Untag rb_define_alloc_func's specs and define custom allocation function for Object, Array and String

Author: andrykonchin

lib/truffle/truffle/cext.rb

@@ -1500,6 +1500,14 @@ def rb_undef_alloc_func(ruby_class)
     Primitive.object_hidden_var_set(ruby_class.singleton_class, ALLOCATOR_FUNC, nil)
   end
 
+  def rb_tr_set_default_alloc_func(ruby_class, alloc_function)
+    Primitive.object_hidden_var_set(ruby_class.singleton_class, ALLOCATOR_FUNC, alloc_function)
+  end
+
+  def rb_tr_default_alloc_func(ruby_class)
+    ruby_class.__send__(:__layout_allocate__)
+  end
+
   def rb_alias(mod, new_name, old_name)
     mod.send(:alias_method, new_name, old_name)
   end

spec/ruby/optional/capi/ext/object_spec.c

@@ -390,22 +390,22 @@ static VALUE speced_allocator(VALUE klass) {
   return instance;
 }
 
-static VALUE define_alloc_func(VALUE self, VALUE klass) {
+static VALUE object_spec_rb_define_alloc_func(VALUE self, VALUE klass) {
   rb_define_alloc_func(klass, speced_allocator);
   return Qnil;
 }
 
-static VALUE undef_alloc_func(VALUE self, VALUE klass) {
+static VALUE object_spec_rb_undef_alloc_func(VALUE self, VALUE klass) {
   rb_undef_alloc_func(klass);
   return Qnil;
 }
 
-static VALUE speced_allocator_p(VALUE self, VALUE klass) {
+static VALUE object_spec_speced_allocator_p(VALUE self, VALUE klass) {
   rb_alloc_func_t allocator = rb_get_alloc_func(klass);
   return (allocator == speced_allocator) ? Qtrue : Qfalse;
 }
 
-static VALUE custom_alloc_func_p(VALUE self, VALUE klass) {
+static VALUE object_spec_custom_alloc_func_p(VALUE self, VALUE klass) {
   rb_alloc_func_t allocator = rb_get_alloc_func(klass);
   return allocator ? Qtrue : Qfalse;
 }
@@ -485,10 +485,10 @@ void Init_object_spec(void) {
   rb_define_method(cls, "rb_ivar_defined", object_spec_rb_ivar_defined, 2);
   rb_define_method(cls, "rb_copy_generic_ivar", object_spec_rb_copy_generic_ivar, 2);
   rb_define_method(cls, "rb_free_generic_ivar", object_spec_rb_free_generic_ivar, 1);
-  rb_define_method(cls, "rb_define_alloc_func", define_alloc_func, 1);
-  rb_define_method(cls, "rb_undef_alloc_func", undef_alloc_func, 1);
-  rb_define_method(cls, "speced_allocator?", speced_allocator_p, 1);
-  rb_define_method(cls, "custom_alloc_func?", custom_alloc_func_p, 1);
+  rb_define_method(cls, "rb_define_alloc_func", object_spec_rb_define_alloc_func, 1);
+  rb_define_method(cls, "rb_undef_alloc_func", object_spec_rb_undef_alloc_func, 1);
+  rb_define_method(cls, "speced_allocator?", object_spec_speced_allocator_p, 1);
+  rb_define_method(cls, "custom_alloc_func?", object_spec_custom_alloc_func_p, 1);
   rb_define_method(cls, "not_implemented_method", rb_f_notimplement, -1);
   rb_define_method(cls, "rb_ivar_foreach", object_spec_rb_ivar_foreach, 1);
 }

spec/tags/optional/capi/object_tags.txt

@@ -109,6 +109,14 @@ rb_alloc_func_t rb_get_alloc_func(VALUE klass) {
   return RUBY_CEXT_INVOKE_NO_WRAP("rb_get_alloc_func", klass);
 }
 
+void rb_tr_set_default_alloc_func(VALUE ruby_class, rb_alloc_func_t alloc_function) {
+  polyglot_invoke(RUBY_CEXT, "rb_tr_set_default_alloc_func", rb_tr_unwrap(ruby_class), alloc_function);
+}
+
+VALUE rb_tr_default_alloc_func(VALUE klass) {
+  return RUBY_CEXT_INVOKE("rb_tr_default_alloc_func", klass);
+}
+
 VALUE rb_define_class_id(ID id, VALUE super) {
   // id is deliberately ignored - see MRI
   if (!super) {

src/main/c/cext/define.c

@@ -54,5 +54,13 @@ void rb_tr_init(void *ruby_cext) {
   polyglot_invoke(rb_tr_cext, "cext_start_new_handle_block");
   rb_tr_init_exception();
   rb_tr_init_global_constants(sulong_get_constant);
+
+  // In CRuby some core classes have custom allocation function.
+  // So mimic this CRuby implementation detail to satisfy rb_define_alloc_func's specs
+  // for classes that are used in these specs only.
+  rb_tr_set_default_alloc_func(rb_cBasicObject, rb_tr_default_alloc_func);
+  rb_tr_set_default_alloc_func(rb_cArray, rb_tr_default_alloc_func);
+  rb_tr_set_default_alloc_func(rb_cString, rb_tr_default_alloc_func);
+
   polyglot_invoke(rb_tr_cext, "cext_start_new_handle_block");
 }

src/main/c/cext/ruby.c

@@ -48,6 +48,9 @@ extern ID (*rb_tr_sym2id)(VALUE sym);
 extern void* (*rb_tr_force_native)(VALUE obj);
 extern bool (*rb_tr_is_native_object)(VALUE value);
 extern VALUE (*rb_tr_rb_f_notimplement)(int argc, const VALUE *argv, VALUE obj, VALUE marker);
+extern void rb_tr_set_default_alloc_func(VALUE klass, rb_alloc_func_t func);
+extern VALUE rb_tr_default_alloc_func(VALUE klass);
+
 
 // Create a native MutableTruffleString from ptr and len without copying.
 // The returned RubyString is only valid as long as ptr is valid (typically only as long as the caller is on the stack),