rust/src/common.rs

use std::fmt;

use rustc_target::spec::{HasTargetSpec, Target};

use cranelift_module::Module;

use crate::prelude::*;

pub fn mir_var(loc: Local) -> Variable {
    Variable::with_u32(loc.index() as u32)
}

pub fn pointer_ty(tcx: TyCtxt) -> types::Type {
    match tcx.data_layout.pointer_size.bits() {
        16 => types::I16,
        32 => types::I32,
        64 => types::I64,
        bits => bug!("ptr_sized_integer: unknown pointer bit size {}", bits),
    }
}

fn scalar_to_clif_type(tcx: TyCtxt, scalar: &Scalar) -> Type {
    match scalar.value.size(&tcx).bits() {
        8 => types::I8,
        16 => types::I16,
        32 => types::I32,
        64 => types::I64,
        size => bug!("Unsupported scalar size {}", size),
    }
}

pub fn clif_type_from_ty<'a, 'tcx: 'a>(
    tcx: TyCtxt<'a, 'tcx, 'tcx>,
    ty: Ty<'tcx>,
) -> Option<types::Type> {
    Some(match ty.sty {
        ty::Bool => types::I8,
        ty::Uint(size) => match size {
            UintTy::U8 => types::I8,
            UintTy::U16 => types::I16,
            UintTy::U32 => types::I32,
            UintTy::U64 => types::I64,
            UintTy::U128 => unimpl!("u128"),
            UintTy::Usize => pointer_ty(tcx),
        },
        ty::Int(size) => match size {
            IntTy::I8 => types::I8,
            IntTy::I16 => types::I16,
            IntTy::I32 => types::I32,
            IntTy::I64 => types::I64,
            IntTy::I128 => unimpl!("i128"),
            IntTy::Isize => pointer_ty(tcx),
        },
        ty::Char => types::I32,
        ty::Float(size) => match size {
            FloatTy::F32 => types::F32,
            FloatTy::F64 => types::F64,
        },
        ty::FnPtr(_) => pointer_ty(tcx),
        ty::RawPtr(TypeAndMut { ty, mutbl: _ }) | ty::Ref(_, ty, _) => {
            if ty.is_sized(tcx.at(DUMMY_SP), ParamEnv::reveal_all()) {
                pointer_ty(tcx)
            } else {
                return None;
            }
        }
        ty::Param(_) => bug!("{:?}: {:?}", ty, ty.sty),
        _ => return None,
    })
}

pub fn codegen_select(bcx: &mut FunctionBuilder, cond: Value, lhs: Value, rhs: Value) -> Value {
    let lhs_ty = bcx.func.dfg.value_type(lhs);
    let rhs_ty = bcx.func.dfg.value_type(rhs);
    assert_eq!(lhs_ty, rhs_ty);
    if lhs_ty == types::I8 || lhs_ty == types::I16 {
        // FIXME workaround for missing enocding for select.i8
        let lhs = bcx.ins().uextend(types::I32, lhs);
        let rhs = bcx.ins().uextend(types::I32, rhs);
        let res = bcx.ins().select(cond, lhs, rhs);
        bcx.ins().ireduce(lhs_ty, res)
    } else {
        bcx.ins().select(cond, lhs, rhs)
    }
}

fn codegen_field<'a, 'tcx: 'a>(
    fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
    base: Value,
    layout: TyLayout<'tcx>,
    field: mir::Field,
) -> (Value, TyLayout<'tcx>) {
    let field_offset = layout.fields.offset(field.index());
    let field_ty = layout.field(&*fx, field.index());
    if field_offset.bytes() > 0 {
        (
            fx.bcx.ins().iadd_imm(base, field_offset.bytes() as i64),
            field_ty,
        )
    } else {
        (base, field_ty)
    }
}

