Add ggc-tests.c

gcc/ChangeLog:
	* Makefile.in (OBJS): Add ggc-tests.o.
	(GTFILES): Add ggc-tests.c.
	* ggc-tests.c: New file.
	* selftest-run-tests.c (selftest::run_tests): Call
	selftest::ggc_tests_c_tests.
	* selftest.h (selftest::ggc_tests_c_tests): New prototype.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@237309 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 523 insertions, 0 deletions

diff --git a/gcc/ggc-tests.c b/gcc/ggc-tests.c
new file mode 100644
index 00000000000..48eac03103b
--- /dev/null
+++ b/gcc/ggc-tests.c
@@ -0,0 +1,523 @@
+/* Unit tests for GCC's garbage collector (and gengtype etc).
+   Copyright (C) 2015-2016 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tree-core.h"
+#include "tree.h"
+#include "ggc-internal.h" /* (for ggc_force_collect).  */
+#include "selftest.h"
+
+#if CHECKING_P
+
+/* The various GTY markers must be outside of a namespace to be seen by
+   gengtype, so we don't put this file within the selftest namespace.  */
+
+/* A helper function for writing ggc tests.  */
+
+static void
+forcibly_ggc_collect ()
+{
+  ggc_force_collect = true;
+  ggc_collect ();
+  ggc_force_collect = false;
+}
+
+
+
+/* Verify that a simple struct works, and that it can
+   own references to non-roots, and have them be marked.  */
+
+struct GTY(()) test_struct
+{
+  struct test_struct *other;
+};
+
+static GTY(()) test_struct *root_test_struct;
+
+static void
+test_basic_struct ()
+{
+  root_test_struct = ggc_cleared_alloc <test_struct> ();
+  root_test_struct->other = ggc_cleared_alloc <test_struct> ();
+
+  forcibly_ggc_collect ();
+
+  ASSERT_TRUE (ggc_marked_p (root_test_struct));
+  ASSERT_TRUE (ggc_marked_p (root_test_struct->other));
+}
+
+
+
+/* Selftest for GTY((length)).  */
+
+/* A test struct using GTY((length)).  */
+
+struct GTY(()) test_of_length
+{
+  int num_elem;
+  struct test_of_length * GTY ((length ("%h.num_elem"))) elem[1];
+};
+
+static GTY(()) test_of_length *root_test_of_length;
+
+static void
+test_length ()
+{
+  const int count = 5;
+  size_t sz = sizeof (test_of_length) + (count- 1) * sizeof (test_of_length *);
+  root_test_of_length = (test_of_length *)ggc_internal_cleared_alloc (sz);
+  root_test_of_length->num_elem = count;
+  for (int i = 0; i < count; i++)
+    root_test_of_length->elem[i] = ggc_cleared_alloc <test_of_length> ();
+
+  forcibly_ggc_collect ();
+
+  ASSERT_TRUE (ggc_marked_p (root_test_of_length));
+  for (int i = 0; i < count; i++)
+    ASSERT_TRUE (ggc_marked_p (root_test_of_length->elem[i]));
+}
+
+
+
+/* Selftest for unions, GTY((tag)), and GTY((desc)).  */
+
+/* A struct with a reference that's an a different offset to test_struct,
+   to ensure that we're using the correct types.  */
+
+struct GTY(()) test_other
+{
+  char dummy[256];
+  test_struct *m_ptr;
+};
+
+enum which_field
+{
+  WHICH_FIELD_USE_TEST_STRUCT,
+  WHICH_FIELD_USE_TEST_OTHER
+};
+
+/* An example function for use by a GTY((desc)) marker.  */
+
+static enum which_field
+calc_desc (int kind)
+{
+  switch (kind)
+    {
+    case 0: return WHICH_FIELD_USE_TEST_STRUCT;
+    case 1: return WHICH_FIELD_USE_TEST_OTHER;
+    default:
+      gcc_unreachable ();
+    }
+}
+
+/* A struct containing an example of a union, showing the "tag" and
