libcxxabi/test/test_exception_address_alignment.pass.cpp

   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 running against a system libc++abi and libunwind that was
  15 // compiled with an incorrect definition of _Unwind_Exception.
  16 // XFAIL: stdlib=apple-libc++ && target={{.+}}-apple-macosx10.{{9|10|11|12}}
  17
  18 // Test that the address of the exception object is properly aligned as required
  19 // by the relevant ABI
  20
  21 #include <cstdint>
  22 #include <cassert>
  23 #include <__cxxabi_config.h>
  24
  25 #include <unwind.h>
  26
  27 struct __attribute__((aligned)) AlignedType {};
  28
  29 // EHABI  : 8-byte aligned
  30 // Itanium: Largest supported alignment for the system
  31 #if defined(_LIBCXXABI_ARM_EHABI)
  32 #  define EXPECTED_ALIGNMENT 8
  33 #else
  34 #  define EXPECTED_ALIGNMENT alignof(AlignedType)
  35 #endif
  36
  37 static_assert(alignof(_Unwind_Exception) == EXPECTED_ALIGNMENT,
  38   "_Unwind_Exception is incorrectly aligned. This test is expected to fail");
  39
  40 struct MinAligned {  };
  41 static_assert(alignof(MinAligned) == 1 && sizeof(MinAligned) == 1, "");
  42
  43 int main(int, char**) {
  44   for (int i=0; i < 10; ++i) {
  45     try {
  46       throw MinAligned{};
  47     } catch (MinAligned const& ref) {
  48       assert(reinterpret_cast<uintptr_t>(&ref) % EXPECTED_ALIGNMENT == 0);
  49     }
  50   }
  51
  52   return 0;
  53 }