1 //! Definition of [`CValue`] and [`CPlace`]
5 use cranelift_codegen::entity::EntityRef;
6 use cranelift_codegen::ir::immediates::Offset32;
8 fn codegen_field<'tcx>(
9 fx: &mut FunctionCx<'_, 'tcx, impl Module>,
12 layout: TyAndLayout<'tcx>,
14 ) -> (Pointer, TyAndLayout<'tcx>) {
15 let field_offset = layout.fields.offset(field.index());
16 let field_layout = layout.field(&*fx, field.index());
18 let simple = |fx: &mut FunctionCx<'_, '_, _>| {
20 base.offset_i64(fx, i64::try_from(field_offset.bytes()).unwrap()),
25 if let Some(extra) = extra {
26 if !field_layout.is_unsized() {
29 match field_layout.ty.kind() {
30 ty::Slice(..) | ty::Str | ty::Foreign(..) => simple(fx),
31 ty::Adt(def, _) if def.repr.packed() => {
32 assert_eq!(layout.align.abi.bytes(), 1);
36 // We have to align the offset for DST's
37 let unaligned_offset = field_offset.bytes();
38 let (_, unsized_align) =
39 crate::unsize::size_and_align_of_dst(fx, field_layout, extra);
41 let one = fx.bcx.ins().iconst(pointer_ty(fx.tcx), 1);
42 let align_sub_1 = fx.bcx.ins().isub(unsized_align, one);
43 let and_lhs = fx.bcx.ins().iadd_imm(align_sub_1, unaligned_offset as i64);
44 let zero = fx.bcx.ins().iconst(pointer_ty(fx.tcx), 0);
45 let and_rhs = fx.bcx.ins().isub(zero, unsized_align);
46 let offset = fx.bcx.ins().band(and_lhs, and_rhs);
48 (base.offset_value(fx, offset), field_layout)
56 fn scalar_pair_calculate_b_offset(
61 let b_offset = a_scalar
64 .align_to(b_scalar.value.align(&tcx).abi);
65 Offset32::new(b_offset.bytes().try_into().unwrap())
69 #[derive(Debug, Copy, Clone)]
70 pub(crate) struct CValue<'tcx>(CValueInner, TyAndLayout<'tcx>);
72 #[derive(Debug, Copy, Clone)]
74 ByRef(Pointer, Option<Value>),
76 ByValPair(Value, Value),
79 impl<'tcx> CValue<'tcx> {
80 pub(crate) fn by_ref(ptr: Pointer, layout: TyAndLayout<'tcx>) -> CValue<'tcx> {
81 CValue(CValueInner::ByRef(ptr, None), layout)
84 pub(crate) fn by_ref_unsized(
87 layout: TyAndLayout<'tcx>,
89 CValue(CValueInner::ByRef(ptr, Some(meta)), layout)
92 pub(crate) fn by_val(value: Value, layout: TyAndLayout<'tcx>) -> CValue<'tcx> {
93 CValue(CValueInner::ByVal(value), layout)
96 pub(crate) fn by_val_pair(
99 layout: TyAndLayout<'tcx>,
101 CValue(CValueInner::ByValPair(value, extra), layout)
104 pub(crate) fn layout(&self) -> TyAndLayout<'tcx> {
109 pub(crate) fn force_stack(
111 fx: &mut FunctionCx<'_, 'tcx, impl Module>,
112 ) -> (Pointer, Option<Value>) {
115 CValueInner::ByRef(ptr, meta) => (ptr, meta),
116 CValueInner::ByVal(_) | CValueInner::ByValPair(_, _) => {
117 let cplace = CPlace::new_stack_slot(fx, layout);
118 cplace.write_cvalue(fx, self);
119 (cplace.to_ptr(), None)
124 pub(crate) fn try_to_ptr(self) -> Option<(Pointer, Option<Value>)> {
126 CValueInner::ByRef(ptr, meta) => Some((ptr, meta)),
127 CValueInner::ByVal(_) | CValueInner::ByValPair(_, _) => None,
131 /// Load a value with layout.abi of scalar
132 pub(crate) fn load_scalar(self, fx: &mut FunctionCx<'_, 'tcx, impl Module>) -> Value {
135 CValueInner::ByRef(ptr, None) => {
136 let clif_ty = match layout.abi {
137 Abi::Scalar(ref scalar) => scalar_to_clif_type(fx.tcx, scalar.clone()),
138 Abi::Vector { ref element, count } => {
139 scalar_to_clif_type(fx.tcx, element.clone())
140 .by(u16::try_from(count).unwrap())
143 _ => unreachable!("{:?}", layout.ty),
145 let mut flags = MemFlags::new();
