Miri subtree update

src/tools/miri/.github/workflows/ci.yml

@@ -30,6 +30,8 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - uses: ./.github/workflows/setup
+        with:
+          toolchain_flags: "--host ${{ matrix.host_target }}"
 
       # The `style` job only runs on Linux; this makes sure the Windows-host-specific
       # code is also covered by clippy.

src/tools/miri/.github/workflows/setup/action.yml

@@ -1,5 +1,9 @@
 name: "Miri CI setup"
 description: "Sets up Miri CI"
+inputs:
+  toolchain_flags:
+    required: false
+    default: ''
 runs:
   using: "composite"
   steps:
@@ -45,7 +49,7 @@ runs:
             echo "Building against latest rustc git version"
             git ls-remote https://github.com/rust-lang/rust/ HEAD | cut -f 1 > rust-version
           fi
-          ./miri toolchain
+          ./miri toolchain ${{ inputs.toolchain_flags }}
         shell: bash
 
       - name: Show Rust version (miri toolchain)

src/tools/miri/Cargo.toml

@@ -67,6 +67,10 @@ default = ["stack-cache"]
 stack-cache = []
 stack-cache-consistency-check = ["stack-cache"]
 
+[lints.rust.unexpected_cfgs]
+level = "warn"
+check-cfg = ['cfg(bootstrap)']
+
 # Be aware that this file is inside a workspace when used via the
 # submodule in the rustc repo. That means there are many cargo features
 # we cannot use, such as profiles.

src/tools/miri/ci/ci.sh

@@ -1,5 +1,5 @@
 #!/bin/bash
-set -euo pipefail
+set -eu
 
 function begingroup {
   echo "::group::$@"
@@ -11,6 +11,17 @@ function endgroup {
   echo "::endgroup"
 }
 
+begingroup "Sanity-check environment"
+
+# Ensure the HOST_TARGET is what it should be.
+if ! rustc -vV | grep -q "^host: $HOST_TARGET\$"; then
+  echo "This runner should be using host target $HOST_TARGET but rustc disagrees:"
+  rustc -vV
+  exit 1
+fi
+
+endgroup
+
 begingroup "Building Miri"
 
 # Global configuration

src/tools/miri/rust-version

@@ -1 +1 @@
-6dd75f0d6802f56564f5f9c947a85ded286d3986
+e0be1a02626abef2878cb7f4aaef7ae409477112

src/tools/miri/src/bin/miri.rs

@@ -29,8 +29,8 @@ use std::num::NonZero;
 use std::ops::Range;
 use std::path::PathBuf;
 use std::str::FromStr;
-use std::sync::{Arc, Once};
 use std::sync::atomic::{AtomicI32, AtomicU32, Ordering};
+use std::sync::{Arc, Once};
 
 use miri::{
     BacktraceStyle, BorrowTrackerMethod, MiriConfig, MiriEntryFnType, ProvenanceMode, RetagFields,
@@ -720,8 +720,8 @@ fn main() {
 
     // Ensure we have parallelism for many-seeds mode.
     if many_seeds.is_some() && !rustc_args.iter().any(|arg| arg.starts_with("-Zthreads=")) {
-        // Clamp to 10 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(10);
+        // Clamp to 20 threads; things get a less efficient beyond that due to lock contention.
+        let threads = std::thread::available_parallelism().map_or(1, |n| n.get()).min(20);
         rustc_args.push(format!("-Zthreads={threads}"));
     }
     let many_seeds =

src/tools/miri/src/helpers.rs

@@ -999,7 +999,20 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
         &'a [OpTy<'tcx>; N]: TryFrom<&'a [OpTy<'tcx>]>,
     {
         self.check_abi_and_shim_symbol_clash(abi, exp_abi, link_name)?;
-        check_arg_count(args)
+
+        if abi.c_variadic {
+            throw_ub_format!(
+                "calling a non-variadic function with a variadic caller-side signature"
+            );
+        }
+        if let Ok(ops) = args.try_into() {
+            return interp_ok(ops);
+        }
+        throw_ub_format!(
+            "incorrect number of arguments for `{link_name}`: got {}, expected {}",
+            args.len(),
+            N
+        )
     }
 
     /// Check shim for variadic function.
@@ -1015,7 +1028,23 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
         &'a [OpTy<'tcx>; N]: TryFrom<&'a [OpTy<'tcx>]>,
     {
         self.check_abi_and_shim_symbol_clash(abi, exp_abi, link_name)?;
-        check_vargarg_fixed_arg_count(link_name, abi, args)
+
+        if !abi.c_variadic {
+            throw_ub_format!(
+                "calling a variadic function with a non-variadic caller-side signature"
+            );
+        }
+        if abi.fixed_count != u32::try_from(N).unwrap() {
+            throw_ub_format!(
+                "incorrect number of fixed arguments for variadic function `{}`: got {}, expected {N}",
+                link_name.as_str(),
+                abi.fixed_count
+            )
+        }
+        if let Some(args) = args.split_first_chunk() {
+            return interp_ok(args);
+        }
+        panic!("mismatch between signature and `args` slice");
     }
 
     /// Mark a machine allocation that was just created as immutable.
@@ -1199,7 +1228,7 @@ impl<'tcx> MiriMachine<'tcx> {
 }
 
