| // RUN: %clang_cc1 -fno-rtti -fms-extensions -triple aarch64-windows-msvc -fdump-record-layouts -fsyntax-only %s 2>/dev/null \ |
| // RUN: | FileCheck %s -check-prefix CHECK-ARM64 |
| // RUN: %clang_cc1 -fno-rtti -fms-extensions -triple arm64ec-windows-msvc -fdump-record-layouts -fsyntax-only %s 2>/dev/null \ |
| // RUN: | FileCheck %s -check-prefix CHECK-X64 |
| // RUN: %clang_cc1 -fno-rtti -fms-extensions -triple x86_64-windows-msvc -fdump-record-layouts -fsyntax-only %s 2>/dev/null \ |
| // RUN: | FileCheck %s -check-prefix CHECK-X64 |
| |
| // On Arm64 (but not Arm64EC or x64), MSVC reuses the tail padding of an |
| // over-aligned base class for a subsequent base class. This holds whether the |
| // over-alignment comes from the record itself or from one of its fields. |
| |
| struct alignas(16) Type { |
| long long a, b, c; |
| }; |
| struct Mid : Type {}; |
| struct Node { void *next; }; |
| |
| // The over-aligned base's tail padding is reused for the following base only on |
| // Arm64. |
| struct Derived : Mid, Node {}; |
| |
| int a = sizeof(Derived); |
| |
| // CHECK-ARM64-LABEL: 0 | struct Derived |
| // CHECK-ARM64-NEXT: 0 | struct Mid (base) |
| // CHECK-ARM64-NEXT: 0 | struct Type (base) |
| // CHECK-ARM64: 24 | struct Node (base) |
| // CHECK-ARM64-NEXT: 24 | void * next |
| // CHECK-ARM64-NEXT: | [sizeof=32, align=16, |
| // CHECK-ARM64-NEXT: | nvsize=32, nvalign=16] |
| |
| // CHECK-X64-LABEL: 0 | struct Derived |
| // CHECK-X64-NEXT: 0 | struct Mid (base) |
| // CHECK-X64-NEXT: 0 | struct Type (base) |
| // CHECK-X64: 32 | struct Node (base) |
| // CHECK-X64-NEXT: 32 | void * next |
| // CHECK-X64-NEXT: | [sizeof=48, align=16, |
| // CHECK-X64-NEXT: | nvsize=48, nvalign=16] |
| |
| // The over-alignment can also come from `alignas` on an individual field rather |
| // than from the record itself; the tail padding is reused the same way. |
| struct FieldOver { |
| alignas(16) long long a; |
| long long b, c; |
| }; |
| struct FieldMid : FieldOver {}; |
| struct FieldDerived : FieldMid, Node {}; |
| |
| int b = sizeof(FieldDerived); |
| |
| // CHECK-ARM64-LABEL: 0 | struct FieldDerived |
| // CHECK-ARM64-NEXT: 0 | struct FieldMid (base) |
| // CHECK-ARM64-NEXT: 0 | struct FieldOver (base) |
| // CHECK-ARM64: 24 | struct Node (base) |
| // CHECK-ARM64-NEXT: 24 | void * next |
| // CHECK-ARM64-NEXT: | [sizeof=32, align=16, |
| // CHECK-ARM64-NEXT: | nvsize=32, nvalign=16] |
| |
| // CHECK-X64-LABEL: 0 | struct FieldDerived |
| // CHECK-X64-NEXT: 0 | struct FieldMid (base) |
| // CHECK-X64-NEXT: 0 | struct FieldOver (base) |
| // CHECK-X64: 32 | struct Node (base) |
| // CHECK-X64-NEXT: 32 | void * next |
| // CHECK-X64-NEXT: | [sizeof=48, align=16, |
| // CHECK-X64-NEXT: | nvsize=48, nvalign=16] |
| |
| // Reusing tail padding must not affect placement of an over-aligned base that |
| // follows another base: padding is still inserted so it lands at its required |
| // alignment. |
| struct PadBefore : Node, Type {}; |
| |
| int c = sizeof(PadBefore); |
| |
| // CHECK-ARM64-LABEL: 0 | struct PadBefore |
| // CHECK-ARM64-NEXT: 0 | struct Node (base) |
| // CHECK-ARM64-NEXT: 0 | void * next |
| // CHECK-ARM64-NEXT: 16 | struct Type (base) |
| // CHECK-ARM64: | [sizeof=48, align=16, |
| |
| // CHECK-X64-LABEL: 0 | struct PadBefore |
| // CHECK-X64-NEXT: 0 | struct Node (base) |
| // CHECK-X64-NEXT: 0 | void * next |
| // CHECK-X64-NEXT: 16 | struct Type (base) |
| // CHECK-X64: | [sizeof=48, align=16, |
| |
| // Over-alignment applied directly to a bitfield via __declspec(align) raises |
| // the record's alignment (rather than its required alignment) and is immune to |
| // #pragma pack. The over-aligned base tail-padding reuse above does not apply |
| // to bitfields, so this is left unchanged by that transformation and is handled |
| // identically on every target. |
| #pragma pack(2) |
| struct BitfieldAlign { |
| __declspec(align(16)) long long a : 8; |
| }; |
| #pragma pack() |
| |
| int d = sizeof(BitfieldAlign); |
| |
| // CHECK-ARM64-LABEL: 0 | struct BitfieldAlign |
| // CHECK-ARM64-NEXT: 0:0-7 | long long a |
| // CHECK-ARM64-NEXT: | [sizeof=8, align=16, |
| // CHECK-ARM64-NEXT: | nvsize=8, nvalign=16] |
| |
| // CHECK-X64-LABEL: 0 | struct BitfieldAlign |
| // CHECK-X64-NEXT: 0:0-7 | long long a |
| // CHECK-X64-NEXT: | [sizeof=8, align=16, |
| // CHECK-X64-NEXT: | nvsize=8, nvalign=16] |
