Files
rust/compiler/rustc_codegen_cranelift/src/value_and_place.rs
lcnr 9cba14b95b use TypingEnv when no infcx is available
the behavior of the type system not only depends on the current
assumptions, but also the currentnphase of the compiler. This is
mostly necessary as we need to decide whether and how to reveal
opaque types. We track this via the `TypingMode`.
2024-11-18 10:38:56 +01:00

1023 lines
40 KiB
Rust

//! Definition of [`CValue`] and [`CPlace`]
use cranelift_codegen::entity::EntityRef;
use cranelift_codegen::ir::immediates::Offset32;
use cranelift_frontend::Variable;
use rustc_middle::ty::FnSig;
use rustc_middle::ty::layout::HasTypingEnv;
use crate::prelude::*;
fn codegen_field<'tcx>(
fx: &mut FunctionCx<'_, '_, 'tcx>,
base: Pointer,
extra: Option<Value>,
layout: TyAndLayout<'tcx>,
field: FieldIdx,
) -> (Pointer, TyAndLayout<'tcx>) {
let field_offset = layout.fields.offset(field.index());
let field_layout = layout.field(&*fx, field.index());
let simple = |fx: &mut FunctionCx<'_, '_, '_>| {
(base.offset_i64(fx, i64::try_from(field_offset.bytes()).unwrap()), field_layout)
};
if field_layout.is_sized() {
return simple(fx);
}
match field_layout.ty.kind() {
ty::Slice(..) | ty::Str => simple(fx),
_ => {
let unaligned_offset = field_offset.bytes();
// Get the alignment of the field
let (_, mut unsized_align) = crate::unsize::size_and_align_of(fx, field_layout, extra);
// For packed types, we need to cap alignment.
if let ty::Adt(def, _) = layout.ty.kind() {
if let Some(packed) = def.repr().pack {
let packed = fx.bcx.ins().iconst(fx.pointer_type, packed.bytes() as i64);
let cmp = fx.bcx.ins().icmp(IntCC::UnsignedLessThan, unsized_align, packed);
unsized_align = fx.bcx.ins().select(cmp, unsized_align, packed);
}
}
// Bump the unaligned offset up to the appropriate alignment
let one = fx.bcx.ins().iconst(fx.pointer_type, 1);
let align_sub_1 = fx.bcx.ins().isub(unsized_align, one);
let and_lhs = fx.bcx.ins().iadd_imm(align_sub_1, unaligned_offset as i64);
let zero = fx.bcx.ins().iconst(fx.pointer_type, 0);
let and_rhs = fx.bcx.ins().isub(zero, unsized_align);
let offset = fx.bcx.ins().band(and_lhs, and_rhs);
(base.offset_value(fx, offset), field_layout)
}
}
}
fn scalar_pair_calculate_b_offset(tcx: TyCtxt<'_>, a_scalar: Scalar, b_scalar: Scalar) -> Offset32 {
let b_offset = a_scalar.size(&tcx).align_to(b_scalar.align(&tcx).abi);
Offset32::new(b_offset.bytes().try_into().unwrap())
}
/// A read-only value
#[derive(Debug, Copy, Clone)]
pub(crate) struct CValue<'tcx>(CValueInner, TyAndLayout<'tcx>);
#[derive(Debug, Copy, Clone)]
enum CValueInner {
ByRef(Pointer, Option<Value>),
ByVal(Value),
ByValPair(Value, Value),
}
impl<'tcx> CValue<'tcx> {
pub(crate) fn by_ref(ptr: Pointer, layout: TyAndLayout<'tcx>) -> CValue<'tcx> {
CValue(CValueInner::ByRef(ptr, None), layout)
}
pub(crate) fn by_ref_unsized(
ptr: Pointer,
meta: Value,
layout: TyAndLayout<'tcx>,
) -> CValue<'tcx> {
CValue(CValueInner::ByRef(ptr, Some(meta)), layout)
}
pub(crate) fn by_val(value: Value, layout: TyAndLayout<'tcx>) -> CValue<'tcx> {
CValue(CValueInner::ByVal(value), layout)
}
pub(crate) fn by_val_pair(
value: Value,
extra: Value,
layout: TyAndLayout<'tcx>,
) -> CValue<'tcx> {
CValue(CValueInner::ByValPair(value, extra), layout)
}
/// Create an instance of a ZST
///
/// The is represented by a dangling pointer of suitable alignment.
pub(crate) fn zst(layout: TyAndLayout<'tcx>) -> CValue<'tcx> {
assert!(layout.is_zst());
CValue::by_ref(crate::Pointer::dangling(layout.align.pref), layout)
}
pub(crate) fn layout(&self) -> TyAndLayout<'tcx> {
self.1
}
// FIXME remove
pub(crate) fn force_stack(self, fx: &mut FunctionCx<'_, '_, 'tcx>) -> (Pointer, Option<Value>) {
let layout = self.1;
match self.0 {
CValueInner::ByRef(ptr, meta) => (ptr, meta),
CValueInner::ByVal(_) | CValueInner::ByValPair(_, _) => {
let cplace = CPlace::new_stack_slot(fx, layout);
cplace.write_cvalue(fx, self);
(cplace.to_ptr(), None)
}
}
}
// FIXME remove
/// Forces the data value of a dyn* value to the stack and returns a pointer to it as well as the
/// vtable pointer.
