dedup free-form Unsupported errors; add macros for free-form UB and Unsupported cases

Author: RalfJung

src/librustc/mir/interpret/error.rs

@@ -363,7 +363,7 @@ impl fmt::Debug for UndefinedBehaviorInfo {
 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
 pub enum UnsupportedOpInfo<'tcx> {
     /// Handle cases which for which we do not have a fixed variant.
-    Unimplemented(String),
+    Unsupported(String),
 
     // -- Everything below is not classified yet --
     FunctionAbiMismatch(Abi, Abi),
@@ -390,20 +390,14 @@ pub enum UnsupportedOpInfo<'tcx> {
     ReadUndefBytes(Size),
     DeadLocal,
     InvalidBoolOp(mir::BinOp),
-    InlineAsm,
     UnimplementedTraitSelection,
     CalledClosureAsFunction,
     NoMirFor(String),
-    /// This variant is used by machines to signal their own errors that do not
-    /// match an existing variant.
-    MachineError(String),
     DerefFunctionPointer,
     ExecuteMemory,
-    Intrinsic(String),
     InvalidChar(u128),
     OutOfTls,
     TlsOutOfBounds,
-    AbiViolation(String),
     AlignmentCheckFailed {
         required: Align,
         has: Align,
@@ -513,8 +507,6 @@ impl fmt::Debug for UnsupportedOpInfo<'tcx> {
                     initializer"),
             AssumptionNotHeld =>
                 write!(f, "`assume` argument was false"),
-            InlineAsm =>
-                write!(f, "miri does not support inline assembly"),
             ReallocateNonBasePtr =>
                 write!(f, "tried to reallocate with a pointer not to the beginning of an \
                     existing object"),
@@ -537,10 +529,7 @@ impl fmt::Debug for UnsupportedOpInfo<'tcx> {
             HeapAllocNonPowerOfTwoAlignment(_) =>
                 write!(f, "tried to re-, de-, or allocate heap memory with alignment that is \
                     not a power of two"),
-            MachineError(ref msg) |
-            Unimplemented(ref msg) |
-            AbiViolation(ref msg) |
-            Intrinsic(ref msg) =>
+            Unsupported(ref msg) =>
                 write!(f, "{}", msg),
         }
     }

src/librustc/mir/interpret/mod.rs

@@ -50,6 +50,11 @@ macro_rules! throw_unsup {
     ($($tt:tt)*) => { return Err(err_unsup!($($tt)*).into()) };
 }
 
+#[macro_export]
+macro_rules! throw_unsup_format {
+    ($($tt:tt)*) => { throw_unsup!(Unsupported(format!($($tt)*))) };
+}
+
 #[macro_export]
 macro_rules! throw_inval {
     ($($tt:tt)*) => { return Err(err_inval!($($tt)*).into()) };
@@ -60,6 +65,11 @@ macro_rules! throw_ub {
     ($($tt:tt)*) => { return Err(err_ub!($($tt)*).into()) };
 }
 
+#[macro_export]
+macro_rules! throw_ub_format {
+    ($($tt:tt)*) => { throw_ub!(Ub(format!($($tt)*))) };
+}
+
 #[macro_export]
 macro_rules! throw_panic {
     ($($tt:tt)*) => { return Err(err_panic!($($tt)*).into()) };

src/librustc_mir/const_eval.rs

@@ -181,17 +181,17 @@ fn eval_body_using_ecx<'mir, 'tcx>(
     Ok(ret)
 }
 
-impl<'tcx> Into<InterpErrorInfo<'tcx>> for ConstEvalError {
-    fn into(self) -> InterpErrorInfo<'tcx> {
-        err_unsup!(MachineError(self.to_string())).into()
-    }
-}
-
 #[derive(Clone, Debug)]
 enum ConstEvalError {
     NeedsRfc(String),
 }
 
+impl<'tcx> Into<InterpErrorInfo<'tcx>> for ConstEvalError {
+    fn into(self) -> InterpErrorInfo<'tcx> {
+        err_unsup!(Unsupported(self.to_string())).into()
+    }
+}
+
 impl fmt::Display for ConstEvalError {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         use self::ConstEvalError::*;
@@ -341,7 +341,7 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter<'mir,
         debug!("eval_fn_call: {:?}", instance);
         // Only check non-glue functions
         if let ty::InstanceDef::Item(def_id) = instance.def {
-            // Execution might have wandered off into other crates, so we cannot to a stability-
+            // Execution might have wandered off into other crates, so we cannot do a stability-
             // sensitive check here.  But we can at least rule out functions that are not const
             // at all.
             if !ecx.tcx.is_const_fn_raw(def_id) {
@@ -352,7 +352,7 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter<'mir,
                     ecx.goto_block(ret)?; // fully evaluated and done
                     Ok(None)
                 } else {
-                    throw_unsup!(MachineError(format!("calling non-const function `{}`", instance)))
+                    throw_unsup_format!("calling non-const function `{}`", instance)
                 };
             }
         }

src/librustc_mir/interpret/cast.rs

@@ -199,7 +199,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             },
 
