Rollup merge of #128687 - RalfJung:interpret-call-refactor, r=WaffleLapkin

interpret: refactor function call handling to be better-abstracted

Add a new function `init_stack_frame` that pushes a stack frame and passes the arguments, and use that basically everywhere that the raw underlying `push_stack_frame` used to be called. This splits the previous monster function `eval_fn_call` into two parts: figuring out the MIR to call and the arguments to pass, and then actually setting up the stack frame.

Also re-organize the files a bit:
- The previous `terminator.rs` is split into a new `call.rs` with all the argument-passing logic, and the rest goes into `step.rs` where the other main dispatcher functions already live (in particular, `eval_statement`).
- All the stack frame handling from `eval_context.rs` is moved to a new `stack.rs`.

Author: matthiaskrgr

compiler/rustc_const_eval/src/const_eval/eval_queries.rs

@@ -73,7 +73,9 @@ fn eval_body_using_ecx<'tcx, R: InterpretationResult<'tcx>>(
         cid.promoted.map_or_else(String::new, |p| format!("::{p:?}"))
     );
 
-    ecx.push_stack_frame(
+    // This can't use `init_stack_frame` since `body` is not a function,
+    // so computing its ABI would fail. It's also not worth it since there are no arguments to pass.
+    ecx.push_stack_frame_raw(
         cid.instance,
         body,
         &ret.clone().into(),

compiler/rustc_const_eval/src/const_eval/machine.rs

@@ -24,8 +24,9 @@ use crate::errors::{LongRunning, LongRunningWarn};
 use crate::fluent_generated as fluent;
 use crate::interpret::{
     self, compile_time_machine, err_ub, throw_exhaust, throw_inval, throw_ub_custom, throw_unsup,
-    throw_unsup_format, AllocId, AllocRange, ConstAllocation, CtfeProvenance, FnArg, FnVal, Frame,
+    throw_unsup_format, AllocId, AllocRange, ConstAllocation, CtfeProvenance, FnArg, Frame,
     GlobalAlloc, ImmTy, InterpCx, InterpResult, MPlaceTy, OpTy, Pointer, PointerArithmetic, Scalar,
+    StackPopCleanup,
 };
 
 /// When hitting this many interpreted terminators we emit a deny by default lint
@@ -306,17 +307,15 @@ impl<'tcx> CompileTimeInterpCx<'tcx> {
                     let align = ImmTy::from_uint(target_align, args[1].layout).into();
                     let fn_abi = self.fn_abi_of_instance(instance, ty::List::empty())?;
 
-                    // We replace the entire function call with a "tail call".
-                    // Note that this happens before the frame of the original function
-                    // is pushed on the stack.
-                    self.eval_fn_call(
-                        FnVal::Instance(instance),
-                        (CallAbi::Rust, fn_abi),
+                    // Push the stack frame with our own adjusted arguments.
+                    self.init_stack_frame(
+                        instance,
+                        self.load_mir(instance.def, None)?,
+                        fn_abi,
                         &[FnArg::Copy(addr), FnArg::Copy(align)],
                         /* with_caller_location = */ false,
                         dest,
-                        ret,
-                        mir::UnwindAction::Unreachable,
+                        StackPopCleanup::Goto { ret, unwind: mir::UnwindAction::Unreachable },
                     )?;
                     Ok(ControlFlow::Break(()))
                 } else {

compiler/rustc_const_eval/src/interpret/terminator.rs renamed to compiler/rustc_const_eval/src/interpret/call.rs

@@ -37,7 +37,7 @@ pub enum ReturnAction {
     /// took care of everything.
     NoJump,
 
-    /// Returned by [`InterpCx::pop_stack_frame`] when no cleanup should be done.
+    /// Returned by [`InterpCx::pop_stack_frame_raw`] when no cleanup should be done.
     NoCleanup,
 }
 

compiler/rustc_const_eval/src/interpret/eval_context.rs

@@ -1,5 +1,6 @@
 //! An interpreter for MIR used in CTFE and by miri
 
+mod call;
 mod cast;
 mod discriminant;
 mod eval_context;
@@ -11,8 +12,8 @@ mod operand;
 mod operator;
 mod place;
 mod projection;
+mod stack;
 mod step;
-mod terminator;
 mod traits;
 mod util;
 mod validity;
@@ -22,7 +23,8 @@ use eval_context::{from_known_layout, mir_assign_valid_types};
 #[doc(no_inline)]
 pub use rustc_middle::mir::interpret::*; // have all the `interpret` symbols in one place: here
 
