Commit 765e9c1d authored by Eric Fiselier's avatar Eric Fiselier
Browse files

Merging r276215: 

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r276215 | ericwf | 2016-07-20 17:56:42 -0600 (Wed, 20 Jul 2016) | 9 lines

[libunwind] Properly align _Unwind_Exception.

Summary: _Unwind_Exception is required to be double word aligned. Currently the struct is under aligned.

Reviewers: mclow.lists, compnerd, kledzik, emaste

Subscribers: emaste, cfe-commits

Differential Revision: https://reviews.llvm.org/D22543
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llvm-svn: 276462
parent e24755b5

libunwind/include/unwind.h

+6 −3
Original line number Diff line number Diff line
@@ -122,13 +122,16 @@ struct _Unwind_Exception { 
  uintptr_t private_1; // non-zero means forced unwind

  uintptr_t private_2; // holds sp that phase1 found for phase2 to use

#ifndef __LP64__

  // The gcc implementation of _Unwind_Exception used attribute mode on the

  // above fields which had the side effect of causing this whole struct to

  // The implementation of _Unwind_Exception uses an attribute mode on the

  // above fields which has the side effect of causing this whole struct to

  // round up to 32 bytes in size. To be more explicit, we add pad fields

  // added for binary compatibility.

  uint32_t reserved[3];

#endif

};

  // The Itanium ABI requires that _Unwind_Exception objects are "double-word

  // aligned".  GCC has interpreted this to mean "use the maximum useful

  // alignment for the target"; so do we.

} __attribute__((__aligned__));



typedef _Unwind_Reason_Code (*_Unwind_Stop_Fn)

    (int version,

libunwind/test/alignment.pass.cpp

0 → 100644
+21 −0
Original line number Diff line number Diff line 
// -*- C++ -*-

//===----------------------------------------------------------------------===//

//

//                     The LLVM Compiler Infrastructure

//

// This file is dual licensed under the MIT and the University of Illinois Open

// Source Licenses. See LICENSE.TXT for details.

//

//===----------------------------------------------------------------------===//



// The Itanium ABI requires that _Unwind_Exception objects are "double-word

// aligned".



#include <unwind.h>



struct MaxAligned {} __attribute__((aligned));

static_assert(alignof(_Unwind_Exception) == alignof(MaxAligned), "");



int main()

{

}