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use llvm::ValueRef;
use rustc::ty::{self, layout, Ty, TypeFoldable};
use rustc::mir;
use rustc::mir::tcx::LvalueTy;
use rustc_data_structures::indexed_vec::Idx;
use adt;
use builder::Builder;
use common::{self, CrateContext, C_uint};
use consts;
use machine;
use type_of;
use type_::Type;
use value::Value;
use glue;
use std::ptr;
use std::ops;
use super::{MirContext, LocalRef};
use super::operand::OperandValue;
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
pub enum Alignment {
Packed,
AbiAligned,
}
impl ops::BitOr for Alignment {
type Output = Self;
fn bitor(self, rhs: Self) -> Self {
match (self, rhs) {
(Alignment::Packed, _) => Alignment::Packed,
(Alignment::AbiAligned, a) => a,
}
}
}
impl Alignment {
pub fn from_packed(packed: bool) -> Self {
if packed {
Alignment::Packed
} else {
Alignment::AbiAligned
}
}
pub fn to_align(self) -> Option<u32> {
match self {
Alignment::Packed => Some(1),
Alignment::AbiAligned => None,
}
}
pub fn min_with(self, align: u32) -> Option<u32> {
match self {
Alignment::Packed => Some(1),
Alignment::AbiAligned => Some(align),
}
}
}
#[derive(Copy, Clone, Debug)]
pub struct LvalueRef<'tcx> {
pub llval: ValueRef,
pub llextra: ValueRef,
pub ty: LvalueTy<'tcx>,
pub alignment: Alignment,
}
impl<'a, 'tcx> LvalueRef<'tcx> {
pub fn new_sized(llval: ValueRef, lvalue_ty: LvalueTy<'tcx>,
alignment: Alignment) -> LvalueRef<'tcx> {
LvalueRef { llval: llval, llextra: ptr::null_mut(), ty: lvalue_ty, alignment: alignment }
}
pub fn new_sized_ty(llval: ValueRef, ty: Ty<'tcx>, alignment: Alignment) -> LvalueRef<'tcx> {
LvalueRef::new_sized(llval, LvalueTy::from_ty(ty), alignment)
}
pub fn new_unsized_ty(llval: ValueRef, llextra: ValueRef, ty: Ty<'tcx>, alignment: Alignment)
-> LvalueRef<'tcx> {
LvalueRef {
llval: llval,
llextra: llextra,
ty: LvalueTy::from_ty(ty),
alignment: alignment,
}
}
pub fn alloca(bcx: &Builder<'a, 'tcx>, ty: Ty<'tcx>, name: &str) -> LvalueRef<'tcx> {
debug!("alloca({:?}: {:?})", name, ty);
let tmp = bcx.alloca(type_of::type_of(bcx.ccx, ty), name);
assert!(!ty.has_param_types());
Self::new_sized_ty(tmp, ty, Alignment::AbiAligned)
}
pub fn len(&self, ccx: &CrateContext<'a, 'tcx>) -> ValueRef {
let ty = self.ty.to_ty(ccx.tcx());
match ty.sty {
ty::TyArray(_, n) => common::C_uint(ccx, n),
ty::TySlice(_) | ty::TyStr => {
assert!(self.llextra != ptr::null_mut());
self.llextra
}
_ => bug!("unexpected type `{}` in LvalueRef::len", ty)
}
}
pub fn has_extra(&self) -> bool {
!self.llextra.is_null()
}
fn struct_field_ptr(
self,
bcx: &Builder<'a, 'tcx>,
st: &layout::Struct,
fields: &Vec<Ty<'tcx>>,
ix: usize,
needs_cast: bool
) -> (ValueRef, Alignment) {
let fty = fields[ix];
let ccx = bcx.ccx;
let alignment = self.alignment | Alignment::from_packed(st.packed);
let ptr_val = if needs_cast {
let fields = st.field_index_by_increasing_offset().map(|i| {
type_of::in_memory_type_of(ccx, fields[i])
}).collect::<Vec<_>>();
let real_ty = Type::struct_(ccx, &fields[..], st.packed);
bcx.pointercast(self.llval, real_ty.ptr_to())
} else {
self.llval
};
if st.offsets[ix] == layout::Size::from_bytes(0) || st.packed ||
bcx.ccx.shared().type_is_sized(fty) {
return (bcx.struct_gep(ptr_val, st.memory_index[ix] as usize), alignment);
}
match fty.sty {
ty::TySlice(..) | ty::TyStr => {
return (bcx.struct_gep(ptr_val, st.memory_index[ix] as usize), alignment);
}
_ => ()
}
if !self.has_extra() {
debug!("Unsized field `{}`, of `{:?}` has no metadata for adjustment",
