libdl: Add object file dependencies to track references

Tracking references lets us manage when an object file can be
unloaded. If an object file has references to it, it cannot be
unloaded.

Modules that depend on each other cannot be unloaded.

Updates #3605

1 files changed, 56 insertions, 0 deletions

diff --git a/testsuites/libtests/dl07/dl-o1.c b/testsuites/libtests/dl07/dl-o1.c
new file mode 100644
index 0000000000..af5ad1bd17
--- /dev/null
+++ b/testsuites/libtests/dl07/dl-o1.c
@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2018 Chris Johns <chrisj@rtems.org>.
+ * All rights reserved.
+ *
+ * The license and distribution terms for this file may be
+ * found in the file LICENSE in this distribution or at
+ * http://www.rtems.org/license/LICENSE.
+ */
+
+#include "dl-o1.h"
+
+#include <rtems/test.h>
+#include "dl-load.h"
+
+#define printf(...) rtems_printf(&rtems_test_printer, __VA_ARGS__);
+
+/*
+ * Create some symbols. The uninitialised will be in the common section with
+ * separated text and data and this means there is no actual section in the ELF
+ * file, the details for this are in the symbols.
+ */
+int         dl01_bss1;            /* unitialised, .bss */
+float       dl01_bss2[30];        /* unitialised, .bss */
+char        dl01_bss3[10];        /* unitialised, .bss */
+int         dl01_data1 = 1;       /* initialised, .data */
+float       dl01_data2 = 0.3333;  /* initialised, .data */
+const int   dl01_const1 = 3;      /* read-only, .const */
+const float dl01_const2 = 0.666;  /* read-only, .const */
+int dl01_func1(void)              /* code, .text */
+{
+  return 4;
+}
+
+/*
+ * Yes a decl in the source. This is a modules main and I could not find which
+ * header main is defined in.
+ */
+int rtems_main_o1 (void);
+
+#define DL_NAME       "dlo1"
+#define PAINT_VAR(_v) sizeof(_v), &_v, _v
+
+int rtems_main_o1 (void)
+{
+  printf (DL_NAME ": module: %s\n", dl_localise_file (__FILE__));
+  printf (DL_NAME ":         dl01_bss1: %4u: %p: %d\n",   PAINT_VAR (dl01_bss1));
+  printf (DL_NAME ":         dl01_bss2: %4u: %p: %f\n",   PAINT_VAR (dl01_bss2[0]));
+  printf (DL_NAME ":         dl01_bss3: %4u: %p: %02x\n", PAINT_VAR (dl01_bss3[0]));
+  printf (DL_NAME ":        dl01_data1: %4u: %p: %d\n",   PAINT_VAR (dl01_data1));
+  /* no  %f in the rtems test printer */
+  printf (DL_NAME ":        dl01_data2: %4u: %p: %f\n",   PAINT_VAR (dl01_data2));
+  printf (DL_NAME ":       dl01_const1: %4u: %p: %d\n",   PAINT_VAR (dl01_const1));
+  printf (DL_NAME ":       dl01_const2: %4u: %p: %f\n",   PAINT_VAR (dl01_const2));
+  printf (DL_NAME ":        dl01_func1: %4u: %p\n",       sizeof(dl01_func1), &dl01_func1);
+  return 0;
+}