             // Casts to bool are not permitted by rustc, no need to handle them here.
-            _ => throw_unsup!(Unimplemented(format!("int to {:?} cast", dest_layout.ty))),
+            _ => bug!("invalid int to {:?} cast", dest_layout.ty),
         }
     }
 

src/librustc_mir/interpret/intrinsics.rs

@@ -98,11 +98,11 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 let bits = self.read_scalar(args[0])?.to_bits(layout_of.size)?;
                 let kind = match layout_of.abi {
                     ty::layout::Abi::Scalar(ref scalar) => scalar.value,
-                    _ => Err(err_unsup!(TypeNotPrimitive(ty)))?,
+                    _ => throw_unsup!(TypeNotPrimitive(ty)),
                 };
                 let out_val = if intrinsic_name.ends_with("_nonzero") {
                     if bits == 0 {
-                        throw_unsup!(Intrinsic(format!("{} called on 0", intrinsic_name)))
+                        throw_ub_format!("`{}` called on 0", intrinsic_name);
                     }
                     numeric_intrinsic(intrinsic_name.trim_end_matches("_nonzero"), bits, kind)?
                 } else {
@@ -187,10 +187,8 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 let (val, overflowed) = self.binary_op(bin_op, l, r)?;
                 if overflowed {
                     let layout = self.layout_of(substs.type_at(0))?;
-                    let r_val =  r.to_scalar()?.to_bits(layout.size)?;
-                    throw_unsup!(
-                        Intrinsic(format!("Overflowing shift by {} in {}", r_val, intrinsic_name))
-                    )
+                    let r_val = r.to_scalar()?.to_bits(layout.size)?;
+                    throw_ub_format!("Overflowing shift by {} in `{}`", r_val, intrinsic_name);
                 }
                 self.write_scalar(val, dest)?;
             }

src/librustc_mir/interpret/memory.rs

@@ -66,9 +66,9 @@ impl<'tcx, Other> FnVal<'tcx, Other> {
         match self {
             FnVal::Instance(instance) =>
                 Ok(instance),
-            FnVal::Other(_) => throw_unsup!(MachineError(format!(
-                "Expected instance function pointer, got 'other' pointer"
-            ))),
+            FnVal::Other(_) => throw_unsup_format!(
+                "'foreign' function pointers are not supported in this context"
+            ),
         }
     }
 }
@@ -834,9 +834,9 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
                     if (src.offset <= dest.offset && src.offset + size > dest.offset) ||
                         (dest.offset <= src.offset && dest.offset + size > src.offset)
                     {
-                        throw_unsup!(Intrinsic(
-                            "copy_nonoverlapping called on overlapping ranges".to_string(),
-                        ))
+                        throw_ub_format!(
+                            "copy_nonoverlapping called on overlapping ranges"
+                        )
                     }
                 }
 

src/librustc_mir/interpret/operator.rs

@@ -147,15 +147,12 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
 
         // For the remaining ops, the types must be the same on both sides
         if left_layout.ty != right_layout.ty {
-            let msg = format!(
-                "unimplemented asymmetric binary op {:?}: {:?} ({:?}), {:?} ({:?})",
+            bug!(
+                "invalid asymmetric binary op {:?}: {:?} ({:?}), {:?} ({:?})",
                 bin_op,
-                l,
-                left_layout.ty,
-                r,
-                right_layout.ty
-            );
-            throw_unsup!(Unimplemented(msg))
+                l, left_layout.ty,
+                r, right_layout.ty,
+            )
         }
 
         // Operations that need special treatment for signed integers
@@ -243,14 +240,13 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             }
 
             _ => {
-                let msg = format!(
-                    "unimplemented binary op {:?}: {:?}, {:?} (both {:?})",
+                bug!(
+                    "invalid binary op {:?}: {:?}, {:?} (both {:?})",
                     bin_op,
                     l,
                     r,
                     right_layout.ty,
-                );
-                throw_unsup!(Unimplemented(msg))
+                )
             }
         };
 

src/librustc_mir/interpret/step.rs

@@ -121,7 +121,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             // size of MIR constantly.
             Nop => {}
 
-            InlineAsm { .. } => throw_unsup!(InlineAsm),
+            InlineAsm { .. } => throw_unsup_format!("inline assembly is not supported"),
         }
 
         self.stack[frame_idx].stmt += 1;

src/librustc_mir/interpret/terminator.rs

@@ -88,8 +88,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                         (FnVal::Instance(self.resolve(def_id, substs)?), sig.abi())
                     },
                     _ => {
-                        let msg = format!("can't handle callee of type {:?}", func.layout.ty);
-                        throw_unsup!(Unimplemented(msg))
+                        bug!("invalid callee of type {:?}", func.layout.ty)
                     }
                 };
                 let args = self.eval_operands(args)?;