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Re: [PATCH][nvptx] Ignore c++ exceptions


On Thu, Aug 02, 2018 at 05:30:53PM +0200, Tom de Vries wrote:
> The nvptx port can't support exceptions using sjlj, because ptx does not
> support sjlj.  However, default_except_unwind_info still returns UI_SJLJ, even
> even if we configure with --disable-sjlj-exceptions, because UI_SJLJ is the
> fallback option.
> 
> The reason default_except_unwind_info doesn't return UI_DWARF2 is because
> DWARF2_UNWIND_INFO is not defined in defaults.h, because
> INCOMING_RETURN_ADDR_RTX is not defined, because there's no ptx equivalent.
> 
> Testcase libgomp.c++/for-15.C currently doesn't compile unless fno-exceptions
> is added because:
> - it tries to generate sjlj exception handling code, and
> - it tries to generate exception tables using label-addressed .byte sequence.
>   Ptx doesn't support generating random data at a label, nor being able to
>   load/write data relative to a label.
> 
> This patch fixes the first problem by using UI_TARGET for nvptx.
> 
> The second problem is worked around by generating all .byte sequences commented
> out.  It would be better to have a narrower workaround, and define
> TARGET_ASM_BYTE_OP to "error: .byte unsupported " or some such.

Hopefully this part is temporary and there is some way to figure this out
later.

> This patch does not enable exceptions for nvptx, it merely allows c++ programs
> to run correctly if they do no use exception handling.
> 
> Build on x86_64 with nvptx accelerator and reg-tested libgomp.
> 
> OK for trunk?

You are the nvptx maintainer, so you can approve the changes yourself.
The libgomp changes are ok.

> [nvptx] Ignore c++ exceptions
> 
> 2018-08-02  Tom de Vries  <tdevries@suse.de>
> 
> 	PR target/86660
> 	* common/config/nvptx/nvptx-common.c (nvptx_except_unwind_info): New
> 	function.  Return UI_TARGET unconditionally.
> 	(TARGET_EXCEPT_UNWIND_INFO): Redefine to nvptx_except_unwind_info.
> 	* config/nvptx/nvptx.c (TARGET_ASM_BYTE_OP): Emit commented out '.byte'.
> 
> 	* testsuite/libgomp.oacc-c++/routine-1-auto.C: Remove -fno-exceptions.
> 	* testsuite/libgomp.oacc-c++/routine-1-template-auto.C: Same.
> 	* testsuite/libgomp.oacc-c++/routine-1-template-trailing-return-type.C:
> 	Same.
> 	* testsuite/libgomp.oacc-c++/routine-1-template.C: Same.
> 	* testsuite/libgomp.oacc-c++/routine-1-trailing-return-type.C: Same.
> 	* testsuite/libgomp.oacc-c-c++-common/routine-1.c: Same.

	Jakub


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