compiler: support export/import of unsafe.Add/Slice

For golang/go#19367
For golang/go#40481

Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/340549

1 files changed, 18 insertions, 3 deletions

diff --git a/gcc/go/gofrontend/expressions.h b/gcc/go/gofrontend/expressions.h
index 79a8785..9f8f4e9 100644
--- a/gcc/go/gofrontend/expressions.h
+++ b/gcc/go/gofrontend/expressions.h
@@ -732,6 +732,10 @@ class Expression
   call_expression()
   { return this->convert<Call_expression, EXPRESSION_CALL>(); }
 
+  const Call_expression*
+  call_expression() const
+  { return this->convert<const Call_expression, EXPRESSION_CALL>(); }
+
   // If this is a call_result expression, return the Call_result_expression
   // structure.  Otherwise, return NULL.  This is a controlled dynamic
   // cast.
@@ -2460,13 +2464,16 @@ class Call_expression : public Expression
 
   // Whether this is a call to builtin function.
   virtual bool
-  is_builtin()
+  is_builtin() const
   { return false; }
 
   // Convert to a Builtin_call_expression, or return NULL.
   inline Builtin_call_expression*
   builtin_call_expression();
 
+  inline const Builtin_call_expression*
+  builtin_call_expression() const;
+
  protected:
   int
   do_traverse(Traverse*);
@@ -2625,12 +2632,12 @@ class Builtin_call_expression : public Call_expression
     };
 
   Builtin_function_code
-  code()
+  code() const
   { return this->code_; }
 
   // This overrides Call_expression::is_builtin.
   bool
-  is_builtin()
+  is_builtin() const
   { return true; }
 
   // Return whether EXPR, of array type, is a constant if passed to
@@ -2726,6 +2733,14 @@ Call_expression::builtin_call_expression()
           : NULL);
 }
 
+inline const Builtin_call_expression*
+Call_expression::builtin_call_expression() const
+{
+  return (this->is_builtin()
+          ? static_cast<const Builtin_call_expression*>(this)
+          : NULL);
+}
+
 // A single result from a call which returns multiple results.
 
 class Call_result_expression : public Expression