcx> MainThreadState<'tcx> {
 pub fn create_ecx<'tcx>(
     tcx: TyCtxt<'tcx>,
     entry_id: DefId,
-    entry_type: EntryFnType,
+    entry_type: MiriEntryFnType,
     config: &MiriConfig,
 ) -> InterpResult<'tcx, InterpCx<'tcx, MiriMachine<'tcx>>> {
     let typing_env = ty::TypingEnv::fully_monomorphized();
@@ -300,7 +306,7 @@ pub fn create_ecx<'tcx>(
     // Setup first stack frame.
     let entry_instance = ty::Instance::mono(tcx, entry_id);
 
-    // First argument is constructed later, because it's skipped if the entry function uses #[start].
+    // First argument is constructed later, because it's skipped for `miri_start.`
 
     // Second argument (argc): length of `config.args`.
     let argc =
@@ -373,11 +379,9 @@ pub fn create_ecx<'tcx>(
     // Call start function.
 
     match entry_type {
-        EntryFnType::Main { .. } => {
+        MiriEntryFnType::Rustc(EntryFnType::Main { .. }) => {
             let start_id = tcx.lang_items().start_fn().unwrap_or_else(|| {
-                tcx.dcx().fatal(
-                    "could not find start function. Make sure the entry point is marked with `#[start]`."
-                );
+                tcx.dcx().fatal("could not find start lang item");
             });
             let main_ret_ty = tcx.fn_sig(entry_id).no_bound_vars().unwrap().output();
             let main_ret_ty = main_ret_ty.no_bound_vars().unwrap();
@@ -413,7 +417,7 @@ pub fn create_ecx<'tcx>(
                 StackPopCleanup::Root { cleanup: true },
             )?;
         }
-        EntryFnType::Start => {
+        MiriEntryFnType::MiriStart => {
             ecx.call_function(
                 entry_instance,
                 ExternAbi::Rust,
@@ -434,7 +438,7 @@ pub fn create_ecx<'tcx>(
 pub fn eval_entry<'tcx>(
     tcx: TyCtxt<'tcx>,
     entry_id: DefId,
-    entry_type: EntryFnType,
+    entry_type: MiriEntryFnType,
     config: MiriConfig,
 ) -> Option<i32> {
     // Copy setting before we move `config`.

src/helpers.rs

@@ -38,9 +38,10 @@ fn try_resolve_did(tcx: TyCtxt<'_>, path: &[&str], namespace: Option<Namespace>)
         item: DefId,
         name: &'a str,
     ) -> impl Iterator<Item = DefId> + 'a {
+        let name = Symbol::intern(name);
         tcx.module_children(item)
             .iter()
-            .filter(move |item| item.ident.name.as_str() == name)
+            .filter(move |item| item.ident.name == name)
             .map(move |item| item.res.def_id())
     }
 

src/lib.rs

@@ -135,8 +135,8 @@ pub use crate::diagnostics::{
     EvalContextExt as _, NonHaltingDiagnostic, TerminationInfo, report_error,
 };
 pub use crate::eval::{
-    AlignmentCheck, BacktraceStyle, IsolatedOp, MiriConfig, RejectOpWith, ValidationMode,
-    create_ecx, eval_entry,
+    AlignmentCheck, BacktraceStyle, IsolatedOp, MiriConfig, MiriEntryFnType, RejectOpWith,
+    ValidationMode, create_ecx, eval_entry,
 };
 pub use crate::helpers::{AccessKind, EvalContextExt as _};
 pub use crate::intrinsics::EvalContextExt as _;

test-cargo-miri/no-std-smoke/src/main.rs

@@ -1,7 +1,7 @@
 // Copied from tests/pass/no-std.rs
 
-#![feature(start)]
 #![no_std]
+#![no_main]
 
 // Plumbing to let us use `writeln!` to host stdout:
 
@@ -22,8 +22,8 @@ impl Write for Host {
     }
 }
 
-#[start]
-fn start(_: isize, _: *const *const u8) -> isize {
+#[no_mangle]
+fn miri_start(_: isize, _: *const *const u8) -> isize {
     writeln!(Host, "hello, world!").unwrap();
     0
 }

tests/fail/alloc/alloc_error_handler_custom.rs

@@ -1,8 +1,9 @@
 //@compile-flags: -Cpanic=abort
-#![feature(start, core_intrinsics)]
+#![feature(core_intrinsics)]
 #![feature(alloc_error_handler)]
 #![feature(allocator_api)]
 #![no_std]
+#![no_main]
 
 extern crate alloc;
 
@@ -43,7 +44,7 @@ mod plumbing {
     static GLOBAL: NoAlloc = NoAlloc;
 }
 
-#[start]
-fn start(_: isize, _: *const *const u8) -> isize {
+#[no_mangle]
+fn miri_start(_argc: isize, _argv: *const *const u8) -> isize {
     handle_alloc_error(Layout::for_value(&0));
 }

tests/fail/alloc/alloc_error_handler_custom.stderr

@@ -16,7 +16,7 @@ LL | fn alloc_error_handler(layout: Layout) -> ! {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = note: inside `alloc::alloc::handle_alloc_error::rt_error` at RUSTLIB/alloc/src/alloc.rs:LL:CC
    = note: inside `alloc::alloc::handle_alloc_error` at RUSTLIB/alloc/src/alloc.rs:LL:CC
-note: inside `start`
+note: inside `miri_start`
   --> tests/fail/alloc/alloc_error_handler_custom.rs:LL:CC
    |
 LL |     handle_alloc_error(Layout::for_value(&0));

tests/fail/alloc/alloc_error_handler_no_std.rs

@@ -1,8 +1,9 @@
 //@compile-flags: -Cpanic=abort
-#![feature(start, core_intrinsics)]
+#![feature(core_intrinsics)]
 #![feature(alloc_error_handler)]
 #![feature(allocator_api)]
 #![no_std]
+#![no_main]
 
 extern crate alloc;
 
@@ -41,7 +42,7 @@ mod plumbing {
     static GLOBAL: NoAlloc = NoAlloc;
 }
 
-#[start]
-fn start(_: isize, _: *const *const u8) -> isize {
+#[no_mangle]
+fn miri_start(_argc: isize, _argv: *const *const u8) -> isize {
     handle_alloc_error(Layout::for_value(&0));
 }