Allow "overloadable" functions in C to be declared as variadic without

any named parameters, e.g., this is accepted in C:

  void f(...) __attribute__((overloadable));

although this would be rejected:

  void f(...);

To do this, moved the checking of the "ellipsis without any named
arguments" condition from the parser into Sema (where it belongs anyway).



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@64902 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 16 insertions, 0 deletions

diff --git a/lib/Sema/SemaType.cpp b/lib/Sema/SemaType.cpp
index e6aafdab08..a385a13f4c 100644
--- a/lib/Sema/SemaType.cpp
+++ b/lib/Sema/SemaType.cpp
@@ -474,6 +474,22 @@ QualType Sema::GetTypeForDeclarator(Declarator &D, Scope *S, unsigned Skip) {
           // C++ 8.3.5p2: If the parameter-declaration-clause is empty, the
           // function takes no arguments.
           T = Context.getFunctionType(T, NULL, 0, FTI.isVariadic,FTI.TypeQuals);
+        } else if (FTI.isVariadic) {
+          // We allow a zero-parameter variadic function in C if the
+          // function is marked with the "overloadable"
+          // attribute. Scan for this attribute now.
+          bool Overloadable = false;
+          for (const AttributeList *Attrs = D.getAttributes();
+               Attrs; Attrs = Attrs->getNext()) {
+            if (Attrs->getKind() == AttributeList::AT_overloadable) {
+              Overloadable = true;
+              break;
+            }
+          }
+
+          if (!Overloadable)
+            Diag(FTI.getEllipsisLoc(), diag::err_ellipsis_first_arg);
+          T = Context.getFunctionType(T, NULL, 0, FTI.isVariadic, 0);
         } else {
           // Simple void foo(), where the incoming T is the result type.
           T = Context.getFunctionTypeNoProto(T);