pub(crate) fn dyn_star_force_data_on_stack(
self,
fx: &mut FunctionCx<'_, '_, 'tcx>,
) -> (Value, Value) {
assert!(self.1.ty.is_dyn_star());
match self.0 {
CValueInner::ByRef(ptr, None) => {
let (a_scalar, b_scalar) = match self.1.backend_repr {
BackendRepr::ScalarPair(a, b) => (a, b),
_ => unreachable!("dyn_star_force_data_on_stack({:?})", self),
};
let b_offset = scalar_pair_calculate_b_offset(fx.tcx, a_scalar, b_scalar);
let clif_ty2 = scalar_to_clif_type(fx.tcx, b_scalar);
let mut flags = MemFlags::new();
flags.set_notrap();
let vtable = ptr.offset(fx, b_offset).load(fx, clif_ty2, flags);
(ptr.get_addr(fx), vtable)
}
CValueInner::ByValPair(data, vtable) => {
let data_ptr = fx.create_stack_slot(
u32::try_from(fx.target_config.pointer_type().bytes()).unwrap(),
u32::try_from(fx.target_config.pointer_type().bytes()).unwrap(),
);
data_ptr.store(fx, data, MemFlags::trusted());
(data_ptr.get_addr(fx), vtable)
}
CValueInner::ByRef(_, Some(_)) | CValueInner::ByVal(_) => {
unreachable!("dyn_star_force_data_on_stack({:?})", self)
}
}
}
pub(crate) fn try_to_ptr(self) -> Option<(Pointer, Option<Value>)> {
match self.0 {
CValueInner::ByRef(ptr, meta) => Some((ptr, meta)),
CValueInner::ByVal(_) | CValueInner::ByValPair(_, _) => None,
}
}
/// Load a value with layout.backend_repr of scalar
#[track_caller]
pub(crate) fn load_scalar(self, fx: &mut FunctionCx<'_, '_, 'tcx>) -> Value {
let layout = self.1;
match self.0 {
CValueInner::ByRef(ptr, None) => {
let clif_ty = match layout.backend_repr {
BackendRepr::Scalar(scalar) => scalar_to_clif_type(fx.tcx, scalar),
BackendRepr::Vector { element, count } => scalar_to_clif_type(fx.tcx, element)
.by(u32::try_from(count).unwrap())
.unwrap(),
_ => unreachable!("{:?}", layout.ty),
};
let mut flags = MemFlags::new();
flags.set_notrap();
ptr.load(fx, clif_ty, flags)
}
CValueInner::ByVal(value) => value,
CValueInner::ByRef(_, Some(_)) => bug!("load_scalar for unsized value not allowed"),
CValueInner::ByValPair(_, _) => bug!("Please use load_scalar_pair for ByValPair"),
}
}
/// Load a value pair with layout.backend_repr of scalar pair
#[track_caller]
pub(crate) fn load_scalar_pair(self, fx: &mut FunctionCx<'_, '_, 'tcx>) -> (Value, Value) {
let layout = self.1;
match self.0 {
CValueInner::ByRef(ptr, None) => {
let (a_scalar, b_scalar) = match layout.backend_repr {
BackendRepr::ScalarPair(a, b) => (a, b),
_ => unreachable!("load_scalar_pair({:?})", self),
};
let b_offset = scalar_pair_calculate_b_offset(fx.tcx, a_scalar, b_scalar);
let clif_ty1 = scalar_to_clif_type(fx.tcx, a_scalar);
let clif_ty2 = scalar_to_clif_type(fx.tcx, b_scalar);
let mut flags = MemFlags::new();
flags.set_notrap();
let val1 = ptr.load(fx, clif_ty1, flags);
let val2 = ptr.offset(fx, b_offset).load(fx, clif_ty2, flags);
(val1, val2)
}
CValueInner::ByRef(_, Some(_)) => {
bug!("load_scalar_pair for unsized value not allowed")
}
CValueInner::ByVal(_) => bug!("Please use load_scalar for ByVal"),
CValueInner::ByValPair(val1, val2) => (val1, val2),
}
}
pub(crate) fn value_field(
self,
fx: &mut FunctionCx<'_, '_, 'tcx>,
field: FieldIdx,
) -> CValue<'tcx> {
let layout = self.1;
match self.0 {
CValueInner::ByVal(_) => unreachable!(),
CValueInner::ByValPair(val1, val2) => match layout.backend_repr {
BackendRepr::ScalarPair(_, _) => {
let val = match field.as_u32() {
0 => val1,
1 => val2,
_ => bug!("field should be 0 or 1"),
};
let field_layout = layout.field(&*fx, usize::from(field));
CValue::by_val(val, field_layout)
}
_ => unreachable!("value_field for ByValPair with abi {:?}", layout.backend_repr),
},
CValueInner::ByRef(ptr, None) => {
let (field_ptr, field_layout) = codegen_field(fx, ptr, None, layout, field);
CValue::by_ref(field_ptr, field_layout)
}
CValueInner::ByRef(_, Some(_)) => todo!(),
}
}
/// Like [`CValue::value_field`] except handling ADTs containing a single array field in a way
/// such that you can access individual lanes.
