diff options
Diffstat (limited to 'compiler/rustc_codegen_cranelift/src/value_and_place.rs')
| -rw-r--r-- | compiler/rustc_codegen_cranelift/src/value_and_place.rs | 777 |
1 files changed, 777 insertions, 0 deletions
diff --git a/compiler/rustc_codegen_cranelift/src/value_and_place.rs b/compiler/rustc_codegen_cranelift/src/value_and_place.rs new file mode 100644 index 00000000000..5d513cb3ea0 --- /dev/null +++ b/compiler/rustc_codegen_cranelift/src/value_and_place.rs @@ -0,0 +1,777 @@ +//! Definition of [`CValue`] and [`CPlace`] + +use crate::prelude::*; + +use cranelift_codegen::entity::EntityRef; +use cranelift_codegen::ir::immediates::Offset32; + +fn codegen_field<'tcx>( + fx: &mut FunctionCx<'_, 'tcx, impl Module>, + base: Pointer, + extra: Option<Value>, + layout: TyAndLayout<'tcx>, + field: mir::Field, +) -> (Pointer, TyAndLayout<'tcx>) { + let field_offset = layout.fields.offset(field.index()); + let field_layout = layout.field(&*fx, field.index()); + + let simple = |fx: &mut FunctionCx<'_, '_, _>| { + ( + base.offset_i64(fx, i64::try_from(field_offset.bytes()).unwrap()), + field_layout, + ) + }; + + if let Some(extra) = extra { + if !field_layout.is_unsized() { + return simple(fx); + } + match field_layout.ty.kind() { + ty::Slice(..) | ty::Str | ty::Foreign(..) => return simple(fx), + ty::Adt(def, _) if def.repr.packed() => { + assert_eq!(layout.align.abi.bytes(), 1); + return simple(fx); + } + _ => { + // We have to align the offset for DST's + let unaligned_offset = field_offset.bytes(); + let (_, unsized_align) = + crate::unsize::size_and_align_of_dst(fx, field_layout, extra); + + let one = fx.bcx.ins().iconst(pointer_ty(fx.tcx), 1); + let align_sub_1 = fx.bcx.ins().isub(unsized_align, one); + let and_lhs = fx.bcx.ins().iadd_imm(align_sub_1, unaligned_offset as i64); + let zero = fx.bcx.ins().iconst(pointer_ty(fx.tcx), 0); + let and_rhs = fx.bcx.ins().isub(zero, unsized_align); + let offset = fx.bcx.ins().band(and_lhs, and_rhs); + + (base.offset_value(fx, offset), field_layout) + } + } + } else { + simple(fx) + } +} + +fn scalar_pair_calculate_b_offset( + tcx: TyCtxt<'_>, + a_scalar: &Scalar, + b_scalar: &Scalar, +) -> Offset32 { + let b_offset = a_scalar + .value + .size(&tcx) + .align_to(b_scalar.value.align(&tcx).abi); + Offset32::new(b_offset.bytes().try_into().unwrap()) +} + +/// A read-only value +#[derive(Debug, Copy, Clone)] +pub(crate) struct CValue<'tcx>(CValueInner, TyAndLayout<'tcx>); + +#[derive(Debug, Copy, Clone)] +enum CValueInner { + ByRef(Pointer, Option<Value>), + ByVal(Value), + ByValPair(Value, Value), +} + +impl<'tcx> CValue<'tcx> { + pub(crate) fn by_ref(ptr: Pointer, layout: TyAndLayout<'tcx>) -> CValue<'tcx> { + CValue(CValueInner::ByRef(ptr, None), layout) + } + + pub(crate) fn by_ref_unsized( + ptr: Pointer, + meta: Value, + layout: TyAndLayout<'tcx>, + ) -> CValue<'tcx> { + CValue(CValueInner::ByRef(ptr, Some(meta)), layout) + } + + pub(crate) fn by_val(value: Value, layout: TyAndLayout<'tcx>) -> CValue<'tcx> { + CValue(CValueInner::ByVal(value), layout) + } + + pub(crate) fn by_val_pair( + value: Value, + extra: Value, + layout: TyAndLayout<'tcx>, + ) -> CValue<'tcx> { + CValue(CValueInner::ByValPair(value, extra), layout) + } + + pub(crate) fn layout(&self) -> TyAndLayout<'tcx> { + self.1 + } + + // FIXME remove + pub(crate) fn force_stack( + self, + fx: &mut FunctionCx<'_, 'tcx, impl