| use rustc_abi::{self as abi, FIRST_VARIANT}; |
| use rustc_middle::ty::adjustment::PointerCoercion; |
| use rustc_middle::ty::layout::{HasTyCtxt, HasTypingEnv, LayoutOf, TyAndLayout}; |
| use rustc_middle::ty::{self, Instance, Ty, TyCtxt}; |
| use rustc_middle::{bug, mir, span_bug}; |
| use rustc_session::config::OptLevel; |
| use tracing::{debug, instrument}; |
| |
| use super::operand::{OperandRef, OperandRefBuilder, OperandValue}; |
| use super::place::{PlaceRef, PlaceValue, codegen_tag_value}; |
| use super::{FunctionCx, LocalRef}; |
| use crate::common::{IntPredicate, TypeKind}; |
| use crate::traits::*; |
| use crate::{MemFlags, base}; |
| |
| impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> { |
| #[instrument(level = "trace", skip(self, bx))] |
| pub(crate) fn codegen_rvalue( |
| &mut self, |
| bx: &mut Bx, |
| dest: PlaceRef<'tcx, Bx::Value>, |
| rvalue: &mir::Rvalue<'tcx>, |
| ) { |
| match *rvalue { |
| mir::Rvalue::Use(ref operand) => { |
| let cg_operand = self.codegen_operand(bx, operand); |
| // FIXME: consider not copying constants through stack. (Fixable by codegen'ing |
| // constants into `OperandValue::Ref`; why don’t we do that yet if we don’t?) |
| cg_operand.val.store(bx, dest); |
| } |
| |
| mir::Rvalue::Cast( |
| mir::CastKind::PointerCoercion(PointerCoercion::Unsize, _), |
| ref source, |
| _, |
| ) => { |
| // The destination necessarily contains a wide pointer, so if |
| // it's a scalar pair, it's a wide pointer or newtype thereof. |
| if bx.cx().is_backend_scalar_pair(dest.layout) { |
| // Into-coerce of a thin pointer to a wide pointer -- just |
| // use the operand path. |
| let temp = self.codegen_rvalue_operand(bx, rvalue); |
| temp.val.store(bx, dest); |
| return; |
| } |
| |
| // Unsize of a nontrivial struct. I would prefer for |
| // this to be eliminated by MIR building, but |
| // `CoerceUnsized` can be passed by a where-clause, |
| // so the (generic) MIR may not be able to expand it. |
| let operand = self.codegen_operand(bx, source); |
| match operand.val { |
| OperandValue::Pair(..) | OperandValue::Immediate(_) => { |
| // Unsize from an immediate structure. We don't |
| // really need a temporary alloca here, but |
| // avoiding it would require us to have |
| // `coerce_unsized_into` use `extractvalue` to |
| // index into the struct, and this case isn't |
| // important enough for it. |
| debug!("codegen_rvalue: creating ugly alloca"); |
| let scratch = PlaceRef::alloca(bx, operand.layout); |
| scratch.storage_live(bx); |
| operand.val.store(bx, scratch); |
| base::coerce_unsized_into(bx, scratch, dest); |
| scratch.storage_dead(bx); |
| } |
| OperandValue::Ref(val) => { |
| if val.llextra.is_some() { |
| bug!("unsized coercion on an unsized rvalue"); |
| } |
| base::coerce_unsized_into(bx, val.with_type(operand.layout), dest); |
| } |
| OperandValue::ZeroSized => { |
| bug!("unsized coercion on a ZST rvalue"); |
| } |
| } |
| } |
| |
| mir::Rvalue::Cast(mir::CastKind::Transmute, ref operand, _ty) => { |
| let src = self.codegen_operand(bx, operand); |
| self.codegen_transmute(bx, src, dest); |
| } |
| |
| mir::Rvalue::Repeat(ref elem, count) => { |
| // Do not generate the loop for zero-sized elements or empty arrays. |
| if dest.layout.is_zst() { |
| return; |
| } |
| |
| // When the element is a const with all bytes uninit, emit a single memset that |
| // writes undef to the entire destination. |
| if let mir::Operand::Constant(const_op) = elem { |
| let val = self.eval_mir_constant(const_op); |
| if val.all_bytes_uninit(self.cx.tcx()) { |
| let size = bx.const_usize(dest.layout.size.bytes()); |
| bx.memset( |
| dest.val.llval, |
| bx.const_undef(bx.type_i8()), |
| size, |
| dest.val.align, |
| MemFlags::empty(), |
| ); |
| return; |
| } |
| } |
| |
| let cg_elem = self.codegen_operand(bx, elem); |
| |
| let try_init_all_same = |bx: &mut Bx, v| { |
| let start = dest.val.llval; |
| let size = bx.const_usize(dest.layout.size.bytes()); |
| |
| // Use llvm.memset.p0i8.* to initialize all same byte arrays |
| if let Some(int) = bx.cx().const_to_opt_u128(v, false) { |
| let bytes = &int.to_le_bytes()[..cg_elem.layout.size.bytes_usize()]; |
| let first = bytes[0]; |
| if bytes[1..].iter().all(|&b| b == first) { |
| let fill = bx.cx().const_u8(first); |
| bx.memset(start, fill, size, dest.val.align, MemFlags::empty()); |
| return true; |
| } |
| } |
| |
| // Use llvm.memset.p0i8.* to initialize byte arrays |
| let v = bx.from_immediate(v); |
| if bx.cx().val_ty(v) == bx.cx().type_i8() { |
| bx.memset(start, v, size, dest.val.align, MemFlags::empty()); |
| return true; |
| } |
| false |
| }; |
| |
| match cg_elem.val { |
| OperandValue::Immediate(v) => { |
| if try_init_all_same(bx, v) { |
| return; |
| } |
| } |
| _ => (), |
| } |
