PNaCl Dynamic Linking: Added portable dependencies to shared objects.

tests/pnacl_dynamic_loading/dependencies_test.c

+/*
+ * Copyright 2016 The Native Client Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include <stdio.h>
+
+/*
+ * These functions would typically be declared in a shared header file, but for
+ * testing convenience, they are defined here.
+ */
+int get_module_a_var();
+int get_module_b_var();
+int get_module_c_var();
+
+/*
+ * The loader should only need to load "dependencies_test", and the dependencies
+ * should by loaded automatically by the pll_loader.
+ *
+ * | dependencies_test (depends on libc and test_pll_c)
+ *   | libc
+ *     * No dependencies
+ *   | test_pll_c (depends on test_pll_a and test_pll_b)
+ *     | test_pll_a
+ *       * No dependencies
+ *     | test_pll_b (depends on test_pll_a)
+ *       | test_pll_a
+ *         * No dependencies
+ */
+
+int main(int argc, char* argv[]) {
+  printf("%d\n", get_module_a_var());

[Mark Seaborn, 2016/03/30 23:24:57]

I would be inclined to use
ASSERT_EQ(get_module_a_var(), 2345);

Then you don't need the golden file.

But that does assume that you can be sure that main() gets called. :-)  If
you're worried about that, you could do both:  use ASSERT_EQ, but also do
printf("main() called\n") and have the golden file check that.

[Mark Seaborn, 2016/04/01 19:10:42]

As you discovered, that currently doesn't work, because it refers to stderr,
which (oddly) generates a reference to a TLS variable in newlib.

So let's leave these as printf() calls until we have cross-module TLS references
implemented.

[Sean Klein, 2016/04/01 23:12:25]

Done.

+  printf("%d\n", get_module_b_var());
+  printf("%d\n", get_module_c_var());
+  return 0;
+}