Module>, + ) -> (Pointer, Option<Value>) { + let layout = self.1; + match self.0 { + CValueInner::ByRef(ptr, meta) => (ptr, meta), + CValueInner::ByVal(_) | CValueInner::ByValPair(_, _) => { + let cplace = CPlace::new_stack_slot(fx, layout); + cplace.write_cvalue(fx, self); + (cplace.to_ptr(), None) + } + } + } + + pub(crate) fn try_to_ptr(self) -> Option<(Pointer, Option<Value>)> { + match self.0 { + CValueInner::ByRef(ptr, meta) => Some((ptr, meta)), + CValueInner::ByVal(_) | CValueInner::ByValPair(_, _) => None, + } + } + + /// Load a value with layout.abi of scalar + pub(crate) fn load_scalar(self, fx: &mut FunctionCx<'_, 'tcx, impl Module>) -> Value { + let layout = self.1; + match self.0 { + CValueInner::ByRef(ptr, None) => { + let clif_ty = match layout.abi { + Abi::Scalar(ref scalar) => scalar_to_clif_type(fx.tcx, scalar.clone()), + Abi::Vector { ref element, count } => { + scalar_to_clif_type(fx.tcx, element.clone()) + .by(u16::try_from(count).unwrap()) + .unwrap() + } + _ => unreachable!("{:?}", layout.ty), + }; + let mut flags = MemFlags::new(); + flags.set_notrap(); + ptr.load(fx, clif_ty, flags) + } + CValueInner::ByVal(value) => value, + CValueInner::ByRef(_, Some(_)) => bug!("load_scalar for unsized value not allowed"), + CValueInner::ByValPair(_, _) => bug!("Please use load_scalar_pair for ByValPair"), + } + } + + /// Load a value pair with layout.abi of scalar pair + pub(crate) fn load_scalar_pair( + self, + fx: &mut FunctionCx<'_, 'tcx, impl Module>, + ) -> (Value, Value) { + let layout = self.1; + match self.0 { + CValueInner::ByRef(ptr, None) => { + let (a_scalar, b_scalar) = match &layout.abi { + Abi::ScalarPair(a, b) => (a, b), + _ => unreachable!("load_scalar_pair({:?})", self), + }; + let b_offset = scalar_pair_calculate_b_offset(fx.tcx, a_scalar, b_scalar); + let clif_ty1 = scalar_to_clif_type(fx.tcx, a_scalar.clone()); + let clif_ty2 = scalar_to_clif_type(fx.tcx, b_scalar.clone()); + let mut flags = MemFlags::new(); + flags.set_notrap(); + let val1 = ptr.load(fx, clif_ty1, flags); + let val2 = ptr.offset(fx, b_offset).load(fx, clif_ty2, flags); + (val1, val2) + } + CValueInner::ByRef(_, Some(_)) => { + bug!("load_scalar_pair for unsized value not allowed") + } + CValueInner::ByVal(_) => bug!("Please use load_scalar for ByVal"), + CValueInner::ByValPair(val1, val2) => (val1, val2), + } + } + + pub(crate) fn value_field( + self, + fx: &mut FunctionCx<'_, 'tcx, impl Module>, + field: mir::Field, + ) -> CValue<'tcx> { + let layout = self.1; + match self.0 { + CValueInner::ByVal(val) => match layout.abi { + Abi::Vector { element: _, count } => { + let count = u8::try_from(count).expect("SIMD type with more than 255 lanes???"); + let field = u8::try_from(field.index()).unwrap(); + assert!(field < count); + let lane = fx.bcx.ins().extractlane(val, field); + let field_layout = layout.field(&*fx, usize::from(field)); + CValue::by_val(lane, field_layout) + } + _ => unreachable!("value_field for ByVal with abi {:?}", layout.abi), + }, + CValueInner::ByValPair(val1, val2) => match layout.abi { + Abi::ScalarPair(_, _) => { + let val = match field.as_u32() { + 0 => val1, + 1 => val2, + _ => bug!("field should be 0 or 1"), + }; + let field_layout = layout.field(&*fx, usize::from(field)); + CValue::by_val(val, field_layout) + } + _ => unreachable!("value_field for ByValPair with abi {:?