| |
| let count = self |
| .monomorphize(count) |
| .try_to_target_usize(bx.tcx()) |
| .expect("expected monomorphic const in codegen"); |
| |
| bx.write_operand_repeatedly(cg_elem, count, dest); |
| } |
| |
| // This implementation does field projection, so never use it for `RawPtr`, |
| // which will always be fine with the `codegen_rvalue_operand` path below. |
| mir::Rvalue::Aggregate(ref kind, ref operands) |
| if !matches!(**kind, mir::AggregateKind::RawPtr(..)) => |
| { |
| let (variant_index, variant_dest, active_field_index) = match **kind { |
| mir::AggregateKind::Adt(_, variant_index, _, _, active_field_index) => { |
| let variant_dest = dest.project_downcast(bx, variant_index); |
| (variant_index, variant_dest, active_field_index) |
| } |
| _ => (FIRST_VARIANT, dest, None), |
| }; |
| if active_field_index.is_some() { |
| assert_eq!(operands.len(), 1); |
| } |
| for (i, operand) in operands.iter_enumerated() { |
| let op = self.codegen_operand(bx, operand); |
| // Do not generate stores and GEPis for zero-sized fields. |
| if !op.layout.is_zst() { |
| let field_index = active_field_index.unwrap_or(i); |
| let field = if let mir::AggregateKind::Array(_) = **kind { |
| let llindex = bx.cx().const_usize(field_index.as_u32().into()); |
| variant_dest.project_index(bx, llindex) |
| } else { |
| variant_dest.project_field(bx, field_index.as_usize()) |
| }; |
| op.val.store(bx, field); |
| } |
| } |
| dest.codegen_set_discr(bx, variant_index); |
| } |
| |
| _ => { |
| let temp = self.codegen_rvalue_operand(bx, rvalue); |
| temp.val.store(bx, dest); |
| } |
| } |
| } |
| |
| /// Transmutes the `src` value to the destination type by writing it to `dst`. |
| /// |
| /// See also [`Self::codegen_transmute_operand`] for cases that can be done |
| /// without needing a pre-allocated place for the destination. |
| fn codegen_transmute( |
| &mut self, |
| bx: &mut Bx, |
| src: OperandRef<'tcx, Bx::Value>, |
| dst: PlaceRef<'tcx, Bx::Value>, |
| ) { |
| // The MIR validator enforces no unsized transmutes. |
| assert!(src.layout.is_sized()); |
| assert!(dst.layout.is_sized()); |
| |
| if src.layout.size != dst.layout.size |
| || src.layout.is_uninhabited() |
| || dst.layout.is_uninhabited() |
| { |
| // These cases are all UB to actually hit, so don't emit code for them. |
| // (The size mismatches are reachable via `transmute_unchecked`.) |
| bx.unreachable_nonterminator(); |
| } else { |
| // Since in this path we have a place anyway, we can store or copy to it, |
| // making sure we use the destination place's alignment even if the |
| // source would normally have a higher one. |
| src.val.store(bx, dst.val.with_type(src.layout)); |
| } |
| } |
| |
| /// Transmutes an `OperandValue` to another `OperandValue`. |
| /// |
| /// This is supported for all cases where the `cast` type is SSA, |
| /// but for non-ZSTs with [`abi::BackendRepr::Memory`] it ICEs. |
| pub(crate) fn codegen_transmute_operand( |
| &mut self, |
| bx: &mut Bx, |
| operand: OperandRef<'tcx, Bx::Value>, |
| cast: TyAndLayout<'tcx>, |
| ) -> OperandValue<Bx::Value> { |
| if let abi::BackendRepr::Memory { .. } = cast.backend_repr |
| && !cast.is_zst() |
| { |
| span_bug!(self.mir.span, "Use `codegen_transmute` to transmute to {cast:?}"); |
| } |
| |
| // `Layout` is interned, so we can do a cheap check for things that are |
| // exactly the same and thus don't need any handling. |
| if abi::Layout::eq(&operand.layout.layout, &cast.layout) { |
| return operand.val; |
| } |
| |
| // Check for transmutes that are always UB. |
| if operand.layout.size != cast.size |
| || operand.layout.is_uninhabited() |
| || cast.is_uninhabited() |
| { |
| bx.unreachable_nonterminator(); |
| |
| // We still need to return a value of the appropriate type, but |
| // it's already UB so do the easiest thing available. |
| return OperandValue::poison(bx, cast); |
| } |
| |
| // To or from pointers takes different methods, so we use this to restrict |
| // the SimdVector case to types which can be `bitcast` between each other. |
| #[inline] |
| fn vector_can_bitcast(x: abi::Scalar) -> bool { |
| matches!( |
| x, |
| abi::Scalar::Initialized { |
| value: abi::Primitive::Int(..) | abi::Primitive::Float(..), |
| .. |
| } |
| ) |
| } |
| |
| let cx = bx.cx(); |
| match (operand.val, operand.layout.backend_repr, cast.backend_repr) { |
| _ if cast.is_zst() => OperandValue::ZeroSized, |
| (OperandValue::Ref(source_place_val), abi::BackendRepr::Memory { .. }, _) => { |
| assert_eq!(source_place_val.llextra, None); |
| // The existing alignment is part of `source_place_val`, |
| // so that alignment will be used, not `cast`'s. |
| bx.load_operand(source_place_val.with_type(cast)).val |
| } |
| ( |
| OperandValue::Immediate(imm), |
