add ffi_get_struct_offsets

testsuite/libffi.call/offsets.c

@@ -0,0 +1,46 @@
+/* Area:		Struct layout
+   Purpose:		Test ffi_get_struct_offsets
+   Limitations:		none.
+   PR:			none.
+   Originator: 		Tom Tromey. */
+
+/* { dg-do run } */
+#include "ffitest.h"
+#include <stddef.h>
+
+struct test_1
+{
+  char c;
+  float f;
+  char c2;
+  int i;
+};
+
+int
+main (void)
+{
+  ffi_type test_1_type;
+  ffi_type *test_1_elements[5];
+  size_t test_1_offsets[4];
+
+  test_1_elements[0] = &ffi_type_schar;
+  test_1_elements[1] = &ffi_type_float;
+  test_1_elements[2] = &ffi_type_schar;
+  test_1_elements[3] = &ffi_type_sint;
+  test_1_elements[4] = NULL;
+
+  test_1_type.size = 0;
+  test_1_type.alignment = 0;
+  test_1_type.type = FFI_TYPE_STRUCT;
+  test_1_type.elements = test_1_elements;
+
+  CHECK (ffi_get_struct_offsets (FFI_DEFAULT_ABI, &test_1_type, test_1_offsets)
+	 == FFI_OK);
+  CHECK (test_1_type.size == sizeof (struct test_1));
+  CHECK (offsetof (struct test_1, c) == test_1_offsets[0]);
+  CHECK (offsetof (struct test_1, f) == test_1_offsets[1]);
+  CHECK (offsetof (struct test_1, c2) == test_1_offsets[2]);
+  CHECK (offsetof (struct test_1, i) == test_1_offsets[3]);
+
+  return 0;
+}