Add the IR attribute 'sspstrong'.

SSPStrong applies a heuristic to insert stack protectors in these situations:

* 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.)

This patch implements the SSPString attribute to be equivalent to
SSPRequired. This will change in a subsequent patch.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173230 91177308-0d34-0410-b5e6-96231b3b80d8

utils/vim/llvm.vim

@@ -51,10 +51,10 @@ syn keyword llvmKeyword noimplicitfloat noinline nonlazybind noredzone noreturn
 syn keyword llvmKeyword nounwind optsize personality private protected
 syn keyword llvmKeyword ptx_device ptx_kernel readnone readonly release
 syn keyword llvmKeyword returns_twice section seq_cst sideeffect signext
-syn keyword llvmKeyword singlethread spir_func spir_kernel sret ssp sspreq tail
-syn keyword llvmKeyword target thread_local to triple unnamed_addr unordered
-syn keyword llvmKeyword uwtable volatile weak weak_odr x86_fastcallcc
-syn keyword llvmKeyword x86_stdcallcc x86_thiscallcc zeroext
+syn keyword llvmKeyword singlethread spir_func spir_kernel sret ssp sspreq
+syn keyword llvmKeyword sspstrong tail target thread_local to triple
+syn keyword llvmKeyword unnamed_addr unordered uwtable volatile weak weak_odr
+syn keyword llvmKeyword x86_fastcallcc x86_stdcallcc x86_thiscallcc zeroext
 
 " Obsolete keywords.
 syn keyword llvmError  getresult begin end