| abi::BackendRepr::Scalar(from_scalar), |
| abi::BackendRepr::Scalar(to_scalar), |
| ) if from_scalar.size(cx) == to_scalar.size(cx) => { |
| OperandValue::Immediate(transmute_scalar(bx, imm, from_scalar, to_scalar)) |
| } |
| ( |
| OperandValue::Immediate(imm), |
| abi::BackendRepr::SimdVector { element: from_scalar, .. }, |
| abi::BackendRepr::SimdVector { element: to_scalar, .. }, |
| ) if vector_can_bitcast(from_scalar) && vector_can_bitcast(to_scalar) => { |
| let to_backend_ty = bx.cx().immediate_backend_type(cast); |
| OperandValue::Immediate(bx.bitcast(imm, to_backend_ty)) |
| } |
| ( |
| OperandValue::Pair(imm_a, imm_b), |
| abi::BackendRepr::ScalarPair(in_a, in_b), |
| abi::BackendRepr::ScalarPair(out_a, out_b), |
| ) if in_a.size(cx) == out_a.size(cx) && in_b.size(cx) == out_b.size(cx) => { |
| OperandValue::Pair( |
| transmute_scalar(bx, imm_a, in_a, out_a), |
| transmute_scalar(bx, imm_b, in_b, out_b), |
| ) |
| } |
| _ => { |
| // For any other potentially-tricky cases, make a temporary instead. |
| // If anything else wants the target local to be in memory this won't |
| // be hit, as `codegen_transmute` will get called directly. Thus this |
| // is only for places where everything else wants the operand form, |
| // and thus it's not worth making those places get it from memory. |
| // |
| // Notably, Scalar ⇌ ScalarPair cases go here to avoid padding |
| // and endianness issues, as do SimdVector ones to avoid worrying |
| // about things like f32x8 ⇌ ptrx4 that would need multiple steps. |
| let align = Ord::max(operand.layout.align.abi, cast.align.abi); |
| let size = Ord::max(operand.layout.size, cast.size); |
| let temp = PlaceValue::alloca(bx, size, align); |
| bx.lifetime_start(temp.llval, size); |
| operand.val.store(bx, temp.with_type(operand.layout)); |
| let val = bx.load_operand(temp.with_type(cast)).val; |
| bx.lifetime_end(temp.llval, size); |
| val |
| } |
| } |
| } |
| |
| /// Cast one of the immediates from an [`OperandValue::Immediate`] |
| /// or an [`OperandValue::Pair`] to an immediate of the target type. |
| /// |
| /// Returns `None` if the cast is not possible. |
| fn cast_immediate( |
| &self, |
| bx: &mut Bx, |
| mut imm: Bx::Value, |
| from_scalar: abi::Scalar, |
| from_backend_ty: Bx::Type, |
| to_scalar: abi::Scalar, |
| to_backend_ty: Bx::Type, |
| ) -> Option<Bx::Value> { |
| use abi::Primitive::*; |
| |
| // When scalars are passed by value, there's no metadata recording their |
| // valid ranges. For example, `char`s are passed as just `i32`, with no |
| // way for LLVM to know that they're 0x10FFFF at most. Thus we assume |
| // the range of the input value too, not just the output range. |
| assume_scalar_range(bx, imm, from_scalar, from_backend_ty, None); |
| |
| imm = match (from_scalar.primitive(), to_scalar.primitive()) { |
| (Int(_, is_signed), Int(..)) => bx.intcast(imm, to_backend_ty, is_signed), |
| (Float(_), Float(_)) => { |
| let srcsz = bx.cx().float_width(from_backend_ty); |
| let dstsz = bx.cx().float_width(to_backend_ty); |
| if dstsz > srcsz { |
| bx.fpext(imm, to_backend_ty) |
| } else if srcsz > dstsz { |
| bx.fptrunc(imm, to_backend_ty) |
| } else { |
| imm |
| } |
| } |
| (Int(_, is_signed), Float(_)) => { |
| if is_signed { |
| bx.sitofp(imm, to_backend_ty) |
| } else { |
| bx.uitofp(imm, to_backend_ty) |
| } |
| } |
| (Pointer(..), Pointer(..)) => bx.pointercast(imm, to_backend_ty), |
| (Int(_, is_signed), Pointer(..)) => { |
| let usize_imm = bx.intcast(imm, bx.cx().type_isize(), is_signed); |
| bx.inttoptr(usize_imm, to_backend_ty) |
| } |
| (Float(_), Int(_, is_signed)) => bx.cast_float_to_int(is_signed, imm, to_backend_ty), |
| _ => return None, |
| }; |
| Some(imm) |
| } |
| |
| pub(crate) fn codegen_rvalue_operand( |
| &mut self, |
| bx: &mut Bx, |
| rvalue: &mir::Rvalue<'tcx>, |
| ) -> OperandRef<'tcx, Bx::Value> { |
| match *rvalue { |
| mir::Rvalue::Cast(ref kind, ref source, mir_cast_ty) => { |
| let operand = self.codegen_operand(bx, source); |
| debug!("cast operand is {:?}", operand); |
| let cast = bx.cx().layout_of(self.monomorphize(mir_cast_ty)); |
| |
| let val = match *kind { |
| mir::CastKind::PointerExposeProvenance => { |
| assert!(bx.cx().is_backend_immediate(cast)); |
| let llptr = operand.immediate(); |
| let llcast_ty = bx.cx().immediate_backend_type(cast); |
| let lladdr = bx.ptrtoint(llptr, llcast_ty); |
| OperandValue::Immediate(lladdr) |
| } |
| mir::CastKind::PointerCoercion(PointerCoercion::ReifyFnPointer, _) => { |
| match *operand.layout.ty.kind() { |
| ty::FnDef(def_id, args) => { |
| let instance = ty::Instance::resolve_for_fn_ptr( |
| bx.tcx(), |
| bx.typing_env(), |
| def_id, |
| args, |
| ) |
| .unwrap(); |
| OperandValue::Immediate(bx.get_fn_addr(instance)) |
| } |
