This did break libobjc and libjava on arm-linux-gnueabi.
libobjc now has an undefined reference to _Unwind_decode_target2, which can be
avoided with
--- libobjc/exception.c.orig 2011-07-21 15:33:57.000000000 +0000
+++ libobjc/exception.c 2011-10-09 10:53:12.554940776 +0000
@@ -182,7 +182,7 @@
_Unwind_Ptr ptr;
ptr = (_Unwind_Ptr) (info->TType - (i * 4));
- ptr = _Unwind_decode_target2 (ptr);
+ ptr = _Unwind_decode_typeinfo_ptr (info->ttype_base, (_Unwind_Word) ptr);
/* NULL ptr means catch-all. Note that if the class is not found,
this will abort the program. */
libjava fails to build, the same change doesn't work for libjava/exception.cc,
because the struct lsda_header_info in exception.cc is missing the ttype_base
member. Any suggestions?
On 09/13/2011 02:48 PM, Paul Brook wrote:
>> 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.
>
> I've updated the patch to accomodate the move to libgcc/, done a quick sanity
> recheck of arm-linux and c6x-elf and applied to svn.
>
> P.S. in case it's not clear from my description, the libstdc++ changes aren't
> really a new hack, it's just making an old one more obvious.
>
> Paul
>
> 2011-09-13 Paul Brook <p...@codesourcery.com>
>
> gcc/
> * config/arm/arm.h (ASM_PREFERRED_EH_DATA_FORMAT): Define.
> (ARM_TARGET2_DWARF_FORMAT): Provide default definition.
> * config/arm/linux-eabi.h (ARM_TARGET2_DWARF_FORMAT): Define.
> * config/arm/symbian.h (ARM_TARGET2_DWARF_FORMAT): Define.
> * config/arm/uclinux-eabi.h(ARM_TARGET2_DWARF_FORMAT): Define.
> * config/arm/t-bpabi (EXTRA_HEADERS): Add unwind-arm-common.h.
> * config/arm/t-symbian (EXTRA_HEADERS): Add unwind-arm-common.h.
> * config/c6x/c6x.c (c6x_output_file_unwind): Don't rely on dwarf2 code
> enabling unwind tables.
> (c6x_debug_unwind_info): New function.
> (TARGET_ARM_EABI_UNWINDER): Define.
> (TARGET_DEBUG_UNWIND_INFO): Define.
> * config/c6x/c6x.h (DWARF_FRAME_RETURN_COLUMN): Define.
> (TARGET_EXTRA_CFI_SECTION): Remove.
> * config/c6x/t-c6x-elf (EXTRA_HEADERS): Set.
> * ginclude/unwind-arm-common.h: New file.
>
> libgcc/
> * config.host (tic6x-*-*): Add c6x/t-c6x-elf. Set unwind_header.
> * unwind-c.c (PERSONALITY_FUNCTION): Use UNWIND_POINTER_REG.
> * unwind-arm-common.inc: New file.
> * config/arm/unwind-arm.c: Use unwind-arm-common.inc.
> * config/arm/unwind-arm.h: Use unwind-arm-common.h.
> (_GLIBCXX_OVERRIDE_TTYPE_ENCODING): Define.
> * config/c6x/libunwind.S: New file.
> * config/c6x/pr-support.c: New file.
> * config/c6x/unwind-c6x.c: New file.
> * config/c6x/unwind-c6x.h: New file.
> * config/c6x/t-c6x-elf: New file.
>
>
> libstdc++-v3/
> * 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
> UNWIND_STACK_REG.
> (PERSONALITY_FUNCTION): Set ttype_base.
