no-unique-address.cpp
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// RUN: %clang_cc1 -std=c++2a -fsyntax-only -triple x86_64-linux-gnu -fdump-record-layouts %s | FileCheck %s
namespace Empty {
struct A {};
struct B { [[no_unique_address]] A a; char b; };
static_assert(sizeof(B) == 1);
// CHECK:*** Dumping AST Record Layout
// CHECK: 0 | struct Empty::B
// CHECK-NEXT: 0 | struct Empty::A a (empty)
// CHECK-NEXT: 0 | char b
// CHECK-NEXT: | [sizeof=1, dsize=1, align=1,
// CHECK-NEXT: | nvsize=1, nvalign=1]
struct C {};
struct D {
[[no_unique_address]] A a;
[[no_unique_address]] C c;
char d;
};
static_assert(sizeof(D) == 1);
// CHECK:*** Dumping AST Record Layout
// CHECK: 0 | struct Empty::D
// CHECK-NEXT: 0 | struct Empty::A a (empty)
// CHECK-NEXT: 0 | struct Empty::C c (empty)
// CHECK-NEXT: 0 | char d
// CHECK-NEXT: | [sizeof=1, dsize=1, align=1,
// CHECK-NEXT: | nvsize=1, nvalign=1]
struct E {
[[no_unique_address]] A a1;
[[no_unique_address]] A a2;
char e;
};
static_assert(sizeof(E) == 2);
// CHECK:*** Dumping AST Record Layout
// CHECK: 0 | struct Empty::E
// CHECK-NEXT: 0 | struct Empty::A a1 (empty)
// CHECK-NEXT: 1 | struct Empty::A a2 (empty)
// CHECK-NEXT: 0 | char e
// CHECK-NEXT: | [sizeof=2, dsize=2, align=1,
// CHECK-NEXT: | nvsize=2, nvalign=1]
struct F {
~F();
[[no_unique_address]] A a1;
[[no_unique_address]] A a2;
char f;
};
static_assert(sizeof(F) == 2);
// CHECK:*** Dumping AST Record Layout
// CHECK: 0 | struct Empty::F
// CHECK-NEXT: 0 | struct Empty::A a1 (empty)
// CHECK-NEXT: 1 | struct Empty::A a2 (empty)
// CHECK-NEXT: 0 | char f
// CHECK-NEXT: | [sizeof=2, dsize=1, align=1,
// CHECK-NEXT: | nvsize=2, nvalign=1]
struct G { [[no_unique_address]] A a; ~G(); };
static_assert(sizeof(G) == 1);
// CHECK:*** Dumping AST Record Layout
// CHECK: 0 | struct Empty::G
// CHECK-NEXT: 0 | struct Empty::A a (empty)
// CHECK-NEXT: | [sizeof=1, dsize=0, align=1,
// CHECK-NEXT: | nvsize=1, nvalign=1]
struct H { [[no_unique_address]] A a, b; ~H(); };
static_assert(sizeof(H) == 2);
// CHECK:*** Dumping AST Record Layout
// CHECK: 0 | struct Empty::H
// CHECK-NEXT: 0 | struct Empty::A a (empty)
// CHECK-NEXT: 1 | struct Empty::A b (empty)
// CHECK-NEXT: | [sizeof=2, dsize=0, align=1,
// CHECK-NEXT: | nvsize=2, nvalign=1]
struct OversizedEmpty : A {
~OversizedEmpty();
[[no_unique_address]] A a;
};
static_assert(sizeof(OversizedEmpty) == 2);
// CHECK:*** Dumping AST Record Layout
// CHECK: 0 | struct Empty::OversizedEmpty
// CHECK-NEXT: 0 | struct Empty::A (base) (empty)
// CHECK-NEXT: 1 | struct Empty::A a (empty)
// CHECK-NEXT: | [sizeof=2, dsize=0, align=1,
// CHECK-NEXT: | nvsize=2, nvalign=1]
struct HasOversizedEmpty {
[[no_unique_address]] OversizedEmpty m;
};
static_assert(sizeof(HasOversizedEmpty) == 2);
// CHECK:*** Dumping AST Record Layout
// CHECK: 0 | struct Empty::HasOversizedEmpty
// CHECK-NEXT: 0 | struct Empty::OversizedEmpty m (empty)