ix, Value(ptr_val));
return (bcx.struct_gep(ptr_val, ix), alignment);
}
let meta = self.llextra;
let offset = st.offsets[ix].bytes();
let unaligned_offset = C_uint(bcx.ccx, offset);
let (_, align) = glue::size_and_align_of_dst(bcx, fty, meta);
let align_sub_1 = bcx.sub(align, C_uint(bcx.ccx, 1u64));
let offset = bcx.and(bcx.add(unaligned_offset, align_sub_1),
bcx.neg(align));
debug!("struct_field_ptr: DST field offset: {:?}", Value(offset));
let byte_ptr = bcx.pointercast(ptr_val, Type::i8p(bcx.ccx));
let byte_ptr = bcx.gep(byte_ptr, &[offset]);
let ll_fty = type_of::in_memory_type_of(bcx.ccx, fty);
debug!("struct_field_ptr: Field type is {:?}", ll_fty);
(bcx.pointercast(byte_ptr, ll_fty.ptr_to()), alignment)
}
pub fn trans_field_ptr(self, bcx: &Builder<'a, 'tcx>, ix: usize) -> (ValueRef, Alignment) {
let discr = match self.ty {
LvalueTy::Ty { .. } => 0,
LvalueTy::Downcast { variant_index, .. } => variant_index,
};
let t = self.ty.to_ty(bcx.tcx());
let l = bcx.ccx.layout_of(t);
match *l {
layout::Univariant { ref variant, .. } => {
assert_eq!(discr, 0);
self.struct_field_ptr(bcx, &variant,
&adt::compute_fields(bcx.ccx, t, 0, false), ix, false)
}
layout::Vector { count, .. } => {
assert_eq!(discr, 0);
assert!((ix as u64) < count);
(bcx.struct_gep(self.llval, ix), self.alignment)
}
layout::General { discr: d, ref variants, .. } => {
let mut fields = adt::compute_fields(bcx.ccx, t, discr, false);
fields.insert(0, d.to_ty(&bcx.tcx(), false));
self.struct_field_ptr(bcx, &variants[discr], &fields, ix + 1, true)
}
layout::UntaggedUnion { ref variants } => {
let fields = adt::compute_fields(bcx.ccx, t, 0, false);
let ty = type_of::in_memory_type_of(bcx.ccx, fields[ix]);
(bcx.pointercast(self.llval, ty.ptr_to()),
self.alignment | Alignment::from_packed(variants.packed))
}
layout::RawNullablePointer { nndiscr, .. } |
layout::StructWrappedNullablePointer { nndiscr, .. } if discr as u64 != nndiscr => {
let nullfields = adt::compute_fields(bcx.ccx, t, (1-nndiscr) as usize, false);
let ty = type_of::type_of(bcx.ccx, nullfields[ix]);
assert_eq!(machine::llsize_of_alloc(bcx.ccx, ty), 0);
(bcx.pointercast(self.llval, ty.ptr_to()), Alignment::Packed)
}
layout::RawNullablePointer { nndiscr, .. } => {
let nnty = adt::compute_fields(bcx.ccx, t, nndiscr as usize, false)[0];
assert_eq!(ix, 0);
assert_eq!(discr as u64, nndiscr);
let ty = type_of::type_of(bcx.ccx, nnty);
(bcx.pointercast(self.llval, ty.ptr_to()), self.alignment)
}
layout::StructWrappedNullablePointer { ref nonnull, nndiscr, .. } => {
assert_eq!(discr as u64, nndiscr);
self.struct_field_ptr(bcx, &nonnull,
&adt::compute_fields(bcx.ccx, t, discr, false), ix, false)
}
_ => bug!("element access in type without elements: {} represented as {:#?}", t, l)
}
}
}
impl<'a, 'tcx> MirContext<'a, 'tcx> {
pub fn trans_lvalue(&mut self,
bcx: &Builder<'a, 'tcx>,
lvalue: &mir::Lvalue<'tcx>)
-> LvalueRef<'tcx> {
debug!("trans_lvalue(lvalue={:?})", lvalue);
let ccx = bcx.ccx;
let tcx = ccx.tcx();
if let mir::Lvalue::Local(index) = *lvalue {
match self.locals[index] {
LocalRef::Lvalue(lvalue) => {
return lvalue;
}
LocalRef::Operand(..) => {
bug!("using operand local {:?} as lvalue", lvalue);
}
}
}
let result = match *lvalue {
mir::Lvalue::Local(_) => bug!(),
mir::Lvalue::Static(box mir::Static { def_id, ty }) => {
LvalueRef::new_sized(consts::get_static(ccx, def_id),
LvalueTy::from_ty(self.monomorphize(&ty)),
Alignment::AbiAligned)
},
mir::Lvalue::Projection(box mir::Projection {