/// A read-only value
#[derive(Debug, Copy, Clone)]
pub enum CValue<'tcx> {
    ByRef(Value, TyLayout<'tcx>),
    ByVal(Value, TyLayout<'tcx>),
    ByValPair(Value, Value, TyLayout<'tcx>),
}

impl<'tcx> CValue<'tcx> {
    pub fn layout(&self) -> TyLayout<'tcx> {
        match *self {
            CValue::ByRef(_, layout)
            | CValue::ByVal(_, layout)
            | CValue::ByValPair(_, _, layout) => layout,
        }
    }

    pub fn force_stack<'a>(self, fx: &mut FunctionCx<'a, 'tcx, impl Backend>) -> Value
    where
        'tcx: 'a,
    {
        match self {
            CValue::ByRef(value, _layout) => value,
            CValue::ByVal(value, layout) => {
                let stack_slot = fx.bcx.create_stack_slot(StackSlotData {
                    kind: StackSlotKind::ExplicitSlot,
                    size: layout.size.bytes() as u32,
                    offset: None,
                });
                let addr = fx.bcx.ins().stack_addr(fx.pointer_type, stack_slot, 0);
                fx.bcx.ins().store(MemFlags::new(), value, addr, 0);
                addr
            }
            CValue::ByValPair(value, extra, layout) => {
                let stack_slot = fx.bcx.create_stack_slot(StackSlotData {
                    kind: StackSlotKind::ExplicitSlot,
                    size: layout.size.bytes() as u32,
                    offset: None,
                });
                let base = fx.bcx.ins().stack_addr(types::I64, stack_slot, 0);
                let a_addr = codegen_field(fx, base, layout, mir::Field::new(0)).0;
                let b_addr = codegen_field(fx, base, layout, mir::Field::new(1)).0;
                fx.bcx.ins().store(MemFlags::new(), value, a_addr, 0);
                fx.bcx.ins().store(MemFlags::new(), extra, b_addr, 0);
                base
            }
        }
    }

    /// Load a value with layout.abi of scalar
    pub fn load_scalar<'a>(self, fx: &mut FunctionCx<'a, 'tcx, impl Backend>) -> Value
    where
        'tcx: 'a,
    {
        match self {
            CValue::ByRef(addr, layout) => {
                let scalar = match layout.abi {
                    layout::Abi::Scalar(ref scalar) => scalar.clone(),
                    _ => unreachable!(),
                };
                let clif_ty = crate::abi::scalar_to_clif_type(fx.tcx, scalar);
                fx.bcx.ins().load(clif_ty, MemFlags::new(), addr, 0)
            }
            CValue::ByVal(value, _layout) => value,
            CValue::ByValPair(_, _, _layout) => bug!("Please use load_scalar_pair for ByValPair"),
        }
    }

    /// Load a value pair with layout.abi of scalar pair
    pub fn load_scalar_pair<'a>(self, fx: &mut FunctionCx<'a, 'tcx, impl Backend>) -> (Value, Value)
    where
        'tcx: 'a,
    {
        match self {
            CValue::ByRef(addr, layout) => {
                let (a, b) = match &layout.abi {
                    layout::Abi::ScalarPair(a, b) => (a.clone(), b.clone()),
                    _ => unreachable!(),
                };
                let clif_ty1 = crate::abi::scalar_to_clif_type(fx.tcx, a.clone());
                let clif_ty2 = crate::abi::scalar_to_clif_type(fx.tcx, b);
                let val1 = fx.bcx.ins().load(clif_ty1, MemFlags::new(), addr, 0);
                let val2 = fx.bcx.ins().load(
                    clif_ty2,
                    MemFlags::new(),
                    addr,
                    a.value.size(&fx.tcx).bytes() as i32,
                );
                (val1, val2)
            }
            CValue::ByVal(_, _layout) => bug!("Please use load_scalar for ByVal"),
            CValue::ByValPair(val1, val2, _layout) => (val1, val2),
        }
    }

    pub fn value_field<'a>(
        self,
        fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
        field: mir::Field,
    ) -> CValue<'tcx>
    where
        'tcx: 'a,
    {
        let (base, layout) = match self {
            CValue::ByRef(addr, layout) => (addr, layout),
            _ => bug!("place_field for {:?}", self),
        };

        let (field_ptr, field_layout) = codegen_field(fx, base, layout, field);
        CValue::ByRef(field_ptr, field_layout)
    }

    pub fn unsize_value<'a>(self, fx: &mut FunctionCx<'a, 'tcx, impl Backend>, dest: CPlace<'tcx>) {
        crate::unsize::coerce_unsized_into(fx, self, dest);
    }