147 ptr.load(fx, clif_ty, flags)
149 CValueInner::ByVal(value) => value,
150 CValueInner::ByRef(_, Some(_)) => bug!("load_scalar for unsized value not allowed"),
151 CValueInner::ByValPair(_, _) => bug!("Please use load_scalar_pair for ByValPair"),
155 /// Load a value pair with layout.abi of scalar pair
156 pub(crate) fn load_scalar_pair(
158 fx: &mut FunctionCx<'_, 'tcx, impl Module>,
159 ) -> (Value, Value) {
162 CValueInner::ByRef(ptr, None) => {
163 let (a_scalar, b_scalar) = match &layout.abi {
164 Abi::ScalarPair(a, b) => (a, b),
165 _ => unreachable!("load_scalar_pair({:?})", self),
167 let b_offset = scalar_pair_calculate_b_offset(fx.tcx, a_scalar, b_scalar);
168 let clif_ty1 = scalar_to_clif_type(fx.tcx, a_scalar.clone());
169 let clif_ty2 = scalar_to_clif_type(fx.tcx, b_scalar.clone());
170 let mut flags = MemFlags::new();
172 let val1 = ptr.load(fx, clif_ty1, flags);
173 let val2 = ptr.offset(fx, b_offset).load(fx, clif_ty2, flags);
176 CValueInner::ByRef(_, Some(_)) => {
177 bug!("load_scalar_pair for unsized value not allowed")
179 CValueInner::ByVal(_) => bug!("Please use load_scalar for ByVal"),
180 CValueInner::ByValPair(val1, val2) => (val1, val2),
184 pub(crate) fn value_field(
186 fx: &mut FunctionCx<'_, 'tcx, impl Module>,
191 CValueInner::ByVal(val) => match layout.abi {
192 Abi::Vector { element: _, count } => {
193 let count = u8::try_from(count).expect("SIMD type with more than 255 lanes???");
194 let field = u8::try_from(field.index()).unwrap();
195 assert!(field < count);
196 let lane = fx.bcx.ins().extractlane(val, field);
197 let field_layout = layout.field(&*fx, usize::from(field));
198 CValue::by_val(lane, field_layout)
200 _ => unreachable!("value_field for ByVal with abi {:?}", layout.abi),
202 CValueInner::ByValPair(val1, val2) => match layout.abi {
203 Abi::ScalarPair(_, _) => {
204 let val = match field.as_u32() {
207 _ => bug!("field should be 0 or 1"),
209 let field_layout = layout.field(&*fx, usize::from(field));
210 CValue::by_val(val, field_layout)
212 _ => unreachable!("value_field for ByValPair with abi {:?}", layout.abi),
214 CValueInner::ByRef(ptr, None) => {
215 let (field_ptr, field_layout) = codegen_field(fx, ptr, None, layout, field);
216 CValue::by_ref(field_ptr, field_layout)
218 CValueInner::ByRef(_, Some(_)) => todo!(),
222 pub(crate) fn unsize_value(
224 fx: &mut FunctionCx<'_, 'tcx, impl Module>,
227 crate::unsize::coerce_unsized_into(fx, self, dest);
230 /// If `ty` is signed, `const_val` must already be sign extended.
231 pub(crate) fn const_val(
232 fx: &mut FunctionCx<'_, 'tcx, impl Module>,
233 layout: TyAndLayout<'tcx>,
234 const_val: ty::ScalarInt,
236 assert_eq!(const_val.size(), layout.size);
237 use cranelift_codegen::ir::immediates::{Ieee32, Ieee64};
239 let clif_ty = fx.clif_type(layout.ty).unwrap();
241 if let ty::Bool = layout.ty.kind() {
243 const_val == ty::ScalarInt::FALSE || const_val == ty::ScalarInt::TRUE,
244 "Invalid bool 0x{:032X}",
249 let val = match layout.ty.kind() {
250 ty::Uint(UintTy::U128) | ty::Int(IntTy::I128) => {
251 let const_val = const_val.to_bits(layout.size).unwrap();
252 let lsb = fx.bcx.ins().iconst(types::I64, const_val as u64 as i64);
256 .iconst(types::I64, (const_val >> 64) as u64 as i64);
257 fx.bcx.ins().iconcat(lsb, msb)
259 ty::Bool | ty::Char | ty::Uint(_) | ty::Int(_) | ty::Ref(..)