-pub use self::eval_context::{format_interp_error, Frame, FrameInfo, InterpCx, StackPopCleanup};
+pub use self::call::FnArg;
+pub use self::eval_context::{format_interp_error, InterpCx};
 pub use self::intern::{
     intern_const_alloc_for_constprop, intern_const_alloc_recursive, HasStaticRootDefId, InternKind,
     InternResult,
@@ -35,7 +37,7 @@ pub use self::operand::{ImmTy, Immediate, OpTy, Readable};
 pub use self::place::{MPlaceTy, MemPlaceMeta, PlaceTy, Writeable};
 use self::place::{MemPlace, Place};
 pub use self::projection::{OffsetMode, Projectable};
-pub use self::terminator::FnArg;
+pub use self::stack::{Frame, FrameInfo, LocalState, StackPopCleanup, StackPopInfo};
 pub(crate) use self::util::create_static_alloc;
 pub use self::validity::{CtfeValidationMode, RefTracking};
 pub use self::visitor::ValueVisitor;

compiler/rustc_const_eval/src/interpret/machine.rs

@@ -184,6 +184,7 @@ impl<'tcx, Prov: Provenance> ImmTy<'tcx, Prov> {
     #[inline]
     pub fn from_scalar(val: Scalar<Prov>, layout: TyAndLayout<'tcx>) -> Self {
         debug_assert!(layout.abi.is_scalar(), "`ImmTy::from_scalar` on non-scalar layout");
+        debug_assert_eq!(val.size(), layout.size);
         ImmTy { imm: val.into(), layout }
     }
 

compiler/rustc_const_eval/src/interpret/mod.rs

@@ -4,15 +4,29 @@
 
 use either::Either;
 use rustc_index::IndexSlice;
-use rustc_middle::{bug, mir};
+use rustc_middle::ty::layout::FnAbiOf;
+use rustc_middle::ty::{self, Instance, Ty};
+use rustc_middle::{bug, mir, span_bug};
+use rustc_span::source_map::Spanned;
+use rustc_target::abi::call::FnAbi;
 use rustc_target::abi::{FieldIdx, FIRST_VARIANT};
 use tracing::{info, instrument, trace};
 
 use super::{
-    ImmTy, Immediate, InterpCx, InterpResult, Machine, MemPlaceMeta, PlaceTy, Projectable, Scalar,
+    throw_ub, FnArg, FnVal, ImmTy, Immediate, InterpCx, InterpResult, Machine, MemPlaceMeta,
+    PlaceTy, Projectable, Scalar,
 };
 use crate::util;
 
+struct EvaluatedCalleeAndArgs<'tcx, M: Machine<'tcx>> {
+    callee: FnVal<'tcx, M::ExtraFnVal>,
+    args: Vec<FnArg<'tcx, M::Provenance>>,
+    fn_sig: ty::FnSig<'tcx>,
+    fn_abi: &'tcx FnAbi<'tcx, Ty<'tcx>>,
+    /// True if the function is marked as `#[track_caller]` ([`ty::InstanceKind::requires_caller_location`])
+    with_caller_location: bool,
+}
+
 impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
     /// Returns `true` as long as there are more things to do.
     ///
@@ -36,7 +50,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
 
         if let Some(stmt) = basic_block.statements.get(loc.statement_index) {
             let old_frames = self.frame_idx();
-            self.statement(stmt)?;
+            self.eval_statement(stmt)?;
             // Make sure we are not updating `statement_index` of the wrong frame.
             assert_eq!(old_frames, self.frame_idx());
             // Advance the program counter.
@@ -47,15 +61,20 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
         M::before_terminator(self)?;
 
         let terminator = basic_block.terminator();
-        self.terminator(terminator)?;
+        self.eval_terminator(terminator)?;
+        if !self.stack().is_empty() {
+            if let Either::Left(loc) = self.frame().loc {
+                info!("// executing {:?}", loc.block);
+            }
+        }
         Ok(true)
     }
 
     /// Runs the interpretation logic for the given `mir::Statement` at the current frame and
     /// statement counter.
     ///
     /// This does NOT move the statement counter forward, the caller has to do that!
-    pub fn statement(&mut self, stmt: &mir::Statement<'tcx>) -> InterpResult<'tcx> {
+    pub fn eval_statement(&mut self, stmt: &mir::Statement<'tcx>) -> InterpResult<'tcx> {
         info!("{:?}", stmt);
 
         use rustc_middle::mir::StatementKind::*;
@@ -349,16 +368,222 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
         Ok(())
     }
 
