I noticed in passing that the include guard in the file
gdbsupport/gdb-checked-static-cast.h was wrong, it includes the word
DYNAMIC when STATIC would be better, fixed in this commit.
There should be no user visible changes after this commit.
This commit:
commit 6fe4779ac4
Date: Sat Feb 24 11:00:20 2024 +0100
[gdb/build] Fix static cast of virtual base
addressed an issue where GDB would not compile in production mode due
to a use of gdb::checked_static_cast. The problem was that we were
asking GDB to cast from a virtual base class to a sub-class, this
works fine when using dynamic_cast, but does not work with
static_cast.
The gdb::checked_static_cast actually uses dynamic_cast under the hood
in development mode in order to ensure that the cast is valid, while
in a production build we use static_cast as this is more efficient.
What this meant however, was that when gdb::checked_static_cast was
used to cast from a virtual base class, the dynamic_cast of a
non-production build worked fine, while the production build's
static_cast caused a build failure.
However, the gdb::checked_static_cast function already contains some
static_assert calls that are intended to catch any issues with invalid
type casting, the goal of these asserts was to prevent issues like
this: the build only failing in production mode. Clearly the current
asserts are not enough.
I don't think there is a std::is_virtual_base type trait check, so
what I propose instead is that in non-production mode we also make use
of static_cast. This will ensure that any errors that crop up in
production mode should also be revealed in non-production mode, and
should catch issues like this in the future.
There should be no user visible changes after this commit.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31399
Co-Authored-By: Simon Marchi <simon.marchi@polymtl.ca>
This commit is the result of the following actions:
- Running gdb/copyright.py to update all of the copyright headers to
include 2024,
- Manually updating a few files the copyright.py script told me to
update, these files had copyright headers embedded within the
file,
- Regenerating gdbsupport/Makefile.in to refresh it's copyright
date,
- Using grep to find other files that still mentioned 2023. If
these files were updated last year from 2022 to 2023 then I've
updated them this year to 2024.
I'm sure I've probably missed some dates. Feel free to fix them up as
you spot them.
Add a checked_static_cast overload that works with references. A bad
dynamic cast with references throws std::bad_cast, it would be possible
to implement the new overload based on that, but it seemed simpler to
just piggy back off the existing function.
I found some potential uses of this new overload in amd-dbgapi-target.c,
update them to illustrate the use of the new overload. To build
amd-dbgapi-target.c, on needs the amd-dbgapi library, which I don't
expect many people to have. But I have it, and it builds fine here. I
did test the new overload by making a purposely bad cast and it did
catch it.
Change-Id: Id6b6a7db09fe3b4aa43cddb60575ff5f46761e96
Reviewed-By: Lancelot SIX <lsix@lancelotsix.com>
Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Both static_cast and dynamic_cast handle nullptr (they return nullptr),
so I think checked_static_cast should too. This will allow doing a null
check after a checked_static_cast:
cooked_index_vector *table
= (gdb::checked_static_cast<cooked_index_vector *>
(per_bfd->index_table.get ()));
if (table != nullptr)
return;
Change-Id: If5c3134e63696f8e417c87b5f3901240c9f7ea97
This commit is the result of running the gdb/copyright.py script,
which automated the update of the copyright year range for all
source files managed by the GDB project to be updated to include
year 2023.
This commit was inspired by these mailing list posts:
https://sourceware.org/pipermail/gdb-patches/2022-June/190323.htmlhttps://sourceware.org/pipermail/gdb-patches/2022-April/188098.html
The idea is to add a new function gdb::checked_static_cast, which can,
in some cases, be used as a drop-in replacement for static_cast. And
so, if I previously wrote this:
BaseClass *base = get_base_class_pointer ();
DerivedClass *derived = static_cast<DerivedClass *> (base);
I can now write:
BaseClass *base = get_base_class_pointer ();
DerivedClass *derived = gdb::checked_static_cast<DerivedClass *> (base);
The requirement is that BaseClass and DerivedClass must be
polymorphic.
The benefit of making this change is that, when GDB is built in
developer mode, a run-time check will be made to ensure that `base`
really is of type DerivedClass before the cast is performed. If
`base` is not of type DerivedClass then GDB will assert.
In a non-developer build gdb::checked_static_cast is equivalent to a
static_cast, and there should be no performance difference.
This commit adds the support function, but does not make use of this
function, a use will be added in the next commit.
Co-Authored-By: Pedro Alves <pedro@palves.net>
Co-Authored-By: Tom Tromey <tom@tromey.com>
