Auto merge of #120451 - RalfJung:miri, r=RalfJung

Miri subtree update

r? `@ghost`

.github/workflows/sysroots.yml

@@ -1,8 +1,8 @@
 name: Tier 2 sysroots
 
-on: push
-#  schedule:
-#    - cron: '44 4 * * *' # At 4:44 UTC every day.
+on:
+  schedule:
+    - cron: '44 4 * * *' # At 4:44 UTC every day.
 
 defaults:
   run:

README.md

@@ -590,6 +590,7 @@ Definite bugs found:
 * [Incorrect use of `compare_exchange_weak` in `once_cell`](https://github.com/matklad/once_cell/issues/186)
 * [Dropping with unaligned pointers in `vec::IntoIter`](https://github.com/rust-lang/rust/pull/106084)
 * [Deallocating with the wrong layout in new specializations for in-place `Iterator::collect`](https://github.com/rust-lang/rust/pull/118460)
+* [Incorrect offset computation for highly-aligned types in `portable-atomic-util`](https://github.com/taiki-e/portable-atomic/pull/138)
 
 Violations of [Stacked Borrows] found that are likely bugs (but Stacked Borrows is currently just an experiment):
 

cargo-miri/src/phases.rs

@@ -501,11 +501,10 @@ pub fn phase_runner(mut binary_args: impl Iterator<Item = String>, phase: Runner
     // Set missing env vars. We prefer build-time env vars over run-time ones; see
     // <https://github.com/rust-lang/miri/issues/1661> for the kind of issue that fixes.
     for (name, val) in info.env {
-        // `CARGO_MAKEFLAGS` contains information about how to reach the
-        // jobserver, but by the time the program is being run, that jobserver
-        // no longer exists. Hence we shouldn't forward this.
-        // FIXME: Miri builds the final crate without a jobserver.
-        // This may be fixed with github.com/rust-lang/cargo/issues/12597.
+        // `CARGO_MAKEFLAGS` contains information about how to reach the jobserver, but by the time
+        // the program is being run, that jobserver no longer exists (cargo only runs the jobserver
+        // for the build portion of `cargo run`/`cargo test`). Hence we shouldn't forward this.
+        // Also see <https://github.com/rust-lang/rust/pull/113730>.
         if name == "CARGO_MAKEFLAGS" {
             continue;
         }

rust-version

@@ -1 +1 @@
-5bcd86d89b2b7b6a490f7e075dd4eb346deb5f98
+dd2559e08e1530806740931037d6bb83ef956161

src/helpers.rs

@@ -217,7 +217,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
 
     /// Helper function to get a `windows` constant as a `Scalar`.
     fn eval_windows(&self, module: &str, name: &str) -> Scalar<Provenance> {
-        self.eval_context_ref().eval_path_scalar(&["std", "sys", "pal","windows", module, name])
+        self.eval_context_ref().eval_path_scalar(&["std", "sys", "pal", "windows", module, name])
     }
 
     /// Helper function to get a `windows` constant as a `u32`.
@@ -249,7 +249,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
     fn windows_ty_layout(&self, name: &str) -> TyAndLayout<'tcx> {
         let this = self.eval_context_ref();
         let ty = this
-            .resolve_path(&["std", "sys", "pal","windows", "c", name], Namespace::TypeNS)
+            .resolve_path(&["std", "sys", "pal", "windows", "c", name], Namespace::TypeNS)
             .ty(*this.tcx, ty::ParamEnv::reveal_all());
         this.layout_of(ty).unwrap()
     }
@@ -270,6 +270,21 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
         bug!("No field named {} in type {}", name, base.layout().ty);
     }
 
+    /// Search if `base` (which must be a struct or union type) contains the `name` field.
+    fn projectable_has_field<P: Projectable<'tcx, Provenance>>(
+        &self,
+        base: &P,
+        name: &str,
+    ) -> bool {
+        let adt = base.layout().ty.ty_adt_def().unwrap();
+        for field in adt.non_enum_variant().fields.iter() {
+            if field.name.as_str() == name {
+                return true;
+            }
+        }
+        false
+    }
+
     /// Write an int of the appropriate size to `dest`. The target type may be signed or unsigned,
     /// we try to do the right thing anyway. `i128` can fit all integer types except for `u128` so
     /// this method is fine for almost all integer types.

