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Re: [patch ping] C6X unwinding/exception handling
- From: Paul Brook <paul at codesourcery dot com>
- To: libstdc++ at gcc dot gnu dot org
- Date: Thu, 1 Sep 2011 12:07:27 +0100
- Subject: Re: [patch ping] C6X unwinding/exception handling
- References: <email@example.com>
Ping for libstdc++ bits?
(Tested on arm-linux-gnueabi and c6x-elf, lightly tested on i686-linux)
> C6X uses an unwinding/exception handling echeme very similar to that
> defined by the ARM EABI. The core of the unwinder is the same, so I've
> pulled it out into a common file.
> Other than the obvious target specific bits, the main compiler visible
> difference is that the C6X assembler generates the unwinding tables from
> DWARF .cfi directives, rather than the separate set of directives used by
> the ARM assembler.
> The libstdc++ changes probably deserve a bit of explanation. The ttype_base
> field was clearly used in an early draft of the ARM EABI, and the current
> ARM definition is a compatible subset of that used by C6X.
> _GLIBCXX_OVERRIDE_TTYPE_ENCODING is an unfortunate hack because when doing
> the ARM implementation I failed to realise ttype_encoding was the same
> thing as R_ARM_TARGET2. We now have a lot of ARM binaries floating around
> with that field set incorrectly, so it's either this or an ABI bump.
> 2011-08-04 Paul Brook <firstname.lastname@example.org>
> * libsupc++/eh_arm.cc (__cxa_end_cleanup): Add C6X implementation.
> * libsupc++/eh_call.cc (__cxa_call_unexpected): Set rtti_base.
> * libsupc++/eh_personality.cc (NO_SIZE_OF_ENCODED_VALUE): Remove
> __ARM_EABI_UNWINDER__ check.
> (parse_lsda_header): Check _GLIBCXX_OVERRIDE_TTYPE_ENCODING.
> (get_ttype_entry): Use generic implementation on ARM EABI.
> (check_exception_spec): Use _Unwind_decode_typeinfo_ptr and
> (PERSONALITY_FUNCTION): Set ttype_base. Use UNWIND_STACK_REG and