260 | ty::RawPtr(..) => {
264 .iconst(clif_ty, const_val.to_bits(layout.size).unwrap() as i64)
266 ty::Float(FloatTy::F32) => {
267 fx.bcx.ins().f32const(Ieee32::with_bits(u32::try_from(const_val).unwrap()))
269 ty::Float(FloatTy::F64) => {
270 fx.bcx.ins().f64const(Ieee64::with_bits(u64::try_from(const_val).unwrap()))
273 "CValue::const_val for non bool/char/float/integer/pointer type {:?} is not allowed",
278 CValue::by_val(val, layout)
281 pub(crate) fn cast_pointer_to(self, layout: TyAndLayout<'tcx>) -> Self {
283 self.layout().ty.kind(),
284 ty::Ref(..) | ty::RawPtr(..) | ty::FnPtr(..)
288 ty::Ref(..) | ty::RawPtr(..) | ty::FnPtr(..)
290 assert_eq!(self.layout().abi, layout.abi);
291 CValue(self.0, layout)
295 /// A place where you can write a value to or read a value from
296 #[derive(Debug, Copy, Clone)]
297 pub(crate) struct CPlace<'tcx> {
299 layout: TyAndLayout<'tcx>,
302 #[derive(Debug, Copy, Clone)]
303 pub(crate) enum CPlaceInner {
304 Var(Local, Variable),
305 VarPair(Local, Variable, Variable),
306 VarLane(Local, Variable, u8),
307 Addr(Pointer, Option<Value>),
310 impl<'tcx> CPlace<'tcx> {
311 pub(crate) fn layout(&self) -> TyAndLayout<'tcx> {
315 pub(crate) fn inner(&self) -> &CPlaceInner {
319 pub(crate) fn no_place(layout: TyAndLayout<'tcx>) -> CPlace<'tcx> {
321 inner: CPlaceInner::Addr(Pointer::dangling(layout.align.pref), None),
326 pub(crate) fn new_stack_slot(
327 fx: &mut FunctionCx<'_, 'tcx, impl Module>,
328 layout: TyAndLayout<'tcx>,
330 assert!(!layout.is_unsized());
331 if layout.size.bytes() == 0 {
332 return CPlace::no_place(layout);
335 let stack_slot = fx.bcx.create_stack_slot(StackSlotData {
336 kind: StackSlotKind::ExplicitSlot,
337 size: u32::try_from(layout.size.bytes()).unwrap(),
341 inner: CPlaceInner::Addr(Pointer::stack_slot(stack_slot), None),
346 pub(crate) fn new_var(
347 fx: &mut FunctionCx<'_, 'tcx, impl Module>,
349 layout: TyAndLayout<'tcx>,
351 let var = Variable::with_u32(fx.next_ssa_var);
352 fx.next_ssa_var += 1;
353 fx.bcx.declare_var(var, fx.clif_type(layout.ty).unwrap());
355 inner: CPlaceInner::Var(local, var),
360 pub(crate) fn new_var_pair(
361 fx: &mut FunctionCx<'_, 'tcx, impl Module>,
363 layout: TyAndLayout<'tcx>,
365 let var1 = Variable::with_u32(fx.next_ssa_var);
366 fx.next_ssa_var += 1;
367 let var2 = Variable::with_u32(fx.next_ssa_var);
368 fx.next_ssa_var += 1;
370 let (ty1, ty2) = fx.clif_pair_type(layout.ty).unwrap();
371 fx.bcx.declare_var(var1, ty1);
372 fx.bcx.declare_var(var2, ty2);
374 inner: CPlaceInner::VarPair(local, var1, var2),
379 pub(crate) fn for_ptr(ptr: Pointer, layout: TyAndLayout<'tcx>) -> CPlace<'tcx> {
381 inner: CPlaceInner::Addr(ptr, None),
386 pub(crate) fn for_ptr_with_extra(
389 layout: TyAndLayout<'tcx>,
392 inner: CPlaceInner::Addr(ptr, Some(extra)),
397 pub(crate) fn to_cvalue(self, fx: &mut FunctionCx<'_, 'tcx, impl Module>) -> CValue<'tcx> {
398 let layout = self.layout();
400 CPlaceInner::Var(_local, var) => {
401 let val = fx.bcx.use_var(var);
403 .set_val_label(val, cranelift_codegen::ir::ValueLabel::new(var.index()));
404 CValue::by_val(val, layout)
406 CPlaceInner::VarPair(_local, var1, var2) => {
