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Clean up matches that determine integers for specific alignment requirements

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This commit is contained in:
Austin Hicks 2016-09-24 17:37:24 -04:00
parent 4038189688
commit 12ff05fc50
2 changed files with 31 additions and 23 deletions
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37
src/librustc/ty/layout.rs
View File

@ -339,6 +339,16 @@ pub fn size(&self) -> Size {
}
}
pub fn align(&self, dl: &TargetDataLayout)-> Align {
match *self {
I1 => dl.i1_align,
I8 => dl.i8_align,
I16 => dl.i16_align,
I32 => dl.i32_align,
I64 => dl.i64_align,
}
}
pub fn to_ty<'a, 'tcx>(&self, tcx: &ty::TyCtxt<'a, 'tcx, 'tcx>,
signed: bool) -> Ty<'tcx> {
match (*self, signed) {
@ -377,6 +387,18 @@ pub fn fit_unsigned(x: u64) -> Integer {
}
}
//Find the smallest integer with the given alignment.
pub fn for_abi_align(dl: &TargetDataLayout, align: Align) -> Option<Integer> {
let wanted = align.abi();
for &candidate in &[I8, I16, I32, I64] {
let ty = Int(candidate);
if wanted == ty.align(dl).abi() && wanted == ty.size(dl).bytes() {
return Some(candidate);
}
}
None
}
/// Get the Integer type from an attr::IntType.
pub fn from_attr(dl: &TargetDataLayout, ity: attr::IntType) -> Integer {
match ity {
@ -1149,20 +1171,7 @@ pub fn compute_uncached(ty: Ty<'gcx>,
// won't be so conservative.
// Use the initial field alignment
let wanted = start_align.abi();
let mut ity = min_ity;
for &candidate in &[I16, I32, I64] {
let ty = Int(candidate);
if wanted == ty.align(dl).abi() && wanted == ty.size(dl).bytes() {
ity = candidate;
break;
}
}
// FIXME(eddyb) conservative only to avoid diverging from trans::adt.
if align.abi() != start_align.abi() {
ity = min_ity;
}
let mut ity = Integer::for_abi_align(dl, start_align).unwrap_or(min_ity);
// If the alignment is not larger than the chosen discriminant size,
// don't use the alignment as the final size.

17
src/librustc_trans/adt.rs
View File

@ -286,16 +286,15 @@ fn generic_type_of<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
fn union_fill(cx: &CrateContext, size: u64, align: u64) -> Type {
assert_eq!(size%align, 0);
assert_eq!(align.count_ones(), 1, "Alignment must be a power fof 2. Got {}", align);
let align_units = size/align;
match align {
1 => Type::array(&Type::i8(cx), align_units),
2 => Type::array(&Type::i16(cx), align_units),
4 => Type::array(&Type::i32(cx), align_units),
8 if machine::llalign_of_min(cx, Type::i64(cx)) == 8 =>
Type::array(&Type::i64(cx), align_units),
a if a.count_ones() == 1 => Type::array(&Type::vector(&Type::i32(cx), a / 4),
align_units),
_ => bug!("unsupported union alignment: {}", align)
let dl = &cx.tcx().data_layout;
let layout_align = layout::Align::from_bytes(align, align).unwrap();
if let Some(ity) = layout::Integer::for_abi_align(dl, layout_align) {
Type::array(&Type::from_integer(cx, ity), align_units)
} else {
Type::array(&Type::vector(&Type::i32(cx), align/4),
align_units)
}
}