Fix exception address alignment test for EHABI

This test fails on ARM bare-metal targets because it assumes the Itanium ABI,
whereas EHABI requires the exception address to be 8-byte aligned.

I was a bit puzzled at first because this should've failed on the public
arm-linux builder too. I think the reason it passes there is because we don't
include libunwind headers in the include path when running the libcxxabi tests,
so the system unwind.h gets picked up.

Reviewers: rengolin, EricWF
Differential revision: https://reviews.llvm.org/D31178

git-svn-id: https://llvm.org/svn/llvm-project/libcxxabi/trunk@299435 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 21 insertions, 4 deletions

diff --git a/test/libcxxabi/test/config.py b/test/libcxxabi/test/config.py
index 6d4da90..75da244 100644
--- a/test/libcxxabi/test/config.py
+++ b/test/libcxxabi/test/config.py
@@ -84,6 +84,13 @@ class Configuration(LibcxxConfiguration):
                                   % libcxxabi_headers)
         self.cxx.compile_flags += ['-I' + libcxxabi_headers]
 
+        libunwind_headers = self.get_lit_conf('libunwind_headers', None)
+        if self.get_lit_bool('llvm_unwinder', False) and libunwind_headers:
+            if not os.path.isdir(libunwind_headers):
+                self.lit_config.fatal("libunwind_headers='%s' is not a directory."
+                                      % libunwind_headers)
+            self.cxx.compile_flags += ['-I' + libunwind_headers]
+
     def configure_compile_flags_exceptions(self):
         pass
 
diff --git a/test/lit.site.cfg.in b/test/lit.site.cfg.in
index a650660..faa8df9 100644
--- a/test/lit.site.cfg.in
+++ b/test/lit.site.cfg.in
@@ -6,6 +6,7 @@ config.libcxxabi_obj_root       = "@LIBCXXABI_BINARY_DIR@"
 config.abi_library_path         = "@LIBCXXABI_LIBRARY_DIR@"
 config.libcxx_src_root          = "@LIBCXXABI_LIBCXX_PATH@"
 config.cxx_headers              = "@LIBCXXABI_LIBCXX_INCLUDES@"
+config.libunwind_headers        = "@LIBCXXABI_LIBUNWIND_INCLUDES_INTERNAL@"
 config.cxx_library_root         = "@LIBCXXABI_LIBCXX_LIBRARY_PATH@"
 config.llvm_unwinder            = "@LIBCXXABI_USE_LLVM_UNWINDER@"
 config.enable_threads           = "@LIBCXXABI_ENABLE_THREADS@"
diff --git a/test/test_exception_address_alignment.pass.cpp b/test/test_exception_address_alignment.pass.cpp
index 8a41f0c..138fb4d 100644
--- a/test/test_exception_address_alignment.pass.cpp
+++ b/test/test_exception_address_alignment.pass.cpp
@@ -15,8 +15,8 @@
 // working around this failure.
 // XFAIL: darwin && libcxxabi-has-system-unwinder
 
-// Test that the address of the exception object is properly aligned to the
-// largest supported alignment for the system.
+// Test that the address of the exception object is properly aligned as required
+// by the relevant ABI
 
 #include <cstdint>
 #include <cassert>
@@ -24,7 +24,16 @@
 #include <unwind.h>
 
 struct __attribute__((aligned)) AlignedType {};
-static_assert(alignof(AlignedType) == alignof(_Unwind_Exception),
+
+// EHABI  : 8-byte aligned
+// Itanium: Largest supported alignment for the system
+#if defined(_LIBUNWIND_ARM_EHABI)
+#  define EXPECTED_ALIGNMENT 8
+#else
+#  define EXPECTED_ALIGNMENT alignof(AlignedType)
+#endif
+
+static_assert(alignof(_Unwind_Exception) == EXPECTED_ALIGNMENT,
   "_Unwind_Exception is incorrectly aligned. This test is expected to fail");
 
 struct MinAligned {  };
@@ -35,7 +44,7 @@ int main() {
     try {
       throw MinAligned{};
     } catch (MinAligned const& ref) {
-      assert(reinterpret_cast<uintptr_t>(&ref) % alignof(AlignedType) == 0);
+      assert(reinterpret_cast<uintptr_t>(&ref) % EXPECTED_ALIGNMENT == 0);
     }
   }
 }