407 let val1 = fx.bcx.use_var(var1);
409 .set_val_label(val1, cranelift_codegen::ir::ValueLabel::new(var1.index()));
410 let val2 = fx.bcx.use_var(var2);
412 .set_val_label(val2, cranelift_codegen::ir::ValueLabel::new(var2.index()));
413 CValue::by_val_pair(val1, val2, layout)
415 CPlaceInner::VarLane(_local, var, lane) => {
416 let val = fx.bcx.use_var(var);
418 .set_val_label(val, cranelift_codegen::ir::ValueLabel::new(var.index()));
419 let val = fx.bcx.ins().extractlane(val, lane);
420 CValue::by_val(val, layout)
422 CPlaceInner::Addr(ptr, extra) => {
423 if let Some(extra) = extra {
424 CValue::by_ref_unsized(ptr, extra, layout)
426 CValue::by_ref(ptr, layout)
432 pub(crate) fn to_ptr(self) -> Pointer {
433 match self.to_ptr_maybe_unsized() {
435 (_, Some(_)) => bug!("Expected sized cplace, found {:?}", self),
439 pub(crate) fn to_ptr_maybe_unsized(self) -> (Pointer, Option<Value>) {
441 CPlaceInner::Addr(ptr, extra) => (ptr, extra),
442 CPlaceInner::Var(_, _)
443 | CPlaceInner::VarPair(_, _, _)
444 | CPlaceInner::VarLane(_, _, _) => bug!("Expected CPlace::Addr, found {:?}", self),
448 pub(crate) fn write_cvalue(
450 fx: &mut FunctionCx<'_, 'tcx, impl Module>,
453 fn assert_assignable<'tcx>(
454 fx: &FunctionCx<'_, 'tcx, impl Module>,
458 match (from_ty.kind(), to_ty.kind()) {
459 (ty::Ref(_, a, _), ty::Ref(_, b, _))
461 ty::RawPtr(TypeAndMut { ty: a, mutbl: _ }),
462 ty::RawPtr(TypeAndMut { ty: b, mutbl: _ }),
464 assert_assignable(fx, a, b);
466 (ty::FnPtr(_), ty::FnPtr(_)) => {
467 let from_sig = fx.tcx.normalize_erasing_late_bound_regions(
468 ParamEnv::reveal_all(),
469 from_ty.fn_sig(fx.tcx),
471 let to_sig = fx.tcx.normalize_erasing_late_bound_regions(
472 ParamEnv::reveal_all(),
473 to_ty.fn_sig(fx.tcx),
477 "Can't write fn ptr with incompatible sig {:?} to place with sig {:?}\n\n{:#?}",
478 from_sig, to_sig, fx,
480 // fn(&T) -> for<'l> fn(&'l T) is allowed
482 (&ty::Dynamic(from_traits, _), &ty::Dynamic(to_traits, _)) => {
485 .normalize_erasing_late_bound_regions(ParamEnv::reveal_all(), from_traits);
488 .normalize_erasing_late_bound_regions(ParamEnv::reveal_all(), to_traits);
490 from_traits, to_traits,
491 "Can't write trait object of incompatible traits {:?} to place with traits {:?}\n\n{:#?}",
492 from_traits, to_traits, fx,
494 // dyn for<'r> Trait<'r> -> dyn Trait<'_> is allowed
500 "Can't write value with incompatible type {:?} to place with type {:?}\n\n{:#?}",
509 assert_assignable(fx, from.layout().ty, self.layout().ty);
511 self.write_cvalue_maybe_transmute(fx, from, "write_cvalue");
514 pub(crate) fn write_cvalue_transmute(
516 fx: &mut FunctionCx<'_, 'tcx, impl Module>,
519 self.write_cvalue_maybe_transmute(fx, from, "write_cvalue_transmute");
522 fn write_cvalue_maybe_transmute(
524 fx: &mut FunctionCx<'_, 'tcx, impl Module>,
526 #[cfg_attr(not(debug_assertions), allow(unused_variables))] method: &'static str,
528 fn transmute_value<'tcx>(
529 fx: &mut FunctionCx<'_, 'tcx, impl Module>,
534 let src_ty = fx.bcx.func.dfg.value_type(data);
538 "write_cvalue_transmute: {:?} -> {:?}",
542 let data = match (src_ty, dst_ty) {
543 (_, _) if src_ty == dst_ty => data,
545 // This is a `write_cvalue_transmute`.