pub(crate) fn value_lane(
self,
fx: &mut FunctionCx<'_, '_, 'tcx>,
lane_idx: u64,
) -> CValue<'tcx> {
let layout = self.1;
assert!(layout.ty.is_simd());
let (lane_count, lane_ty) = layout.ty.simd_size_and_type(fx.tcx);
let lane_layout = fx.layout_of(lane_ty);
assert!(lane_idx < lane_count);
match self.0 {
CValueInner::ByVal(_) | CValueInner::ByValPair(_, _) => unreachable!(),
CValueInner::ByRef(ptr, None) => {
let field_offset = lane_layout.size * lane_idx;
let field_ptr = ptr.offset_i64(fx, i64::try_from(field_offset.bytes()).unwrap());
CValue::by_ref(field_ptr, lane_layout)
}
CValueInner::ByRef(_, Some(_)) => unreachable!(),
}
}
/// Like [`CValue::value_field`] except using the passed type as lane type instead of the one
/// specified by the vector type.
pub(crate) fn value_typed_lane(
self,
fx: &mut FunctionCx<'_, '_, 'tcx>,
lane_ty: Ty<'tcx>,
lane_idx: u64,
) -> CValue<'tcx> {
let layout = self.1;
assert!(layout.ty.is_simd());
let (orig_lane_count, orig_lane_ty) = layout.ty.simd_size_and_type(fx.tcx);
let lane_layout = fx.layout_of(lane_ty);
assert!(
(lane_idx + 1) * lane_layout.size <= orig_lane_count * fx.layout_of(orig_lane_ty).size
);
match self.0 {
CValueInner::ByVal(_) | CValueInner::ByValPair(_, _) => unreachable!(),
CValueInner::ByRef(ptr, None) => {
let field_offset = lane_layout.size * lane_idx;
let field_ptr = ptr.offset_i64(fx, i64::try_from(field_offset.bytes()).unwrap());
CValue::by_ref(field_ptr, lane_layout)
}
CValueInner::ByRef(_, Some(_)) => unreachable!(),
}
}
/// Like [`CValue::value_lane`] except allowing a dynamically calculated lane index.
pub(crate) fn value_lane_dyn(
self,
fx: &mut FunctionCx<'_, '_, 'tcx>,
lane_idx: Value,
) -> CValue<'tcx> {
let layout = self.1;
assert!(layout.ty.is_simd());
let (_lane_count, lane_ty) = layout.ty.simd_size_and_type(fx.tcx);
let lane_layout = fx.layout_of(lane_ty);
match self.0 {
CValueInner::ByVal(_) | CValueInner::ByValPair(_, _) => unreachable!(),
CValueInner::ByRef(ptr, None) => {
let field_offset = fx.bcx.ins().imul_imm(lane_idx, lane_layout.size.bytes() as i64);
let field_ptr = ptr.offset_value(fx, field_offset);
CValue::by_ref(field_ptr, lane_layout)
}
CValueInner::ByRef(_, Some(_)) => unreachable!(),
}
}
/// If `ty` is signed, `const_val` must already be sign extended.
pub(crate) fn const_val(
fx: &mut FunctionCx<'_, '_, 'tcx>,
layout: TyAndLayout<'tcx>,
const_val: ty::ScalarInt,
) -> CValue<'tcx> {
assert_eq!(const_val.size(), layout.size, "{:#?}: {:?}", const_val, layout);
use cranelift_codegen::ir::immediates::{Ieee32, Ieee64};
let clif_ty = fx.clif_type(layout.ty).unwrap();
let val = match layout.ty.kind() {
ty::Uint(UintTy::U128) | ty::Int(IntTy::I128) => {
let const_val = const_val.to_bits(layout.size);
let lsb = fx.bcx.ins().iconst(types::I64, const_val as u64 as i64);
let msb = fx.bcx.ins().iconst(types::I64, (const_val >> 64) as u64 as i64);
fx.bcx.ins().iconcat(lsb, msb)
}
ty::Bool
| ty::Char
| ty::Uint(_)
| ty::Int(_)
| ty::Ref(..)
| ty::RawPtr(..)
