[libcxxabi] r302981 - [libcxxabi] Do not align field unwindHeader when building for ARM EHABI.
Akira Hatanaka via cfe-commits
cfe-commits at lists.llvm.org
Fri May 12 23:28:18 PDT 2017
Author: ahatanak
Date: Sat May 13 01:28:17 2017
New Revision: 302981
URL: http://llvm.org/viewvc/llvm-project?rev=302981&view=rev
Log:
[libcxxabi] Do not align field unwindHeader when building for ARM EHABI.
For ARM EHABI, _Unwind_Exception is an alias of _Unwind_Control_Block,
which is not aligned, so we shouldn't align unwindHeader either.
rdar://problem/25364625
Modified:
libcxxabi/trunk/src/cxa_exception.hpp
Modified: libcxxabi/trunk/src/cxa_exception.hpp
URL: http://llvm.org/viewvc/llvm-project/libcxxabi/trunk/src/cxa_exception.hpp?rev=302981&r1=302980&r2=302981&view=diff
==============================================================================
--- libcxxabi/trunk/src/cxa_exception.hpp (original)
+++ libcxxabi/trunk/src/cxa_exception.hpp Sat May 13 01:28:17 2017
@@ -64,10 +64,18 @@ struct _LIBCXXABI_HIDDEN __cxa_exception
// This field is annotated with attribute aligned so that the exception
// object following the field is sufficiently aligned and there is no
// gap between the field and the exception object. r276215 made a change to
- // annotate _Unwind_Exception with __attribute__((aligned)), but we cannot
- // incorporate the fix on Darwin since it is an ABI-breaking change, which
- // is why we need the attribute on this field.
+ // annotate _Unwind_Exception in unwind.h with __attribute__((aligned)), but
+ // we cannot incorporate the fix on Darwin since it is an ABI-breaking
+ // change, which is why we need the attribute on this field.
+ //
+ // For ARM EHABI, we do not align this field since _Unwind_Exception is an
+ // alias of _Unwind_Control_Block, which is not annotated with
+ // __attribute__((aligned).
+#if defined(_LIBCXXABI_ARM_EHABI)
+ _Unwind_Exception unwindHeader;
+#else
_Unwind_Exception unwindHeader __attribute__((aligned));
+#endif
};
// http://sourcery.mentor.com/archives/cxx-abi-dev/msg01924.html
@@ -104,7 +112,11 @@ struct _LIBCXXABI_HIDDEN __cxa_dependent
// See the comment in __cxa_exception as to why this field has attribute
// aligned.
+#if defined(_LIBCXXABI_ARM_EHABI)
+ _Unwind_Exception unwindHeader;
+#else
_Unwind_Exception unwindHeader __attribute__((aligned));
+#endif
};
struct _LIBCXXABI_HIDDEN __cxa_eh_globals {
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