3 fn codegen_field<'a, 'tcx: 'a>(
4 fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
6 layout: TyLayout<'tcx>,
8 ) -> (Value, TyLayout<'tcx>) {
9 let field_offset = layout.fields.offset(field.index());
10 let field_ty = layout.field(&*fx, field.index());
11 if field_offset.bytes() > 0 {
13 fx.bcx.ins().iadd_imm(base, field_offset.bytes() as i64),
21 fn scalar_pair_calculate_b_offset(tcx: TyCtxt<'_>, a_scalar: &Scalar, b_scalar: &Scalar) -> i32 {
22 let b_offset = a_scalar.value.size(&tcx).align_to(b_scalar.value.align(&tcx).abi);
23 b_offset.bytes().try_into().unwrap()
27 #[derive(Debug, Copy, Clone)]
28 pub struct CValue<'tcx>(CValueInner, TyLayout<'tcx>);
30 #[derive(Debug, Copy, Clone)]
34 ByValPair(Value, Value),
37 impl<'tcx> CValue<'tcx> {
38 pub fn by_ref(value: Value, layout: TyLayout<'tcx>) -> CValue<'tcx> {
39 CValue(CValueInner::ByRef(value), layout)
42 pub fn by_val(value: Value, layout: TyLayout<'tcx>) -> CValue<'tcx> {
43 CValue(CValueInner::ByVal(value), layout)
46 pub fn by_val_pair(value: Value, extra: Value, layout: TyLayout<'tcx>) -> CValue<'tcx> {
47 CValue(CValueInner::ByValPair(value, extra), layout)
50 pub fn layout(&self) -> TyLayout<'tcx> {
54 pub fn force_stack<'a>(self, fx: &mut FunctionCx<'a, 'tcx, impl Backend>) -> Value
60 CValueInner::ByRef(value) => value,
61 CValueInner::ByVal(_) | CValueInner::ByValPair(_, _) => {
62 let cplace = CPlace::new_stack_slot(fx, layout.ty);
63 cplace.write_cvalue(fx, self);
69 /// Load a value with layout.abi of scalar
70 pub fn load_scalar<'a>(self, fx: &mut FunctionCx<'a, 'tcx, impl Backend>) -> Value
76 CValueInner::ByRef(addr) => {
77 let scalar = match layout.abi {
78 layout::Abi::Scalar(ref scalar) => scalar.clone(),
81 let clif_ty = scalar_to_clif_type(fx.tcx, scalar);
82 fx.bcx.ins().load(clif_ty, MemFlags::new(), addr, 0)
84 CValueInner::ByVal(value) => value,
85 CValueInner::ByValPair(_, _) => bug!("Please use load_scalar_pair for ByValPair"),
89 /// Load a value pair with layout.abi of scalar pair
90 pub fn load_scalar_pair<'a>(self, fx: &mut FunctionCx<'a, 'tcx, impl Backend>) -> (Value, Value)
96 CValueInner::ByRef(addr) => {
97 let (a_scalar, b_scalar) = match &layout.abi {
98 layout::Abi::ScalarPair(a, b) => (a, b),
101 let b_offset = scalar_pair_calculate_b_offset(fx.tcx, a_scalar, b_scalar);
102 let clif_ty1 = scalar_to_clif_type(fx.tcx, a_scalar.clone());
103 let clif_ty2 = scalar_to_clif_type(fx.tcx, b_scalar.clone());
104 let val1 = fx.bcx.ins().load(clif_ty1, MemFlags::new(), addr, 0);
105 let val2 = fx.bcx.ins().load(
113 CValueInner::ByVal(_) => bug!("Please use load_scalar for ByVal"),
114 CValueInner::ByValPair(val1, val2) => (val1, val2),
118 pub fn value_field<'a>(
120 fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
127 let base = match self.0 {
128 CValueInner::ByRef(addr) => addr,
129 _ => bug!("place_field for {:?}", self),
132 let (field_ptr, field_layout) = codegen_field(fx, base, layout, field);
133 CValue::by_ref(field_ptr, field_layout)
136 pub fn unsize_value<'a>(self, fx: &mut FunctionCx<'a, 'tcx, impl Backend>, dest: CPlace<'tcx>) {
137 crate::unsize::coerce_unsized_into(fx, self, dest);
140 pub fn const_val<'a>(
141 fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
148 let clif_ty = fx.clif_type(ty).unwrap();
149 let layout = fx.layout_of(ty);
150 CValue::by_val(fx.bcx.ins().iconst(clif_ty, const_val), layout)
153 pub fn unchecked_cast_to(self, layout: TyLayout<'tcx>) -> Self {
154 CValue(self.0, layout)
158 /// A place where you can write a value to or read a value from
159 #[derive(Debug, Copy, Clone)]
160 pub enum CPlace<'tcx> {
161 Var(Local, TyLayout<'tcx>),
162 Addr(Value, Option<Value>, TyLayout<'tcx>),
163 Stack(StackSlot, TyLayout<'tcx>),
164 NoPlace(TyLayout<'tcx>),
167 impl<'a, 'tcx: 'a> CPlace<'tcx> {