-    /// Evaluate the given terminator. Will also adjust the stack frame and statement position accordingly.
-    fn terminator(&mut self, terminator: &mir::Terminator<'tcx>) -> InterpResult<'tcx> {
+    /// Evaluate the arguments of a function call
+    fn eval_fn_call_argument(
+        &self,
+        op: &mir::Operand<'tcx>,
+    ) -> InterpResult<'tcx, FnArg<'tcx, M::Provenance>> {
+        Ok(match op {
+            mir::Operand::Copy(_) | mir::Operand::Constant(_) => {
+                // Make a regular copy.
+                let op = self.eval_operand(op, None)?;
+                FnArg::Copy(op)
+            }
+            mir::Operand::Move(place) => {
+                // If this place lives in memory, preserve its location.
+                // We call `place_to_op` which will be an `MPlaceTy` whenever there exists
+                // an mplace for this place. (This is in contrast to `PlaceTy::as_mplace_or_local`
+                // which can return a local even if that has an mplace.)
+                let place = self.eval_place(*place)?;
+                let op = self.place_to_op(&place)?;
+
+                match op.as_mplace_or_imm() {
+                    Either::Left(mplace) => FnArg::InPlace(mplace),
+                    Either::Right(_imm) => {
+                        // This argument doesn't live in memory, so there's no place
+                        // to make inaccessible during the call.
+                        // We rely on there not being any stray `PlaceTy` that would let the
+                        // caller directly access this local!
+                        // This is also crucial for tail calls, where we want the `FnArg` to
+                        // stay valid when the old stack frame gets popped.
+                        FnArg::Copy(op)
+                    }
+                }
+            }
+        })
+    }
+
+    /// Shared part of `Call` and `TailCall` implementation — finding and evaluating all the
+    /// necessary information about callee and arguments to make a call.
+    fn eval_callee_and_args(
+        &self,
+        terminator: &mir::Terminator<'tcx>,
+        func: &mir::Operand<'tcx>,
+        args: &[Spanned<mir::Operand<'tcx>>],
+    ) -> InterpResult<'tcx, EvaluatedCalleeAndArgs<'tcx, M>> {
+        let func = self.eval_operand(func, None)?;
+        let args = args
+            .iter()
+            .map(|arg| self.eval_fn_call_argument(&arg.node))
+            .collect::<InterpResult<'tcx, Vec<_>>>()?;
+
+        let fn_sig_binder = func.layout.ty.fn_sig(*self.tcx);
+        let fn_sig = self.tcx.normalize_erasing_late_bound_regions(self.param_env, fn_sig_binder);
+        let extra_args = &args[fn_sig.inputs().len()..];
+        let extra_args =
+            self.tcx.mk_type_list_from_iter(extra_args.iter().map(|arg| arg.layout().ty));
+
+        let (callee, fn_abi, with_caller_location) = match *func.layout.ty.kind() {
+            ty::FnPtr(_sig) => {
+                let fn_ptr = self.read_pointer(&func)?;
+                let fn_val = self.get_ptr_fn(fn_ptr)?;
+                (fn_val, self.fn_abi_of_fn_ptr(fn_sig_binder, extra_args)?, false)
+            }
+            ty::FnDef(def_id, args) => {
+                let instance = self.resolve(def_id, args)?;
+                (
+                    FnVal::Instance(instance),
+                    self.fn_abi_of_instance(instance, extra_args)?,
+                    instance.def.requires_caller_location(*self.tcx),
+                )
+            }
+            _ => {
+                span_bug!(terminator.source_info.span, "invalid callee of type {}", func.layout.ty)
+            }
+        };
+
+        Ok(EvaluatedCalleeAndArgs { callee, args, fn_sig, fn_abi, with_caller_location })
+    }
+
+    fn eval_terminator(&mut self, terminator: &mir::Terminator<'tcx>) -> InterpResult<'tcx> {
         info!("{:?}", terminator.kind);
 
-        self.eval_terminator(terminator)?;
-        if !self.stack().is_empty() {
-            if let Either::Left(loc) = self.frame().loc {
-                info!("// executing {:?}", loc.block);
+        use rustc_middle::mir::TerminatorKind::*;
+        match terminator.kind {
+            Return => {
+                self.return_from_current_stack_frame(/* unwinding */ false)?
+            }
+
+            Goto { target } => self.go_to_block(target),
+
+            SwitchInt { ref discr, ref targets } => {
+                let discr = self.read_immediate(&self.eval_operand(discr, None)?)?;
+                trace!("SwitchInt({:?})", *discr);
+
+                // Branch to the `otherwise` case by default, if no match is found.
+                let mut target_block = targets.otherwise();
+
+                for (const_int, target) in targets.iter() {
+                    // Compare using MIR BinOp::Eq, to also support pointer values.
+                    // (Avoiding `self.binary_op` as that does some redundant layout computation.)
+                    let res = self.binary_op(
+                        mir::BinOp::Eq,
+                        &discr,
+                        &ImmTy::from_uint(const_int, discr.layout),
+                    )?;
+                    if res.to_scalar().to_bool()? {
+                        target_block = target;
+                        break;
+                    }
+                }
+
+                self.go_to_block(target_block);
+            }
+
+            Call {
+                ref func,
+                ref args,
+                destination,
+                target,
+                unwind,
+                call_source: _,
+                fn_span: _,
+            } => {
+                let old_stack = self.frame_idx();
+                let old_loc = self.frame().loc;
+
+                let EvaluatedCalleeAndArgs { callee, args, fn_sig, fn_abi, with_caller_location } =
+                    self.eval_callee_and_args(terminator, func, args)?;
+
+                let destination = self.force_allocation(&self.eval_place(destination)?)?;
+                self.init_fn_call(
+                    callee,
+                    (fn_sig.abi, fn_abi),
+                    &args,
+                    with_caller_location,
+                    &destination,
+                    target,
+                    if fn_abi.can_unwind { unwind } else { mir::UnwindAction::Unreachable },
+                )?;
+                // Sanity-check that `eval_fn_call` either pushed a new frame or
+                // did a jump to another block.
+                if self.frame_idx() == old_stack && self.frame().loc == old_loc {
+                    span_bug!(terminator.source_info.span, "evaluating this call made no progress");
+                }
+            }
+
+            TailCall { ref func, ref args, fn_span: _ } => {
+                let old_frame_idx = self.frame_idx();
+
+                let EvaluatedCalleeAndArgs { callee, args, fn_sig, fn_abi, with_caller_location } =
+                    self.eval_callee_and_args(terminator, func, args)?;
+
+                self.init_fn_tail_call(callee, (fn_sig.abi, fn_abi), &args, with_caller_location)?;
+
+                if self.frame_idx() != old_frame_idx {
+                    span_bug!(
+                        terminator.source_info.span,
+                        "evaluating this tail call pushed a new stack frame"
+                    );
+                }
+            }
+
+            Drop { place, target, unwind, replace: _ } => {
+                let place = self.eval_place(place)?;
+                let instance = Instance::resolve_drop_in_place(*self.tcx, place.layout.ty);
+                if let ty::InstanceKind::DropGlue(_, None) = instance.def {
+                    // This is the branch we enter if and only if the dropped type has no drop glue
+                    // whatsoever. This can happen as a result of monomorphizing a drop of a
+                    // generic. In order to make sure that generic and non-generic code behaves
+                    // roughly the same (and in keeping with Mir semantics) we do nothing here.
+                    self.go_to_block(target);
+                    return Ok(());
+                }
+                trace!("TerminatorKind::drop: {:?}, type {}", place, place.layout.ty);
+                self.init_drop_in_place_call(&place, instance, target, unwind)?;
+            }
+
+            Assert { ref cond, expected, ref msg, target, unwind } => {
+                let ignored =
+                    M::ignore_optional_overflow_checks(self) && msg.is_optional_overflow_check();
+                let cond_val = self.read_scalar(&self.eval_operand(cond, None)?)?.to_bool()?;
+                if ignored || expected == cond_val {
+                    self.go_to_block(target);
+                } else {
+                    M::assert_panic(self, msg, unwind)?;
+                }
+            }
+
+            UnwindTerminate(reason) => {
+                M::unwind_terminate(self, reason)?;
+            }
+
+            // When we encounter Resume, we've finished unwinding
+            // cleanup for the current stack frame. We pop it in order
+            // to continue unwinding the next frame
+            UnwindResume => {
+                trace!("unwinding: resuming from cleanup");
+                // By definition, a Resume terminator means
+                // that we're unwinding
+                self.return_from_current_stack_frame(/* unwinding */ true)?;
+                return Ok(());
+            }
+
+            // It is UB to ever encounter this.
+            Unreachable => throw_ub!(Unreachable),
+
+            // These should never occur for MIR we actually run.
+            FalseEdge { .. } | FalseUnwind { .. } | Yield { .. } | CoroutineDrop => span_bug!(
+                terminator.source_info.span,
+                "{:#?} should have been eliminated by MIR pass",
+                terminator.kind
+            ),
+
+            InlineAsm { template, ref operands, options, ref targets, .. } => {
+                M::eval_inline_asm(self, template, operands, options, targets)?;
             }
         }
+
         Ok(())
     }
 }

