Add NamedDecl::getUnderlyingDecl that can see through UsingDecl and ObjCCompatibleAliasDecl.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@74279 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 13 insertions, 0 deletions

diff --git a/lib/AST/Decl.cpp b/lib/AST/Decl.cpp
index 4fbf2f6f48..5382ab52ab 100644
--- a/lib/AST/Decl.cpp
+++ b/lib/AST/Decl.cpp
@@ -297,6 +297,19 @@ bool NamedDecl::hasLinkage() const {
   return false;
 }
 
+NamedDecl *NamedDecl::getUnderlyingDecl() {
+  NamedDecl *ND = this;
+  while (true) {
+    if (UsingDecl *UD = dyn_cast<UsingDecl>(ND))
+      ND = UD->getTargetDecl();
+    else if (ObjCCompatibleAliasDecl *AD
+              = dyn_cast<ObjCCompatibleAliasDecl>(ND))
+      return AD->getClassInterface();
+    else
+      return ND;
+  }
+}
+
 //===----------------------------------------------------------------------===//
 // VarDecl Implementation
 //===----------------------------------------------------------------------===//