Automatic Reference Counting.

Language-design credit goes to a lot of people, but I particularly want
to single out Blaine Garst and Patrick Beard for their contributions.

Compiler implementation credit goes to Argyrios, Doug, Fariborz, and myself,
in no particular order.

llvm-svn: 133103

1 files changed, 14 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/TargetInfo.h b/clang/lib/CodeGen/TargetInfo.h
index 4f59eb619e9..dbb09b1614d 100644
--- a/clang/lib/CodeGen/TargetInfo.h
+++ b/clang/lib/CodeGen/TargetInfo.h
@@ -111,6 +111,20 @@ namespace clang {
                                                   const llvm::Type* Ty) const {
       return Ty;
     }
+
+    /// Retrieve the address of a function to call immediately before
+    /// calling objc_retainAutoreleasedReturnValue.  The
+    /// implementation of objc_autoreleaseReturnValue sniffs the
+    /// instruction stream following its return address to decide
+    /// whether it's a call to objc_retainAutoreleasedReturnValue.
+    /// This can be prohibitively expensive, depending on the
+    /// relocation model, and so on some targets it instead sniffs for
+    /// a particular instruction sequence.  This functions returns
+    /// that instruction sequence in inline assembly, which will be
+    /// empty if none is required.
+    virtual llvm::StringRef getARCRetainAutoreleasedReturnValueMarker() const {
+      return "";
+    }
   };
 }