compiler/rustc_const_eval/src/interpret/operand.rs

@@ -256,7 +256,7 @@ pub struct Thread<'tcx> {
     /// which then forwards it to 'Resume'. However this argument is implicit in MIR,
     /// so we have to store it out-of-band. When there are multiple active unwinds,
     /// the innermost one is always caught first, so we can store them as a stack.
-    pub(crate) panic_payloads: Vec<Scalar>,
+    pub(crate) panic_payloads: Vec<ImmTy<'tcx>>,
 
     /// Last OS error location in memory. It is a 32-bit integer.
     pub(crate) last_error: Option<MPlaceTy<'tcx>>,
@@ -377,10 +377,6 @@ impl VisitProvenance for Frame<'_, Provenance, FrameExtra<'_>> {
             return_place,
             locals,
             extra,
-            body: _,
-            instance: _,
-            return_to_block: _,
-            loc: _,
             // There are some private fields we cannot access; they contain no tags.
             ..
         } = self;
@@ -952,7 +948,7 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
         this.call_function(
             instance,
             start_abi,
-            &[*func_arg],
+            &[func_arg],
             Some(&ret_place),
             StackPopCleanup::Root { cleanup: true },
         )?;

compiler/rustc_const_eval/src/interpret/stack.rs

@@ -307,7 +307,8 @@ pub fn create_ecx<'tcx>(
     // First argument is constructed later, because it's skipped if the entry function uses #[start].
 
     // Second argument (argc): length of `config.args`.
-    let argc = Scalar::from_target_usize(u64::try_from(config.args.len()).unwrap(), &ecx);
+    let argc =
+        ImmTy::from_int(i64::try_from(config.args.len()).unwrap(), ecx.machine.layouts.isize);
     // Third argument (`argv`): created from `config.args`.
     let argv = {
         // Put each argument in memory, collect pointers.
@@ -334,21 +335,19 @@ pub fn create_ecx<'tcx>(
             ecx.write_immediate(arg, &place)?;
         }
         ecx.mark_immutable(&argvs_place);
-        // A pointer to that place is the 3rd argument for main.
-        let argv = argvs_place.to_ref(&ecx);
         // Store `argc` and `argv` for macOS `_NSGetArg{c,v}`.
         {
             let argc_place =
                 ecx.allocate(ecx.machine.layouts.isize, MiriMemoryKind::Machine.into())?;
-            ecx.write_scalar(argc, &argc_place)?;
+            ecx.write_immediate(*argc, &argc_place)?;
             ecx.mark_immutable(&argc_place);
             ecx.machine.argc = Some(argc_place.ptr());
 
             let argv_place = ecx.allocate(
                 ecx.layout_of(Ty::new_imm_ptr(tcx, tcx.types.unit))?,
                 MiriMemoryKind::Machine.into(),
             )?;
-            ecx.write_immediate(argv, &argv_place)?;
+            ecx.write_pointer(argvs_place.ptr(), &argv_place)?;
             ecx.mark_immutable(&argv_place);
             ecx.machine.argv = Some(argv_place.ptr());
         }
@@ -369,7 +368,7 @@ pub fn create_ecx<'tcx>(
             }
             ecx.mark_immutable(&cmd_place);
         }
-        argv
+        ecx.mplace_to_ref(&argvs_place)?
     };
 
