gdbsupport/selftest: Allow lazy registration

This patch adds a way to delay the registration of tests until the
latest possible moment.  This is intended for situations where GDB needs
to be fully initialized in order to decide if a particular selftest can
be executed or not.

This mechanism will be used in the next patch.

Change-Id: I7f6b061f4c0a6832226c7080ab4e3a2523e1b0b0

1 files changed, 21 insertions, 0 deletions

diff --git a/gdbsupport/selftest.cc b/gdbsupport/selftest.cc
index 7077f11..1b862bb 100644
--- a/gdbsupport/selftest.cc
+++ b/gdbsupport/selftest.cc
@@ -30,6 +30,11 @@ namespace selftests
 
 static selftests_registry tests;
 
+/* Set of callback functions used to register selftests after GDB is fully
+   initialized.  */
+
+static std::vector<selftests_generator> lazy_generators;
+
 /* See selftest.h.  */
 
 void
@@ -44,6 +49,14 @@ register_test (const std::string &name,
 
 /* See selftest.h.  */
 
+void
+add_lazy_generator (selftests_generator generator)
+{
+  lazy_generators.push_back (std::move (generator));
+}
+
+/* See selftest.h.  */
+
 static bool run_verbose_ = false;
 
 /* See selftest.h.  */
@@ -104,6 +117,14 @@ run_tests (gdb::array_view<const char *const> filters, bool verbose)
 selftests_range
 all_selftests ()
 {
+  /* Execute any function which might still want to register tests.  Once each
+     function has been executed, clear lazy_generators to ensure that
+     callback functions are only executed once.  */
+  for (const auto &generator : lazy_generators)
+    for (selftest &test : generator ())
+      register_test (std::move (test.name), std::move (test.test));
+  lazy_generators.clear ();
+
   return selftests_range (tests.cbegin (), tests.cend ());
 }