I left making inferior::detaching a bool to a separate patch, because
doing that makes a make_cleanup_restore_integer call in
infrun.c:prepare_for_detach no longer compile (passing a 'bool *' when
an 'int *' is expected). Since we want to get rid of cleanups anyway,
I looked at converting that to a scoped_restore. However,
prepare_for_detach wants to discard the cleanup on success, and
scoped_restore doesn't have an equivalent for that. So I added one --
I called it "release()" because it seems like a natural fit in the way
standard components call similarly-spirited methods, and, it's also
what the proposal for a generic scope guard calls it too, AFAICS:
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4189.pdf
I've added some scoped_guard unit tests, while at it.
gdb/ChangeLog:
2017-04-19 Pedro Alves <palves@redhat.com>
* Makefile.in (SUBDIR_UNITTESTS_SRCS): Add
unittests/scoped_restore-selftests.c.
(SUBDIR_UNITTESTS_OBS): Add scoped_restore-selftests.o.
* common/scoped_restore.h (scoped_restore_base): Make "class".
(scoped_restore_base::release): New public method.
(scoped_restore_base::scoped_restore_base): New protected ctor.
(scoped_restore_base::m_saved_var): New protected field.
(scoped_restore_tmpl::scoped_restore_tmpl(T*)): Initialize the
scoped_restore_base base class instead of m_saved_var directly.
(scoped_restore_tmpl::scoped_restore_tmpl(T*, T2)): Likewise.
(scoped_restore_tmpl::scoped_restore_tmpl(const
scoped_restore_tmpl<T>&)): Likewise.
(scoped_restore_tmpl::~scoped_restore_tmpl): Use the saved_var
method.
(scoped_restore_tmpl::saved_var): New method.
(scoped_restore_tmpl::m_saved_var): Delete.
* inferior.h (inferior::detaching): Now a bool.
* infrun.c (prepare_for_detach): Use a scoped_restore instead of a
cleanup.
* unittests/scoped_restore-selftests.c: New file.
+2017-04-19 Pedro Alves <palves@redhat.com>
+
+ * Makefile.in (SUBDIR_UNITTESTS_SRCS): Add
+ unittests/scoped_restore-selftests.c.
+ (SUBDIR_UNITTESTS_OBS): Add scoped_restore-selftests.o.
+ * common/scoped_restore.h (scoped_restore_base): Make "class".
+ (scoped_restore_base::release): New public method.
+ (scoped_restore_base::scoped_restore_base): New protected ctor.
+ (scoped_restore_base::m_saved_var): New protected field.
+ (scoped_restore_tmpl::scoped_restore_tmpl(T*)): Initialize the
+ scoped_restore_base base class instead of m_saved_var directly.
+ (scoped_restore_tmpl::scoped_restore_tmpl(T*, T2)): Likewise.
+ (scoped_restore_tmpl::scoped_restore_tmpl(const
+ scoped_restore_tmpl<T>&)): Likewise.
+ (scoped_restore_tmpl::~scoped_restore_tmpl): Use the saved_var
+ method.
+ (scoped_restore_tmpl::saved_var): New method.
+ (scoped_restore_tmpl::m_saved_var): Delete.
+ * inferior.h (inferior::detaching): Now a bool.
+ * infrun.c (prepare_for_detach): Use a scoped_restore instead of a
+ cleanup.
+ * unittests/scoped_restore-selftests.c: New file.
+
2017-04-19 Pedro Alves <palves@redhat.com>
* Makefile.in (SUBDIR_UNITTESTS_SRCS, SUBDIR_UNITTESTS_OBS):
unittests/function-view-selftests.c \
unittests/offset-type-selftests.c \
unittests/optional-selftests.c \
- unittests/ptid-selftests.c
+ unittests/ptid-selftests.c \
+ unittests/scoped_restore-selftests.c
SUBDIR_UNITTESTS_OBS = \
function-view-selftests.o \
offset-type-selftests.o \
optional-selftests.o \
- ptid-selftests.o
+ ptid-selftests.o \
+ scoped_restore-selftests.o
# Opcodes currently live in one of two places. Either they are in the
# opcode library, typically ../opcodes, or they are in a header file
#define SCOPED_RESTORE_H
/* Base class for scoped_restore_tmpl. */
-struct scoped_restore_base
+class scoped_restore_base
{
+public:
+ /* This informs the (scoped_restore_tmpl<T>) dtor that you no longer
+ want the original value restored. */
+ void release () const
+ { m_saved_var = NULL; }
+
+protected:
+ scoped_restore_base (void *saved_var)
+ : m_saved_var (saved_var)
+ {}
+
+ /* The type-erased saved variable. This is here so that clients can
+ call release() on a "scoped_restore" local, which is a typedef to
+ a scoped_restore_base. See below. */
+ mutable void *m_saved_var;
};
/* A convenience typedef. Users of make_scoped_restore declare the
of *VAR. *VAR will be restored when this scoped_restore object
is destroyed. */
scoped_restore_tmpl (T *var)
- : m_saved_var (var),
+ : scoped_restore_base (var),
m_saved_value (*var)
{
}
E.g.: T='base'; T2='derived'. */
template <typename T2>
scoped_restore_tmpl (T *var, T2 value)
