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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-06-19 09:26:03 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-06-19 09:26:03 +0000 |
commit | 9918693037dce8aa4bb6f08741b6812923486c18 (patch) | |
tree | 21d2b40bec7e6a7ea664acee056eb3d08e15a1cf /compiler/rustc_codegen_ssa/src/mir/place.rs | |
parent | Releasing progress-linux version 1.75.0+dfsg1-5~progress7.99u1. (diff) | |
download | rustc-9918693037dce8aa4bb6f08741b6812923486c18.tar.xz rustc-9918693037dce8aa4bb6f08741b6812923486c18.zip |
Merging upstream version 1.76.0+dfsg1.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'compiler/rustc_codegen_ssa/src/mir/place.rs')
-rw-r--r-- | compiler/rustc_codegen_ssa/src/mir/place.rs | 55 |
1 files changed, 25 insertions, 30 deletions
diff --git a/compiler/rustc_codegen_ssa/src/mir/place.rs b/compiler/rustc_codegen_ssa/src/mir/place.rs index eb590a45a..c0bb3ac56 100644 --- a/compiler/rustc_codegen_ssa/src/mir/place.rs +++ b/compiler/rustc_codegen_ssa/src/mir/place.rs @@ -2,7 +2,7 @@ use super::operand::OperandValue; use super::{FunctionCx, LocalRef}; use crate::common::IntPredicate; -use crate::glue; +use crate::size_of_val; use crate::traits::*; use rustc_middle::mir; @@ -99,6 +99,8 @@ impl<'a, 'tcx, V: CodegenObject> PlaceRef<'tcx, V> { let offset = self.layout.fields.offset(ix); let effective_field_align = self.align.restrict_for_offset(offset); + // `simple` is called when we don't need to adjust the offset to + // the dynamic alignment of the field. let mut simple = || { let llval = match self.layout.abi { _ if offset.bytes() == 0 => { @@ -141,35 +143,21 @@ impl<'a, 'tcx, V: CodegenObject> PlaceRef<'tcx, V> { }; // Simple cases, which don't need DST adjustment: - // * no metadata available - just log the case - // * known alignment - sized types, `[T]`, `str` or a foreign type - // * packed struct - there is no alignment padding + // * known alignment - sized types, `[T]`, `str` + // * offset 0 -- rounding up to alignment cannot change the offset + // Note that looking at `field.align` is incorrect since that is not necessarily equal + // to the dynamic alignment of the type. match field.ty.kind() { - _ if self.llextra.is_none() => { - debug!( - "unsized field `{}`, of `{:?}` has no metadata for adjustment", - ix, self.llval - ); - return simple(); - } _ if field.is_sized() => return simple(), - ty::Slice(..) | ty::Str | ty::Foreign(..) => return simple(), - ty::Adt(def, _) => { - if def.repr().packed() { - // FIXME(eddyb) generalize the adjustment when we - // start supporting packing to larger alignments. - assert_eq!(self.layout.align.abi.bytes(), 1); - return simple(); - } - } + ty::Slice(..) | ty::Str => return simple(), + _ if offset.bytes() == 0 => return simple(), _ => {} } // We need to get the pointer manually now. // We do this by casting to a `*i8`, then offsetting it by the appropriate amount. // We do this instead of, say, simply adjusting the pointer from the result of a GEP - // because the field may have an arbitrary alignment in the LLVM representation - // anyway. + // because the field may have an arbitrary alignment in the LLVM representation. // // To demonstrate: // @@ -186,7 +174,16 @@ impl<'a, 'tcx, V: CodegenObject> PlaceRef<'tcx, V> { let unaligned_offset = bx.cx().const_usize(offset.bytes()); // Get the alignment of the field - let (_, unsized_align) = glue::size_and_align_of_dst(bx, field.ty, meta); + let (_, mut unsized_align) = size_of_val::size_and_align_of_dst(bx, field.ty, meta); + + // For packed types, we need to cap alignment. + if let ty::Adt(def, _) = self.layout.ty.kind() + && let Some(packed) = def.repr().pack + { + let packed = bx.const_usize(packed.bytes()); + let cmp = bx.icmp(IntPredicate::IntULT, unsized_align, packed); + unsized_align = bx.select(cmp, unsized_align, packed) + } // Bump the unaligned offset up to the appropriate alignment let offset = round_up_const_value_to_alignment(bx, unaligned_offset, unsized_align); @@ -474,27 +471,25 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> { cg_base.project_index(bx, llindex) } mir::ProjectionElem::ConstantIndex { offset, from_end: false, min_length: _ } => { - let lloffset = bx.cx().const_usize(offset as u64); + let lloffset = bx.cx().const_usize(offset); cg_base.project_index(bx, lloffset) } mir::ProjectionElem::ConstantIndex { offset, from_end: true, min_length: _ } => { - let lloffset = bx.cx().const_usize(offset as u64); + let lloffset = bx.cx().const_usize(offset); let lllen = cg_base.len(bx.cx()); let llindex = bx.sub(lllen, lloffset); cg_base.project_index(bx, llindex) } mir::ProjectionElem::Subslice { from, to, from_end } => { - let mut subslice = cg_base.project_index(bx, bx.cx().const_usize(from as u64)); + let mut subslice = cg_base.project_index(bx, bx.cx().const_usize(from)); let projected_ty = PlaceTy::from_ty(cg_base.layout.ty).projection_ty(tcx, *elem).ty; subslice.layout = bx.cx().layout_of(self.monomorphize(projected_ty)); if subslice.layout.is_unsized() { assert!(from_end, "slice subslices should be `from_end`"); - subslice.llextra = Some(bx.sub( - cg_base.llextra.unwrap(), - bx.cx().const_usize((from as u64) + (to as u64)), - )); + subslice.llextra = + Some(bx.sub(cg_base.llextra.unwrap(), bx.cx().const_usize(from + to))); } subslice |