Implement the stack protector stack accesses via intrinsics:

- stackprotector_prologue creates a stack object and stores the guard there.

- stackprotector_epilogue reads the stack guard from the stack position created
  by stackprotector_prologue.

- The PrologEpilogInserter was changed to make sure that the stack guard is
  first on the stack frame.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58791 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Intrinsics.td

@@ -165,6 +165,7 @@ def int_stacksave     : Intrinsic<[llvm_ptr_ty]>,
                         GCCBuiltin<"__builtin_stack_save">;
 def int_stackrestore  : Intrinsic<[llvm_void_ty, llvm_ptr_ty]>,
                         GCCBuiltin<"__builtin_stack_restore">;
+
 // IntrWriteArgMem is more pessimistic than strictly necessary for prefetch,
 // however it does conveniently prevent the prefetch from being reordered
 // with respect to nearby accesses to the same memory.
@@ -175,6 +176,10 @@ def int_pcmarker      : Intrinsic<[llvm_void_ty, llvm_i32_ty]>;
 
 def int_readcyclecounter : Intrinsic<[llvm_i64_ty]>;
 
+// Stack protector intrinsics.
+def int_stackprotector_prologue : Intrinsic<[llvm_void_ty, llvm_ptr_ty]>;
+def int_stackprotector_epilogue : Intrinsic<[llvm_ptr_ty]>;
+
 //===------------------- Standard C Library Intrinsics --------------------===//
 //