| _ => bug!("{} cannot be reified to a fn ptr", operand.layout.ty), |
| } |
| } |
| mir::CastKind::PointerCoercion(PointerCoercion::ClosureFnPointer(_), _) => { |
| match *operand.layout.ty.kind() { |
| ty::Closure(def_id, args) => { |
| let instance = Instance::resolve_closure( |
| bx.cx().tcx(), |
| def_id, |
| args, |
| ty::ClosureKind::FnOnce, |
| ); |
| OperandValue::Immediate(bx.cx().get_fn_addr(instance)) |
| } |
| _ => bug!("{} cannot be cast to a fn ptr", operand.layout.ty), |
| } |
| } |
| mir::CastKind::PointerCoercion(PointerCoercion::UnsafeFnPointer, _) => { |
| // This is a no-op at the LLVM level. |
| operand.val |
| } |
| mir::CastKind::PointerCoercion(PointerCoercion::Unsize, _) => { |
| assert!(bx.cx().is_backend_scalar_pair(cast)); |
| let (lldata, llextra) = operand.val.pointer_parts(); |
| let (lldata, llextra) = |
| base::unsize_ptr(bx, lldata, operand.layout.ty, cast.ty, llextra); |
| OperandValue::Pair(lldata, llextra) |
| } |
| mir::CastKind::PointerCoercion( |
| PointerCoercion::MutToConstPointer | PointerCoercion::ArrayToPointer, _ |
| ) => { |
| bug!("{kind:?} is for borrowck, and should never appear in codegen"); |
| } |
| mir::CastKind::PtrToPtr |
| if bx.cx().is_backend_scalar_pair(operand.layout) => |
| { |
| if let OperandValue::Pair(data_ptr, meta) = operand.val { |
| if bx.cx().is_backend_scalar_pair(cast) { |
| OperandValue::Pair(data_ptr, meta) |
| } else { |
| // Cast of wide-ptr to thin-ptr is an extraction of data-ptr. |
| OperandValue::Immediate(data_ptr) |
| } |
| } else { |
| bug!("unexpected non-pair operand"); |
| } |
| } |
| | mir::CastKind::IntToInt |
| | mir::CastKind::FloatToInt |
| | mir::CastKind::FloatToFloat |
| | mir::CastKind::IntToFloat |
| | mir::CastKind::PtrToPtr |
| | mir::CastKind::FnPtrToPtr |
| // Since int2ptr can have arbitrary integer types as input (so we have to do |
| // sign extension and all that), it is currently best handled in the same code |
| // path as the other integer-to-X casts. |
| | mir::CastKind::PointerWithExposedProvenance => { |
| let imm = operand.immediate(); |
| let abi::BackendRepr::Scalar(from_scalar) = operand.layout.backend_repr else { |
| bug!("Found non-scalar for operand {operand:?}"); |
| }; |
| let from_backend_ty = bx.cx().immediate_backend_type(operand.layout); |
| |
| assert!(bx.cx().is_backend_immediate(cast)); |
| let to_backend_ty = bx.cx().immediate_backend_type(cast); |
| if operand.layout.is_uninhabited() { |
| let val = OperandValue::Immediate(bx.cx().const_poison(to_backend_ty)); |
| return OperandRef { val, layout: cast }; |
| } |
| let abi::BackendRepr::Scalar(to_scalar) = cast.layout.backend_repr else { |
| bug!("Found non-scalar for cast {cast:?}"); |
| }; |
| |
| self.cast_immediate(bx, imm, from_scalar, from_backend_ty, to_scalar, to_backend_ty) |
| .map(OperandValue::Immediate) |
| .unwrap_or_else(|| { |
| bug!("Unsupported cast of {operand:?} to {cast:?}"); |
| }) |
| } |
| mir::CastKind::Transmute => { |
| self.codegen_transmute_operand(bx, operand, cast) |
| } |
| }; |
| OperandRef { val, layout: cast } |
| } |
| |
| mir::Rvalue::Ref(_, bk, place) => { |
| let mk_ref = move |tcx: TyCtxt<'tcx>, ty: Ty<'tcx>| { |
| Ty::new_ref(tcx, tcx.lifetimes.re_erased, ty, bk.to_mutbl_lossy()) |
| }; |
| self.codegen_place_to_pointer(bx, place, mk_ref) |
| } |
| |
| mir::Rvalue::CopyForDeref(place) => { |
| self.codegen_operand(bx, &mir::Operand::Copy(place)) |
| } |
| mir::Rvalue::RawPtr(kind, place) => { |
| let mk_ptr = move |tcx: TyCtxt<'tcx>, ty: Ty<'tcx>| { |
| Ty::new_ptr(tcx, ty, kind.to_mutbl_lossy()) |
| }; |
| self.codegen_place_to_pointer(bx, place, mk_ptr) |
| } |
| |
| mir::Rvalue::Len(place) => { |
| let size = self.evaluate_array_len(bx, place); |
| OperandRef { |
| val: OperandValue::Immediate(size), |
| layout: bx.cx().layout_of(bx.tcx().types.usize), |
| } |
| } |
| |
| mir::Rvalue::BinaryOp(op_with_overflow, box (ref lhs, ref rhs)) |
| if let Some(op) = op_with_overflow.overflowing_to_wrapping() => |
| { |
| let lhs = self.codegen_operand(bx, lhs); |
| let rhs = self.codegen_operand(bx, rhs); |
| let result = self.codegen_scalar_checked_binop( |
| bx, |
| op, |
| lhs.immediate(), |
| rhs.immediate(), |
| lhs.layout.ty, |
| ); |
| let val_ty = op.ty(bx.tcx(), lhs.layout.ty, rhs.layout.ty); |
| let operand_ty = Ty::new_tup(bx.tcx(), &[val_ty, bx.tcx().types.bool]); |
| OperandRef { val: result, layout: bx.cx().layout_of(operand_ty) } |
| } |
| mir::Rvalue::BinaryOp(op, box (ref lhs, ref rhs)) => { |
| let lhs = self.codegen_operand(bx, lhs); |
| let rhs = self.codegen_operand(bx, rhs); |
| let llresult = match (lhs.val, rhs.val) { |
| ( |
| OperandValue::Pair(lhs_addr, lhs_extra), |
| OperandValue::Pair(rhs_addr, rhs_extra), |
| ) => self.codegen_wide_ptr_binop( |
| bx, |
| op, |