// CHECK-NEXT: 0 | struct Empty::A (base) (empty)
// CHECK-NEXT: 1 | struct Empty::A a (empty)
// CHECK-NEXT: | [sizeof=2, dsize=0, align=1,
// CHECK-NEXT: | nvsize=2, nvalign=1]
struct EmptyWithNonzeroDSize {
[[no_unique_address]] A a;
int x;
[[no_unique_address]] A b;
int y;
[[no_unique_address]] A c;
};
static_assert(sizeof(EmptyWithNonzeroDSize) == 12);
// CHECK:*** Dumping AST Record Layout
// CHECK: 0 | struct Empty::EmptyWithNonzeroDSize
// CHECK-NEXT: 0 | struct Empty::A a (empty)
// CHECK-NEXT: 0 | int x
// CHECK-NEXT: 4 | struct Empty::A b (empty)
// CHECK-NEXT: 4 | int y
// CHECK-NEXT: 8 | struct Empty::A c (empty)
// CHECK-NEXT: | [sizeof=12, dsize=12, align=4,
// CHECK-NEXT: | nvsize=12, nvalign=4]
struct EmptyWithNonzeroDSizeNonPOD {
~EmptyWithNonzeroDSizeNonPOD();
[[no_unique_address]] A a;
int x;
[[no_unique_address]] A b;
int y;
[[no_unique_address]] A c;
};
static_assert(sizeof(EmptyWithNonzeroDSizeNonPOD) == 12);
// CHECK:*** Dumping AST Record Layout
// CHECK: 0 | struct Empty::EmptyWithNonzeroDSizeNonPOD
// CHECK-NEXT: 0 | struct Empty::A a (empty)
// CHECK-NEXT: 0 | int x
// CHECK-NEXT: 4 | struct Empty::A b (empty)
// CHECK-NEXT: 4 | int y
// CHECK-NEXT: 8 | struct Empty::A c (empty)
// CHECK-NEXT: | [sizeof=12, dsize=8, align=4,
// CHECK-NEXT: | nvsize=9, nvalign=4]
}
namespace POD {
// Cannot reuse tail padding of a PDO type.
struct A { int n; char c[3]; };
struct B { [[no_unique_address]] A a; char d; };
static_assert(sizeof(B) == 12);
// CHECK:*** Dumping AST Record Layout
// CHECK: 0 | struct POD::B
// CHECK-NEXT: 0 | struct POD::A a
// CHECK-NEXT: 0 | int n
// CHECK-NEXT: 4 | char [3] c
// CHECK-NEXT: 8 | char d
// CHECK-NEXT: | [sizeof=12, dsize=12, align=4,
// CHECK-NEXT: | nvsize=12, nvalign=4]
}
namespace NonPOD {
struct A { int n; char c[3]; ~A(); };
struct B { [[no_unique_address]] A a; char d; };
static_assert(sizeof(B) == 8);
// CHECK:*** Dumping AST Record Layout
// CHECK: 0 | struct NonPOD::B
// CHECK-NEXT: 0 | struct NonPOD::A a
// CHECK-NEXT: 0 | int n
// CHECK-NEXT: 4 | char [3] c
// CHECK-NEXT: 7 | char d
// CHECK-NEXT: | [sizeof=8, dsize=8, align=4,
// CHECK-NEXT: | nvsize=8, nvalign=4]
}
namespace NVSizeGreaterThanDSize {
// The nvsize of an object includes the complete size of its empty subobjects
// (although it's unclear why). Ensure this corner case is handled properly.
struct alignas(8) A { ~A(); }; // dsize 0, nvsize 0, size 8
struct B : A { char c; }; // dsize 1, nvsize 8, size 8
static_assert(sizeof(B) == 8);
// CHECK:*** Dumping AST Record Layout
// CHECK: 0 | struct NVSizeGreaterThanDSize::B
// CHECK-NEXT: 0 | struct NVSizeGreaterThanDSize::A (base) (empty)
// CHECK-NEXT: 0 | char c
// CHECK-NEXT: | [sizeof=8, dsize=1, align=8,
// CHECK-NEXT: | nvsize=8, nvalign=8]
struct V { int n; };
// V is at offset 16, not offset 12, because B's tail padding is strangely not
// usable for virtual bases.