     // Return place (in static memory so that it does not count as leak).
@@ -405,10 +404,14 @@ pub fn create_ecx<'tcx>(
                 start_instance,
                 Abi::Rust,
                 &[
-                    Scalar::from_pointer(main_ptr, &ecx).into(),
-                    argc.into(),
+                    ImmTy::from_scalar(
+                        Scalar::from_pointer(main_ptr, &ecx),
+                        // FIXME use a proper fn ptr type
+                        ecx.machine.layouts.const_raw_ptr,
+                    ),
+                    argc,
                     argv,
-                    Scalar::from_u8(sigpipe).into(),
+                    ImmTy::from_uint(sigpipe, ecx.machine.layouts.u8),
                 ],
                 Some(&ret_place),
                 StackPopCleanup::Root { cleanup: true },
@@ -418,7 +421,7 @@ pub fn create_ecx<'tcx>(
             ecx.call_function(
                 entry_instance,
                 Abi::Rust,
-                &[argc.into(), argv],
+                &[argc, argv],
                 Some(&ret_place),
                 StackPopCleanup::Root { cleanup: true },
             )?;

compiler/rustc_const_eval/src/interpret/step.rs

@@ -12,13 +12,14 @@ use rustc_apfloat::Float;
 use rustc_hir::{
     def::{DefKind, Namespace},
     def_id::{CrateNum, DefId, CRATE_DEF_INDEX, LOCAL_CRATE},
+    Safety,
 };
 use rustc_index::IndexVec;
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use rustc_middle::middle::dependency_format::Linkage;
 use rustc_middle::middle::exported_symbols::ExportedSymbol;
 use rustc_middle::mir;
-use rustc_middle::ty::layout::MaybeResult;
+use rustc_middle::ty::layout::{FnAbiOf, MaybeResult};
 use rustc_middle::ty::{
     self,
     layout::{LayoutOf, TyAndLayout},
@@ -492,48 +493,38 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
         &mut self,
         f: ty::Instance<'tcx>,
         caller_abi: Abi,
-        args: &[Immediate<Provenance>],
+        args: &[ImmTy<'tcx>],
         dest: Option<&MPlaceTy<'tcx>>,
         stack_pop: StackPopCleanup,
     ) -> InterpResult<'tcx> {
         let this = self.eval_context_mut();
-        let param_env = ty::ParamEnv::reveal_all(); // in Miri this is always the param_env we use... and this.param_env is private.
-        let callee_abi = f.ty(*this.tcx, param_env).fn_sig(*this.tcx).abi();
-        if callee_abi != caller_abi {
-            throw_ub_format!(
-                "calling a function with ABI {} using caller ABI {}",
-                callee_abi.name(),
-                caller_abi.name()
-            )
-        }
 
-        // Push frame.
+        // Get MIR.
         let mir = this.load_mir(f.def, None)?;
         let dest = match dest {
             Some(dest) => dest.clone(),
             None => MPlaceTy::fake_alloc_zst(this.layout_of(mir.return_ty())?),
         };
-        this.push_stack_frame(f, mir, &dest, stack_pop)?;
-
-        // Initialize arguments.
-        let mut callee_args = this.frame().body.args_iter();
-        for arg in args {
-            let local = callee_args
-                .next()
-                .ok_or_else(|| err_ub_format!("callee has fewer arguments than expected"))?;
-            // Make the local live, and insert the initial value.
-            this.storage_live(local)?;
-            let callee_arg = this.local_to_place(local)?;
-            this.write_immediate(*arg, &callee_arg)?;
-        }
-        if callee_args.next().is_some() {
-            throw_ub_format!("callee has more arguments than expected");
-        }
-
-        // Initialize remaining locals.
-        this.storage_live_for_always_live_locals()?;
 
-        Ok(())
+        // Construct a function pointer type representing the caller perspective.
+        let sig = this.tcx.mk_fn_sig(
+            args.iter().map(|a| a.layout.ty),
+            dest.layout.ty,
+            /*c_variadic*/ false,
+            Safety::Safe,
+            caller_abi,
+        );
+        let caller_fn_abi = this.fn_abi_of_fn_ptr(ty::Binder::dummy(sig), ty::List::empty())?;
+
+        this.init_stack_frame(
+            f,
+            mir,
+            caller_fn_abi,
+            &args.iter().map(|a| FnArg::Copy(a.clone().into())).collect::<Vec<_>>(),
+            /*with_caller_location*/ false,
+            &dest,
+            stack_pop,
+        )
     }
 
