bjoernager/rust
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always use gep inbounds i8 (ptradd) for field offsets

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This commit is contained in:
Erik Desjardins 2024-02-23 23:23:35 -05:00
parent 71ffdf7ff7
commit 123015e722
8 changed files with 11 additions and 63 deletions
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34
compiler/rustc_codegen_ssa/src/mir/place.rs
View file

@ -9,7 +9,7 @@ use rustc_middle::mir;
use rustc_middle::mir::tcx::PlaceTy;
use rustc_middle::ty::layout::{HasTyCtxt, LayoutOf, TyAndLayout};
use rustc_middle::ty::{self, Ty};
use rustc_target::abi::{Abi, Align, FieldsShape, Int, Pointer, TagEncoding};
use rustc_target::abi::{Align, FieldsShape, Int, Pointer, TagEncoding};
use rustc_target::abi::{VariantIdx, Variants};
#[derive(Copy, Clone, Debug)]
@ -102,34 +102,10 @@ impl<'a, 'tcx, V: CodegenObject> PlaceRef<'tcx, V> {
// `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 => {
// Unions and newtypes only use an offset of 0.
// Also handles the first field of Scalar, ScalarPair, and Vector layouts.
self.llval
}
Abi::ScalarPair(..) => {
// FIXME(nikic): Generate this for all ABIs.
bx.inbounds_gep(bx.type_i8(), self.llval, &[bx.const_usize(offset.bytes())])
}
Abi::Scalar(_) | Abi::Vector { .. } if field.is_zst() => {
// ZST fields (even some that require alignment) are not included in Scalar,
// ScalarPair, and Vector layouts, so manually offset the pointer.
bx.gep(bx.cx().type_i8(), self.llval, &[bx.const_usize(offset.bytes())])
}
Abi::Scalar(_) => {
// All fields of Scalar layouts must have been handled by this point.
// Vector layouts have additional fields for each element of the vector, so don't panic in that case.
bug!(
"offset of non-ZST field `{:?}` does not match layout `{:#?}`",
field,
self.layout
);
}
_ => {
let ty = bx.backend_type(self.layout);
bx.struct_gep(ty, self.llval, bx.cx().backend_field_index(self.layout, ix))
}
let llval = if offset.bytes() == 0 {
self.llval
} else {
bx.inbounds_gep(bx.type_i8(), self.llval, &[bx.const_usize(offset.bytes())])
};
PlaceRef {
llval,

1
compiler/rustc_codegen_ssa/src/traits/type_.rs
View file

@ -111,7 +111,6 @@ pub trait LayoutTypeMethods<'tcx>: Backend<'tcx> {
fn immediate_backend_type(&self, layout: TyAndLayout<'tcx>) -> Self::Type;
fn is_backend_immediate(&self, layout: TyAndLayout<'tcx>) -> bool;
fn is_backend_scalar_pair(&self, layout: TyAndLayout<'tcx>) -> bool;
fn backend_field_index(&self, layout: TyAndLayout<'tcx>, index: usize) -> u64;
fn scalar_pair_element_backend_type(
&self,
layout: TyAndLayout<'tcx>,