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Auto merge of #94527 - oli-obk:undef_scalars, r=nagisa,erikdesjardin
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Let CTFE to handle partially uninitialized unions without marking the entire value as uninitialized.

follow up to #94411

To fix #69488 and by extension fix #94371, we should stop treating types like `MaybeUninit<usize>` as something that the `Scalar` type in the interpreter engine can represent. So we add a new field to `abi::Primitive` that records whether the primitive is nested in a union

cc `@RalfJung`

r? `@ghost`
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@bors
bors committed Apr 5, 2022
2 parents d4c7839 + d57b755 commit f262ca1
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Showing 42 changed files with 467 additions and 334 deletions.
2 changes: 1 addition & 1 deletion compiler/rustc_codegen_cranelift/src/common.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -21,7 +21,7 @@ pub(crate) fn pointer_ty(tcx: TyCtxt<'_>) -> types::Type {
}

pub(crate) fn scalar_to_clif_type(tcx: TyCtxt<'_>, scalar: Scalar) -> Type {
match scalar.value {
match scalar.primitive() {
Primitive::Int(int, _sign) => match int {
Integer::I8 => types::I8,
Integer::I16 => types::I16,
Expand Down
2 changes: 1 addition & 1 deletion compiler/rustc_codegen_cranelift/src/discriminant.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -105,7 +105,7 @@ pub(crate) fn codegen_get_discriminant<'tcx>(
// Decode the discriminant (specifically if it's niche-encoded).
match *tag_encoding {
TagEncoding::Direct => {
let signed = match tag_scalar.value {
let signed = match tag_scalar.primitive() {
Int(_, signed) => signed,
_ => false,
};
Expand Down
2 changes: 1 addition & 1 deletion compiler/rustc_codegen_cranelift/src/value_and_place.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -50,7 +50,7 @@ fn codegen_field<'tcx>(
}

fn scalar_pair_calculate_b_offset(tcx: TyCtxt<'_>, a_scalar: Scalar, b_scalar: Scalar) -> Offset32 {
let b_offset = a_scalar.value.size(&tcx).align_to(b_scalar.value.align(&tcx).abi);
let b_offset = a_scalar.size(&tcx).align_to(b_scalar.align(&tcx).abi);
Offset32::new(b_offset.bytes().try_into().unwrap())
}

Expand Down
8 changes: 4 additions & 4 deletions compiler/rustc_codegen_gcc/src/builder.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -694,11 +694,11 @@ impl<'a, 'gcc, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'gcc, 'tcx> {
}

fn scalar_load_metadata<'a, 'gcc, 'tcx>(bx: &mut Builder<'a, 'gcc, 'tcx>, load: RValue<'gcc>, scalar: &abi::Scalar) {
let vr = scalar.valid_range.clone();
match scalar.value {
let vr = scalar.valid_range(bx);
match scalar.primitive() {
abi::Int(..) => {
if !scalar.is_always_valid(bx) {
bx.range_metadata(load, scalar.valid_range);
bx.range_metadata(load, vr);
}
}
abi::Pointer if vr.start < vr.end && !vr.contains(0) => {
Expand All @@ -720,7 +720,7 @@ impl<'a, 'gcc, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'gcc, 'tcx> {
OperandValue::Immediate(self.to_immediate(load, place.layout))
}
else if let abi::Abi::ScalarPair(ref a, ref b) = place.layout.abi {
let b_offset = a.value.size(self).align_to(b.value.align(self).abi);
let b_offset = a.size(self).align_to(b.align(self).abi);
let pair_type = place.layout.gcc_type(self, false);

let mut load = |i, scalar: &abi::Scalar, align| {
Expand Down
8 changes: 4 additions & 4 deletions compiler/rustc_codegen_gcc/src/common.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -158,14 +158,14 @@ impl<'gcc, 'tcx> ConstMethods<'tcx> for CodegenCx<'gcc, 'tcx> {
}

fn scalar_to_backend(&self, cv: Scalar, layout: abi::Scalar, ty: Type<'gcc>) -> RValue<'gcc> {
let bitsize = if layout.is_bool() { 1 } else { layout.value.size(self).bits() };
let bitsize = if layout.is_bool() { 1 } else { layout.size(self).bits() };
match cv {
Scalar::Int(ScalarInt::ZST) => {
assert_eq!(0, layout.value.size(self).bytes());
assert_eq!(0, layout.size(self).bytes());
self.const_undef(self.type_ix(0))
}
Scalar::Int(int) => {
let data = int.assert_bits(layout.value.size(self));
let data = int.assert_bits(layout.size(self));