     /// Visits the memory covered by `place`, sensitive to freezing: the 2nd parameter
@@ -1114,12 +1105,12 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
         // Make an attempt to get at the instance of the function this is inlined from.
         let instance: Option<_> = try {
             let scope = frame.current_source_info()?.scope;
-            let inlined_parent = frame.body.source_scopes[scope].inlined_parent_scope?;
-            let source = &frame.body.source_scopes[inlined_parent];
+            let inlined_parent = frame.body().source_scopes[scope].inlined_parent_scope?;
+            let source = &frame.body().source_scopes[inlined_parent];
             source.inlined.expect("inlined_parent_scope points to scope without inline info").0
         };
         // Fall back to the instance of the function itself.
-        let instance = instance.unwrap_or(frame.instance);
+        let instance = instance.unwrap_or(frame.instance());
         // Now check the crate it is in. We could try to be clever here and e.g. check if this is
         // the same crate as `start_fn`, but that would not work for running std tests in Miri, so
         // we'd need some more hacks anyway. So we just check the name of the crate. If someone
@@ -1359,9 +1350,9 @@ impl<'tcx> MiriMachine<'tcx> {
 
     /// This is the source of truth for the `is_user_relevant` flag in our `FrameExtra`.
     pub fn is_user_relevant(&self, frame: &Frame<'tcx, Provenance>) -> bool {
-        let def_id = frame.instance.def_id();
+        let def_id = frame.instance().def_id();
         (def_id.is_local() || self.local_crates.contains(&def_id.krate))
-            && !frame.instance.def.requires_caller_location(self.tcx)
+            && !frame.instance().def.requires_caller_location(self.tcx)
     }
 }
 

src/tools/miri/src/concurrency/thread.rs

@@ -1352,7 +1352,7 @@ impl<'tcx> Machine<'tcx> for MiriMachine<'tcx> {
     ) -> InterpResult<'tcx, Frame<'tcx, Provenance, FrameExtra<'tcx>>> {
         // Start recording our event before doing anything else
         let timing = if let Some(profiler) = ecx.machine.profiler.as_ref() {
-            let fn_name = frame.instance.to_string();
+            let fn_name = frame.instance().to_string();
             let entry = ecx.machine.string_cache.entry(fn_name.clone());
             let name = entry.or_insert_with(|| profiler.alloc_string(&*fn_name));
 
@@ -1443,7 +1443,7 @@ impl<'tcx> Machine<'tcx> for MiriMachine<'tcx> {
         // tracing-tree can autoamtically annotate scope changes, but it gets very confused by our
         // concurrency and what it prints is just plain wrong. So we print our own information
         // instead. (Cc https://github.com/rust-lang/miri/issues/2266)
-        info!("Leaving {}", ecx.frame().instance);
+        info!("Leaving {}", ecx.frame().instance());
         Ok(())
     }
 
@@ -1473,7 +1473,7 @@ impl<'tcx> Machine<'tcx> for MiriMachine<'tcx> {
         // Needs to be done after dropping frame to show up on the right nesting level.
         // (Cc https://github.com/rust-lang/miri/issues/2266)
         if !ecx.active_thread_stack().is_empty() {
-            info!("Continuing in {}", ecx.frame().instance);
+            info!("Continuing in {}", ecx.frame().instance());
         }
         res
     }
@@ -1486,7 +1486,7 @@ impl<'tcx> Machine<'tcx> for MiriMachine<'tcx> {
         let Some(Provenance::Concrete { alloc_id, .. }) = mplace.ptr().provenance else {
             panic!("after_local_allocated should only be called on fresh allocations");
         };
-        let local_decl = &ecx.frame().body.local_decls[local];
+        let local_decl = &ecx.frame().body().local_decls[local];
         let span = local_decl.source_info.span;
         ecx.machine.allocation_spans.borrow_mut().insert(alloc_id, (span, None));
         Ok(())

src/tools/miri/src/eval.rs

@@ -46,8 +46,8 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
         let mut data = Vec::new();
         for frame in this.active_thread_stack().iter().rev() {
             // Match behavior of debuginfo (`FunctionCx::adjusted_span_and_dbg_scope`).
-            let span = hygiene::walk_chain_collapsed(frame.current_span(), frame.body.span);
-            data.push((frame.instance, span.lo()));
+            let span = hygiene::walk_chain_collapsed(frame.current_span(), frame.body().span);
+            data.push((frame.instance(), span.lo()));
         }
 
         let ptrs: Vec<_> = data

src/tools/miri/src/helpers.rs

@@ -25,7 +25,7 @@ pub struct CatchUnwindData<'tcx> {
     /// The `catch_fn` callback to call in case of a panic.
     catch_fn: Pointer,
     /// The `data` argument for that callback.
-    data: Scalar,
+    data: ImmTy<'tcx>,
     /// The return place from the original call to `try`.
     dest: MPlaceTy<'tcx>,
     /// The return block from the original call to `try`.
@@ -48,9 +48,9 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
     fn handle_miri_start_unwind(&mut self, payload: &OpTy<'tcx>) -> InterpResult<'tcx> {
         let this = self.eval_context_mut();
 
-        trace!("miri_start_unwind: {:?}", this.frame().instance);
+        trace!("miri_start_unwind: {:?}", this.frame().instance());
 
-        let payload = this.read_scalar(payload)?;
+        let payload = this.read_immediate(payload)?;
         let thread = this.active_thread_mut();
         thread.panic_payloads.push(payload);
 