| ty::FnPtr(..) => {
let raw_val = const_val.size().truncate(const_val.to_bits(layout.size));
fx.bcx.ins().iconst(clif_ty, raw_val as i64)
}
ty::Float(FloatTy::F32) => {
fx.bcx.ins().f32const(Ieee32::with_bits(u32::try_from(const_val).unwrap()))
}
ty::Float(FloatTy::F64) => {
fx.bcx.ins().f64const(Ieee64::with_bits(u64::try_from(const_val).unwrap()))
}
_ => panic!(
"CValue::const_val for non bool/char/float/integer/pointer type {:?} is not allowed",
layout.ty
),
};
CValue::by_val(val, layout)
}
pub(crate) fn cast_pointer_to(self, layout: TyAndLayout<'tcx>) -> Self {
assert!(matches!(self.layout().ty.kind(), ty::Ref(..) | ty::RawPtr(..) | ty::FnPtr(..)));
assert!(matches!(layout.ty.kind(), ty::Ref(..) | ty::RawPtr(..) | ty::FnPtr(..)));
assert_eq!(self.layout().backend_repr, layout.backend_repr);
CValue(self.0, layout)
}
}
/// A place where you can write a value to or read a value from
#[derive(Debug, Copy, Clone)]
pub(crate) struct CPlace<'tcx> {
inner: CPlaceInner,
layout: TyAndLayout<'tcx>,
}
#[derive(Debug, Copy, Clone)]
enum CPlaceInner {
Var(Local, Variable),
VarPair(Local, Variable, Variable),
Addr(Pointer, Option<Value>),
}
impl<'tcx> CPlace<'tcx> {
pub(crate) fn layout(&self) -> TyAndLayout<'tcx> {
self.layout
}
pub(crate) fn new_stack_slot(
fx: &mut FunctionCx<'_, '_, 'tcx>,
layout: TyAndLayout<'tcx>,
) -> CPlace<'tcx> {
assert!(layout.is_sized());
if layout.size.bytes() == 0 {
return CPlace {
inner: CPlaceInner::Addr(Pointer::dangling(layout.align.pref), None),
layout,
};
}
if layout.size.bytes() >= u64::from(u32::MAX - 16) {
fx.tcx
.dcx()
.fatal(format!("values of type {} are too big to store on the stack", layout.ty));
}
let stack_slot = fx.create_stack_slot(
u32::try_from(layout.size.bytes()).unwrap(),
u32::try_from(layout.align.pref.bytes()).unwrap(),
);
CPlace { inner: CPlaceInner::Addr(stack_slot, None), layout }
}
pub(crate) fn new_var(
fx: &mut FunctionCx<'_, '_, 'tcx>,
local: Local,
layout: TyAndLayout<'tcx>,
) -> CPlace<'tcx> {
let var = Variable::from_u32(fx.next_ssa_var);
fx.next_ssa_var += 1;
fx.bcx.declare_var(var, fx.clif_type(layout.ty).unwrap());
CPlace { inner: CPlaceInner::Var(local, var), layout }
}
pub(crate) fn new_var_pair(
fx: &mut FunctionCx<'_, '_, 'tcx>,
local: Local,
layout: TyAndLayout<'tcx>,
) -> CPlace<'tcx> {
let var1 = Variable::from_u32(fx.next_ssa_var);
fx.next_ssa_var += 1;
let var2 = Variable::from_u32(fx.next_ssa_var);
fx.next_ssa_var += 1;
let (ty1, ty2) = fx.clif_pair_type(layout.ty).unwrap();
fx.bcx.declare_var(var1, ty1);
fx.bcx.declare_var(var2, ty2);
CPlace { inner: CPlaceInner::VarPair(local, var1, var2), layout }
}
pub(crate) fn for_ptr(ptr: Pointer, layout: TyAndLayout<'tcx>) -> CPlace<'tcx> {
CPlace { inner: CPlaceInner::Addr(ptr, None), layout }
}
pub(crate) fn for_ptr_with_extra(
ptr: Pointer,
extra: Value,
layout: TyAndLayout<'tcx>,
) -> CPlace<'tcx> {
CPlace { inner: CPlaceInner::Addr(ptr, Some(extra)), layout }
}
pub(crate) fn to_cvalue(self, fx: &mut FunctionCx<'_, '_, 'tcx>) -> CValue<'tcx> {
let layout = self.layout();
match self.inner {
CPlaceInner::Var(_local, var) => {
let val = fx.bcx.use_var(var);
//fx.bcx.set_val_label(val, cranelift_codegen::ir::ValueLabel::new(var.index()));
CValue::by_val(val, layout)
}
CPlaceInner::VarPair(_local, var1, var2) => {
let val1 = fx.bcx.use_var(var1);
//fx.bcx.set_val_label(val1, cranelift_codegen::ir::ValueLabel::new(var1.index()));
let val2 = fx.bcx.use_var(var2);
//fx.bcx.set_val_label(val2, cranelift_codegen::ir::ValueLabel::new(var2.index()));