}", layout.abi), + }, + CValueInner::ByRef(ptr, None) => { + let (field_ptr, field_layout) = codegen_field(fx, ptr, None, layout, field); + CValue::by_ref(field_ptr, field_layout) + } + CValueInner::ByRef(_, Some(_)) => todo!(), + } + } + + pub(crate) fn unsize_value( + self, + fx: &mut FunctionCx<'_, 'tcx, impl Module>, + dest: CPlace<'tcx>, + ) { + crate::unsize::coerce_unsized_into(fx, self, dest); + } + + /// If `ty` is signed, `const_val` must already be sign extended. + pub(crate) fn const_val( + fx: &mut FunctionCx<'_, 'tcx, impl Module>, + layout: TyAndLayout<'tcx>, + const_val: u128, + ) -> CValue<'tcx> { + use cranelift_codegen::ir::immediates::{Ieee32, Ieee64}; + + let clif_ty = fx.clif_type(layout.ty).unwrap(); + + match layout.ty.kind() { + ty::Bool => { + assert!( + const_val == 0 || const_val == 1, + "Invalid bool 0x{:032X}", + const_val + ); + } + _ => {} + } + + let val = match layout.ty.kind() { + ty::Uint(UintTy::U128) | ty::Int(IntTy::I128) => { + let lsb = fx.bcx.ins().iconst(types::I64, const_val as u64 as i64); + let msb = fx + .bcx + .ins() + .iconst(types::I64, (const_val >> 64) as u64 as i64); + fx.bcx.ins().iconcat(lsb, msb) + } + ty::Bool | ty::Char | ty::Uint(_) | ty::Int(_) | ty::Ref(..) + | ty::RawPtr(..) => { + fx + .bcx + .ins() + .iconst(clif_ty, u64::try_from(const_val).expect("uint") as i64) + } + ty::Float(FloatTy::F32) => { + fx.bcx.ins().f32const(Ieee32::with_bits(u32::try_from(const_val).unwrap())) + } + ty::Float(FloatTy::F64) => { + fx.bcx.ins().f64const(Ieee64::with_bits(u64::try_from(const_val).unwrap())) + } + _ => panic!( + "CValue::const_val for non bool/char/float/integer/pointer type {:?} is not allowed", + layout.ty + ), + }; + + CValue::by_val(val, layout) + } + + pub(crate) fn cast_pointer_to(self, layout: TyAndLayout<'tcx>) -> Self { + assert!(matches!( + self.layout().ty.kind(), + ty::Ref(..) | ty::RawPtr(..) | ty::FnPtr(..) + )); + assert!(matches!( + layout.ty.kind(), + ty::Ref(..) | ty::RawPtr(..) | ty::FnPtr(..) + )); + assert_eq!(self.layout().abi, layout.abi); + CValue(self.0, layout) + } +} + +/// A place where you can write a value to or read a value from +#[derive(Debug, Copy, Clone)] +pub(crate) struct CPlace<'tcx> { + inner: CPlaceInner, + layout: TyAndLayout<'tcx>, +} + +#[derive(Debug, Copy, Clone)] +pub(crate) enum CPlaceInner { + Var(Local, Variable), + VarPair(Local, Variable, Variable), + VarLane(Local, Variable, u8), + Addr(Pointer, Option<Value>), +} + +impl<'tcx> CPlace<'tcx> { + pub(crate) fn layout(&self) -> TyAndLayout<'tcx> { + self.layout + } + + pub(crate) fn inner(&self) -> &CPlaceInner { + &self.inner + } + + pub(crate) fn no_place(layout: TyAndLayout<'tcx>) -> CPlace<'tcx> { + CPlace { + inner: CPlaceInner::Addr(Pointer::dangling(layout.align.pref), None), + layout, + } + } + + pub(crate) fn new_stack_slot( + fx: &mut FunctionCx<'_, 'tcx, impl Module>, + layout: TyAndLayout<'tcx>, + ) -> CPlace<'tcx> { + assert!