PNaCl SJLJ EH: Fix handling of dependent exceptions

PNaCl SJLJ EH: Fix handling of dependent exceptions

Dereferencing xh->exceptionType isn't valid for dependent exceptions
(those thrown with std::rethrow_exception(), added in C++11), because
xh might point to inside a __cxa_dependent_exception, which, in
libsupc++, shares some but not all of the layout of __cxa_exception.

We must get exceptionType from
__get_exception_header_from_obj(__get_object_from_ue(ue_header))
rather than from __get_exception_header_from_ue(ue_header).

That is because __get_object_from_ue() checks for dependent exceptions
and returns the pointer associated with the original __cxa_exception.

BUG=https://code.google.com/p/nativeclient/issues/detail?id=3696
TEST=run_eh_throw_tests_sjlj_test (with extra test added)

Committed: https://gerrit.chromium.org/gerrit/gitweb?p=native_client/pnacl-gcc.git;a=commit;h=5744291

[Mark Seaborn, 2013-12-02 14:39:32]

Test to be added by: https://codereview.chromium.org/97593002/

[Derek Schuff, 2013-12-02 18:24:09]

lgtm

https://codereview.chromium.org/97603002/diff/30001/libstdc++-v3/libsupc++/eh...
File libstdc++-v3/libsupc++/eh_pnacl.cc (right):

https://codereview.chromium.org/97603002/diff/30001/libstdc++-v3/libsupc++/eh...
libstdc++-v3/libsupc++/eh_pnacl.cc:244: __get_exception_header_from_obj
(obj)->exceptionType;
add a comment here mentioning why this has to be done.

[Mark Seaborn, 2013-12-02 18:49:14]

https://codereview.chromium.org/97603002/diff/30001/libstdc++-v3/libsupc++/eh...
File libstdc++-v3/libsupc++/eh_pnacl.cc (right):

https://codereview.chromium.org/97603002/diff/30001/libstdc++-v3/libsupc++/eh...
libstdc++-v3/libsupc++/eh_pnacl.cc:244: __get_exception_header_from_obj
(obj)->exceptionType;
On 2013/12/02 18:24:09, Derek Schuff wrote:
> add a comment here mentioning why this has to be done.

Done.

[Mark Seaborn, 2013-12-02 19:03:18]

Committed patchset #4 manually as r5744291 (presubmit successful).