fix codegen support for alloc_size attribute for static C++ methods
add test case for C++ codegen

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@157500 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGCall.cpp b/lib/CodeGen/CGCall.cpp
index 650fe8b..cd01fa2 100644
--- a/lib/CodeGen/CGCall.cpp
+++ b/lib/CodeGen/CGCall.cpp
@@ -2090,9 +2090,11 @@
   // add metadata for __attribute__((alloc_size(foo)))
   if (TargetDecl) {
     if (const AllocSizeAttr* Attr = TargetDecl->getAttr<AllocSizeAttr>()) {
-      std::vector<llvm::Value*> Args;
+      SmallVector<llvm::Value*, 4> Args;
       llvm::IntegerType *Ty = llvm::IntegerType::getInt32Ty(getLLVMContext());
-      bool isMethod = isa<CXXMethodDecl>(TargetDecl);
+      bool isMethod = false;
+      if (const CXXMethodDecl *MDecl = dyn_cast<CXXMethodDecl>(TargetDecl))
+        isMethod = MDecl->isInstance();
 
       for (AllocSizeAttr::args_iterator I = Attr->args_begin(),
            E = Attr->args_end(); I != E; ++I) {