[PATCH] libcxxabi/unwind: Add support for ARM EHABI in AddressSpace.hpp

[Jonathan Roelofs]

Nick,

This combines with Logan's work, and implements the libunwind bits that Logan's 
patch relied on libgcc_s for, in order to get rid of that dependency.

Jon

On 6/3/14, 3:47 PM, Nick Kledzik wrote:
> Dana,
>
> Is this a separate implementation of ARM EHABI than what Logan proposed
> 4/13/2014?  Or is this this same, but broken into steps?
>
>
>
>> +  }
>> +  #define _LIBUNWIND_BUILD_ZERO_COST_APIS (__i386__ || __x86_64__ ||
>> __arm64__ || __arm__)
>> +  #define _LIBUNWIND_BUILD_SJLJ_APIS      0
>> +  #define _LIBUNWIND_SUPPORT_FRAME_APIS   (__i386__ || __x86_64__)
>> +  #define _LIBUNWIND_EXPORT               __attribute__((visibility("default")))
>> +  #define _LIBUNWIND_HIDDEN               __attribute__((visibility("hidden")))
>> +  #define _LIBUNWIND_LOG(msg, ...) fprintf(stderr, "libuwind: " msg, __VA_ARGS__)
>> +  #define _LIBUNWIND_ABORT(msg) assert_rtn(__func__, __FILE__, __LINE__, msg)
>> +
>> +  #define _LIBUNWIND_SUPPORT_COMPACT_UNWIND   0
>> +  #define _LIBUNWIND_SUPPORT_DWARF_UNWIND     0
>> +  #define _LIBUNWIND_SUPPORT_DWARF_INDEX      0
>> +  #define _LIBUNWIND_SUPPORT_ARM_EHABI_UNWIND 1
>>  #endif
> There will be three unwinding models: zero-cost, sj-lj, and EHABI.  So there
> should be three mutually exclusive build settings:
>    _LIBUNWIND_BUILD_ZERO_COST_APIS
>    _LIBUNWIND_BUILD_SJLJ_APIS
>    _LIBUNWIND_BUILD_ARM_EHABI_APIS
>
> The SUPPORT_{COMPACT_UNWIND,DWARF_UNWIND,DWARF_INDEX} were intended as ways that
> zero-cost unwind information could be encoded.
>
> The patch above turns on both _LIBUNWIND_BUILD_ZERO_COST_APIS for all
> architectures, which is wrong.  It also leaves _LIBUNWIND_BUILD_ZERO_COST_APIS
> true for __arm__ which is probably wrong too.
>
> -Nick
>
>
> On Jun 2, 2014, at 5:48 AM, Dana Jansens <danakj at google.com
> <mailto:danakj at google.com>> wrote:
>> Hi Nick,
>>
>> Can you please take a look at this patch? With this, we define an
>> UnwindInfoSections for ARM EHABI and are able to populate it.
>>
>> We'll start making use of this in future patches, as Albert laid out here:
>> http://lists.cs.uiuc.edu/pipermail/cfe-commits/Week-of-Mon-20140526/106670.html
>>
>> This patch builds and passes tests on Mac.
>>
>> Thanks,
>> Dana
>> <ehabi_address_space.diff>
>

-- 
Jon Roelofs
jonathan at codesourcery.com
CodeSourcery / Mentor Embedded