diff options
Diffstat (limited to 'compiler/rustc_middle/src')
| -rw-r--r-- | compiler/rustc_middle/src/ty/layout.rs | 163 |
1 files changed, 81 insertions, 82 deletions
diff --git a/compiler/rustc_middle/src/ty/layout.rs b/compiler/rustc_middle/src/ty/layout.rs index 195e840866a..ef467ed6514 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<Ty<'tcx>>, codegen_fn_attr_flags: CodegenFnAttrFlags, - mk_arg_type: impl Fn(Ty<'tcx>, Option<usize>) -> 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<Self>, we need to explicitly pass a *mut RcBox<Self> - // 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<Self>`, 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<dyn Trait>` - // 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<Ty<'tcx>>, codegen_fn_attr_flags: CodegenFnAttrFlags, - mk_arg_type: impl Fn(Ty<'tcx>, Option<usize>) -> ArgAbi<'tcx, Ty<'tcx>>, + force_thin_self_ptr: bool, ) -> Self { debug!("FnAbi::new_internal({:?}, {:?})", sig, extra_args); @@ -2778,7 +2735,23 @@ where let arg_of = |ty: Ty<'tcx>, arg_idx: Option<usize>| { let is_return = arg_idx.is_none(); - let mut arg = mk_arg_type(ty, arg_idx); + + let layout = cx.layout_of(ty); + 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, layout) + } else { + layout + }; + + let mut arg = ArgAbi::new(cx, layout, |layout, scalar, offset| { + let mut attrs = ArgAttributes::new(); + adjust_for_rust_scalar(&mut attrs, scalar, *layout, offset, is_return); + attrs + }); + if arg.layout.is_zst() { // For some forsaken reason, x86_64-pc-windows-gnu // doesn't ignore zero-sized struct arguments. @@ -2794,30 +2767,6 @@ where } } - // FIXME(eddyb) other ABIs don't have logic for scalar pairs. - if !is_return && rust_abi { - if let Abi::ScalarPair(ref a, ref b) = arg.layout.abi { - let mut a_attrs = ArgAttributes::new(); - let mut b_attrs = ArgAttributes::new(); - adjust_for_rust_scalar(&mut a_attrs, a, arg.layout, Size::ZERO, false); - adjust_for_rust_scalar( - &mut b_attrs, - b, - arg.layout, - a.value.size(cx).align_to(b.value.align(cx).abi), - false, - ); - arg.mode = PassMode::Pair(a_attrs, b_attrs); - return arg; - } - } - - if let Abi::Scalar(ref scalar) = arg.layout.abi { - if let PassMode::Direct(ref mut attrs) = arg.mode { - adjust_for_rust_scalar(attrs, scalar, arg.layout, Size::ZERO, is_return); - } - } - arg }; @@ -2894,9 +2843,10 @@ where let max_by_val_size = Pointer.size(cx) * 2; let size = arg.layout.size; - if arg.layout.is_unsized() || size > max_by_val_size { - arg.make_indirect(); - } else { + let is_indirect_not_on_stack = + matches!(arg.mode, PassMode::Indirect { on_stack: false, .. }); + assert!(is_indirect_not_on_stack, "{:?}", arg); + if !arg.layout.is_unsized() && size <= max_by_val_size { // We want to pass small aggregates as immediates, but using // a LLVM aggregate type for this leads to bad optimizations, // so we pick an appropriately sized integer type instead. @@ -2915,3 +2865,52 @@ where } } } + +fn make_thin_self_ptr<'tcx, C>(cx: &C, mut layout: TyAndLayout<'tcx>) -> TyAndLayout<'tcx> +where + C: LayoutOf<Ty = Ty<'tcx>, TyAndLayout = TyAndLayout<'tcx>> + + 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<Self>, we need to explicitly pass a *mut RcBox<Self> + // 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<Self>`, 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<dyn Trait>` + // 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 +} |