546 (types::I32, types::F32)
547 | (types::F32, types::I32)
548 | (types::I64, types::F64)
549 | (types::F64, types::I64) => fx.bcx.ins().bitcast(dst_ty, data),
550 _ if src_ty.is_vector() && dst_ty.is_vector() => {
551 fx.bcx.ins().raw_bitcast(dst_ty, data)
553 _ if src_ty.is_vector() || dst_ty.is_vector() => {
554 // FIXME do something more efficient for transmutes between vectors and integers.
555 let stack_slot = fx.bcx.create_stack_slot(StackSlotData {
556 kind: StackSlotKind::ExplicitSlot,
557 size: src_ty.bytes(),
560 let ptr = Pointer::stack_slot(stack_slot);
561 ptr.store(fx, data, MemFlags::trusted());
562 ptr.load(fx, dst_ty, MemFlags::trusted())
564 _ => unreachable!("write_cvalue_transmute: {:?} -> {:?}", src_ty, dst_ty),
567 .set_val_label(data, cranelift_codegen::ir::ValueLabel::new(var.index()));
568 fx.bcx.def_var(var, data);
571 assert_eq!(self.layout().size, from.layout().size);
573 #[cfg(debug_assertions)]
575 use cranelift_codegen::cursor::{Cursor, CursorPosition};
576 let cur_block = match fx.bcx.cursor().position() {
577 CursorPosition::After(block) => block,
581 fx.bcx.func.layout.last_inst(cur_block).unwrap(),
583 "{}: {:?}: {:?} <- {:?}: {:?}",
593 let dst_layout = self.layout();
594 let to_ptr = match self.inner {
595 CPlaceInner::Var(_local, var) => {
596 let data = CValue(from.0, dst_layout).load_scalar(fx);
597 let dst_ty = fx.clif_type(self.layout().ty).unwrap();
598 transmute_value(fx, var, data, dst_ty);
601 CPlaceInner::VarPair(_local, var1, var2) => {
602 let (data1, data2) = CValue(from.0, dst_layout).load_scalar_pair(fx);
603 let (dst_ty1, dst_ty2) = fx.clif_pair_type(self.layout().ty).unwrap();
604 transmute_value(fx, var1, data1, dst_ty1);
605 transmute_value(fx, var2, data2, dst_ty2);
608 CPlaceInner::VarLane(_local, var, lane) => {
609 let data = from.load_scalar(fx);
611 // First get the old vector
612 let vector = fx.bcx.use_var(var);
614 .set_val_label(vector, cranelift_codegen::ir::ValueLabel::new(var.index()));
616 // Next insert the written lane into the vector
617 let vector = fx.bcx.ins().insertlane(vector, data, lane);
619 // Finally write the new vector
621 .set_val_label(vector, cranelift_codegen::ir::ValueLabel::new(var.index()));
622 fx.bcx.def_var(var, vector);
626 CPlaceInner::Addr(ptr, None) => {
627 if dst_layout.size == Size::ZERO || dst_layout.abi == Abi::Uninhabited {
632 CPlaceInner::Addr(_, Some(_)) => bug!("Can't write value to unsized place {:?}", self),
635 let mut flags = MemFlags::new();
637 match from.layout().abi {
638 // FIXME make Abi::Vector work too
640 let val = from.load_scalar(fx);
641 to_ptr.store(fx, val, flags);
644 Abi::ScalarPair(ref a_scalar, ref b_scalar) => {
645 let (value, extra) = from.load_scalar_pair(fx);
646 let b_offset = scalar_pair_calculate_b_offset(fx.tcx, a_scalar, b_scalar);
647 to_ptr.store(fx, value, flags);
