xref: /llvm-project/libcxxabi/test/test_exception_address_alignment.pass.cpp (revision c360553c15a8e5aa94d2236eb73e7dfeab9543e5)
1 //===----------------------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 // UNSUPPORTED: no-exceptions
10 // UNSUPPORTED: c++03
11 
12 // The <unwind.h> header provided in the SDK of older Xcodes used to provide
13 // an incorrectly aligned _Unwind_Exception type on non-ARM. That causes these
14 // tests to fail when compiling against such a SDK, or when running against a
15 // system libc++abi that was compiled with an incorrect definition of _Unwind_Exception.
16 // XFAIL: apple-clang-12.0.0 && !target={{arm.*}}
17 // XFAIL: apple-clang-11 && !target={{arm.*}}
18 // XFAIL: apple-clang-10 && !target={{arm.*}}
19 // XFAIL: apple-clang-9 && !target={{arm.*}}
20 // XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12}}
21 
22 // Test that the address of the exception object is properly aligned as required
23 // by the relevant ABI
24 
25 #include <cstdint>
26 #include <cassert>
27 #include <__cxxabi_config.h>
28 
29 #include <unwind.h>
30 
31 struct __attribute__((aligned)) AlignedType {};
32 
33 // EHABI  : 8-byte aligned
34 // Itanium: Largest supported alignment for the system
35 #if defined(_LIBCXXABI_ARM_EHABI)
36 #  define EXPECTED_ALIGNMENT 8
37 #else
38 #  define EXPECTED_ALIGNMENT alignof(AlignedType)
39 #endif
40 
41 static_assert(alignof(_Unwind_Exception) == EXPECTED_ALIGNMENT,
42   "_Unwind_Exception is incorrectly aligned. This test is expected to fail");
43 
44 struct MinAligned {  };
45 static_assert(alignof(MinAligned) == 1 && sizeof(MinAligned) == 1, "");
46 
47 int main(int, char**) {
48   for (int i=0; i < 10; ++i) {
49     try {
50       throw MinAligned{};
51     } catch (MinAligned const& ref) {
52       assert(reinterpret_cast<uintptr_t>(&ref) % EXPECTED_ALIGNMENT == 0);
53     }
54   }
55 
56   return 0;
57 }
58