// FIXME(antoyo): there's some issues with using the u128 code that follows, so hard-code
// the paths for floating-point values.
Expand Down Expand Up @@ -209,7 +209,7 @@ impl<'gcc, 'tcx> ConstMethods<'tcx> for CodegenCx<'gcc, 'tcx> {
let base_addr = self.const_bitcast(base_addr, self.usize_type);
let offset = self.context.new_rvalue_from_long(self.usize_type, offset.bytes() as i64);
let ptr = self.const_bitcast(base_addr + offset, ptr_type);
if layout.value != Pointer {
if layout.primitive() != Pointer {
self.const_bitcast(ptr.dereference(None).to_rvalue(), ty)
}
else {
Expand Down
2 changes: 1 addition & 1 deletion compiler/rustc_codegen_gcc/src/consts.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -328,7 +328,7 @@ pub fn const_alloc_to_gcc<'gcc, 'tcx>(cx: &CodegenCx<'gcc, 'tcx>, alloc: ConstAl
interpret::Pointer::new(alloc_id, Size::from_bytes(ptr_offset)),
&cx.tcx,
),
abi::Scalar { value: Primitive::Pointer, valid_range: WrappingRange { start: 0, end: !0 } },
abi::Scalar::Initialized { value: Primitive::Pointer, valid_range: WrappingRange::full(dl.pointer_size) },
cx.type_i8p(),
));
next_offset = offset + pointer_size;
Expand Down
4 changes: 2 additions & 2 deletions compiler/rustc_codegen_gcc/src/type_of.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -224,7 +224,7 @@ impl<'tcx> LayoutGccExt<'tcx> for TyAndLayout<'tcx> {
}

