Several improvements from Doug Gregor related to default
argument handling.  I'll fix up the c89 (void) thing next.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@49459 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/Decl.cpp b/lib/AST/Decl.cpp
index afe4fcd..2ef31e4 100644
--- a/lib/AST/Decl.cpp
+++ b/lib/AST/Decl.cpp
@@ -385,6 +385,19 @@
   }
 }
 
+/// getMinRequiredArguments - Returns the minimum number of arguments
+/// needed to call this function. This may be fewer than the number of
+/// function parameters, if some of the parameters have default
+/// arguments.
+unsigned FunctionDecl::getMinRequiredArguments() const {
+  unsigned NumRequiredArgs = getNumParams();
+  while (NumRequiredArgs > 0
+         && getParamDecl(NumRequiredArgs-1)->getDefaultArg())
+    --NumRequiredArgs;
+
+  return NumRequiredArgs;
+}
+
 //===----------------------------------------------------------------------===//
 // RecordDecl Implementation
 //===----------------------------------------------------------------------===//