@@ -80,7 +80,7 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
         // Get all the arguments.
         let [try_fn, data, catch_fn] = check_arg_count(args)?;
         let try_fn = this.read_pointer(try_fn)?;
-        let data = this.read_scalar(data)?;
+        let data = this.read_immediate(data)?;
         let catch_fn = this.read_pointer(catch_fn)?;
 
         // Now we make a function call, and pass `data` as first and only argument.
@@ -89,7 +89,7 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
         this.call_function(
             f_instance,
             Abi::Rust,
-            &[data.into()],
+            &[data.clone()],
             None,
             // Directly return to caller.
             StackPopCleanup::Goto { ret, unwind: mir::UnwindAction::Continue },
@@ -124,7 +124,7 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
             // and we are unwinding, so we should catch that.
             trace!(
                 "unwinding: found catch_panic frame during unwinding: {:?}",
-                this.frame().instance
+                this.frame().instance()
             );
 
             // We set the return value of `try` to 1, since there was a panic.
@@ -140,7 +140,7 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
             this.call_function(
                 f_instance,
                 Abi::Rust,
-                &[catch_unwind.data.into(), payload.into()],
+                &[catch_unwind.data, payload],
                 None,
                 // Directly return to caller of `try`.
                 StackPopCleanup::Goto {
@@ -169,7 +169,7 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
         this.call_function(
             panic,
             Abi::Rust,
-            &[msg.to_ref(this)],
+            &[this.mplace_to_ref(&msg)?],
             None,
             StackPopCleanup::Goto { ret: None, unwind },
         )
@@ -188,7 +188,7 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
         this.call_function(
             panic,
             Abi::Rust,
-            &[msg.to_ref(this)],
+            &[this.mplace_to_ref(&msg)?],
             None,
             StackPopCleanup::Goto { ret: None, unwind: mir::UnwindAction::Unreachable },
         )
@@ -207,17 +207,17 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
                 // Forward to `panic_bounds_check` lang item.
 
                 // First arg: index.
-                let index = this.read_scalar(&this.eval_operand(index, None)?)?;
+                let index = this.read_immediate(&this.eval_operand(index, None)?)?;
                 // Second arg: len.
-                let len = this.read_scalar(&this.eval_operand(len, None)?)?;
+                let len = this.read_immediate(&this.eval_operand(len, None)?)?;
 
                 // Call the lang item.
                 let panic_bounds_check = this.tcx.lang_items().panic_bounds_check_fn().unwrap();
                 let panic_bounds_check = ty::Instance::mono(this.tcx.tcx, panic_bounds_check);
                 this.call_function(
                     panic_bounds_check,
                     Abi::Rust,
-                    &[index.into(), len.into()],
+                    &[index, len],
                     None,
                     StackPopCleanup::Goto { ret: None, unwind },
                 )?;
@@ -226,9 +226,9 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
                 // Forward to `panic_misaligned_pointer_dereference` lang item.
 
                 // First arg: required.
-                let required = this.read_scalar(&this.eval_operand(required, None)?)?;
+                let required = this.read_immediate(&this.eval_operand(required, None)?)?;
                 // Second arg: found.
-                let found = this.read_scalar(&this.eval_operand(found, None)?)?;
+                let found = this.read_immediate(&this.eval_operand(found, None)?)?;
 
                 // Call the lang item.
                 let panic_misaligned_pointer_dereference =
@@ -238,7 +238,7 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
                 this.call_function(
                     panic_misaligned_pointer_dereference,
                     Abi::Rust,
-                    &[required.into(), found.into()],
+                    &[required, found],
                     None,
                     StackPopCleanup::Goto { ret: None, unwind },
                 )?;

src/tools/miri/src/machine.rs

@@ -315,14 +315,16 @@ trait EvalContextPrivExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
         // FIXME: Technically, the reason should be `DLL_PROCESS_DETACH` when the main thread exits
         // but std treats both the same.
         let reason = this.eval_windows("c", "DLL_THREAD_DETACH");
+        let null_ptr =
+            ImmTy::from_scalar(Scalar::null_ptr(this), this.machine.layouts.const_raw_ptr);
 
         // The signature of this function is `unsafe extern "system" fn(h: c::LPVOID, dwReason: c::DWORD, pv: c::LPVOID)`.
         // FIXME: `h` should be a handle to the current module and what `pv` should be is unknown
         // but both are ignored by std.
         this.call_function(
             thread_callback,
             Abi::System { unwind: false },
-            &[Scalar::null_ptr(this).into(), reason.into(), Scalar::null_ptr(this).into()],
+            &[null_ptr.clone(), ImmTy::from_scalar(reason, this.machine.layouts.u32), null_ptr],
             None,
             StackPopCleanup::Root { cleanup: true },
         )?;
@@ -343,7 +345,7 @@ trait EvalContextPrivExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
             this.call_function(
                 instance,
                 Abi::C { unwind: false },
-                &[data.into()],
+                &[ImmTy::from_scalar(data, this.machine.layouts.mut_raw_ptr)],
                 None,
                 StackPopCleanup::Root { cleanup: true },
             )?;
@@ -380,7 +382,7 @@ trait EvalContextPrivExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
             this.call_function(
                 instance,
                 Abi::C { unwind: false },
-                &[ptr.into()],
+                &[ImmTy::from_scalar(ptr, this.machine.layouts.mut_raw_ptr)],
                 None,
                 StackPopCleanup::Root { cleanup: true },
             )?;

