mirror of
https://github.com/llvm/llvm-project.git
synced 2025-05-01 12:46:09 +00:00
aee4925507
Based on post-commit review discussion on 2bd84938470bf2e337801faafb8a67710f46429d with Richard Smith. Other uses of forcing HasEmptyPlaceHolder to false seem OK to me - they're all around pointer/reference types where the pointer/reference token will appear at the rightmost side of the left side of the type name, so they make nested types (eg: the "int" in "int *") behave as though there is a non-empty placeholder (because the "*" is essentially the placeholder as far as the "int" is concerned). This was originally committed in 277623f4d5a672d707390e2c3eaf30a9eb4b075c Reverted in f9ad1d1c775a8e264bebc15d75e0c6e5c20eefc7 due to breakages outside of clang - lldb seems to have some strange/strong dependence on "char [N]" versus "char[N]" when printing strings (not due to that name appearing in DWARF, but probably due to using clang to stringify type names) that'll need to be addressed, plus a few other odds and ends in other subprojects (clang-tools-extra, compiler-rt, etc).
48 lines
1.8 KiB
C++
48 lines
1.8 KiB
C++
// RUN: %clang_cc1 -fsyntax-only -triple armv7k-apple-darwin-watchos -fdump-record-layouts %s | FileCheck %s
|
|
|
|
// WatchOS, 64-bit iOS, and WebAssembly use the C++11 definition of POD to
|
|
// determine whether we can reuse the tail padding of a struct (POD is
|
|
// "trivially copyable and standard layout"). The definition of standard
|
|
// layout changed some time around C++17; check that we still use the old
|
|
// ABI rule.
|
|
|
|
// B is not standard-layout, but it was under C++11's rule, so we pack
|
|
// C::d into its tail padding anyway.
|
|
struct A { int : 0; };
|
|
struct B : A { int n; char c[3]; };
|
|
struct C : B { char d; };
|
|
int c = sizeof(C);
|
|
static_assert(!__is_standard_layout(B));
|
|
|
|
// CHECK:*** Dumping AST Record Layout
|
|
// CHECK: 0 | struct C
|
|
// CHECK-NEXT: 0 | struct B (base)
|
|
// CHECK-NEXT: 0 | struct A (base) (empty)
|
|
// CHECK-NEXT: 0:- | int
|
|
// CHECK-NEXT: 0 | int n
|
|
// CHECK-NEXT: 4 | char[3] c
|
|
// CHECK-NEXT: 8 | char d
|
|
// CHECK-NEXT: | [sizeof=12, dsize=9, align=4,
|
|
// CHECK-NEXT: | nvsize=9, nvalign=4]
|
|
|
|
// F is not standard-layout due to the repeated D base class, but it was under
|
|
// C++11's rule, so we pack G::d into its tail padding anyway.
|
|
struct D {};
|
|
struct E : D {};
|
|
struct F : D, E { int n; char c[3]; };
|
|
struct G : F { G(const G&); char d; };
|
|
int g = sizeof(G);
|
|
static_assert(!__is_standard_layout(F));
|
|
|
|
// CHECK:*** Dumping AST Record Layout
|
|
// CHECK: 0 | struct G
|
|
// CHECK-NEXT: 0 | struct F (base)
|
|
// CHECK-NEXT: 0 | struct D (base) (empty)
|
|
// CHECK-NEXT: 1 | struct E (base) (empty)
|
|
// CHECK-NEXT: 1 | struct D (base) (empty)
|
|
// CHECK-NEXT: 0 | int n
|
|
// CHECK-NEXT: 4 | char[3] c
|
|
// CHECK-NEXT: 8 | char d
|
|
// CHECK-NEXT: | [sizeof=12, dsize=9, align=4,
|
|
// CHECK-NEXT: | nvsize=9, nvalign=4]
|