| lhs_addr, |
| lhs_extra, |
| rhs_addr, |
| rhs_extra, |
| lhs.layout.ty, |
| ), |
| |
| (OperandValue::Immediate(lhs_val), OperandValue::Immediate(rhs_val)) => self |
| .codegen_scalar_binop( |
| bx, |
| op, |
| lhs_val, |
| rhs_val, |
| lhs.layout.ty, |
| rhs.layout.ty, |
| ), |
| |
| _ => bug!(), |
| }; |
| OperandRef { |
| val: OperandValue::Immediate(llresult), |
| layout: bx.cx().layout_of(op.ty(bx.tcx(), lhs.layout.ty, rhs.layout.ty)), |
| } |
| } |
| |
| mir::Rvalue::UnaryOp(op, ref operand) => { |
| let operand = self.codegen_operand(bx, operand); |
| let is_float = operand.layout.ty.is_floating_point(); |
| let (val, layout) = match op { |
| mir::UnOp::Not => { |
| let llval = bx.not(operand.immediate()); |
| (OperandValue::Immediate(llval), operand.layout) |
| } |
| mir::UnOp::Neg => { |
| let llval = if is_float { |
| bx.fneg(operand.immediate()) |
| } else { |
| bx.neg(operand.immediate()) |
| }; |
| (OperandValue::Immediate(llval), operand.layout) |
| } |
| mir::UnOp::PtrMetadata => { |
| assert!(operand.layout.ty.is_raw_ptr() || operand.layout.ty.is_ref(),); |
| let (_, meta) = operand.val.pointer_parts(); |
| assert_eq!(operand.layout.fields.count() > 1, meta.is_some()); |
| if let Some(meta) = meta { |
| (OperandValue::Immediate(meta), operand.layout.field(self.cx, 1)) |
| } else { |
| (OperandValue::ZeroSized, bx.cx().layout_of(bx.tcx().types.unit)) |
| } |
| } |
| }; |
| assert!( |
| val.is_expected_variant_for_type(self.cx, layout), |
| "Made wrong variant {val:?} for type {layout:?}", |
| ); |
| OperandRef { val, layout } |
| } |
| |
| mir::Rvalue::Discriminant(ref place) => { |
| let discr_ty = rvalue.ty(self.mir, bx.tcx()); |
| let discr_ty = self.monomorphize(discr_ty); |
| let operand = self.codegen_consume(bx, place.as_ref()); |
| let discr = operand.codegen_get_discr(self, bx, discr_ty); |
| OperandRef { |
| val: OperandValue::Immediate(discr), |
| layout: self.cx.layout_of(discr_ty), |
| } |
| } |
| |
| mir::Rvalue::NullaryOp(ref null_op, ty) => { |
| let ty = self.monomorphize(ty); |
| let layout = bx.cx().layout_of(ty); |
| let val = match null_op { |
| mir::NullOp::SizeOf => { |
| assert!(bx.cx().type_is_sized(ty)); |
| let val = layout.size.bytes(); |
| bx.cx().const_usize(val) |
| } |
| mir::NullOp::AlignOf => { |
| assert!(bx.cx().type_is_sized(ty)); |
| let val = layout.align.abi.bytes(); |
| bx.cx().const_usize(val) |
| } |
| mir::NullOp::OffsetOf(fields) => { |
| let val = bx |
| .tcx() |
| .offset_of_subfield(bx.typing_env(), layout, fields.iter()) |
| .bytes(); |
| bx.cx().const_usize(val) |
| } |
| mir::NullOp::UbChecks => { |
| let val = bx.tcx().sess.ub_checks(); |
| bx.cx().const_bool(val) |
| } |
| mir::NullOp::ContractChecks => { |
| let val = bx.tcx().sess.contract_checks(); |
| bx.cx().const_bool(val) |
| } |
| }; |
| let tcx = self.cx.tcx(); |
| OperandRef { |
| val: OperandValue::Immediate(val), |
| layout: self.cx.layout_of(null_op.ty(tcx)), |
| } |
| } |
| |
| mir::Rvalue::ThreadLocalRef(def_id) => { |
| assert!(bx.cx().tcx().is_static(def_id)); |
| let layout = bx.layout_of(bx.cx().tcx().static_ptr_ty(def_id, bx.typing_env())); |
| let static_ = if !def_id.is_local() && bx.cx().tcx().needs_thread_local_shim(def_id) |
| { |
| let instance = ty::Instance { |
| def: ty::InstanceKind::ThreadLocalShim(def_id), |
| args: ty::GenericArgs::empty(), |
| }; |
| let fn_ptr = bx.get_fn_addr(instance); |
| let fn_abi = bx.fn_abi_of_instance(instance, ty::List::empty()); |
| let fn_ty = bx.fn_decl_backend_type(fn_abi); |
| let fn_attrs = if bx.tcx().def_kind(instance.def_id()).has_codegen_attrs() { |
| Some(bx.tcx().codegen_instance_attrs(instance.def)) |
| } else { |
| None |
| }; |
| bx.call( |
| fn_ty, |
| fn_attrs.as_deref(), |
| Some(fn_abi), |
| fn_ptr, |
| &[], |
| None, |
| Some(instance), |
| ) |
| } else { |
| bx.get_static(def_id) |
| }; |
| OperandRef { val: OperandValue::Immediate(static_), layout } |
| } |
| mir::Rvalue::Use(ref operand) => self.codegen_operand(bx, operand), |
| mir::Rvalue::Repeat(ref elem, len_const) => { |
| // All arrays have `BackendRepr::Memory`, so only the ZST cases |
| // end up here. Anything else forces the destination local to be |
| // `Memory`, and thus ends up handled in `codegen_rvalue` instead. |
| let operand = self.codegen_operand(bx, elem); |
| let array_ty = Ty::new_array_with_const_len(bx.tcx(), operand.layout.ty, len_const); |
| let array_ty = self.monomorphize(array_ty); |
| let array_layout = bx.layout_of(array_ty); |
| assert!(array_layout.is_zst()); |
| OperandRef { val: OperandValue::ZeroSized, layout: array_layout } |
| } |
| mir::Rvalue::Aggregate(ref kind, ref fields) => { |
| let (variant_index, active_field_index) = match **kind { |
| mir::AggregateKind::Adt(_, variant_index, _, _, active_field_index) => { |
