Recent improvements to null address warnings notice that for
targets that do not support HAVE_ELF_STYLE_WEAKREF the dummy stub
implementation of __cxa_get_globals() means that the address can
never be null.

Fixed by removing the test for such targets.

Signed-off-by: Iain Sandoe <iain@sandoe.co.uk>

libitm/ChangeLog:

	* eh_cpp.cc (GTM::gtm_thread::init_cpp_exceptions): If the
	target does not support HAVE_ELF_STYLE_WEAKREF then do not
	try to test the __cxa_get_globals against NULL.

I discovered that libitm:
(a) declares __cxa_allocate_exception and friends directly,
(b) doesn't mark them as 'throw()'
(c) doesn't mark the replacment fns _ITM_$foo as nothrow either

We happen to get away with it because of code in the compiler that,
although it checks the parameter types, doesn't check the exception
specification.  (One reason being they used to not be part of the
language's type system, but now they are.)  I suspect this can lead us
to generate pessimal code later, if we've seen one of these decls
earlier.  Anyway, with modules it becomes trickier[*], so I'm trying
to clean it up and not be a problem.  I see Jakub fixed part of the
problem
(https://gcc.gnu.org/pipermail/gcc-patches/2018-December/513302.html)
AFAICT, he did fix libitm's decls, but left the lax parm-type checking
in the compiler.

libitm.h is not very informative about specification:
  in version 1 of http://www.intel.com/some/path/here.pdf.  */

Anyway, it was too fiddly to have libitm pick up the declarations from
libsupc++.  Besides it makes them weak declarations, and then provides
definitions for non-elf systems.  So this patch adds the expected
'throw()'

	* libitm/libitm.h (_ITM_NOTHROW): Define.
	(_ITM_cxa_allocate_exception, _ITM_cxa_free_exception)
	(_ITM_cxa_begin_catch): Use it.
	* eh_cpp.cc: Add throw() to __cxa_allocate_exception,
	__cxa_free_exception, __cxa_begin_catch, __cxa_tm_cleanup,
	__cxa_get_globals.
	(_ITM_cxa_allocate_exception, _ITM_cxa_free_exception)
	(_ITM_cxa_begin_catch): Likewise.

From-SVN: r279813

From-SVN: r267494

	PR c++/88482
	* except.c (verify_library_fn): New function.
	(declare_library_fn): Use it.  Initialize TM even if the non-TM
	library function has been user declared.
	(do_end_catch): Don't set TREE_NOTHROW on error_mark_node.
	(expand_start_catch_block): Don't call initialize_handler_parm
	for error_mark_node.
	(build_throw): Use verify_library_fn.  Initialize TM even if the
	non-TM library function has been user declared.  Don't crash if
	any library fn is error_mark_node.

	* g++.dg/eh/builtin5.C: New test.
	* g++.dg/eh/builtin6.C: New test.
	* g++.dg/eh/builtin7.C: New test.
	* g++.dg/eh/builtin8.C: New test.
	* g++.dg/eh/builtin9.C: New test.
	* g++.dg/eh/builtin10.C: New test.
	* g++.dg/eh/builtin11.C: New test.
	* g++.dg/parse/crash55.C: Adjust expected diagnostics.

	* eh_cpp.cc (__cxa_throw): Change DEST argument type from
	void * to void (*) (void *).
	(_ITM_cxa_throw): Likewise.
	* libitm.h (_ITM_cxa_throw): Likewise.
	* libitm.texi (_ITM_cxa_throw): Likewise.

From-SVN: r267179