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Update Cargo.lock and move size_and_align_of_dst back
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| Original file line number | Diff line number | Diff line change |
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| // Copyright 2012-2013 The Rust Project Developers. See the COPYRIGHT | ||
| // file at the top-level directory of this distribution and at | ||
| // http://rust-lang.org/COPYRIGHT. | ||
| // | ||
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or | ||
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license | ||
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your | ||
| // option. This file may not be copied, modified, or distributed | ||
| // except according to those terms. | ||
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| //! | ||
| // | ||
| // Code relating to drop glue. | ||
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| use std; | ||
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| use builder::Builder; | ||
| use common::*; | ||
| use llvm::{ValueRef}; | ||
| use llvm; | ||
| use meth; | ||
| use rustc::ty::layout::LayoutOf; | ||
| use rustc::ty::{self, Ty}; | ||
| use value::Value; | ||
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| pub fn size_and_align_of_dst<'a, 'tcx>(bx: &Builder<'a, 'tcx>, t: Ty<'tcx>, info: ValueRef) | ||
| -> (ValueRef, ValueRef) { | ||
| debug!("calculate size of DST: {}; with lost info: {:?}", | ||
| t, Value(info)); | ||
| if bx.cx.type_is_sized(t) { | ||
| let (size, align) = bx.cx.size_and_align_of(t); | ||
| debug!("size_and_align_of_dst t={} info={:?} size: {:?} align: {:?}", | ||
| t, Value(info), size, align); | ||
| let size = C_usize(bx.cx, size.bytes()); | ||
| let align = C_usize(bx.cx, align.abi()); | ||
| return (size, align); | ||
| } | ||
| assert!(!info.is_null()); | ||
| match t.sty { | ||
| ty::TyDynamic(..) => { | ||
| // load size/align from vtable | ||
| (meth::SIZE.get_usize(bx, info), meth::ALIGN.get_usize(bx, info)) | ||
| } | ||
| ty::TySlice(_) | ty::TyStr => { | ||
| let unit = t.sequence_element_type(bx.tcx()); | ||
| // The info in this case is the length of the str, so the size is that | ||
| // times the unit size. | ||
| let (size, align) = bx.cx.size_and_align_of(unit); | ||
| (bx.mul(info, C_usize(bx.cx, size.bytes())), | ||
| C_usize(bx.cx, align.abi())) | ||
| } | ||
| _ => { | ||
| let cx = bx.cx; | ||
| // First get the size of all statically known fields. | ||
| // Don't use size_of because it also rounds up to alignment, which we | ||
| // want to avoid, as the unsized field's alignment could be smaller. | ||
| assert!(!t.is_simd()); | ||
| let layout = cx.layout_of(t); | ||
| debug!("DST {} layout: {:?}", t, layout); | ||
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| let i = layout.fields.count() - 1; | ||
| let sized_size = layout.fields.offset(i).bytes(); | ||
| let sized_align = layout.align.abi(); | ||
| debug!("DST {} statically sized prefix size: {} align: {}", | ||
| t, sized_size, sized_align); | ||
| let sized_size = C_usize(cx, sized_size); | ||
| let sized_align = C_usize(cx, sized_align); | ||
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| // Recurse to get the size of the dynamically sized field (must be | ||
| // the last field). | ||
| let field_ty = layout.field(cx, i).ty; | ||
| let (unsized_size, mut unsized_align) = size_and_align_of_dst(bx, field_ty, info); | ||
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| // FIXME (#26403, #27023): We should be adding padding | ||
| // to `sized_size` (to accommodate the `unsized_align` | ||
| // required of the unsized field that follows) before | ||
| // summing it with `sized_size`. (Note that since #26403 | ||
| // is unfixed, we do not yet add the necessary padding | ||
| // here. But this is where the add would go.) | ||
|
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| // Return the sum of sizes and max of aligns. | ||
| let size = bx.add(sized_size, unsized_size); | ||
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| // Packed types ignore the alignment of their fields. | ||
| if let ty::TyAdt(def, _) = t.sty { | ||
| if def.repr.packed() { | ||
| unsized_align = sized_align; | ||
| } | ||
| } | ||
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| // Choose max of two known alignments (combined value must | ||
| // be aligned according to more restrictive of the two). | ||
| let align = match (const_to_opt_u128(sized_align, false), | ||
| const_to_opt_u128(unsized_align, false)) { | ||
| (Some(sized_align), Some(unsized_align)) => { | ||
| // If both alignments are constant, (the sized_align should always be), then | ||
| // pick the correct alignment statically. | ||
| C_usize(cx, std::cmp::max(sized_align, unsized_align) as u64) | ||
| } | ||
| _ => bx.select(bx.icmp(llvm::IntUGT, sized_align, unsized_align), | ||
| sized_align, | ||
| unsized_align) | ||
| }; | ||
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| // Issue #27023: must add any necessary padding to `size` | ||
| // (to make it a multiple of `align`) before returning it. | ||
| // | ||
| // Namely, the returned size should be, in C notation: | ||
| // | ||
| // `size + ((size & (align-1)) ? align : 0)` | ||
| // | ||
| // emulated via the semi-standard fast bit trick: | ||
| // | ||
| // `(size + (align-1)) & -align` | ||
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| let addend = bx.sub(align, C_usize(bx.cx, 1)); | ||
| let size = bx.and(bx.add(size, addend), bx.neg(align)); | ||
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| (size, align) | ||
| } | ||
| } | ||
| } |
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