Add a new attribute, fortify_stdlib

This attribute applies to declarations of C stdlib functions
(sprintf, memcpy...) that have known fortified variants
(__sprintf_chk, __memcpy_chk, ...). When applied, clang will emit
calls to the fortified variant functions instead of calls to the
defaults.

In GCC, this is done by adding gnu_inline-style wrapper functions,
but that doesn't work for us for variadic functions because we don't
support __builtin_va_arg_pack (and have no intention to).

This attribute takes two arguments, the first is 'type' argument
passed through to __builtin_object_size, and the second is a flag
argument that gets passed through to the variadic checking variants.

rdar://47905754

Differential revision: https://reviews.llvm.org/D57918

llvm-svn: 353765

1 files changed, 4 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index 027ab0d6a20..9452de899fb 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -3697,6 +3697,10 @@ public:
   RValue EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
                          const CallExpr *E, ReturnValueSlot ReturnValue);
 
+  RValue emitFortifiedStdLibCall(CodeGenFunction &CGF, const CallExpr *CE,
+                                 unsigned BuiltinID, unsigned BOSType,
+                                 unsigned Flag);
+
   RValue emitRotate(const CallExpr *E, bool IsRotateRight);
 
   /// Emit IR for __builtin_os_log_format.