(!layout.is_unsized()); + if layout.size.bytes() == 0 { + return CPlace::no_place(layout); + } + + let stack_slot = fx.bcx.create_stack_slot(StackSlotData { + kind: StackSlotKind::ExplicitSlot, + size: layout.size.bytes() as u32, + offset: None, + }); + CPlace { + inner: CPlaceInner::Addr(Pointer::stack_slot(stack_slot), None), + layout, + } + } + + pub(crate) fn new_var( + fx: &mut FunctionCx<'_, 'tcx, impl Module>, + local: Local, + layout: TyAndLayout<'tcx>, + ) -> CPlace<'tcx> { + let var = Variable::with_u32(fx.next_ssa_var); + fx.next_ssa_var += 1; + fx.bcx.declare_var(var, fx.clif_type(layout.ty).unwrap()); + CPlace { + inner: CPlaceInner::Var(local, var), + layout, + } + } + + pub(crate) fn new_var_pair( + fx: &mut FunctionCx<'_, 'tcx, impl Module>, + local: Local, + layout: TyAndLayout<'tcx>, + ) -> CPlace<'tcx> { + let var1 = Variable::with_u32(fx.next_ssa_var); + fx.next_ssa_var += 1; + let var2 = Variable::with_u32(fx.next_ssa_var); + fx.next_ssa_var += 1; + + let (ty1, ty2) = fx.clif_pair_type(layout.ty).unwrap(); + fx.bcx.declare_var(var1, ty1); + fx.bcx.declare_var(var2, ty2); + CPlace { + inner: CPlaceInner::VarPair(local, var1, var2), + layout, + } + } + + pub(crate) fn for_ptr(ptr: Pointer, layout: TyAndLayout<'tcx>) -> CPlace<'tcx> { + CPlace { + inner: CPlaceInner::Addr(ptr, None), + layout, + } + } + + pub(crate) fn for_ptr_with_extra( + ptr: Pointer, + extra: Value, + layout: TyAndLayout<'tcx>, + ) -> CPlace<'tcx> { + CPlace { + inner: CPlaceInner::Addr(ptr, Some(extra)), + layout, + } + } + + pub(crate) fn to_cvalue(self, fx: &mut FunctionCx<'_, 'tcx, impl Module>) -> CValue<'tcx> { + let layout = self.layout(); + match self.inner { + CPlaceInner::Var(_local, var) => { + let val = fx.bcx.use_var(var); + fx.bcx + .set_val_label(val, cranelift_codegen::ir::ValueLabel::new(var.index())); + CValue::by_val(val, layout) + } + CPlaceInner::VarPair(_local, var1, var2) => { + let val1 = fx.bcx.use_var(var1); + fx.bcx + .set_val_label(val1, cranelift_codegen::ir::ValueLabel::new(var1.index())); + let val2 = fx.bcx.use_var(var2); + fx.bcx + .set_val_label(val2, cranelift_codegen::ir::ValueLabel::new(var2.index())); + CValue::by_val_pair(val1, val2, layout) + } + CPlaceInner::VarLane(_local, var, lane) => { + let val = fx.bcx.use_var(var); + fx.bcx + .set_val_label(val, cranelift_codegen::ir::ValueLabel::new(var.index())); + let val = fx.bcx.ins().extractlane(val, lane); + CValue::by_val(val, layout) + } + CPlaceInner::Addr(ptr, extra) => { + if let Some(extra) = extra { + CValue::by_ref_unsized(ptr, extra, layout) + } else { + CValue::by_ref(ptr, layout) + } + } + } + } + + pub(crate) fn to_ptr(self) -> Pointer { + match self.to_ptr_maybe_unsized() { + (ptr, None) => ptr, + (_, Some(_)) => bug!("Expected sized cplace, found {:?}", self), + } + } + + pub(crate) fn to_ptr_maybe_unsized(self) -> (Pointer, Option<Value>) { + match self.inner { + CPlaceInner::Addr(ptr, extra) => (ptr, extra), + CPlaceInner::Var(_, _) + | CPlaceInner::VarPair(_, _, _) + | CPlaceInner::VarLane(_, _, _) => bug!("Expected CPlace::Addr, found {:?}", self), + } + } + + pub(crate) fn write_cvalue( + self, + fx: &mut FunctionCx<'_, 'tcx, impl Module>, + from: CValue<'tcx>, + ) { + fn assert_assignable<'tcx>( + fx: &FunctionCx<'_, 'tcx, impl Module>, + from_ty: Ty<'tcx>, + to_ty: Ty<'tcx>, + ) { + match (&from_ty.kind(), &to_ty.kind()) { + (ty::Ref(_, a, _), ty::Ref(_, b, _)) + | ( + ty::RawPtr(TypeAndMut { ty: a, mutbl: _ }), + ty::RawPtr(TypeAndMut { ty: b, mutbl: _ }), + ) => { + assert_assignable(fx, a, b); + } + (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, + to_ty, + fx, + ); + } + } + } + + assert_assignable(fx, from.layout().ty, self.layout().ty); + + self.write_cvalue_maybe_transmute(fx, from, "write_cvalue"); + } + + pub(crate) fn write_cvalue_transmute( + self, + fx: &mut FunctionCx<'_, 