[gcc r14-8127] gccrs: Add a function to check if a function is variadic

[Arthur Cohen]

https://gcc.gnu.org/g:41f480d16d3c6cc1e901d2ae3fcd4a9b5706aa51

commit r14-8127-g41f480d16d3c6cc1e901d2ae3fcd4a9b5706aa51
Author: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>
Date:   Wed Oct 18 15:04:58 2023 +0200

    gccrs: Add a function to check if a function is variadic
    
    This function provides an easy way to check for a function's varidicity.
    
    gcc/rust/ChangeLog:
    
            * ast/rust-item.h: Add a getter to check if a given function is
            variadic.
    
    Signed-off-by: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>

Diff:
---
 gcc/rust/ast/rust-item.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/gcc/rust/ast/rust-item.h b/gcc/rust/ast/rust-item.h
index 38d8b53a43c..109680a1d78 100644
--- a/gcc/rust/ast/rust-item.h
+++ b/gcc/rust/ast/rust-item.h
@@ -1682,6 +1682,12 @@ public:
 
   void accept_vis (ASTVisitor &vis) override;
 
+  bool is_variadic () const
+  {
+    return function_params.size () != 0
+	   && function_params.back ().is_variadic ();
+  }
+
   // Invalid if block is null, so base stripping on that.
   void mark_for_strip () override { function_body = nullptr; }
   bool is_marked_for_strip () const override