ref base,
elem: mir::ProjectionElem::Deref
}) => {
let ptr = self.trans_consume(bcx, base);
let projected_ty = LvalueTy::from_ty(ptr.ty)
.projection_ty(tcx, &mir::ProjectionElem::Deref);
let projected_ty = self.monomorphize(&projected_ty);
let (llptr, llextra) = match ptr.val {
OperandValue::Immediate(llptr) => (llptr, ptr::null_mut()),
OperandValue::Pair(llptr, llextra) => (llptr, llextra),
OperandValue::Ref(..) => bug!("Deref of by-Ref type {:?}", ptr.ty)
};
LvalueRef {
llval: llptr,
llextra: llextra,
ty: projected_ty,
alignment: Alignment::AbiAligned,
}
}
mir::Lvalue::Projection(ref projection) => {
let tr_base = self.trans_lvalue(bcx, &projection.base);
let projected_ty = tr_base.ty.projection_ty(tcx, &projection.elem);
let projected_ty = self.monomorphize(&projected_ty);
let align = tr_base.alignment;
let project_index = |llindex| {
let element = if let ty::TySlice(_) = tr_base.ty.to_ty(tcx).sty {
bcx.inbounds_gep(tr_base.llval, &[llindex])
} else {
let zero = common::C_uint(bcx.ccx, 0u64);
bcx.inbounds_gep(tr_base.llval, &[zero, llindex])
};
(element, align)
};
let ((llprojected, align), llextra) = match projection.elem {
mir::ProjectionElem::Deref => bug!(),
mir::ProjectionElem::Field(ref field, _) => {
let llextra = if self.ccx.shared().type_is_sized(projected_ty.to_ty(tcx)) {
ptr::null_mut()
} else {
tr_base.llextra
};
(tr_base.trans_field_ptr(bcx, field.index()), llextra)
}
mir::ProjectionElem::Index(ref index) => {
let index = self.trans_operand(bcx, index);
(project_index(self.prepare_index(bcx, index.immediate())), ptr::null_mut())
}
mir::ProjectionElem::ConstantIndex { offset,
from_end: false,
min_length: _ } => {
let lloffset = C_uint(bcx.ccx, offset);
(project_index(lloffset), ptr::null_mut())
}
mir::ProjectionElem::ConstantIndex { offset,
from_end: true,
min_length: _ } => {
let lloffset = C_uint(bcx.ccx, offset);
let lllen = tr_base.len(bcx.ccx);
let llindex = bcx.sub(lllen, lloffset);
(project_index(llindex), ptr::null_mut())
}
mir::ProjectionElem::Subslice { from, to } => {
let llindex = C_uint(bcx.ccx, from);
let (llbase, align) = project_index(llindex);
let base_ty = tr_base.ty.to_ty(bcx.tcx());
match base_ty.sty {
ty::TyArray(..) => {
let base_ty = self.monomorphized_lvalue_ty(lvalue);
let llbasety = type_of::type_of(bcx.ccx, base_ty).ptr_to();
let llbase = bcx.pointercast(llbase, llbasety);
((llbase, align), ptr::null_mut())
}
ty::TySlice(..) => {
assert!(tr_base.llextra != ptr::null_mut());
let lllen = bcx.sub(tr_base.llextra,
C_uint(bcx.ccx, from+to));
((llbase, align), lllen)
}
_ => bug!("unexpected type {:?} in Subslice", base_ty)
}
}
mir::ProjectionElem::Downcast(..) => {
((tr_base.llval, align), tr_base.llextra)
}
};
LvalueRef {
llval: llprojected,
llextra: llextra,
ty: projected_ty,
alignment: align,
}
}
};
debug!("trans_lvalue(lvalue={:?}) => {:?}", lvalue, result);
result
}
fn prepare_index(&mut self, bcx: &Builder<'a, 'tcx>, llindex: ValueRef) -> ValueRef {
let index_size = machine::llbitsize_of_real(bcx.ccx, common::val_ty(llindex));
let int_size = machine::llbitsize_of_real(bcx.ccx, bcx.ccx.int_type());
if index_size < int_size {
bcx.zext(llindex, bcx.ccx.int_type())
} else if index_size > int_size {
bcx.trunc(llindex, bcx.ccx.int_type())
} else {
llindex
}
}
pub fn monomorphized_lvalue_ty(&self, lvalue: &mir::Lvalue<'tcx>) -> Ty<'tcx> {
let tcx = self.ccx.tcx();
let lvalue_ty = lvalue.ty(&self.mir, tcx);
self.monomorphize(&lvalue_ty.to_ty(tcx))
}
}