+   "desc" markers.  */
+
+struct GTY(()) test_of_union
+{
+  int m_kind;
+  union u {
+    test_struct * GTY ((tag ("WHICH_FIELD_USE_TEST_STRUCT") )) u_test_struct;
+    test_other * GTY ((tag ("WHICH_FIELD_USE_TEST_OTHER") )) u_test_other;
+  } GTY ((desc ("calc_desc (%0.m_kind)"))) m_u;
+};
+
+/* Example roots.  */
+
+static GTY(()) test_of_union *root_test_of_union_1;
+static GTY(()) test_of_union *root_test_of_union_2;
+
+/* Verify that the above work correctly.  */
+
+static void
+test_union ()
+{
+  root_test_of_union_1 = ggc_cleared_alloc <test_of_union> ();
+  root_test_of_union_1->m_kind = 0;
+  test_struct *ts = ggc_cleared_alloc <test_struct> ();
+  root_test_of_union_1->m_u.u_test_struct = ts;
+
+  root_test_of_union_2 = ggc_cleared_alloc <test_of_union> ();
+  root_test_of_union_2->m_kind = 1;
+  test_other *other = ggc_cleared_alloc <test_other> ();
+  root_test_of_union_2->m_u.u_test_other = other;
+  test_struct *referenced_by_other = ggc_cleared_alloc <test_struct> ();
+  other->m_ptr = referenced_by_other;
+
+  forcibly_ggc_collect ();
+
+  ASSERT_TRUE (ggc_marked_p (root_test_of_union_1));
+  ASSERT_TRUE (ggc_marked_p (ts));
+
+  ASSERT_TRUE (ggc_marked_p (root_test_of_union_2));
+  ASSERT_TRUE (ggc_marked_p (other));
+  ASSERT_TRUE (ggc_marked_p (referenced_by_other));
+}
+
+
+
+/* Verify that destructors get run when instances are collected.  */
+
+struct GTY(()) test_struct_with_dtor
+{
+  /* This struct has a destructor; it *ought* to be called
+     by the ggc machinery when instances are collected.  */
+  ~test_struct_with_dtor () { dtor_call_count++; }
+
+  static int dtor_call_count;
+};
+
+int test_struct_with_dtor::dtor_call_count;
+
+static void
+test_finalization ()
+{
+  ASSERT_FALSE (need_finalization_p <test_struct> ());
+  ASSERT_TRUE (need_finalization_p <test_struct_with_dtor> ());
+
+  /* Create some garbage.  */
+  const int count = 10;
+  for (int i = 0; i < count; i++)
+    ggc_cleared_alloc <test_struct_with_dtor> ();
+
+  test_struct_with_dtor::dtor_call_count = 0;
+
+  forcibly_ggc_collect ();
+
+  /* Verify that the destructor was run for each instance.  */
+  ASSERT_EQ (count, test_struct_with_dtor::dtor_call_count);
+}
+
+
+
+/* Verify that a global can be marked as "deletable".  */
+
+static GTY((deletable)) test_struct *test_of_deletable;
+
+static void
+test_deletable_global ()
+{
+  test_of_deletable = ggc_cleared_alloc <test_struct> ();
+  ASSERT_TRUE (test_of_deletable != NULL);
+
+  forcibly_ggc_collect ();
+
+  ASSERT_EQ (NULL, test_of_deletable);
+}
+
+
+
+/* Verify that gengtype etc can cope with inheritance.  */
+
+class GTY((desc("%h.m_kind"), tag("0"))) example_base
+{
+ public:
+  example_base ()
+    : m_kind (0),
+      m_a (ggc_cleared_alloc <test_struct> ())
+  {}
+
+  void *
+  operator new (size_t sz)
+  {
+    return ggc_internal_cleared_alloc (sz);
+  }
+
+ protected:
+  example_base (int kind)
+    : m_kind (kind),
+      m_a (ggc_cleared_alloc <test_struct> ())
+  {}
+
+ public:
+  int m_kind;
+  test_struct *m_a;
+};
+
+class GTY((tag("1"))) some_subclass : public example_base
+{
+ public:
+  some_subclass ()
+    : example_base (1),
+      m_b (ggc_cleared_alloc <test_struct> ())