168 pub fn layout(&self) -> TyLayout<'tcx> {
170 CPlace::Var(_, layout)
171 | CPlace::Addr(_, _, layout)
172 | CPlace::Stack(_, layout)
173 | CPlace::NoPlace(layout) => layout,
177 pub fn no_place(layout: TyLayout<'tcx>) -> CPlace<'tcx> {
178 CPlace::NoPlace(layout)
181 pub fn new_stack_slot(
182 fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
185 let layout = fx.layout_of(ty);
186 assert!(!layout.is_unsized());
187 if layout.size.bytes() == 0 {
188 return CPlace::NoPlace(layout);
191 let stack_slot = fx.bcx.create_stack_slot(StackSlotData {
192 kind: StackSlotKind::ExplicitSlot,
193 size: layout.size.bytes() as u32,
196 CPlace::Stack(stack_slot, layout)
200 fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
202 layout: TyLayout<'tcx>,
205 .declare_var(mir_var(local), fx.clif_type(layout.ty).unwrap());
206 CPlace::Var(local, layout)
209 pub fn for_addr(addr: Value, layout: TyLayout<'tcx>) -> CPlace<'tcx> {
210 CPlace::Addr(addr, None, layout)
213 pub fn for_addr_with_extra(addr: Value, extra: Value, layout: TyLayout<'tcx>) -> CPlace<'tcx> {
214 CPlace::Addr(addr, Some(extra), layout)
217 pub fn to_cvalue(self, fx: &mut FunctionCx<'a, 'tcx, impl Backend>) -> CValue<'tcx> {
219 CPlace::Var(var, layout) => CValue::by_val(fx.bcx.use_var(mir_var(var)), layout),
220 CPlace::Addr(addr, extra, layout) => {
221 assert!(extra.is_none(), "unsized values are not yet supported");
222 CValue::by_ref(addr, layout)
224 CPlace::Stack(stack_slot, layout) => CValue::by_ref(
225 fx.bcx.ins().stack_addr(fx.pointer_type, stack_slot, 0),
228 CPlace::NoPlace(layout) => CValue::by_ref(
231 .iconst(fx.pointer_type, fx.pointer_type.bytes() as i64),
237 pub fn to_addr(self, fx: &mut FunctionCx<'a, 'tcx, impl Backend>) -> Value {
238 match self.to_addr_maybe_unsized(fx) {
239 (addr, None) => addr,
240 (_, Some(_)) => bug!("Expected sized cplace, found {:?}", self),
244 pub fn to_addr_maybe_unsized(
246 fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
247 ) -> (Value, Option<Value>) {
249 CPlace::Addr(addr, extra, _layout) => (addr, extra),
250 CPlace::Stack(stack_slot, _layout) => (
251 fx.bcx.ins().stack_addr(fx.pointer_type, stack_slot, 0),
254 CPlace::NoPlace(_) => (fx.bcx.ins().iconst(fx.pointer_type, 45), None),
255 CPlace::Var(_, _) => bug!("Expected CPlace::Addr, found CPlace::Var"),
259 pub fn write_cvalue(self, fx: &mut FunctionCx<'a, 'tcx, impl Backend>, from: CValue<'tcx>) {
260 use rustc::hir::Mutability::*;
262 let from_ty = from.layout().ty;
263 let to_ty = self.layout().ty;
265 fn assert_assignable<'a, 'tcx: 'a>(fx: &FunctionCx<'a, 'tcx, impl Backend>, from_ty: Ty<'tcx>, to_ty: Ty<'tcx>) {
266 match (&from_ty.sty, &to_ty.sty) {
267 (ty::Ref(_, t, MutImmutable), ty::Ref(_, u, MutImmutable))
268 | (ty::Ref(_, t, MutMutable), ty::Ref(_, u, MutImmutable))
269 | (ty::Ref(_, t, MutMutable), ty::Ref(_, u, MutMutable)) => {
270 assert_assignable(fx, t, u);
271 // &mut T -> &T is allowed
272 // &'a T -> &'b T is allowed
274 (ty::Ref(_, _, MutImmutable), ty::Ref(_, _, MutMutable)) => {
275 panic!("Cant assign value of type {} to place of type {}", from_ty, to_ty)
277 (ty::FnPtr(_), ty::FnPtr(_)) => {
278 let from_sig = fx.tcx.normalize_erasing_late_bound_regions(
279 ParamEnv::reveal_all(),
280 &from_ty.fn_sig(fx.tcx),
282 let to_sig = fx.tcx.normalize_erasing_late_bound_regions(
283 ParamEnv::reveal_all(),
284 &to_ty.fn_sig(fx.tcx),
288 "Can't write fn ptr with incompatible sig {:?} to place with sig {:?}\n\n{:#?}",
289 from_sig, to_sig, fx,
291 // fn(&T) -> for<'l> fn(&'l T) is allowed
293 (ty::Dynamic(from_traits, _), ty::Dynamic(to_traits, _)) => {
294 let from_traits = fx.tcx.normalize_erasing_late_bound_regions(
295 ParamEnv::reveal_all(),
298 let to_traits = fx.tcx.normalize_erasing_late_bound_regions(