src/tools/miri/src/shims/backtrace.rs

@@ -1,5 +1,4 @@
 use crate::*;
-use rustc_middle::ty::layout::LayoutOf;
 use rustc_target::spec::abi::Abi;
 
 impl<'tcx> EvalContextExt<'tcx> for crate::MiriInterpCx<'tcx> {}
@@ -24,7 +23,7 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
             start_routine,
             Abi::C { unwind: false },
             func_arg,
-            this.layout_of(this.tcx.types.usize)?,
+            this.machine.layouts.mut_raw_ptr,
         )?;
 
         Ok(())

src/tools/miri/src/shims/panic.rs

@@ -1,11 +1,12 @@
 //@ignore-target-windows: No pthreads on Windows
+//~^ERROR: calling a function with more arguments than it expected
 
 //! The thread function must have exactly one argument.
 
 use std::{mem, ptr};
 
 extern "C" fn thread_start() -> *mut libc::c_void {
-    panic!() //~ ERROR: callee has fewer arguments than expected
+    panic!()
 }
 
 fn main() {

src/tools/miri/src/shims/tls.rs

@@ -1,14 +1,10 @@
-error: Undefined Behavior: callee has fewer arguments than expected
-  --> $DIR/libc_pthread_create_too_few_args.rs:LL:CC
-   |
-LL |     panic!()
-   |     ^^^^^^^^ callee has fewer arguments than expected
+error: Undefined Behavior: calling a function with more arguments than it expected
    |
+   = note: calling a function with more arguments than it expected
+   = note: (no span available)
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
    = note: BACKTRACE on thread `unnamed-ID`:
-   = note: inside `thread_start` at RUSTLIB/core/src/panic.rs:LL:CC
-   = note: this error originates in the macro `$crate::panic::panic_2021` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: aborting due to 1 previous error
 

src/tools/miri/src/shims/unix/thread.rs

@@ -1,11 +1,12 @@
 //@ignore-target-windows: No pthreads on Windows
+//~^ERROR: calling a function with fewer arguments than it requires
 
 //! The thread function must have exactly one argument.
 
 use std::{mem, ptr};
 
 extern "C" fn thread_start(_null: *mut libc::c_void, _x: i32) -> *mut libc::c_void {
-    panic!() //~ ERROR: callee has more arguments than expected
+    panic!()
 }
 
 fn main() {

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_create_too_few_args.rs

@@ -1,14 +1,10 @@
-error: Undefined Behavior: callee has more arguments than expected
-  --> $DIR/libc_pthread_create_too_many_args.rs:LL:CC
-   |
-LL |     panic!()
-   |     ^^^^^^^^ callee has more arguments than expected
+error: Undefined Behavior: calling a function with fewer arguments than it requires
    |
+   = note: calling a function with fewer arguments than it requires
+   = note: (no span available)
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
    = note: BACKTRACE on thread `unnamed-ID`:
-   = note: inside `thread_start` at RUSTLIB/core/src/panic.rs:LL:CC
-   = note: this error originates in the macro `$crate::panic::panic_2021` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: aborting due to 1 previous error
 

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_create_too_few_args.stderr

@@ -9,7 +9,7 @@ fn main() {
         // Make sure we check the ABI when Miri itself invokes a function
         // as part of a shim implementation.
         std::intrinsics::catch_unwind(
-            //~^ ERROR: calling a function with ABI C using caller ABI Rust
+            //~^ ERROR: calling a function with calling convention C using calling convention Rust
             std::mem::transmute::<extern "C" fn(*mut u8), _>(try_fn),
             std::ptr::null_mut(),
             |_, _| unreachable!(),

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_create_too_many_args.rs

@@ -1,4 +1,4 @@
-error: Undefined Behavior: calling a function with ABI C using caller ABI Rust
+error: Undefined Behavior: calling a function with calling convention C using calling convention Rust
   --> $DIR/check_callback_abi.rs:LL:CC
    |
 LL | /         std::intrinsics::catch_unwind(
@@ -7,7 +7,7 @@ LL | |             std::mem::transmute::<extern "C" fn(*mut u8), _>(try_fn),
 LL | |             std::ptr::null_mut(),
 LL | |             |_, _| unreachable!(),
 LL | |         );
-   | |_________^ calling a function with ABI C using caller ABI Rust
+   | |_________^ calling a function with calling convention C using calling convention Rust
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_create_too_many_args.stderr

@@ -1,7 +1,7 @@
 #![feature(start)]
 #![no_std]
-//@compile-flags: -Zmiri-track-alloc-id=20 -Zmiri-track-alloc-accesses -Cpanic=abort
-//@normalize-stderr-test: "id 20" -> "id $$ALLOC"
+//@compile-flags: -Zmiri-track-alloc-id=21 -Zmiri-track-alloc-accesses -Cpanic=abort
+//@normalize-stderr-test: "id 21" -> "id $$ALLOC"
 //@only-target-linux: alloc IDs differ between OSes (due to extern static allocations)
 
 extern "Rust" {