fn scalar_gcc_type_at<'gcc>(&self, cx: &CodegenCx<'gcc, 'tcx>, scalar: &abi::Scalar, offset: Size) -> Type<'gcc> {
match scalar.value {
match scalar.primitive() {
Int(i, true) => cx.type_from_integer(i),
Int(i, false) => cx.type_from_unsigned_integer(i),
F32 => cx.type_f32(),
Expand Down Expand Up @@ -282,7 +282,7 @@ impl<'tcx> LayoutGccExt<'tcx> for TyAndLayout<'tcx> {
Size::ZERO
}
else {
a.value.size(cx).align_to(b.value.align(cx).abi)
a.size(cx).align_to(b.align(cx).abi)
};
self.scalar_gcc_type_at(cx, scalar, offset)
}
Expand Down
4 changes: 2 additions & 2 deletions compiler/rustc_codegen_llvm/src/abi.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -510,9 +510,9 @@ impl<'ll, 'tcx> FnAbiLlvmExt<'ll, 'tcx> for FnAbi<'tcx, Ty<'tcx>> {
// If the value is a boolean, the range is 0..2 and that ultimately
// become 0..0 when the type becomes i1, which would be rejected
// by the LLVM verifier.
if let Int(..) = scalar.value {
if let Int(..) = scalar.primitive() {
if !scalar.is_bool() && !scalar.is_always_valid(bx) {
bx.range_metadata(callsite, scalar.valid_range);
bx.range_metadata(callsite, scalar.valid_range(bx));
}
}
}
Expand Down
80 changes: 43 additions & 37 deletions compiler/rustc_codegen_llvm/src/asm.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -753,7 +753,7 @@ fn dummy_output_type<'ll>(cx: &CodegenCx<'ll, '_>, reg: InlineAsmRegClass) -> &'
/// Helper function to get the LLVM type for a Scalar. Pointers are returned as
/// the equivalent integer type.
fn llvm_asm_scalar_type<'ll>(cx: &CodegenCx<'ll, '_>, scalar: Scalar) -> &'ll Type {
match scalar.value {
match scalar.primitive() {
Primitive::Int(Integer::I8, _) => cx.type_i8(),
Primitive::Int(Integer::I16, _) => cx.type_i16(),
Primitive::Int(Integer::I32, _) => cx.type_i32(),
Expand All @@ -774,7 +774,7 @@ fn llvm_fixup_input<'ll, 'tcx>(
) -> &'ll Value {
match (reg, layout.abi) {
(InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::vreg), Abi::Scalar(s)) => {
if let Primitive::Int(Integer::I8, _) = s.value {
if let Primitive::Int(Integer::I8, _) = s.primitive() {
let vec_ty = bx.cx.type_vector(bx.cx.type_i8(), 8);
bx.insert_element(bx.const_undef(vec_ty), value, bx.const_i32(0))
} else {
Expand All @@ -785,7 +785,7 @@ fn llvm_fixup_input<'ll, 'tcx>(
let elem_ty = llvm_asm_scalar_type(bx.cx, s);
let count = 16 / layout.size.bytes();
let vec_ty = bx.cx.type_vector(elem_ty, count);
if let Primitive::Pointer = s.value {
if let Primitive::Pointer = s.primitive() {
value = bx.ptrtoint(value, bx.cx.type_isize());
}
bx.insert_element(bx.const_undef(vec_ty), value, bx.const_i32(0))
Expand All @@ -800,7 +800,7 @@ fn llvm_fixup_input<'ll, 'tcx>(
bx.shuffle_vector(value, bx.const_undef(vec_ty), bx.const_vector(&indices))
}
(InlineAsmRegClass::X86(X86InlineAsmRegClass::reg_abcd), Abi::Scalar(s))
if s.value == Primitive::F64 =>
if s.primitive() == Primitive::F64 =>
{
bx.bitcast(value, bx.cx.type_i64())
}
Expand All @@ -812,7 +812,7 @@ fn llvm_fixup_input<'ll, 'tcx>(
InlineAsmRegClass::Arm(ArmInlineAsmRegClass::sreg | ArmInlineAsmRegClass::sreg_low16),
Abi::Scalar(s),
) => {
if let Primitive::Int(Integer::I32, _) = s.value {
if let Primitive::Int(Integer::I32, _) = s.primitive() {
bx.bitcast(value, bx.cx.type_f32())
} else {
value
Expand All @@ -826,19 +826,21 @@ fn llvm_fixup_input<'ll, 'tcx>(
),
Abi::Scalar(s),
) => {
if let Primitive::Int(Integer::I64, _) = s.value {
if let Primitive::Int(Integer::I64, _) = s.primitive() {
bx.bitcast(value, bx.cx.type_f64())
} else {
value
}
}
(InlineAsmRegClass::Mips(MipsInlineAsmRegClass::reg), Abi::Scalar(s)) => match s.value {
// MIPS only supports register-length arithmetics.
Primitive::Int(Integer::I8 | Integer::I16, _) => bx.zext(value, bx.cx.type_i32()),
Primitive::F32 => bx.bitcast(value, bx.cx.type_i32()),
Primitive::F64 => bx.bitcast(value, bx.cx.type_i64()),
_ => value,
},
(InlineAsmRegClass::Mips(MipsInlineAsmRegClass::reg), Abi::Scalar(s)) => {
match s.primitive() {
// MIPS only supports register-length arithmetics.
Primitive::Int(Integer::I8 | Integer::I16, _) => bx.zext(value, bx.cx.type_i32()),
Primitive::F32 => bx.bitcast(value, bx.cx.type_i32()),
Primitive::F64 => bx.bitcast(value, bx.cx.type_i64()),
_ => value,
}
}
_ => value,
}
}
Expand All @@ -852,15 +854,15 @@ fn llvm_fixup_output<'ll, 'tcx>(
) -> &'ll Value {
match (reg, layout.abi) {
(InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::vreg), Abi::Scalar(s)) => {
if let Primitive::Int(Integer::I8, _) = s.value {
if let Primitive::Int(Integer::I8, _) = s.primitive() {
bx.extract_element(value, bx.const_i32(0))
} else {
value
}
}
(InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::vreg_low16), Abi::Scalar(s)) => {
value = bx.extract_element(value, bx.const_i32(0));
if let Primitive::Pointer = s.value {
if let Primitive::Pointer = s.primitive() {
value = bx.inttoptr(value, layout.llvm_type(bx.cx));
}
value
Expand All @@ -875,7 +877,7 @@ fn llvm_fixup_output<'ll, 'tcx>(
bx.shuffle_vector(value, bx.const_undef(vec_ty), bx.const_vector(&indices))
}
(InlineAsmRegClass::X86(X86InlineAsmRegClass::reg_abcd), Abi::Scalar(s))
if s.value == Primitive::F64 =>
if s.primitive() == Primitive::F64 =>
{
bx.bitcast(value, bx.cx.type_f64())
}
Expand All @@ -887,7 +889,7 @@ fn llvm_fixup_output<'ll, 'tcx>(
InlineAsmRegClass::Arm(ArmInlineAsmRegClass::sreg | ArmInlineAsmRegClass::sreg_low16),
Abi::Scalar(s),
) => {
if let Primitive::Int(Integer::I32, _) = s.value {
if let Primitive::Int(Integer::I32, _) = s.primitive() {
bx.bitcast(value, bx.cx.type_i32())
} else {
value
Expand All @@ -901,20 +903,22 @@ fn llvm_fixup_output<'ll, 'tcx>(
),
Abi::Scalar(s),
) => {
if let Primitive::Int(Integer::I64, _) = s.value {
if let Primitive::Int(Integer::I64, _) = s.primitive() {
bx.bitcast(value, bx.cx.type_i64())
} else {
value
}
}
(InlineAsmRegClass::Mips(MipsInlineAsmRegClass::reg), Abi::Scalar(s)) => match s.value {
// MIPS only supports register-length arithmetics.
Primitive::Int(Integer::I8, _) => bx.trunc(value, bx.cx.type_i8()),
Primitive::Int(Integer::I16, _) => bx.trunc(value, bx.cx.type_i16()),
Primitive::F32 => bx.bitcast(value, bx.cx.type_f32()),
Primitive::F64 => bx.bitcast(value, bx.cx.type_f64()),
_ => value,
},
(InlineAsmRegClass::Mips(MipsInlineAsmRegClass::reg), Abi::Scalar(s)) => {
match s.primitive() {
// MIPS only supports register-length arithmetics.
Primitive::Int(Integer::I8, _) => bx.trunc(value, bx.cx.type_i8()),
Primitive::Int(Integer::I16, _) => bx.trunc(value, bx.cx.type_i16()),
Primitive::F32 => bx.bitcast(value, bx.cx.type_f32()),
Primitive::F64 => bx.bitcast(value, bx.cx.type_f64()),
_ => value,
}
}
_ => value,
}
}
Expand All @@ -927,7 +931,7 @@ fn llvm_fixup_output_type<'ll, 'tcx>(
) -> &'ll Type {
match (reg, layout.abi) {
(InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::vreg), Abi::Scalar(s)) => {
if let Primitive::Int(Integer::I8, _) = s.value {
if let Primitive::Int(Integer::I8, _) = s.primitive() {
cx.type_vector(cx.type_i8(), 8)
} else {
layout.llvm_type(cx)
Expand All @@ -946,7 +950,7 @@ fn llvm_fixup_output_type<'ll, 'tcx>(
cx.type_vector(elem_ty, count * 2)
}
(InlineAsmRegClass::X86(X86InlineAsmRegClass::reg_abcd), Abi::Scalar(s))
if s.value == Primitive::F64 =>
if s.primitive() == Primitive::F64 =>
{
cx.type_i64()
}
Expand All @@ -958,7 +962,7 @@ fn llvm_fixup_output_type<'ll, 'tcx>(
InlineAsmRegClass::Arm(ArmInlineAsmRegClass::sreg | ArmInlineAsmRegClass::sreg_low16),
Abi::Scalar(s),
) => {
if let Primitive::Int(Integer::I32, _) = s.value {
if let Primitive::Int(Integer::I32, _) = s.primitive() {
cx.type_f32()
} else {
layout.llvm_type(cx)
Expand All @@ -972,19 +976,21 @@ fn llvm_fixup_output_type<'ll, 'tcx>(
),
Abi::Scalar(s),
) => {
if let Primitive::Int(Integer::I64, _) = s.value {
if let Primitive::Int(Integer::I64, _) = s.primitive() {
cx.type_f64()
} else {
layout.llvm_type(cx)
}
}
(InlineAsmRegClass::Mips(MipsInlineAsmRegClass::reg), Abi::Scalar(s)) => match s.value {
// MIPS only supports register-length arithmetics.
Primitive::Int(Integer::I8 | Integer::I16, _) => cx.type_i32(),
Primitive::F32 => cx.type_i32(),
Primitive::F64 => cx.type_i64(),
_ => layout.llvm_type(cx),
},
(InlineAsmRegClass::Mips(MipsInlineAsmRegClass::reg), Abi::Scalar(s)) => {
match s.primitive() {
// MIPS only supports register-length arithmetics.
Primitive::Int(Integer::I8 | Integer::I16, _) => cx.type_i32(),
Primitive::F32 => cx.type_i32(),
Primitive::F64 => cx.type_i64(),
_ => layout.llvm_type(cx),
}
}
_ => layout.llvm_type(cx),
}
}
8 changes: 4 additions & 4 deletions compiler/rustc_codegen_llvm/src/builder.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -484,14 +484,14 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
bx.noundef_metadata(load);
}

