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

[Bill Wendling]

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>_______________________________________________
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