| (variant_index, active_field_index) |
| } |
| _ => (FIRST_VARIANT, None), |
| }; |
| |
| let ty = rvalue.ty(self.mir, self.cx.tcx()); |
| let ty = self.monomorphize(ty); |
| let layout = self.cx.layout_of(ty); |
| |
| let mut builder = OperandRefBuilder::new(layout); |
| for (field_idx, field) in fields.iter_enumerated() { |
| let op = self.codegen_operand(bx, field); |
| let fi = active_field_index.unwrap_or(field_idx); |
| builder.insert_field(bx, variant_index, fi, op); |
| } |
| |
| let tag_result = codegen_tag_value(self.cx, variant_index, layout); |
| match tag_result { |
| Err(super::place::UninhabitedVariantError) => { |
| // Like codegen_set_discr we use a sound abort, but could |
| // potentially `unreachable` or just return the poison for |
| // more optimizability, if that turns out to be helpful. |
| bx.abort(); |
| let val = OperandValue::poison(bx, layout); |
| OperandRef { val, layout } |
| } |
| Ok(maybe_tag_value) => { |
| if let Some((tag_field, tag_imm)) = maybe_tag_value { |
| builder.insert_imm(tag_field, tag_imm); |
| } |
| builder.build(bx.cx()) |
| } |
| } |
| } |
| mir::Rvalue::ShallowInitBox(ref operand, content_ty) => { |
| let operand = self.codegen_operand(bx, operand); |
| let val = operand.immediate(); |
| |
| let content_ty = self.monomorphize(content_ty); |
| let box_layout = bx.cx().layout_of(Ty::new_box(bx.tcx(), content_ty)); |
| |
| OperandRef { val: OperandValue::Immediate(val), layout: box_layout } |
| } |
| mir::Rvalue::WrapUnsafeBinder(ref operand, binder_ty) => { |
| let operand = self.codegen_operand(bx, operand); |
| let binder_ty = self.monomorphize(binder_ty); |
| let layout = bx.cx().layout_of(binder_ty); |
| OperandRef { val: operand.val, layout } |
| } |
| } |
| } |
| |
| fn evaluate_array_len(&mut self, bx: &mut Bx, place: mir::Place<'tcx>) -> Bx::Value { |
| // ZST are passed as operands and require special handling |
| // because codegen_place() panics if Local is operand. |
| if let Some(index) = place.as_local() |
| && let LocalRef::Operand(op) = self.locals[index] |
| && let ty::Array(_, n) = op.layout.ty.kind() |
| { |
| let n = n.try_to_target_usize(bx.tcx()).expect("expected monomorphic const in codegen"); |
| return bx.cx().const_usize(n); |
| } |
| // use common size calculation for non zero-sized types |
| let cg_value = self.codegen_place(bx, place.as_ref()); |
| cg_value.len(bx.cx()) |
| } |
| |
| /// Codegen an `Rvalue::RawPtr` or `Rvalue::Ref` |
| fn codegen_place_to_pointer( |
| &mut self, |
| bx: &mut Bx, |
| place: mir::Place<'tcx>, |
| mk_ptr_ty: impl FnOnce(TyCtxt<'tcx>, Ty<'tcx>) -> Ty<'tcx>, |
| ) -> OperandRef<'tcx, Bx::Value> { |
| let cg_place = self.codegen_place(bx, place.as_ref()); |
| let val = cg_place.val.address(); |
| |
| let ty = cg_place.layout.ty; |
| assert!( |
| if bx.cx().tcx().type_has_metadata(ty, bx.cx().typing_env()) { |
| matches!(val, OperandValue::Pair(..)) |
| } else { |
| matches!(val, OperandValue::Immediate(..)) |
| }, |
| "Address of place was unexpectedly {val:?} for pointee type {ty:?}", |
| ); |
| |
| OperandRef { val, layout: self.cx.layout_of(mk_ptr_ty(self.cx.tcx(), ty)) } |
| } |
| |
| fn codegen_scalar_binop( |
| &mut self, |
| bx: &mut Bx, |
| op: mir::BinOp, |
| lhs: Bx::Value, |
| rhs: Bx::Value, |
| lhs_ty: Ty<'tcx>, |
| rhs_ty: Ty<'tcx>, |
| ) -> Bx::Value { |
| let is_float = lhs_ty.is_floating_point(); |
| let is_signed = lhs_ty.is_signed(); |
| match op { |
| mir::BinOp::Add => { |
| if is_float { |
| bx.fadd(lhs, rhs) |
| } else { |
| bx.add(lhs, rhs) |
| } |
| } |
| mir::BinOp::AddUnchecked => { |
| if is_signed { |
| bx.unchecked_sadd(lhs, rhs) |
| } else { |
| bx.unchecked_uadd(lhs, rhs) |
| } |
| } |
| mir::BinOp::Sub => { |
| if is_float { |
| bx.fsub(lhs, rhs) |
| } else { |
| bx.sub(lhs, rhs) |
| } |
| } |
| mir::BinOp::SubUnchecked => { |
| if is_signed { |
| bx.unchecked_ssub(lhs, rhs) |
| } else { |
| bx.unchecked_usub(lhs, rhs) |
| } |
| } |
| mir::BinOp::Mul => { |
| if is_float { |
| bx.fmul(lhs, rhs) |
| } else { |
| bx.mul(lhs, rhs) |
| } |
| } |
| mir::BinOp::MulUnchecked => { |
| if is_signed { |
| bx.unchecked_smul(lhs, rhs) |
| } else { |
| bx.unchecked_umul(lhs, rhs) |
| } |
| } |
| mir::BinOp::Div => { |
| if is_float { |
| bx.fdiv(lhs, rhs) |
| } else if is_signed { |
| bx.sdiv(lhs, rhs) |
| } else { |
| bx.udiv(lhs, rhs) |
| } |
| } |
| mir::BinOp::Rem => { |
| if is_float { |
| bx.frem(lhs, rhs) |
| } else if is_signed { |
| bx.srem(lhs, rhs) |
| } else { |
| bx.urem(lhs, rhs) |
| } |
| } |
| mir::BinOp::BitOr => bx.or(lhs, rhs), |
| mir::BinOp::BitAnd => bx.and(lhs, rhs), |
| mir::BinOp::BitXor => bx.xor(lhs, rhs), |
| mir::BinOp::Offset => { |
| let pointee_type = lhs_ty |
| .builtin_deref(true) |
