[llvm-commits] [PATCH] -fstack-protector-strong parts 1 and 2

[Bill Wendling]

Patches applied. Thanks, Josh!

-bw

On Jan 22, 2013, at 7:33 PM, "Magee, Josh" <Joshua.Magee at am.sony.com> wrote:

> Hi Bill, thank for you reviewing.
> 
> I made the alphabetization changes for patch 1.
> 
> I also updated part 2.  I discovered that it was possible for the analysis of
> PHI nodes to get stuck in infinite recursion.  This could happen in loops where
> a subsequent use of the PHI node was also an incoming value to the node.  The
> fix for this is to keep track of the PHI nodes as they are analyzed and skip those
> that have already been seen.
> 
> Additionally, I changed a few places where I was redundantly iterating through
> all the operands of a use.  For example, in the case of the CallInst, I already
> know that the CallInst is a use of AI so it isn't necessary to iterate over
> every operand just to check for AI.  In this case the previous code wasn't
> incorrect, but it was inefficient/unnecessary.
> 
> I don't have commit access, so I'd be very happy if you could apply for me
> (assuming the updated patches are okay, of course.)
> 
> Thanks,
> - Josh
> 
> 
> 
> ________________________________________
> From: Bill Wendling [wendling at apple.com]
> Sent: 18 January 2013 16:51
> To: Magee, Josh
> Cc: llvm-commits at cs.uiuc.edu
> Subject: Re: [llvm-commits] [PATCH] -fstack-protector-strong parts 1 and 2
> 
> Hi Josh,
> 
> Part II also looks fine to me. Go ahead and apply if you want. :)
> 
> -bw
> 
> On Jan 14, 2013, at 7:36 PM, "Magee, Josh" <Joshua.Magee at am.sony.com> wrote:
> 
>> Ping - with updated patches.
>> 
>> Part 1 is an updated version of my previously attached patch, which adds the IR attribute  'sspstrong'.
>> I could see that this patch by itself may not be that interesting or helpful in seeing where this feature is going, so attached the second patch as well.  Part 2 implements the strong heuristic itself.
>> The requirements of the strong heuristic are:
>> * A Protector is required for functions which contain an array, regardless of type or length.
>> * A Protector is required for functions which contain a structure/union which
>> contains an array, regardless of type or length.  Note, there is no limit to the depth of nesting.
>> * A protector is required when the address of a local variable (i.e., stack based variable) is exposed.  (E.g., such as through a local whose address is taken as part of the RHS of an assignment or a local whose address is taken as part of a function argument.)
>> 
>> One of the requirements for standard SSP mode (-fstack-protector) was not fully met, so it needed to be tweaked.
>> The requirements for the standard heuristic are:
>> * Protector is required for a functions which contain a call to alloca with a variable size or constant size greater than ssp-buffer-size (default 8).
>> The existing implementation would enable protectors for all calls to alloca.
>> 
>> Please ask questions / make comments.
>> 
>> The remaining patches are:
>> Part 3 - Data layout Rules (Implements stricter data layout rules to place SSP-triggering variables closer to the protector)
>> Part 4 - Clang Command line options
>> Part 5 - Clang Attributes
>> 
>> In the spirit of delivering in small increments, I would prefer to get the current patches reviewed before sending additional ones. :-)
>> 
>> 
>> Thanks,
>> Josh
>> 
>> 
>> ________________________________________
>> From: llvm-commits-bounces at cs.uiuc.edu [llvm-commits-bounces at cs.uiuc.edu] on behalf of Magee, Josh [Joshua.Magee at am.sony.com]
>> Sent: 21 November 2012 17:50
>> To: llvm-commits at cs.uiuc.edu
>> Subject: [llvm-commits] [PATCH] -fstack-protector-strong part 1: sspstrong      IR attribute
>> 
>> Hi,
>> 
>> This is the first patch for an implementation of ssp-strong previously
>> proposed to llvm-dev:
>> http://lists.cs.uiuc.edu/pipermail/llvmdev/2012-October/053931.html
>> 
>> This patch adds the IR attribute 'sspstrong'.  For now, sspstrong is treated
>> identically to sspreq.  The actual "strong" heuristic will be provided in a
>> subsequent patch.
>> 
>> Rather than updating the documentation at the end, I plan to keep it in sync
>> with each patch.  For now it lists 'sspstrong' as being equivalent to 'sspreq',
>> but once the heuristic is in place then the docs will be updated accordingly.
>> (If preferred the documentation could be provided at the end, but I thought
>> delivering it incrementally along with the code would be better.)
>> 
>> Thanks,
>> Josh
>> <part1-sspstrong-ir-attribute.diff><part2-sspstrong-heuristic.diff>_______________________________________________
>> llvm-commits mailing list
>> llvm-commits at cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
> 
> 
> <part1-sspstrong-ir-attribute-0122.diff><part2-sspstrong-heuristic-0122.diff>