648 to_ptr.offset(fx, b_offset).store(fx, extra, flags);
655 CValueInner::ByVal(val) => {
656 to_ptr.store(fx, val, flags);
658 CValueInner::ByValPair(_, _) => {
660 "Non ScalarPair abi {:?} for ByValPair CValue",
664 CValueInner::ByRef(from_ptr, None) => {
665 let from_addr = from_ptr.get_addr(fx);
666 let to_addr = to_ptr.get_addr(fx);
667 let src_layout = from.1;
668 let size = dst_layout.size.bytes();
669 let src_align = src_layout.align.abi.bytes() as u8;
670 let dst_align = dst_layout.align.abi.bytes() as u8;
671 fx.bcx.emit_small_memory_copy(
672 fx.cx.module.target_config(),
681 CValueInner::ByRef(_, Some(_)) => todo!(),
685 pub(crate) fn place_field(
687 fx: &mut FunctionCx<'_, 'tcx, impl Module>,
690 let layout = self.layout();
693 CPlaceInner::Var(local, var) => {
694 if let Abi::Vector { .. } = layout.abi {
696 inner: CPlaceInner::VarLane(local, var, field.as_u32().try_into().unwrap()),
697 layout: layout.field(fx, field.as_u32().try_into().unwrap()),
701 CPlaceInner::VarPair(local, var1, var2) => {
702 let layout = layout.field(&*fx, field.index());
704 match field.as_u32() {
707 inner: CPlaceInner::Var(local, var1),
713 inner: CPlaceInner::Var(local, var2),
717 _ => unreachable!("field should be 0 or 1"),
723 let (base, extra) = self.to_ptr_maybe_unsized();
725 let (field_ptr, field_layout) = codegen_field(fx, base, extra, layout, field);
726 if field_layout.is_unsized() {
727 CPlace::for_ptr_with_extra(field_ptr, extra.unwrap(), field_layout)
729 CPlace::for_ptr(field_ptr, field_layout)
733 pub(crate) fn place_index(
735 fx: &mut FunctionCx<'_, 'tcx, impl Module>,
738 let (elem_layout, ptr) = match self.layout().ty.kind() {
739 ty::Array(elem_ty, _) => (fx.layout_of(elem_ty), self.to_ptr()),
740 ty::Slice(elem_ty) => (fx.layout_of(elem_ty), self.to_ptr_maybe_unsized().0),
741 _ => bug!("place_index({:?})", self.layout().ty),
747 .imul_imm(index, elem_layout.size.bytes() as i64);
749 CPlace::for_ptr(ptr.offset_value(fx, offset), elem_layout)
752 pub(crate) fn place_deref(self, fx: &mut FunctionCx<'_, 'tcx, impl Module>) -> CPlace<'tcx> {
753 let inner_layout = fx.layout_of(self.layout().ty.builtin_deref(true).unwrap().ty);
754 if has_ptr_meta(fx.tcx, inner_layout.ty) {
755 let (addr, extra) = self.to_cvalue(fx).load_scalar_pair(fx);
756 CPlace::for_ptr_with_extra(Pointer::new(addr), extra, inner_layout)
759 Pointer::new(self.to_cvalue(fx).load_scalar(fx)),
765 pub(crate) fn place_ref(
767 fx: &mut FunctionCx<'_, 'tcx, impl Module>,
768 layout: TyAndLayout<'tcx>,
770 if has_ptr_meta(fx.tcx, self.layout().ty) {
771 let (ptr, extra) = self.to_ptr_maybe_unsized();
774 extra.expect("unsized type without metadata"),
778 CValue::by_val(self.to_ptr().get_addr(fx), layout)
782 pub(crate) fn downcast_variant(
784 fx: &FunctionCx<'_, 'tcx, impl Module>,
787 assert!(!self.layout().is_unsized());
788 let layout = self.layout().for_variant(fx, variant);