| .unwrap_or_else(|| bug!("deref of non-pointer {:?}", lhs_ty)); |
| let pointee_layout = bx.cx().layout_of(pointee_type); |
| if pointee_layout.is_zst() { |
| // `Offset` works in terms of the size of pointee, |
| // so offsetting a pointer to ZST is a noop. |
| lhs |
| } else { |
| let llty = bx.cx().backend_type(pointee_layout); |
| if !rhs_ty.is_signed() { |
| bx.inbounds_nuw_gep(llty, lhs, &[rhs]) |
| } else { |
| bx.inbounds_gep(llty, lhs, &[rhs]) |
| } |
| } |
| } |
| mir::BinOp::Shl | mir::BinOp::ShlUnchecked => { |
| let rhs = base::build_shift_expr_rhs(bx, lhs, rhs, op == mir::BinOp::ShlUnchecked); |
| bx.shl(lhs, rhs) |
| } |
| mir::BinOp::Shr | mir::BinOp::ShrUnchecked => { |
| let rhs = base::build_shift_expr_rhs(bx, lhs, rhs, op == mir::BinOp::ShrUnchecked); |
| if is_signed { bx.ashr(lhs, rhs) } else { bx.lshr(lhs, rhs) } |
| } |
| mir::BinOp::Ne |
| | mir::BinOp::Lt |
| | mir::BinOp::Gt |
| | mir::BinOp::Eq |
| | mir::BinOp::Le |
| | mir::BinOp::Ge => { |
| if is_float { |
| bx.fcmp(base::bin_op_to_fcmp_predicate(op), lhs, rhs) |
| } else { |
| bx.icmp(base::bin_op_to_icmp_predicate(op, is_signed), lhs, rhs) |
| } |
| } |
| mir::BinOp::Cmp => { |
| use std::cmp::Ordering; |
| assert!(!is_float); |
| if let Some(value) = bx.three_way_compare(lhs_ty, lhs, rhs) { |
| return value; |
| } |
| let pred = |op| base::bin_op_to_icmp_predicate(op, is_signed); |
| if bx.cx().tcx().sess.opts.optimize == OptLevel::No { |
| // FIXME: This actually generates tighter assembly, and is a classic trick |
| // <https://graphics.stanford.edu/~seander/bithacks.html#CopyIntegerSign> |
| // However, as of 2023-11 it optimizes worse in things like derived |
| // `PartialOrd`, so only use it in debug for now. Once LLVM can handle it |
| // better (see <https://github.com/llvm/llvm-project/issues/73417>), it'll |
| // be worth trying it in optimized builds as well. |
| let is_gt = bx.icmp(pred(mir::BinOp::Gt), lhs, rhs); |
| let gtext = bx.zext(is_gt, bx.type_i8()); |
| let is_lt = bx.icmp(pred(mir::BinOp::Lt), lhs, rhs); |
| let ltext = bx.zext(is_lt, bx.type_i8()); |
| bx.unchecked_ssub(gtext, ltext) |
| } else { |
| // These operations are those expected by `tests/codegen-llvm/integer-cmp.rs`, |
| // from <https://github.com/rust-lang/rust/pull/63767>. |
| let is_lt = bx.icmp(pred(mir::BinOp::Lt), lhs, rhs); |
| let is_ne = bx.icmp(pred(mir::BinOp::Ne), lhs, rhs); |
| let ge = bx.select( |
| is_ne, |
| bx.cx().const_i8(Ordering::Greater as i8), |
| bx.cx().const_i8(Ordering::Equal as i8), |
| ); |
| bx.select(is_lt, bx.cx().const_i8(Ordering::Less as i8), ge) |
| } |
| } |
| mir::BinOp::AddWithOverflow |
| | mir::BinOp::SubWithOverflow |
| | mir::BinOp::MulWithOverflow => { |
| bug!("{op:?} needs to return a pair, so call codegen_scalar_checked_binop instead") |
| } |
| } |
| } |
| |
| fn codegen_wide_ptr_binop( |
| &mut self, |
| bx: &mut Bx, |
| op: mir::BinOp, |
| lhs_addr: Bx::Value, |
| lhs_extra: Bx::Value, |
| rhs_addr: Bx::Value, |
| rhs_extra: Bx::Value, |
| _input_ty: Ty<'tcx>, |
| ) -> Bx::Value { |
| match op { |
| mir::BinOp::Eq => { |
| let lhs = bx.icmp(IntPredicate::IntEQ, lhs_addr, rhs_addr); |
| let rhs = bx.icmp(IntPredicate::IntEQ, lhs_extra, rhs_extra); |
| bx.and(lhs, rhs) |
| } |
| mir::BinOp::Ne => { |
| let lhs = bx.icmp(IntPredicate::IntNE, lhs_addr, rhs_addr); |
| let rhs = bx.icmp(IntPredicate::IntNE, lhs_extra, rhs_extra); |
| bx.or(lhs, rhs) |
| } |
| mir::BinOp::Le | mir::BinOp::Lt | mir::BinOp::Ge | mir::BinOp::Gt => { |
| // a OP b ~ a.0 STRICT(OP) b.0 | (a.0 == b.0 && a.1 OP a.1) |
| let (op, strict_op) = match op { |
| mir::BinOp::Lt => (IntPredicate::IntULT, IntPredicate::IntULT), |
| mir::BinOp::Le => (IntPredicate::IntULE, IntPredicate::IntULT), |
| mir::BinOp::Gt => (IntPredicate::IntUGT, IntPredicate::IntUGT), |
| mir::BinOp::Ge => (IntPredicate::IntUGE, IntPredicate::IntUGT), |
| _ => bug!(), |
| }; |
| let lhs = bx.icmp(strict_op, lhs_addr, rhs_addr); |
| let and_lhs = bx.icmp(IntPredicate::IntEQ, lhs_addr, rhs_addr); |
| let and_rhs = bx.icmp(op, lhs_extra, rhs_extra); |
| let rhs = bx.and(and_lhs, and_rhs); |
| bx.or(lhs, rhs) |
| } |
| _ => { |
| bug!("unexpected wide ptr binop"); |
| } |
| } |
| } |
| |
| fn codegen_scalar_checked_binop( |
| &mut self, |
| bx: &mut Bx, |
| op: mir::BinOp, |
| lhs: Bx::Value, |
| rhs: Bx::Value, |
| input_ty: Ty<'tcx>, |
| ) -> OperandValue<Bx::Value> { |
| let (val, of) = match op { |
| // These are checked using intrinsics |
| mir::BinOp::Add | mir::BinOp::Sub | mir::BinOp::Mul => { |
| let oop = match op { |
| mir::BinOp::Add => OverflowOp::Add, |
| mir::BinOp::Sub => OverflowOp::Sub, |
| mir::BinOp::Mul => OverflowOp::Mul, |
| _ => unreachable!(), |
| }; |
| bx.checked_binop(oop, input_ty, lhs, rhs) |
| } |