src/lib.rs

@@ -94,7 +94,6 @@ pub use crate::shims::os_str::EvalContextExt as _;
 pub use crate::shims::panic::{CatchUnwindData, EvalContextExt as _};
 pub use crate::shims::time::EvalContextExt as _;
 pub use crate::shims::tls::TlsData;
-pub use crate::shims::EvalContextExt as _;
 
 pub use crate::borrow_tracker::stacked_borrows::{
     EvalContextExt as _, Item, Permission, Stack, Stacks,

src/machine.rs

@@ -10,8 +10,8 @@ use std::process;
 
 use either::Either;
 use rand::rngs::StdRng;
-use rand::SeedableRng;
 use rand::Rng;
+use rand::SeedableRng;
 
 use rustc_ast::ast::Mutability;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
@@ -83,7 +83,8 @@ pub struct FrameExtra<'tcx> {
 impl<'tcx> std::fmt::Debug for FrameExtra<'tcx> {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         // Omitting `timing`, it does not support `Debug`.
-        let FrameExtra { borrow_tracker, catch_unwind, timing: _, is_user_relevant: _, salt: _ } = self;
+        let FrameExtra { borrow_tracker, catch_unwind, timing: _, is_user_relevant: _, salt: _ } =
+            self;
         f.debug_struct("FrameData")
             .field("borrow_tracker", borrow_tracker)
             .field("catch_unwind", catch_unwind)
@@ -93,7 +94,8 @@ impl<'tcx> std::fmt::Debug for FrameExtra<'tcx> {
 
 impl VisitProvenance for FrameExtra<'_> {
     fn visit_provenance(&self, visit: &mut VisitWith<'_>) {
-        let FrameExtra { catch_unwind, borrow_tracker, timing: _, is_user_relevant: _, salt: _ } = self;
+        let FrameExtra { catch_unwind, borrow_tracker, timing: _, is_user_relevant: _, salt: _ } =
+            self;
 
         catch_unwind.visit_provenance(visit);
         borrow_tracker.visit_provenance(visit);
@@ -710,7 +712,7 @@ impl<'mir, 'tcx> MiriMachine<'mir, 'tcx> {
         Ok(())
     }
 
-    fn add_extern_static(
+    pub(crate) fn add_extern_static(
         this: &mut MiriInterpCx<'mir, 'tcx>,
         name: &str,
         ptr: Pointer<Option<Provenance>>,
@@ -720,75 +722,6 @@ impl<'mir, 'tcx> MiriMachine<'mir, 'tcx> {
         this.machine.extern_statics.try_insert(Symbol::intern(name), ptr).unwrap();
     }
 
