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/* Poison symbols at compile time.
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/>. */
#ifndef COMMON_POISON_H
#define COMMON_POISON_H
#include "traits.h"
/* Poison memset of non-POD types. The idea is catching invalid
initialization of non-POD structs that is easy to be introduced as
side effect of refactoring. For example, say this:
struct S { VEC(foo_s) *m_data; };
is converted to this at some point:
struct S {
S() { m_data.reserve (10); }
std::vector<foo> m_data;
};
and old code was initializing S objects like this:
struct S s;
memset (&s, 0, sizeof (S)); // whoops, now wipes vector.
Declaring memset as deleted for non-POD types makes the memset above
be a compile-time error. */
/* Helper for SFINAE. True if "T *" is memsettable. I.e., if T is
either void, or POD. */
template<typename T>
struct IsMemsettable
: gdb::Or<std::is_void<T>,
std::is_pod<T>>
{};
template <typename T,
typename = gdb::Requires<gdb::Not<IsMemsettable<T>>>>
void *memset (T *s, int c, size_t n) = delete;
#if HAVE_IS_TRIVIALLY_COPYABLE
/* Similarly, poison memcpy and memmove of non trivially-copyable
types, which is undefined. */
/* True if "T *" is relocatable. I.e., copyable with memcpy/memmove.
I.e., T is either trivially copyable, or void. */
template<typename T>
struct IsRelocatable
: gdb::Or<std::is_void<T>,
std::is_trivially_copyable<T>>
{};
/* True if both source and destination are relocatable. */
template <typename D, typename S>
using BothAreRelocatable
= gdb::And<IsRelocatable<D>, IsRelocatable<S>>;
template <typename D, typename S,
typename = gdb::Requires<gdb::Not<BothAreRelocatable<D, S>>>>
void *memcpy (D *dest, const S *src, size_t n) = delete;
template <typename D, typename S,
typename = gdb::Requires<gdb::Not<BothAreRelocatable<D, S>>>>
void *memmove (D *dest, const S *src, size_t n) = delete;
#endif /* HAVE_IS_TRIVIALLY_COPYABLE */
#endif /* COMMON_POISON_H */
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