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Do not force_allocate Deref base.

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This makes `eval_lvalue` a bit less DRY for now, but it will be easier
to remove force_allocate in more places piecewise.
This commit is contained in:
Scott Olson 2016-10-16 02:57:59 -06:00
parent e4f5b4b39a
commit 55f2164bcd
1 changed files with 27 additions and 6 deletions

33
src/interpreter/mod.rs

@ -889,17 +889,16 @@ impl<'a, 'tcx> EvalContext<'a, 'tcx> {
proj: &mir::LvalueProjection<'tcx>,
) -> EvalResult<'tcx, Lvalue> {
let base = self.eval_lvalue(&proj.base)?;
// FIXME(solson): Is this always necessary?
let base = self.force_allocation(base)?;
let (base_ptr, base_extra) = base.to_ptr_and_extra();
let base_ty = self.lvalue_ty(&proj.base);
let base_layout = self.type_layout(base_ty);
use rustc::mir::repr::ProjectionElem::*;
let (ptr, extra) = match proj.elem {
Field(field, field_ty) => {
// FIXME(solson)
let base = self.force_allocation(base)?;
let (base_ptr, base_extra) = base.to_ptr_and_extra();
let field_ty = self.monomorphize(field_ty, self.substs());
let field = field.index();
@ -946,6 +945,10 @@ impl<'a, 'tcx> EvalContext<'a, 'tcx> {
}
Downcast(_, variant) => {
// FIXME(solson)
let base = self.force_allocation(base)?;
let (base_ptr, base_extra) = base.to_ptr_and_extra();
use rustc::ty::layout::Layout::*;
let extra = match *base_layout {
General { .. } => LvalueExtra::DowncastVariant(variant),
@ -958,7 +961,13 @@ impl<'a, 'tcx> EvalContext<'a, 'tcx> {
Deref => {
use primval::PrimVal::*;
use interpreter::value::Value::*;
match self.read_value(base_ptr, base_ty)? {
let val = match self.eval_and_read_lvalue(&proj.base)? {
ByRef(ptr) => self.read_value(ptr, base_ty)?,
v => v,
};
match val {
ByValPair(Ptr(ptr), Ptr(vptr)) => (ptr, LvalueExtra::Vtable(vptr)),
ByValPair(Ptr(ptr), n) =>
(ptr, LvalueExtra::Length(n.expect_uint("slice length"))),
@ -968,6 +977,10 @@ impl<'a, 'tcx> EvalContext<'a, 'tcx> {
}
Index(ref operand) => {
// FIXME(solson)
let base = self.force_allocation(base)?;
let (base_ptr, _) = base.to_ptr_and_extra();
let (elem_ty, len) = base.elem_ty_and_len(base_ty);
let elem_size = self.type_size(elem_ty);
let n_ptr = self.eval_operand(operand)?;
@ -980,6 +993,10 @@ impl<'a, 'tcx> EvalContext<'a, 'tcx> {
}
ConstantIndex { offset, min_length, from_end } => {
// FIXME(solson)
let base = self.force_allocation(base)?;
let (base_ptr, _) = base.to_ptr_and_extra();
let (elem_ty, n) = base.elem_ty_and_len(base_ty);
let elem_size = self.type_size(elem_ty);
assert!(n >= min_length as u64);
@ -995,6 +1012,10 @@ impl<'a, 'tcx> EvalContext<'a, 'tcx> {
}
Subslice { from, to } => {
// FIXME(solson)
let base = self.force_allocation(base)?;
let (base_ptr, _) = base.to_ptr_and_extra();
let (elem_ty, n) = base.elem_ty_and_len(base_ty);
let elem_size = self.type_size(elem_ty);
assert!((from as u64) <= n - (to as u64));