CValue::by_val_pair(val1, val2, layout)
}
CPlaceInner::Addr(ptr, extra) => {
if let Some(extra) = extra {
CValue::by_ref_unsized(ptr, extra, layout)
} else {
CValue::by_ref(ptr, layout)
}
}
}
}
pub(crate) fn debug_comment(self) -> (&'static str, String) {
match self.inner {
CPlaceInner::Var(_local, var) => ("ssa", format!("var={}", var.index())),
CPlaceInner::VarPair(_local, var1, var2) => {
("ssa", format!("var=({}, {})", var1.index(), var2.index()))
}
CPlaceInner::Addr(ptr, meta) => {
let meta =
if let Some(meta) = meta { format!(",meta={}", meta) } else { String::new() };
match ptr.debug_base_and_offset() {
(crate::pointer::PointerBase::Addr(addr), offset) => {
("reuse", format!("storage={}{}{}", addr, offset, meta))
}
(crate::pointer::PointerBase::Stack(stack_slot), offset) => {
("stack", format!("storage={}{}{}", stack_slot, offset, meta))
}
(crate::pointer::PointerBase::Dangling(align), offset) => {
("zst", format!("align={},offset={}", align.bytes(), offset))
}
}
}
}
}
#[track_caller]
pub(crate) fn to_ptr(self) -> Pointer {
match self.inner {
CPlaceInner::Addr(ptr, None) => ptr,
CPlaceInner::Addr(_, Some(_)) => bug!("Expected sized cplace, found {:?}", self),
CPlaceInner::Var(_, _) | CPlaceInner::VarPair(_, _, _) => {
bug!("Expected CPlace::Addr, found {:?}", self)
}
}
}
#[track_caller]
pub(crate) fn to_ptr_unsized(self) -> (Pointer, Value) {
match self.inner {
CPlaceInner::Addr(ptr, Some(extra)) => (ptr, extra),
CPlaceInner::Addr(_, None) | CPlaceInner::Var(_, _) | CPlaceInner::VarPair(_, _, _) => {
bug!("Expected unsized cplace, found {:?}", self)
}
}
}
pub(crate) fn try_to_ptr(self) -> Option<Pointer> {
match self.inner {
CPlaceInner::Var(_, _) | CPlaceInner::VarPair(_, _, _) => None,
CPlaceInner::Addr(ptr, None) => Some(ptr),
CPlaceInner::Addr(_, Some(_)) => bug!("Expected sized cplace, found {:?}", self),
}
}
pub(crate) fn write_cvalue(self, fx: &mut FunctionCx<'_, '_, 'tcx>, from: CValue<'tcx>) {
assert_assignable(fx, from.layout().ty, self.layout().ty, 16);
self.write_cvalue_maybe_transmute(fx, from, "write_cvalue");
}
pub(crate) fn write_cvalue_transmute(
self,
fx: &mut FunctionCx<'_, '_, 'tcx>,
from: CValue<'tcx>,
) {
self.write_cvalue_maybe_transmute(fx, from, "write_cvalue_transmute");
}
fn write_cvalue_maybe_transmute(
self,
fx: &mut FunctionCx<'_, '_, 'tcx>,
from: CValue<'tcx>,
method: &'static str,
) {
fn transmute_scalar<'tcx>(
fx: &mut FunctionCx<'_, '_, 'tcx>,
var: Variable,
data: Value,
dst_ty: Type,
) {
let src_ty = fx.bcx.func.dfg.value_type(data);
assert_eq!(
src_ty.bytes(),
dst_ty.bytes(),
"write_cvalue_transmute: {:?} -> {:?}",
src_ty,
dst_ty,
);
let data = match (src_ty, dst_ty) {
(_, _) if src_ty == dst_ty => data,
// This is a `write_cvalue_transmute`.
(types::I32, types::F32)
| (types::F32, types::I32)
| (types::I64, types::F64)
| (types::F64, types::I64) => codegen_bitcast(fx, dst_ty, data),
_ if src_ty.is_vector() && dst_ty.is_vector() => codegen_bitcast(fx, dst_ty, data),
_ if src_ty.is_vector() || dst_ty.is_vector() => {
// FIXME(bytecodealliance/wasmtime#6104) do something more efficient for transmutes between vectors and integers.
let ptr = fx.create_stack_slot(src_ty.bytes(), src_ty.bytes());
ptr.store(fx, data, MemFlags::trusted());
ptr.load(fx, dst_ty, MemFlags::trusted())
}
// `CValue`s should never contain SSA-only types, so if you ended
// up here having seen an error like `B1 -> I8`, then before
// calling `write_cvalue` you need to add a `bint` instruction.