match scalar.value {
match scalar.primitive() {
abi::Int(..) => {
if !scalar.is_always_valid(bx) {
bx.range_metadata(load, scalar.valid_range);
bx.range_metadata(load, scalar.valid_range(bx));
}
}
abi::Pointer => {
if !scalar.valid_range.contains(0) {
if !scalar.valid_range(bx).contains(0) {
bx.nonnull_metadata(load);
}

Expand Down Expand Up @@ -525,7 +525,7 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
});
OperandValue::Immediate(self.to_immediate(llval, place.layout))
} else if let abi::Abi::ScalarPair(a, b) = place.layout.abi {
let b_offset = a.value.size(self).align_to(b.value.align(self).abi);
let b_offset = a.size(self).align_to(b.align(self).abi);
let pair_ty = place.layout.llvm_type(self);

let mut load = |i, scalar: abi::Scalar, layout, align, offset| {
Expand Down
10 changes: 5 additions & 5 deletions compiler/rustc_codegen_llvm/src/common.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -221,16 +221,16 @@ impl<'ll, 'tcx> ConstMethods<'tcx> for CodegenCx<'ll, 'tcx> {
}

fn scalar_to_backend(&self, cv: Scalar, layout: abi::Scalar, llty: &'ll Type) -> &'ll Value {
let bitsize = if layout.is_bool() { 1 } else { layout.value.size(self).bits() };
let bitsize = if layout.is_bool() { 1 } else { layout.size(self).bits() };
match cv {
Scalar::Int(ScalarInt::ZST) => {
assert_eq!(0, layout.value.size(self).bytes());
assert_eq!(0, layout.size(self).bytes());
self.const_undef(self.type_ix(0))
}
Scalar::Int(int) => {
let data = int.assert_bits(layout.value.size(self));
let data = int.assert_bits(layout.size(self));
let llval = self.const_uint_big(self.type_ix(bitsize), data);
if layout.value == Pointer {
if layout.primitive() == Pointer {
unsafe { llvm::LLVMConstIntToPtr(llval, llty) }
} else {
self.const_bitcast(llval, llty)
Expand Down Expand Up @@ -269,7 +269,7 @@ impl<'ll, 'tcx> ConstMethods<'tcx> for CodegenCx<'ll, 'tcx> {
1,
)
};
if layout.value != Pointer {
if layout.primitive() != Pointer {
unsafe { llvm::LLVMConstPtrToInt(llval, llty) }
} else {
self.const_bitcast(llval, llty)
Expand Down
5 changes: 4 additions & 1 deletion compiler/rustc_codegen_llvm/src/consts.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -109,7 +109,10 @@ pub fn const_alloc_to_llvm<'ll>(cx: &CodegenCx<'ll, '_>, alloc: ConstAllocation<
Pointer::new(alloc_id, Size::from_bytes(ptr_offset)),
&cx.tcx,
),
Scalar { value: Primitive::Pointer, valid_range: WrappingRange { start: 0, end: !0 } },
Scalar::Initialized {
value: Primitive::Pointer,
valid_range: WrappingRange::full(dl.pointer_size),
},
cx.type_i8p_ext(address_space),
));
next_offset = offset + pointer_size;
Expand Down
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