'tcx, impl Module>, + from: CValue<'tcx>, + ) { + self.write_cvalue_maybe_transmute(fx, from, "write_cvalue_transmute"); + } + + fn write_cvalue_maybe_transmute( + self, + fx: &mut FunctionCx<'_, 'tcx, impl Module>, + from: CValue<'tcx>, + #[cfg_attr(not(debug_assertions), allow(unused_variables))] method: &'static str, + ) { + fn transmute_value<'tcx>( + fx: &mut FunctionCx<'_, 'tcx, impl Module>, + var: Variable, + data: Value, + dst_ty: Type, + ) { + let src_ty = fx.bcx.func.dfg.value_type(data); + let data = match (src_ty, dst_ty) { + (_, _) if src_ty == dst_ty => data, + + // This is a `write_cvalue_transmute`. + (types::I32, types::F32) + | (types::F32, types::I32) + | (types::I64, types::F64) + | (types::F64, types::I64) => fx.bcx.ins().bitcast(dst_ty, data), + _ if src_ty.is_vector() && dst_ty.is_vector() => { + fx.bcx.ins().raw_bitcast(dst_ty, data) + } + _ => unreachable!("write_cvalue_transmute: {:?} -> {:?}", src_ty, dst_ty), + }; + fx.bcx + .set_val_label(data, cranelift_codegen::ir::ValueLabel::new(var.index())); + fx.bcx.def_var(var, data); + } + + assert_eq!(self.layout().size, from.layout().size); + + #[cfg(debug_assertions)] + { + use cranelift_codegen::cursor::{Cursor, CursorPosition}; + let cur_block = match fx.bcx.cursor().position() { + CursorPosition::After(block) => block, + _ => unreachable!(), + }; + fx.add_comment( + fx.bcx.func.layout.last_inst(cur_block).unwrap(), + format!( + "{}: {:?}: {:?} <- {:?}: {:?}", + method, + self.inner(), + self.layout().ty, + from.0, + from.layout().ty + ), + ); + } + + let dst_layout = self.layout(); + let to_ptr = match self.inner { + CPlaceInner::Var(_local, var) => { + let data = CValue(from.0, dst_layout).load_scalar(fx); + let dst_ty = fx.clif_type(self.layout().ty).unwrap(); + transmute_value(fx, var, data, dst_ty); + return; + } + CPlaceInner::VarPair(_local, var1, var2) => { + let (data1, data2) = CValue(from.0, dst_layout).load_scalar_pair(fx); + let (dst_ty1, dst_ty2) = fx.clif_pair_type(self.layout().ty).unwrap(); + transmute_value(fx, var1, data1, dst_ty1); + transmute_value(fx, var2, data2, dst_ty2); + return; + } + CPlaceInner::VarLane(_local, var, lane) => { + let data = from.load_scalar(fx); + + // First get the old vector + let vector = fx.bcx.use_var(var); + fx.bcx + .set_val_label(vector, cranelift_codegen::ir::ValueLabel::new(var.index())); + + // Next insert the written lane into the vector + let vector = fx.bcx.ins().insertlane(vector, data, lane); + + // Finally write the new vector + fx.bcx + .set_val_label(vector, cranelift_codegen::ir::ValueLabel::new(var.index())); + fx.bcx.def_var(var, vector); + + return; + } + CPlaceInner::Addr(ptr, None) => { + if dst_layout.size == Size::ZERO || dst_layout.abi == Abi::Uninhabited { + return; + } + ptr + } + CPlaceInner::Addr(_, Some(_)) => bug!("Can't write value to unsized place {:?}", self), + }; + + let mut flags = MemFlags::new(); + flags.set_notrap(); + match from.layout().abi { + // FIXME make Abi::Vector work too + Abi::Scalar(_) => { + let val = from.load_scalar(fx); + to_ptr.store(fx, val, flags); + return; + } + Abi::ScalarPair(ref a_scalar, ref b_scalar) => { + let (value, extra) = from.load_scalar_pair(fx); + let b_offset = scalar_pair_calculate_b_offset(fx.tcx, a_scalar, b_scalar); + to_ptr.store(fx, value, flags); + to_ptr.offset(fx, b_offset).store(fx, extra, flags); + return; + } + _ => {} + } + + match from.0 { + CValueInner::ByVal(val) => { + to_ptr.store(fx, val, flags); + } + CValueInner::ByValPair(_, _) => { + bug!