    pub fn const_val<'a>(
        fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
        ty: Ty<'tcx>,
        const_val: i64,
    ) -> CValue<'tcx>
    where
        'tcx: 'a,
    {
        let clif_ty = fx.clif_type(ty).unwrap();
        let layout = fx.layout_of(ty);
        CValue::ByVal(fx.bcx.ins().iconst(clif_ty, const_val), layout)
    }

    pub fn unchecked_cast_to(self, layout: TyLayout<'tcx>) -> Self {
        match self {
            CValue::ByRef(addr, _) => CValue::ByRef(addr, layout),
            CValue::ByVal(val, _) => CValue::ByVal(val, layout),
            CValue::ByValPair(val, extra, _) => CValue::ByValPair(val, extra, layout),
        }
    }
}

/// A place where you can write a value to or read a value from
#[derive(Debug, Copy, Clone)]
pub enum CPlace<'tcx> {
    Var(Local, TyLayout<'tcx>),
    Addr(Value, Option<Value>, TyLayout<'tcx>),
    Stack(StackSlot, TyLayout<'tcx>),
    NoPlace(TyLayout<'tcx>),
}

impl<'a, 'tcx: 'a> CPlace<'tcx> {
    pub fn layout(&self) -> TyLayout<'tcx> {
        match *self {
            CPlace::Var(_, layout)
            | CPlace::Addr(_, _, layout)
            | CPlace::Stack(_, layout)
            | CPlace::NoPlace(layout) => layout,
        }
    }

    pub fn new_stack_slot(
        fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
        ty: Ty<'tcx>,
    ) -> CPlace<'tcx> {
        let layout = fx.layout_of(ty);
        assert!(!layout.is_unsized());
        if layout.size.bytes() == 0 {
            return CPlace::NoPlace(layout);
        }

        let stack_slot = fx.bcx.create_stack_slot(StackSlotData {
            kind: StackSlotKind::ExplicitSlot,
            size: layout.size.bytes() as u32,
            offset: None,
        });
        CPlace::Stack(stack_slot, layout)
    }

    pub fn to_cvalue(self, fx: &mut FunctionCx<'a, 'tcx, impl Backend>) -> CValue<'tcx> {
        match self {
            CPlace::Var(var, layout) => CValue::ByVal(fx.bcx.use_var(mir_var(var)), layout),
            CPlace::Addr(addr, extra, layout) => {
                assert!(extra.is_none(), "unsized values are not yet supported");
                CValue::ByRef(addr, layout)
            }
            CPlace::Stack(stack_slot, layout) => CValue::ByRef(
                fx.bcx.ins().stack_addr(fx.pointer_type, stack_slot, 0),
                layout,
            ),
            CPlace::NoPlace(layout) => CValue::ByRef(
                fx.bcx
                    .ins()
                    .iconst(fx.pointer_type, fx.pointer_type.bytes() as i64),
                layout,
            ),
        }
    }

    pub fn to_addr(self, fx: &mut FunctionCx<'a, 'tcx, impl Backend>) -> Value {
        match self.to_addr_maybe_unsized(fx) {
            (addr, None) => addr,
            (_, Some(_)) => bug!("Expected sized cplace, found {:?}", self),
        }
    }

    pub fn to_addr_maybe_unsized(
        self,
        fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
    ) -> (Value, Option<Value>) {
        match self {
            CPlace::Addr(addr, extra, _layout) => (addr, extra),
            CPlace::Stack(stack_slot, _layout) => (
                fx.bcx.ins().stack_addr(fx.pointer_type, stack_slot, 0),
                None,
            ),
            CPlace::NoPlace(_) => (fx.bcx.ins().iconst(fx.pointer_type, 45), None),
            CPlace::Var(_, _) => bug!("Expected CPlace::Addr, found CPlace::Var"),
        }
    }

    pub fn write_cvalue(self, fx: &mut FunctionCx<'a, 'tcx, impl Backend>, from: CValue<'tcx>) {
        use rustc::hir::Mutability::*;

        let from_ty = from.layout().ty;
        let to_ty = self.layout().ty;

