objc-arc: set nonlazybind attribute on objc_retain/

objc_release for performance for these most often
called APIs. // rdar://12040837

llvm-svn: 161448

1 files changed, 6 insertions, 2 deletions

diff --git a/clang/lib/CodeGen/CGObjC.cpp b/clang/lib/CodeGen/CGObjC.cpp
index d5f3eccf48f..4ac172d1cbb 100644
--- a/clang/lib/CodeGen/CGObjC.cpp
+++ b/clang/lib/CodeGen/CGObjC.cpp
@@ -1696,9 +1696,13 @@ static llvm::Constant *createARCRuntimeFunction(CodeGenModule &CGM,
   // If the target runtime doesn't naturally support ARC, emit weak
   // references to the runtime support library.  We don't really
   // permit this to fail, but we need a particular relocation style.
-  if (!CGM.getLangOpts().ObjCRuntime.hasARC())
-    if (llvm::Function *f = dyn_cast<llvm::Function>(fn))
+  if (llvm::Function *f = dyn_cast<llvm::Function>(fn)) {
+    if (!CGM.getLangOpts().ObjCRuntime.hasARC())
       f->setLinkage(llvm::Function::ExternalWeakLinkage);
+    // set nonlazybind attribute for these APIs for performance.
+    if (fnName == "objc_retain" || fnName  == "objc_release")
+      f->addFnAttr(llvm::Attribute::NonLazyBind);
+  }
 
   return fn;
 }