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Deduplicate writing null case of struct wrapped nullable pointers

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This commit is contained in:
Oliver Schneider 2017-08-28 15:27:50 +02:00
parent 3464401576
commit e53e9b9e63
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GPG key ID: A69F8D225B3AD7D9
2 changed files with 36 additions and 36 deletions
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51
src/librustc_mir/interpret/eval_context.rs
View file

@ -767,25 +767,11 @@ impl<'a, 'tcx, M: Machine<'tcx>> EvalContext<'a, 'tcx, M> {
let operand_ty = self.operand_ty(operand);
assert_eq!(self.type_size(operand_ty)?, Some(0));
}
let (offset, TyAndPacked { ty, packed: _ }) =
self.nonnull_offset_and_ty(
dest_ty,
nndiscr,
discrfield_source,
)?;
// TODO: The packed flag is ignored
// FIXME(solson)
let dest = self.force_allocation(dest)?.to_ptr()?;
let dest = dest.offset(offset.bytes(), &self)?;
let dest_size = self.type_size(ty)?.expect(
"bad StructWrappedNullablePointer discrfield",
);
self.memory.write_maybe_aligned_mut(
!nonnull.packed,
// The sign does not matter for 0
|mem| mem.write_primval(dest, PrimVal::Bytes(0), dest_size, false),
self.write_struct_wrapped_null_pointer(
dest_ty,
nndiscr,
discrfield_source,
dest,
)?;
}
} else {
@ -1021,6 +1007,33 @@ impl<'a, 'tcx, M: Machine<'tcx>> EvalContext<'a, 'tcx, M> {
Ok(())
}
pub(crate) fn write_struct_wrapped_null_pointer(
&mut self,
dest_ty: ty::Ty<'tcx>,
nndiscr: u64,
discrfield_source: &layout::FieldPath,
dest: Lvalue,
) -> EvalResult<'tcx> {
let (offset, TyAndPacked { ty, packed }) = self.nonnull_offset_and_ty(
dest_ty,
nndiscr,
discrfield_source,
)?;
let nonnull = self.force_allocation(dest)?.to_ptr()?.offset(
offset.bytes(),
&self,
)?;
trace!("struct wrapped nullable pointer type: {}", ty);
// only the pointer part of a fat pointer is used for this space optimization
let discr_size = self.type_size(ty)?.expect(
"bad StructWrappedNullablePointer discrfield",
);
self.memory.write_maybe_aligned_mut(!packed, |mem| {
// We're writing 0, signedness does not matter
mem.write_primval(nonnull, PrimVal::Bytes(0), discr_size, false)
})
}
pub(super) fn type_is_fat_ptr(&self, ty: Ty<'tcx>) -> bool {
match ty.sty {
ty::TyRawPtr(ref tam) |

21
src/librustc_mir/interpret/step.rs
View file

@ -11,8 +11,8 @@ use rustc::ty;
use rustc::ty::layout::Layout;
use rustc::ty::subst::Substs;
use super::{EvalResult, EvalContext, StackPopCleanup, TyAndPacked, PtrAndAlign, GlobalId, Lvalue,
HasMemory, MemoryKind, Machine, PrimVal};
use super::{EvalResult, EvalContext, StackPopCleanup, PtrAndAlign, GlobalId, Lvalue,
MemoryKind, Machine, PrimVal};
use syntax::codemap::Span;
use syntax::ast::Mutability;
@ -125,26 +125,13 @@ impl<'a, 'tcx, M: Machine<'tcx>> EvalContext<'a, 'tcx, M> {
ref discrfield_source,
..
} => {
// TODO: There's some duplication between here and eval_rvalue_into_lvalue
if variant_index as u64 != nndiscr {
let (offset, TyAndPacked { ty, packed }) = self.nonnull_offset_and_ty(
self.write_struct_wrapped_null_pointer(
dest_ty,
nndiscr,
discrfield_source,
dest,
)?;
let nonnull = self.force_allocation(dest)?.to_ptr()?.offset(
offset.bytes(),
&self,
)?;
trace!("struct wrapped nullable pointer type: {}", ty);
// only the pointer part of a fat pointer is used for this space optimization
let discr_size = self.type_size(ty)?.expect(
"bad StructWrappedNullablePointer discrfield",
);
self.write_maybe_aligned_mut(!packed, |ectx| {
// We're writing 0, signedness does not matter
ectx.memory.write_primval(nonnull, PrimVal::Bytes(0), discr_size, false)
})?;
}
}