+  {}
+
+  test_struct *m_b;
+};
+
+class GTY((tag("2"))) some_other_subclass : public example_base
+{
+ public:
+  some_other_subclass ()
+    : example_base (2),
+      m_c (ggc_cleared_alloc <test_struct> ())
+  {}
+
+  test_struct *m_c;
+};
+
+/* Various test roots, both expressed as a ptr to the actual class, and
+   as a ptr to the base class.  */
+static GTY(()) example_base *test_example_base;
+static GTY(()) some_subclass *test_some_subclass;
+static GTY(()) some_other_subclass *test_some_other_subclass;
+static GTY(()) example_base *test_some_subclass_as_base_ptr;
+static GTY(()) example_base *test_some_other_subclass_as_base_ptr;
+
+static void
+test_inheritance ()
+{
+  test_example_base = new example_base ();
+  test_some_subclass = new some_subclass ();
+  test_some_other_subclass = new some_other_subclass ();
+  test_some_subclass_as_base_ptr = new some_subclass ();
+  test_some_other_subclass_as_base_ptr = new some_other_subclass ();
+
+  forcibly_ggc_collect ();
+
+  /* Verify that the roots and everything referenced by them got marked
+     (both for fields in the base class and those in subclasses).  */
+  ASSERT_TRUE (ggc_marked_p (test_example_base));
+  ASSERT_TRUE (ggc_marked_p (test_example_base->m_a));
+
+  ASSERT_TRUE (ggc_marked_p (test_some_subclass));
+  ASSERT_TRUE (ggc_marked_p (test_some_subclass->m_a));
+  ASSERT_TRUE (ggc_marked_p (test_some_subclass->m_b));
+
+  ASSERT_TRUE (ggc_marked_p (test_some_other_subclass));
+  ASSERT_TRUE (ggc_marked_p (test_some_other_subclass->m_a));
+  ASSERT_TRUE (ggc_marked_p (test_some_other_subclass->m_c));
+
+  ASSERT_TRUE (ggc_marked_p (test_some_subclass_as_base_ptr));
+  ASSERT_TRUE (ggc_marked_p (test_some_subclass_as_base_ptr->m_a));
+  ASSERT_TRUE (ggc_marked_p (((some_subclass *)
+			      test_some_subclass_as_base_ptr)->m_b));
+
+  ASSERT_TRUE (ggc_marked_p (test_some_other_subclass_as_base_ptr));
+  ASSERT_TRUE (ggc_marked_p (test_some_other_subclass_as_base_ptr->m_a));
+  ASSERT_TRUE (ggc_marked_p (((some_other_subclass *)
+			      test_some_other_subclass_as_base_ptr)->m_c));
+}
+
+
+
+/* Test of chain_next/chain_prev
+
+   Construct a very long linked list, so that without
+   the chain_next/chain_prev optimization we'd have
+   a stack overflow when gt_ggc_mx_test_node recurses.  */
+
+struct GTY(( chain_next ("%h.m_next"),
+	     chain_prev ("%h.m_prev") )) test_node
+{
+  test_node *m_prev;
+  test_node *m_next;
+  int m_idx;
+};
+
+static GTY(()) test_node *root_test_node;
+
+static void
+test_chain_next ()
+{
+  /* Ideally we would construct a long list so that the number of
+     stack frames would be deep enough to crash if gengtype has created
+     something that recurses.
+
+     However, as the list is lengthened to increase the chance of
+     overflowing the stack, the test will require more time and memory
+     to run.  On a Fedora 20 x86_64 box with 128GB of RAM, count=2000000
+     without the chain_next optimization reliably overflowed the stack,
+     but the test took 0.5s to run.
+
+     For now this test runs with a low value for "count", which defeats
+     the main purpose of the test - though it at least gives us coverage
+     for walking a GTY((chain_next)) list.