        fn assert_assignable<'a, 'tcx: 'a>(fx: &FunctionCx<'a, 'tcx, impl Backend>, from_ty: Ty<'tcx>, to_ty: Ty<'tcx>) {
            match (&from_ty.sty, &to_ty.sty) {
                (ty::Ref(_, t, MutImmutable), ty::Ref(_, u, MutImmutable))
                | (ty::Ref(_, t, MutMutable), ty::Ref(_, u, MutImmutable))
                | (ty::Ref(_, t, MutMutable), ty::Ref(_, u, MutMutable)) => {
                    assert_assignable(fx, t, u);
                    // &mut T -> &T is allowed
                    // &'a T -> &'b T is allowed
                }
                (ty::Ref(_, _, MutImmutable), ty::Ref(_, _, MutMutable)) => {
                    panic!("Cant assign value of type {} to place of type {}", from_ty.sty, to_ty.sty)
                }
                (ty::FnPtr(_), ty::FnPtr(_)) => {
                    let from_sig = fx.tcx.normalize_erasing_late_bound_regions(
                        ParamEnv::reveal_all(),
                        &from_ty.fn_sig(fx.tcx),
                    );
                    let to_sig = fx.tcx.normalize_erasing_late_bound_regions(
                        ParamEnv::reveal_all(),
                        &to_ty.fn_sig(fx.tcx),
                    );
                    assert_eq!(
                        from_sig, to_sig,
                        "Can't write fn ptr with incompatible sig {:?} to place with sig {:?}\n\n{:#?}",
                        from_sig, to_sig, fx,
                    );
                    // fn(&T) -> for<'l> fn(&'l T) is allowed
                }
                (ty::Dynamic(from_traits, _), ty::Dynamic(to_traits, _)) => {
                    let from_traits = fx.tcx.normalize_erasing_late_bound_regions(
                        ParamEnv::reveal_all(),
                        from_traits,
                    );
                    let to_traits = fx.tcx.normalize_erasing_late_bound_regions(
                        ParamEnv::reveal_all(),
                        to_traits,
                    );
                    assert_eq!(
                        from_traits, to_traits,
                        "Can't write trait object of incompatible traits {:?} to place with traits {:?}\n\n{:#?}",
                        from_traits, to_traits, fx,
                    );
                    // dyn for<'r> Trait<'r> -> dyn Trait<'_> is allowed
                }
                _ => {
                    assert_eq!(
                        from_ty,
                        to_ty,
                        "Can't write value with incompatible type {:?} to place with type {:?}\n\n{:#?}",
                        from_ty.sty,
                        to_ty.sty,
                        fx,
                    );
                }
            }
        }

        assert_assignable(fx, from_ty, to_ty);

        let (addr, dst_layout) = match self {
            CPlace::Var(var, _) => {
                let data = from.load_scalar(fx);
                fx.bcx.def_var(mir_var(var), data);
                return;
            }
            CPlace::Addr(addr, None, dst_layout) => (addr, dst_layout),
            CPlace::Stack(stack_slot, dst_layout) => (
                fx.bcx.ins().stack_addr(fx.pointer_type, stack_slot, 0),
                dst_layout,
            ),
            CPlace::NoPlace(layout) => {
                assert_eq!(layout.size.bytes(), 0);
                assert_eq!(from.layout().size.bytes(), 0);
                return;
            }
            CPlace::Addr(_, _, _) => bug!("Can't write value to unsized place {:?}", self),
        };

        match from {
            CValue::ByVal(val, _src_layout) => {
                fx.bcx.ins().store(MemFlags::new(), val, addr, 0);
            }
            CValue::ByValPair(val1, val2, _src_layout) => {
                let val1_offset = dst_layout.fields.offset(0).bytes() as i32;
                let val2_offset = dst_layout.fields.offset(1).bytes() as i32;
                fx.bcx.ins().store(MemFlags::new(), val1, addr, val1_offset);
                fx.bcx.ins().store(MemFlags::new(), val2, addr, val2_offset);
            }
            CValue::ByRef(from, src_layout) => {
                let size = dst_layout.size.bytes();
                let src_align = src_layout.align.abi.bytes() as u8;
                let dst_align = dst_layout.align.abi.bytes() as u8;
                fx.bcx.emit_small_memcpy(
                    fx.module.target_config(),
                    addr,
                    from,
                    size,
                    dst_align,
                    src_align,
                );
            }
        }
    }

    pub fn place_field(
        self,
        fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
        field: mir::Field,
    ) -> CPlace<'tcx> {
        let layout = self.layout();
        let (base, extra) = self.to_addr_maybe_unsized(fx);

