implement proper panicking for other MIR assertions

Requires generalizing the call_function helper to arbitrary Immediate arguments

Author: RalfJung

src/eval.rs

@@ -103,7 +103,7 @@ pub fn create_ecx<'mir, 'tcx: 'mir>(
         let argvs_place = ecx.allocate(argvs_layout, MiriMemoryKind::Env.into());
         for (idx, arg) in argvs.into_iter().enumerate() {
             let place = ecx.mplace_field(argvs_place, idx as u64)?;
-            ecx.write_scalar(Scalar::Ptr(arg), place.into())?;
+            ecx.write_scalar(arg, place.into())?;
         }
         ecx.memory
             .mark_immutable(argvs_place.ptr.assert_ptr().alloc_id)?;
@@ -149,7 +149,7 @@ pub fn create_ecx<'mir, 'tcx: 'mir>(
     // Call start function.
     ecx.call_function(
         start_instance,
-        &[main_ptr.into(), argc, argv],
+        &[main_ptr.into(), argc.into(), argv.into()],
         Some(ret_place.into()),
         StackPopCleanup::None { cleanup: true },
     )?;

src/helpers.rs

@@ -124,7 +124,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
     fn call_function(
         &mut self,
         f: ty::Instance<'tcx>,
-        args: &[Scalar<Tag>],
+        args: &[Immediate<Tag>],
         dest: Option<PlaceTy<'tcx, Tag>>,
         stack_pop: StackPopCleanup,
     ) -> InterpResult<'tcx> {
@@ -146,7 +146,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             let callee_arg = this.local_place(
                 callee_args.next().expect("callee has fewer arguments than expected")
             )?;
-            this.write_scalar(*arg, callee_arg)?;
+            this.write_immediate(*arg, callee_arg)?;
         }
         callee_args.next().expect_none("callee has more arguments than expected");
 

src/machine.rs

@@ -253,7 +253,7 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for Evaluator<'tcx> {
         let malloc = ty::Instance::mono(ecx.tcx.tcx, malloc);
         ecx.call_function(
             malloc,
-            &[size, align],
+            &[size.into(), align.into()],
             Some(dest),
             // Don't do anything when we are done. The `statement()` function will increment
             // the old stack frame's stmt counter to the next statement, which means that when

src/shims/env.rs

@@ -57,7 +57,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         Ok(match this.machine.env_vars.map.get(name) {
             // The offset is used to strip the "{name}=" part of the string.
             Some(var_ptr) => {
-                Scalar::Ptr(var_ptr.offset(Size::from_bytes(name.len() as u64 + 1), this)?)
+                Scalar::from(var_ptr.offset(Size::from_bytes(name.len() as u64 + 1), this)?)
             }
             None => Scalar::ptr_null(&*this.tcx),
         })

src/shims/foreign_items.rs

@@ -205,7 +205,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                         Align::from_bytes(align).unwrap(),
                         MiriMemoryKind::C.into(),
                     );
-                    this.write_scalar(Scalar::Ptr(ptr), ret.into())?;
+                    this.write_scalar(ptr, ret.into())?;
                 }
                 this.write_null(dest)?;
             }
@@ -234,7 +234,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                     Align::from_bytes(align).unwrap(),
                     MiriMemoryKind::Rust.into(),
                 );
-                this.write_scalar(Scalar::Ptr(ptr), dest)?;
+                this.write_scalar(ptr, dest)?;
             }
             "__rust_alloc_zeroed" => {
                 let size = this.read_scalar(args[0])?.to_machine_usize(this)?;
@@ -254,7 +254,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                 this.memory
                     .write_bytes(ptr.into(), iter::repeat(0u8).take(size as usize))
                     .unwrap();
-                this.write_scalar(Scalar::Ptr(ptr), dest)?;
+                this.write_scalar(ptr, dest)?;
             }
             "__rust_dealloc" => {
                 let ptr = this.read_scalar(args[0])?.not_undef()?;
@@ -295,7 +295,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                     align,
                     MiriMemoryKind::Rust.into(),
                 )?;
-                this.write_scalar(Scalar::Ptr(new_ptr), dest)?;
+                this.write_scalar(new_ptr, dest)?;
             }
 
             "syscall" => {

src/shims/panic.rs

@@ -86,7 +86,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             MPlaceTy::dangling(this.layout_of(tcx.mk_unit())?, this).into();
         this.call_function(
             f_instance,
-            &[f_arg],
+            &[f_arg.into()],
             Some(ret_place),
             // Directly return to caller.
             StackPopCleanup::Goto { ret: Some(ret), unwind: None },
@@ -163,6 +163,8 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
 
         match msg {
             BoundsCheck { ref index, ref len } => {
+                // Forward to `panic_bounds_check` lang item.
+
                 // First arg: Caller location.
                 let location = this.alloc_caller_location_for_span(span)?;
                 // Second arg: index.
@@ -175,12 +177,31 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                 let panic_bounds_check = ty::Instance::mono(this.tcx.tcx, panic_bounds_check);
                 this.call_function(
                     panic_bounds_check,
-                    &[location.ptr, index.not_undef()?, len.not_undef()?],
+                    &[location.ptr.into(), index.into(), len.into()],
+                    None,
+                    StackPopCleanup::Goto { ret: None, unwind },
+                )?;
+            }
+            _ => {
+                // Forward everything else to `panic` lang item.
+
+                // First arg: Message.
+                let msg = msg.description();
+                let msg = this.allocate_str(msg, MiriMemoryKind::Static.into());
+
+                // Second arg: Caller location.
+                let location = this.alloc_caller_location_for_span(span)?;
+
+                // Call the lang item.
+                let panic = this.tcx.lang_items().panic_fn().unwrap();
+                let panic = ty::Instance::mono(this.tcx.tcx, panic);
+                this.call_function(
+                    panic,
+                    &[msg.to_ref(), location.ptr.into()],
                     None,
                     StackPopCleanup::Goto { ret: None, unwind },
                 )?;
             }
-            _ => unimplemented!()
         }
         Ok(())
     }

src/shims/tls.rs

@@ -150,7 +150,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             let ret_place = MPlaceTy::dangling(this.layout_of(this.tcx.mk_unit())?, this).into();
             this.call_function(
                 instance,
-                &[ptr],
+                &[ptr.into()],
                 Some(ret_place),
                 StackPopCleanup::None { cleanup: true },
             )?;