_ => unreachable!("write_cvalue_transmute: {:?} -> {:?}", src_ty, dst_ty),
};
//fx.bcx.set_val_label(data, cranelift_codegen::ir::ValueLabel::new(var.index()));
fx.bcx.def_var(var, data);
}
assert_eq!(self.layout().size, from.layout().size);
if fx.clif_comments.enabled() {
use cranelift_codegen::cursor::{Cursor, CursorPosition};
let cur_block = match fx.bcx.cursor().position() {
CursorPosition::After(block) => block,
_ => unreachable!(),
};
fx.add_comment(
fx.bcx.func.layout.last_inst(cur_block).unwrap(),
format!(
"{}: {:?}: {:?} <- {:?}: {:?}",
method,
self.inner,
self.layout().ty,
from.0,
from.layout().ty
),
);
}
let dst_layout = self.layout();
match self.inner {
CPlaceInner::Var(_local, var) => {
let data = match from.1.backend_repr {
BackendRepr::Scalar(_) => CValue(from.0, dst_layout).load_scalar(fx),
_ => {
let (ptr, meta) = from.force_stack(fx);
assert!(meta.is_none());
CValue(CValueInner::ByRef(ptr, None), dst_layout).load_scalar(fx)
}
};
let dst_ty = fx.clif_type(self.layout().ty).unwrap();
transmute_scalar(fx, var, data, dst_ty);
}
CPlaceInner::VarPair(_local, var1, var2) => {
let (data1, data2) = match from.1.backend_repr {
BackendRepr::ScalarPair(_, _) => {
CValue(from.0, dst_layout).load_scalar_pair(fx)
}
_ => {
let (ptr, meta) = from.force_stack(fx);
assert!(meta.is_none());
CValue(CValueInner::ByRef(ptr, None), dst_layout).load_scalar_pair(fx)
}
};
let (dst_ty1, dst_ty2) = fx.clif_pair_type(self.layout().ty).unwrap();
transmute_scalar(fx, var1, data1, dst_ty1);
transmute_scalar(fx, var2, data2, dst_ty2);
}
CPlaceInner::Addr(_, Some(_)) => bug!("Can't write value to unsized place {:?}", self),
CPlaceInner::Addr(to_ptr, None) => {
if dst_layout.size == Size::ZERO
|| dst_layout.backend_repr == BackendRepr::Uninhabited
{
return;
}
let mut flags = MemFlags::new();
flags.set_notrap();
match from.0 {
CValueInner::ByVal(val) => {
to_ptr.store(fx, val, flags);
}
CValueInner::ByValPair(val1, val2) => match from.layout().backend_repr {
BackendRepr::ScalarPair(a_scalar, b_scalar) => {
let b_offset =
scalar_pair_calculate_b_offset(fx.tcx, a_scalar, b_scalar);
to_ptr.store(fx, val1, flags);
to_ptr.offset(fx, b_offset).store(fx, val2, flags);
}
_ => {
bug!(
"Non ScalarPair repr {:?} for ByValPair CValue",
dst_layout.backend_repr
)
}
},
CValueInner::ByRef(from_ptr, None) => {
match from.layout().backend_repr {
BackendRepr::Scalar(_) => {
let val = from.load_scalar(fx);
to_ptr.store(fx, val, flags);
return;
}
BackendRepr::ScalarPair(a_scalar, b_scalar) => {
let b_offset =
scalar_pair_calculate_b_offset(fx.tcx, a_scalar, b_scalar);
let (val1, val2) = from.load_scalar_pair(fx);
to_ptr.store(fx, val1, flags);
to_ptr.offset(fx, b_offset).store(fx, val2, flags);
return;
}
_ => {}
}
let from_addr = from_ptr.get_addr(fx);
let to_addr = to_ptr.get_addr(fx);
let src_layout = from.1;
let size = dst_layout.size.bytes();
// `emit_small_memory_copy` uses `u8` for alignments, just use the maximum
// alignment that fits in a `u8` if the actual alignment is larger.
let src_align = src_layout.align.abi.bytes().try_into().unwrap_or(128);
let dst_align = dst_layout.align.abi.bytes().try_into().unwrap_or(128);
fx.bcx.emit_small_memory_copy(
fx.target_config,
to_addr,
from_addr,
size,
dst_align,
src_align,
true,
flags,
);
}
CValueInner::ByRef(_, Some(_)) => todo!(),
}
}
}
}
/// Used for `ProjectionElem::Subtype`, `ty` has to be monomorphized before
/// passed on.
pub(crate) fn place_transmute_type(
self,
fx: &mut FunctionCx<'_, '_, 'tcx>,
ty: Ty<'tcx>,
) -> CPlace<'tcx> {
CPlace { inner: self.inner, layout: fx.layout_of(ty) }
}
pub(crate) fn place_field(
self,
fx: &mut FunctionCx<'_, '_, 'tcx>,
field: FieldIdx,
) -> CPlace<'tcx> {
let layout = self.layout();
match self.inner {
CPlaceInner::VarPair(local, var1, var2) => {
let layout = layout.field(&*fx, field.index());
match field.as_u32() {
0 => return CPlace { inner: CPlaceInner::Var(local, var1), layout },
1 => return CPlace { inner: CPlaceInner::Var(local, var2), layout },
_ => unreachable!("field should be 0 or 1"),
}
}
_ => {}
}
let (base, extra) = match self.inner {
CPlaceInner::Addr(ptr, extra) => (ptr, extra),
CPlaceInner::Var(_, _) | CPlaceInner::VarPair(_, _, _) => {
bug!("Expected CPlace::Addr, found {:?}", self)
}
};
let (field_ptr, field_layout) = codegen_field(fx, base, extra, layout, field);
if has_ptr_meta(fx.tcx, field_layout.ty) {
CPlace::for_ptr_with_extra(field_ptr, extra.unwrap(), field_layout)
} else {
CPlace::for_ptr(field_ptr, field_layout)
}
}
/// Like [`CPlace::place_field`] except handling ADTs containing a single array field in a way
/// such that you can access individual lanes.
pub(crate) fn place_lane(
self,
fx: &mut FunctionCx<'_, '_, 'tcx>,
lane_idx: u64,
) -> CPlace<'tcx> {
let layout = self.layout();
assert!(layout.ty.is_simd());
let (lane_count, lane_ty) = layout.ty.simd_size_and_type(fx.tcx);
let lane_layout = fx.layout_of(lane_ty);
assert!(lane_idx < lane_count);
match self.inner {
CPlaceInner::Var(_, _) => unreachable!(),
CPlaceInner::VarPair(_, _, _) => unreachable!(),
CPlaceInner::Addr(ptr, None) => {
let field_offset = lane_layout.size * lane_idx;
let field_ptr = ptr.offset_i64(fx, i64::try_from(field_offset.bytes()).unwrap());
CPlace::for_ptr(field_ptr, lane_layout)
}
CPlaceInner::Addr(_, Some(_)) => unreachable!(),
}
}
/// Like [`CPlace::place_field`] except using the passed type as lane type instead of the one
/// specified by the vector type.