299 ParamEnv::reveal_all(),
303 from_traits, to_traits,
304 "Can't write trait object of incompatible traits {:?} to place with traits {:?}\n\n{:#?}",
305 from_traits, to_traits, fx,
307 // dyn for<'r> Trait<'r> -> dyn Trait<'_> is allowed
313 "Can't write value with incompatible type {:?} to place with type {:?}\n\n{:#?}",
322 assert_assignable(fx, from_ty, to_ty);
324 let (addr, dst_layout) = match self {
325 CPlace::Var(var, _) => {
326 let data = from.load_scalar(fx);
327 fx.bcx.def_var(mir_var(var), data);
330 CPlace::Addr(addr, None, dst_layout) => (addr, dst_layout),
331 CPlace::Stack(stack_slot, dst_layout) => (
332 fx.bcx.ins().stack_addr(fx.pointer_type, stack_slot, 0),
335 CPlace::NoPlace(layout) => {
336 if layout.abi != Abi::Uninhabited {
337 assert_eq!(layout.size.bytes(), 0, "{:?}", layout);
341 CPlace::Addr(_, _, _) => bug!("Can't write value to unsized place {:?}", self),
345 CValueInner::ByVal(val) => {
346 fx.bcx.ins().store(MemFlags::new(), val, addr, 0);
348 CValueInner::ByValPair(value, extra) => {
349 match dst_layout.abi {
350 Abi::ScalarPair(ref a_scalar, ref b_scalar) => {
351 let b_offset = scalar_pair_calculate_b_offset(fx.tcx, a_scalar, b_scalar);
352 fx.bcx.ins().store(MemFlags::new(), value, addr, 0);
361 "Non ScalarPair abi {:?} for ByValPair CValue",
366 CValueInner::ByRef(from_addr) => {
367 let src_layout = from.1;
368 let size = dst_layout.size.bytes();
369 let src_align = src_layout.align.abi.bytes() as u8;
370 let dst_align = dst_layout.align.abi.bytes() as u8;
371 fx.bcx.emit_small_memcpy(
372 fx.module.target_config(),
385 fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
388 let layout = self.layout();
389 let (base, extra) = self.to_addr_maybe_unsized(fx);
391 let (field_ptr, field_layout) = codegen_field(fx, base, layout, field);
392 let extra = if field_layout.is_unsized() {
393 assert!(extra.is_some());
398 CPlace::Addr(field_ptr, extra, field_layout)
403 fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
406 let (elem_layout, addr) = match self.layout().ty.sty {
407 ty::Array(elem_ty, _) => (fx.layout_of(elem_ty), self.to_addr(fx)),
408 ty::Slice(elem_ty) => (fx.layout_of(elem_ty), self.to_addr_maybe_unsized(fx).0),
409 _ => bug!("place_index({:?})", self.layout().ty),
415 .imul_imm(index, elem_layout.size.bytes() as i64);
417 CPlace::Addr(fx.bcx.ins().iadd(addr, offset), None, elem_layout)
420 pub fn place_deref(self, fx: &mut FunctionCx<'a, 'tcx, impl Backend>) -> CPlace<'tcx> {
421 let inner_layout = fx.layout_of(self.layout().ty.builtin_deref(true).unwrap().ty);
422 if !inner_layout.is_unsized() {
423 CPlace::Addr(self.to_cvalue(fx).load_scalar(fx), None, inner_layout)
425 let (addr, extra) = self.to_cvalue(fx).load_scalar_pair(fx);
426 CPlace::Addr(addr, Some(extra), inner_layout)
430 pub fn write_place_ref(self, fx: &mut FunctionCx<'a, 'tcx, impl Backend>, dest: CPlace<'tcx>) {
431 if !self.layout().is_unsized() {
432 let ptr = CValue::by_val(self.to_addr(fx), dest.layout());
433 dest.write_cvalue(fx, ptr);
435 let (value, extra) = self.to_addr_maybe_unsized(fx);
436 let ptr = CValue::by_val_pair(value, extra.expect("unsized type without metadata"), dest.layout());
437 dest.write_cvalue(fx, ptr);
441 pub fn unchecked_cast_to(self, layout: TyLayout<'tcx>) -> Self {
442 assert!(!self.layout().is_unsized());
444 CPlace::Var(var, _) => CPlace::Var(var, layout),
445 CPlace::Addr(addr, extra, _) => CPlace::Addr(addr, extra, layout),
446 CPlace::Stack(stack_slot, _) => CPlace::Stack(stack_slot, layout),
447 CPlace::NoPlace(_) => {
448 assert!(layout.size.bytes() == 0);
449 CPlace::NoPlace(layout)
454 pub fn downcast_variant(
456 fx: &FunctionCx<'a, 'tcx, impl Backend>,
459 let layout = self.layout().for_variant(fx, variant);
460 self.unchecked_cast_to(layout)