| _ => bug!("Operator `{:?}` is not a checkable operator", op), |
| }; |
| |
| OperandValue::Pair(val, of) |
| } |
| } |
| |
| /// Transmutes a single scalar value `imm` from `from_scalar` to `to_scalar`. |
| /// |
| /// This is expected to be in *immediate* form, as seen in [`OperandValue::Immediate`] |
| /// or [`OperandValue::Pair`] (so `i1` for bools, not `i8`, for example). |
| /// |
| /// ICEs if the passed-in `imm` is not a value of the expected type for |
| /// `from_scalar`, such as if it's a vector or a pair. |
| pub(super) fn transmute_scalar<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>( |
| bx: &mut Bx, |
| mut imm: Bx::Value, |
| from_scalar: abi::Scalar, |
| to_scalar: abi::Scalar, |
| ) -> Bx::Value { |
| assert_eq!(from_scalar.size(bx.cx()), to_scalar.size(bx.cx())); |
| let imm_ty = bx.cx().val_ty(imm); |
| assert_ne!( |
| bx.cx().type_kind(imm_ty), |
| TypeKind::Vector, |
| "Vector type {imm_ty:?} not allowed in transmute_scalar {from_scalar:?} -> {to_scalar:?}" |
| ); |
| |
| // While optimizations will remove no-op transmutes, they might still be |
| // there in debug or things that aren't no-op in MIR because they change |
| // the Rust type but not the underlying layout/niche. |
| if from_scalar == to_scalar { |
| return imm; |
| } |
| |
| use abi::Primitive::*; |
| imm = bx.from_immediate(imm); |
| |
| let from_backend_ty = bx.cx().type_from_scalar(from_scalar); |
| debug_assert_eq!(bx.cx().val_ty(imm), from_backend_ty); |
| let to_backend_ty = bx.cx().type_from_scalar(to_scalar); |
| |
| // If we have a scalar, we must already know its range. Either |
| // |
| // 1) It's a parameter with `range` parameter metadata, |
| // 2) It's something we `load`ed with `!range` metadata, or |
| // 3) After a transmute we `assume`d the range (see below). |
| // |
| // That said, last time we tried removing this, it didn't actually help |
| // the rustc-perf results, so might as well keep doing it |
| // <https://github.com/rust-lang/rust/pull/135610#issuecomment-2599275182> |
| assume_scalar_range(bx, imm, from_scalar, from_backend_ty, Some(&to_scalar)); |
| |
| imm = match (from_scalar.primitive(), to_scalar.primitive()) { |
| (Int(..) | Float(_), Int(..) | Float(_)) => bx.bitcast(imm, to_backend_ty), |
| (Pointer(..), Pointer(..)) => bx.pointercast(imm, to_backend_ty), |
| (Int(..), Pointer(..)) => bx.ptradd(bx.const_null(bx.type_ptr()), imm), |
| (Pointer(..), Int(..)) => { |
| // FIXME: this exposes the provenance, which shouldn't be necessary. |
| bx.ptrtoint(imm, to_backend_ty) |
| } |
| (Float(_), Pointer(..)) => { |
| let int_imm = bx.bitcast(imm, bx.cx().type_isize()); |
| bx.ptradd(bx.const_null(bx.type_ptr()), int_imm) |
| } |
| (Pointer(..), Float(_)) => { |
| // FIXME: this exposes the provenance, which shouldn't be necessary. |
| let int_imm = bx.ptrtoint(imm, bx.cx().type_isize()); |
| bx.bitcast(int_imm, to_backend_ty) |
| } |
| }; |
| |
| debug_assert_eq!(bx.cx().val_ty(imm), to_backend_ty); |
| |
| // This `assume` remains important for cases like (a conceptual) |
| // transmute::<u32, NonZeroU32>(x) == 0 |
| // since it's never passed to something with parameter metadata (especially |
| // after MIR inlining) so the only way to tell the backend about the |
| // constraint that the `transmute` introduced is to `assume` it. |
| assume_scalar_range(bx, imm, to_scalar, to_backend_ty, Some(&from_scalar)); |
| |
| imm = bx.to_immediate_scalar(imm, to_scalar); |
| imm |
| } |
| |
| /// Emits an `assume` call that `imm`'s value is within the known range of `scalar`. |
| /// |
| /// If `known` is `Some`, only emits the assume if it's more specific than |
| /// whatever is already known from the range of *that* scalar. |
| fn assume_scalar_range<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>( |
| bx: &mut Bx, |
| imm: Bx::Value, |
| scalar: abi::Scalar, |
| backend_ty: Bx::Type, |
| known: Option<&abi::Scalar>, |
| ) { |
| if matches!(bx.cx().sess().opts.optimize, OptLevel::No) { |
| return; |
| } |
| |
| match (scalar, known) { |
| (abi::Scalar::Union { .. }, _) => return, |
| (_, None) => { |
| if scalar.is_always_valid(bx.cx()) { |
| return; |
| } |
| } |
| (abi::Scalar::Initialized { valid_range, .. }, Some(known)) => { |
| let known_range = known.valid_range(bx.cx()); |
| if valid_range.contains_range(known_range, scalar.size(bx.cx())) { |
| return; |
| } |
| } |
| } |
| |
| match scalar.primitive() { |
| abi::Primitive::Int(..) => { |
| let range = scalar.valid_range(bx.cx()); |
| bx.assume_integer_range(imm, backend_ty, range); |
| } |
| abi::Primitive::Pointer(abi::AddressSpace::ZERO) |
| if !scalar.valid_range(bx.cx()).contains(0) => |
| { |
| bx.assume_nonnull(imm); |
| } |
| abi::Primitive::Pointer(..) | abi::Primitive::Float(..) => {} |
| } |
| } |