-    fn alloc_extern_static(
-        this: &mut MiriInterpCx<'mir, 'tcx>,
-        name: &str,
-        val: ImmTy<'tcx, Provenance>,
-    ) -> InterpResult<'tcx> {
-        let place = this.allocate(val.layout, MiriMemoryKind::ExternStatic.into())?;
-        this.write_immediate(*val, &place)?;
-        Self::add_extern_static(this, name, place.ptr());
-        Ok(())
-    }
-
-    /// Sets up the "extern statics" for this machine.
-    fn init_extern_statics(this: &mut MiriInterpCx<'mir, 'tcx>) -> InterpResult<'tcx> {
-        // "__rust_no_alloc_shim_is_unstable"
-        let val = ImmTy::from_int(0, this.machine.layouts.u8);
-        Self::alloc_extern_static(this, "__rust_no_alloc_shim_is_unstable", val)?;
-
-        match this.tcx.sess.target.os.as_ref() {
-            "linux" => {
-                // "environ"
-                Self::add_extern_static(
-                    this,
-                    "environ",
-                    this.machine.env_vars.environ.as_ref().unwrap().ptr(),
-                );
-                // A couple zero-initialized pointer-sized extern statics.
-                // Most of them are for weak symbols, which we all set to null (indicating that the
-                // symbol is not supported, and triggering fallback code which ends up calling a
-                // syscall that we do support).
-                for name in &["__cxa_thread_atexit_impl", "getrandom", "statx", "__clock_gettime64"]
-                {
-                    let val = ImmTy::from_int(0, this.machine.layouts.usize);
-                    Self::alloc_extern_static(this, name, val)?;
-                }
-            }
-            "freebsd" => {
-                // "environ"
-                Self::add_extern_static(
-                    this,
-                    "environ",
-                    this.machine.env_vars.environ.as_ref().unwrap().ptr(),
-                );
-            }
-            "android" => {
-                // "signal" -- just needs a non-zero pointer value (function does not even get called),
-                // but we arrange for this to be callable anyway (it will then do nothing).
-                let layout = this.machine.layouts.const_raw_ptr;
-                let ptr = this.fn_ptr(FnVal::Other(DynSym::from_str("signal")));
-                let val = ImmTy::from_scalar(Scalar::from_pointer(ptr, this), layout);
-                Self::alloc_extern_static(this, "signal", val)?;
-                // A couple zero-initialized pointer-sized extern statics.
-                // Most of them are for weak symbols, which we all set to null (indicating that the
-                // symbol is not supported, and triggering fallback code.)
-                for name in &["bsd_signal"] {
-                    let val = ImmTy::from_int(0, this.machine.layouts.usize);
-                    Self::alloc_extern_static(this, name, val)?;
-                }
-            }
-            "windows" => {
-                // "_tls_used"
-                // This is some obscure hack that is part of the Windows TLS story. It's a `u8`.
-                let val = ImmTy::from_int(0, this.machine.layouts.u8);
-                Self::alloc_extern_static(this, "_tls_used", val)?;
-            }
-            _ => {} // No "extern statics" supported on this target
-        }
-        Ok(())
-    }
-
     pub(crate) fn communicate(&self) -> bool {
         self.isolated_op == IsolatedOp::Allow
     }
@@ -1009,7 +942,21 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for MiriMachine<'mir, 'tcx> {
         ret: Option<mir::BasicBlock>,
         unwind: mir::UnwindAction,
     ) -> InterpResult<'tcx, Option<(&'mir mir::Body<'tcx>, ty::Instance<'tcx>)>> {
-        ecx.find_mir_or_eval_fn(instance, abi, args, dest, ret, unwind)
+        // For foreign items, try to see if we can emulate them.
+        if ecx.tcx.is_foreign_item(instance.def_id()) {
+            // An external function call that does not have a MIR body. We either find MIR elsewhere
+            // or emulate its effect.
+            // This will be Ok(None) if we're emulating the intrinsic entirely within Miri (no need
+            // to run extra MIR), and Ok(Some(body)) if we found MIR to run for the
+            // foreign function
+            // Any needed call to `goto_block` will be performed by `emulate_foreign_item`.
+            let args = ecx.copy_fn_args(args)?; // FIXME: Should `InPlace` arguments be reset to uninit?
+            let link_name = ecx.item_link_name(instance.def_id());
+            return ecx.emulate_foreign_item(link_name, abi, &args, dest, ret, unwind);
+        }
+
+        // Otherwise, load the MIR.
+        Ok(Some((ecx.load_mir(instance.def, None)?, instance)))
     }
 
     #[inline(always)]

src/operator.rs

@@ -24,7 +24,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
 
         Ok(match bin_op {
             Eq | Ne | Lt | Le | Gt | Ge => {
-                assert_eq!(left.layout.abi, right.layout.abi); // types an differ, e.g. fn ptrs with different `for`
+                assert_eq!(left.layout.abi, right.layout.abi); // types can differ, e.g. fn ptrs with different `for`
                 let size = this.pointer_size();
                 // Just compare the bits. ScalarPairs are compared lexicographically.
                 // We thus always compare pairs and simply fill scalars up with 0.