( + "Non ScalarPair abi {:?} for ByValPair CValue", + dst_layout.abi + ); + } + CValueInner::ByRef(from_ptr, None) => { + let from_addr = from_ptr.get_addr(fx); + let to_addr = to_ptr.get_addr(fx); + let src_layout = from.1; + 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_memory_copy( + fx.cx.module.target_config(), + to_addr, + from_addr, + size, + dst_align, + src_align, + true, + ); + } + CValueInner::ByRef(_, Some(_)) => todo!(), + } + } + + pub(crate) fn place_field( + self, + fx: &mut FunctionCx<'_, 'tcx, impl Module>, + field: mir::Field, + ) -> CPlace<'tcx> { + let layout = self.layout(); + + match self.inner { + CPlaceInner::Var(local, var) => { + if let Abi::Vector { .. } = layout.abi { + return CPlace { + inner: CPlaceInner::VarLane(local, var, field.as_u32().try_into().unwrap()), + layout: layout.field(fx, field.as_u32().try_into().unwrap()), + }; + } + } + CPlaceInner::VarPair(local, var1, var2) => { + let layout = layout.field(&*fx, field.index()); + + match field.as_u32() { + 0 => { + return CPlace { + inner: CPlaceInner::Var(local, var1), + layout, + } + } + 1 => { + return CPlace { + inner: CPlaceInner::Var(local, var2), + layout, + } + } + _ => unreachable!("field should be 0 or 1"), + } + } + _ => {} + } + + let (base, extra) = self.to_ptr_maybe_unsized(); + + let (field_ptr, field_layout) = codegen_field(fx, base, extra, layout, field); + if field_layout.is_unsized() { + CPlace::for_ptr_with_extra(field_ptr, extra.unwrap(), field_layout) + } else { + CPlace::for_ptr(field_ptr, field_layout) + } + } + + pub(crate) fn place_index( + self, + fx: &mut FunctionCx<'_, 'tcx, impl Module>, + index: Value, + ) -> CPlace<'tcx> { + let (elem_layout, ptr) = match self.layout().ty.kind() { + ty::Array(elem_ty, _) => (fx.layout_of(elem_ty), self.to_ptr()), + ty::Slice(elem_ty) => (fx.layout_of(elem_ty), self.to_ptr_maybe_unsized().0), + _ => bug!("place_index({:?})", self.layout().ty), + }; + + let offset = fx + .bcx + .ins() + .imul_imm(index, elem_layout.size.bytes() as i64); + + CPlace::for_ptr(ptr.offset_value(fx, offset), elem_layout) + } + + pub(crate) fn place_deref(self, fx: &mut FunctionCx<'_, 'tcx, impl Module>) -> CPlace<'tcx> { + let inner_layout = fx.layout_of(self.layout().ty.builtin_deref(true).unwrap().ty); + if has_ptr_meta(fx.tcx, inner_layout.ty) { + let (addr, extra) = self.to_cvalue(fx).load_scalar_pair(fx); + CPlace::for_ptr_with_extra(Pointer::new(addr), extra, inner_layout) + } else { + CPlace::for_ptr( + Pointer::new(self.to_cvalue(fx).load_scalar(fx)), + inner_layout, + ) + } + } + + pub(crate) fn place_ref( + self, + fx: &mut FunctionCx<'_, 'tcx, impl Module>, + layout: TyAndLayout<'tcx>, + ) -> CValue<'tcx> { + if has_ptr_meta(fx.tcx, self.layout().ty) { + let (ptr, extra) = self.to_ptr_maybe_unsized(); + CValue::by_val_pair( + ptr.get_addr(fx), + extra.expect("unsized type without metadata"), + layout, + ) + } else { + CValue::by_val(self.to_ptr().get_addr(fx), layout) + } + } + + pub(crate) fn downcast_variant( + self, + fx: &FunctionCx<'_, 'tcx, impl Module>, + variant: VariantIdx, + ) -> Self { + assert!(!self.layout().is_unsized()); + let layout = self.layout().for_variant(fx, variant); + CPlace { + inner: self.inner, + layout, + } + } +} |