release_33 branch patches

[Brad Smith]

On 06/09/13 6:00 PM, Tom Stellard wrote:
> On Fri, Aug 30, 2013 at 09:13:06AM -0400, Brad Smith wrote:
>> On 29/08/13 3:59 PM, Tom Stellard wrote:
>>> On Thu, Aug 29, 2013 at 12:00:59PM -0400, Brad Smith wrote:
>>>> Here are some patches I'd like to propose being merged to the 3.3 branch..
>>>>
>>>> For LLVM..
>>>>
>>>> r183533 | rafael | 2013-06-07 12:35:57 -0400 (Fri, 07 Jun 2013) | 12 lines
>>>>
>>>> Support OpenBSD's native frame protection conventions.
>>>>
>>>> OpenBSD's stack smashing protection differs slightly from other
>>>> platforms:
>>>>
>>>>    1. The smash handler function is "__stack_smash_handler(const char
>>>>       *funcname)" instead of "__stack_chk_fail(void)".
>>>>
>>>>    2. There's a hidden "long __guard_local" object that gets linked
>>>>       into each executable and DSO.
>>>>
>>>> Patch by Matthew Dempsky.
>>>>
>>>
>>> I think this patch will break ABI compatibility, since it adds a new
>>> private member to the StackProtector class, so I don't think we can
>>> merge it as is.  Does this patch only affect OpenBSD?  If so, then my
>>> feeling is that it is OK with the ABI fixes, approval from the code owner,
>>> and a volunteer who is willing to test the 3.3.1 release on OpenBSD.
>>
>> Yes, it only affects OpenBSD. I can test this.
>>
>>>> For Clang..
>>>>
>>>> r183295 | rafael | 2013-06-05 00:28:55 -0400 (Wed, 05 Jun 2013) | 3 lines
>>>>
>>>> Default to PIE and using stack protection on OpenBSD.
>>>>
>>>> Patch by Matthew Dempsky.
>>>>
>>>
>>> I think the addition of the new option in Options.td will break the ABI,
>>> also it seems to me like a new feature, so I'm not sure if this should
>>> go in.  It would be good if the code owner or someone else could explain
>>> exactly why this patch is important.
>>
>> I don't understand what you mean by breaking the ABI when it comes
>> to adding a command line parameter for the compiler driver. This
>> commit is coupled with the commit above fixing the stack protector
>> support. Anyway, the idea was for the point release to fix the
>> OpenBSD support so building from src didn't require patching to have
>> a proper working compiler.
>>
>
> Modifying tablegen files can break the ABI in cases where tablegen is
> generating public lookup tables, since the tables are usually sorted by
> name, so adding something new may insert an item into the middle of the
> table.  I'm not sure if this is what Options.td is used for though.
>
> I know that requiring a stable ABI for point releases is rather strict,
> but when stable releases were proposed a few people expressed their
> preference for a stable ABI and no one objected.  I think it is too late
> to change this policy for 3.3, but perhaps we could revisit it for 3.4.

Ok, then please just look at getting r182446 in.


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