src/shims/extern_static.rs

@@ -0,0 +1,79 @@
+//! Provides the `extern static` that this platform expects.
+
+use crate::*;
+
+impl<'mir, 'tcx> MiriMachine<'mir, 'tcx> {
+    fn alloc_extern_static(
+        this: &mut MiriInterpCx<'mir, 'tcx>,
+        name: &str,
+        val: ImmTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx> {
+        let place = this.allocate(val.layout, MiriMemoryKind::ExternStatic.into())?;
+        this.write_immediate(*val, &place)?;
+        Self::add_extern_static(this, name, place.ptr());
+        Ok(())
+    }
+
+    /// Zero-initialized pointer-sized extern statics are pretty common.
+    /// Most of them are for weak symbols, which we all set to null (indicating that the
+    /// symbol is not supported, and triggering fallback code which ends up calling a
+    /// syscall that we do support).
+    fn null_ptr_extern_statics(
+        this: &mut MiriInterpCx<'mir, 'tcx>,
+        names: &[&str],
+    ) -> InterpResult<'tcx> {
+        for name in names {
+            let val = ImmTy::from_int(0, this.machine.layouts.usize);
+            Self::alloc_extern_static(this, name, val)?;
+        }
+        Ok(())
+    }
+
+    /// Sets up the "extern statics" for this machine.
+    pub fn init_extern_statics(this: &mut MiriInterpCx<'mir, 'tcx>) -> InterpResult<'tcx> {
+        // "__rust_no_alloc_shim_is_unstable"
+        let val = ImmTy::from_int(0, this.machine.layouts.u8);
+        Self::alloc_extern_static(this, "__rust_no_alloc_shim_is_unstable", val)?;
+
+        match this.tcx.sess.target.os.as_ref() {
+            "linux" => {
+                Self::null_ptr_extern_statics(
+                    this,
+                    &["__cxa_thread_atexit_impl", "getrandom", "statx", "__clock_gettime64"],
+                )?;
+                // "environ"
+                Self::add_extern_static(
+                    this,
+                    "environ",
+                    this.machine.env_vars.environ.as_ref().unwrap().ptr(),
+                );
+            }
+            "freebsd" => {
+                Self::null_ptr_extern_statics(this, &["__cxa_thread_atexit_impl"])?;
+                // "environ"
+                Self::add_extern_static(
+                    this,
+                    "environ",
+                    this.machine.env_vars.environ.as_ref().unwrap().ptr(),
+                );
+            }
+            "android" => {
+                Self::null_ptr_extern_statics(this, &["bsd_signal"])?;
+                // "signal" -- just needs a non-zero pointer value (function does not even get called),
+                // but we arrange for this to call the `signal` function anyway.
+                let layout = this.machine.layouts.const_raw_ptr;
+                let ptr = this.fn_ptr(FnVal::Other(DynSym::from_str("signal")));
+                let val = ImmTy::from_scalar(Scalar::from_pointer(ptr, this), layout);
+                Self::alloc_extern_static(this, "signal", val)?;
+            }
+            "windows" => {
+                // "_tls_used"
+                // This is some obscure hack that is part of the Windows TLS story. It's a `u8`.
+                let val = ImmTy::from_int(0, this.machine.layouts.u8);
+                Self::alloc_extern_static(this, "_tls_used", val)?;
+            }
+            _ => {} // No "extern statics" supported on this target
+        }
+        Ok(())
+    }
+}

src/shims/intrinsics/mod.rs

@@ -148,7 +148,8 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
             // ```
             // Would not be considered UB, or the other way around (`is_val_statically_known(0)`).
             "is_val_statically_known" => {
-                let [_] = check_arg_count(args)?;
+                let [arg] = check_arg_count(args)?;
+                this.validate_operand(arg)?;
                 let branch: bool = this.machine.rng.get_mut().gen();
                 this.write_scalar(Scalar::from_bool(branch), dest)?;
             }

src/shims/mod.rs

@@ -10,48 +10,8 @@ pub mod windows;
 mod x86;
 
 pub mod env;
+pub mod extern_static;
 pub mod os_str;
 pub mod panic;
 pub mod time;
 pub mod tls;
-
-// End module management, begin local code
-
-use log::trace;
-
-use rustc_middle::{mir, ty};
-use rustc_target::spec::abi::Abi;
-
-use crate::*;
-
-impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
-pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
-    fn find_mir_or_eval_fn(
-        &mut self,
-        instance: ty::Instance<'tcx>,
-        abi: Abi,
-        args: &[FnArg<'tcx, Provenance>],
-        dest: &PlaceTy<'tcx, Provenance>,
-        ret: Option<mir::BasicBlock>,
-        unwind: mir::UnwindAction,
-    ) -> InterpResult<'tcx, Option<(&'mir mir::Body<'tcx>, ty::Instance<'tcx>)>> {
-        let this = self.eval_context_mut();
-        trace!("eval_fn_call: {:#?}, {:?}", instance, dest);
-
-        // For foreign items, try to see if we can emulate them.
-        if this.tcx.is_foreign_item(instance.def_id()) {
-            // An external function call that does not have a MIR body. We either find MIR elsewhere
-            // or emulate its effect.
-            // This will be Ok(None) if we're emulating the intrinsic entirely within Miri (no need
-            // to run extra MIR), and Ok(Some(body)) if we found MIR to run for the
-            // foreign function
-            // Any needed call to `goto_block` will be performed by `emulate_foreign_item`.
-            let args = this.copy_fn_args(args)?; // FIXME: Should `InPlace` arguments be reset to uninit?
-            let link_name = this.item_link_name(instance.def_id());
-            return this.emulate_foreign_item(link_name, abi, &args, dest, ret, unwind);
-        }
-
-        // Otherwise, load the MIR.
-        Ok(Some((this.load_mir(instance.def, None)?, instance)))
-    }
-}