struct C : B, virtual V {};
static_assert(sizeof(C) == 24);
// CHECK:*** Dumping AST Record Layout
// CHECK: 0 | struct NVSizeGreaterThanDSize::C
// CHECK-NEXT: 0 | (C vtable pointer)
// CHECK-NEXT: 8 | struct NVSizeGreaterThanDSize::B (base)
// CHECK-NEXT: 8 | struct NVSizeGreaterThanDSize::A (base) (empty)
// CHECK-NEXT: 8 | char c
// CHECK-NEXT: 16 | struct NVSizeGreaterThanDSize::V (virtual base)
// CHECK-NEXT: 16 | int n
// CHECK-NEXT: | [sizeof=24, dsize=20, align=8,
// CHECK-NEXT: | nvsize=16, nvalign=8]
struct D : virtual V {
[[no_unique_address]] B b;
};
static_assert(sizeof(D) == 24);
// CHECK:*** Dumping AST Record Layout
// CHECK: 0 | struct NVSizeGreaterThanDSize::D
// CHECK-NEXT: 0 | (D vtable pointer)
// CHECK-NEXT: 8 | struct NVSizeGreaterThanDSize::B b
// CHECK-NEXT: 8 | struct NVSizeGreaterThanDSize::A (base) (empty)
// CHECK-NEXT: 8 | char c
// CHECK-NEXT: 16 | struct NVSizeGreaterThanDSize::V (virtual base)
// CHECK-NEXT: 16 | int n
// CHECK-NEXT: | [sizeof=24, dsize=20, align=8,
// CHECK-NEXT: | nvsize=16, nvalign=8]
struct X : virtual A { [[no_unique_address]] A a; };
struct E : virtual A {
[[no_unique_address]] A a;
// Here, we arrange for X to hang over the end of the nvsize of E. This
// should force the A vbase to be laid out at offset 24, not 16.
[[no_unique_address]] X x;
};
static_assert(sizeof(E) == 32);
// CHECK:*** Dumping AST Record Layout
// CHECK: 0 | struct NVSizeGreaterThanDSize::E
// CHECK-NEXT: 0 | (E vtable pointer)
// CHECK-NEXT: 0 | struct NVSizeGreaterThanDSize::A a (empty)
// CHECK-NEXT: 8 | struct NVSizeGreaterThanDSize::X x
// CHECK-NEXT: 8 | (X vtable pointer)
// CHECK-NEXT: 8 | struct NVSizeGreaterThanDSize::A a (empty)
// CHECK-NEXT: 16 | struct NVSizeGreaterThanDSize::A (virtual base) (empty)
// CHECK-NEXT: 24 | struct NVSizeGreaterThanDSize::A (virtual base) (empty)
// CHECK-NEXT: | [sizeof=32, dsize=16, align=8,
// CHECK-NEXT: | nvsize=16, nvalign=8]
}
namespace RepeatedVBase {
struct alignas(16) A { ~A(); };
struct B : A {};
struct X : virtual A, virtual B {};
struct Y { [[no_unique_address]] X x; char c; };
static_assert(sizeof(Y) == 32);
// CHECK:*** Dumping AST Record Layout
// CHECK: 0 | struct RepeatedVBase::Y
// CHECK-NEXT: 0 | struct RepeatedVBase::X x
// CHECK-NEXT: 0 | (X vtable pointer)
// CHECK-NEXT: 0 | struct RepeatedVBase::A (virtual base) (empty)
// CHECK-NEXT: 16 | struct RepeatedVBase::B (virtual base) (empty)
// CHECK-NEXT: 16 | struct RepeatedVBase::A (base) (empty)
// CHECK-NEXT: 8 | char c
// CHECK-NEXT: | [sizeof=32, dsize=9, align=16,
// CHECK-NEXT: | nvsize=9, nvalign=16]
}