- : m_saved_var (var),
+ : scoped_restore_base (var),
m_saved_value (*var)
{
*var = value;
}
scoped_restore_tmpl (const scoped_restore_tmpl<T> &other)
- : m_saved_var (other.m_saved_var),
+ : scoped_restore_base {other.m_saved_var},
m_saved_value (other.m_saved_value)
{
other.m_saved_var = NULL;
~scoped_restore_tmpl ()
{
- if (m_saved_var != NULL)
- *m_saved_var = m_saved_value;
+ if (saved_var () != NULL)
+ *saved_var () = m_saved_value;
}
- private:
+private:
+ /* Return a pointer to the saved variable with its type
+ restored. */
+ T *saved_var ()
+ { return static_cast<T *> (m_saved_var); }
/* No need for this. It is intentionally not defined anywhere. */
scoped_restore_tmpl &operator= (const scoped_restore_tmpl &);
- /* The saved variable. */
- mutable T *m_saved_var;
-
/* The saved value. */
const T m_saved_value;
};
bool waiting_for_vfork_done = false;
/* True if we're in the process of detaching from this inferior. */
- int detaching = 0;
+ bool detaching = false;
/* What is left to do for an execution command after any thread of
this inferior stops. For continuations associated with a
{
struct inferior *inf = current_inferior ();
ptid_t pid_ptid = pid_to_ptid (inf->pid);
- struct cleanup *old_chain_1;
struct displaced_step_inferior_state *displaced;
displaced = get_displaced_stepping_state (inf->pid);
fprintf_unfiltered (gdb_stdlog,
"displaced-stepping in-process while detaching");
- old_chain_1 = make_cleanup_restore_integer (&inf->detaching);
- inf->detaching = 1;
+ scoped_restore restore_detaching = make_scoped_restore (&inf->detaching, true);
while (!ptid_equal (displaced->step_ptid, null_ptid))
{
inferior, so this must mean the process is gone. */
if (!ecs->wait_some_more)
{
- discard_cleanups (old_chain_1);
+ restore_detaching.release ();
error (_("Program exited while detaching"));
}
}
- discard_cleanups (old_chain_1);
+ restore_detaching.release ();
}
/* Wait for control to return from inferior to debugger.
--- /dev/null
+/* Self tests for scoped_restore for GDB, the GNU debugger.
+
+ Copyright (C) 2017 Free Software Foundation, Inc.
+
+ This file is part of GDB.
+
+ This program 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 of the License, or
+ (at your option) any later version.
+
+ This program 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 this program. If not, see <http://www.gnu.org/licenses/>. */
+
+#include "defs.h"
+#include "selftest.h"
+#include "common/scoped_restore.h"
+
+namespace selftests {
+namespace scoped_restore_tests {
+
+struct Base {};
+struct Derived : Base {};
+
+static int global;
+
+/* Check that we can return a scoped_restore from a function. Below
+ we'll make sure this does the right thing. */
+static scoped_restore_tmpl<int>
+make_scoped_restore_global (int value)
+{
+ return make_scoped_restore (&global, value);
+}
+
+static void
+run_tests ()
+{
+ /* Test that single-argument make_scoped_restore restores the
+ original value on scope exit. */
+ {
+ int integer = 0;
+ {
+ scoped_restore restore = make_scoped_restore (&integer);
+ SELF_CHECK (integer == 0);
+ integer = 1;
+ }
+ SELF_CHECK (integer == 0);
+ }
+
+ /* Same, with two-argument make_scoped_restore. */
+ {
+ int integer = 0;
+ {
+ scoped_restore restore = make_scoped_restore (&integer, 1);
+ SELF_CHECK (integer == 1);
+ }
+ SELF_CHECK (integer == 0);
+ }
+
+ /* Test releasing a scoped_restore. */
+ {
+ int integer = 0;
+ {
+ scoped_restore restore = make_scoped_restore (&integer, 1);
+ SELF_CHECK (integer == 1);
+ restore.release ();
+ }
+ /* The overridden value should persist. */
+ SELF_CHECK (integer == 1);
+ }
+
+ /* Test creating a scoped_restore with a value of a type convertible
+ to T. */
+ {
+ Base *base = nullptr;
+ Derived derived;
+ {
+ scoped_restore restore = make_scoped_restore (&base, &derived);
+
+ SELF_CHECK (base == &derived);
+ }
+ SELF_CHECK (base == nullptr);
+ }
+
+ /* Test calling a function that returns a scoped restore. Makes
+ sure that if the compiler emits a call to the copy ctor, that we
+ still do the right thing. */
+ {
+ {
+ SELF_CHECK (global == 0);
+ scoped_restore restore = make_scoped_restore_global (1);
+ SELF_CHECK (global == 1);
+ }
+ SELF_CHECK (global == 0);
+ }
+}
+
+} /* namespace scoped_restore_tests */
+} /* namespace selftests */
+
+void
+_initialize_scoped_restore_selftests ()
+{
+ register_self_test (selftests::scoped_restore_tests::run_tests);
+}
projects / deliverable / binutils-gdb.git / commitdiff