pub(crate) fn place_typed_lane(
self,
fx: &mut FunctionCx<'_, '_, 'tcx>,
lane_ty: Ty<'tcx>,
lane_idx: u64,
) -> CPlace<'tcx> {
let layout = self.layout();
assert!(layout.ty.is_simd());
let (orig_lane_count, orig_lane_ty) = layout.ty.simd_size_and_type(fx.tcx);
let lane_layout = fx.layout_of(lane_ty);
assert!(
(lane_idx + 1) * lane_layout.size <= orig_lane_count * fx.layout_of(orig_lane_ty).size
);
match self.inner {
CPlaceInner::Var(_, _) => unreachable!(),
CPlaceInner::VarPair(_, _, _) => unreachable!(),
CPlaceInner::Addr(ptr, None) => {
let field_offset = lane_layout.size * lane_idx;
let field_ptr = ptr.offset_i64(fx, i64::try_from(field_offset.bytes()).unwrap());
CPlace::for_ptr(field_ptr, lane_layout)
}
CPlaceInner::Addr(_, Some(_)) => unreachable!(),
}
}
pub(crate) fn place_index(
self,
fx: &mut FunctionCx<'_, '_, 'tcx>,
index: Value,
) -> CPlace<'tcx> {
let (elem_layout, ptr) = match self.layout().ty.kind() {
ty::Array(elem_ty, _) => {
let elem_layout = fx.layout_of(*elem_ty);
match self.inner {
CPlaceInner::Addr(addr, None) => (elem_layout, addr),
CPlaceInner::Var(_, _)
| CPlaceInner::Addr(_, Some(_))
| CPlaceInner::VarPair(_, _, _) => bug!("Can't index into {self:?}"),
}
}
ty::Slice(elem_ty) => (fx.layout_of(*elem_ty), self.to_ptr_unsized().0),
_ => bug!("place_index({:?})", self.layout().ty),
};
let offset = fx.bcx.ins().imul_imm(index, elem_layout.size.bytes() as i64);
CPlace::for_ptr(ptr.offset_value(fx, offset), elem_layout)
}
pub(crate) fn place_deref(self, fx: &mut FunctionCx<'_, '_, 'tcx>) -> CPlace<'tcx> {
let inner_layout = fx.layout_of(self.layout().ty.builtin_deref(true).unwrap());
if has_ptr_meta(fx.tcx, inner_layout.ty) {
let (addr, extra) = self.to_cvalue(fx).load_scalar_pair(fx);
CPlace::for_ptr_with_extra(Pointer::new(addr), extra, inner_layout)
} else {
CPlace::for_ptr(Pointer::new(self.to_cvalue(fx).load_scalar(fx)), inner_layout)
}
}
pub(crate) fn place_ref(
self,
fx: &mut FunctionCx<'_, '_, 'tcx>,
layout: TyAndLayout<'tcx>,
) -> CValue<'tcx> {
if has_ptr_meta(fx.tcx, self.layout().ty) {
let (ptr, extra) = self.to_ptr_unsized();
CValue::by_val_pair(ptr.get_addr(fx), extra, layout)
} else {
CValue::by_val(self.to_ptr().get_addr(fx), layout)
}
}
pub(crate) fn downcast_variant(
self,
fx: &FunctionCx<'_, '_, 'tcx>,
variant: VariantIdx,
) -> Self {
assert!(self.layout().is_sized());
let layout = self.layout().for_variant(fx, variant);
CPlace { inner: self.inner, layout }
}
}
#[track_caller]
pub(crate) fn assert_assignable<'tcx>(
fx: &FunctionCx<'_, '_, 'tcx>,
from_ty: Ty<'tcx>,
to_ty: Ty<'tcx>,
limit: usize,
) {
if limit == 0 {
// assert_assignable exists solely to catch bugs in cg_clif. it isn't necessary for
// soundness. don't attempt to check deep types to avoid exponential behavior in certain
// cases.