 /// Check that the number of args is what we expect.
-pub fn check_arg_count<'a, 'tcx, const N: usize>(
+pub fn check_intrinsic_arg_count<'a, 'tcx, const N: usize>(
     args: &'a [OpTy<'tcx>],
 ) -> InterpResult<'tcx, &'a [OpTy<'tcx>; N]>
 where
@@ -1208,7 +1237,11 @@ where
     if let Ok(ops) = args.try_into() {
         return interp_ok(ops);
     }
-    throw_ub_format!("incorrect number of arguments: got {}, expected {}", args.len(), N)
+    throw_ub_format!(
+        "incorrect number of arguments for intrinsic: got {}, expected {}",
+        args.len(),
+        N
+    )
 }
 
 /// Check that the number of varargs is at least the minimum what we expect.
@@ -1228,34 +1261,6 @@ pub fn check_min_vararg_count<'a, 'tcx, const N: usize>(
     )
 }
 
-/// Check the number of fixed args of a vararg function.
-/// Returns a tuple that consisting of an array of fixed args, and a slice of varargs.
-fn check_vargarg_fixed_arg_count<'a, 'tcx, const N: usize>(
-    link_name: Symbol,
-    abi: &FnAbi<'tcx, Ty<'tcx>>,
-    args: &'a [OpTy<'tcx>],
-) -> InterpResult<'tcx, (&'a [OpTy<'tcx>; N], &'a [OpTy<'tcx>])> {
-    if !abi.c_variadic {
-        throw_ub_format!("calling a variadic function with a non-variadic caller-side signature");
-    }
-    if abi.fixed_count != u32::try_from(N).unwrap() {
-        throw_ub_format!(
-            "incorrect number of fixed arguments for variadic function `{}`: got {}, expected {N}",
-            link_name.as_str(),
-            abi.fixed_count
-        )
-    }
-    if let Some(args) = args.split_first_chunk() {
-        return interp_ok(args);
-    }
-    throw_ub_format!(
-        "incorrect number of arguments for `{}`: got {}, expected at least {}",
-        link_name.as_str(),
-        args.len(),
-        N
-    )
-}
-
 pub fn isolation_abort_error<'tcx>(name: &str) -> InterpResult<'tcx> {
     throw_machine_stop!(TerminationInfo::UnsupportedInIsolation(format!(
         "{name} not available when isolation is enabled",

src/tools/miri/src/intrinsics/atomic.rs

@@ -1,7 +1,7 @@
 use rustc_middle::mir::BinOp;
 use rustc_middle::{mir, ty};
 
-use self::helpers::check_arg_count;
+use self::helpers::check_intrinsic_arg_count;
 use crate::*;
 
 pub enum AtomicOp {
@@ -131,7 +131,7 @@ trait EvalContextPrivExt<'tcx>: MiriInterpCxExt<'tcx> {
     ) -> InterpResult<'tcx> {
         let this = self.eval_context_mut();
 
-        let [place] = check_arg_count(args)?;
+        let [place] = check_intrinsic_arg_count(args)?;
         let place = this.deref_pointer(place)?;
 
         // Perform atomic load.
@@ -144,7 +144,7 @@ trait EvalContextPrivExt<'tcx>: MiriInterpCxExt<'tcx> {
     fn atomic_store(&mut self, args: &[OpTy<'tcx>], atomic: AtomicWriteOrd) -> InterpResult<'tcx> {
         let this = self.eval_context_mut();
 
-        let [place, val] = check_arg_count(args)?;
+        let [place, val] = check_intrinsic_arg_count(args)?;
         let place = this.deref_pointer(place)?;
 
         // Perform regular load.
@@ -159,7 +159,7 @@ trait EvalContextPrivExt<'tcx>: MiriInterpCxExt<'tcx> {
         args: &[OpTy<'tcx>],
         atomic: AtomicFenceOrd,
     ) -> InterpResult<'tcx> {
-        let [] = check_arg_count(args)?;
+        let [] = check_intrinsic_arg_count(args)?;
         let _ = atomic;
         //FIXME: compiler fences are currently ignored
         interp_ok(())
@@ -171,7 +171,7 @@ trait EvalContextPrivExt<'tcx>: MiriInterpCxExt<'tcx> {
         atomic: AtomicFenceOrd,
     ) -> InterpResult<'tcx> {
         let this = self.eval_context_mut();
-        let [] = check_arg_count(args)?;
+        let [] = check_intrinsic_arg_count(args)?;
         this.atomic_fence(atomic)?;
         interp_ok(())
     }
@@ -185,7 +185,7 @@ trait EvalContextPrivExt<'tcx>: MiriInterpCxExt<'tcx> {
     ) -> InterpResult<'tcx> {
         let this = self.eval_context_mut();
 
-        let [place, rhs] = check_arg_count(args)?;
+        let [place, rhs] = check_intrinsic_arg_count(args)?;
         let place = this.deref_pointer(place)?;
         let rhs = this.read_immediate(rhs)?;
 
@@ -226,7 +226,7 @@ trait EvalContextPrivExt<'tcx>: MiriInterpCxExt<'tcx> {
     ) -> InterpResult<'tcx> {
         let this = self.eval_context_mut();
 
-        let [place, new] = check_arg_count(args)?;
+        let [place, new] = check_intrinsic_arg_count(args)?;
         let place = this.deref_pointer(place)?;
         let new = this.read_scalar(new)?;
 
@@ -245,7 +245,7 @@ trait EvalContextPrivExt<'tcx>: MiriInterpCxExt<'tcx> {
     ) -> InterpResult<'tcx> {
         let this = self.eval_context_mut();
 
-        let [place, expect_old, new] = check_arg_count(args)?;
+        let [place, expect_old, new] = check_intrinsic_arg_count(args)?;
         let place = this.deref_pointer(place)?;
         let expect_old = this.read_immediate(expect_old)?; // read as immediate for the sake of `binary_op()`
         let new = this.read_scalar(new)?;