+
+     We could potentially increase this value once we have a better sense
+     of the time and space requirements of the test on different hosts,
+     or perhaps find a way to reduce the stack size when running this
+     testcase.  */
+  const int count = 10;
+
+  /* Build the linked list.  */
+  root_test_node = ggc_cleared_alloc <test_node> ();
+  test_node *tail_node = root_test_node;
+  for (int i = 0; i < count; i++)
+    {
+      test_node *new_node = ggc_cleared_alloc <test_node> ();
+      tail_node->m_next = new_node;
+      new_node->m_prev = tail_node;
+      new_node->m_idx = i;
+      tail_node = new_node;
+    }
+
+  forcibly_ggc_collect ();
+
+  /* If we got here, we survived.  */
+
+  /* Verify that all nodes in the list were marked.  */
+  ASSERT_TRUE (ggc_marked_p (root_test_node));
+  test_node *iter_node = root_test_node->m_next;
+  for (int i = 0; i < count; i++)
+    {
+      ASSERT_TRUE (ggc_marked_p (iter_node));
+      ASSERT_EQ (i, iter_node->m_idx);
+      iter_node = iter_node->m_next;
+    }
+}
+
+
+
+/* Test for GTY((user)).  */
+
+struct GTY((user)) user_struct
+{
+  char dummy[16];
+  test_struct *m_ptr;
+};
+
+static GTY(()) user_struct *root_user_struct_ptr;
+
+/* A global for verifying that the user-provided gt_ggc_mx gets
+   called.  */
+static int num_calls_to_user_gt_ggc_mx;
+
+/* User-provided implementation of gt_ggc_mx.  */
+
+static void
+gt_ggc_mx (user_struct *p)
+{
+  num_calls_to_user_gt_ggc_mx++;
+  gt_ggc_mx_test_struct (p->m_ptr);
+}
+
+/* User-provided implementation of gt_pch_nx.  */
+
+static void
+gt_pch_nx (user_struct *p)
+{
+  gt_pch_nx_test_struct (p->m_ptr);
+}
+
+/* User-provided implementation of gt_pch_nx.  */
+
+static void
+gt_pch_nx (user_struct *p, gt_pointer_operator op, void *cookie)
+{
+  op (&(p->m_ptr), cookie);
+}
+
+/* Verify that GTY((user)) works.  */
+
+static void
+test_user_struct ()
+{
+  root_user_struct_ptr = ggc_cleared_alloc <user_struct> ();
+  test_struct *referenced = ggc_cleared_alloc <test_struct> ();
+  root_user_struct_ptr->m_ptr = referenced;
+
+  num_calls_to_user_gt_ggc_mx = 0;
+
+  forcibly_ggc_collect ();
+
+  ASSERT_TRUE (ggc_marked_p (root_user_struct_ptr));
+  ASSERT_TRUE (ggc_marked_p (referenced));
+  ASSERT_TRUE (num_calls_to_user_gt_ggc_mx > 0);
+}
+
+
+
+/* Smoketest to ensure that the tree type is marked.  */
+
+static GTY(()) tree dummy_unittesting_tree;
+
+static void
+test_tree_marking ()
+{
+  dummy_unittesting_tree = build_int_cst (integer_type_node, 1066);
+
+  forcibly_ggc_collect ();
+
+  ASSERT_TRUE (ggc_marked_p (dummy_unittesting_tree));
+}
+
+
+
+/* Ideas for other tests:
+   - pch-handling  */
+
+namespace selftest {
+
+/* Run all of the selftests within this file.  */
+
+void
+ggc_tests_c_tests ()
+{
+  test_basic_struct ();
+  test_length ();
+  test_union ();
+  test_finalization ();
+  test_deletable_global ();
+  test_inheritance ();
+  test_chain_next ();
+  test_user_struct ();
+  test_tree_marking ();
+}
+
+} // namespace selftest
+
+#include "gt-ggc-tests.h"
+
+#else /* #if CHECKING_P */
+
+/* The #if CHECKING_P code above has various GTY-marked roots.
+   gengtype has no knowledge of the preprocessor, and so detects
+   these roots and writes them out to gt-ggc-tests.h.
+   In a !CHECKING_P build we can ignore gt-ggc-tests.h, but the
+   root tables are referenced in the various generated gtype-*.c
+   files like this:
+
+      ...snip...
+      extern const struct ggc_root_tab gt_ggc_r_gt_ggc_tests_h[];
+      ...snip...
+
+      EXPORTED_CONST struct ggc_root_tab * const gt_ggc_rtab[] = {
+        ...snip...
+        gt_ggc_r_gt_ggc_tests_h,
+        ...snip...
+      };
+
+    Hence to avoid a link failure, we provide dummy implementations
+    of these root tables in an unchecked build.
+
+    Note that these conditional roots imply that PCH files are
+    incompatible between checked and unchecked builds.  */
+
+EXPORTED_CONST struct ggc_root_tab gt_ggc_r_gt_ggc_tests_h[] = {
+  LAST_GGC_ROOT_TAB
+};
+
+EXPORTED_CONST struct ggc_root_tab gt_ggc_rd_gt_ggc_tests_h[] = {
+  LAST_GGC_ROOT_TAB
+};
+
+#endif /* #else clause of #if CHECKING_P */