return;
}
match (from_ty.kind(), to_ty.kind()) {
(ty::Ref(_, a, _), ty::Ref(_, b, _)) | (ty::RawPtr(a, _), ty::RawPtr(b, _)) => {
assert_assignable(fx, *a, *b, limit - 1);
}
(ty::Ref(_, a, _), ty::RawPtr(b, _)) | (ty::RawPtr(a, _), ty::Ref(_, b, _)) => {
assert_assignable(fx, *a, *b, limit - 1);
}
(ty::FnPtr(..), ty::FnPtr(..)) => {
let from_sig = fx
.tcx
.normalize_erasing_late_bound_regions(fx.typing_env(), from_ty.fn_sig(fx.tcx));
let FnSig {
inputs_and_output: types_from,
c_variadic: c_variadic_from,
safety: unsafety_from,
abi: abi_from,
} = from_sig;
let to_sig =
fx.tcx.normalize_erasing_late_bound_regions(fx.typing_env(), to_ty.fn_sig(fx.tcx));
let FnSig {
inputs_and_output: types_to,
c_variadic: c_variadic_to,
safety: unsafety_to,
abi: abi_to,
} = to_sig;
let mut types_from = types_from.iter();
let mut types_to = types_to.iter();
loop {
match (types_from.next(), types_to.next()) {
(Some(a), Some(b)) => assert_assignable(fx, a, b, limit - 1),
(None, None) => break,
(Some(_), None) | (None, Some(_)) => panic!("{:#?}/{:#?}", from_ty, to_ty),
}
}
assert_eq!(
c_variadic_from, c_variadic_to,
"Can't write fn ptr with incompatible sig {:?} to place with sig {:?}\n\n{:#?}",
from_sig, to_sig, fx,
);
assert_eq!(
unsafety_from, unsafety_to,
"Can't write fn ptr with incompatible sig {:?} to place with sig {:?}\n\n{:#?}",
from_sig, to_sig, fx,
);
assert_eq!(
abi_from, abi_to,
"Can't write fn ptr with incompatible sig {:?} to place with sig {:?}\n\n{:#?}",
from_sig, to_sig, fx,
);
// fn(&T) -> for<'l> fn(&'l T) is allowed
}
(&ty::Dynamic(from_traits, _, _from_kind), &ty::Dynamic(to_traits, _, _to_kind)) => {
// FIXME(dyn-star): Do the right thing with DynKinds
for (from, to) in from_traits.iter().zip(to_traits) {
let from = fx.tcx.normalize_erasing_late_bound_regions(fx.typing_env(), from);
let to = fx.tcx.normalize_erasing_late_bound_regions(fx.typing_env(), to);
assert_eq!(
from, to,
"Can't write trait object of incompatible traits {:?} to place with traits {:?}\n\n{:#?}",
from_traits, to_traits, fx,
);
}
// dyn for<'r> Trait<'r> -> dyn Trait<'_> is allowed
}
(&ty::Tuple(types_a), &ty::Tuple(types_b)) => {
let mut types_a = types_a.iter();
let mut types_b = types_b.iter();
loop {
match (types_a.next(), types_b.next()) {
(Some(a), Some(b)) => assert_assignable(fx, a, b, limit - 1),
(None, None) => return,
(Some(_), None) | (None, Some(_)) => panic!("{:#?}/{:#?}", from_ty, to_ty),
}
}
}
(&ty::Adt(adt_def_a, args_a), &ty::Adt(adt_def_b, args_b))
if adt_def_a.did() == adt_def_b.did() =>
{
let mut types_a = args_a.types();
let mut types_b = args_b.types();
loop {
match (types_a.next(), types_b.next()) {
(Some(a), Some(b)) => assert_assignable(fx, a, b, limit - 1),
(None, None) => return,
(Some(_), None) | (None, Some(_)) => panic!("{:#?}/{:#?}", from_ty, to_ty),
}
}
}
(ty::Array(a, _), ty::Array(b, _)) => assert_assignable(fx, *a, *b, limit - 1),
(&ty::Closure(def_id_a, args_a), &ty::Closure(def_id_b, args_b))
if def_id_a == def_id_b =>
{
let mut types_a = args_a.types();
let mut types_b = args_b.types();
loop {
match (types_a.next(), types_b.next()) {
(Some(a), Some(b)) => assert_assignable(fx, a, b, limit - 1),
(None, None) => return,
(Some(_), None) | (None, Some(_)) => panic!("{:#?}/{:#?}", from_ty, to_ty),
}
}
}
(&ty::Coroutine(def_id_a, args_a), &ty::Coroutine(def_id_b, args_b))
if def_id_a == def_id_b =>
{
let mut types_a = args_a.types();
let mut types_b = args_b.types();
loop {
match (types_a.next(), types_b.next()) {
(Some(a), Some(b)) => assert_assignable(fx, a, b, limit - 1),
(None, None) => return,
(Some(_), None) | (None, Some(_)) => panic!("{:#?}/{:#?}", from_ty, to_ty),
}
}
}
(&ty::CoroutineWitness(def_id_a, args_a), &ty::CoroutineWitness(def_id_b, args_b))
if def_id_a == def_id_b =>
{
let mut types_a = args_a.types();
let mut types_b = args_b.types();
loop {
match (types_a.next(), types_b.next()) {
(Some(a), Some(b)) => assert_assignable(fx, a, b, limit - 1),
(None, None) => return,
(Some(_), None) | (None, Some(_)) => panic!("{:#?}/{:#?}", from_ty, to_ty),
}
}
}
(ty::Param(_), _) | (_, ty::Param(_)) if fx.tcx.sess.opts.unstable_opts.polymorphize => {
// No way to check if it is correct or not with polymorphization enabled
}
_ => {
assert_eq!(
from_ty,
to_ty,
"Can't write value with incompatible type {:?} to place with type {:?}\n\n{:#?}",
from_ty.kind(),
to_ty.kind(),
fx,
);
}
}
}