Improved semantic analysis and AST respresentation for function
templates.

For example, this now type-checks (but does not instantiate the body
of deref<int>):

  template<typename T> T& deref(T* t) { return *t; }

  void test(int *ip) {
    int &ir = deref(ip);
  }

Specific changes/additions:
  * Template argument deduction from a call to a function template.
  * Instantiation of a function template specializations (just the
  declarations) from the template arguments deduced from a call.
  * FunctionTemplateDecls are stored directly in declaration contexts
  and found via name lookup (all forms), rather than finding the
  FunctionDecl and then realizing it is a template. This is
  responsible for most of the churn, since some of the core
  declaration matching and lookup code assumes that all functions are
  FunctionDecls.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@74213 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/DeclCXX.cpp b/lib/AST/DeclCXX.cpp
index 25e4d19..752218d 100644
--- a/lib/AST/DeclCXX.cpp
+++ b/lib/AST/DeclCXX.cpp
@@ -420,6 +420,15 @@
   return new (C) OverloadedFunctionDecl(DC, N);
 }
 
+void OverloadedFunctionDecl::addOverload(FunctionTemplateDecl *FTD) {
+  Functions.push_back(FTD);
+  
+  // An overloaded function declaration always has the location of
+  // the most-recently-added function declaration.
+  if (FTD->getLocation().isValid())
+    this->setLocation(FTD->getLocation());  
+}
+
 LinkageSpecDecl *LinkageSpecDecl::Create(ASTContext &C,
                                          DeclContext *DC, 
                                          SourceLocation L,