This fixes the following build error with clang/libc++, reported at
<https://sourceware.org/ml/gdb-patches/2019-01/msg00537.html>:
(...)
In file included from breakpoint.c:34:
In file included from ./inferior.h:54:
./common/forward-scope-exit.h:98:7: error: no matching constructor for
initialization of 'decltype(std::bind(&delete_longjmp_breakpoint,
std::declval<int>()))' (aka '__bind<void (*)(int), int>')
: m_bind_function (std::bind (function, args...))
^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./common/gdb_optional.h:155:19: note: in instantiation of member
function 'detail::forward_scope_exit<void (int),
&delete_longjmp_breakpoint, void (int)>::forward_scope_exit' requested
here
new (&m_item) T (std::forward<Args>(args)...);
^
breakpoint.c:11127:18: note: in instantiation of function template
specialization 'gdb::optional<detail::forward_scope_exit<void (int),
&delete_longjmp_breakpoint, void (int)> >::emplace<int &>' requested
here
lj_deleter.emplace (thread);
^
/Applications/Xcode-10.1.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/functional:2220:7:
note: candidate constructor (the implicit copy constructor) not
viable: no known conversion from '__bind<[...], int &>' to 'const
__bind<[...], int>' for 1st argument
class __bind
^
(...)
I don't really know why I ended up with a copy here. We can just pass
the arguments directly to the being-constructed bind.
gdb/ChangeLog:
2019-01-24 Pedro Alves <palves@redhat.com>
* common/forward-scope-exit.h
(forward_scope_exit::forward_scope_exit): Pass arguments to
m_bind_function directly, instead of creating a std::bind and
copying that.
This adds a template that can be used to automatically instantiate
scope_exit-like types that wrap some cleanup function. The
instantiated type has a ctor that has the same interface as the
wrapped function. While the "magic" is just straight C++11, the
intended use is via the FORWARD_SCOPE_EXIT macro, which is a minimal
macro that avoids spelling out the wrapped function name more than
once:
void some_function (int foo, object *bar);
using some_function_fce = FORWARD_SCOPE_EXIT (some_function);
some_function_fce cleanup (some_int, some_obj_ptr);
The above runs:
some_function (some_int, some_obj_ptr);
at scope exit.
This is mainly useful as opposed to a simpler SCOPE_EXIT when you need
to:
- cancel the scope_exit, in which case you need the object's name
- wrap the scope_exit in a gdb::optional, in which case you need the
scope_exit's type in advance.
More details in the code comments.
gdb/ChangeLog:
2019-01-23 Pedro Alves <palves@redhat.com>
Andrew Burgess <andrew.burgess@embecosm.com>
* common/forward-scope-exit.h: New file.
Pedro Alves