        let (field_ptr, field_layout) = codegen_field(fx, base, layout, field);
        let extra = if field_layout.is_unsized() {
            assert!(extra.is_some());
            extra
        } else {
            None
        };
        CPlace::Addr(field_ptr, extra, field_layout)
    }

    pub fn place_index(
        self,
        fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
        index: Value,
    ) -> CPlace<'tcx> {
        let (elem_layout, addr) = match self.layout().ty.sty {
            ty::Array(elem_ty, _) => (fx.layout_of(elem_ty), self.to_addr(fx)),
            ty::Slice(elem_ty) => (fx.layout_of(elem_ty), self.to_addr_maybe_unsized(fx).0),
            _ => bug!("place_index({:?})", self.layout().ty),
        };

        let offset = fx
            .bcx
            .ins()
            .imul_imm(index, elem_layout.size.bytes() as i64);

        CPlace::Addr(fx.bcx.ins().iadd(addr, offset), None, elem_layout)
    }

    pub fn place_deref(self, fx: &mut FunctionCx<'a, 'tcx, impl Backend>) -> CPlace<'tcx> {
        let inner_layout = fx.layout_of(self.layout().ty.builtin_deref(true).unwrap().ty);
        if !inner_layout.is_unsized() {
            CPlace::Addr(self.to_cvalue(fx).load_scalar(fx), None, inner_layout)
        } else {
            match self.layout().abi {
                Abi::ScalarPair(ref a, ref b) => {
                    let addr = self.to_addr(fx);
                    let ptr =
                        fx.bcx
                            .ins()
                            .load(scalar_to_clif_type(fx.tcx, a), MemFlags::new(), addr, 0);
                    let extra = fx.bcx.ins().load(
                        scalar_to_clif_type(fx.tcx, b),
                        MemFlags::new(),
                        addr,
                        a.value.size(&fx.tcx).bytes() as u32 as i32,
                    );
                    CPlace::Addr(ptr, Some(extra), inner_layout)
                }
                _ => bug!(
                    "Fat ptr doesn't have abi ScalarPair, but it has {:?}",
                    self.layout().abi
                ),
            }
        }
    }

    pub fn write_place_ref(self, fx: &mut FunctionCx<'a, 'tcx, impl Backend>, dest: CPlace<'tcx>) {
        if !self.layout().is_unsized() {
            let ptr = CValue::ByVal(self.to_addr(fx), dest.layout());
            dest.write_cvalue(fx, ptr);
        } else {
            let (value, extra) = self.to_addr_maybe_unsized(fx);

            match dest.layout().abi {
                Abi::ScalarPair(ref a, _) => {
                    let dest_addr = dest.to_addr(fx);
                    fx.bcx.ins().store(MemFlags::new(), value, dest_addr, 0);
                    fx.bcx.ins().store(
                        MemFlags::new(),
                        extra.expect("unsized type without metadata"),
                        dest_addr,
                        a.value.size(&fx.tcx).bytes() as u32 as i32,
                    );
                }
                _ => bug!(
                    "Non ScalarPair abi {:?} in write_place_ref dest",
                    dest.layout().abi
                ),
            }
        }
    }

    pub fn unchecked_cast_to(self, layout: TyLayout<'tcx>) -> Self {
        assert!(!self.layout().is_unsized());
        match self {
            CPlace::Var(var, _) => CPlace::Var(var, layout),
            CPlace::Addr(addr, extra, _) => CPlace::Addr(addr, extra, layout),
            CPlace::Stack(stack_slot, _) => CPlace::Stack(stack_slot, layout),
            CPlace::NoPlace(_) => {
                assert!(layout.size.bytes() == 0);
                CPlace::NoPlace(layout)
            }
        }
    }

    pub fn downcast_variant(
        self,
        fx: &FunctionCx<'a, 'tcx, impl Backend>,
        variant: VariantIdx,
    ) -> Self {
        let layout = self.layout().for_variant(fx, variant);
        self.unchecked_cast_to(layout)
    }
}

