diff --git a/compiler/rustc_middle/src/ty/layout.rs b/compiler/rustc_middle/src/ty/layout.rs index 0363f4d7cdac..566bf70a3d26 100644 --- a/compiler/rustc_middle/src/ty/layout.rs +++ b/compiler/rustc_middle/src/ty/layout.rs @@ -2514,7 +2514,7 @@ where extra_args: &[Ty<'tcx>], caller_location: Option>, codegen_fn_attr_flags: CodegenFnAttrFlags, - mk_arg_type: impl Fn(Ty<'tcx>, Option) -> ArgAbi<'tcx, Ty<'tcx>>, + make_self_ptr_thin: bool, ) -> Self; fn adjust_for_abi(&mut self, cx: &C, abi: SpecAbi); } @@ -2574,9 +2574,7 @@ where // Assume that fn pointers may always unwind let codegen_fn_attr_flags = CodegenFnAttrFlags::UNWIND; - call::FnAbi::new_internal(cx, sig, extra_args, None, codegen_fn_attr_flags, |ty, _| { - ArgAbi::new(cx.layout_of(ty)) - }) + call::FnAbi::new_internal(cx, sig, extra_args, None, codegen_fn_attr_flags, false) } fn of_instance(cx: &C, instance: ty::Instance<'tcx>, extra_args: &[Ty<'tcx>]) -> Self { @@ -2590,55 +2588,14 @@ where let attrs = cx.tcx().codegen_fn_attrs(instance.def_id()).flags; - call::FnAbi::new_internal(cx, sig, extra_args, caller_location, attrs, |ty, arg_idx| { - let mut layout = cx.layout_of(ty); - // Don't pass the vtable, it's not an argument of the virtual fn. - // Instead, pass just the data pointer, but give it the type `*const/mut dyn Trait` - // or `&/&mut dyn Trait` because this is special-cased elsewhere in codegen - if let (ty::InstanceDef::Virtual(..), Some(0)) = (&instance.def, arg_idx) { - let fat_pointer_ty = if layout.is_unsized() { - // unsized `self` is passed as a pointer to `self` - // FIXME (mikeyhew) change this to use &own if it is ever added to the language - cx.tcx().mk_mut_ptr(layout.ty) - } else { - match layout.abi { - Abi::ScalarPair(..) => (), - _ => bug!("receiver type has unsupported layout: {:?}", layout), - } - - // In the case of Rc, we need to explicitly pass a *mut RcBox - // with a Scalar (not ScalarPair) ABI. This is a hack that is understood - // elsewhere in the compiler as a method on a `dyn Trait`. - // To get the type `*mut RcBox`, we just keep unwrapping newtypes until we - // get a built-in pointer type - let mut fat_pointer_layout = layout; - 'descend_newtypes: while !fat_pointer_layout.ty.is_unsafe_ptr() - && !fat_pointer_layout.ty.is_region_ptr() - { - for i in 0..fat_pointer_layout.fields.count() { - let field_layout = fat_pointer_layout.field(cx, i); - - if !field_layout.is_zst() { - fat_pointer_layout = field_layout; - continue 'descend_newtypes; - } - } - - bug!("receiver has no non-zero-sized fields {:?}", fat_pointer_layout); - } - - fat_pointer_layout.ty - }; - - // we now have a type like `*mut RcBox` - // change its layout to that of `*mut ()`, a thin pointer, but keep the same type - // this is understood as a special case elsewhere in the compiler - let unit_pointer_ty = cx.tcx().mk_mut_ptr(cx.tcx().mk_unit()); - layout = cx.layout_of(unit_pointer_ty); - layout.ty = fat_pointer_ty; - } - ArgAbi::new(layout) - }) + call::FnAbi::new_internal( + cx, + sig, + extra_args, + caller_location, + attrs, + matches!(instance.def, ty::InstanceDef::Virtual(..)), + ) } fn new_internal( @@ -2647,7 +2604,7 @@ where extra_args: &[Ty<'tcx>], caller_location: Option>, codegen_fn_attr_flags: CodegenFnAttrFlags, - mk_arg_type: impl Fn(Ty<'tcx>, Option) -> ArgAbi<'tcx, Ty<'tcx>>, + force_thin_self_ptr: bool, ) -> Self { debug!("FnAbi::new_internal({:?}, {:?})", sig, extra_args); @@ -2778,7 +2735,18 @@ where let arg_of = |ty: Ty<'tcx>, arg_idx: Option| { let is_return = arg_idx.is_none(); - let mut arg = mk_arg_type(ty, arg_idx); + + let layout = if force_thin_self_ptr && arg_idx == Some(0) { + // Don't pass the vtable, it's not an argument of the virtual fn. + // Instead, pass just the data pointer, but give it the type `*const/mut dyn Trait` + // or `&/&mut dyn Trait` because this is special-cased elsewhere in codegen + make_thin_self_ptr(cx, cx.layout_of(ty)) + } else { + cx.layout_of(ty) + }; + + let mut arg = ArgAbi::new(layout); + if arg.layout.is_zst() { // For some forsaken reason, x86_64-pc-windows-gnu // doesn't ignore zero-sized struct arguments. @@ -2912,3 +2880,56 @@ where } } } + +fn make_thin_self_ptr<'tcx, C>( + cx: &C, + mut layout: TyAndLayout<'tcx>, +) -> TyAndLayout<'tcx> +where C: LayoutOf, TyAndLayout = TyAndLayout<'tcx>> + //+ HasDataLayout + //+ HasTargetSpec + + HasTyCtxt<'tcx> + + HasParamEnv<'tcx> +{ + let fat_pointer_ty = if layout.is_unsized() { + // unsized `self` is passed as a pointer to `self` + // FIXME (mikeyhew) change this to use &own if it is ever added to the language + cx.tcx().mk_mut_ptr(layout.ty) + } else { + match layout.abi { + Abi::ScalarPair(..) => (), + _ => bug!("receiver type has unsupported layout: {:?}", layout), + } + + // In the case of Rc, we need to explicitly pass a *mut RcBox + // with a Scalar (not ScalarPair) ABI. This is a hack that is understood + // elsewhere in the compiler as a method on a `dyn Trait`. + // To get the type `*mut RcBox`, we just keep unwrapping newtypes until we + // get a built-in pointer type + let mut fat_pointer_layout = layout; + 'descend_newtypes: while !fat_pointer_layout.ty.is_unsafe_ptr() + && !fat_pointer_layout.ty.is_region_ptr() + { + for i in 0..fat_pointer_layout.fields.count() { + let field_layout = fat_pointer_layout.field(cx, i); + + if !field_layout.is_zst() { + fat_pointer_layout = field_layout; + continue 'descend_newtypes; + } + } + + bug!("receiver has no non-zero-sized fields {:?}", fat_pointer_layout); + } + + fat_pointer_layout.ty + }; + + // we now have a type like `*mut RcBox` + // change its layout to that of `*mut ()`, a thin pointer, but keep the same type + // this is understood as a special case elsewhere in the compiler + let unit_pointer_ty = cx.tcx().mk_mut_ptr(cx.tcx().mk_unit()); + layout = cx.layout_of(unit_pointer_ty); + layout.ty = fat_pointer_ty; + layout +}