compiler: `ASuperstringExpr` store the native array in a static variable

Signed-off-by: Jean Privat <jean@pryen.org>

diff --git a/src/compiler/abstract_compiler.nit b/src/compiler/abstract_compiler.nit
index 522230f..dfaa3a3 100644 (file)
--- a/src/compiler/abstract_compiler.nit
+++ b/src/compiler/abstract_compiler.nit
@@ -2786,10 +2786,24 @@ redef class ASuperstringExpr
                        array.add(ne)
                end
 
+               # Store the allocated native array in a static variable
+               # For reusing later
+               var varonce = v.get_name("varonce")
+               v.add("if (unlikely({varonce}==NULL)) \{")
+
                # The native array that will contains the elements to_s-ized.
                # For fast concatenation.
                var a = v.native_array_instance(type_string, v.int_instance(array.length))
 
+               v.add_decl("static {a.mtype.ctype} {varonce};")
+               v.add("\} else \{")
+               # Take the native-array from the store.
+               # The point is to prevent that some recursive execution use (and corrupt) the same native array
+               # WARNING: not thread safe! (FIXME?)
+               v.add("{a} = {varonce};")
+               v.add("{varonce} = NULL;")
+               v.add("\}")
+
                # Stringify the elements and put them in the native array
                var to_s_method = v.get_property("to_s", v.object_type)
                for i in [0..array.length[ do
@@ -2804,6 +2818,10 @@ redef class ASuperstringExpr
 
                # Fast join the native string to get the result
                var res = v.send(v.get_property("native_to_s", a.mtype), [a])
+
+               # We finish to work with the native array,
+               # so store it so that it can be reused
+               v.add("{varonce} = {a};")
                return res
        end
 end