pub fn clif_intcast<'a, 'tcx: 'a>(
    fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
    val: Value,
    to: Type,
    signed: bool,
) -> Value {
    let from = fx.bcx.func.dfg.value_type(val);
    if from == to {
        return val;
    }
    if to.wider_or_equal(from) {
        if signed {
            fx.bcx.ins().sextend(to, val)
        } else {
            fx.bcx.ins().uextend(to, val)
        }
    } else {
        fx.bcx.ins().ireduce(to, val)
    }
}

pub struct FunctionCx<'a, 'tcx: 'a, B: Backend> {
    // FIXME use a reference to `CodegenCx` instead of `tcx`, `module` and `constants` and `caches`
    pub tcx: TyCtxt<'a, 'tcx, 'tcx>,
    pub module: &'a mut Module<B>,
    pub pointer_type: Type, // Cached from module

    pub instance: Instance<'tcx>,
    pub mir: &'tcx Mir<'tcx>,

    pub bcx: FunctionBuilder<'a>,
    pub ebb_map: HashMap<BasicBlock, Ebb>,
    pub local_map: HashMap<Local, CPlace<'tcx>>,

    pub clif_comments: crate::pretty_clif::CommentWriter,
    pub constants: &'a mut crate::constant::ConstantCx,
    pub caches: &'a mut Caches<'tcx>,
    pub source_info_set: indexmap::IndexSet<SourceInfo>,
}

impl<'a, 'tcx: 'a, B: Backend + 'a> fmt::Debug for FunctionCx<'a, 'tcx, B> {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        writeln!(f, "{:?}", self.instance.substs)?;
        writeln!(f, "{:?}", self.local_map)?;

        let mut clif = String::new();
        ::cranelift::codegen::write::decorate_function(
            &mut &self.clif_comments,
            &mut clif,
            &self.bcx.func,
            None,
        )
        .unwrap();
        writeln!(f, "\n{}", clif)
    }
}

impl<'a, 'tcx: 'a, B: Backend> LayoutOf for FunctionCx<'a, 'tcx, B> {
    type Ty = Ty<'tcx>;
    type TyLayout = TyLayout<'tcx>;

    fn layout_of(&self, ty: Ty<'tcx>) -> TyLayout<'tcx> {
        let ty = self.monomorphize(&ty);
        self.tcx.layout_of(ParamEnv::reveal_all().and(&ty)).unwrap()
    }
}

impl<'a, 'tcx, B: Backend + 'a> layout::HasTyCtxt<'tcx> for FunctionCx<'a, 'tcx, B> {
    fn tcx<'b>(&'b self) -> TyCtxt<'b, 'tcx, 'tcx> {
        self.tcx
    }
}

impl<'a, 'tcx, B: Backend + 'a> layout::HasDataLayout for FunctionCx<'a, 'tcx, B> {
    fn data_layout(&self) -> &layout::TargetDataLayout {
        &self.tcx.data_layout
    }
}

impl<'a, 'tcx, B: Backend + 'a> HasTargetSpec for FunctionCx<'a, 'tcx, B> {
    fn target_spec(&self) -> &Target {
        &self.tcx.sess.target.target
    }
}

impl<'a, 'tcx, B: Backend> BackendTypes for FunctionCx<'a, 'tcx, B> {
    type Value = Value;
    type BasicBlock = Ebb;
    type Type = Type;
    type Funclet = !;
    type DIScope = !;
}

impl<'a, 'tcx: 'a, B: Backend + 'a> FunctionCx<'a, 'tcx, B> {
    pub fn monomorphize<T>(&self, value: &T) -> T
    where
        T: TypeFoldable<'tcx>,
    {
        self.tcx.subst_and_normalize_erasing_regions(
            self.instance.substs,
            ty::ParamEnv::reveal_all(),
            value,
        )
    }

    pub fn clif_type(&self, ty: Ty<'tcx>) -> Option<Type> {
        clif_type_from_ty(self.tcx, self.monomorphize(&ty))
    }

    pub fn get_ebb(&self, bb: BasicBlock) -> Ebb {
        *self.ebb_map.get(&bb).unwrap()
    }

    pub fn get_local_place(&mut self, local: Local) -> CPlace<'tcx> {
        *self.local_map.get(&local).unwrap()
    }

    pub fn set_debug_loc(&mut self, source_info: mir::SourceInfo) {
        let (index, _) = self.source_info_set.insert_full(source_info);
        self.bcx.set_srcloc(SourceLoc::new(index as u32));
    }
}